Dual Functional Lysozyme-Chitosan Conjugate for Tunable Degradation and Antibacterial Activity.
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ABSTRACT:
SUBMITTER: Kim S
PROVIDER: S-EPMC7494203 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The recent emergence of antibiotic-resistant bacteria requires the development of new antibiotics or new agents capable of enhancing antibiotic activity. This study evaluated the antibacterial activity of lysozyme-chitosan oligosaccharide conjugates (LYZOX) against Pseudomonas aeruginosa, Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus (MRSA), which should resolve the problem of antibiotic-resistant bacteria. Bactericidal tests showed that LYZOX killed 50% more P. aeruginosa (NBRC 13275), A. baumannii and MRSA than the control treatment after 60 min. In addition, LYZOX was shown to inhibit the growth of P. aeruginosa (NBRC 13275 and PAO1), A. baumannii and MRSA better than its components. To elucidate the antibacterial mechanism of LYZOX, we performed cell membrane integrity assays, N-phenyl-1-naphthylamine assays, 2-nitrophenyl β-D-galactopyranoside assays and confocal laser scanning microscopy. These results showed that LYZOX affected bacterial cell walls and increased the permeability of the outer membrane and the plasma membrane. Furthermore, each type of bacteria treated with LYZOX was observed by electron microscopy. Electron micrographs revealed that these bacteria had the morphological features of both lysozyme-treated and chitosan oligosaccharide-treated bacteria and that LYZOX destroyed bacterial cell walls, which caused the release of intracellular contents from cells. An acquired drug resistance test revealed that these bacteria were not able to acquire resistance to LYZOX. The hemolytic toxicity test demonstrated the low hemolytic activity of LYZOX. In conclusion, LYZOX exhibited antibacterial activity and low drug resistance in the presence of P. aeruginosa, A. baumannii and MRSA and showed low hemolytic toxicity. LYZOX affected bacterial membranes, leading to membrane disruption and the release of intracellular contents and consequent bacterial cell death. LYZOX may serve as a novel candidate drug that could be used for the control of refractory infections.
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Project description:Tuning hydrogel degradation enables effective and successful tissue regeneration by modulating cellular behaviors and matrix formation. In this work, we develop a novel degradable hydrogel scaffold on the basis of a unique enzyme-substrate complex by photocrosslinking. Chitosan and lysozyme are chemically modified with methacrylate moieties to be tethered in hydrogels, and in the presence of riboflavin initiator, these hydrogels are cured by blue light irradiation. The incorporation of lysozyme to chitosan hydrogels accelerates the degradation rate of the crosslinked hydrogels in a dose-dependent manner, as evidenced by an increase in pore size and interconnectivity through cryogenic scanning electron microscopy over time. Those noncytotoxic materials significantly enhance cellular proliferation and migration, which contribute to osteogenic differentiation of encapsulated mesenchymal stem cells in vitro and bone formation in mouse calvarial defects. These findings suggest a promising strategy to modulate the degradation behavior of hydrogels for use in tissue engineering.
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Project description:BackgroundClinic treatment of diabetic foot ulcers (DFUs) is considerably challenging. Impaired wound healing may be caused by poor vascularization and dysfunction of the extracellular matrix, which leads to poor re-epithelialization and increased risk of infection. In this study, we evaluated the treatment potential of a functional dressing comprising quaternized chitosan (hydroxypropyltrimethyl ammonium chloride chitosan) and magnesium (Mg) on DFUs.MethodsDressings were prepared by vacuum freeze-drying. The cellular proliferation, migration, and angiogenesis potential of the functional dressings were determined in vitro. Methicillin-resistant Staphylococcus aureus (MRSA, ATCC43300) and methicillin-resistant Staphylococcus epidermidis 287 (MRSE287) were used to evaluate the antibacterial efficiency of the dressings. Finally, a diabetic rat model with infected wounds was used to further evaluate the effects of functional dressings on the healing of DFUs.ResultsFunctional dressings facilitated the migration of human dermal fibroblasts and human umbilical vein endothelial cells (HUVECs), while also stimulating angiogenesis in HUVECs. Additionally, the functional dressing could effectively eradicate MRSA and MRSE, exhibiting excellent antibacterial ability against drug-resistant bacteria. The results of in vivo microbiological and histological tests demonstrated effective anti-infection ability and wound-healing potential of this functional dressing.ConclusionsThe dual-functional dressing exhibited wound-healing ability and anti-infection efficiency, demonstrating potential application prospects in DFU treatment.Translational potential of this articleAs one of the common and serious complications of diabetes, DFUs do not heal easily, causing great suffering to patients. Therefore, improvement in the prognosis of DFUs is a crucial clinical need. The dual-functional dressing prepared in this study was proven to improve the treatment of DFUs, both in vitro and in vivo. Considering its urgent clinical necessity and good biocompatibility of its raw materials, such as alginate, Mg, and chitosan derivatives, this dual-functional dressing presents good prospects for clinical translation.
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Project description:This study proposes to develop a dual-acting antibacterial film of porous chitosan (Cs) embedded with small molecular compound, which possesses photosensitive characteristics with bactericidal efficacy, to promote the accelerated recovery of infectious wounds. The Cs/small molecular compound (Cs-cpd.2) dressing was prepared using the freeze-drying method. Characterization of the synthesized Cs-cpd.2 indicated that it has high porosity and moisture absorption effect, hence enhancing the absorption of wound exudate. Experimental results showed that Cs-cpd.2 dressing has good bactericidal and bacteriostatic effects on Staphylococcus aureus under visible-light irradiation and has antibacterial effect in the dark. It was also found that the small molecular compound does not have cytotoxicity at a dose of 0-5 μM. Furthermore, Cs-cpd.2 that contained small molecular compound with a concentration of 0.3-1 μM has positive effect on both the cell viability rate and cell proliferation rate of human fibroblast CG1639. Cs-cpd.2 can significantly promote cell proliferation when the small molecular compound and the basic fibroblast growth factor bFGF were added together. Therefore, the proposed Cs-cpd.2 dressing is feasible for photodynamic therapy (PDT) and clinical wound dressing applications.
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Project description:The antibacterial activity of N,O-acylated chitosan derivative with linoleic acid (CH_LA) was tested by disc and well diffusion, agar impregnation and microdilution methods against Staphylococcus aureus, Escherichia coli and Helicobacter pylori strains. Hydrophobically modified chitosan (HMC) was expected to exhibit enhanced antibacterial activity and specific mucin interactions. Although diffusion tests have not indicated the antibacterial potential of chitosan (CH) or CH_LA, the results of the microdilution method demonstrated that tested polymers significantly reduced the amount of living bacteria cells in different concentrations depending on the microorganism. Additionally, CH_LA was characterized by enhanced antibacterial activity compared to CH, which may suggest a different mechanism of interaction with S. aureus and H. pylori. Furthermore, the UV-VIS analysis revealed that the amphiphilic character of derivative led to strong CH_LA-mucin interactions. The study proved the high potential of CH_LA in antibacterial applications, especially for the gastrointestinal tract.
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Project description:The synthesis of multifunctional photothermal nanoagents for antibiotic loading and release remains a challenging task in nanomedicine. Herein, we investigated a simple, low-cost strategy for the preparation of CuS-BSA nanoparticles (NPs) loaded with a natural enzyme, lysozyme, as an antibacterial drug model under physiological conditions. The successful development of CuS-BSA NPs was confirmed by various characterization tools such as transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Lysozyme loading onto CuS-BSA NPs was evaluated by UV/vis absorption spectroscopy, Fourier-transform infrared spectroscopy (FTIR), zeta potential, and dynamic light scattering measurements. The CuS-BSA/lysozyme nanocomposite was investigated as an effective means for bacterial elimination of B. subtilis (Gram-positive) and E. coli (Gram-negative), owing to the combined photothermal heating performance of CuS-BSA and lysozyme release under 980 nm (0.7 W cm-2) illumination, which enhances the antibiotic action of the enzyme. Besides the photothermal properties, CuS-BSA/lysozyme nanocomposite possesses photodynamic activity induced by NIR illumination, which further improves its bacterial killing efficiency. The biocompatibility of CuS-BSA and CuS-BSA/Lysozyme was elicited in vitro on HeLa and U-87 MG cancer cell lines, and immortalized human hepatocyte (IHH) cell line. Considering these advantages, CuS-BSA NPs can be used as a suitable drug carrier and hold promise to overcome the limitations of traditional antibiotic therapy.
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Project description:Bacteriophages and bacteriophage-derived peptidoglycan hydrolases (endolysins) present promising alternatives for the treatment of infections caused by multidrug resistant Gram-negative and Gram-positive pathogens. In this study, Gp105, a putative lysozyme murein hydrolase from Enterobacter phage myPSH1140 was characterized in silico, in vitro as well as in vivo using the purified protein. Gp105 contains a T4-type lysozyme-like domain (IPR001165) and belongs to Glycoside hydrolase family 24 (IPR002196). The putative endolysin indeed had strong antibacterial activity against Gram-negative pathogens, including E. cloacae, K. pneumoniae, P. aeruginosa, S. marcescens, Citrobacter sp., and A. baumannii. Also, an in vitro peptidoglycan hydrolysis assay showed strong activity against purified peptidoglycans. This study demonstrates the potential of Gp105 to be used as an antibacterial protein to combat Gram-negative pathogens.
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Project description:Lysozyme, an antibacterial enzyme, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles adopting various strategies. The synthesized particles were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), and TEM to observe their morphology and surface chemistry. The silver nanoparticles were evaluated for their antimicrobial activity against several bacterial species and various bacterial strains within the same species. The cationic silver nanoparticles were found to be more effective against Pseudomonas aeruginosa 3 compared to other bacterial species/strains investigated. Some of the bacterial strains of the same species showed variable antibacterial activity. The difference in antimicrobial activity of these particles has led to the conclusion that antimicrobial products formed from silver nanoparticles may not be equally effective against all the bacteria. This difference in the antibacterial activity of silver nanoparticles for different bacterial strains from the same species may be due to the genome islands that are acquired through horizontal gene transfer (HGT). These genome islands are expected to possess some genes that may encode enzymes to resist the antimicrobial activity of silver nanoparticles. These silver nanoparticles may thus also be used to differentiate some bacterial strains within the same species due to variable silver resistance of these variants, which may not possible by simple biochemical tests.
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