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Epitope-based vaccine is a promising personalized cancer immunotherapy; however, a simple and effective approach for its bulk manufacturing is challenging. Current vaccination strategies complicate the process by introducing unnecessary components such as additional delivery carriers, and assembly units. Herein, a type of toll-like receptor 7/8 agonist-epitope conjugate (termed as TLR7/8a-epitope) has been developed as a self-assembled and carrier-free nano vaccine platform, which effectively introduces the antigen and adjuvant with maximum precision, resulting in significantly enhanced dendritic cells (DCs) activation through the MyD88-dependent TLR signaling pathway. TLR7/8a-epitope nanovaccine can prolong the local retention and increase drainage efficiency into the lymph node, eliciting a significantly higher level of CD8 T-cell immunity than those of conventional vaccine formulations. The immunization with TLR7/8a-epitope nanovaccine in mice can not only resist the invasion of B16 cancer cells, but also produce significant therapeutic effects against established B16 melanoma tumors. Therefore, the TLR7/8a-epitope nanovaccine, developed by the direct chemical conjugation of antigen peptide with immunoadjuvant, has great advantages of clear and leanest compositions, controllable and definite preparation process, and remarkable therapeutic effects, representing a new appraoch for personalized cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Herein, a kind of toll-like receptor 7/8 agonist-epitope conjugate was developed and spontaneously self-assemble into nanostructure in aqueous solution without the use of any additional constituents, which can be termed as unique carrier-free nanovaccine platform, providing effectually the leanest vaccine components with maximally and precisely loading of antigen and adjuvant. Significantly, the nanovaccine augmented the immunogenicity of antigenic peptide by increasing DCs activation through MyD88-mediated TLR signaling pathways and promoting T-cell priming. Moreover, nanovaccines could prolong the local retention and further increase the efficiency of drainage into dLNs, which was contributing to efficient initiation of epitope-specific memory and effector T-cell immune responses, leading to effective prophylactic and therapeutic antitumor effects.

IL-2/IL-12-loaded SiO2–MAL was conjugated on the surface of DCs. DCs and T cells formed a positive feedback loop, providing long-term anti-tumor protection.

A microscale vaccine containing SiO2 nanoparticles loaded in CaCO3 microparticles was constructed using the co-precipitation method. The antigen ovalbumin (OVA) was covalently conjugated with SiO2 nanoparticles, and these nanoparticles and CpG were co-encapsulated into CaCO3 microparticles, generating a vaccine with a size of approximately 5.2 μm. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), elemental mapping, and Fourier transform infrared (FTIR) analyses confirmed the successful preparation of the microscale vaccine; the vaccine had good storage stability without sustained antigen release, and negligible cytotoxicity to dendritic cells (DCs) and macrophages. Compared to SiO2 nanoparticles, the microscale vaccine can significantly improve antigen/adjuvant uptake. DCs internalized the entire microscale vaccine into lysosomes via macropinocytosis, and an increase in antigen endo/lysosomal escape was observed by confocal laser scanning microscopy (CLSM). Specifically, DCs pulsed with the vaccine were fully mature, expressing high levels of costimulatory molecules (CD40, CD80, and CD86), MHC II, and MHC I and secreting high levels of proinflammatory cytokines (IL-12, TNF-α, IL-1β, and IL-6). In addition, the vaccine had good in vivo biocompatibility, could protect the antigen from rapid degradation, and increased the retention time in lymph nodes. SiO2 nanoparticles-in-CaCO3 microparticles were an excellent carrier for antigen and adjuvant delivery. Hopefully, this study can provide some information on the design of microscale carriers for vaccine delivery systems.

Pancreatic islet surface engineering has been proposed as an "easy-to-adopt" approach to enhance post-transplantation islet engraftment for treatment against diabetes. Inulin is an FDA-approved dietary prebiotic with reported anti-diabetic, anti-inflammatory, anti-hypoxic and pro-angiogenic properties. We therefore assessed whether inulin would be a viable option for islet surface engineering. Inulin was oxidized to generate inulin-CHO, which would bind to the cell membrane

Peptide vaccine targeting tumor-specific antigens is a promising cancer treatment regimen. However, peptide vaccines are commonly low-immunogenic, leading to suboptimal antitumor T-cell responses. Current peptide vaccination approaches are challenged by the variability of peptide physicochemical characters and vaccine formulations, flexibility, and the broad feasibility. Here, the supramolecular co-assembly of antigen epitope-conjugated peptides (ECPs) targeting CD8 or CD4 T-cell receptors was used to engineer a nanofibrious hydrogel vaccine platform. This approach provided precise and tunable loading of peptide antigens in nanofibers, which notably increased the antigen uptake, cross-presentation, and activation of dendritic cells (DCs). Immunization in mice indicated that the co-assembled peptide hydrogel did not induce local inflammation responses and elicited significantly promoted T-cell immunity by activating the MyD88-dependent NF-κB signaling pathway in DCs. Vaccination of mice using co-assembled peptide vaccine stimulated both enhanced CD8 and CD4 T cells against EG.7-OVA tumors without additional immunoadjuvants or delivery systems, and resulted in a more remarkable cancer immunotherapy efficacy, compared with free peptide vaccine or aluminum-adjuvanted peptide formulation. Altogether, peptide co-assembly demonstrated by three independent pairs of ECPs is a facile, customizable, and chemically defined approach for co-delivering peptide antigens in self-adjuvanting hydrogel vaccines that could induce stronger anticancer T-cell responses., Graphical abstract Image 1, Highlights • Supramolecular co-assembly is a facile approach for manufacturing peptide vaccine. • Peptide vaccine activates DCs through the MyD88-dependent NF-κB signaling pathway. • Vaccination of co-assembled peptide hydrogel augments antitumor T-cell responses. • Co-assembled peptide vaccine shows therapeutic cancer immunotherapy efficacy.

The imaging of hydrogel scaffolds by

Here, we reported a cancer nanovaccine based on SiO2 nanoflowers with a special radial pore structure, which greatly enhanced cross-presentation and induced the production of cytotoxic T lymphocyte cells secreting granzymes B and interferon-γ. The antigen ovalbumin was covalently conjugated onto the as-synthesized hierarchical SiO2 nanoflowers, and the adjuvant cytosine-phosphate-guanine was electrostatically adsorbed into their radial pore by simple mixing before use. The nanovaccine exhibited excellent storage stability without antigen release after 27 days of incubation, negligible cytotoxicity to dendritic cells, and a high antigen loading capacity of 430 ± 66 mg·g−1 support. Besides, the nanovaccine could be internalized by dendritic cells via multiple pathways. And the enhancement of antigen/adjuvant uptake and lysosome escape of antigen were observed. Noteworthy, in vitro culture of bone marrow-derived dendritic cells in the presence of nanovaccine proved the activation of dendritic cells and antigen cross-presentation as well as secretion of proinflammatory cytokines. Besides, in vivo study verified the targeting of nanovaccine to draining lymph nodes, the complete suppression of tumor in six out of ten mice, and the triggering of notable tumor growth delay. Overall, the present results indicated that the nanovaccine can be served as a potential therapeutic vaccine to treat cancer.

The treatment of difficult-to-heal wounds remains a substantial clinical challenge due to deteriorative tissue microenvironment including the loss of extracellular matrix (ECM), excessive inflammation, impaired angiogenesis, and bacterial infection. Inspired by the chemical components, fibrous structure, and biological function of natural ECM, antibacterial and tissue environment-responsive glycopeptide hybrid hydrogel was developed for chronic wound healing. The hydrogel can facilitate the cell proliferation and macrophage polarization to M2 phenotype, and show potent antibacterial efficacy against both Gram-negative and Gram-positive bacteria. Significantly, the glycopeptide hydrogel accelerated the reconstruction of methicillin-resistant

Antibacterial hydrogels are attracting extensive attention in soft tissue repair and regeneration, including bacteria-infected-wound healing. The abuse of antibiotics leads to drug resistance. Recent developments have demonstrated that the delivery of inorganic bactericidal agents in hydrogels can drive the wound healing process; however, this approach is complicated by external light stimuli, cytotoxicity, nondegradability, and sophisticated fabrication. Herein, an inherent antibacterial, bioresorbable hydrogel was developed by the spontaneous self-aggregation of amphiphilic, oxadiazole-group-decorated quaternary ammonium salts (QAS)-conjugated poly(e-caprolactone)-poly(ethylene glycol)-poly(e-caprolactone) (PCEC-QAS) micellar nanoantimicrobials for methicillin-resistant Staphylococcus aureus (MRSA)-infected cutaneous wound healing. The PCEC-QAS hydrogel showed a stable gel state within the temperature range of 5-50 °C and antibacterial efficacy against both Gram-negative and -positive bacteria in vitro and in vivo. Additionally, the PCEC-QAS hydrogel facilitated the cell spreading, proliferation, and migration without cytotoxicity. An in vivo degradation and skin defect healing study suggested the PCEC-QAS hydrogel was totally absorbed without local or systemic toxicity and could promote wound repair in the absence of drugs, cytokines, or cells. Significantly, this hydrogel accelerated the regeneration of a MRSA-infected full-thickness impaired skin wound by successfully reconstructing an intact and thick epidermis similar to normal mouse skin. Collectively, a self-assembling PCEC-QAS antibacterial hydrogel is a promising dressing material to promote skin regeneration and prevent bacterial infection without additional drugs, cells, light irradiation, or delivery systems, providing a simple but effective strategy for treating dermal wounds.

Background Nanocarriers could deliver significantly higher amounts of antigen to antigen-presenting cells (APCs), which have great potential to stimulate humoral and cellular response in cancer immunotherapy. Thereafter, silica solid nanosphere (SiO2) was prepared, and a model antigen (ovalbumin, OVA) was covalently conjugated on the surface of SiO2 to form nanovaccine (OVA@SiO2). And the application of OVA@SiO2 for cancer immunotherapy was evaluated. Materials and methods SiO2 solid nanosphere was prepared by the Stober method, then successively aminated by aminopropyltriethoxysilane and activated with glutaraldehyde. OVA was covalently conjugated on the surface of activated SiO2 to obtain nanovaccine (OVA@SiO2). Dynamic light scattering, scanning electron microscope, and transmission electron microscope were conducted to identify the size distribution, zeta potential and morphology of OVA@SiO2. The OVA loading capacity was investigated by varying glutaraldehyde concentration. The biocompatibility of OVA@SiO2 to DC2.4 and RAW246.7 cells was evaluated by a Cell Counting Kit-8 assay. The uptake of OVA@SiO2 by DC2.4 and its internalization pathway were evaluated in the absence or presence of different inhibitors. The activation and maturation of bone marrow-derived DC cells by OVA@SiO2 were also investigated. Finally, the in vivo transport of OVA@SiO2 and its toxicity to organs were appraised. Results All results indicated the successful covalent conjugation of OVA on the surface of SiO2. The as-prepared OVA@SiO2 possessed high antigen loading capacity, which had good biocompatibility to APCs and major organs. Besides, OVA@SiO2 facilitated antigen uptake by DC2.4 cells and its cytosolic release. Noteworthily, OVA@SiO2 significantly promoted the maturation of dendritic cells and up-regulation of cytokine secretion by co-administration of adjuvant CpG-ODN. Conclusion The as-prepared SiO2 shows promising potential for use as an antigen delivery carrier.

The reconstruction of large cranial bone defects by bioactive materials without exogenous cells or growth factors remains a substantial clinical challenge. Here, synthetic fibrous glycopeptide hydrogel (GR

Titanium alloy has been widely used in orthopedic surgeries as bone defect filling. However, the regeneration of high-quality new bones is limited due to the pro-inflammatory microenvironment around implants, resulting in a high occurrence rate of implant loosening or failure in osteological therapy. In this study, extracellular matrix-mimetic polysaccharide hydrogel co-delivering BMP-2 and interleukin (IL)-4 was composited with 3D printed titanium alloy to promote the osseointegration and regulate macrophage response to create a pro-healing microenvironment in bone defect. Notably, it is discovered from the bioinformatics data that IL-4 and BMP-2 could affect each other through multiple signal pathways to achieve a synergistic effect toward osteogenesis. The composite scaffold significantly promoted the osteoblast differentiation and proliferation of human bone marrow mesenchyme stem cells (hBMSCs). The repair of large-scale femur defect in rat indicated that the dual-cytokine-delivered composite scaffold could manipulate a lower inflammatory level in situ by polarizing macrophages to M2 phenotype, resulting in superior efficacy of mature new bone regeneration over the treatment of native titanium alloy or that with an individual cytokine. Collectively, this work highlights the importance of M2-type macrophages-enriched immune-environment in bone healing. The biomimetic hydrogel–metal implant composite is a versatile and advanced scaffold for accelerating in vivo bone regeneration, holding great promise in treating orthopedic diseases.

Poly(l-lactic acid) (PLLA) scaffolds have been used in regenerative medicine, however, they commonly suffer from low flexibility, restricting their application in the repair and reconstruction of soft tissues. In this study, poly(l-lactide-co-e-caprolactone) (PLCL) copolymers were examined to modulate the elasticity of PLLA with the random presence of CL units in PLLA. Thermodynamic analysis revealed that the introduction of PCL could significantly decrease the melting point and glass transition temperature of PLLA, benefiting the extrusion and printing of PLCL. Diverse scaffolds with designed architectures including porous cubes with or without large holes, cambered plates with holes and round tubes could be easily constructed by 3D printing. In the process of elastic deformation, the maximum elastic stress of the copolymer scaffold was obviously increased from 19.6 to 31.5 MPa when the relative content of PCL was increased to 70%, while the elongation at break was evidently increased from 388% to about 1974%. The Young's modulus of PLCL was also significantly decreased (P < 0.05) in comparison with that of PLLA. PLCL scaffolds have good platelet and endotheliocyte adhesion ability and no obvious hemolysis was observed. In vivo subcutaneous implantation of PLCL scaffolds demonstrated superior biocompatibility. Collectively, this work highlights that copolymerization of PCL segments into PLLA is an effective approach to tune the 3D printability and the stiffness and elasticity of PLLA scaffolds. PLCL scaffolds hold great promise for the regeneration of soft tissues including but not limited to cartilage, myocardium, muscle, tendon and nervous tissues.

The strategy of pH-responsive aggregation in tumor micro-environment (TME) provides an intriguing platform for enhancing tumor retention and exerting therapeutic effects sufficiently. In this work, we have designed an intelligent dual pH-responsive self-aggregating nano gold system (Au@PAH-Pt/DMMA) for the combined chemo-radiotherapy, in which a “charge-reversal like” strategy was utilized to realize irreversible stable aggregation and pH-specific release of cisplatin prodrug in TME. Responsive aggregation increases the cellular uptake of Au@PAH-Pt/DMMA by 55%–60%, and the cellular uptake of Pt after X-ray irradiation can be further enhanced by 80%. Additionally, responsive aggregation greatly slows down the rate of efflux from tumor in vivo. This system not only promotes B16 cell apoptosis as a chemotherapeutic agent (30.4%), it also enhances the effect of chemo-radiotheray (CRT) by promoting apoptosis as a radiosensitizer (55.3%). The colony formation assay results were fitted to cell survival curve of B16 cells and the sensitization enhancement ratio (SER) was calculated to be 1.29, which shows a good radiosensitizing ability. When exposed to X-ray, this nanoplatform reached the ideal therapeutic effect, and the tumor inhibition rate of Au@PAH-Pt/DMMA reached 91.6% with low drug administration frequency and dose of X-ray. Overall, the dual pH-responsive nanoparticles Au@PAH-Pt/DMMA could effectively enhance tumor therapeutic efficiency by combined chemo-radiotherapy, which provides a potential method for clinical transformation of cancer treatment.

Immunotherapy, an attractive option for cancer treatment, necessitates the direct stimulation of immune cells in vivo and the simultaneous effective inhibition of immunosuppressive tumor microenvironments. Methods: In the present study, we developed an injectable PEG-b-poly(L-alanine) hydrogel for co-delivery of a tumor vaccine and dual immune checkpoint inhibitors to increase tumor immunotherapy efficacy. Tumor cell lysates, granulocyte-macrophage colony stimulating factor (GM-CSF), and immune checkpoint inhibitors (anti-CTLA-4/PD-1 antibody) were readily encapsulated in the porous hydrogel during the spontaneous self-assembly of polypeptide in aqueous solution. Results: Sustained release of tumor antigens and GM-CSF persistently recruited and activated dendritic cells (DCs) and induced a strong T-cell response in vivo, which was further enhanced by the immune checkpoint therapy. The hydrogel vaccine also upregulated the production of IgG and the secretion of cytokines including IFN-γ, IL-4, and TNF-α. Importantly, the hydrogel-based combination therapy had superior immunotherapy effects against melanoma and 4T-1 tumor in comparison with the vaccine alone or in addition with a single immune checkpoint blockade. In studying the underlying mechanism, we found that the hydrogel-based combinatorial immunotherapy not only significantly increased the activated effector CD8+ T cells within the spleens and tumors of vaccinated mice, but also reduced the ratio of Tregs. Conclusion: Our findings indicate that the polypeptide hydrogel can be used as an effective sustained delivery platform for vaccines and immune checkpoint inhibitors, providing an advanced combinatorial immunotherapy approach for cancer treatment.

Clinical wound management of radiation-induced skin injury (RSI) remains a great challenge due to acute injuries induced by excessive reactive oxygen species (ROS), and the concomitant repetitive inflammatory microenvironment caused by an imbalance in macrophage homeostasis. Herein, a cutaneous extracellular matrix (ECM)-inspired glycopeptide hydrogel (GK@TA

Background Hepatocellular carcinoma (HCC) is a common cause of cancer-related deaths and has low sensitivity to conventional therapies. Dendritic cell (DC) loaded tumor-exosomes (TEX) have shown antitumor effects in a murine HCC model. However, the combined antitumor efftcts of DC-TEX and programmed death protein 1 antibody (PD-1 Ab) at different time application has not been investigated. Methods In this study, ectopic, orthotopic, and diethylnitrosamine (DENA)-induced HCC models were established and treated with DC-TEX alone or in combination with PD-1 Ab at different time points. Meanwhile, we established an orthotopic HCC model in BALB/C nude mice and restore t cells. Results The results showed that along with the increased number of CD8+ T cells, the PD-1+CD8+ T-cell population was also significantly increased after DC-TEX injection. The number of CD8+ T cells peaked 72 h after DC-TEX injection, and the PD-1+CD8+ T cells also showed a similar result. Subsequently, the PD-1 Ab was applied in combination with DC-TEX at a series of time points (0, 24,72, 96, 120 or 168 h). Surprisingly, the combined treatment showed strong antitumor effects and this effect was most prominent when PD-1 Ab was administerd at 72 h. In vitro, PD-1 Ab also significantly reversed the proliferative ability of PD-1+CD8+ T cells at 72 h. The combined antitumor effects of PD-1 Ab and DC-TEX were mainly through their stimulation on CD8+T cells proliferation as well as repression for T cell exhaustion. Conclusion In conclusion, the combination of DC-TEX and PD-1 Ab significantly suppresses tumor growth in a murine HCC model and that the antitumor effect is affected by the timing of PD-1 Ab treatment.

Nanovaccine can elicit antigen-specific immune responses against tumor cells expressing homologous antigens and has attracted enormous attention in cancer immunotherapy. However, tumor heterogeneity remarkably hinders the development of nanovaccines. Here we demonstrate that PTT-induced in situ vaccination cancer therapy can elicit potent antitumor immunity against disseminated and metastatic tumors. Gold nanorods (AuNRs) covalently coupled with amphiphilic polyTLR7/8a and MMP-2-sensitive R9-PEG conjugate (AuNRs-IMQD-R9-PEG) were developed as a new biocompatible PTT agent with favorable photothermal efficiency and stability. Importantly, AuNRs-IMQD-R9-PEG can effectively absorb tumor-derived protein antigens, forming nanovaccines directly in vivo and enhance the activation of host dendritic cells (DCs), thereby amplifying adaptive antitumor T-cell responses, triggering effector memory immune responses, and activating innate antitumor immunity. Remarkably, peri-tumoral administration of low-dose multifunctional AuNRs followed by non-invasive near-infrared (NIR) laser irradiation enables efficient tandem PTT-vaccination treatment modality that can inhibit local as well as untreated distant and metastatic tumors in mice inoculated with poorly immunogenic, highly metastatic 4T1 tumors. Our findings indicate that AuNRs-IMQD-R9-PEG-mediated in situ cancer vaccination provides a powerful immunotherapy characterized by markedly increased infiltration of effector CD8+ T, natural killer T (NKT) cells in tumors and long-term animal survival, thus, offering a promising therapeutic strategy for advanced, disseminated cancers.

Immunotherapy is revolutionizing cancer treatment. Vaccination of antigenic peptides has been identified as a promising strategy for cancer immunotherapy while insufficient immune responses were stimulated due to low antigenicity. Moreover, immune checkpoint blockade therapy is still limited by a low objective response rate. In this work, cationic polymer-lipid hybrid nanovesicle (P/LNV)-based liposomes are designed to simultaneously deliver tumor vaccines composed of anionic antigen epitopes, toll-like receptor-9 agonist (TLR9), CpG (AE/CpG), and indoleamine-2,3-dioxygenase (IDO) inhibitor, 1-methyl-tryptophan (1-MT), to increase the immunogenicity of peptide antigens and meanwhile block the immune checkpoint. P/LNV liposomes efficiently enhanced the uptake of vaccines by dendritic cells (DCs) and improved the maturation of DCs indicated by the significantly increased percentage of CD86+MHCI+ DCs, resulting in a potent cytotoxic T-lymphocyte (CTL) response against B16-OVA tumor cells in vitro. Importantly, the combination immunotherapy showed significantly higher therapeutic efficiency towards melanoma tumors in mice, compared with an untreated or individual therapy modality. Mechanistically, the co-delivery system could elicit a strong cancer-specific T-cell response, as characterized by the remarkably increased infiltration of CD8+ T cells in the tumor and draining lymph nodes. Altogether, cationic liposomes delivered with tumor vaccines and IDO inhibitor provide a promising platform for cancer immunotherapy by provoking antitumor T-cell immunity and simultaneously reversing the immunosuppressive tumor microenvironment.

Type 1 diabetes (T1D) is an autoimmune subtype of diabetes, mainly caused by the immune attack of self-insulin-producing cells. Immune modulation that delays the onset of T1D is able to reduce diabetic complications and mortality. We have previously reported that mannosylated sodium alginate nanoparticles (MAN-ALG) exhibited excellent dendritic cell targeting and in vivo antigen delivery efficacy. To investigate the role of MAN-ALG in an autoimmune context, we loaded the MAN-ALG with Ins29-23, a T1D autoantigen [MAN-ALG(PEP)], for T1D immune tolerance induction in nonobese diabetic (NOD) mice. We observed the delayed onset of T1D occurrence and some degree of blood glucose reduction accompanied by a larger islet area, attributable to augmented T-regulatory cell proportion in mice treated with MAN-ALG(PEP). However, MAN-ALG was also found to elicit lysosomal escape and cross-presentation of Ins29-23 in bone marrow-derived dendritic cells, leading to the immune activation of Ins29-23-recognizing T cells and destruction of Ins29-23-expressing islet cells. This dual impact resulted in delayed but a nonpreventive effect of MAN-ALG(PEP) on the T1D onset in NOD mice. Considering the potent immune stimulatory property of MAN-ALG, cautions should be implemented when using alginate-based biomaterials in an autoimmune context. Moreover, it is also noted that regarding the in vivo outcome of immune therapies, biomaterial-based delivery systems and their detailed role on immune regulation need to be examined.

Antibacterial hydrogels are attracting extensive attention in soft tissue repair and regeneration, including bacteria-infected-wound healing. The abuse of antibiotics leads to drug resistance. Recent developments have demonstrated that the delivery of inorganic bactericidal agents in hydrogels can drive the wound healing process; however, this approach is complicated by external light stimuli, cytotoxicity, nondegradability, and sophisticated fabrication. Herein, an inherent antibacterial, bioresorbable hydrogel was developed by the spontaneous self-aggregation of amphiphilic, oxadiazole-group-decorated quaternary ammonium salts (QAS)-conjugated poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC-QAS) micellar nanoantimicrobials for methicillin-resistant

Cancer immunotherapy is an important tumor therapy option for prevention and treatment of tumors and has attracted tremendous interests. However, the therapeutic outcomes are limited by insufficient antigen uptake and presentation by antigen-presenting cells such as dendritic cells (DCs). In this study, mannose-functionalized antigen nanoparticles with endosome escape activity were designed for targeted DCs, accelerated endosomal escape and enhanced MHC-I antigen presentation for cancer immunotherapy. Mannose was selected as DCs targeting ligand to enhance antigen uptake. Model antigen ovalbumin (OVA) was directly conjugated with mannose to obtain DCs targeting antigen, which was then complexed with polyethylenimine (PEI) through electrostatic interaction to form mannose-functionalized antigen nanoparticles (MAN-OVA/PEI NPs). Flow cytometry analysis revealed that the MAN-OVA/PEI NPs greatly increased antigen uptake by DCs compared with OVA/PEI NPs. Confocal laser scanning microscopy further demonstrated that MAN-OVA/PEI NPs enhanced cytosolic antigen release. Moreover, MAN-OVA/PEI NPs significantly promoted cytokine production and DCs maturation in vitro. More importantly, MAN-OVA/PEI NPs treated DCs exhibited enhanced cross-presentation to B3Z T cell hybridoma in vitro. This work suggests that mannose-functionalized antigen nanoparticles provide a versatile delivery vehicle for targeted DCs, accelerated endosomal escape and enhanced MHC-I antigen presentation for cancer immunotherapy.

Small diameter vascular grafts have been promising substitutes for bypass surgery to treat cardiovascular disease. However, no ideal product is available in the clinic. In order to design improved, next generation vascular grafts, it is essential to understand the cellular and molecular mechanisms underlying tissue regeneration after vascular graft implantation. Two diverse microenvironments, circulating blood and the surrounding tissue, are involved in the regeneration process after vascular graft implantation in situ. However, their regenerative functions are not completely understood. To elucidate their roles in regeneration, we used electrospinning to fabricate four types of tubular scaffolds with a structure consisting of a microfiber layer (fiber diameter ∼ 6 μm) and a nanofiber layer (fiber diameter < 1 μm): microfiber scaffold, nanofiber scaffold, outer microfiber bilayer scaffold and inner microfiber bilayer scaffold. In the outer microfiber scaffold, cells from the surrounding tissue were allowed into the scaffold but not cells from the circulating blood while it was opposite in the inner microfiber scaffold. The processes of endothelium formation, smooth muscle cell regeneration, neo-tissue formation and vascularization of these scaffolds were analyzed with a rat left common carotid artery replacement model. Our data showed that smooth muscle cells' regeneration and vascularization were different among the four types of scaffolds. The thickest neo-tissue and α-SMA+ cell layers were detected in the microfiber scaffold group while the thinnest in the nanofiber scaffold group, and thicker neo-tissue and α-SMA+ cell layers were found in the outer microfiber bilayer scaffold group compared to the inner microfiber bilayer scaffold group. In addition, vascularization in the outer microfiber bilayer scaffold group and microfiber group was dramatically better than the inner microfiber bilayer scaffold group and the nanofiber group. Furthermore, we demonstrated that the regenerated SMCs were associated with the CD206+ macrophages in the graft wall. In all, the microfiber scaffold showed the best neo-tissue regeneration in vivo. These results indicate that the surrounding tissue contributes more to vascular regeneration than circulating blood. This finding gives a significant design clue that modulating the vascular surrounding tissue will be an alternative strategy for designing advanced and feasible small diameter vascular grafts.

Correction for ‘Guanidinylated cationic nanoparticles as robust protein antigen delivery systems and adjuvants for promoting antigen-specific immune responses in vivo’ by Pan Li et al., J. Mater. Chem. B, 2016, 4, 5608–5620.

Combined chemotherapy and photodynamic therapy (PDT) is a promising strategy to enhance the anticancer efficacy of both drugs via combination effects. In this work, doxorubicin (DOX)-loaded pheophorbide A (PheoA)-modified Pluronic F127 (F127) micelles (DOX/F127-PheoA micelles) were developed for combined chemo-photodynamic therapy of melanoma. DOX/F127-PheoA micelles were characterized in terms of size and size distribution, zeta potential, surface morphology, drug loading efficiency, and drug-releasing properties. It was observed that the DOX/F127-PheoA micelles were spherical, with a mean particle size of 146.5 nm and a zeta potential of -3.2 mV. Confocal laser scanning microscopy showed that DOX/F127-PheoA micelles were internalized by B16 melanoma cells and capable of dual-delivery of both DOX and PheoA into tumor cells. Upon light irradiation, DOX/F127-PheoA micelles could generate reactive oxygen species (ROS) both in vitro and in vivo. The in vitro cytotoxic activity of DOX/F127-PheoA micelles in B16 melanoma cells were evaluated by CCK-8 assay. In vivo antitumor efficacy was also assessed using C57 mice bearing B16 tumors, and the DOX/F127-PheoA micelles were administrated intravenously. Under light irradiation, DOX/F127-PheoA micelles significantly inhibited tumor growth compared with free DOX and DOX/F127-PheoA micelles without light irradiation. The mean tumor growth inhibition rate of DOX/F127-PheoA micelles with light irradiation was 73.5%, compared with 42.3% for DOX/F127-PheoA micelles without light irradiation and 26.5% for free DOX. These results suggest that DOX/F127-PheoA micelles are a versatile and effective drug delivery system for combinational chemo-photodynamic therapy against melanoma.

Dendritic cells (DCs) are increasingly used in cancer vaccines due to their ability to regulate T-cell immunity. Major limitations associated with the present DC adoptive transfer immunotherapy are low cell viability and transient duration of transplanted DCs at the vaccination site and the lack of recruitment of host DCs, leading to unsatisfactory T-cell immune response. Here, we developed a novel vaccine nodule comprising a simple physical mixture of the peptide nanofibrous hydrogel, anti-PD-1 antibodies, DCs, and tumor antigens. Upon subcutaneous injection, the vaccine nodule maintained the viability and biological function including the antigen uptake and maturation of encapsulated DCs and simultaneously recruited a number of host DCs and promoted the drainage of activated DCs to lymph nodes, resulting in enhanced proliferation of antigen-specific splenocytes and provoking potent cellular immune responses. Compared with adoptive transfer of DCs and subcutaneous administration of antigen vaccine, such a vaccine nodule shows superior antitumor immunotherapy efficiency in both prophylactic and therapeutic tumor models including delayed tumor growth and prolonged mice survival due to effective stimulation of antitumor T-cell immunity and increased infiltration of activated CD8

Flexible electronics is booming and attracts considerable interest in monitoring physiological activities and health conditions. The development of human-friend flexible electronics with both excellent human movement monitoring and flexible electrode functions at a wide working range remains highly challenging. Herein, we report a biomimetic double-layered multifunctional flexible electronic device composed of a stretchable, tough elastomer covalently coupled with a conductive, double-network hydrogel for monitoring physiological motions. The introduction of optimal physical crosslinking including hydrogen bond and metal coordination in the covalently cross-linked polyurethane elastomer effectively provides favorable flexibility and stretchability. The elastomer-hydrogel integration (EHI) shows ultra-fast responsiveness (10 ms) and resilience (246 ms) as a skin sensor and could effectively detect diverse muscle and joint movements in a highly sensitive and signal waveform-interpreting manner. Further, such a polymer integration with skin shape-adaptive hydrogel and low contact impedance enables real-time high-quality detection of electrocardiogram (ECG) by serving as flexible electrode compared to commercial Ag/AgCl electrodes, and was successfully applied to measure electrooculogram (EOG) and electromyogram (EMG). EHI-based electrodes were feasible and effective for electroencephalogram (EEG) signal detection in brain-computer interfaces (BCI) system. Altogether, this biomimetic EHI electronic device provides an advanced platform for the design of next-generation flexible healthcare diagnostic monitors and soft robots.

Transplantation of immune cells manipulated in vitro to dictate immune responses in the body is promising in cancer immunotherapy. However, this approach suffers from low cell survival after administration, insufficient cell homing to lymph nodes, and off-target. Here we demonstrate an injectable and self-assembled poly( l -valine) hydrogel as the delivery carrier of cargoes including antigen and immunopotentiator for DCs modulation. Our results indicate the vaccine formulation composed of tumor cell lysates (TCL), TLR3 agonist, poly(I:C) and polypeptide hydrogel can robustly recruit, activate and mature DCs in vitro and in vivo by sustained release of TCL and poly(I:C). Hydrogel as the delivery system significantly improves antigen persistence at the injection site and antigen drainage to lymph nodes. Strikingly, subcutaneous injection of hydrogel-based vaccine formulations in melanoma-bearing mice elicits good antitumor efficiency by evoking strong cytotoxic T-lymphocyte immune response. Hydrogel vaccine significantly promotes the production of CD8+ T cells in draining lymph nodes and tumor infiltrating T-lymphocytes. These findings suggest that in vivo program of DCs by injectable polypeptide hydrogel encapsulated with antigen and immunopentiator is able to direct immune responses against cancer. Our study also implies that such a hydrogel may serve as a multifunctional delivery platform of vaccines.

Long-term evaluation of vascular grafts is an essential step to facilitate clinical translation. In this study, we investigate the long-term performance of a macro-porous poly(ɛ-caprolactone) (PCL) electrospun vascular graft using the rat abdominal artery replacement model. Long-term patency, endothelialization, and smooth muscle cell regeneration were evaluated, as well as calcification and degradation. The data showed that all the grafts remained open and unobstructed. There was no evidence of aneurysm, stenosis, or calcification one year after implantation. Importantly, neo-vessel was regenerated on the luminal surface of the graft, and was composed of a complete endothelial layer and several layers of smooth muscle cells. The neo-vessel showed vascular physiological function, although not as good as that in native blood vessels, likely due to the remaining scaffold fibers. These data indicated that the PCL macro-porous electrospun vascular graft has potential to be an artery substitute for long-term implantation. Also, this work indicates that continued efforts are needed to develop advanced vascular grafts that exhibit the appropriate balance between the regeneration of the neo-vessel and the complete degradation of the graft materials. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1618-1627, 2018.

Rapid endothelialization is a key factor that determines the success of small-diameter vascular grafts as an artery substitute in the treatment of cardiovascular diseases. Aimed to facilitate vascular regeneration, we developed a vascular scaffold loaded with resveratrol, which is a natural compound extracted from plants and showed multifaceted effects in cardiovascular protection. The tubular poly(ε-caprolactone) (PCL) scaffold was prepared by electrospinning with resveratrol in the PCL solution. In vitro assay demonstrated that resveratrol could be released from the scaffolds in a sustained and controlled manner. Cell culture results indicated that the migration of endothelial cells (ECs), nitric oxide production, and the ability of tube formation increased in the resveratrol-containing PCL scaffold groups compared with the PCL control. Meanwhile, the level of tumor necrosis factor (TNF)-α, the main proinflammatory factor secreted from macrophages, was reduced, and the messenger RNA expressions of the M2 macrophage-related genes were increased in the resveratrol-containing group. Further, in vivo implantation was performed by replacing rat abdominal aorta. We observed fast endothelialization and enhanced vascular regeneration in rats with resveratrol-containing scaffolds. The presence of resveratrol also induced a large number of M2 macrophages to infiltrate into the graft wall. Taken together, the incorporation of resveratrol into the PCL grafts enhanced the vascular regeneration by modulation of ECs and macrophages.

The purpose of the present study was to identify an "easy-to-adopt" strategy to enhance immune responses using functionalized alginate (ALG) nanoparticles (MAN-ALG/ALG=OVA NPs), which were prepared by CaCl2 cross-linking of two different types of ALG. The mannose (MAN) modified ALG (MAN-ALG) was used for dendritic cell targeting. The other component, composed of ovalbumin (OVA), a model antigen, is conjugated to ALG (ALG=OVA) via pH sensitive Schiff base bond. Grafting of alginate was demonstrated by FT-IR and 1H NMR, while the morphological structure, particle size, Zeta potential of MAN-ALG/ALG=OVA NPs were measured using TEM and DLS. The OVA releasing behavior of MAN-ALG/ALG=OVA NPs was determined as a function of pH. Antigen uptake was examined by flow cytometry and confocal laser scanning microscopy in vitro using mouse bone marrow dendritic cells (BMDCs). The results showed that MAN-ALG/ALG=OVA NPs facilitated antigen uptake of BMDCs and cytosolic release of the antigen. Significant up-regulation of cytokine secretion and expression levels of the surface co-stimulatory molecules were also observed in MAN-ALG/ALG=OVA NPs-treated BMDCs, compared to free OVA. In vivo bio-distribution study using Cy7 (a near-infrared fluorescence dye) labeled MAN-ALG/ALG=OVA NPs showed efficient in vivo trafficking of the nanoparticles from the injection site to the draining lymph nodes. Moreover, MAN-ALG/ALG=OVA NPs were found to enhance cross-presentation of OVA to B3Z T cell hybridoma in vitro. Subcutaneous administration of MAN-ALG/ALG=OVA NPs also induced major cytotoxic T lymphocytes (CTL) response and inhibition of E.G7 tumor growth in C57BL/6 mice. In summary, we report here that the MAN-ALG/ALG=OVA NPs have the potential as a potent nanovaccine for cancer immunotherapy.