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In this study, chitosan and alginate were selected to prepare alginate/chitosan nanoparticles to load the drug lovastatin by the ionic gelation method. The synthesized nanoparticles loaded with drug were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), laser scattering and differential scanning calorimetry (DSC) methods. The FTIR spectrum of the alginate/chitosan/lovastatin nanoparticles showed that chitosan and alginate interacted with lovastatin through hydrogen bonding and dipolar-dipolar interactions between the C-O, C=O, and OH groups in lovastatin, the C-O, NH, and OH groups in chitosan and the C-O, C=O, and OH groups in alginate. The laser scattering results and SEM images indicated that the alginate/chitosan/lovastatin nanoparticles have a spherical shape with a particle size in the range of 50–80 nm. The DSC diagrams displayed that the melting temperature of the alginate/chitosan/lovastatin nanoparticles was higher than that of chitosan and lower than that of alginate. This result means that the alginate and chitosan interact together, so that the nanoparticles have a larger crystal degree when compared with alginate and chitosan individually. Investigations of the in vitro lovastatin release from the alginate/chitosan/lovastatin nanoparticles under different conditions, including different alginate/chitosan ratios, different solution pH values and different lovastatin contents, were carried out by ultraviolet-visible spectroscopy. The rate of drug release from the nanoparticles is proportional to the increase in the solution pH and inversely proportional to the content of the loaded lovastatin. The drug release process is divided into two stages: a rapid stage over the first 10 hr, then the release becomes gradual and stable. The Korsmeyer-Peppas model is most suitable for the lovastatin release process from the alginate/chitosan/lovastatin nanoparticles in the first stage, and then the drug release complies with other models depending on solution pH in the slow release stage. In addition, the toxicity of alginate/chitosan/lovastatin (abbreviated ACL) nanoparticles was sufficiently low in mice in the acute toxicity test. The LD 50 of the drug was higher than 5000 mg/kg, while in the subchronic toxicity test with treatments of 100 mg/kg and 300 mg/kg ACL nanoparticles, there were no abnormal signs, mortality, or toxicity in general to the function or structure of the crucial organs. The results show that the ACL nanoparticles are safe in mice and that these composite nanoparticles might be useful as a new drug carrier.

Burns and other skin injuries are growing concerns as well as challenges in an era of antimicrobial resistance. Novel treatment options to improve the prevention and eradication of infectious skin biofilm-producing pathogens, while enhancing wound healing, are urgently needed for the timely treatment of infection-prone injuries. Treatment of acute skin injuries requires tailoring of formulation to assure both proper skin retention and the appropriate release of incorporated antimicrobials. The challenge remains to formulate antimicrobials with low water solubility, which often requires carriers as the primary vehicle, followed by a secondary skin-friendly vehicle. We focused on widely used chlorhexidine formulated in the chitosan-infused nanocarriers, chitosomes, incorporated into chitosan hydrogel for improved treatment of skin injuries. To prove our hypothesis, lipid nanocarriers and chitosan-comprising nanocarriers (≈250 nm) with membrane-active antimicrobial chlorhexidine were optimized and incorporated into chitosan hydrogel. The biological and antibacterial effects of both vesicles and a vesicles-in-hydrogel system were evaluated. The chitosomes-in-chitosan hydrogel formulation demonstrated promising physical properties and were proven safe. Additionally, the chitosan-based systems, both chitosomes and chitosan hydrogel, showed an improved antimicrobial effect against S. aureus and S. epidermidis compared to the formulations without chitosan. The novel formulation could serve as a foundation for infection prevention and bacterial eradication in acute wounds.

Green synthesis is a newly emerging field of nanobiotechnology that offers economic and environmental advantages over traditional chemical and physical protocols. Nontoxic, eco-friendly, and biosafe materials are used to implement sustainable processes. The current work proposes a new biological-based strategy for the biosynthesis of chitosan nanoparticles (CNPs) using Pelargonium graveolens leaves extract. The bioconversion process of CNPs was maximized using the response surface methodology. The best combination of the tested parameters that maximized the biosynthesis process was the incubation of plant extract with 1.08% chitosan at 50.38 °C for 57.53 min., yielding 9.82 ± 3 mg CNPs/mL. Investigation of CNPs by SEM, TEM, EDXS, zeta potential, FTIR, XRD, TGA, and DSC proved the bioconversion process's success. Furthermore, the antifungal activity of the biosynthesized CNPs was screened against a severe isolate of the phytopathogenic Botrytis cinerea . CNPs exerted efficient activity against the fungal growth. On strawberry leaves, 25 mg CNPs/mL reduced the symptoms of gray mold severity down to 3%. The higher concentration of CNPs (50 mg/mL) was found to have a reverse effect on the infected area compared with those of lower concentrations (12.5 and 25 mg CNPs/mL). Therefore, additional work is encouraged to reduce the harmful side effects of elevated CNPs concentrations.

Nanocarriers with positive surface charges are known for their toxicity which has limited their clinical appli- cations. The mechanism underlying their toxicity, such as the induction of inflammatory response, remains largely unknown. In the present study we found that injection of cationic nanocarriers, including cationic liposomes, PEI, and chitosan, led to the rapid appearance of necrotic cells. Cell necrosis induced by cationic nanocarriers is dependent on their positive surface charges, but does not require RIP1 and Mlkl. Instead, intracellular Na^＋ overload was found to accompany the cell death. Depletion of Na^＋ in culture medium or pretreatment of cells with the Na^＋/K^＋- ATPase cation-binding site inhibitor ouabain, protected cells from cell necrosis. Moreover, treatment with cationic nanocarriers inhibited Na^＋/K^＋-ATPase activity both in vitro and in vivo. The computational simulation showed that cationic carriers could interact with cation-binding site of Na^＋/K^＋-ATPase. Mice pretreated with a small dose of ouabain showed improved survival after injection of a lethal dose of cationic nanocarriers. Further analyses suggest that cell necrosis induced by cationic nanocarriers and the resulting leakage of mitochondrial DNA could trigger severe inflammation in vivo, which is mediated by a pathway involving TLR9 and MyD88 signaling. Taken together, our results reveal a novel mechanism whereby cationic nanocarriers induce acute cell necrosis through the interaction with Na^＋/K^＋-ATPase, with the subsequent exposure of mitochondrial damage-associated molecular patterns as a key event that mediates the inflammatory responses. Our study has important implications for evaluating the biocompatibility of nanocarriers and designing better and safer ones for drug delivery.

The emergence of strains that are resistant to the most commonly used antibiotics represents a great concern for global public health. This challenges the effectiveness of clinical treatment regimens and demands the development of alternative antigonococcal agent. In this regard, chitosan nanoparticles (CNPs) are known to have antimicrobial activity against a wide range of pathogens. Thus, they have become a potential candidate for combatting this era of multi-drug resistance. This study aims to formulate CNPs, characterize their physicochemical properties, and examine their antimicrobial activity against gonococcus. The ionic gelation method was used to prepare CNPs of different concentrations. Characterization for their particle size (PZ), polydispersity index (PDI), and zeta potential (ZP) was performed. The anti-microbial activity of CNPs was investigated against 13 WHO reference strains, using the broth dilution method. Cytotoxicity of CNPs and their effect on bacterial adhesion to HeLa cells were investigated. The average PZ and ZP of the prepared NPs were increased when the concentration of chitosan was increased from 1 to 5 mg/mL and found to be in the range of 193 nm ± 1.9 to 530 nm ± 13.3, and 14 mV ± 0.5 to 20 mV ± 1, respectively. Transmission electron microscopes (TEM) images revealed spherical NPs, and the NPs had a low PDI value of ≤0.27. The formed CNPs produced antibacterial activity against all tested strains, including those resistant to multiple antibiotics, with a minimum inhibitory concentration (MIC ) of 0.16 to 0.31 mg/mL and a minimum bactericidal concentration (MBC) of 0.31 to 0.61 mg/mL. Of note, at all MIC and MBC, the CNPs had no significant cytotoxic effect on HeLa cells and reduced bacterial adhesion to these cells at MBC doses. The present work findings suggest the potential of the CNPs for the treatment of gonorrhoea.

The usage of nanocomposites in water treatment has risen, resulting in their leaking into the soil, which is a major environmental concern. Earthworm ( Allolobophora caliginosa ) is used as a bioindicator that can accumulate most pollutants, even if they are present in low concentrations. The present study aimed to use earthworms as biological indicator for chitosan–saponin–bentonite nanocomposite (CSB NCs) in the soil. Earthworms were exposed to CSB NCs (0, 0.025, 0.05, 0.1, and 0.15 mg/500 g soil) for 7 consecutive days. CSB NCs induced significant damage and instability of the lysosomal membranes in coelomocytes in a dose-dependent manner. The exposure to CSB NCs resulted in a notable change in earthworm biochemical levels. Light microscopy revealed histological damage in the body wall and intestine of earthworm exposed to CSB NC. In addition, scanning electron microscopy showed morphological alterations in the anterior, dorsal, and ventral parts of the earthworm as well as in the anal region because of exposure to CSB NC. The present study demonstrated that earthworms exposed to CSB NCs had a depletion in antioxidants and presented histological alterations especially in high doses of nanocomposite. Also, treated earthworms showed substantial alterations in the surface topography. Exposure to CSB NC caused physiological and histological alteration in earthworms. This study emphasizes the urgent need to evaluate the environmental safety of nanocomposites used in water treatment.

Background Glycol chitosan nanoparticles (CNPs) have emerged as an effective drug delivery system for cancer diagnosis and treatment. Although they have great biocompatibility owing to biodegradable chemical structure and low immunogenicity, sufficient information on in vivo toxicity to understand the potential risks depending on the repeated high-dose have not been adequately studied. Herein, we report the results of in vivo toxicity evaluation for CNPs focused on the number and dose of administration in healthy mice to provide a toxicological guideline for a better clinical application of CNPs. Results The CNPs were prepared by conjugating hydrophilic glycol chitosan with hydrophobic 5β-cholanic acid and the amphiphilic glycol chitosan-5β-cholanic acid formed self-assembled nanoparticles with its concentration-dependent homogeneous size distributions (265.36–288.3 nm) in aqueous condition. In cell cultured system, they showed significantly high cellular uptake in breast cancer cells (4T1) and cardiomyocytes (H9C2) than in fibroblasts (L929) and macrophages (Raw264.7) in a dose- and time-dependent manners, resulting in severe necrotic cell death in H9C2 at a clinically relevant highly concentrated condition. In particular, when the high-dose (90 mg/kg) of CNPs were intravenously injected into the healthy mice, considerable amount was non-specifically accumulated in major organs (liver, lung, spleen, kidney and heart) after 6 h of injection and sustainably retained for 72 h. Finally, repeated high-dose of CNPs (90 mg/kg, three times) induced severe cardiotoxicity accompanying inflammatory responses, tissue damages, fibrotic changes and organ dysfunction. Conclusions This study demonstrates that repeated high-dose CNPs induce severe cardiotoxicity in vivo. Through the series of toxicological assessments in the healthy mice, this study provides a toxicological guideline that may expedite the application of CNPs in the clinical settings.

Cancer gene therapy requires the design of non-viral vectors that carry genetic material and selectively deliver it with minimal toxicity. Non-viral vectors based on cationic natural polymers can form electrostatic complexes with negatively-charged polynucleotides such as microRNAs (miRNAs). Here we investigated the physicochemical/biophysical properties of chitosan–hsa-miRNA-145 (CS–miRNA) nanocomplexes and the biological responses of MCF-7 breast cancer cells cultured in vitro . Self-assembled CS–miRNA nanocomplexes were produced with a range of (+/−) charge ratios (from 0.6 to 8) using chitosans with various degrees of acetylation and molecular weight. The Z-average particle diameter of the complexes was <200 nm. The surface charge increased with increasing amount of chitosan. We observed that chitosan induces the base-stacking of miRNA in a concentration dependent manner. Surface plasmon resonance spectroscopy shows that complexes formed by low degree of acetylation chitosans are highly stable, regardless of the molecular weight. We found no evidence that these complexes were cytotoxic towards MCF-7 cells. Furthermore, CS–miRNA nanocomplexes with degree of acetylation 12% and 29% were biologically active, showing successful downregulation of target mRNA expression in MCF-7 cells. Our data, therefore, shows that CS–miRNA complexes offer a promising non-viral platform for breast cancer gene therapy.

The antimicrobial capability of chitosan from Tenebrio molitor as compared with chitosan from crustacean ( Penaeus monodon ) on different pathogenic microorganisms of concern in food safety was studied. The antimicrobial effect was tested at pH 5 and pH 6.2 and at two different initial concentrations (10 3 or 10 6 CFU/mL). Results indicated that chitosan from both sources have antimicrobial activity, although the effect depended on the microorganism considered ( Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli O157:H7). Our results indicated that Salmonella was the most resistant bacteria, and that chitosan from insect was less active than chitosan from crustacean, especially against Salmonella . Another important factor on antimicrobial activity was the pH of the sample. When chitosan was added to a solution with a pH of 6.2 it was more active against Listeria and Escherichia coli , than at pH 5.00. Besides, the effect of chitosan appears to decrease with the incubation time, since some increases in counts were observed on E . coli and Salmonella after the 24 and 49 hours of incubation.

Over the last years, there has been an increasing number of proposals for the use of nanomaterials in medicine. The safety of novel technologies must be verified, prior to their clinical application. Pathology has much to contribute towards this end. In this study, we compared the in vivo toxicity effects of poly- (lactic-co-glycolic acid) nanoparticles with and without chitosan shell. Both nanoparticle types were loaded with curcumin. The nanoparticles were assessed in vitro for potential cytotoxicity with cell viability studies. For the in vivo test, 36 adult Wistar rats were used, four of which were the control group. The remaining 32 were divided into 2 groups, each of which was administered differentially coated drug carriers: (A) nanoparticles without chitosan coating and (B) nanoparticles with chitosan coating. For both groups, the subcutaneous route was used for administration. Each group was further divided into 2 sub-groups of 8 animals each. The animals of the first sub-groups were sacrificed 24 h after the injection and those of the second on the 7th day. The control group was also divided into 2 subgroups of 2 animals each. At the appointed post-administrative date, the rats were sacrificed, and specimens from the brain, liver, kidneys, heart, stomach, lungs, and from the skin at the injection site were collected and studied histopathologically. The evaluation of both in vitro and in vivo testing shows that nanoparticles with chitosan have significantly less, if any, toxic effects compared to those without chitosan.