Multi-functional wound dressings based on silicate bioactive materials

Injectable chitosan hydrogels tailored with antibacterial and antioxidant dual functions for regenerative wound healing.

Extrusion bioprinting has been widely used to fabricate complicated and heterogeneous constructs for tissue engineering and regenerative medicine. Despite the remarkable progress acquired so far, the exploration of qualified bioinks is still challenging, mainly due to the conflicting requirements on the printability/shape-fidelity and cell viability. Herein, a new strategy is proposed to formulate a dynamic cross-linked microgel assembly (DC-MA) bioink, which can achieve both high printability/shape-fidelity and high cell viability by strengthening intermicrogel interactions through dynamic covalent bonds while still maintaining the relatively low mechanical modulus of microgels. As a proof-of-concept, microgels are prepared by cross-linking hyaluronic acid modified with methacrylate and phenylboric acid groups (HAMA-PBA) and methacrylated gelatin (GelMA) via droplet-based microfluidics, followed by assembling into DC-MA bioink with a dynamic cross-linker (dopamine-modified hyaluronic acid, HA-DA). As a result, 2D and 3D constructs with high shape-fidelity can be printed without post-treatment, and the encapsulated L929 cells exhibit high cell viability after extrusion. Moreover, the addition of the dynamic cross-linker (HA-DA) also improves the microporosity, tissue-adhesion, and self-healing of the DC-MA bioink, which is very beneficial for tissue engineering and regenerative medicine applications including wound healing. We believe the present work sheds a new light on designing new bioinks for extrusion bioprinting.

Assembling Microgels via Dynamic Cross-Linking Reaction Improves Printability, Microporosity, Tissue-Adhesion, and Self-Healing of Microgel Bioink for Extrusion Bioprinting.

Cellulose nanocrystal/calcium alginate-based porous microspheres for rapid hemostasis and wound healing.

This study shows the effective use of MXene‐based nanomaterials to improve the performance of biocomposite sponges in wound healing. In this way, diverse chitin/MXene composite sponges are fabricated by incorporating MXene‐based nanomaterials with various morphology (accordion‐shaped, intercalated, single‐layer, gold nanoparticles (AuNPs)‐loaded single‐layer) into the network of chitin sponge (CH), which can prevent massive blood losses and promote the healing process of bacterial‐infected wounds. With the addition of MXene‐based nanomaterials, the hemostatic efficacy of CH is enhanced due to the improved hemophilicity and accelerated blood coagulation kinetics. Furthermore, the composite sponges show a predominant antibacterial activity through the synergy between the capture and the photothermal effects. Importantly, the addition of AuNPs to composite sponges further improves hemostatic performance and promotes normal skin cell migration to heal the infected wound, achieving wound closure rates of 84% on day 9. These initial studies expand the applications of MXene‐based nanomaterials in biomedical fields.

MXene‐Enhanced Chitin Composite Sponges with Antibacterial and Hemostatic Activity for Wound Healing

A shape memory and antibacterial cryogel with rapid hemostasis for noncompressible hemorrhage and wound healing

Curcumin-laden amphiphilic chitosan microemulsion with enhanced transdermal delivery, skin compatibility and anti-arthritic activity

Hydrogel-forming microneedle arrays as a technique for transdermal drug delivery show promise as an alternative to traditional drug delivery methods. In this work, hydrogel-forming microneedles have been created with effective, controlled delivery of amoxicillin and vancomycin within comparable therapeutic ranges to that of oral delivered antibiotics. Fabrication using reusable 3D printed master templates enabled quick and low-cost hydrogel microneedle manufacturing through micro-molding. By 3D printing at a tilt angle of 45° the resolution of the microneedle tip was improved by double (from ca. 64 μm down to 23 μm). Amoxicillin and vancomycin were encapsulated within the hydrogel's polymeric network through a unique room temperature swell/deswell drug loading method within minutes, eliminating the need for an external drug reservoir. The hydrogel-forming microneedle mechanical strength was maintained, and successful penetration of porcine skin grafts observed with negligible damage to the needles or surrounding skin morphology. Hydrogel swell rate was tailored by altering the crosslinking density, resulting in controlled antimicrobial release for an applicable delivered dosage. The potent antimicrobial properties of the antibiotic-loaded hydrogel-forming microneedles against both Escherichia coli and Staphylococcus aureus, highlights the beneficial use of hydrogel-forming microneedles towards the minimally invasive transdermal drug delivery of antibiotics. 

Shuxian Li

Papers

A shape memory and antibacterial cryogel with rapid hemostasis for noncompressible hemorrhage and wound healing

Curcumin-laden amphiphilic chitosan microemulsion with enhanced transdermal delivery, skin compatibility and anti-arthritic activity

Antimicrobial releasing hydrogel forming microneedles.