A polyphenol and ε-polylysine functionalized bacterial cellulose/PVA multifunctional hydrogel for wound healing.

Hydrogels for wound dressings have recently attracted considerable attention in the field of biomedical materials. Developing hydrogel dressings with multiple functions, including good antibacterial, mechanical and adhesive properties, to enhance wound regeneration is significant for clinical applications. To this end, a novel hydrogel wound dressing (PB-EPL/TA@BC) was developed, which was prepared by incorporating bacterial cellulose (BC) modified with tannic acid and ε-polylysine (EPL) into a PVA and borax matrix through a simple method without introducing any other chemical reagents. The hydrogel exhibited good adhesion (8.8 ± 0.2 kPa) to porcine skin, and the mechanical properties were significantly improved after adding BC. Meanwhile, it showed good inhibition against Escherichia coli, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (84.1 ± 2.6 %, 86.0 ± 2.3 % and 80.7 ± 4.5 %) in vitro and Methicillin-resistant Staphylococcus aureus (MRSA) in vivo without the use of antibiotics, ensuring that the process of wound repair with a sterile environment. The hydrogel also presented good cytocompatibility and biocompatibility and could achieve hemostasis within 120 s. The in vivo experiments indicated that hydrogel could not only instantly complete hemostasis of the injured liver models but also obviously promote wound healing in a full-thickness skin. Furthermore, the hydrogel accelerated wound healing process by reducing inflammation promoting collagen deposition compared with commercial Tegaderm™ films. Therefore, the hydrogel is a promising high-end dressing material for wound hemostasis and repair for to enhance the wound healing.

Antibacterial, hemostasis, adhesive, self-healing polysaccharides-based composite hydrogel wound dressing for the prevention and treatment of postoperative adhesion.

Herein, we fabricated novel self-healing, in situ injectable, biodegradable, and non-toxic hydrogels anti-adhesion barrier materials composed of N, O-carboxymethyl chitosan (N,O-CS) and oxidized dextran (ODA) without requiring any chemical cross-linking agent or external stimuli triggers for the prevention and treatment of post-operative peritoneal adhesions. The N,O-CS/ODA hydrogels have a good suitable gelation time, good cytocompatibility and hemocompatibility, good antibacterial activity, excellent biodegradable and biocompatible, and can effectively inhibit the adhesion of fibroblasts to the wound, thereby suggesting that N,O-CS/ODA hydrogels are suitable for preventing post-operative adhesion. Meanwhile, a rat injury sidewall-cecum abrasion model is developed to investigate the efficacy of these hydrogels in achieving post-operative anti-adhesion. A significant reduction of peritoneal adhesions (10% rat with lower score adhesion) is observed in the N,O-CS/ODA-hydrogel-treated group compared with the commercial hydrogel and control groups. These results demonstrated that N,O-CS/ODA hydrogel could effectively prevent post-operative peritoneal adhesion without side effects. Therefore, the N,O-CS/ODA hydrogels with multi-functional properties exhibit great potential for the prevention and treatment of postoperative adhesion.

Facile synthesis of a carbon dots and silver nanoparticles (CDs/AgNPs) composite for antibacterial application.

Bacterial infections can seriously harm human health, and the overuse of traditional antibiotics and antibacterial agents will increase the resistance of bacteria. Therefore, it is necessary to prepare a new kind of antibacterial material. In this work, a carbon dots and silver nanoparticles (CDs/AgNPs) composite has been synthesized in a one-step facile method without the introduction of toxic chemicals, wherein CDs could serve as a reducing and stabilizing agent. The CDs/AgNPs composite was characterized by UV-vis spectrophotometry, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM), which demonstrate that the silver nanoparticles were successfully synthesized in the composite. The zeta potential of the CDs/AgNPs composite was -15.3 mV, indicating that the composite possesses high stability. Furthermore, the composite also exhibited biocidal effects for both Gram-negative E. coli bacteria and Gram-positive S. aureus bacteria. Thus, the composite is considered to be of great potential in bactericidal and biomedical applications.

Injectable, self-healing, antibacterial, and hemostatic N,O-carboxymethyl chitosan/oxidized chondroitin sulfate composite hydrogel for wound dressing.

Biodegradable and injectable hydrogels derived from natural polysaccharides have attracted extensive attention in biomedical applications due to their minimal invasiveness and ability to accommodate the irregular wound surfaces. In this work, we report the development of an in-situ-injectable, self-healing, antibacterial, hemostatic, and biocompatible hydrogel derived from the hybrid of N,O-carboxymethyl chitosan (N,O-CMC) and oxidized chondroitin sulfate (OCS), which did not require any chemical crosslinking. The N,O-CMC/OCS hydrogel could be readily produced under physiological conditions by varying the N,O-CMC-to-OCS ratio, relying on the Schiff base reaction between the -NH- functional groups of N,O-CMC and the -CHO functional groups of OCS. The results showed that the N,O-CMC2/OCS1 hydrogel had relatively long gelation time (133 s) and stable performances. The viability of NIH/3T3 cells and endothelial cells cultured with the N,O-CMC2/OCS1 hydrogel extract was roughly 85%, which demonstrated its low cell toxicity. Besides, the N,O-CMC2/OCS1 hydrogel revealed excellent antibacterial properties due to the inherent antibacterial ability of N,O-CMC. Importantly, the hydrogel tightly adhered to the biological tissue and demonstrated excellent in vivo hemostatic performance. Our work describing an injectable, self-healing, antibacterial, and hemostatic hydrogel derived from polysaccharides will likely hold good potential in serving as an enabling wound dressing material.

The preparation and characterization of a carbon fiber-reinforced epoxy resin and EPDM composite using the co-curing method.

Due to the development of the aerospace technology, the requirements for composite materials have become stricter. Thus, in this work, a completely novel technology, which has not been reported elsewhere, was used to prepare a composite of a carbon fiber-reinforced epoxy resin (CFRP) and ethylene-propylene-diene rubber (EPDM), which was denoted as CFRP/EPDM; CFRP and EPDM are commonly used as a shell and heat insulation layer, respectively, in the solid rocket industry. The composite system had good adhesive ability, as confirmed by the 90° peel strength test, even though the EPDM rubber is non-polar in nature. Additionally, the adhesive mechanism between CFRP and EPDM was determined using scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) indicated that the T d10% value of the CFRP/EDPM composite was slightly higher than that of CFRP. According to the nuclear magnetic resonance (NMR) spectroscopy results of the EPDM rubber and the interlaminar shear strength (ILSS) of CFRP, we can conclude that the co-curing method will not damage the properties of CFRP and EPDM.

Manufacturing and physical characterization of absorbable oxidized regenerated cellulose braided surgical sutures.

Suture is an important part of surgical operation, and closure of the wound associated with this procedure continuous to be a challenge in postoperative care. Currently, oxidized regenerated cellulose (ORC) is widely used in the absorption of hemostatic materials. However, there is no ORC medical suture product in the market. The objective of this article was to prepare novel braided sutures by TEMPO-mediated oxidation regenerated cellulose (TORC) to achieve a suturable material with biodegradability and ideal mechanical properties. Regenerated cellulose (RC) strands were made into sutures on a circular braiding machine, and TEMPO-mediated oxidation treatment was introduced alternatively after braiding. The RC sutures under different oxidation time were characterized by ATR-FTIR, electrical conductivity, XRD analysis, physical properties and in vitro degradation property. We further demonstrate that the RC sutures were oxidized and formed the carboxylic (-COOH) functional group. With the extension of oxidation duration, the carboxyl content in TORC sutures increased gradually from 5.1 to 10.4% and the strength, weight, and diameter of TORC sutures decreased gradually. Moreover, we proved that the knot-pull strength of TORC-45 declined by 77.8% after 28 days, thus this sutures fulfilled U.S. Pharmacopeia requirement of knot-pull strength. We have shown that TEMPO oxidation reaction significantly promoted the degradation of TORC sutures. Overall, TORC sutures were successfully produced with favorable biodegradability, revealing potential prospects of clinical applications.

Green Synthesis of Fluorescent Carbon Dots from Gynostemma for Bioimaging and Antioxidant in Zebrafish.

Fluorescent carbon dots (CDs) have been synthesized via the calcination method using natural gynostemma as the precursor, without any toxic ingredients or surface passivation chemicals. CDs have a narrow size distribution, and the mean particle size is about 2.5 nm. CDs exhibit good water dispersibility and can emit intense blue fluorescence under 365 nm UV light in an aqueous solution, which can be stable in different conditions. The biotoxicity of CDs on the embryonic development of zebrafish is evaluated, the hatch rate and survival rate of embryos are around 90%, and the malformation rate is less than 10%. Because of the excellent fluorescence stability and biocompatibility, CDs can be used in zebrafish for bioimaging. In addition, the antioxidative stress property of CDs is investigated both in vitro and in vivo, and the presence of CDs can promote the mRNA expression of related genes to encode more antioxidant proteins in zebrafish. Therefore, fluorescent CDs would be a potential candidate for bioimaging and treating diseases caused by excessive oxidation damage, such as cancer, senility, and other diseases associated with aging.

Biodegradable N, O-carboxymethyl chitosan/oxidized regenerated cellulose composite gauze as a barrier for preventing postoperative adhesion.

Tissue adhesion is one of the most common complications after surgery (especially after abdominal surgery), causing notable influences after the damaged tissue has healed. A physical barrier placed between the wound site and the adjacent tissues is a convenient and highly effective technique to minimize or prevent abdominal adhesions. In this work, the N, O-carboxymethyl chitosan/oxidized regenerated cellulose (N, O-CS/ORC) composite gauze was prepared. The N, O-CS/ORC composite gauze is degradable; in addition, the gauze exhibits excellent antimicrobial functionality against S. aureus and E. coli bacteria. Moreover, the notable hemostatic efficacy of the N, O-CS/ORC composite gauze was confirmed in rabbit livers/ears as models. The results showed that the N, O-CS/ORC composite gauze is nontoxic toward normal cells and can restrain the adhesion of fibroblast cells, thereby indicating its potential use in preventing tissue adhesion. In addition, the rat models for abdominal defect-cecum abrasion were used to evaluate the efficacy of N, O-CS/ORC composite gauze in preventing tissue adhesions after surgery. The results indicated that the N, O-CS/ORC composite gauze can significantly prevent postsurgical peritoneal adhesions. Finally, the potential anti-adhesion mechanism of the N, O-CS/ORC composite gauze, which may attribute to the combination of barrier function and instinct activity of N, O-CS and ORC, was investigated.

Acid-sensitive polymeric vector targeting to hepatocarcinoma cells via glycyrrhetinic acid receptor-mediated endocytosis.

Liver cancer is one of the top death causing cancers, traditional treatments have not settled for the requirement of patients. In this work, a smart acid-responsive micelle based on glycyrrhetinic acid modified chitosan-polyethyleneimine-4-Hydrazinobenzoic acid-doxorubicin (GA-CS-PEI-HBA-DOX) was synthesized for targeted delivery of DOX to liver cancer. A dual pH-sensitive and receptor-mediated strategy has been exploited to enhance the delivery efficiency. The micelle possesses positive charges under pH 6.8 and can be turned into negative charges above pH 7.0, which help to be accumulated in tumor tissues (pH 6.0-7.0). In the intracellular environment (pH 4.5-6.5) of tumor cells, the pH-sensitive hydrazone bonds between DOX and GA-CS-PEI-HBA would break and release as much as 90.3% of the encapsulated payloads in 48 h. In addition, GA was modified to improve the targeting abilities. The micelles exhibited high lethality to HepG2 cells while showed much lower cytotoxicity to HUVEC cells. With high drug-loading capacity and the targeted release ability, the GA-CS-PEI-HBA-DOX micelle might be employed as a promising candidate for targeted cancer treatment.

Carbon nanotube-modified oxidized regenerated cellulose gauzes for hemostatic applications.

Functionalized carbon nanotubes have recently received interest because of their unique properties, especially in the biomedical field. In this research, unmodified multiwalled carbon nanotubes (MWCNTs), and functionalized carbon nanotubes with amino groups (MWCNTs-NH2) and carboxyl groups (MWCNTs-COOH) were grafted to oxidized regenerated cellulose (ORC) gauze to fabricate novel functionalized ORC, and the performance of the functionalized gauze was investigated. The functionalized ORC was characterized by FT-IR, XPS and SEM, which showed the different kinds of CNTs grafted on its surface. The XPS results demonstrated the successful incorporation of functionalized MWCNTs in the active layer of modified ORC gauze. Meanwhile, the specific surface area of the CNTs modified functionalized ORC gauze was improved in varying degrees, whereas the porosity was slightly decreased. Furthermore, hydrophilicity experiment results presented a significant increment in water uptake of the functionalized CNTs grafted to the surface of the ORC gauze. Results of the hemostatic performance test on rabbit ear artery and liver showed that compared with the original ORC gauze, the bleeding time was significantly reduced when using the functionalized CNTs modified ORC hemostatic gauze. Moreover, the results also showed that the MWCNTs-COOH/ORC functionalized gauze had outstanding hemostatic efficiency.

pH-Sensitive mesoporous silica nanoparticles for chemo-photodynamic combination therapy.

In order to optimize the chemotherapeutic efficacy of doxorubicin (DOX) and improve the photodynamic therapeutic effectiveness of rose bengal (RB), a mesoporous silica nanoparticle system was designed as the carrier of RB and DOX for chemo-photodynamic combination therapy. A pH-sensitive strategy has been exploited to enhance the delivery efficiency. Our results suggested that the production of singlet oxygen was independent of the release of RB while strongly influenced by the external DOX layer. This method showed several benefits, including accelerating cellular uptake of the payloads and enabling chemo-photodynamic combination therapy for synergistic cancer treatment. Our study provides a new way for co-delivery of chemotherapy agents and photosensitizers.

Biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers for rapid hemostasis.

Efficient and biodegradable hemostatic materials become increasingly important in civilian and military clinical. However, traditional hemostatic materials are difficult to achieve expected effects especially in parenchymal organs with rich vascularity. In facing these challenges, we designed a biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers (CPNFs-Col sponge) for rapid hemostasis. With specific performances, such as rapid water absorption ability, the positive surface rich in amino groups and high specific surface area (952.5m2g-1), the obtained CNPFs-Col sponge with optimized composition could activate the intrinsic pathway of coagulation cascade, induce haemocytes and platelets adherence, promote the blood clotting and achieve hemorrhage control in vitro and in vivo. In addition, the CNPFs-Col sponge can be completely biodegraded in 3 weeks, which is suitable for post-operative treatment and peritoneal adhesion prevention. It can be concluded that the CPNFs-Col sponge would become a promising candidate for clinical hemostatic applications.

A novel mutation of KRT9 gene in a Chinese Han pedigree with epidermolytic palmoplantar keratoderma.

BACKGROUND: Mutations of keratin 9 (KRT9) gene is a hot research area of epidermolytic palmoplantar keratoderma (EPPK). AIMS: To identify the genes caused the EPPK of a Chinese family. PATIENTS/METHODS: Three cases of lesions were collected for pathological examination. Genomic DNA was extracted from peripheral blood samples of six patients and five healthy individuals and 100 unrelated individuals. Polymerase chain reaction (PCR) was used to amplify exons 1 of KRT9 gene. PCR products were sequenced to identify potential mutations. RESULTS: The lesion pathology of the proband and two ill relatives diagnosed EPPK. A new heterozygous missense mutation (488G>T) was identified in the 488 site of exon 1 of KRT9 gene in all six patients, which resulted in substitution of thymine for guanine, and substitution of leucine acid for arginine acid at position 163 of the KRT9 protein. The same mutation was not found in the five healthy individuals of the family and 100 unrelated individuals. CONCLUSIONS: The new heterozygous missense mutation (488G>T) of KRT9 gene is probably the cause of EPPK in this Chinese family.

[The correlation of the fetal cytokeratin expressing in epidermal cells and the different outcomes of wound repairing].

OBJECTIVE: To investigate the changing regular of specific cytokeratin (CK) markers expressing in human pseudoepitheliomatous hyperplasia (PEH), keloids (Ke) and hypertrophic scar (HS) lesion, and to explore the correlation between such changes and the different outcomes of wound repair. METHODS: Histopathology and immunohistochemistry (IHC) double staining methods were used in samples of human PEH, Ke, HS and NS to determine the distribution characteristics and changing regularity of CKs in epidermal tissues. RESULTS: No CK8&18 and CK17 expressed in epidermis of NS group, while CK8&18(+) cells and CK17(+) cells were detected in epidermis of active-stage Ke, HS and PEH. The quantities of CK8&18(+) cells and CK17(+) cells ranked as follows: PEH > Ke > HS and HS > Ke > PEH (P < 0.05). CK19(+) cells and CK5&6(+) cells expressed similar changing trend, while reverse trend of CK10(+) cells was detected in epidermal cells, with local epidermal hyperplasia, cells morphological changes and sub-epidermal inflammatory reaction. CONCLUSION: Different degree of de-differentiation and terminal differentiation imbalance are found in epidermal cells of active-stage PEH, Ke and HS, which hint the correlation between the abnormal proliferation and differentiation of epidermal cells and the different outcomes of wound repair.