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Rosa Bellavita,1,* Marialuisa Piccolo,1,* Linda Leone,2 Maria Grazia Ferraro,1,3 Principia Dardano,4 Luca De Stefano,4 Flavia Nastri,2 Carlo Irace,1 Annarita Falanga,5 Stefania Galdiero1,* 1Department of Pharmacy, School of Medicine, University of Naples ‘Federico II’, Napoli, Italy; 2Department of Chemical Sciences, University of Napoli “Federico II”, Naples, Italy; 3School of Infection and Immunity, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK; 4Institute of Applied Sciences and Intelligent Systems, Consiglio Nazionale delle Ricerche, Naples, Italy; 5Department of Agricultural Science, University of Naples “Federico II”, Portici, Italy*These authors contributed equally to this workCorrespondence: Stefania Galdiero, Email stefania.galdiero@unina.itIntroduction: The design of delivery tools that efficiently transport drugs into cells remains a major challenge in drug development for most pathological conditions. Triple-negative breast cancer (TNBC) is a very aggressive subtype of breast cancer with poor prognosis and limited effective therapeutic options.Purpose: In TNBC treatment, chemotherapy remains the milestone, and doxorubicin (Dox) represents the first-line systemic treatment; however, its non-selective distribution causes a cascade of side effects. To address these problems, we developed a delivery platform based on the self-assembly of amphiphilic peptides carrying several moieties on their surfaces, aimed at targeting, enhancing penetration, and therapy.Methods: Through a single-step self-assembly process, we used amphiphilic peptides to obtain nanofibers decorated on their surfaces with the selected moieties. The surface of the nanofiber was decorated with a cell-penetrating peptide (gH625), an EGFR-targeting peptide (P22), and Dox bound to the cleavage sequence selectively recognized and cleaved by MMP-9 to obtain on-demand drug release. Detailed physicochemical and cellular analyses were performed.Results: The obtained nanofiber (NF-Dox) had a length of 250 nm and a diameter of 10 nm, and it was stable under dilution, ionic strength, and different pH environments. The biological results showed that the presence of gH625 favored the complete internalization of NF-Dox after 1h in MDA-MB 231 cells, mainly through a translocation mechanism. Interestingly, we observed the absence of toxicity of the carrier (NF) on both healthy cells such as HaCaT and TNBC cancer lines, while a similar antiproliferative effect was observed on TNBC cells after the treatment with the free-Dox at 50 μM and NF-Dox carrying 7.5 μM of Dox.Discussion: We envision that this platform is extremely versatile and can be used to efficiently carry and deliver diverse moieties. The knowledge acquired from this study will provide important guidelines for applications in basic research and biomedicine. Keywords: self-assembling peptides, triple negative breast cancer, nanofiber, on-demand strategy, doxorubicin

Objective: The escalating prevalence of noncarious tooth wear stands as a critical concern in the backdrop of evolving lifestyles and dietary patterns. Dental erosion, a progressive condition induced by both endogenous and exogenous acidic influences, directly impacts enamel integrity, resulting in surface loss. The contemporary surge in carbonated beverage consumption further exacerbates this erosive milieu, underscoring the urgency for dental practitioners to adopt meticulous treatment strategies. Existing literature underscores a noteworthy 94% reduction in tooth erosion risk for individuals abstaining from sweetened soft beverages, emphasizing the imperative for a well-devised remineralization protocol to counter demineralized surfaces. Methodology: Seventy-three enamel specimens were taken. Forty samples were subjected to pre-operative hardness testing, and five samples were subjected to baseline EDX evaluation followed by grouping of samples (Group 1 = control Group; Group 2 = casein phosphopeptide-amorphous calcium phosphate fluoride [CPP-ACPF] Group; Group 3 = Biomin F Group; and Group 4 = self-assembling peptide [SAP] P-114 Group). A demineralization-remineralization cycle was carried out for 5 days followed by testing through Vickers Microhardness Tester, EDX Evaluation, and Scanning Electron Microscopy (SEM) Imaging. Statistical analysis was performed using one-way analysis of variance followed by intergroup analysis using Tukey's post hoc test with SPSS software 25.0 version. Results: The mean percentage change in microhardness values was 30.05% in Group 1, 24.21% in Group 2, 18.85% in Group 3, and 12.08% in Group 4. The mean Ca/P ratio of samples tested through EDAX was 2.20 at baseline, 1.40 in Group 1 (Control Group), 1.62 in Group 2 (CPP-ACPF), 1.82 in Group 3 (Biomin F), and 2.01 in Group 4 (SAP-P114). Postintervention values were statistically significant from baseline values in both parameters. Conclusion: Curodont Protect exhibits superior efficacy, offering valuable insights for future in vivo studies and clinical applications. The multifaceted evaluation, encompassing microhardness testing, SEM analysis, and EDXS assessment, contributes to a nuanced interpretation of the agents' impact, paving the way for informed decisions in clinical practice and future research endeavors. [ABSTRACT FROM AUTHOR]

Cannabidiol (CBD), nonpsychotropic cannabinoid found in Cannabis sativa, is a very promising drug candidate offering many differential effects such as sedative, antiinflammatory, antioxidant, and neuroprotective properties. Nevertheless, the therapeutic use of CBD is hindered by its lack of water solubility and relatively low bioavailability. Various carriers have been used to address the solubility issues of CBD and other highly lipophilic drugs so far. However, self-assembled peptide nanostructures as carrier have not been used to improve the water solubility of CBD yet. In this study, a self-assembling peptide micelle was demonstrated to be an effective vehicle for encapsulation of CBD and increased its aqueous solubility up to 2000-fold compared to CBD itself. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) poses a significant global health risk as a consequence of misuse of antibiotics. Owing to the increasing antimicrobial resistance, it became imperative to develop novel molecules and materials with antimicrobial properties. Porphyrins and metalloporphyrins are compounds which present antimicrobial properties especially after irradiation. As a consequence, porphyrinoids have recently been utilized as antimicrobial agents in antimicrobial photodynamic inactivation in bacteria and other microorganisms. Herein, we report the encapsulation of porphyrins into peptide hydrogels which serve as delivery vehicles. We selected the self-assembling Fmoc-Phe-Phe dipeptide, a potent gelator, as a scaffold due to its previously reported biocompatibility and three different water-soluble porphyrins as photosensitizers. We evaluated the structural, mechanical and in vitro degradation properties of these hydrogels, their interaction with NIH3T3 mouse skin fibroblasts, and we assessed their antimicrobial efficacy against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria. We found out that the hydrogels are cytocompatible and display antimicrobial efficiency against both strains with the zinc porphyrins being more efficient. Therefore, these hydrogels present a promising alternative for combating bacterial infections in the face of growing AMR concerns. [ABSTRACT FROM AUTHOR]

Simple Summary: There are no Food and Drug Administration (FDA)-approved drugs for traumatic brain injury (TBI). The available treatments have limitations, including limited access to the injury site, mainly due to the complex pathology of TBI and the presence of the blood–brain barrier. This review collects and discusses the available literature on the use of biomaterials, mainly hydrogels, including self-assembling peptides and electrospun nanofibers to enhance the therapeutic outcomes of TBI. The challenges and limitations that such an approach faces are also exposed. Traumatic brain injury (TBI) is a leading cause of mortality and long-term impairment globally. TBI has a dynamic pathology, encompassing a variety of metabolic and molecular events that occur in two phases: primary and secondary. A forceful external blow to the brain initiates the primary phase, followed by a secondary phase that involves the release of calcium ions (Ca2+) and the initiation of a cascade of inflammatory processes, including mitochondrial dysfunction, a rise in oxidative stress, activation of glial cells, and damage to the blood–brain barrier (BBB), resulting in paracellular leakage. Currently, there are no FDA-approved drugs for TBI, but existing approaches rely on delivering micro- and macromolecular treatments, which are constrained by the BBB, poor retention, off-target toxicity, and the complex pathology of TBI. Therefore, there is a demand for innovative and alternative therapeutics with effective delivery tactics for the diagnosis and treatment of TBI. Tissue engineering, which includes the use of biomaterials, is one such alternative approach. Biomaterials, such as hydrogels, including self-assembling peptides and electrospun nanofibers, can be used alone or in combination with neuronal stem cells to induce neurite outgrowth, the differentiation of human neural stem cells, and nerve gap bridging in TBI. This review examines the inclusion of biomaterials as potential treatments for TBI, including their types, synthesis, and mechanisms of action. This review also discusses the challenges faced by the use of biomaterials in TBI, including the development of biodegradable, biocompatible, and mechanically flexible biomaterials and, if combined with stem cells, the survival rate of the transplanted stem cells. A better understanding of the mechanisms and drawbacks of these novel therapeutic approaches will help to guide the design of future TBI therapies. [ABSTRACT FROM AUTHOR]

Retinal ischemia is involved in the occurrence and development of various eye diseases, including glaucoma, diabetic retinopathy, and central retinal artery occlusion. To the best of our knowledge, few studies have reported self‐assembling peptide natural products for the suppression of ocular inflammation and oxidative stress. Herein, a self‐assembling peptide GFFYE is designed and synthesized, which can transform the non‐hydrophilicity of rhein into an amphiphilic sustained‐release therapeutic agent, and rhein‐based therapeutic nanofibers (abbreviated as Rh‐GFFYE) are constructed for the treatment of retinal ischemia‐reperfusion (RIR) injury. Rh‐GFFYE significantly ameliorates oxidative stress and inflammation in an in vitro oxygen‐glucose deprivation (OGD) model of retinal ischemia and a rat model of RIR injury. Rh‐GFFYE also significantly enhances retinal electrophysiological recovery and exhibits good biocompatibility. Importantly, Rh‐GFFYE also promotes the transition of M1‐type macrophages to the M2 type, ultimately altering the pro‐inflammatory microenvironment. Further investigation of the treatment mechanism indicates that Rh‐GFFYE activates the PI3K/AKT/mTOR signaling pathway to reduce oxidative stress and inhibits the NF‐κB and STAT3 signaling pathways to affect inflammation and macrophage polarization. In conclusion, the rhein‐loaded nanoplatform alleviates RIR injury by modulating the retinal microenvironment. The findings are expected to promote the clinical application of hydrophobic natural products in RIR injury‐associated eye diseases. [ABSTRACT FROM AUTHOR]

In this review, we focused on recent efforts in the design and development of materials with biomimetic properties. Innovative methods promise to emulate cell microenvironments and tissue functions, but many aspects regarding cellular communication, motility, and responsiveness remain to be explained. We photographed the state-of-the-art advancements in biomimetics, and discussed the complexity of a "bottom-up" artificial construction of living systems, with particular highlights on hydrogels, collagen-based composites, surface modifications, and three-dimensional (3D) bioprinting applications. Fast-paced 3D printing and artificial intelligence, nevertheless, collide with reality: How difficult can it be to build reproducible biomimetic materials at a real scale in line with the complexity of living systems? Nowadays, science is in urgent need of bioengineering technologies for the practical use of bioinspired and biomimetics for medicine and clinics. [ABSTRACT FROM AUTHOR]

Spinal cord regeneration using stem cell transplantation is a promising strategy for regenerative therapy. Stem cells transplanted onto scaffolds that can mimic natural extracellular matrix (ECM) have the potential to significantly improve outcomes. In this study, we strived to develop a cell carrier by culturing neural stem cells (NSCs) onto electrospun 2D and 3D constructs made up of specific crosslinked functionalized self-assembling peptides (SAPs) featuring enhanced biomimetic and biomechanical properties. Morphology, architecture, and secondary structures of electrospun scaffolds in the solid-state and electrospinning solution were studied step by step. Morphological studies showed the benefit of mixed peptides and surfactants as additives to form thinner, uniform, and defect-free fibers. It has been observed that β-sheet conformation as evidence of self-assembling has been predominant throughout the process except for the electrospinning solution. In vitro NSCs seeded on electrospun SAP scaffolds in 2D and 3D conditions displayed desirable proliferation, viability, and differentiation in comparison to the gold standard. In vivo biocompatibility assay confirmed the permissibility of implanted fibrous channels by foreign body reaction. The results of this study demonstrated that fibrous 2D/3D electrospun SAP scaffolds, when shaped as micro-channels, can be suitable to support NSC transplantation for regeneration following spinal cord injury. [ABSTRACT FROM AUTHOR]

Abstract Retinal ischemia is involved in the occurrence and development of various eye diseases, including glaucoma, diabetic retinopathy, and central retinal artery occlusion. To the best of our knowledge, few studies have reported self‐assembling peptide natural products for the suppression of ocular inflammation and oxidative stress. Herein, a self‐assembling peptide GFFYE is designed and synthesized, which can transform the non‐hydrophilicity of rhein into an amphiphilic sustained‐release therapeutic agent, and rhein‐based therapeutic nanofibers (abbreviated as Rh‐GFFYE) are constructed for the treatment of retinal ischemia‐reperfusion (RIR) injury. Rh‐GFFYE significantly ameliorates oxidative stress and inflammation in an in vitro oxygen‐glucose deprivation (OGD) model of retinal ischemia and a rat model of RIR injury. Rh‐GFFYE also significantly enhances retinal electrophysiological recovery and exhibits good biocompatibility. Importantly, Rh‐GFFYE also promotes the transition of M1‐type macrophages to the M2 type, ultimately altering the pro‐inflammatory microenvironment. Further investigation of the treatment mechanism indicates that Rh‐GFFYE activates the PI3K/AKT/mTOR signaling pathway to reduce oxidative stress and inhibits the NF‐κB and STAT3 signaling pathways to affect inflammation and macrophage polarization. In conclusion, the rhein‐loaded nanoplatform alleviates RIR injury by modulating the retinal microenvironment. The findings are expected to promote the clinical application of hydrophobic natural products in RIR injury‐associated eye diseases.

In severe peripheral nerve injuries, nerve conduits (NCs) are good alternatives to autografts/allografts; however, the results the available devices guarantee for are still not fully satisfactory. Herein, differently bioactivated NCs based on the new polymer oxidized polyvinyl alcohol (OxPVA) are compared in a rat model of sciatic nerve neurotmesis (gap: 5 mm; end point: 6 weeks). Thirty Sprague Dawley rats are randomized to 6 groups: Reverse Autograft (RA); Reaxon®; OxPVA; OxPVA + EAK (self-assembling peptide, mechanical incorporation); OxPVA + EAK-YIGSR (mechanical incorporation); OxPVA + Nerve Growth Factor (NGF) (adsorption). Preliminarily, all OxPVA-based devices are comparable with Reaxon® in Sciatic Functional Index score and gait analysis; moreover, all conduits sustain nerve regeneration (S100, β-tubulin) without showing substantial inflammation (CD3, F4/80) evidences. Following morphometric analyses, OxPVA confirms its potential in PNI repair (comparable with Reaxon®) whereas OxPVA + EAK-YIGSR stands out for its myelinated axons total number and density, revealing promising in injury recovery and for future application in clinical practice.

Self-assembling peptides (SAPs) have enormous potential in medical and biological applications, particularly noninvasive tumor therapy. SAPs self-assembly is governed by multiple non-covalent interactions and results in the formation of a variety of morphological features. SAPs can be assembled in a variety of ways, including chemical conjugation and physical encapsulation, to incorporate multiple bioactive motifs. Peptide-based nanomaterials are used for chemotherapy, delivery vehicles, immunotherapy, and noninvasive tumor therapies (e.g. photodynamic therapy) by employing the self-assembling properties of peptides. The recent increase of SAPs is almost entirely due to their excellent biocompatibility, responsiveness toward tumor microenvironment, multivalency, and structural versatility. Synergistic therapy is a more effective and powerful approach to treat the tumor. Notably, SAPs can be used to subtly combine various treatments. Importantly, SAPs are capable of subtly making the combination of various treatments. This review describes mechanisms of peptides self-assemble into various structures and their biomedical applications with a focus on possible treatments.

The field of supramolecular peptides self-assembly has undergone outstanding growth since the early 1990s after the serendipitously discovery by Shuguang Zhang of an ionic self-complementary peptide as a repeating segment in a yeast protein. From then on, the field expanded at an accelerating pace and these self-assembled materials have become an integral part of a broad plethora of designer supramolecular nanomaterials useful for different applications ranging from 3D tissue cell cultures, regenerative medicine, up to optoelectronics. However, the supramolecular peptide based-nanomaterials available thus far for regenerative medicine still lack the dynamic complexity found in the biological structures that mediate regeneration. Indeed, self-assembling peptide (SAPs) suffer from poor mechanical stability, losing mechanical properties at low strains. Just like the extracellular matrix (ECM) of living systems, the chemical structure of the SAP-biomaterials should concurrently contain non-covalent and covalent bonds, bringing, respectively, infinite and finite lifetimes of interactions to obtain a reversibly dynamic matrix. In this review, will be highlighted the major advantages and current limitations of SAP-based biomaterials, and it will be discussed the most widely used strategies for precisely tune their mechanical properties (stiffness, resilience, strain-failure, stress resistance), describing recent and promising approaches in tissue engineering, regenerative medicine, and beyond.

Abstract Organotypic skin cultures represent in vitro models of skin which can be used for disease modeling, tissue engineering, and screening applications. Non‐human collagen is currently the gold standard material used for the construction of the supporting matrix, however, its clinical applications are limited due to its xenogeneic origin. We have developed a novel peptide hydrogel‐based skin construct that shows a pluristratified epidermis, basement membrane, and dermal compartment after 3 weeks of in vitro culture. Peptide‐based constructs were compared to collagen‐based constructs and stratification marker expression was histologically higher in peptide constructs than in collagen constructs. Transepithelial electrical resistance also showed mature barrier function in peptide constructs. This study presents a novel application of the self‐assembling peptide hydrogel in a defined xeno‐free in vitro system.

Bioinspired self-assembly is a bottom-up strategy enabling biologically sophisticated nanostructured biogels that can mimic natural tissue. Self-assembling peptides (SAPs), carefully designed, form signal-rich supramolecular nanostructures that intertwine to form a hydrogel material that can be used for a range of cell and tissue engineering scaffolds. Using the tools of nature, they are a versatile framework for the supply and presentation of important biological factors. Recent developments have shown promise for many applications such as therapeutic gene, drug and cell delivery and yet are stable enough for large-scale tissue engineering. This is due to their excellent programmability—features can be incorporated for innate biocompatibility, biodegradability, synthetic feasibility, biological functionality and responsiveness to external stimuli. SAPs can be used independently or combined with other (macro)molecules to recapitulate surprisingly complex biological functions in a simple framework. It is easy to accomplish localized delivery, since they can be injected and can deliver targeted and sustained effects. In this review, we discuss the categories of SAPs, applications for gene and drug delivery, and their inherent design challenges. We highlight selected applications from the literature and make suggestions to advance the field with SAPs as a simple, yet smart delivery platform for emerging BioMedTech applications. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) poses a significant global health risk as a consequence of misuse of antibiotics. Owing to the increasing antimicrobial resistance, it became imperative to develop novel molecules and materials with antimicrobial properties. Porphyrins and metalloporphyrins are compounds which present antimicrobial properties especially after irradiation. As a consequence, porphyrinoids have recently been utilized as antimicrobial agents in antimicrobial photodynamic inactivation in bacteria and other microorganisms. Herein, we report the encapsulation of porphyrins into peptide hydrogels which serve as delivery vehicles. We selected the self-assembling Fmoc-Phe-Phe dipeptide, a potent gelator, as a scaffold due to its previously reported biocompatibility and three different water-soluble porphyrins as photosensitizers. We evaluated the structural, mechanical and in vitro degradation properties of these hydrogels, their interaction with NIH3T3 mouse skin fibroblasts, and we assessed their antimicrobial efficacy against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria. We found out that the hydrogels are cytocompatible and display antimicrobial efficiency against both strains with the zinc porphyrins being more efficient. Therefore, these hydrogels present a promising alternative for combating bacterial infections in the face of growing AMR concerns.

Traumatic brain injury (TBI) is a leading cause of mortality and long-term impairment globally. TBI has a dynamic pathology, encompassing a variety of metabolic and molecular events that occur in two phases: primary and secondary. A forceful external blow to the brain initiates the primary phase, followed by a secondary phase that involves the release of calcium ions (Ca2+) and the initiation of a cascade of inflammatory processes, including mitochondrial dysfunction, a rise in oxidative stress, activation of glial cells, and damage to the blood–brain barrier (BBB), resulting in paracellular leakage. Currently, there are no FDA-approved drugs for TBI, but existing approaches rely on delivering micro- and macromolecular treatments, which are constrained by the BBB, poor retention, off-target toxicity, and the complex pathology of TBI. Therefore, there is a demand for innovative and alternative therapeutics with effective delivery tactics for the diagnosis and treatment of TBI. Tissue engineering, which includes the use of biomaterials, is one such alternative approach. Biomaterials, such as hydrogels, including self-assembling peptides and electrospun nanofibers, can be used alone or in combination with neuronal stem cells to induce neurite outgrowth, the differentiation of human neural stem cells, and nerve gap bridging in TBI. This review examines the inclusion of biomaterials as potential treatments for TBI, including their types, synthesis, and mechanisms of action. This review also discusses the challenges faced by the use of biomaterials in TBI, including the development of biodegradable, biocompatible, and mechanically flexible biomaterials and, if combined with stem cells, the survival rate of the transplanted stem cells. A better understanding of the mechanisms and drawbacks of these novel therapeutic approaches will help to guide the design of future TBI therapies.

The field of supramolecular peptides self-assembly has undergone outstanding growth since the early 1990s after the serendipitously discovery by Shuguang Zhang of an ionic self-complementary peptide as a repeating segment in a yeast protein. From then on, the field expanded at an accelerating pace and these self-assembled materials have become an integral part of a broad plethora of designer supramolecular nanomaterials useful for different applications ranging from 3D tissue cell cultures, regenerative medicine, up to optoelectronics. However, the supramolecular peptide based-nanomaterials available thus far for regenerative medicine still lack the dynamic complexity found in the biological structures that mediate regeneration. Indeed, self-assembling peptide (SAPs) suffer from poor mechanical stability, losing mechanical properties at low strains. Just like the extracellular matrix (ECM) of living systems, the chemical structure of the SAP-biomaterials should concurrently contain non-covalent and covalent bonds, bringing, respectively, infinite and finite lifetimes of interactions to obtain a reversibly dynamic matrix. In this review, will be highlighted the major advantages and current limitations of SAP-based biomaterials, and it will be discussed the most widely used strategies for precisely tune their mechanical properties (stiffness, resilience, strain-failure, stress resistance), describing recent and promising approaches in tissue engineering, regenerative medicine, and beyond. [ABSTRACT FROM AUTHOR]

Nerve guidance conduits with hollow lumen fail to regenerate critical-sized peripheral nerve defects (15 mm in rats and 25 mm in humans), which can be improved by a beneficial intraluminal microenvironment. However, individual cues provided by intraluminal filling materials are inadequate to eliminate the functional gap between regenerated nerves and normal nerves. Herein, an aligned fibrin/functionalized self-assembling peptide (AFG/fSAP) interpenetrating nanofiber hydrogel that exerting synergistic topographical and biochemical cues for peripheral nerve regeneration is constructed via electrospinning and molecular self-assembly. The hydrogel possesses an aligned structure, high water content, appropriate mechanical properties and suitable biodegradation capabilities for nerve repair, which enhances the alignment and neurotrophin secretion of primary Schwann cells (SCs) in vitro, and successfully bridges a 15-mm sciatic nerve gap in rats in vivo. The rats transplanted with the AFG/fSAP hydrogel exhibit satisfactory morphological and functional recovery in myelinated nerve fibers and innervated muscles. The motor function recovery facilitated by the AFG/fSAP hydrogel is comparable with that of autografts. Moreover, the AFG/fSAP hydrogel upregulates the regeneration-associated gene expression and activates the PI3K/Akt and MAPK signaling pathways in the regenerated nerve. Altogether, the AFG/fSAP hydrogel represents a promising approach for peripheral nerve repair through an integration of structural guidance and biochemical stimulation.

Human pancreatic islets transplantation is an experimental therapeutic treatment for Type I Diabetes. Limited islets lifespan in culture remains the main drawback, due to the absence of native extracellular matrix as mechanical support after their enzymatic and mechanical isolation procedure. Extending the limited islets lifespan by creating a long-term in vitro culture remains a challenge. In this study, three biomimetic self-assembling peptides were proposed as potential candidates to recreate in vitro a pancreatic extracellular matrix, with the aim to mechanically and biologically support human pancreatic islets, by creating a three-dimensional culture system. The embedded human islets were analyzed for morphology and functionality in long-term cultures (14-and 28-days), by evaluating β-cells content, endocrine component, and extracellular matrix constituents. The three-dimensional support provided by HYDROSAP scaffold, and cultured into MIAMI medium, displayed a preserved islets functionality, a maintained rounded islets morphology and an invariable islets diameter up to 4 weeks, with results analogues to freshly-isolated islets. In vivo efficacy studies of the in vitro 3D cell culture system are ongoing; however, preliminary data suggest that human pancreatic islets pre-cultured for 2 weeks in HYDROSAP hydrogels and transplanted under subrenal capsule may restore normoglycemia in diabetic mice. Therefore, engineered self-assembling peptide scaffolds may provide a useful platform for long-term maintenance and preservation of functional human pancreatic islets in vitro.

Structured abstract: Abstract: The self-assembling and gelation properties of a bioactive peptide derived from bovine casein (FFVAPFPEVFGK) were studied in the peptide's natural form (uncapped, uncapFFV) and capped with protecting groups added to both termini (capped, capFFV). Although the natural peptide (uncapFFV) did not demonstrate self-assembly, the capped peptide (capFFV) spontaneously self-assembled and formed a self-supporting gel. Variations in peptide concentration and incubation time influenced the gel's mechanical properties, suggesting the peptide's properties could be tuned and exploited for different applications. These results suggest that food-derived bioactive peptides have good potential for self-assembly and therefore utilisation as gels in functional foods and nutraceuticals. Background: Self-assembly is a natural phenomenon that occurs in many fundamental biological processes. Some peptides can self-assemble and form gels with tunable properties under given conditions. These properties, along with peptide bioactivity, can be combined to make unique biomaterials. Instead of synthesising the self-assembling bioactive peptides, we aim to extract them from natural sources. In order to use these peptides for different applications, it is essential to understand how we can trigger self-assembly and optimise the assembly conditions of these peptide gels. Scope: The self-assembling and gelation properties of a bioactive peptide derived from bovine casein (FFVAPFPEVFGK) were studied in the peptide's natural form (uncapped, uncapFFV) and capped with protecting groups added to both termini (capped, capFFV). Major conclusions: Although the natural peptide (uncapFFV) did not demonstrate self-assembly, the capped peptide (capFFV) spontaneously self-assembled and formed a self-supporting gel. Variations in peptide concentration and incubation time influenced the gel's mechanical properties, suggesting the peptide's properties could be tuned and exploited for different applications. General significance: These results suggest that food-derived bioactive peptides have good potential for self-assembly and therefore utilisation as gels in functional foods and nutraceuticals.

Peptide-based hydrogels are of great interest in the biomedical field according to their biocompatibility, simple structure and tunable properties via sequence modification. In recent years, multicomponent assembly of peptides have expanded the possibilities to produce more versatile hydrogels, by blending gelating peptides with different type of peptides to add new features. In the present study, the assembly of gelating P5 peptide SFFSF blended with P21 peptide, SFFSFGVPGVGVPGVGSFFSF, an elastin-inspired peptides or, alternatively, with FF dipeptide, was investigated by oscillatory rheology and different microscopy techniques in order to shed light on the nanotopologies formed by the self-assembled peptide mixtures. Our data show that, depending on the added peptides, cooperative or disruptive assembly can be observed giving rise to distinct nanotopologies to which correspond different mechanical properties that could be exploited to fabricate materials with desired properties. [ABSTRACT FROM AUTHOR]

Oxidized polyvinyl alcohol (OxPVA) is a new polymer for the fabrication of nerve conduits (NCs). Looking for OxPVA device optimization and coupling it with a natural sheath may boost bioactivity. Thus, OxPVA/chitosan sponges (ChS) as hybrid scaffolds were investigated to predict in the vivo behaviour of two-layered NCs. To encourage interaction with cells, ChS were functionalized with the self-assembling-peptide (SAP) EAK, without/with the laminin-derived sequences -IKVAV/-YIGSR. Thus, ChS and the hybrid scaffolds were characterized for mechanical properties, ultrastructure (Scanning Electron Microscopy, SEM), bioactivity, and biocompatibility. Regarding mechanical analysis, the peptide-free ChS showed the highest values of compressive modulus and maximum stress. However, among +EAK groups, ChS+EAK showed a significantly higher maximum stress than that found for ChS+EAK-IKVAV and ChS+EAK-YIGSR. Considering ultrastructure, microporous interconnections were tighter in both the OxPVA/ChS and +EAK groups than in the others; all the scaffolds induced SH-SY5Y cells' adhesion/proliferation, with significant differences from day 7 and a higher total cell number for OxPVA/ChS+EAK scaffolds, in accordance with SEM. The scaffolds elicited only a slight inflammation after 14 days of subcutaneous implantation in Balb/c mice, proving biocompatibility. ChS porosity, EAK 3D features and neuro-friendly attitude (shared with IKVAV/YIGSR motifs) may confer to OxPVA certain bioactivity, laying the basis for future appealing NCs. [ABSTRACT FROM AUTHOR]

Organotypic skin cultures represent in vitro models of skin which can be used for disease modeling, tissue engineering, and screening applications. Non‐human collagen is currently the gold standard material used for the construction of the supporting matrix, however, its clinical applications are limited due to its xenogeneic origin. We have developed a novel peptide hydrogel‐based skin construct that shows a pluristratified epidermis, basement membrane, and dermal compartment after 3 weeks of in vitro culture. Peptide‐based constructs were compared to collagen‐based constructs and stratification marker expression was histologically higher in peptide constructs than in collagen constructs. Transepithelial electrical resistance also showed mature barrier function in peptide constructs. This study presents a novel application of the self‐assembling peptide hydrogel in a defined xeno‐free in vitro system. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) is the most aggressive central nervous system tumor, and standard treatment, including surgical resection, radiation, and chemotherapy, has not significantly improved patient outcomes over the last 20 years. Temozolomide (TMZ), the prodrug most commonly used to treat GBM, must pass the blood–brain barrier and requires a basic pH to convert to its active form. Due to these barriers, less than 30% of orally delivered TMZ reaches the central nervous system and becomes bioactive. In this work, we have developed a novel biomaterial delivery system to convert TMZ to its active form and that shows promise for intracellular TMZ delivery. Self-assembling peptides were characterized under several different assembly conditions and evaluated for TMZ loading and conversion. Both solvent and method of assembly were found to affect the supramolecular and secondary structure of peptide assemblies. Additionally, as peptides degraded in phosphate-buffered saline, TMZ was rapidly converted to its active form. This work demonstrates that peptide-based drug delivery systems can effectively create a local stimulus during drug delivery while remaining biocompatible. This principle could be used in many future biomedical applications in addition to cancer treatment, such as wound healing and regenerative medicine. [ABSTRACT FROM AUTHOR]

Nature has evolved numerous supramolecular machineries for modulating various cellular functions. Inspired by the assembly of these sophisticated structures in nature, the controlled assembly of synthetic peptides emerges as a promising approach to therapeutically relevant applications. The self-assembling biomimetic peptides could form well-ordered architectures through non-covalent interactions such as π-π stacking, van der Waals, electrostatic, and hydrogen bonding. In addition, the peptidic building blocks are highly biocompatible and allow facile chemical manipulation with diverse functionalities. For decades, a serious of engineered self-assembling peptides have been extensively studied as functional hydrogels for various applications. Meanwhile, the surface modification strategies based on self-assembling peptide matrices have also raised the attention of biomaterials researchers due to their programmability and 3D porous morphologies. This concise review will cover recent advances in self-assembling peptide matrices as functional coatings for implantable devices. The opportunities and challenges in this field will also be discussed.

Spinal cord regeneration using stem cell transplantation is a promising strategy for regenerative therapy. Stem cells transplanted onto scaffolds that can mimic natural extracellular matrix (ECM) have the potential to significantly improve outcomes. In this study, we strived to develop a cell carrier by culturing neural stem cells (NSCs) onto electrospun 2D and 3D constructs made up of specific crosslinked functionalized self-assembling peptides (SAPs) featuring enhanced biomimetic and biomechanical properties. Morphology, architecture, and secondary structures of electrospun scaffolds in the solid-state and electrospinning solution were studied step by step. Morphological studies showed the benefit of mixed peptides and surfactants as additives to form thinner, uniform, and defect-free fibers. It has been observed that β-sheet conformation as evidence of self-assembling has been predominant throughout the process except for the electrospinning solution. In vitro NSCs seeded on electrospun SAP scaffolds in 2D and 3D conditions displayed desirable proliferation, viability, and differentiation in comparison to the gold standard. In vivo biocompatibility assay confirmed the permissibility of implanted fibrous channels by foreign body reaction. The results of this study demonstrated that fibrous 2D/3D electrospun SAP scaffolds, when shaped as micro-channels, can be suitable to support NSC transplantation for regeneration following spinal cord injury.

Self-assembled peptides possess remarkable potential as targeted drug delivery systems and key applications dwell anti-cancer therapy. Peptides can self-assemble into nanostructures of diverse sizes and shapes in response to changing environmental conditions (pH, temperature, ionic strength). Herein, we investigated the development of self-assembled peptide-based nanofibers (NFs) with the inclusion of a cell-penetrating peptide (namely gH625) and a matrix metalloproteinase-9 (MMP-9) responsive sequence, which proved to enhance respectively the penetration and tumor-triggered cleavage to release Doxorubicin in Triple Negative Breast Cancer cells where MMP-9 levels are elevated. The NFs formulation has been optimized via critical micelle concentration measurements, fluorescence, and circular dichroism. The final nanovectors were characterized for morphology (TEM), size (hydrodynamic diameter), and surface charge (zeta potential). The Doxo loading and release kinetics were studied in situ, by optical microspectroscopy (fluorescence and surface-enhanced Raman scattering–SERS). Confocal spectral imaging of the Doxo fluorescence was used to study the TNBC models in vitro, in cells with various MMP-9 levels, the drug delivery to cells as well as the resulting cytotoxicity profiles. The results confirm that these NFs are a promising platform to develop novel nanovectors of Doxo, namely in the framework of TNBC treatment. [ABSTRACT FROM AUTHOR]

The focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that participates in integrin-mediated signal transduction and contributes to different biological processes, such as cell migration, survival, proliferation and angiogenesis. Moreover, FAK can be activated by autophosphorylation at position Y397 and trigger different signaling pathways in response to increased extracellular matrix stiffness. In addition, FAK is overexpressed and/or hyperactivated in many epithelial cancers, and its expression correlates with tumor malignancy and invasion potential. One of the characteristics of solid tumors is an over deposition of ECM components, which generates a stiff microenvironment that promotes, among other features, sustained cell proliferation and survival. Researchers are, therefore, increasingly developing cell culture models to mimic the increased stiffness associated with these kinds of tumors. In the present work, we have developed a new 3D in vitro model to study the effect of matrix stiffness in pancreatic ductal adenocarcinoma (PDAC) cells as this kind of tumor is characterized by a desmoplastic stroma and an increased stiffness compared to its normal counterpart. For that, we have used a synthetic self-assembling peptide nanofiber matrix, RAD16-I, which does not suffer a significant degradation in vitro, thus allowing to maintain the same local stiffness along culture time. We show that increased matrix stiffness in synthetic 3D RAD16-I gels, but not in collagen type I scaffolds, promotes FAK downregulation at a protein level in all the cell lines analyzed. Moreover, even though it has classically been described that stiff 3D matrices promote an increase in pFAKY397/FAK proteins, we found that this ratio in soft and stiff RAD16-I gels is cell-type-dependent. This study highlights how cell response to increased matrix stiffness greatly depends on the nature of the matrix used for 3D culture. [ABSTRACT FROM AUTHOR]

The burst release of small molecular water-soluble drugs is a major problem when pursuing their long-acting formulations. Although various types of carrier materials have been developed for tackling this problem, it is still a big challenge to prevent water-soluble small molecules from fast release and diffusion. In this study, a biomineralization strategy based upon a self-assembling peptide is proposed for the slow release of lidocaine, a classic anesthetic with high solubility and a very small molecular weight. A bolaamphiphilic peptide was designed to self-assemble and produce negatively charged nanofibers, which were used as the template to absorb positively charged lidocaine molecules through an electrostatic interaction. The biomineralization of lidocaine was then induced by adjusting the pH, which lead to the formation of lidocaine microcrystals with a homogenous size. The microcrystals were incorporated into a hyaluronic acid hydrogel to form an injectable formulation. This formulation slowly released lidocaine and generate a prolonged anesthetic and analgesic effect in rodent models. Due to the constrained local and plasma lidocaine concentration, as well as the biocompatibility and biodegradability of the peptide materials, this formulation also showed considerable safety. These results suggest that nanofiber assisted biomineralization can provide a potential strategy for the fabrication of long-acting formulations for small molecular water-soluble drugs. Long-acting formulations are highly pursued to achieve stronger therapeutic effect, or to avoid repeated administration of drugs, especially through painful injection. Using carrier materials to slow down the release of bioactive molecules is a common strategy to reach this goal. However, for many water-soluble small molecular drugs currently used in clinic, it is notoriously difficult to slow down their release and diffusion. This study proposes a novel strategy based on a controllable mineralization process using self-assembling peptide nanofibers as the template. Taking lidocaine as an example, we showed how peptide-drug microcrystals with well-controlled size and shape could be obtained, which exhibit significantly prolonged anesthetic and analgesic effect. As a proof-of-concept study, this work proposes a promising strategy to control the release of water-soluble small molecular drugs. [Display omitted] [ABSTRACT FROM AUTHOR]

Jing Liu,1,2 Fei Peng,1,2 Yi Kang,1,2 Deying Gong,1,2 Jing Fan,1,2 Wensheng Zhang,1,2 Feng Qiu1,2 1Laboratory of Anesthesia and Critical Care Medicine, Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China; 2National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of ChinaCorrespondence: Feng Qiu; Wensheng Zhang Email fengqiu@scu.edu.cn; zhang_ws@scu.edu.cnPurpose: Typical hydrophobic amino acids (HAAs) are important motifs for self-assembling peptides (SAPs), but they lead to low water-solubility or compact packing of peptides, limiting their capacity for encapsulating hydrophobic drugs. As an alternative, we designed a peptide GQY based on atypical HAAs, which could encapsulate hydrophobic drugs more efficiently. Although hydrophobic general anesthetics (GAs) have been formulated as lipid emulsions, their lipid-free formulations have been pursued because of some side effects inherent to lipids. Using GAs as targets, potential application of GQY as a carrier for hydrophobic drugs was evaluated.Methods: Thioflavin-T (ThT) binding test, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to examine the self-assembling ability of GQY. Pyrene and 8-Anilino-1-naphthalenesulfonic acid (ANS) were used to confirm formation of hydrophobic domain in GQY nanoparticles. Using pyrene as a model, GQY’s capacity to encapsulate hydrophobic drugs was evaluated. GAs including propofol, etomidate and ET26 were encapsulated by GQY. Loss of righting reflex (LORR) test was conducted to assess the anesthetic efficacy of these lipid-free formulations. Paw-licking test was used to evaluate pain-on-injection of propofol-GQY (PROP-GQY) formulation. Hemolytic and cytotoxicity assay were used to evaluate biocompatibility of GQY.Results: Stable nanoparticles containing plenty of hydrophobic cavities could be formed by GQY, which could encapsulate hydrophobic drugs at very high concentration and form stable suspensions. Propofol, etomidate and ET26 formulated by GQY showed anesthetic efficacy comparable to their currently available formulations. Unlike clinic lipid emulsion, PROP-GQY formulation did not cause pain-on-injection in rats. Neither obvious cytotoxicity nor hemolytic activity of GQY was observed.Conclusion: GQY could encapsulate GAs to obtain stable and effective formulations. As a lipid-free carrier, GQY exhibited considerable biocompatibility and other side benefits such as reducing pain-on-injection. More SAPs based on atypical HAAs could be designed as promising carriers for hydrophobic drugs.Keywords: self-assembling peptides, nanoparticles, hydrophobic drugs, lipid-free formulations, general anesthetics

The demands of tissue engineering and regenerative medicine require biomaterials to be accurately deposited into biomimetic shapes, support cellular behaviour and lead to functional tissue formation. Bioinspired yet synthetic biomaterials offer significant advantages over processed, animal-derived products; including high reproducibility and clinical compliance and specific engineered biomimicry of architecture and biological function. Self-assembling peptides are synthetic highly hydrated scaffolds that are rationally designed to mimic the extracellular matrix of a target tissue. Due to the potential benefits of chemically synthesised self-assembling peptides for clinical translation, their development into tools for biofabrication is warranted. However, these systems can be poorly suited to the demands of biofabrication, particularly when functionalised toward tissue-specific conditions. Here, we demonstrate how to improve biofabrication of self-assembling peptides. The fibrillar network arising from the self-assembling peptide Fmoc-FRGDF (containing cell attachment motif RGD) is combined with the robust polysaccharides agarose and alginate demonstrating enhanced printability and cellular compatibility. This study provides a robust methodology for the on-demand printing of personalised implants with a clinically relevant material.

Bioinspired self-assembly is a bottom-up strategy enabling biologically sophisticated nanostructured biogels that can mimic natural tissue. Self-assembling peptides (SAPs), carefully designed, form signal-rich supramolecular nanostructures that intertwine to form a hydrogel material that can be used for a range of cell and tissue engineering scaffolds. Using the tools of nature, they are a versatile framework for the supply and presentation of important biological factors. Recent developments have shown promise for many applications such as therapeutic gene, drug and cell delivery and yet are stable enough for large-scale tissue engineering. This is due to their excellent programmability—features can be incorporated for innate biocompatibility, biodegradability, synthetic feasibility, biological functionality and responsiveness to external stimuli. SAPs can be used independently or combined with other (macro)molecules to recapitulate surprisingly complex biological functions in a simple framework. It is easy to accomplish localized delivery, since they can be injected and can deliver targeted and sustained effects. In this review, we discuss the categories of SAPs, applications for gene and drug delivery, and their inherent design challenges. We highlight selected applications from the literature and make suggestions to advance the field with SAPs as a simple, yet smart delivery platform for emerging BioMedTech applications.

To compare the effectiveness of self-assembling peptides (SAP) P 11 -4 in remineralising early enamel lesions to that of other remineralising agents. This review was conducted according to PRISMA guidelines. MEDLINE (PubMed), Cochrane and Google Scholar databases were searched up to June 2021. For qualitative analysis, randomised controlled trials and in-vitro investigations were included. For quantitative synthesis, randomised controlled trials with comparable outcomes were used. The risk of bias assessment and meta-analysis were carried out using the RoB 2 tool and RevMan software. This systematic review and meta-analysis included a total of 12 in-vitro studies and 6 randomised controlled trials. SAP P 11 -4 had superior effect in remineralising early enamel lesions compared to control groups. In Meta-analysis, SAP P 11 -4 showed superior remineralization when measured using the VAS data {SMD [-0.61 (−0.88, −0.34)]}; significant caries regression according to Nyvad criteria {OR [0.16(0.03,0.88)]}; and significant improvement in the extent of demineralization in test group {SMD [-0.67 (−1.29, −0.05)]} when measured for fluorescence in comparison with other remineralising agents. On the other hand, morphometric measurements {MD [-0.12(-0.25, −0.00)]} and ICDAS criteria {OR [4.91(0.80, 30.22)]} found no difference among the tested materials. Both in-vitro and in-vivo studies showed evidence of superior biomimetic remineralization in the SAP P 11 -4 group compared to other remineralising agents. However, long term studies are necessary to confirm its suitability in clinical use. [Display omitted] [ABSTRACT FROM AUTHOR]

Wound healing is a long‐term, multistage biological process that includes hemostasis, inflammation, proliferation, and tissue remodeling and requires intelligent designs to provide comprehensive and convenient treatment. The complexity of wounds has led to a lack of adequate wound treatment materials, which must systematically regulate unique wound microenvironments. Hydrogels have significant advantages in wound treatment due to their ability to provide spatiotemporal control over the wound healing process. Self‐assembling peptide‐based hydrogels are particularly attractive due to their innate biocompatibility and biodegradability along with additional advantages including ligand‐receptor recognition, stimulus‐responsive self‐assembly, and the ability to mimic the extracellular matrix. The ability of peptide‐based materials to self‐assemble in response to the physiological environment, resulting in functionalized microscopic structures, makes them conducive to wound treatment. This review introduces several self‐assembling peptide‐based systems with various advantages and emphasizes recent advances in self‐assembling peptide‐based hydrogels that allow for precise control during different stages of wound healing. Moreover, the development of multifunctional self‐assembling peptide‐based hydrogels that can regulate and remodel the wound immune microenvironment in wound therapy with spatiotemporal control has also been summarized. Overall, this review sheds light on the future clinical and practical applications of self‐assembling peptide‐based hydrogels. [ABSTRACT FROM AUTHOR]

One of the most desirable properties that biomaterials designed for tissue engineering or drug delivery applications should fulfill is biodegradation and resorption without toxicity. Therefore, there is an increasing interest in the development of biomaterials able to be enzymatically degraded once implanted at the injury site or once delivered to the target organ. In this paper, we demonstrate the protease sensitivity of self-assembling amphiphilic peptides, in particular, RAD16-I (AcN-RADARADARADARADA-CONH2), which contains four potential cleavage sites for trypsin. We detected that when subjected to thermal denaturation, the peptide secondary structure suffers a transition from β-sheet to random coil. We also used Matrix-Assisted Laser Desorption/Ionization-Time-Of-Flight (MALDI-TOF) to detect the proteolytic breakdown products of samples subjected to incubation with trypsin as well as atomic force microscopy (AFM) to visualize the effect of the degradation on the nanofiber scaffold. Interestingly, thermally treated samples had a higher extent of degradation than non-denatured samples, suggesting that the transition from β-sheet to random coil leaves the cleavage sites accessible and susceptible to protease degradation. These results indicate that the self-assembling peptide can be reduced to short peptide sequences and, subsequently, degraded to single amino acids, constituting a group of naturally biodegradable materials optimal for their application in tissue engineering and regenerative medicine. [ABSTRACT FROM AUTHOR]

Wet adhesion technology has potential applications in various fields, especially in the biomedical field, yet it has not been completely mastered by humans. Many aquatic organisms (e.g., mussels, sandcastle worms, and barnacles) have evolved into wet adhesion specialists with excellent underwater adhesion abilities, and mimicking their adhesion principles to engineer artificial adhesive materials offers an important avenue to address the wet adhesion issue. The crustacean barnacle secretes a proteinaceous adhesive called barnacle cement, with which they firmly attach their bodies to almost any substrate underwater. Owing to the unique chemical composition, structural property, and adhesion mechanism, barnacle cement has attracted widespread research interest as a novel model for designing biomimetic adhesive materials, with significant progress being made. To further boost the development of barnacle cement–inspired adhesive materials (BCIAMs), it is necessary to systematically summarize their design strategies and research advances. However, no relevant reviews have been published yet. In this context, we presented a systematic review for the first time. First, we introduced the underwater adhesion principles of natural barnacle cement, which lay the basis for the design of BCIAMs. Subsequently, we classified the BCIAMs into three major categories according to the different design strategies and summarized their research advances in great detail. Finally, we discussed the research challenge and future trends of this field. We believe that this review can not only improve our understanding of the molecular mechanism of barnacle underwater adhesion but also accelerate the development of barnacle-inspired wet adhesion technology.

Abstract Wound healing is a long‐term, multistage biological process that includes hemostasis, inflammation, proliferation, and tissue remodeling and requires intelligent designs to provide comprehensive and convenient treatment. The complexity of wounds has led to a lack of adequate wound treatment materials, which must systematically regulate unique wound microenvironments. Hydrogels have significant advantages in wound treatment due to their ability to provide spatiotemporal control over the wound healing process. Self‐assembling peptide‐based hydrogels are particularly attractive due to their innate biocompatibility and biodegradability along with additional advantages including ligand‐receptor recognition, stimulus‐responsive self‐assembly, and the ability to mimic the extracellular matrix. The ability of peptide‐based materials to self‐assemble in response to the physiological environment, resulting in functionalized microscopic structures, makes them conducive to wound treatment. This review introduces several self‐assembling peptide‐based systems with various advantages and emphasizes recent advances in self‐assembling peptide‐based hydrogels that allow for precise control during different stages of wound healing. Moreover, the development of multifunctional self‐assembling peptide‐based hydrogels that can regulate and remodel the wound immune microenvironment in wound therapy with spatiotemporal control has also been summarized. Overall, this review sheds light on the future clinical and practical applications of self‐assembling peptide‐based hydrogels.

Abstract Background Self‐assembling peptides (TDMs) comprise synthetic amphipathic peptides that immediately react to changes in pH and/or inorganic salts to transform into a gelatinous state. The first generation of these peptides (TDM‐621) is currently used as a hemostatic agent in Europe. However, TDM‐621 exhibits slow gel‐formation and low retention capabilities on tissue surfaces. The second generation (TDM‐623) was therefore developed to encourage faster gel‐formation and better tissue‐sealing capabilities. Aim The aim of this study was to verify the efficacy of TDM‐623 in terms of its hemostatic effect in endoscopic surgery. Materials and methods Evaluation of the hemostatic effect in endoscopic surgery (animal study) was performed using eight porcine in spine position. Following systemic heparinization, we established a “bleeding model” by endoscopic grasping forceps on the anterior walls of the stomach and duodenum. In the hemostasis method, an endoscope with a distal hood was brought into contact with the bleeding point, and 1 ml TDM‐623 was applied to the wound. After TDM‐623 gelation, the endoscope was removed, and the acute hemostatic effect (after 2 min) was confirmed. Result In the endoscopic bleeding model, 17 of the 23 cases (74%) showed complete hemostatic effects on the anterior wall of the stomach, and 18 of the 20 cases (80%) on the anterior wall of the duodenum, respectively. None of the applied gels were displaced from the anterior walls of the stomach and duodenum. Conclusion The new self‐assembling peptide (TDM‐623) showed high hemostatic effects. TDM‐623 had potential usefulness for upper gastrointestinal endoscopic surgery.

Objectives: To evaluate self-assembling peptides (SAP) for caries prevention and arrest in primary tooth enamel in vitro. Materials and Methods: Overall, 180 extracted primary teeth were used. In the prevention experiment (n = 20 samples per group), self-assembling peptide for prevention (SAPP), fluoride varnish/mouthwash (FV/FMW), casein-phosphopeptide amorphous-calcium phosphate (CPP-ACP), and nanohydroxyapatite (nHA) were applied. Samples were subjected to a demineralizing pH cycling for 14 days. In the arrest experiment (n = 15/group), 60 samples were pre-demineralized; induced lesions were treated using self-assembling peptide for repair (SAPR), FV, CPP-ACP plus fluoride, and resin infiltration (RI) and submitted to pH cycling. Mineral loss and its differences as well as lesion depth were determined using transversal microradiography. Numerical data were tested for normality using Shapiro–Wilk's test and were compared using Kruskal–Wallis test followed by pairwise comparisons utilizing multiple Mann–Whitney U tests with Bonferroni correction. The significance level was set at P < 0.05 within all tests. Results: FV (median: −46.3 [interquartile range: 175.52] vol% × µm) and FMW (−33.35 [124.65] vol% × µm) prevented caries significantly more effectively than all other groups (P < 0.001), which did not show significant preventive effects. RI (median: 4949.70 [1637.20] vol% × µm) and FV (median = 6076.05 [5190.08] vol% × µm) arrested lesions, whereas SAPR and CPP-ACPF did not show such arrest. Conclusions: FV and FMW showed the largest caries-preventive effect, whereas RI and FV arrested lesion progression in primary tooth enamel in vitro. [ABSTRACT FROM AUTHOR]

Anastomotic bleeding in vascular surgery can be difficult to control. Patients, in particular those undergoing carotid surgery, have often been started on treatment with dual antiplatelet agents and receive systemic heparinization intraoperatively. The use of local hemostatic agents as an adjunct to conventional methods is widely reported. 3-D Matrix's absorbable hemostatic material RADA16 (PuraStat®), is a fully synthetic resorbable hemostatic agent. The aim of this study is to confirm the safety and performance of this agent when used to control intraoperative anastomotic bleeding during carotid endarterectomy (CEA). A prospective, single-arm, multicenter study involving 65 patients, undergoing CEA, in whom the hemostatic agent was applied to the suture line after removal of arterial clamps. Patients were followed up at 24 h, discharge, and one month after surgery. Time to hemostasis was measured as the primary endpoint. Secondary endpoints included hemostasis efficacy and safety outcomes, blood loss, intraoperative and postoperative administration of blood products, and incidence of reoperation for bleeding. A total of 65 cases (51 male and 14 female) undergoing CEA, utilizing patch reconstruction (90. 8%), eversion technique (6.1%), and direct closure (3.1%) were analyzed. All patients received dual antiplatelet therapy preoperatively and were administered systemic intravenous heparin intraoperatively, as per local protocol. The mean time to hemostasis was 83 s ± 105 s (95% CI: 55-110 s). Primary hemostatic efficacy was 90.8%. The mean volume of product used was 1.7 mL ± 1.1 mL. Hemostasis was achieved with a single application of the product in 49 patients (75.3%). Two patients required a transfusion of blood products intraoperatively. There were no blood product transfusions during the postoperative period. The intraoperative mean blood loss was 127 mL ± 111.4 mL and postoperatively, the total mean drainage volume was 49.0 mL ± 51.2 mL. The mean duration of surgery was 119 ± 35 min, and the mean clamp time was 35 min 12 s ± 19 min 59 s. In 90.8% of patients, there was no presence of hematoma at 24 h postoperatively. Three returned to theatre due to bleeding (2 in the first 24 h), however, none of these cases were considered product related. Overall, there were no device-related serious adverse events (SAE) or unanticipated device-related SAEs reported. Use of the hemostatic agent PuraStat® is associated with a high rate of hemostatic efficacy (90.8%) and a short time to hemostasis. The safety of the product for use on vascular anastomoses has been demonstrated. [ABSTRACT FROM AUTHOR]

[Display omitted] Guiding neuronal cell growth is desirable for neural tissue engineering but is very challenging. In this work, a self-assembling ultra-short surfactant-like peptide I 3 K which possesses positively charged lysine head groups, and hydrophobic isoleucine tails, was chosen to investigate its potential for guiding neuronal cell growth. The peptides were able to self-assemble into nanofibrous structures and interact strongly with silk fibroin (SF) scaffolds, providing a niche for neural cell attachment and proliferation. SF is an excellent biomaterial for tissue engineering. However neuronal cells, such as rat PC12 cells, showed poor attachment on pure regenerated SF (RSF) scaffold surfaces. Patterning of I 3 K peptide nanofibers on RSF surfaces significantly improved cellular attachment, cellular density, as well as morphology of PC12 cells. The live / dead assay confirmed that RSF and I 3 K have negligible cytotoxicity against PC12 cells. Atomic force microscopy (AFM) was used to image the topography and neurite formation of PC12 cells, where results revealed that self-assembled I 3 K nanofibers can support the formation of PC12 cell neurites. Immunolabelling also demonstrated that coating of I 3 K nanofibers onto the RSF surfaces not only increased the percentage of cells bearing neurites but also increased the average maximum neurite length. Therefore, the peptide I 3 K could be used as an alternative to poly- l -lysine for cell culture and tissue engineering applications. As micro-patterning of neural cells to guide neurite growth is important for developing nerve tissue engineering scaffolds, inkjet printing was used to pattern self-assembled I 3 K peptide nanofibers on RSF surfaces for directional control of PC12 cell growth. The results demonstrated that inkjet-printed peptide micro-patterns can effectively guide the cell alignment and organization on RSF scaffold surfaces, providing great potential for nerve regeneration applications. [ABSTRACT FROM AUTHOR]

Kun Xia,1,2,* Zhuo Chen,3,4,* Jie Chen,1 Huaxing Xu,1 Yunfei Xu,1 Ting Yang,1 Qi Zhang1 1Department of Endodontics, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, People’s Republic of China; 2Department of Preventive Dentistry, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou 325027, People’s Republic of China; 3Department of Endodontics, The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou 310006, People’s Republic of China; 4Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou 310006, People’s Republic of China*These authors contributed equally to this workCorrespondence: Qi ZhangDepartment of Endodontics, School and Hospital of Stomatology, Tongji University, Shanghai, Engineering Research Center of Tooth Restoration and Regeneration, Yanchang Road 399, Shanghai 200072, People’s Republic of ChinaTel +86-21-66311659Fax +86-21-66524025Email qizhang@tongji.edu.cnIntroduction: Cell-based tissue engineering is a promising method for dentin-pulp complex (DPC) regeneration. The challenges associated with DPC regeneration include the generation of a suitable microenvironment that facilitates the complete odontogenic differentiation of dental pulp stem cells (DPSCs) and the rapid induction of angiogenesis. Thus, the survival and subsequent differentiation of DPSCs are limited. Extracellular matrix (ECM)-like biomimetic hydrogels composed of self-assembling peptides (SAPs) were developed to provide an appropriate microenvironment for DPSCs. For functional DPC regeneration, the most important considerations are to provide an environment that promotes the adequate attachment of DPSCs and rapid vascularization of the regenerating pulp. Morphogenic signals in the form of growth factors (GFs) have been incorporated into SAPs to promote productive DPSC behaviors. However, the use of GFs has several drawbacks. We envision using a scaffold with SAPs coupled with long-term factors to increase DPSC attachment and vascularization as a method to address this challenge.Methods: In this study, we developed synthetic material for an SAP-based scaffold with RGD- and vascular endothelial growth factor (VEGF)-mimetic peptide epitopes with the dual functions of dentin and pulp regeneration. DPSCs and human umbilical vein endothelial cells (HUVECs) were used to evaluate the biological effects of SAP-based scaffolds. Furthermore, the pulpotomized molar rat model was employed to test the reparative and regenerative effects of SAP-based scaffolds.Results: This scaffold simultaneously presented RGD- and VEGF-mimetic peptide epitopes and provided a 3D microenvironment for DPSCs. DPSCs grown on this composite scaffold exhibited significantly improved survival and angiogenic and odontogenic differentiation in the multifunctionalized group in vitro. Histological and functional evaluations of a partially pulpotomized rat model revealed that the multifunctionalized scaffold was superior to other options with respect to stimulating pulp recovery and dentin regeneration in vivo.Conclusion: Based on our data obtained with the functionalized SAP scaffold, a 3D microenvironment that supports stem cell adhesion and angiogenesis was generated that has great potential for dental pulp tissue engineering and regeneration.Keywords: dentin-pulp complex regeneration, dental pulp stem cells, self-assembling peptides, cell adhesion, angiogenesis, multifunctionalization

Organ fabrication as the solution to renewable donor demands requires the ability to spatially deposit viable cells into biologically relevant constructs; necessitating reliable and effective cell deposition through bioprinting and the subsequent ability to mature. However, effective bioink development demands advances in both printability and control of cellular response. Effective bioinks are designed to retain shape fidelity, influence cellular behavior, having bioactive morphologies stiffness and highly hydrated environment. Hybrid hydrogels are promising candidates as they reduce the need to re‐engineer materials for tissue‐specific properties, with each component offering beneficial properties. Herein, a multicomponent bioink is developed whereby gelatin methacrylate (GelMA) and fluorenylmethoxycarbonyprotected self‐assembling peptides (Fmoc‐SAPs) undergo coassembly to yield a tuneable bioink. This study shows that the reported fibronectin‐inspired fmoc‐SAPs present cell attachment epitopes RGD and PHSRN in the form of bioactive nanofibers; and that the GelMA enables superior printability, stability in media, and controlled mechanical properties. Importantly, when in the hybrid format, no disruption to either the methacrylate crosslinking of GelMA, or self‐assembled peptide fibril formation is observed. Finally, studies with primary myoblasts show over 98% viability at 72 h and differentiation into fused myotubes at one and two weeks demonstrate the utility of the material as a functional bioink for muscle engineering.

Peptide-based hydrogels are of great interest in the biomedical field according to their biocompatibility, simple structure and tunable properties via sequence modification. In recent years, multicomponent assembly of peptides have expanded the possibilities to produce more versatile hydrogels, by blending gelating peptides with different type of peptides to add new features. In the present study, the assembly of gelating P5 peptide SFFSF blended with P21 peptide, SFFSFGVPGVGVPGVGSFFSF, an elastin-inspired peptides or, alternatively, with FF dipeptide, was investigated by oscillatory rheology and different microscopy techniques in order to shed light on the nanotopologies formed by the self-assembled peptide mixtures. Our data show that, depending on the added peptides, cooperative or disruptive assembly can be observed giving rise to distinct nanotopologies to which correspond different mechanical properties that could be exploited to fabricate materials with desired properties.

Oxidized polyvinyl alcohol (OxPVA) is a new polymer for the fabrication of nerve conduits (NCs). Looking for OxPVA device optimization and coupling it with a natural sheath may boost bioactivity. Thus, OxPVA/chitosan sponges (ChS) as hybrid scaffolds were investigated to predict in the vivo behaviour of two-layered NCs. To encourage interaction with cells, ChS were functionalized with the self-assembling-peptide (SAP) EAK, without/with the laminin-derived sequences -IKVAV/-YIGSR. Thus, ChS and the hybrid scaffolds were characterized for mechanical properties, ultrastructure (Scanning Electron Microscopy, SEM), bioactivity, and biocompatibility. Regarding mechanical analysis, the peptide-free ChS showed the highest values of compressive modulus and maximum stress. However, among +EAK groups, ChS+EAK showed a significantly higher maximum stress than that found for ChS+EAK-IKVAV and ChS+EAK-YIGSR. Considering ultrastructure, microporous interconnections were tighter in both the OxPVA/ChS and +EAK groups than in the others; all the scaffolds induced SH-SY5Y cells’ adhesion/proliferation, with significant differences from day 7 and a higher total cell number for OxPVA/ChS+EAK scaffolds, in accordance with SEM. The scaffolds elicited only a slight inflammation after 14 days of subcutaneous implantation in Balb/c mice, proving biocompatibility. ChS porosity, EAK 3D features and neuro-friendly attitude (shared with IKVAV/YIGSR motifs) may confer to OxPVA certain bioactivity, laying the basis for future appealing NCs.

Glioblastoma multiforme (GBM) is the most aggressive central nervous system tumor, and standard treatment, including surgical resection, radiation, and chemotherapy, has not significantly improved patient outcomes over the last 20 years. Temozolomide (TMZ), the prodrug most commonly used to treat GBM, must pass the blood–brain barrier and requires a basic pH to convert to its active form. Due to these barriers, less than 30% of orally delivered TMZ reaches the central nervous system and becomes bioactive. In this work, we have developed a novel biomaterial delivery system to convert TMZ to its active form and that shows promise for intracellular TMZ delivery. Self-assembling peptides were characterized under several different assembly conditions and evaluated for TMZ loading and conversion. Both solvent and method of assembly were found to affect the supramolecular and secondary structure of peptide assemblies. Additionally, as peptides degraded in phosphate-buffered saline, TMZ was rapidly converted to its active form. This work demonstrates that peptide-based drug delivery systems can effectively create a local stimulus during drug delivery while remaining biocompatible. This principle could be used in many future biomedical applications in addition to cancer treatment, such as wound healing and regenerative medicine.

Peptides as unique supramolecular nanofibrous materials are favored choices to fabricate hydrogel for artificial extracellular matrices. Herein, we devised an amphiphilic polypeptide that could be motivated by multiple substances with positively charged group at physiological temperature and pH to assemble supramolecular nanofiber hydrogels since the electrostatic repulsion between monomers was attenuated. The hydrogelation phenomenon and spectroscopy were compatible with molecular dynamics simulations (MDs) results for revealing the assembly mechanism of this peptide, confirming that the behavior of assembling and the typical secondary structure of the assemblies was β -sheet. The impact of peptide concentration on the mechanical properties of hydrogels were described using rheology. We found that the peptide formed elastic gels from 0.3 wt% onwards in practical use and that these recovered by themselves after shear thinning that indicated they were injectable hydrogels. The successful establishment of cell spheres with high cell viability during 15 days culture in 3D space demonstrated the nanofiber hydrogels had potential in cell model construction and microtissue culture. Overall, the superior biologically friendly gel-forming conditions and excellent biological properties of this supramolecular assembly peptide material have invigorated the progress of biomedical fields such as tissue regeneration based on in vitro 3D culture. [Display omitted] [ABSTRACT FROM AUTHOR]

The focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that participates in integrin-mediated signal transduction and contributes to different biological processes, such as cell migration, survival, proliferation and angiogenesis. Moreover, FAK can be activated by autophosphorylation at position Y397 and trigger different signaling pathways in response to increased extracellular matrix stiffness. In addition, FAK is overexpressed and/or hyperactivated in many epithelial cancers, and its expression correlates with tumor malignancy and invasion potential. One of the characteristics of solid tumors is an over deposition of ECM components, which generates a stiff microenvironment that promotes, among other features, sustained cell proliferation and survival. Researchers are, therefore, increasingly developing cell culture models to mimic the increased stiffness associated with these kinds of tumors. In the present work, we have developed a new 3D in vitro model to study the effect of matrix stiffness in pancreatic ductal adenocarcinoma (PDAC) cells as this kind of tumor is characterized by a desmoplastic stroma and an increased stiffness compared to its normal counterpart. For that, we have used a synthetic self-assembling peptide nanofiber matrix, RAD16-I, which does not suffer a significant degradation in vitro, thus allowing to maintain the same local stiffness along culture time. We show that increased matrix stiffness in synthetic 3D RAD16-I gels, but not in collagen type I scaffolds, promotes FAK downregulation at a protein level in all the cell lines analyzed. Moreover, even though it has classically been described that stiff 3D matrices promote an increase in pFAKY397/FAK proteins, we found that this ratio in soft and stiff RAD16-I gels is cell-type-dependent. This study highlights how cell response to increased matrix stiffness greatly depends on the nature of the matrix used for 3D culture.

Self-assembled peptides possess remarkable potential as targeted drug delivery systems and key applications dwell anti-cancer therapy. Peptides can self-assemble into nanostructures of diverse sizes and shapes in response to changing environmental conditions (pH, temperature, ionic strength). Herein, we investigated the development of self-assembled peptide-based nanofibers (NFs) with the inclusion of a cell-penetrating peptide (namely gH625) and a matrix metalloproteinase-9 (MMP-9) responsive sequence, which proved to enhance respectively the penetration and tumor-triggered cleavage to release Doxorubicin in Triple Negative Breast Cancer cells where MMP-9 levels are elevated. The NFs formulation has been optimized via critical micelle concentration measurements, fluorescence, and circular dichroism. The final nanovectors were characterized for morphology (TEM), size (hydrodynamic diameter), and surface charge (zeta potential). The Doxo loading and release kinetics were studied in situ, by optical microspectroscopy (fluorescence and surface-enhanced Raman scattering–SERS). Confocal spectral imaging of the Doxo fluorescence was used to study the TNBC models in vitro, in cells with various MMP-9 levels, the drug delivery to cells as well as the resulting cytotoxicity profiles. The results confirm that these NFs are a promising platform to develop novel nanovectors of Doxo, namely in the framework of TNBC treatment.

One of the most desirable properties that biomaterials designed for tissue engineering or drug delivery applications should fulfill is biodegradation and resorption without toxicity. Therefore, there is an increasing interest in the development of biomaterials able to be enzymatically degraded once implanted at the injury site or once delivered to the target organ. In this paper, we demonstrate the protease sensitivity of self-assembling amphiphilic peptides, in particular, RAD16-I (AcN-RADARADARADARADA-CONH2), which contains four potential cleavage sites for trypsin. We detected that when subjected to thermal denaturation, the peptide secondary structure suffers a transition from β-sheet to random coil. We also used Matrix-Assisted Laser Desorption/Ionization-Time-Of-Flight (MALDI-TOF) to detect the proteolytic breakdown products of samples subjected to incubation with trypsin as well as atomic force microscopy (AFM) to visualize the effect of the degradation on the nanofiber scaffold. Interestingly, thermally treated samples had a higher extent of degradation than non-denatured samples, suggesting that the transition from β-sheet to random coil leaves the cleavage sites accessible and susceptible to protease degradation. These results indicate that the self-assembling peptide can be reduced to short peptide sequences and, subsequently, degraded to single amino acids, constituting a group of naturally biodegradable materials optimal for their application in tissue engineering and regenerative medicine.