Integrated wound care, a sequential process of promoting wound hemostasis, sealing, and healing, is of great clinical significance. However, the wet environment of wounds poses formidable challenges for integrated care. Herein, we developed an epidermal growth factor (EGF)-loaded, dehydrated physical microgel (DPM)-formed adhesive hydrogel for the integrated care of wet wounds. The DPMs were designed using the rational combination of hygroscopicity and reversible crosslinking of physical hydrogels. Unlike regular bioadhesives, which consider interfacial water as a barrier to adhesion, DPMs utilize water to form desirable adhesive structures. The hygroscopicity allowed the DPMs to absorb interfacial water and subsequently, the interfacial adhesion was realized by the interactions between tissue and DPMs. The reversible crosslinks further enabled DPMs to integrate into hydrogels (DPM-Gels), thus achieving wet adhesion. Importantly, the water-absorbing gelation mode of DPMs enabled facile loading of biologically active EGF to promote wound healing. We demonstrated that the DPM-Gels possessed wet tissue adhesive performance, with about 40 times the wet adhesive strength of fibrin glue and about 4 times the burst pressure of human blood pressure. Upon application at the injury site, the EGF-loaded DPM-Gels sequentially promoted efficient wound hemostasis, stable sealing, and quick healing, achieving integrated care of wet wounds.

Integrated wound care through sequentially promoting hemostasis, sealing, and healing holds great promise in clinical practice. However, it remains challenging for regular bioadhesives to achieve integrated care of dynamic wounds due to the difficulties in adapting to dynamic mechanical and wet wound environments. Herein, we reported a type of dehydrated, physical double crosslinked microgels (DPDMs) which were capable of in situ forming highly stretchable, compressible and tissue-adhesive hydrogels for integrated care of dynamic wounds. The DPDMs were designed by the rational integration of the reversible crosslinks and double crosslinks into micronized gels. The reversible physical crosslinks enabled the DPDMs to integrate together, and the double crosslinked characteristics further strengthen the formed macroscopical networks (DPDM-Gels). We demonstrated that the DPDM-Gels simultaneously possess outstanding tensile (∼940 kJ/m3) and compressive (∼270 kJ/m3) toughness, commercial bioadhesives-comparable tissue-adhesive strength, together with stable performance under hundreds of deformations. In vivo results further revealed that the DPDM-Gels could effectively stop bleeding in various bleeding models, even in an actual dynamic environment, and enable the integrated care of dynamic skin wounds. On the basis of the remarkable mechanical and appropriate adhesive properties, together with impressive integrated care capacities, the DPDM-Gels may provide a new approach for the smart care of dynamic wounds. STATEMENT OF SIGNIFICANCE: Integrated care of dynamic wounds holds great significance in clinical practice. However, the dynamic and wet wound environments pose great challenges for existing hydrogels to achieve it. This work developed robust adhesive hydrogels for integrated care of dynamic wounds by designing dehydrated, physical double crosslinked microgels (DPDMs). The reversible and double crosslinks enabled DPDMs to integrate into macroscopic hydrogels with high mechanical properties, appropriate adhesive strength and stable performance under hundreds of external deformations. Upon application at the injury site, DPDM-Gels efficiently stopped bleeding, even in an actual dynamic environment and showed effectiveness in integrated care of dynamic wounds. With the fascinating properties, DPDMs may become an effective tool for smart wound care.

Hydrogels with injectability and robustness have great promise in clinical practice. However, current injectable hydrogels are usually mechanically weak. Here, an idea, “preformed hydrogel reversion”, is proposed to develop robust injectable hydrogels through an intermediate unit‐mediated, continuous structural inheritance strategy. In this strategy, robust preformed hydrogels are physically disassembled into intermediate injectable structure‐inherited microgels (SIMs), and upon encountering water in physiological environment, the SIMs can construct a macroscopical robust structure with the driving force of hydrogen bonds (H‐bonds). The physical disassembly and construction process enables the inheritance of robust structures through SIMs, thereby realizing both excellent injectability and robustness. Beyond that, the SIMs also exhibit long‐term storage stability and convenient usability. Using protein drug loading and hemostasis as examples, it is demonstrated that the SIM system shows superiorities in biomedical applications. The proposed idea of “preformed hydrogel reversion” can open new horizons for developing robust injectable hydrogels for diverse applications.

Enzymatic nanoreactors have shown great potential in cancer therapy due to their delighted anticancer results. Synthesizing biocompatible and highly active nanoreactors on a large scale is demanded in clinic translation. Herein, the therapeutic enzymatic nanoreactors with the structure of biocompatible micromaterials covered on enzymes were constructed in the millifluidic device. The results indicated that the nanoreactors were successfully synthesized in the droplet-flow millifluidic device for the first time and had high bio-safety even without postprocessing. The nanoreactors could be internalized by cancer cells and possessed long blood circulation time in vivo (t1/2 = 25 h). Moreover, mild synthetic conditions and minimized synthesis pathway empowered nanoreactors with favorable catalytic activity about 96.5% +/- 3.9% of native enzymes. Furthermore, enzymatic nanoreactors loaded with glucose oxidase presented a strong anticancer effect and low systemic toxicity. In summary, the assay provides a facile and promising strategy for synthesizing highly active nanoreactors on a large scale.

High-strength hydrogels formed in situ through a convenient gel transition process are highly desirable for emergency treatment due to their ability to quickly respond to accidents. However, current in-situ formed hydrogels require a laborious precursor preparation process or lack sufficient mechanical strength. Herein, we reported a series of microgels that were capable of convenient in-situ transition to high-strength hydrogels from their easily portable form, thereby facilitating emergency treatment. Three kinds of microgels were derived from two types of hydrogen bonds (H-bonds; OH⋯OC, NH⋯OC) crosslinked preformed hydrogels, and all exhibited excellent stability when stored at room temperature. After mixing with water, all these microgels could undergo a quick hydration process and then transform into high-strength hydrogels in situ through H-bonds. Specifically, stronger H-bond crosslinked microgels could build hydrogels with higher mechanical strength, albeit at the cost of longer hydration and operation time. Nevertheless, the whole operation process could be finished within several minutes, and the resultant hydrogels could exhibit maximally megapascal-level compressive strength and tens of kilopascal storage modulus. In the comparison of emergency application performance with commercial chitosan hemostatic powder (CHP), we found that the microgels could stop accidental bleeding almost immediately, and the whole process from taking out the stored microgels to hemostasis could be completed within 15 s, which was superior to CHP. Overall, the results indicated that the in-situ formed microgel-based hydrogels with convenient gel-transition ability and high strength showed great potential in emergency treatments.

Liposomes have been developed as drug delivery carriers to enhance the antitumor efficiency of therapeutic agents. Lipusu® (Lip), a paclitaxel (PTX) liposome, has been widely used in the treatment of breast cancer. Compared with PTX, Lip could change the biodistribution and reduce the systemic toxicity. However, there was no positive effect on the entry of PTX into tumor cells, and thus the therapeutic effect was not significantly improved. Therefore, it is meaningful to engineer Lip for improving tumor cellular uptake efficiency. Here, lysophosphatidylcholine (LPC)-engineered Lip (LPC-Lip) was constructed via inserting single chain lipid tails into liposomal lipid bilayers, which was realized by simple incubation. Compared with Lip, the better cellular uptake of liposomes modified with LPC resulted in enhanced cytotoxic activity of LPC-Lip in 4T1 cells. Furthermore, stronger tumor growth inhibition was observed in LPC-Lip treated 4T1 tumor-bearing mice without significant side effects. In conclusion, by modulating the lipid composition of Lip, the antitumor efficacy can be improved, and LPC engineered Lip may serve as a promising formulation of PTX for future cancer therapy.

The excellent biocompatibility drug delivery system for effective treatment of glioma is still greatly challenged by the existence of blood-brain barrier, blood-brain tumor barrier, and the tissue toxicity caused by chemotherapy drugs. In this study, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) is used for the first time for modifying third-generation poly(amidoamine) (PAMAM) to enhance their brain tumor-targeted drug delivery ability as well as simultaneously reducing the toxicity of PAMAM dendrimers and the tissue toxicity of the loaded doxorubicin (DOX). The cytotoxicity, the therapeutic ability in vitro, and the brain tumor-targeted ability of the PMPC modified PAMAM nanoparticles are further studied. Results indicate that PMPC, as a dual-functional modifier, can significantly reduce the cytotoxicity of PAMAM dendrimers, while efficiently target the brain tumor. In addition, the therapeutic effect of DOX-loaded PAMAM-PMPC in mice inoculated with U-87 is also studied in vivo. In comparison with DOX solution, DOX-loaded PAMAM-PMPC alleviates weight loss of tumor-inoculated mice and reduces the cardiotoxicity of DOX. The tumor growth inhibition, in vivo, is significantly increased up to (80.76 ± 1.66)%. In conclusion, this strategy of PMPC dual-functional targeted nanocarrier provides a new method for the delivery of chemotherapeutic drugs to treat glioma.

Spherical nanocelluloses, also known as cellulose nanospheres (CNS), have controllable morphology and have shown advantages as green template material, emulsion stabilizer. Herein, CNS were prepared via a new two-step method, first pretreatment of microcrystalline cellulose (MCC) using ZnCl2·3H2O and then acid hydrolysis of regenerated cellulose (RC) via p-toluenesulfonic acid (p-TsOH). The shape, size, crystallinity of MCC were changed, and nubbly RC with smallest size (942 nm) was obtained after 2 h pretreatment by ZnCl2·3H2O. CNS with high 61.3% yield were produced after acid hydrolysis (67 wt% p-TsOH) of RC at 80 °C, 6 h. The analysis of Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) showed that CNS had an average diameter of 347 nm. CNS were present in precipitate after high-speed centrifugation, due to the high Zeta potential of −12 mV and large size. The structure of CNS was tested by Fourier Transfer Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Nuclear Magnetic Resonance (NMR), CNS had high crystallinity (cellulose II) of 61%. Thermal Gravimetric Analysis (TGA) indicated that CNS had high thermal stability (Tonset 303.3 °C, Tmax 332 °C). CNS showed poor re-dispersibility in water/ethanol/THF, 1 wt% CNS could be dissolved in ZnCl2·3H2O. 7.37% rod-like CNC were obtained after 6 h hydrolysis. FTIR proved that p-TsOH was recovered by re-crystallization. This study provided a novel, sustainable two-step method for the preparation of spherical CNS.

Exosomes derived from non-tumor cells hold great potential as drug delivery vehicles because of their good biosafety and natural transference of bioactive cargo between cells. However, compared to tumor-derived exosomes, efficient delivery is limited by their weak interactions with tumor cells. It is essential to engineer exosomes that improve tumor cellular internalization efficiency. A simple and effective strategy to enhance tumor cell uptake by engineering the exosome membrane lipids can be established by drawing on the role of lipids in tumor exosomes interacting with tumor cells. Amphiphilic phosphatidylcholine (PC) molecules are inserted into the membrane lipid layer of reticulocyte-derived exosomes (Exos) by simple incubation to construct PC-engineered exosomes (PC-Exos). It is demonstrated that PC-Exos showed significantly enhanced tumor cell internalization and uptake rate compared to native Exos, up to a twofold increase. After therapeutic agent loading, PC-Exos remarkably promotes intracellular drug or RNA accumulation in cancer cells, thus showing enhanced in vitro anti-tumor activity. This work demonstrates the crucial role of engineering exosomal lipids in modulating cancer cellular uptake, which may shed light on the design of high-efficiency exosome-based drug delivery carriers.

Regulating biological events by releasing bioactive molecules in accordance with the natural repair process is recognized to enable to promote the repair process. To this end, a novel hydrogel delivery system that can respond to the bone fracture microenvironment signal to timingly and sequentially release bioactive molecules was designed for the first time. The hydrogel system was synthesized by Michael addition reaction via maleimide-end-capped eight-armed poly (ethylene glycol) (8-arm-PEG-Mal) and matrix metalloproteinases-7 (MMP7) sensitive peptides. Nanoparticles developed previously by us were employed here to encapsulate the cargoes and release them once taken by cells. One type of cargo-loaded nanoparticles was embedded into the hydrogel through physical embedding, while the other was modified by MMP7 sensitive peptides followed by covalently bonding into the hydrogel. The results showed that 80% of physically embedded nanoparticles could be released in the first three days. Once MMP7 appeared after three days according to the natural regeneration process, the chemically bonded nanoparticles were released sharply along with hydrogel degradation, and the cumulative release could reach 100%. In addition, the hydrogel system was applied to release microRNA (miRNA)-loaded nanoparticles to identify its timing sequential release effect. It was also confirmed that the nanoparticles discharged could be taken by macrophages to further regulate their behaviors in the future. Overall, this release system realized the delivery of different cargoes in an accurate and timing sequential way according to the natural principle of bone reconstruction, providing a new design strategy of drug delivery system for accelerating bone tissue repair.

Ischemic stroke is an acute and severe neurological disease, which leads to disability and death.Immunomodulatory therapies exert multiple remarkable protective effects during ischemic stroke.However, patients suffering from ischemic stroke do not benefit from immunomodulatory therapies due to the presence of the blood-brain barrier (BBB) and their off-target effects.Methods: We presented a delivery strategy to optimize immunomodulatory therapies by facilitating BBB penetration and selectively delivering intravenous immunoglobulin (IVIg) to ischemic regions using 2-methacryloyloxyethyl phosphorylcholine (MPC)-nanocapsules, MPC-n(IVIg), synthesized using MPC monomers and ethylene glycol dimethyl acrylate (EGDMA) crosslinker via in situ polymerization.In vitro and in vivo experiments verify the effect and safety of MPC-n(IVIg).Results: MPC-n(IVIg) efficiently crosses the BBB and IVIg selectively accumulates in ischemic areas in a high-affinity choline transporter 1 (ChT1)-overexpression dependent manner via endothelial cells in ischemic areas.Moreover, earlier administration of MPC-n(IVIg) more efficiently deliver IVIg to ischemic areas.Furthermore, the early administration of low-dosage MPC-n(IVIg) decreases neurological deficits and mortality by suppressing stroke-induced inflammation in the middle cerebral artery occlusion model. Conclusion:Our findings indicate a promising strategy to efficiently deliver the therapeutics to the ischemic target brain tissue and lower the effective dose of therapeutic drugs for treating ischemic strokes.

Mussel-inspired, coordinate-crosslinked gels have attracted extensive attention but their adhesive behaviors are still not fully understood. Herein, four mussel-inspired molecules with different molecular characteristics are synthesized to study their adhesive behaviors. It is demonstrated that their adhesive behaviors are dependent on the environments. For these mussel-inspired molecules, physiological environment containing relatively low Fe3+ contents is appropriate for achieving high adhesive strength. In addition, the mussel-inspired molecules with positive charge, high molecular weight, or high catechol substitute ratio benefited for improving adhesive strength, however, only in the appropriate environment. In the inappropriate environments (physiological pH, high Fe3+ contents), the adhesives show similar low adhesive strength. These environment-dependent adhesive behaviors are due to the poor interfacial adhesive capacity of the adhesives formed in the inappropriate environments. The study uncovers the adhesive behaviors of mussel-inspired coordinate-crosslinked gels and thus may further provide valuable evidences in the design of metal-crosslinked bioadhesives.

Features of rapid loss and inadequate bone mass of alveolar bone after teeth extraction are still great obstacles for a successful subsequential dental implantation. MicroRNA-based therapy, though an advantageous strategy in tissue regeneration, is still not available for alveolar bone due to the unique complicated oral environment which is full of enzymes and electrolytes. In this paper, a microRNA-activated scaffold constituted of microRNA21 nanoparticles combined with porous Bio-Oss particles was designed for the use of accelerating the early stage healing of the alveolar bone. It was noteworthy that the regeneration of alveolar bone was rapidly promoted to be shortened from the ordinary 3 months to 2 weeks. The nanoparticles designed by us according to the oral environment could protect microRNA from various enzymes and electrolytes attack, leading to a steady, continuous, and efficient delivery of gene. With the aid of porous Bio-Oss, microRNA-21 released in situ and its effects on highly reducing the recovery time and improving the quality of newly formed bone at the alveolar site were confirmed for the first time. Great potential could be seen for the microRNA-mediated biofunctionalized scaffold on the future dental application.

Most existing bioadhesives, even those showing superiority in wound closure effectiveness, do not assist in the post‐wound closure process. A bioinspired, in situ formed, double‐dynamic‐bond crosslinked hydrogel bioadhesive that is capable of efficiently closing open wounds and enabling post‐wound closure care is reported. Catechol‐modified ε‐poly‐ l ‐lysine and oxidized dextran are employed as natural polymer backbones and they are in situ crosslinked using Schiff's base dynamic bond and catecholFe coordinate dynamic bond through a process inspired by that used to cure marine mussel glue, forming a hydrogel bioadhesive. The unique double‐dynamic‐bond crosslinked structure endows the bioadhesive with higher mechanical and adhesive strength while retaining quick dissociation and good self‐healing capacities. Accordingly, the bioadhesive can exhibit multiple desirable functions, such as dissolution on demand, repeatable adhesiveness, adhesive and mechanical strength sufficient for wound closure, injectability, and good biocompatibility (DREAMING). After efficiently closing skin incisions, the bioadhesive can be facilely removed or repeatedly close the reopened wounds, thus enabling post‐wound closure care. On the basis of favorable functions in wound closure and the ability to enable post‐wound closure care, the bioadhesive demonstrates great potential in dealing with skin wounds.

The aim of this study was to investigate the effect of melatonin (MT) and its metabolite N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) on Alzheimer-like learning and memory impairment in rats intracerebroventricularly injected with streptozotocin (STZ). The results showed that the escape latency of the STZ group was longer than that of the control (CON), MT, and AFMK groups. Increased levels of hyperphosphorylated tau, neurofilament proteins, and malondialdehyde and decreased superoxide dismutase levels were observed in the brains of the rats from the STZ group compared with the brains of the rats from the CON, MT, AFMK high and low group. These results suggest that exogenous MT and AFMK can improve memory impairment and downregulate AD-like hyperphosphorylation induced by STZ, most likely through their antioxidation function. Meanwhile, we found that an equal dose of AFMK had a stronger effect than that of MT. Our results indicate that MT and its metabolite AFMK represent novel treatment strategies for Alzheimer's disease.

Strong glue of mussels has long been considered as an ideal model to design synthetic bio-adhesives but the adhesive strength of metal-crosslinked mussel-inspired glues is not often satisfactory. Herein, inspired by the adhesive environment of mussels, we obtained metal-crosslinked ε-poly-L-lysine adhesives with high adhesive performance by introducing the elements of suitable adhesive environment (SAE) into the adhesives. The elements of SAE were clarified as weak alkaline conditions (pH ∼ 7.4) and low Fe3+ contents. The adhesive strength (∼105 kPa) of the metal-crosslinked adhesives endowed with the elements of SAE (PL-Cat/Fe-SAE) was about 8 times higher than that of fibrin glues. The high adhesive strength was found to originate from distinctive interfacial adhesion and cohesion strength of PL-Cat/Fe-SAE. PL-Cat/Fe-SAE showed strong interfacial adhesion capacity and nearly comparable cohesion strength to those PL-Cat/Fe adhesives with higher Fe3+ contents. The nearly comparable cohesion strength of PL-Cat/Fe-SAE was then found to be due to more amount of stable tris-complex existed in PL-Cat/Fe-SAE. In addition, PL-Cat/Fe-SAE was able to efficiently close the full thickness skin incisions. The study highlighted the importance of introducing SAE elements into the design of tissue adhesives and provided a facile and efficient strategy for constructing tissue adhesives with high adhesive performance.

In the natural process of bone repair, matricryptic peptides were activated by up-regulated ECM-degrading enzymes and properly released at bone injury sites, which plays critical roles in bone self-healing. Inspired by this natural process, here, matricryptic peptide-inspired (MPI) hydrogels were designed to promote osteogenic differentiation. MPI hydrogels can be degraded by enzymes and during this time, the masked bioactive components were released to promote osteogenic differentiation. These MPI hydrogels which normally serve as structural support for cell proliferation while promote osteogenic differentiation using embedded osteogenic BFP-1 peptides after degradation may provide a novel design for bone regeneration materials. [GRAPHICS] .

Precise delivery of extracellularly functional protein drugs is limited by the drawback in that the protective carrier often causes undesirable cellular uptake of these therapeutic agents. Here, the design of a weakly cell‐interacted, nanosized, environment‐responsive vehicle (WINNER) with rational phosphorylcholine (PC) surface filling ratios capable of precise extracellular delivery of therapeutic agents for enhanced tumor suppression is reported. Highly hydrophilic zwitterionic PC and enzyme‐responsive peptides are engineered into the functional shell of WINNER which reasonably covers the inner protein. It is demonstrated that rationally controlled PC surface filling ratios (50.5–58.3%) are necessary for weakening interactions between the cell and WINNER whilst providing enough sites on WINNER for enzyme recognition. Consequently, WINNER (50.5–58.3%) can protect inner cargos from cellular uptake and undergo enzymatic degradation, resulting in precise extracellular release of inner protein, such as therapeutic monoclonal antibody (mAb). After intravenous administration, therapeutic mAb nimotuzumab‐loaded WINNER (51.2%) shows highest in vivo antitumor activity compared with free nimotuzumab or nimotuzumab‐loaded PC‐free nanocarrier in a lung adenocarcinoma xenograft tumor animal model. This work presents a simple and flexible approach to design precise extracellular delivery platform which can uncage the therapeutic power of extracellular targeting therapeutic agents.

Biological safety and stable sustained-release of the drug are two crucial issues involved in the formulation of paclitaxel. Focusing on these issues, by using the FDA approved polylactide as carrier material, soybean lecithin as surfactant and maltodextrin as thickener, paclitaxel loaded PLA microspheres were simply prepared by solvent evaporation, thus guaranteeing the biological safety. The introduction of maltodextrin as a thickener aided to a stable sustained-release of paclitaxel. Surface morphology, particle size, drug loading rate, encapsulation efficiency and in vitro drug release behavior were investigated. Biological safety evaluations such as acute toxicity, allergies, hemolysis, skin stimulation and genotoxicity test were also carried out. Results showed that the obtained microspheres were biocompatible and could release paclitaxel at a desirable constant rate. Therefore, the simply prepared paclitaxel formulation with good biological safety and desirable release behavior exhibited great potential of local injection of paclitaxel for the clinical use in the future.

Protein nanocapsules have been demonstrated to be an intracellular protein platform for protein drug delivery. However, traditional production techniques of nanocapsules are not quite suitable for obtaining high protein load efficiency and uniformity of the nanocapsules because of their existing difficulties in homogeneously mixing nanocapsule precursors and heat transfer. Herein, we report a simple way to produce protein nanocapsules using a low cost, easy-to-use millifluidic device that we designed to improve the protein load efficiency as well as the uniformity of the nanocapsules while maintaining the bioactivity of their inner protein and good biocompatibility. The synthesized nanocapsules were carefully characterized and the biocompatibility of these nanocapsules was verified. Besides, acute toxicity test, blood compatibility assay and vascular stimulation test were performed to prepare for clinical applications in the future. The results showed that the nanocapsules synthesized by the device were about 18 nm in size and had a higher protein load efficiency as well as a narrower size distribution (PDI: 0.343) than those of the nanocapsules synthesized by the commonly used bulk mixing method. Moreover, these nanocapsules can well ensure the functions of their inner protein and have high biocompatibility. In short, with our elaborately designed millifluidic device, we provide an alternative way to synthesize high-quality protein nanocapsules.