<p>Preparation And Antibacterial Effects Of Carboxymethyl Chitosan-Modified Photo-Responsive <em>Camellia</em> Sapogenin Derivative Cationic Liposomes</p>

Abstract

BackgroundBacterial resistance to antibiotics is a persistent and intractable problem. The sapogenin isolated from the seeds of Camellia oleifera can inhibit antibiotic-resistant bacteria after structural modification.PurposeThis study aims to improve sapogenin's antibacterial activity and avoid bacterial resistance based on nano-preparation with photo responsiveness.MethodsThe liposome shell material of carboxymethyl chitosan-phosphatidyl ethanolamine (CMC-PE) was prepared using amidation reaction, and photo-responsive cationic (PCC) liposomes containing Camellia sapogenin derivative (CSD) and photosensitizer pheophorbide-a were prepared by film dispersion method. Encapsulation efficiency, drug loading, zeta potential, particle size distribution, morphology and stability of the PCC liposomes were determined by HPLC, particle size analyzer, transmission electron microscopy (TEM) and fluorescence microscopy. Photo-responsive release of CSD in the PCC liposomes was determined by laser (0.5 mW/cm2) at 665 nm. Antibacterial activity of the PCC liposomes with or without irradiation was analyzed by MIC50, MBC, MBIC50, and bacterial morphology to evaluate the antibacterial effects on amoxicillin resistant Escherichia coli and Staphylococcus aureus.ResultsSize distribution, zeta potential, encapsulation efficiency and drug loading of the PCC liposomes were 189.23 ± 2.12 nm, 18.80 ± 1.57 mV, 83.52 ± 1.53% and 2.83 ± 0.05%, respectively. The PCC liposomes had higher storage stability and gastrointestinal stability, and no obvious hemolytic toxicity to rabbit red blood cells and no cytotoxicity after incubation with Hela cells. The photosensitizer pheophorbide-a was uniformly dispersed in the phospholipid layer of the PCC liposomes and increased the CSD release after irradiation. The PCC liposomes could bind to bacteria and impaired their morphology and structure, and had significant bactericidal effect on amoxicillin resistant E. coli and S. aureus.ConclusionThe photo-responsive PCC liposomes are efficient antibacterial agents for avoidance of bacterial resistance against antibiotics.

Identification of Plant Soot as Novel Safe Feed Additive: Evaluation of 90-Day Oral Toxicity and Prenatal Developmental Toxicity in Rats

“…It has been known that overused antibiotics in animal feed could lead to the development of drug-resistant bacteria and drug residues as threats to human health, so they have been phased out as growth promoters in many countries (12)(13)(14). On the other hand, there is increasing value in finding natural and harmless feed additives to strengthen the immune system and fight against various diseases, thus new antibiotic substitution strategies and alternative feed additives such as microecological preparations and traditional herbal medicine are currently increasing in popularity (15)(16)(17). It reported that the dietary supplementation with propionibacteria promoted mucus secretion characterized by rising goblet cells counts, neutral mucin production, and the longer villus-crypt units.…”

Oleic Acid Copolymer as A Novel Upconversion Nanomaterial to Make Doxorubicin-Loaded Nanomicelles with Dual Responsiveness to pH and NIR

“…The cytotoxicity of mPEG-PEI-(NBS, OA) nanomicelles was estimated by MTT viability assay against A549 cells [ 37 ]. Briefly, the A549 cells were seeded in a 96-well plate at a density of 1 × 10 4 cells per well and incubated in DMEM medium at 37 °C in the presence of 5% CO 2 for 24 h. After removing the culture medium, the cells were treated with 100 μL of fresh medium containing different concentrations of the nanomicelles (the corresponding concentration was 0.5, 1, 2, 4, 8, 16, 32, 64, 128, and 256 μg/mL) for 24 h. Subsequently, the medium containing the nanomicelles was removed, and the cells were washed three times with PBS solution.…”

Functional insights to the development of bioactive material for combating bacterial infections

“…In addition, because bacteria have difficulty surviving from physically destroyed cell structures, cationic liposomes can also destroy bacterial membranes and walls through electrostatic interactions, so cationic liposomes have specific antibacterial mechanisms and antibacterial activity, and this specific mechanism also effectively reduces the risk of enhanced bacterial resistance (Zhang et al, 2019). Cationic liposomes, such as those composed of dioctyl-dimethylammonium bromide (DODAB), are inherently inhibitory to both gram-Frontiers in Bioengineering and Biotechnology frontiersin.org negative and gram-positive bacteria, even without encapsulated antibiotics (Laune et al, 2022).…”