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This article explores the emerging field of nanomedicine as a drug delivery system, aimed at enhancing the therapeutic efficacy of active pharmaceutical ingredients in medicinal plants. The traditional methods of applying medicinal plants present several limitations, such as low bioavailability, poor solubility, challenges in accurately controlling drug dosage, and inadequate targeting. Nanoformulations represent an innovative approach in drug preparation that employs nanotechnology to produce nanoscale particles or carriers, which are designed to overcome these limitations. Nanoformulations offer distinct advantages, significantly enhancing the solubility and bioavailability of drugs, particularly for the poorly soluble components of medicinal plants. These formulations effectively enhance solubility, thereby facilitating better absorption and utilization by the human body, which in turn improves drug efficacy. Furthermore, nanomedicine enables targeted drug delivery, ensuring precise administration to the lesion site and minimizing side effects on healthy tissues. Additionally, nanoformulations can regulate drug release rates, extend the duration of therapeutic action, and enhance the stability of treatment effects. However, nanoformulations present certain limitations and potential risks; their stability and safety require further investigation, particularly regarding the potential toxicity with long-term use. Nevertheless, nanomaterials demonstrate substantial potential in augmenting the efficacy of active pharmaceutical ingredients in medicinal plants, offering novel approaches and methodologies for their development and application. [ABSTRACT FROM AUTHOR]

The consequences of intramolecular ionic interactions in determining the reactivity of functional groups are of interest because they provide insights into how nature deploys seemingly reactive functionalities to be rather ubiquitous. Of specific interest are the quaternary ammonium ions in lipids. In this work, we investigate the effect of intramolecular electrostatic interactions in zwitterionic functionalities by judiciously incorporating them as leaving groups at the α‐position of α,β‐unsaturated ester‐based lipid head groups. We find that electrostatic stabilization indeed plays a critical role in both the reaction kinetics with nucleophiles and the thermodynamics of lipid formation. We further leverage these findings to fabricate both triggerable assembly and disassembly of liposomal supramolecular assemblies in the presence of nucleophiles. [ABSTRACT FROM AUTHOR]

This article explores the emerging field of nanomedicine as a drug delivery system, aimed at enhancing the therapeutic efficacy of active pharmaceutical ingredients in medicinal plants. The traditional methods of applying medicinal plants present several limitations, such as low bioavailability, poor solubility, challenges in accurately controlling drug dosage, and inadequate targeting. Nanoformulations represent an innovative approach in drug preparation that employs nanotechnology to produce nanoscale particles or carriers, which are designed to overcome these limitations. Nanoformulations offer distinct advantages, significantly enhancing the solubility and bioavailability of drugs, particularly for the poorly soluble components of medicinal plants. These formulations effectively enhance solubility, thereby facilitating better absorption and utilization by the human body, which in turn improves drug efficacy. Furthermore, nanomedicine enables targeted drug delivery, ensuring precise administration to the lesion site and minimizing side effects on healthy tissues. Additionally, nanoformulations can regulate drug release rates, extend the duration of therapeutic action, and enhance the stability of treatment effects. However, nanoformulations present certain limitations and potential risks; their stability and safety require further investigation, particularly regarding the potential toxicity with long-term use. Nevertheless, nanomaterials demonstrate substantial potential in augmenting the efficacy of active pharmaceutical ingredients in medicinal plants, offering novel approaches and methodologies for their development and application.

Triggerable coatings, such as pH-responsive polymethacrylate copolymers, can be used to protect the active pharmaceutical ingredients contained within oral solid dosage forms from the acidic gastric environment and to facilitate drug delivery directly to the intestine. However, gastrointestinal pH can be highly variable, which can reduce delivery efficiency when using pH-responsive drug delivery technologies. We hypothesized that biomaterials susceptible to proteolysis could be used in combination with other triggerable polymers to develop novel enteric coatings. Bioinformatic analysis suggested that silk fibroin is selectively degradable by enzymes in the small intestine, including chymotrypsin, but resilient to gastric pepsin. Based on the analysis, we developed a silk fibroin-polymethacrylate copolymer coating for oral dosage forms. In vitro and in vivo studies demonstrated that capsules coated with this novel silk fibroin formulation enable pancreatin-dependent drug release. We believe that this novel formulation and extensions thereof have the potential to produce more effective and personalized oral drug delivery systems for vulnerable populations including patients that have impaired and highly variable intestinal physiology. [ABSTRACT FROM AUTHOR]

The development of new approaches for the treatment of the increasingly antibiotic-resistant pathogen Pseudomonas aeruginosa was targeted by enhancing the effect of local antimicrobial photodynamic therapy (aPDT) using poly(ethylene glycol)-block-poly(lactic acid) (PEG114-block-PLAx) nanocarriers that were loaded with a ruthenium-based photosensitizer (PS). The action of tris(1,10-phenanthroline) ruthenium (II) bis(hexafluorophosphate) (RuPhen3) encapsulated in PEG114-block-PLAx micelles and vesicles was shown to result in an appreciable aPDT inactivation efficiency against planktonic Pseudomonas aeruginosa. In particular, the encapsulation of the PS, its release, and the efficiency of singlet oxygen (1O2) generation upon irradiation with blue light were studied spectroscopically. The antimicrobial effect was analyzed with two strains of Pseudomonas aeruginosa. Compared with PS-loaded micelles, formulations of the PS-loaded vesicles showed 10 times enhanced activity with a strong photodynamic inactivation effect of at least a 4.7 log reduction against both a Pseudomonas aeruginosa lab strain and a clinical isolate collected from the lung of a cystic fibrosis (CF) patient. This work lays the foundation for the targeted eradication of Pseudomonas aeruginosa using aPDT in various medical application areas. [ABSTRACT FROM AUTHOR]

A novel approach to surface modification, which consists of the adsorption of microgel–enzyme complexes preformed in solution, is highlighted. Accordingly, the microgel–enzyme complexes were formed due to the electrostatic interaction of the oppositely charged interacting components, that is, a cationic poly(N-isopropylacrylamide)-based microgel and glucose oxidase taken as a model enzyme. The spontaneous adsorption of the prepared microgel–enzyme complexes, examined by means of quartz crystal microbalance with dissipation monitoring and atomic force microscopy, was observed, resulting in the formation of well-adhered microgel–enzyme coatings. Further, the preformed microgel–enzyme complexes were adsorbed onto the modified graphite-based screen-printed electrodes, and their enzymatic responses were determined by means of amperometry, demonstrating a remarkable analytical performance toward the quantification of β-D-glucose in terms of high sensitivity (0.0162 A × M−1 × cm−2), a low limit of detection (1 μM), and an expanded linear range (1–2000 μM). The fabricated microgel–enzyme biosensor constructs were found to be very stable against manifold-repeated measurements. Finally, the pH- or salt-induced release of glucose oxidase from the adsorbed preformed microgel–enzyme complexes was demonstrated. The findings obtained for the microgel–enzyme coatings prepared via adsorption of the preformed microgel–enzyme complexes were compared to those found for the microgel–enzyme coatings fabricated via a previously exploited two-stage sequential adsorption, which includes the adsorption of the microgel first, followed by the electrostatic binding of glucose oxidase by the adsorbed microgel. [ABSTRACT FROM AUTHOR]

Introduction: In targeted enzyme prodrug constructs, it is critical to control the bioactivity of the drug in its prodrug form. The preparation of such constructs often involves conjugation reactions directed to functional groups on amino acid side chains of the protein, which result in random conjugation and incomplete control of bioactivity of a prodrug, which may result in significant nontarget effect. Thus, more specific method of modification is desired. If the drug is a glycoprotein, enzymatic oxidation may offer an alternative approach for therapeutic glycoproteins. Methods: Tissue plasminogen activator (tPA), a model glycoprotein enzyme, was treated with galactose oxidase (GO) and horseradish peroxidase, followed by thiolation reaction and conjugation with low molecular weight heparin (LMWH). The LMWH-tPA conjugate was isolated by ion-exchange chromatography followed by centrifugal filtration. The conjugate was characterized for its fibrinolytic activity and for its plasminogen activation through an indirect amidolytic assay with a plasmin-specific substrate S-2251 when LMWH-tPA conjugate is complexed with protamine-albumin conjugate, followed by triggered activation in the presence of heparin. Results: LMWH-tPA conjugate prepared via enzymatic oxidation retained ~95% of its fibrinolytic activity with respect to native tPA. Upon complexation with protamine-albumin conjugate, the activity of LMWH-tPA was effectively inhibited (~90%) whereas the LMWH-tPA prepared by random thiolation exhibited ~55% inhibition. Addition of heparin fully generated the activities of both conjugates. Conclusion: The tPA was successfully modified via enzymatic oxidation by GO, resulting in enhanced control of its activity in the prodrug construct. This approach can be applied to other therapeutic glycoproteins.

The use of pH-responsive polymeric micelles is a promising approach to afford the targeted, pH-mediated delivery of hydrophobic drugs within the low-pH tumour milieu and intracellular organelles of cancer cells. However, even for a common pH-responsive polymeric micelle system—e.g., those utilising poly(ethylene glycol)-b-poly(2-vinylpyridine) (PEG-b-PVP) diblock copolymers—there is a lack of available data describing the compatibility of hydrophobic drugs, as well as the relationships between copolymer microstructure and drug compatibility. Furthermore, synthesis of the constituent pH-responsive copolymers generally requires complex temperature control or degassing procedures that limit their accessibility. Herein we report the facile synthesis of a series of diblock copolymers via visible-light-mediated photocontrolled reversible addition-fragmentation chain-transfer polymerisation, with a constant PEG block length (90 repeat units (RUs)) and varying PVP block lengths (46–235 RUs). All copolymers exhibited narrow dispersity values (Đ ≤ 1.23) and formed polymeric micelles with low polydispersity index (PDI) values (typically <0.20) at physiological pH (7.4), within a suitable size range for passive tumour targeting (<130 nm). The encapsulation and release of three hydrophobic drugs (cyclin-dependent kinase inhibitor (CDKI)-73, gossypol, and doxorubicin) were investigated in vitro at pH 7.4–4.5 to simulate drug release within the tumour milieu and cancer cell endosome. Marked differences in drug encapsulation and release were observed when the PVP block length was increased from 86 to 235 RUs. With a PVP block length of 235 RUs, the micelles exhibited differing encapsulation and release properties for each drug. Minimal release was observed for doxorubicin (10%, pH 4.5) and CDKI-73 exhibited moderate release (77%, pH 4.5), whereas gossypol exhibited the best combination of encapsulation efficiency (83%) and release (91% pH 4.5) overall. These data demonstrate the drug selectivity of the PVP core, where both the block molecular weight and hydrophobicity of the core (and accordingly the hydrophobicity of the drug) have a significant effect on drug encapsulation and release. These systems remain a promising means of achieving targeted, pH-responsive drug delivery—albeit for select, compatible hydrophobic drugs—which warrants their further investigation to develop and evaluate clinically relevant micelle systems. [ABSTRACT FROM AUTHOR]

Melanoma is the most aggressive and metastasis-prone form of skin cancer. Conventional therapies include chemotherapeutic agents, either as small molecules or carried by FDA-approved nanostructures. However, systemic toxicity and side effects still remain as major drawbacks. With the advancement of nanomedicine, new delivery strategies emerge at a regular pace, aiming to overcome these challenges. Stimulus-responsive drug delivery systems might considerably reduce systemic toxicity and side-effects by limiting drug release to the affected area. Herein, we report the development of paclitaxel-loaded lipid-coated manganese ferrite magnetic nanoparticles (PTX-LMNP) as magnetosomes synthetic analogs, envisaging the combined chemo-magnetic hyperthermia treatment of melanoma. PTX-LMNP physicochemical properties were verified, including their shape, size, crystallinity, FTIR spectrum, magnetization profile, and temperature profile under magnetic hyperthermia (MHT). Their diffusion in porcine ear skin (a model for human skin) was investigated after intradermal administration via fluorescence microscopy. Cumulative PTX release kinetics under different temperatures, either preceded or not by MHT, were assessed. Intrinsic cytotoxicity against B16F10 cells was determined via neutral red uptake assay after 48 h of incubation (long-term assay), as well as B16F10 cells viability after 1 h of incubation (short-term assay), followed by MHT. PTX-LMNP-mediated MHT triggers PTX release, allowing its thermal-modulated local delivery to diseased sites, within short timeframes. Moreover, half-maximal PTX inhibitory concentration (IC50) could be significantly reduced relatively to free PTX (142,500×) and Taxol® (340×). Therefore, the dual chemo-MHT therapy mediated by intratumorally injected PTX-LMNP stands out as a promising alternative to efficiently deliver PTX to melanoma cells, consequently reducing systemic side effects commonly associated with conventional chemotherapies. [ABSTRACT FROM AUTHOR]

Core–shell particles are micro- or nanoparticles with solid, liquid, or gas cores encapsulated by protective solid shells. The unique composition of core and shell materials imparts smart properties on the particles. Core–shell particles are gaining increasing attention as tuneable and versatile carriers for pharmaceutical and biomedical applications including targeted drug delivery, controlled drug release, and biosensing. This review provides an overview of fabrication methods for core–shell particles followed by a brief discussion of their application and a detailed analysis of their manipulation including assembly, sorting, and triggered release. We compile current methodologies employed for manipulation of core–shell particles and demonstrate how existing methods of assembly and sorting micro/nanospheres can be adopted or modified for core–shell particles. Various triggered release approaches for diagnostics and drug delivery are also discussed in detail. [ABSTRACT FROM AUTHOR]

Liver cancer, especially hepatocellular carcinoma, is an important cause of cancer-related death, and its incidence is increasing worldwide. Nano drug delivery systems have shown great promise in the treatment of cancers. In order to improve their therapeutic efficacy, it is very important to realize the high accumulation and effective release of drugs at the tumor site. In this manuscript, using doxorubicin (DOX) as a model drug, CD13-targeted mesoporous silica nanoparticles coated with NGR-peptide-modified pegylated carboxymethyl chitosan were constructed (DOX/MSN-CPN). DOX/MSN-CPN comprises a spherical shape with an obvious capping structure and a particle size of 125.01 ± 1.52 nm. With a decrease in pH, DOX/MSN-CPN showed responsive desorption from DOX/MSN-CPN and pH-responsive release of DOX was observed. Meanwhile, DOX/MSN-CPN could be efficiently absorbed through NGR-mediated internalization in vitro and could efficiently deliver DOX to tumor tissues with long accumulation times in vivo, suggesting good active targeting properties. Moreover, significant tumor inhibition has been observed in antitumor studies in vivo. This study provides a strategy of utilizing DOX/MSN-CPN as a nano-platform for drug delivery, which has superb therapeutic efficacy and safety for the treatment of hepatocellular carcinoma both in vivo and in vitro. [ABSTRACT FROM AUTHOR]

Chronic wound infections with antibiotic-resistant bacteria have become a significant problem for modern healthcare systems since they are often associated with high costs and require profound topical wound management. Successful wound healing is achieved by reducing the bacterial load of the wound and providing an environment that enhances cell growth. In this context, nanofibers show remarkable success because their structure offers a promising drug delivery platform that can mimic the native extracellular matrix and accelerate cell proliferation. In our study, single-needle electrospinning, a versatile and cost-efficient technique, was used to shape polymers into an applicable and homogeneous fleece capable of a photothermally triggered drug release. It was combined with antimicrobial photodynamic therapy, a promising procedure against resistant bacteria. Therefore, poly(d,l-lactide) nanofibers loaded with curcumin and indocyanine green (ICG) were produced for local antimicrobial treatment. The mesh had a homogeneous structure, and the nanofibers showed a smooth surface. Recordings with a thermal camera showed that near-infrared light irradiation of ICG increased the temperature (>44 °C) in the surrounding medium. Release studies confirmed more than 29% enhanced curcumin release triggered by elevated temperature. The antimicrobial activity was tested against the gram-positive strain Staphylococcus saprophyticus subsp. bovis and the gram-negative strain Escherichia coli DH5 alpha. The nanofibers loaded with both photosensitizers and irradiated with both wavelengths reduced the bacterial viability (~4.4 log10, 99.996%) significantly more than the nanofibers loaded with only one photosensitizer (<1.7 log10, 97.828%) or irradiated with only one wavelength (<2.0 log10, 98.952%). In addition, our formulation efficiently eradicated persistent adhered bacteria by >4.3 log10 (99.995%), which was also confirmed visually. Finally, the produced nanofibers showed good biocompatibility, proven by the cellular viability of mouse fibroblasts (L929). The data demonstrate that we have developed a new economic nanofiber formulation, which offers a triggered drug release, excellent antimicrobial properties, and good biocompatibility. [ABSTRACT FROM AUTHOR]

Nanocarriers (NCs) were designed from three polymer blends (B1, B2 and B3) and investigated as smart drug delivery systems (SDDS). The blends are composed of a "smart" copolymer, where methoxy poly(ethylene glycol) and poly(lactic acid) are connected via a redox-responsive disulfide bond (mPEG-SS-PLA), and of a "conventional" polymer, poly(lactic acid) (PLA). They differ by mPEG-SS-PLA/PLA ratio and PLA molecular weight. Nanoprecipitation was used to prepare NCs. Three concentrations were tested, and fluorescent dye Nile red (NR) was used as a model payload. The results show that the characteristics of the NCs, such as size and drug release kinetics, are influenced by the type of blend and the concentration used during the nanoprecipitation process. The more redox-responsive blend was B2 (ratio 1:3, PLA 5 kDa) at 16 mg/mL: the quantity of NR released was tripled upon 24 h of incubation in a reducing medium. This study reveals that the amount of disulfide bonds present in a NC is not the only parameter to be considered to design an SDDS. The stability of the SDDS in a presumably non-stimulating environment is also important to limit uncontrolled release during storage or in the body before the biological target is reached. [ABSTRACT FROM AUTHOR]

The development of new approaches for the treatment of the increasingly antibiotic-resistant pathogen Pseudomonas aeruginosa was targeted by enhancing the effect of local antimicrobial photodynamic therapy (aPDT) using poly(ethylene glycol)-block-poly(lactic acid) (PEG114-block-PLAx) nanocarriers that were loaded with a ruthenium-based photosensitizer (PS). The action of tris(1,10-phenanthroline) ruthenium (II) bis(hexafluorophosphate) (RuPhen3) encapsulated in PEG114-block-PLAx micelles and vesicles was shown to result in an appreciable aPDT inactivation efficiency against planktonic Pseudomonas aeruginosa. In particular, the encapsulation of the PS, its release, and the efficiency of singlet oxygen (1O2) generation upon irradiation with blue light were studied spectroscopically. The antimicrobial effect was analyzed with two strains of Pseudomonas aeruginosa. Compared with PS-loaded micelles, formulations of the PS-loaded vesicles showed 10 times enhanced activity with a strong photodynamic inactivation effect of at least a 4.7 log reduction against both a Pseudomonas aeruginosa lab strain and a clinical isolate collected from the lung of a cystic fibrosis (CF) patient. This work lays the foundation for the targeted eradication of Pseudomonas aeruginosa using aPDT in various medical application areas.

Abstract Chemotherapeutics that can trigger immunogenic cell death (ICD) and release tumor-specific antigens are effective on treating a variety of cancers. The codelivery of chemotherapeutics with adjuvants is a promising strategy to achieve synergistic therapeutic effect. However, low drug loading and complicated preparation of current delivery systems lead to carrier-associated toxicity and immunogenicity. Herein, we developed a facile approach to construct liposomal spherical nucleic acids (SNA) by the self-assembly of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE)-doxorubicin conjugate and DOPE-matrix metalloproteinases-9 (MMP-9) responsive peptide-CpG conjugate (DOPE-MMP-CpG). Liposomal SNAs efficiently co-delivered DOX and CpG into tumors and released the two drugs upon biological stimuli of MMP-9 enzyme in tumor microenvironment (TME) and high concentration of endogenous glutathione in tumor cells. We demonstrated that liposomal SNA enhanced activation of dendritic cells (DCs), promoted expansion of CD8+ and CD4+ T cells in both tumors and spleen, inhibited tumor growth, and extended animal survival. This work provided a simple strategy of delivering chemotherapeutics and adjuvants to tumors with synergistic therapeutic effect and reduced side effect. Graphical Abstract

Introduction: In targeted enzyme prodrug constructs, it is critical to control the bioactivity of the drug in its prodrug form. The preparation of such constructs often involves conjugation reactions directed to functional groups on amino acid side chains of the protein, which result in random conjugation and incomplete control of bioactivity of a prodrug, which may result in significant nontarget effect. Thus, more specific method of modification is desired. If the drug is a glycoprotein, enzymatic oxidation may offer an alternative approach for therapeutic glycoproteins. Methods: Tissue plasminogen activator (tPA), a model glycoprotein enzyme, was treated with galactose oxidase (GO) and horseradish peroxidase, followed by thiolation reaction and conjugation with low molecular weight heparin (LMWH). The LMWH-tPA conjugate was isolated by ion-exchange chromatography followed by centrifugal filtration. The conjugate was characterized for its fibrinolytic activity and for its plasminogen activation through an indirect amidolytic assay with a plasmin-specific substrate S-2251 when LMWH-tPA conjugate is complexed with protamine-albumin conjugate, followed by triggered activation in the presence of heparin. Results: LMWH-tPA conjugate prepared via enzymatic oxidation retained ~95% of its fibrinolytic activity with respect to native tPA. Upon complexation with protamine-albumin conjugate, the activity of LMWH-tPA was effectively inhibited (~90%) whereas the LMWH-tPA prepared by random thiolation exhibited ~55% inhibition. Addition of heparin fully generated the activities of both conjugates. Conclusion: The tPA was successfully modified via enzymatic oxidation by GO, resulting in enhanced control of its activity in the prodrug construct. This approach can be applied to other therapeutic glycoproteins. [ABSTRACT FROM AUTHOR]

This paper is to discuss the potential of using CuZn in an electrical biosensor drug carrier for drug delivery systems. CuZn is the main semiconductor ingredient that has great promise as an electrochemical detector to trigger releases of active pharmaceutical ingredients (API). This CuZn biosensor is produced with a green metal of frameworks, which is an anion node in conductive polymers linked by bioactive ligands using metal–polymerisation technology. The studies of Cu, Zn, and their oxides are highlighted by their electrochemical performance as electrical biosensors to electrically trigger API. The three main problems, which are glucose oxidisation, binding affinity, and toxicity, are highlighted, and their solutions are given. Moreover, their biocompatibilities, therapeutic efficacies, and drug delivery efficiencies are discussed with details given. Our three previous investigations of CuZn found results similar to those of other authors' in terms of multiphases, polymerisation, and structure. This affirms that our research is on the right track, especially that related to green synthesis using plant extract, CuZn as a nanochip electric biosensor, and bioactive ligands to bind API, which are limited to the innermost circle of the non-enzymatic glucose sensor category. [ABSTRACT FROM AUTHOR]

A novel approach to surface modification, which consists of the adsorption of microgel–enzyme complexes preformed in solution, is highlighted. Accordingly, the microgel–enzyme complexes were formed due to the electrostatic interaction of the oppositely charged interacting components, that is, a cationic poly(N-isopropylacrylamide)-based microgel and glucose oxidase taken as a model enzyme. The spontaneous adsorption of the prepared microgel–enzyme complexes, examined by means of quartz crystal microbalance with dissipation monitoring and atomic force microscopy, was observed, resulting in the formation of well-adhered microgel–enzyme coatings. Further, the preformed microgel–enzyme complexes were adsorbed onto the modified graphite-based screen-printed electrodes, and their enzymatic responses were determined by means of amperometry, demonstrating a remarkable analytical performance toward the quantification of β-D-glucose in terms of high sensitivity (0.0162 A × M−1 × cm−2), a low limit of detection (1 μM), and an expanded linear range (1–2000 μM). The fabricated microgel–enzyme biosensor constructs were found to be very stable against manifold-repeated measurements. Finally, the pH- or salt-induced release of glucose oxidase from the adsorbed preformed microgel–enzyme complexes was demonstrated. The findings obtained for the microgel–enzyme coatings prepared via adsorption of the preformed microgel–enzyme complexes were compared to those found for the microgel–enzyme coatings fabricated via a previously exploited two-stage sequential adsorption, which includes the adsorption of the microgel first, followed by the electrostatic binding of glucose oxidase by the adsorbed microgel.

Efficient conventional chemotherapy is limited by its nonspecific nature, which causes severe systemic toxicity that can lead to patient discomfort and low therapeutic efficacy. The emergence of smart drug delivery systems (SDDSs) utilizing nanoparticles as drug nanocarriers has shown great potential in enhancing the targetability of anticancer agents and limiting their side effects. Liposomes are among the most investigated nanoplatforms due to their promising capabilities of encapsulating hydrophilic, lipophilic, and amphiphilic drugs, biocompatibility, physicochemical and biophysical properties. Liposomal nanodrug systems have demonstrated the ability to alter drugs' biodistribution by sufficiently delivering the entrapped chemotherapeutics at the targeted diseased sites, sparing normal cells from undesired cytotoxic effects. Combining liposomal treatments with ultrasound, as an external drug release triggering modality, has been proven effective in spatially and temporally controlling and stimulating drug release. Therefore, this paper reviews recent literature pertaining to the therapeutic synergy of triggering nanodrugs from liposomes using ultrasound. It also highlights the effects of multiple physical and chemical factors on liposomes' sonosensetivity, several ultrasound-induced drug release mechanisms, and the efficacy of ultrasound-responsive liposomal systems in cancer therapy. Overall, liposomal nanodrug systems triggered by ultrasound are promising cancer therapy platforms that can potentially alleviate the detriments of conventional cancer treatments. [ABSTRACT FROM AUTHOR]

[Display omitted] According to the importance of time in treatment of thrombosis disorders, faster than current treatments are required. For the first time, this research discloses a novel strategy for rapid dissolution of blood clots by encapsulation of a fibrinolytic (Reteplase) into a Thrombin sensitive shell formed by polymerization of acrylamide monomers and bisacryloylated peptide as crosslinker. Degradability of the peptide units in exposure to Thrombin, creates the Thrombin-sensitive Reteplase nanocapsules (TSRNPs) as a triggered release system. Accelerated thrombolysis was achieved by combining three approaches including: deep penetration of TSRNPs into the blood clots, changing the clot dissolution mechanism by altering the distribution pattern of TSRNPs to 3D intra-clot distribution (based on the distributed intra-clot thrombolysis (DIT) model) instead of peripheral and unidirectional distribution of unencapsulated fibrinolytics and, enzyme-stimulated release of the fibrinolytic. Ex-vivo study was carried out by an occluded tube model that mimics in-vivo brain stroke as an emergency situation where faster treatment in short time is a golden key. In in vivo , efficacy of the developed formulation was confirmed by PET scan and laser Doppler flowmetry (LDF). As the most important achievements, 40.0 ± 0.7 (n = 3) % and 37.0 ± 0.4 (n = 3) % reduction in the thrombolysis time (faster reperfusion) were observed by ex-vivo and in-vivo experiments, respectively. Higher blood flow and larger digestion mass of clot at similar times in comparison to non-encapsulated Reteplase were observed that means more effective thrombolysis by the developed strategy. [ABSTRACT FROM AUTHOR]

[Display omitted] pH-responsive polymeric micelles have been extensively studied for nanomedicine and take advantage of pH differentials in tissues for the delivery of large doses of cytotoxic drugs at specific target sites. Despite significant advances in this area, there is a lack of versatile and adaptable strategies to render micelles pH-responsive that could be widely applied to different payloads and applications. To address this deficiency, we introduce the concept of oligoelectrolyte-mediated, pH-triggered release of hydrophobic drugs from non-responsive polymeric micelles as a highly effective approach with broad scope. Herein, we investigate the influence of the oligoelectrolyte, oligo(2-vinyl pyridine) (OVP), loading and polymer molecular weight on the pH-sensitivity, drug loading/release and cytotoxicity of poly(ethylene glycol- b -ε-caprolactone) (PEG- b -PCL) micelles using copolymers with either short or long hydrophobic blocks (PEG 4 PCL 4 and PEG 10 PCL 10 , respectively). The micelles were characterized as a function of pH (7.4 to 3.5). Dynamic light scattering (DLS) revealed narrow particle size distributions (PSDs) for both the blank and OVP-loaded micelles at pH 7.4. While OVP encapsulation resulted in an increase in the hydrodynamic diameter (D h) (cf. blank micelles), a decrease in the pH below 6.5 led to a decrease in the D h consistent with the ionization and release of OVP and core collapse, which were further supported by proton nuclear magnetic resonance (1H NMR) spectroscopy and UV–visible (UV–vis) spectrophotometry. The change in zeta potential (ζ) with pH for the OVP-loaded PEG 4 PCL 4 and PEG 10 PCL 10 micelles was different, suggesting that the location/distribution of OVP in the micelles is influenced by the polymer molecular weight. In general, co-encapsulation of drugs (doxorubicin (DOX), gossypol (GP), paclitaxel (PX) or 7-ethyl-10-hydroxycamptothecin (SN38)) and OVP in the micelles proceeded efficiently with high encapsulation efficiency percentages (EE%). In vitro release studies revealed the rapid, pH-triggered release of drugs from OVP-loaded PEG 10 PCL 10 micelles within hours, with higher OVP loadings providing faster and more complete release. In comparison, no triggered release was observed for the OVP-loaded PEG 4 PCL 4 micelles, implying a strong molecular weight dependency. In metabolic assays the drug- and OVP-loaded PEG 10 PCL 10 micelles were found to result in significant enhancement of the cytotoxicity compared to drug-loaded micelles (no OVP) or other controls. Importantly, micelles with low OVP loadings were found to be nearly as effective as those with high OVP loadings. These results provide key insights into the tunability of the oligoelectrolyte-mediated approach for the effective formulation of pH-responsive micelles and pH-triggered drug release. [ABSTRACT FROM AUTHOR]

Multidrug‐resistant bacteria have become a global health problem for which new prophylactic strategies are now needed, including surface‐coatings for hospital spaces and medical equipment. This work reports the preparation and functional validation of a metal‐organic framework (MOF) based composite for the triggered controlled release of iodine, an antimicrobial element that does not generate resistance. It comprises beads of the iodophilic MOF UiO‐66 containing encapsulated gold nanorods (AuNRs) coated with a silica shell. Irradiation of the AuNRs with near‐infrared light (NIR) provokes a photothermal effect and the resultant heat actively liberates the iodine. After validating the performance of this composite, it is integrated into a polymer for the development of antibacterial films. This work assesses the adsorption of iodine into these composite films, as well as its passive long‐term release and active light‐triggered. Finally, this work validates the antibacterial activity of the composite films in vitro against gram‐positive and gram‐negative bacteria. The findings will surely inform the development of new prophylactic treatments. [ABSTRACT FROM AUTHOR]

Bioactive compounds (e.g., nutraceuticals, micronutrients, antimicrobial, antioxidant) are added to food products and formulations to enhance sensorial/nutritional attributes and/or shelf-life. Many of these bioactives are susceptible to degradation when exposed to environmental and processing factors. Others involve in undesirable interactions with food constituents. Encapsulation is a useful tool for addressing these issues through various stabilization mechanisms. Besides protection, another important requirement of encapsulation is to design a carrier that predictably releases the encapsulated bioactive at the target site to elicit its intended functionality. To this end, controlled release carrier systems derived from interactive materials have been developed and commercially exploited to meet the requirements of various applications. This chapter provides an overview on basic controlled and triggered release concepts relevant to food and active packaging applications. Different approaches to encapsulate bioactive compounds and their mode of release are presented, from simple blending with a compatible matrix to complex multiphase carrier systems. To further elucidate the mass transport processes, selected diffusion and empirical release kinetic models are presented, along with their brief historical significance. Finally, interactive carriers that are responsive to moisture, pH, thermal and chemical stimuli are presented to illustrate how these triggered release mechanisms can be useful for food applications. [ABSTRACT FROM AUTHOR]

The design of biocompatible multiple emulsions is an important challenge in the field of controlled delivery systems for protecting and delivering compounds encapsulated and protected in the innermost phase. In this paper, we use biocompatible water – Miglyol®812 water-in-oil-in-water (W/O/W) emulsions stabilized by a stimuli-responsive diblock copolymer consisting of poly(dimethylsiloxane) (PDMS) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) to design an easy-to-process new delivery W/O/W system. Such emulsions are formed in a single emulsification step. They present a high encapsulation yield and are shown to be stable over months. As such, the encapsulation of a hydrophilic dye (Alexa fluor) in the innermost water phase is successfully demonstrated over months. These emulsions are stimulable either by a shift in pH level or in ionic strength. The former destabilizes the multiple emulsion and leads to a simple one while the latter partly maintains the multiple character. Eventually both stimulations are effective in the dye release and molecular mechanisms are proposed for explaining the observed two-stage kinetics of release.

The potential of semiochemicals for the targeted behavior manipulation of insects has been known for a long time. Their low impact on non-target organisms makes them interesting candidates for use in insect control for various applications such as agricultural and forestry pest control, stored-product protection and protection against hematophagous insects. Due to their high volatility and chemical instability against UV light and oxidation, their use often remains limited. Tailor-made formulations can protect semiochemicals from environmental factors and can improve release performance and duration triggering a desired reaction in the target insect at the place of application. This review provides an overview of recent formulation types developed for insect behavior manipulation by semiochemicals, with emphasis on formulation aspects and formulation potential for slow and controlled release. The focus was set on inventions and studies aiming to elucidate material and formulation properties that affect the semiochemical release and, with specific attention, enable targeted release manipulation. [ABSTRACT FROM AUTHOR]

The folate receptor alpha (FR), which is overexpressed in solid tumors including NSCLC, can be utilized for active tumor targeting to afford more effective cancer therapies. In this context, cytochrome c (Cyt c) has drawn attention to cancer research because it is non-toxic, yet, when delivered to the cytoplasm of cancer cells, can kill them by inducing apoptosis. Cyt c nanoparticles (NPs, 169 ± 9 nm) were obtained by solvent precipitation with acetonitrile, and stabilized by reversible homo-bifunctional crosslinking to accomplish a Cyt-c-based drug delivery system that combines stimulus-responsive release and active targeting. Cyt c was released under intracellular redox conditions, due to an S–S bond in the NPs linker, while NPs remained intact without any release under extracellular conditions. The NP surface was decorated with a hydrophilic folic acid–polyethylene glycol (FA–PEG) polymer for active targeting. The FA-decorated NPs specifically recognized and killed cancer cells (IC50 = 47.46 µg/mL) that overexpressed FR, but showed no toxicity against FR-negative cells. Confocal microscopy confirmed the preferential uptake and apoptosis induction of our NPs by FR-positive cancer cells. In vivo experiments using a Lewis lung carcinoma (LLC) mouse model showed visible NP accumulation within the tumor and inhibited the growth of LLC tumors. [ABSTRACT FROM AUTHOR]

Melanoma is the most aggressive and metastasis-prone form of skin cancer. Conventional therapies include chemotherapeutic agents, either as small molecules or carried by FDA-approved nanostructures. However, systemic toxicity and side effects still remain as major drawbacks. With the advancement of nanomedicine, new delivery strategies emerge at a regular pace, aiming to overcome these challenges. Stimulus-responsive drug delivery systems might considerably reduce systemic toxicity and side-effects by limiting drug release to the affected area. Herein, we report the development of paclitaxel-loaded lipid-coated manganese ferrite magnetic nanoparticles (PTX-LMNP) as magnetosomes synthetic analogs, envisaging the combined chemo-magnetic hyperthermia treatment of melanoma. PTX-LMNP physicochemical properties were verified, including their shape, size, crystallinity, FTIR spectrum, magnetization profile, and temperature profile under magnetic hyperthermia (MHT). Their diffusion in porcine ear skin (a model for human skin) was investigated after intradermal administration via fluorescence microscopy. Cumulative PTX release kinetics under different temperatures, either preceded or not by MHT, were assessed. Intrinsic cytotoxicity against B16F10 cells was determined via neutral red uptake assay after 48 h of incubation (long-term assay), as well as B16F10 cells viability after 1 h of incubation (short-term assay), followed by MHT. PTX-LMNP-mediated MHT triggers PTX release, allowing its thermal-modulated local delivery to diseased sites, within short timeframes. Moreover, half-maximal PTX inhibitory concentration (IC50) could be significantly reduced relatively to free PTX (142,500×) and Taxol® (340×). Therefore, the dual chemo-MHT therapy mediated by intratumorally injected PTX-LMNP stands out as a promising alternative to efficiently deliver PTX to melanoma cells, consequently reducing systemic side effects commonly associated with conventional chemotherapies.

Core–shell particles are micro- or nanoparticles with solid, liquid, or gas cores encapsulated by protective solid shells. The unique composition of core and shell materials imparts smart properties on the particles. Core–shell particles are gaining increasing attention as tuneable and versatile carriers for pharmaceutical and biomedical applications including targeted drug delivery, controlled drug release, and biosensing. This review provides an overview of fabrication methods for core–shell particles followed by a brief discussion of their application and a detailed analysis of their manipulation including assembly, sorting, and triggered release. We compile current methodologies employed for manipulation of core–shell particles and demonstrate how existing methods of assembly and sorting micro/nanospheres can be adopted or modified for core–shell particles. Various triggered release approaches for diagnostics and drug delivery are also discussed in detail.

Chronic wound infections with antibiotic-resistant bacteria have become a significant problem for modern healthcare systems since they are often associated with high costs and require profound topical wound management. Successful wound healing is achieved by reducing the bacterial load of the wound and providing an environment that enhances cell growth. In this context, nanofibers show remarkable success because their structure offers a promising drug delivery platform that can mimic the native extracellular matrix and accelerate cell proliferation. In our study, single-needle electrospinning, a versatile and cost-efficient technique, was used to shape polymers into an applicable and homogeneous fleece capable of a photothermally triggered drug release. It was combined with antimicrobial photodynamic therapy, a promising procedure against resistant bacteria. Therefore, poly(d,l-lactide) nanofibers loaded with curcumin and indocyanine green (ICG) were produced for local antimicrobial treatment. The mesh had a homogeneous structure, and the nanofibers showed a smooth surface. Recordings with a thermal camera showed that near-infrared light irradiation of ICG increased the temperature (>44 °C) in the surrounding medium. Release studies confirmed more than 29% enhanced curcumin release triggered by elevated temperature. The antimicrobial activity was tested against the gram-positive strain Staphylococcus saprophyticus subsp. bovis and the gram-negative strain Escherichia coli DH5 alpha. The nanofibers loaded with both photosensitizers and irradiated with both wavelengths reduced the bacterial viability (~4.4 log10, 99.996%) significantly more than the nanofibers loaded with only one photosensitizer (10, 97.828%) or irradiated with only one wavelength (10, 98.952%). In addition, our formulation efficiently eradicated persistent adhered bacteria by >4.3 log10 (99.995%), which was also confirmed visually. Finally, the produced nanofibers showed good biocompatibility, proven by the cellular viability of mouse fibroblasts (L929). The data demonstrate that we have developed a new economic nanofiber formulation, which offers a triggered drug release, excellent antimicrobial properties, and good biocompatibility.

Liver cancer, especially hepatocellular carcinoma, is an important cause of cancer-related death, and its incidence is increasing worldwide. Nano drug delivery systems have shown great promise in the treatment of cancers. In order to improve their therapeutic efficacy, it is very important to realize the high accumulation and effective release of drugs at the tumor site. In this manuscript, using doxorubicin (DOX) as a model drug, CD13-targeted mesoporous silica nanoparticles coated with NGR-peptide-modified pegylated carboxymethyl chitosan were constructed (DOX/MSN-CPN). DOX/MSN-CPN comprises a spherical shape with an obvious capping structure and a particle size of 125.01 ± 1.52 nm. With a decrease in pH, DOX/MSN-CPN showed responsive desorption from DOX/MSN-CPN and pH-responsive release of DOX was observed. Meanwhile, DOX/MSN-CPN could be efficiently absorbed through NGR-mediated internalization in vitro and could efficiently deliver DOX to tumor tissues with long accumulation times in vivo, suggesting good active targeting properties. Moreover, significant tumor inhibition has been observed in antitumor studies in vivo. This study provides a strategy of utilizing DOX/MSN-CPN as a nano-platform for drug delivery, which has superb therapeutic efficacy and safety for the treatment of hepatocellular carcinoma both in vivo and in vitro.

Many important food bioactive compounds are plant secondary metabolites that have traditional applications for health promotion and disease prevention. However, the chemical instability and poor bioavailability of these compounds represent major challenges to researchers. In the last decade, therefore, major impetus has been given for the research and development of advanced carrier systems for the delivery of natural bioactive molecules. Among them, stimuli‐responsive carriers hold great promise for simultaneously improving stability, bioavailability, and more importantly delivery and on‐demand release of intact bioactive phytochemicals to target sites in response to certain stimuli or combination of them (e.g., pH, temperature, oxidant, enzyme, and irradiation) that would eventually enhance therapeutic outcomes and reduce side effects. Hybrid formulations (e.g., inorganic–organic complexes) and multi‐stimuli‐responsive formulations have demonstrated great potential for future studies. Therefore, this review systematically compiles and assesses the recent advances on the smart delivery of food bioactive compounds, particularly quercetin, curcumin, and resveratrol through stimuli‐responsive carriers, and critically reviews their functionality, underlying triggered‐release mechanism, and therapeutic potential. Finally, major limitations, contemporary challenges, and possible solutions/future research directions are highlighted. Much more research is needed to optimize the processing parameters of existing formulations and to develop novel ones for lead food bioactive compounds to facilitate their food and nutraceutical applications. [ABSTRACT FROM AUTHOR]

Core-shell nanoparticles comprised of Fe3O4 cores and a mesoporous silica shell with an average expanded pore size of 6.07 nm and coated with a poly(N-isopropylacrylamide) (PNIPAM) layer (CS-MSNs-EP-PNIPAM) were prepared and characterized. The nanoparticles was loaded with (Ru(bipy)3(2+)) dye or an antibacterial enzyme, lysozyme, to obtain CS-MSNs-EP-PNIPAM-Ru(bipy)3(2+) and CS-MSNs-EP-PNIPAM-Lys, respectively. The lysozyme loading was determined to be 160 mg/g of nanoparticle. It was seen that Ru(bipy)3(2+) and lysozyme release was minimal at a room temperature of 25 °C while at physiological temperature (37 °C), abrupt release was observed. The applicability of the CS-MSNs-EP-PNIPAM-Lys was further tested with two Gram-positive bacteria samples, Bacillus cereus and Micrococcus luteus. At physiological temperature, the nanoparticles were shown to reduce bacterial growth, indicating a successful release of lysozyme from the nanoparticles. This nanoparticle system shows potential as a nanocarrier for the loading of similarly sized proteins or other species as a drug delivery platform.

Subarachnoid hemorrhage (SAH) is a fatal disease. Within 72 h of SAH, the intracranial blood-brain barrier (BBB) is destroyed, and the nerve cells have responses such as autophagy, apoptosis, and oxidative stress. Antioxidation is an essential treatment of SAH. Astaxanthin (ATX) induces cells’ antioxidant behaviors by regulating related signal pathways to reduce the damage of brain oxidative stress, inflammation, and apoptosis. Because of its easy degradability and low bioavailability, ATX is mainly encapsulated with stimulus-responsive nanocarriers to improve its stability, making it rapidly release in the brain and efficiently enter the lesion tissue. In this study, the ultrasonic cavitation agent perfluorocarbon (PFH), ATX, and fluorescent dye IR780 were loaded with polydopamine (PDA) to prepare a US triggered release nanoparticles (AUT NPs). The core-shell structure of AUT NPs formed a physical barrier to improve the bioavailability of ATX. AUT NPs have high ATX loading capacity and US responsiveness. The experimental results show that the AUT NPs have high stability in the physiological environment. Both US and pH stimuli can trigger the release. Under US, PFH breaks through the rigid shell. The structure of AUT NPs is destroyed in situ, releasing the loaded drugs into neuronal cells to realize the antioxidant and antiapoptotic effects. The in vivo experiment results show that the AUT NPs have good biosafety. They release the drugs in the brain under stimuli. The in vivo treatment results also show that AUT NPs have an excellent therapeutic effect. This approach presents an experimental basis for the establishment of Innovative SAH treatments.

Triple-negative breast cancer (TNBC) has inadequate treatment approaches and a poor prognosis. It is urgent to develop new treatment approaches for TNBC. The combination of photothermal therapy (PTT) and chemotherapy is a very effective potential therapy for TNBC. However, asynchronous accumulation, unclear efficacy, and toxic side effects hinder the further promotion of this method. Therefore, we designed and constructed a new type of nanocarriers, the cascade release near-infrared imaging (NIFI) & thermal-chemo combination nanoparticles (CNC NPs), that can release drugs through the cascade of ultrasound triggering and pH responding to achieve the synchronous tumor accumulation, monitoring and synergistic treatment of two functional molecules. The key material of CNC NPs is the polydopamine (PDA), which, through self-assembling, forms a rigid shell that contains doxorubicin (DOX) and NIF fluorescent dye IR780 on the surface of the perfluorohexane (PFH) microbubbles. The results show that CNC NPs have a hollow core-shell structure with an average particle size of 97.3 ± 27.2 nm and have exceptional colloidal stability and photothermal conversion efficiency. The NPs can effectively perform cascade drug release through ultrasound triggering and pH responding. CNC NPs have good in vivo biological safety and excellent fluorescence imaging, drug delivery, and therapeutic abilities in the TNBC models. These results provide an experimental basis for the development of new clinical treatment methods for TNBC.

Triple-negative breast cancer (TNBC) has inadequate treatment approaches and a poor prognosis. It is urgent to develop new treatment approaches for TNBC. The combination of photothermal therapy (PTT) and chemotherapy is a very effective potential therapy for TNBC. However, asynchronous accumulation, unclear efficacy, and toxic side effects hinder the further promotion of this method. Therefore, we designed and constructed a new type of nanocarriers, the cascade release near-infrared imaging (NIFI) & thermal-chemo combination nanoparticles (CNC NPs), that can release drugs through the cascade of ultrasound triggering and pH responding to achieve the synchronous tumor accumulation, monitoring and synergistic treatment of two functional molecules. The key material of CNC NPs is the polydopamine (PDA), which, through self-assembling, forms a rigid shell that contains doxorubicin (DOX) and NIF fluorescent dye IR780 on the surface of the perfluorohexane (PFH) microbubbles. The results show that CNC NPs have a hollow core-shell structure with an average particle size of 97.3 ± 27.2 nm and have exceptional colloidal stability and photothermal conversion efficiency. The NPs can effectively perform cascade drug release through ultrasound triggering and pH responding. CNC NPs have good in vivo biological safety and excellent fluorescence imaging, drug delivery, and therapeutic abilities in the TNBC models. These results provide an experimental basis for the development of new clinical treatment methods for TNBC. [ABSTRACT FROM AUTHOR]

Hybrid lipopolymer vesicles are membrane vesicles that can be self-assembled on both the micro- and nanoscale. On the nanoscale, they are potential novel smart materials for drug delivery systems that could combine the relative strengths of liposome and polymersome drug delivery systems without their respective weaknesses. However, little is known about their properties and how they could be tailored. Currently, most methods of investigation are limited to the microscale. Here we provide a brief review on hybrid vesicle systems with a specific focus on recent developments demonstrating that nanoscale hybrid vesicles have different properties from their macroscale counterparts. [ABSTRACT FROM AUTHOR]

The low oral bioavailability of some bioactive ingredients is a challenge in the supplement and functional food areas. Consequently, there is a need for innovative carrier technologies that can increase the solubility, stability, release, and absorption of these ingredients within the human gastrointestinal tract. Furthermore, some bioactive ingredients may exert their synergistic activities when delivered together. The objective of this study was to design natural carriers that could simultaneously deliver both hydrophobic and hydrophilic bioactive ingredients, thereby increasing their ability to exert synergistic effects. Initially, model hydrophobic (lycopene) and hydrophilic (riboflavin) ingredients were encapsulated in the oil and internal water phases of water-in-oleic acid-in-water (W/O/W) emulsions, respectively. These emulsions were then dispersed into two kinds of alginate-based matrices, which may be suitable for different applications: calcium alginate gels (solid) or EDTA-calcium alginate sols (fluid). Oleic acid was used as an oil phase in the W/O/W emulsions to provide temperature-triggered release, whereas alginate-based matrices were used to provide pH-triggered release. The carriers were stable in a simulated gastric juice but released the bioactive ingredients in a simulated small intestinal juice. The calcium alginate matrix increased the light stability of the bioactive ingredients. Encapsulation improved the bioaccessibility of the co-delivered bioactive ingredients. This study provides new strategies that can be used for designing pH- and temperature-sensitive carrier for intestinal targeted delivery of hydrophobic and hydrophilic food bioactive ingredients. [Display omitted] • Natural pH and temperature-sensitive hydrogel-emulsion carriers were established. • These carriers can be used to co-deliver hydrophobic carotenoids and hydrophilic riboflavin. • The gel-sol state transition of the carriers can be controlled by calcium ions. • Carriers with gel state gave better photostability and bioaccessibility of the carotenoid. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling remote and spatiotemporal control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or coencapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution.

Abstract Pesticides and fertilizers are widely used to enhance agriculture yields, although the fraction of the pesticides applied in the field that reaches the targets is less than 0.1%. Such indiscriminate use of chemical pesticides is disadvantageous due to the cost implications and increasing human health and environmental concerns. In recent years, the utilization of nanotechnology to create novel formulations has shown great potential for diminishing the indiscriminate use of pesticides and providing environmentally safer alternatives. Smart nano-based pesticides are designed to efficiently delivery sufficient amounts of active ingredients in response to biotic and/or abiotic stressors that act as triggers, employing targeted and controlled release mechanisms. This review discusses the current status of stimuli-responsive release systems with potential to be used in agriculture, highlighting the challenges and drawbacks that need to be overcome in order to accelerate the global commercialization of smart nanopesticides.

Efficient conventional chemotherapy is limited by its nonspecific nature, which causes severe systemic toxicity that can lead to patient discomfort and low therapeutic efficacy. The emergence of smart drug delivery systems (SDDSs) utilizing nanoparticles as drug nanocarriers has shown great potential in enhancing the targetability of anticancer agents and limiting their side effects. Liposomes are among the most investigated nanoplatforms due to their promising capabilities of encapsulating hydrophilic, lipophilic, and amphiphilic drugs, biocompatibility, physicochemical and biophysical properties. Liposomal nanodrug systems have demonstrated the ability to alter drugs’ biodistribution by sufficiently delivering the entrapped chemotherapeutics at the targeted diseased sites, sparing normal cells from undesired cytotoxic effects. Combining liposomal treatments with ultrasound, as an external drug release triggering modality, has been proven effective in spatially and temporally controlling and stimulating drug release. Therefore, this paper reviews recent literature pertaining to the therapeutic synergy of triggering nanodrugs from liposomes using ultrasound. It also highlights the effects of multiple physical and chemical factors on liposomes’ sonosensetivity, several ultrasound-induced drug release mechanisms, and the efficacy of ultrasound-responsive liposomal systems in cancer therapy. Overall, liposomal nanodrug systems triggered by ultrasound are promising cancer therapy platforms that can potentially alleviate the detriments of conventional cancer treatments.

A hydrogel microcapsule with an intermediate thin oil layer is presented to achieve smart release of a broad range of cargoes triggered via diverse stimuli. A microfluidic technique is used to produce triple emulsion droplets with a thin oil layer that separates the innermost aqueous phase from the hydrogel prepolymer phase, which transforms into a hydrogel shell via photo-polymerization. The intermediate oil layer within the hydrogel microcapsule acts as an effective diffusion barrier, allowing encapsulation of various small cargoes within a porous hydrogel shell until a stimulus is applied to destabilize the oil layer. It is demonstrated that diverse stimuli including chemical dissolution, mechanical stress, and osmotic pressure can be utilized to release the encapsulated cargo on-demand. In addition, osmotic pressure and the hydrogel shell thickness can be independently tuned to control the onset time of release as well as the release behavior of multi-cargo encapsulated hydrogel microcapsule. The release can be either simultaneous or selective. [ABSTRACT FROM AUTHOR]

Since more than 40 years liposomes have being extensively studied for their potential as carriers of anticancer drugs. The basic principle behind their use for cancer treatment consists on the idea that they can take advantage of the leaky vasculature and poor lymphatic drainage present at the tumor tissue, passively accumulating in this region. Aiming to further improve their efficacy, different strategies have been employed such as PEGlation, which enables longer circulation times, or the attachment of ligands to liposomal surface for active targeting of cancer cells. A great challenge for drug delivery to cancer treatment now, is the possibility to trigger release from nanosystems at the tumor site, providing efficacious levels of drug in the tumor. Different strategies have been proposed to exploit the outer and inner tumor environment for triggering drug release from liposomes and are the focus of this review.

Since more than 40 years liposomes have being extensively studied for their potential as carriers of anticancer drugs. The basic principle behind their use for cancer treatment consists on the idea that they can take advantage of the leaky vasculature and poor lymphatic drainage present at the tumor tissue, passively accumulating in this region. Aiming to further improve their efficacy, different strategies have been employed such as PEGlation, which enables longer circulation times, or the attachment of ligands to liposomal surface for active targeting of cancer cells. A great challenge for drug delivery to cancer treatment now, is the possibility to trigger release from nanosystems at the tumor site, providing efficacious levels of drug in the tumor. Different strategies have been proposed to exploit the outer and inner tumor environment for triggering drug release from liposomes and are the focus of this review. [ABSTRACT FROM AUTHOR]

License to fuse! A phosphorylated fusion peptide can mediate membrane fusion when the phosphates (green triangles, see scheme) are removed by phosphatases (blue spheres), delivering the contents of the liposome into the cytosol. This phosphatase-triggered approach may be useful to create target-specific lipid nanocarriers.

Triggered release from responsive drug reservoirs activated by remote stimuli is desired in a range of fields. Critical bottlenecks are cost-efficient formulation avenues applicable for industrial scale-up, viable triggers and immediate release rather than continuous release upon activation. UV-sensitive microcapsules based on self-immolating polymers in combination with thin shells and morphological weak spots should allow for immediate triggered release. Polyphthalaldehyde-based microcapsules were prepared using several variations of the internal phase separation route. In addition, a fluorescence microscopy method was developed to study both the microcapsule morphology and the triggered release in-situ. The microcapsule formation was driven by the surface activity of the stabilizer, effectively lowering the high polymer-water interfacial tension, which is in sharp contrast to conventional encapsulation systems. Contrary to previous findings, a core–shell morphology was obtained via slow emulsion-to-suspension transformation. Rapid transformation captured intermediate inverted core–shell structures. The capsules were highly sensitive to both acid- and UV-mediated triggers, leading to an unzipping and rupturing of the shell that released the core content. Poly(methacrylic acid)-stabilized microcapsules displayed immediate UV-triggered release provided by their stimuli-sensitive blueberry morphology. Both capsules in aqueous and dry environment started to lose their core content after less than one minute of UV light exposure. [ABSTRACT FROM AUTHOR]

Smart drugs, such as antibody‐drug conjugates, for targeted therapy rely on the ability to deliver a warhead to the desired location and to achieve activation at the same site. Thus, designing a smart drug often requires proper linker chemistry for tethering the warhead with a vehicle in such a way that either allows the active drug to retain its potency while being tethered or ensures release and thus activation at the desired location. Recent years have seen much progress in the design of new linker activation strategies. Herein, we review the recent development of chemical strategies used to link the warhead with a delivery vehicle for preferential cleavage at the desired sites. [ABSTRACT FROM AUTHOR]