Construction of mPt/ICG-αA nanoparticles with enhanced phototherapeutic activities for multidrug-resistant bacterial eradication and wound healing.

The emergence of multidrug-resistant (MDR) bacterial infections calls for novel strategies for effective bacterial inhibition and wound healing. Phototherapeutic approaches are promising in treating bacterial infection because of their high efficiency, noninvasiveness, and few side effects; however, their antibacterial effect is limited by the formation of biofilms in wounds. Herein, we report novel composite nanoparticles (mPt/ICG-αA NPs) combining mesoporous platinum (mPt) nanoparticles, indocyanine green (ICG) and α-amylase (αA) for combating MDR bacteria and treating wound infection, which integrates a triple bacterial inhibition mechanism arising from the combination of photodynamic therapy (PDT), photothermal therapy (PTT) and α-amylase enzymatic activities.

High-Strength Collagen-Based Composite Films Regulated by Water-Soluble Recombinant Spider Silk Proteins and Water Annealing.

Spider silk has attracted extensive attention in the development of high-performance tissue engineering materials because of its excellent physical properties, biocompatibility, and biodegradability. Although high-molecular-weight recombinant spider silk proteins can be obtained through metabolic engineering of host bacteria, the solubility of the recombinant protein products is always poor. Strong denaturants and organic solvents have thus had to be exploited for their dissolution, and this seriously limits the applications of recombinant spider silk protein-based composite biomaterials.

Enhanced anticoagulant activity of hirudin-i analogue co-expressed with arylsulfotransferase in periplasm of E. coli BL21(DE3).

Hirudin, a blood anticoagulant, is the most potent natural thrombin inhibitor of leech origin. Its application is limited because it is difficult to obtain abundant natural hirudin directly from the leech. Although some bioengineering methods can significantly increase the production of hirudin, the reduced efficacy of recombinant hirudin (rH) remains a critical shortcoming.

Development of tilapia collagen and chitosan composite hydrogels for nanobody delivery.

Recently, injectable hydrogels have shown great potential in cell therapy and drug delivery. They can easily fill in any irregular-shaped defects and remain in desired positions after implantation using minimally invasive strategies. Here, we developed hydrogels prepared from tilapia skin collagen and chitosan (HCC).

The recent progress of tissue adhesives in design strategies, adhesive mechanism and applications.

Tissue adhesives have emerged as an effective method for wound closure and hemostasis in recent decades, due to their ability to bond tissues together, preventing separation from one tissue to another. However, existing tissue adhesives still have several limitations. Tremendous efforts have been invested into developing new tissue adhesives by improving upon existing adhesives through different strategies.

Development and characterization of a photo-cross-linked functionalized type-I collagen (Oreochromis niloticus) and polyethylene glycol diacrylate hydrogel.

Collagen hydrogels have been widely investigated as scaffolds for tissue engineering due to their biocompatibility and capacity to promote cell adhesion. However, insufficient mechanical strength and rapid degradation properties remain the major obstacles for their applications. In the present study, type-I tilapia collagen (TC) was functionalized to form methacrylated tilapia collagen (MATC) by introducing methacrylic acid, developing a photo-cross-linked PEGDA-MATC hydrogel.

Improved Cell Viability and Biocompatibility of Bacterial Cellulose through in Situ Carboxymethylation.

Bacterial cellulose (BC) is a natural product with multiple properties, which has been utilized in tissue engineering. However, cell adhesion and proliferation are reported to be weaker on native BC, providing less support compared to other types of biomaterials, like collagen. To increase the biocompatibility and the medical performance of BC, in situ modification is used to add carboxymethyl group to BC.

A natural in situ fabrication method of functional bacterial cellulose using a microorganism.

The functionalization methods of materials based on bacterial cellulose (BC) mainly focus on the chemical modification or physical coating of fermentation products, which may cause several problems, such as environment pollution, low reaction efficiency and easy loss of functional moieties during application. Here, we develop a modification method utilizing the in situ microbial fermentation method combined with 6-carboxyfluorescein-modified glucose (6CF-Glc) as a substrate using Komagataeibacter sucrofermentans to produce functional BC with a nonnatural characteristic fluorescence. Our results indicate that the microbial synthesis method is more efficient, controllable and environmentally friendly than traditional modification methods.

A thermosensitive RGD-modified hydroxybutyl chitosan hydrogel as a 3D scaffold for BMSCs culture on keloid treatment.

Cell therapy with bone marrow-derived mesenchymal stem cells (BMSCs) is a potential method for many disease treatments, including keloid. In the present study, an Arg-Gly-Asp (RGD) modified hydroxybutyl chitosan (HBC) hydrogel (HBC-RGD) was developed to enhance the adhesion and proliferation of BMSCs within the hydrogel. The successful synthesis of HBC-RGD was confirmed by FTIR and H NMR.

Optimization of the preparation conditions of thermo-sensitive chitosan hydrogel in heterogeneous reaction using response surface methodology.

A thermo-sensitive hydroxybutyl chitosan (HBC) hydrogel was prepared by using 1,2‑butene oxide as an etherification modifying agent. To obtain the maximum yield of HBC, response surface methodology (RSM) was applied to optimize its preparation conditions. Key factors were chosen firstly by Plackett-Burman design (PBD) experiments, such as the concentration of NaOH, the ratio of isopropanol to water and reaction temperature.

The promising indicators of the thermal and mechanical properties of collagen from bass and tilapia: synergistic effects of hydroxyproline and cysteine.

Collagen has been widely documented as one of the most promising and competitive biomaterials for tissue engineering and medical applications. However, the properties of collagen differ from one source to another. In the present study, type I collagen (COL-I) was extracted and purified from the skins of Japanese sea bass (Lateolabrax japonicus) and Nile tilapia (Oreochromis niloticus).

Reinforcement of thermoplastic chitosan hydrogel using chitin whiskers optimized with response surface methodology.

To strengthen the mechanical strength of thermo-sensitive hydroxybutyl chitosan (HBC) hydrogel, chitin whiskers were used as sticker to fabricate reinforced HBC (HBCW) hydrogel by using response surface methodology. Unlike the intrinsic network of HBC hydrogel, HBCW hydrogel showed a laminar shape with firm structure. The preparation condition was optimized by three-factor-three-level Box-Behnken design.

Chitosan-Based Thermo/pH Double Sensitive Hydrogel for Controlled Drug Delivery.

A series of thermo/pH sensitive N-succinyl hydroxybutyl chitosan (NSHBC) hydrogels with different substitution degrees of succinyl are prepared for drug delivery. Rheology analysis shows that the gelation temperature of NSHBC hydrogels is 3.8 °C higher than that of hydroxybutyl chitosan (HBC) hydrogels.

Thermo-responsive hydroxybutyl chitosan hydrogel as artery intervention embolic agent for hemorrhage control.

This work targeted to investigate the potential of thermo-responsive hydroxybutyl chitosan (HBC) hydrogel using as an embolic material for occlusion of selective blood vessels. HBC hydrogel was prepared via an etherification reaction between chitosan (CS) and 1, 2-butene oxide. The hydroxybutyl groups were introduced into CS backbone, which endowed HBC hydrogel with properties of porous structure, favorable hydrophilia and rapid sol-gel interconvertibility.

Tough chitosan hydrogel based on purified regeneration and alkaline solvent as biomaterials for tissue engineering applications.

The chitosan based on purified regeneration could be dissolved in 6wt% aqueous NaOH without freeze-thawing cycles and acetylation processing, and such a solution system was effective and different from other dissolving methods Upon heating, a tough hydrogel was constructed from the chitosan (purified regeneration) alkaline solution. The results of XRD, TEM, SEM and rheology analysis proved that chitosan easily aggregated in the solution and formed a nanofibers network to gelate at elevated temperature and concentration. The merely chitosan hydrogel had a uniform network structure and its (5wt%) compressive fracture stress could reach 0.

The influence of solvent formulations on thermosensitive hydroxybutyl chitosan hydrogel as a potential delivery matrix for cell therapy.

Many cell delivery matrices have been developed due to the low transplantation efficiency of cell therapy. In the present study, thermosensitive hydroxybutyl chitosan (HBC) hydrogels were prepared with different formulations' solvent (Dulbecco's modified eagle's medium/phosphate buffered saline [DMEM/PBS], 0:100, 30:70, 50:50, 70:30, 100:0 [v/v]). Their gelation temperature was raised with DMEM ratio increase (from 9.

Nanoparticles/thermosensitive hydrogel reinforced with chitin whiskers as a wound dressing for treating chronic wounds.

Cutaneous chronic wounds are characterized by impaired wound healing which may lead to infection and even amputation. To surmount this problem, we developed a chitin whisker (CW)/carboxymethyl chitosan nanoparticles (CMCS NPs)/thermosensitive hydroxybutyl chitosan (HBC) composite hydrogel (CW/NPs/HBC-HG) as a wound dressing for treating chronic wounds. Upon introduction of CWs, the composite hydrogel exhibited a significant decrease in gelation temperature and enhanced mechanical properties.

Influence of the graft density of hydrophobic groups on thermo-responsive nanoparticles for anti-cancer drugs delivery.

A series of deoxycholate-chitosan-hydroxybutyl (DAHBCs) with different degrees of substitution (DS) of hydrophobic deoxycholate (DOCA) were successfully synthesized. The lower critical solution temperature (LCST) of various DAHBCs could be adjusted from 35.4°C to 42.

A thermosensitive hydroxybutyl chitosan hydrogel as a potential co-delivery matrix for drugs on keloid inhibition.

Keloid is a kind of unique human fibroproliferative dermal disease, and there are still no optimal treatment methods for it. In the present study, a thermosensitive hydroxybutyl chitosan (HBC) hydrogel as a co-delivery matrix for 5-fluorouracil (5-FU) and dexamethasone sodium phosphate (DEXSP) in keloid treatment was developed. The gelation temperature of the HBC hydrogel was observed to be 25.

Chitosan based nanoparticles as protein carriers for efficient oral antigen delivery.

This study aimed to investigate the efficacy of nanoparticles based on chitosan as a vehicle for oral antigen delivery in fish vaccination. Carboxymethyl chitosan/chitosan nanoparticles (CMCS/CS-NPs) loaded extracellular products (ECPs) of Vibrio anguillarum were successfully developed by ionic gelation method. The prepared ECPs-loaded CMCS/CS-NPs were characterized for various parameters including morphology, particle size (312±7.

Immobilization of coacervate microcapsules in multilayer sodium alginate beads for efficient oral anticancer drug delivery.

We have designed and evaluated coacervate microcapsules-immobilized multilayer sodium alginate beads (CMs-M-ALG-Beads) for oral drug delivery. The CMs-M-ALG-Beads were prepared by immobilization of doxorubicin hydrochloride (DOX) loaded chitosan/carboxymethyl coacervate microcapsules (DOX:CS/CMCS-CMs) in the core and layers of the multilayer sodium alginate beads. The obtained CMs-M-ALG-beads exhibited layer-by-layer structure and rough surface with many nanoscale particles.

Preparation and characterization of a novel thermosensitive nanoparticle for drug delivery in combined hyperthermia and chemotherapy.

In the present research, a novel thermal sensitive amphiphilic polymer was synthesized by modification of chitosan with hydrophilic hydroxybutyl groups and hydrophobic deoxycholic acid moieties. By finetuning the hydrophobic/hydrophilic balance of deoxycholic acid decorated hydroxybutyl chitosan (DAHBC), the lower critical solution temperature (LCST) of this novel polymer could be adjusted to 38.2 °C, which is an appropriate temperature in hyperthermia therapy.