Preparing natural biocomposites of N-quaternary chitosan with antibacterial activity to reduce consumption of antibacterial drugs

Electrospun O-quaternary ammonium chitosan/polyvinyl alcohol nanofibrous film by application of Box-Behnken design response surface method for eliminating pathogenic bacteria

In this study, O-quaternary ammonium chitosan (O-HTCC) containing bicationic antibacterial active groups was synthesized to develop an O-HTCC/PVA porous nanofibrous film to enhance antibacterial activity, leveraging surface modification and nano-porous structure design. Uniform and smooth nanofibrous structures (average diameter: 72-294 nm) were successfully obtained using a simple and feasible electrospinning method. A response surface model via Box-Behnken design (BBD) was used to clarify the interaction relationship between O-HTCC fiber diameter and three critical electrospinning parameters (O-HTCC concentration, applied voltage, feed flow rate), predicting that the minimum O-HTCC fiber diameter (174 nm) could be achieved with 7 wt% of O-HTCC concentration, 14 kV of voltage, and 0.11 mL/h of feed flow rate. Linear regression (R2 = 0.9736, Radj2 = 0.9716) and the Anderson Darling test demonstrated the excellent fit of the RSM-BBD model. Compared to N-HTCC/PVA nanofibrous film, the O-HTCC/PVA version showed increased growth inhibition and more effective antibacterial efficacies against Escherichia coli (E. coli) (~;86.34 %) and Staphylococcus aureus (S. aureus) (~;99.99 %). DSC revealed improved thermal stability with an increased melting temperature (238 °C) and endothermic enthalpy (157.7 J/g). This study holds potential for further development of antibacterial packaging to extend food shelf-life to reduce bacterial infection.

Chitosan-gentamicin conjugate attenuates heat stress-induced intestinal barrier injury via the TLR4/STAT6/MYLK signaling pathway: In vitro and in vivo studies

Heat stress (HS) has a negative impact on animal health. A modified chitosan-gentamicin conjugate (CS-GT) was prepared to investigate its potential protective effects and mechanism of action on heat stress-induced intestinal mucosa injury in IPEC-J2 cells and mouse 3D intestinal organs in a mouse model. CS-GT significantly (P < 0.01) reversed the decline in transmembrane resistance and increased the FITC-dextran permeability of the IPEC-J2 monolayer fusion epithelium caused by heat stress. Heat stress decreased the expression of the tight binding proteins occludin, claudin1, and claudin2. However, pretreatment with CS-GT significantly increased (P < 0.01) the expression of these tight binding proteins. Mechanistically, CS-GT inhibited the activation of the TLR4/STAT6/MYLK signaling pathway induced by heat stress. Molecular docking showed that CS-GT can bind effectively with TLR4. In conclusion, CS-GT alleviates heat stress-induced intestinal mucosal damage both in vitro and in vivo. This effect is mediated, at least partly, by the inhibition of the TLR4/STAT6/MYLK signaling pathway and upregulation of tight junction proteins. These findings suggest that CS-GT may have therapeutic potential in the prevention and treatment of heat stress-related intestinal injury.

Corrigendum: Applications of chitosan and its derivatives in skin and soft tissue diseases

[This corrects the article DOI: 10.3389/fbioe.2022.894667.].

Implantable Sandwich-like Scaffold/Fiber Composite Spatiotemporally Releasing Combretastatin A4 and Doxorubicin for Efficient Inhibition of Postoperative Tumor Recurrence

Tumor recurrence is a critical conundrum in the postoperative therapy, on account of severe bleeding with disseminated tumor cells, residual tumor cells, and the rich nutrient and oxygen supply transported to tumors by the abundant blood vessels. Biodegradable drug-loaded implants, inserted in the resection cavity right away upon the surgery, possess bleeding prevention and efficient chemotherapeutic capabilities, considered to be a promising strategy to efficiently inhibit the recurrence of the solid tumor. Here, we developed a sandwich-like composite consisting of the combretastatin A4 (CA4)-loaded 3D-printed scaffold and doxorubicin (DOX)-loaded electrospun fiber (Scaffold-CA4@Fiber-DOX), presenting hemostatic, chemotherapeutic, and antibacterial potencies. The lyophilized 3D-printed scaffold with a porous structure rapidly absorbed and clotted the blood cells and disseminated tumor cells to prevent bleeding and tumor metastasis. Subsequently, the preferentially released CA4 from the scaffold disrupted the microtubules of the vascular endothelial cell, resulting in vascular deformation and consequent insufficient nutrient supply to the solid tumor. The sustained release of DOX from the sandwiched electrospun fiber dramatically inhibited the peripheral tumor cell proliferation. This all-in-one multifunctional implant system, combining efficient vascular disruption and chemotherapy, provides a promising strategy for postoperative tumor therapy.

Applications of Chitosan and its Derivatives in Skin and Soft Tissue Diseases

Chitosan and its derivatives are bioactive molecules that have recently been used in various fields, especially in the medical field. The antibacterial, antitumor, and immunomodulatory properties of chitosan have been extensively studied. Chitosan can be used as a drug-delivery carrier in the form of hydrogels, sponges, microspheres, nanoparticles, and thin films to treat diseases, especially those of the skin and soft tissue such as injuries and lesions of the skin, muscles, blood vessels, and nerves. Chitosan can prevent and also treat soft tissue diseases by exerting diverse biological effects such as antibacterial, antitumor, antioxidant, and tissue regeneration effects. Owing to its antitumor properties, chitosan can be used as a targeted therapy to treat soft tissue tumors. Moreover, owing to its antibacterial and antioxidant properties, chitosan can be used in the prevention and treatment of soft tissue infections. Chitosan can stop the bleeding of open wounds by promoting platelet agglutination. It can also promote the regeneration of soft tissues such as the skin, muscles, and nerves. Drug-delivery carriers containing chitosan can be used as wound dressings to promote wound healing. This review summarizes the structure and biological characteristics of chitosan and its derivatives. The recent breakthroughs and future trends of chitosan and its derivatives in therapeutic effects and drug delivery functions including anti-infection, promotion of wound healing, tissue regeneration and anticancer on soft tissue diseases are elaborated.

Therapeutic effect and immune mechanism of chitosan-gentamicin conjugate on Pacific white shrimp (Litopenaeus vannamei) infected with Vibrio parahaemolyticus

To explore the disease resistance mechanism of chitosan conjugates, chitosan-gentamicin conjugate (CS-GT) was synthesized and systematically characterized, the immune mechanism of CS-GT on Litopenaeus vannamei infected with Vibrio parahaemolyticus was further explored. The results showed that imine groups in CS-GT were effectively reduced. Dietary supplementation of CS-GT can significantly increase the survival rate, total hemocyte counts, the antioxidant and immune related enzyme activity levels of shrimps (P < 0.05), which are all dose-dependent under the experimental conditions. In addition, CS-GT can protect the hepatopancreas from invading bacteria and alleviate inflammation. Particularly, CS-GT promotes the expressions of legumain (LGMN), lysosomal acid lipase (LIPA) and Niemann-Pick type C2 (NPC2) up-regulated. It is speculated that CS-GT may stimulate the lysosome to phagocytose pathogens more effectively. In conclusions, shrimps fed with CS-GT can produce immune response via lysosome and greatly improve the disease resistance to Vibrio parahaemolyticus.

Preparation of Cross-linked Chitosan Quaternary Ammonium Salt Hydrogel Films Loading Drug of Gentamicin Sulfate for Antibacterial Wound Dressing

Hydrogels, possessing high biocompatibility and adaptability to biological tissue, show great usability in medical applications. In this research, a series of novel cross-linked chitosan quaternary ammonium salt loading with gentamicin sulfate (CTMCSG) hydrogel films with different cross-linking degrees were successfully obtained by the reaction of chitosan quaternary ammonium salt (TMCS) and epichlorohydrin. Fourier transform infrared spectroscopy (FTIR), thermal analysis, and scanning electron microscope (SEM) were used to characterize the chemical structure and surface morphology of CTMCSG hydrogel films. The physicochemical property, gentamicin sulphate release behavior, cytotoxicity, and antibacterial activity of the CTMCSG against Escherichia coli and Staphylococcus aureus were determined. Experimental results demonstrated that CTMCSG hydrogel films exhibited good water stability, thermal stability, drug release capacity, as well as antibacterial property. The inhibition zone of CTMCSG hydrogel films against Escherichia coli and Staphylococcus aureus could be up to about 30 mm. Specifically, the increases in maximum decomposition temperature, mechanical property, water content, swelling degree, and a reduction in water vapor permeability of the hydrogel films were observed as the amount of the cross-linking agent increased. The results indicated that the CTMCSG-4 hydrogel film with an interesting physicochemical property, admirable antibacterial activity, and slight cytotoxicity showed the potential value as excellent antibacterial wound dressing.

Low molecular weight chitosan-cyanocobalamin nanoparticles for controlled delivery of ciprofloxacin: Preparation and evaluation

This study was carried out to project a safe nano-drug carrier composed of chitosan and cyanocobalamin (CNCbl) to improve oral delivery of ciprofloxacin hydrochloride (CIP). CIP is classified in class IV of the biopharmaceutical classification system with low solubility and permeabilityA, so it has some problems if given orally. Novel conjugate of low molecular weight chitosan, as a natural biopolymer, and CNCbl was synthesized, and then drug loading and in-vitro drug release were assessed. The loading of CIP was optimized by the Design-Expert software and the central composite design method, and that the optimal drug loading efficiency (57%) was obtained via analysis of variance (ANOVA). In-vitro drug release studies showed controlled release patterns in two various conditions, namely phosphate buffer saline (pH = 7.4) and 0.1 N HCl. Functionalized nano-drug-loaded carrier showed cytotoxicity as much as that of free drug, particle size less than 100 nm as well as positive zeta potential. Due to the beneficial properties of the chitosan-based drug carrier and the suitable features of the CIP-loaded carrier, this chitosan-based nano-drug delivery system can be regarded as an ideal candidate for oral delivery of the CIP as a drug model.

Effects of Chitosan-Gentamicin Conjugate Supplement on Non-Specific Immunity, Aquaculture Water, Intestinal Histology and Microbiota of Pacific White Shrimp (Litopenaeus vannamei)

When the aquaculture water environment deteriorates or the temperature rises, shrimp are susceptible to viral or bacterial infections, causing a large number of deaths. This study comprehensively evaluated the effects of the oral administration of a chitosan-gentamicin conjugate (CS-GT) after Litopenaeus vannamei were infected with Vibrio parahaemolyticus, through nonspecific immunity parameter detection, intestinal morphology observation, and the assessment of microbial flora diversification by 16S rRNA gene sequencing. The results showed that the oral administration of CS-GT significantly increased total hemocyte counts and reduced hemocyte apoptosis in shrimp (p < 0.05). The parameters (including superoxide dismutase, glutathione peroxidase, glutathione, lysozyme, acid phosphatase, alkaline phosphatase, and phenoloxidase) were significantly increased (p < 0.05). The integrity of the intestinal epithelial cells and basement membrane were enhanced, which correspondingly alleviated intestinal injury. In terms of the microbiome, the abundances of Vibrio (Gram-negative bacteria and food-borne pathogens) in the water and gut were significantly reduced. The canonical correspondence analysis (CCA) showed that the abundances of Vibrio both in the water and gut were negatively correlated with CS-GT dosage. In conclusion, the oral administration of CS-GT can improve the immunity of shrimp against pathogenic bacteria and significantly reduce the relative abundances of Vibrio in aquaculture water and the gut of Litopenaeus vannamei.

Environmentally responsive and anti-bugs textile finishes - Recent trends, challenges, and future perspectives

Bugs, such as microorganisms and insects, are present in the environment and sometimes can be health-hazardous if the living environment is not maintained following proper hygienic regulations. In the present scenario of increasing public awareness, environmental consciousness, and growing demand for easy-care, and disinfected textiles, the manufacturing of protective and easy-to-care textiles has become a key necessity of the modern world. Comfortable, clean, hygienic, antimicrobial, and insect repelling properties of textile goods are gaining the accelerating research momentum as a basic requirement to produce multifunctional textiles. These functional finishes have numerous applications such as in-home textiles, bed nets, and tenting, camping gear as well as in military uniforms. Synthetic antimicrobial and insect repellents are quite effective against insects and microscopic organisms but are slightly toxic to the human being and the environment. To overcome these problems, researchers are considering natural agents for functional finishes, but their effectiveness is less durable to textile material. Besides needful advantages, the excessive use of dyes in finishing processes heavily required washing cycles and ultimately release various types of hazardous dyes or wasteful effluents in the environment. This review reports the chemical composition and recent developments in textile finishes, particularly antimicrobial and insect repellent textile finishes. A large number of commonly used antimicrobial agents (i.e. chitosan, zwitterionic compounds, silver and silver-based compounds, titanium dioxide nanoparticles, imidazolium salts, triclosan and quaternary ammonium salts) and insect repellent textile finishes (i.e. N‑N‑diethyl‑m‑toluamide, permethrin, cypermethrin, pyrethrum, picaridin, bioallethrin, citriodiol and essential oils) have been presented. Finally, the review is wrapped up with major research gaps/challenges, concluding remarks, and future opportunities in this area of research.