Chemical synthesis of chitosan/silver nanocomposites films loaded with moxifloxacin: Their characterization and potential antibacterial activity

Zinc caproate: Ecofriendly synthesis, structural characterization, and antibacterial action

Disease-causing microorganisms such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are among the primary contributors to morbidity and mortality of diarrhea in humans. Considering the challenges associated with antibiotic use, including antimicrobial resistance, this study aimed to develop a novel zinc-based agent for bacterial inactivation. To this end, zinc caproate (ZnCA) was synthesized using caproic acid (CA) and zinc oxide (ZnO) in anhydrous ethanol via the solvothermal method. Structural characterization techniques, including Fourier-transform infrared spectroscopy, single crystal X-ray diffraction analysis, and nuclear magnetic resonance spectroscopy, revealed the bidentate bridging coordination of zinc atoms with CA. The resulting two-dimensional ZnCA network was found to be composed of a distinct lamellar pattern, without any evident inter-layer interactions. Powder X-ray diffraction analysis, elemental analysis, and melting point analysis confirmed that ZnCA had an average particle size of 1.320 µm, a melting point of 147.2 °C, and a purity exceeding 98 %. Remarkably, ZnCA demonstrated potent antibacterial activity against E. coli and S. aureus, which exceeded the antibacterial efficacy of ZnO. ZnCA exerted its antibacterial effects by inhibiting biofilm formation, disrupting cell membrane integrity, increasing cell membrane permeability, and altering intracellular Ca2+-Mg2+-ATPase activity. These findings highlight the potential of ZnCA as a promising antibiotic substitute for the treatment of diarrhea in humans.

An antibacterial nanoclay- and chitosan-based quad composite with controlled drug release for infected skin wound healing

Microbial infections of surgical sites and other wounds represent a major impediment for patients. Multifunctional low-cost dressings promoting tissue reparation while preventing infections are of great interest to medical professionals. Here, clay-based laponite nanodiscs (LAP) were loaded with the antibacterial drug kanamycin (KANA) before being embedded into a poly(lactic-co-glycolic acid) (PLGA) membrane and coated with the biopolymer chitosan (CS). Results indicated that these biocompatible materials combined the excellent capacity of LAP for controlled drug release with the mechanical robustness of PLGA and the antibacterial properties of CS as well as its hydrophilicity to form a composite highly suitable as an infection-preventing wound dressing. In vitro, PLGA/LAP/KANA/CS released drugs in a sustainable manner over 30 d, completely inhibited the growth of infectious bacteria, prompted the adhesion fibroblasts, and accelerated their proliferation 1.3 times. In vivo, the composite enabled the fast healing of infected full-thickness skin wounds with a 96.19 % contraction after 14 d. During the healing process, PLGA/LAP/KANA/CS stimulated re-epithelization, reduced inflammation, and promoted both angiogenesis and the formation of dense collagen fibers with an excellent final collagen volume ratio of 89.27 %. Thus, multifunctional PLGA/LAP/KANA/CS made of low-cost components demonstrated its potential for the treatment of infected skin wounds.

Enhancing wheat crop production with eco-friendly chitosan encapsulated nickel oxide nanocomposites: A safe and sustainable solution for higher yield

In this work, we looked at using nickel oxide (NiO) nanocomposites with chitosan encapsulation as a nano-primer to improve wheat crop output. A straightforward green precipitation procedure was used to create the nanocomposites, and they were then characterized using several methods. According to the findings, the chitosan-encapsulated NiO nanocomposites possessed a large surface area and were resilient to changes in pH. Following this, wheat seeds were primed with the nanocomposites, and under greenhouse circumstances, the impact on crop growth was assessed. The findings demonstrated that, in comparison to the control group, nanocomposites priming considerably enhanced wheat growth and germination rate up to 99 %. In comparison to untreated plants, the wheat plants treated with the nanocomposites primer had greater plant height i.e. shoot length (11.4 cm) and root length (10.3 cm), leaf area, and biomass accumulation. Further research into the mechanism underlying the priming effect of nanocomposites on wheat growth revealed that the nanocomposites enhanced nutrient absorption, photosynthesis, and stress tolerance in wheat plants. In conclusion, our research shows that chitosan-encapsulated NiO nanocomposites have the potential to improve wheat crop productivity in an environmentally benign and long-term manner, offering a viable strategy for sustainable farming.

Plasmonic nanoprobes on single AuNTs for evaluating and monitoring the dynamic release of 2D drug carriers

The use of nanomaterials in drug delivery has gained significant attention in recent years. In this project, we developed a novel localized surface plasmon resonance (LSPR) nanoprobe on single gold triangular nanoplates (AuNTs) for dynamic monitoring of the drug carrier release process. Graphene, as the drug carrier, could be immobilized on the AuNT surface through the π-π* stacking effect. Upon loading or releasing the model drug (doxorubicin, DOX), subtle changes in the local microenvironment's dielectric constant around the AuNTs induced notable red-shifts or blue-shifts in the LSPR scattering spectra of single AuNTs. Furthermore, the spectral shifts led to a continuous enhancement in the red channel of the dark field microscopy (DFM) images during the drug release process in vitro, demonstrating that the drug release system is not susceptible to potential confounding factors. These release kinetics results under different conditions could be well-fitted using the Higuchi desorption model, further proving that this nanoprobe could be employed for evaluating the controlled release ability of 2D nanocarriers. These findings are expected to inspire new ideas and technologies in the preparation of more effective drug carriers, making a significant contribution to the development of drug delivery nanosystems and nanomedicine.

Therapeutic Potential of Nanocarrier-Mediated Delivery of Phytoconstituents for Wound Healing: Their Current Status and Future Perspective

The treatment of wounds is a serious problem all over the world and imposes a huge financial burden on each and every nation. For a long time, researchers have explored wound dressing that speeds up wound healing. Traditional wound dressing does not respond effectively to the wound-healing process as expected. Therapeutic active derived from plant extracts and extracted bioactive components have been employed in various regions of the globe since ancient times for the purpose of illness, prevention, and therapy. About 200 years ago, most medical treatments were based on herbal remedies. Especially in the West, the usage of herbal treatments began to wane in the 1960s as a result of the rise of allopathic medicine. In recent years, however, there has been a resurgence of interest in and demand for herbal medicines for a number of reasons, including claims about their efficacy, shifting consumer preferences toward natural medicines, high costs and negative side effects of modern medicines, and advancements in herbal medicines brought about by scientific research and technological innovation. The exploration of medicinal plants and their typical uses could potentially result in advanced pharmaceuticals that exhibit reduced adverse effects. This review aims to present an overview of the utilization of nanocarriers in plant-based therapeutics, including its current status, recent advancements, challenges, and future prospects. The objective is to equip researchers with a comprehensive understanding of the historical background, current state, and potential future developments in this emerging field. In light of this, the advantages of nanocarriers based delivery of natural wound healing treatments have been discussed, with a focus on nanofibers, nanoparticles, nano-emulsion, and nanogels.

Anti-inflammatory effect of simvastatin by impeding TNF-α and interleukin-1ß pathways: antiangiogenic activity of simvastatin and simvastatin-loaded silver nanoparticles

PURPOSE

The present study was carried out to evaluate anti-inflammatory and antiangiogenic attributes of simvastatin and its nanofilms containing silver nanoparticles.

METHODS

Silver nanoparticles and simvastatin-loaded nanocomposite (SNSN) films were formulated by using polymeric solution (pectin + sericin) through casting solution method. Different in vitro and in vivo anti-inflammatory assays were performed. In addition, chick chorioallantoic membrane assay (CAM) was also employed for angiogenesis activity.

RESULTS

FTIR spectra of the film depicted the presence of intact simvastatin. Differential scanning calorimetry exhibited no endothermic expression in F9 film thermogram. The simvastatin release from all films exhibited a burst effect. Cotton-pellet induced granuloma model study showed that high dose of simvastatin and indomethacin produced comparable (p < 0.05) anti-inflammatory effect. Noteworthy, RT-PCR showed dose-dependent, anti-oedematous effect of simvastatin through downregulation of serum TNF-α and interleukin-1ß levels. While results of CAM assay exhibited remarkable anti-angiogenic potential of SNSN films showing dissolved blood vessels network macroscopically.

CONCLUSION

To reiterate, simvastatin and its SNSN films can add significant contribution to the field of biomedicines due to their promising anti-inflammatory and antiangiogenic properties, however, clinical studies are required to validate their commercial use.

Enhancing efficacy of existing antibacterials against selected multiple drug resistant bacteria using cinnamic acid-coated magnetic iron oxide and mesoporous silica nanoparticles

Developing new antibacterial drugs by using traditional ways is insufficient to meet existing challenges; hence, new strategies in the field of antibacterial discovery are necessary. An alternative strategy is to improve the efficacy of currently available antibiotics. Herein, the antibacterial efficacy of drugs (Cefixime, Sulfamethoxazole, and Moxifloxacin) and drug-loaded cinnamic acid-coated magnetic iron oxide and mesoporous silica nanoparticles (NPs) was elucidated versus Gram-negative bacteria (Pseudomonas aeruginosa, Klebsiella pneumoniae, neuropathogenic Escherichia coli K1 and Serratia marcescens) and Gram-positive bacteria (Methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Streptococcus pneumoniae, and Bacillus cereus). NPs were synthesized by co-precipitation and the Stöber method, and characterized by Fourier transform-infrared spectroscopy, Zetasizer, and Atomic force microscopy. Lactate dehydrogenase (LDH) assays were accomplished to determine drug cytotoxicity against human cells. Spherical NPs in the range of 118-362 nm were successfully synthesized. Antibacterial assays revealed that drugs conjugated with NPs portray enhanced bactericidal efficacies against multiple drug resistant bacteria compared to the drugs alone. Of note, Cefixime-conjugated NPs against Escherichia coli K1 and Methicillin- resistant Staphylococcus aureus, resulted in the complete eradication of all bacterial isolates tested at significantly lower concentrations compared to the antibiotics alone. Likewise, conjugation of Moxifloxacin resulted in the complete elimination of E. coli K1 and MRSA. Of note, nano-formulated drugs presented negligible cytotoxicity against human cells. These results depict potent, and enhanced efficacy of nano-formulated drugs against medically important bacteria and can be used as alternatives to current antibiotics. Future in vivo studies and clinical studies are warranted in prospective years to realize these expectations.

Anti-Inflammatory and Anti-Angiogenic Aattributes of Moringa olifera Lam. and its Nanoclay-Based Pectin-Sericin films

Background: Inflammation is a strong reaction of the non-specific natural immune system that helps to start protective responses against encroaching pathogens and develop typical immunity against intruding factors. However, prolonged inflammation may lead to chronic autoimmune diseases. For thousands of years, medicinal plants have served as an excellent source of treatment for chronic pathologies such as metabolic diseases.

Purpose: The present study aims to evaluate the anti-inflammatory and anti-angiogenic potential of Moringa olifera Lam. extract (MO) and Moringa-loaded nanoclay films.

Methods: The extract preparation was done through the maceration technique using absolute methanol (99.7%) and labelled as Mo. Me. Mo. Me-loaded nanoclay-based films were prepared by using pectin and sericin (Table 1). The in vitro studies characterized the film thickness, moisture, and phytochemical contents. The in vivo anti-inflammatory tests involved using a cotton pellet-induced granuloma model assay. In addition, the chick chorioallantoic membrane (CAM) assay was employed for angiogenesis activity.

Results: The phytochemical analysis of the extract confirmed the presence of alkaloids, glycosides, flavonoids and phytosterol. This extract contained quercetin in a large quantity. Cotton-pellet induced granuloma model study revealed a comparable (p > 0.05) effect of a high dose of Mo. Me (500 mg/kg) as compared with standard drug. Noteworthy, data obtained through the RT-PCR technique manifested the dose-dependent anti-oedematous effect of Moringa olifera via downregulation of TNF-α and interleukin-1ß. The findings of the CAM assay exhibited a remarkable anti-angiogenic activity of Mo. Me loaded nanoclay films, showing diffused vasculature network in the macroscopic snapshot.

Conclusion:Moringa olifera and its nanocomposite films have therapeutic potential against inflammation.

Preparation of Silver Ion Antimicrobial Dressings and Prevention and Treatment of Central Venous Catheter-Related Infection on Burn Wounds of Critically Burned Patients

To further understand the characteristics of Ag+ antimicrobial dressings and its application value in the prevention and treatment of infections in burn patients, in the study, the Ag+ gel dressings were prepared and their physical and chemical characteristics were analyzed, and relationship between the gel dressing and central venous catheter (CVC)-related infections was further explored. The results showed that silver nitrate was made into nano silver particles, and its structure was clearly visible under microscope, and nano silver was further applied to preparation of Ag+ antibacterial dressings. Fibrocytes were clearly visible in Ag+ gel dressing and arranged uniformly, which indicated that Ag+ gel dressing had good compatibility with biological materials and had no obvious toxicity. Further clinical trials showed that Ag+ gel dressing can effectively reduce CVC-related infections. From 1 to 4 weeks of the experiment, the bacterial infection rate in burn wounds and blood of the treatment group (TG), which applied Ag+ gel dressing, was lower than the control group (P < 0.05). During the treatment, the burn healing rate of the TG was also greatly higher than the control group (P < 0.05). In addition, the burn wound exudate in the TG was greatly less than the control group (P < 0.05). In summary, the Ag+ gel dressing prepared has good biological and physical and chemical properties, which have bright prospects in the prevention and treatment of burn wounds and CVC-related infections. This study provides an experimental basis for clinical application of Ag+ gel dressing.

High-Throughput Fabrication of Antibacterial Starch/PBAT/AgNPs@SiO2 Films for Food Packaging

In this current work, antimicrobial films based on starch, poly(butylene adipate-co-terephthalate) (PBAT), and a commercially available AgNPs@SiO₂ antibacterial composite particle product were produced by using a melt blending and blowing technique. The effects of AgNPs@SiO₂ at various loadings (0, 1, 2, 3, and 4 wt%) on the physicochemical properties and antibacterial activities of starch/PBAT composite films were investigated. AgNPs@SiO₂ particles were more compatible with starch than PBAT, resulting in preferential distribution of AgNPs@SiO₂ in the starch phase. Infusion of starch/PBAT composite films with AgNPs@SiO₂ marginally improved mechanical and water vapor barrier properties, while surface hydrophobicity increased as compared with films without AgNPs@SiO₂. The composite films displayed superior antibacterial activities against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The sample loaded with 1 wt% AgNPs@SiO₂ (SPA-1) showed nearly 90% inhibition efficiency on the tested microorganisms. Furthermore, a preliminary study on peach and nectarine at 53% RH and 24 °C revealed that SPA-1 film inhibited microbial spoilage and extended the product shelf life as compared with SPA-0 and commercial LDPE packaging materials. The high-throughput production method and strong antibacterial activities of the starch/PBAT/AgNPs@SiO₂ composite films make them promising as antimicrobial packaging materials for commercial application.

Chitosan-based nanocomposite films incorporated with NiO nanoparticles: Physicochemical, photocatalytic and antimicrobial properties

The aim of this research was to fabricate active nanocomposite films by incorporation of nickel oxide nanoparticles (NiONPs) (3, 6 and 9% w/w) into the chitosan-based films. The NiONPs were synthesized by solution combustion method and the films were prepared by solvent casting method. The formation of new interactions and increasing of films' crystallinity were confirmed by FT-IR and XRD analyses. Uniform dispersion of NiONPs at lower concentrations and their aggregation at level of 9% was confirmed by FE-SEM observations. Water barrier properties, tensile strength, thermal properties and surface hydrophobicity of films enhanced by addition of 6% NiONPs. Photocatalytic activity of nanocomposites was confirmed by absorption of 72% of methyl orange during 270 min under UV irradiation. The nanocomposite films exhibited good antibacterial activity against gram-positive (S. aureus) and gram-negative (S. typhimurium) bacteria. Therefore, the chitosan-NiONPs nanocomposite films could be used for active food packaging applications and photodecolorization purposes.

Moxifloxacin and Sulfamethoxazole-Based Nanocarriers Exhibit Potent Antibacterial Activities

Antibiotic resistance is a major concern given the rapid emergence of multiple-drug-resistant bacteria compared to the discovery of novel antibacterials. An alternative strategy is enhancing the existing available drugs. Nanomedicine has emerged as an exciting area of research, showing promise in the enhanced development of existing antimicrobials. Herein, we synthesized nanocarriers and loaded these with available clinically approved drugs, namely Moxifloxacin and Sulfamethoxazole. Bactericidal activity against Gram-negative (Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella enterica) and Gram-positive (methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, and Bacillus cereus) bacteria was investigated. To characterize the nanocarriers and their drug-loaded forms, Fourier-transform infrared spectroscopy, dynamic light scattering, and atomic force microscopy were utilized. Antibacterial assays and hemolysis assays were carried out. Moreover, lactate dehydrogenase assays were performed to determine cytotoxicity against human cells. The results depicted the successful formation of drug-nanocarrier complexes. The potent antibacterial activities of the drug-loaded nanocarriers were observed and were significantly enhanced in comparison to the drugs alone. Hemolysis and cytotoxicity assays revealed minimal or negligible cytotoxic effects against human red blood cells and human cells. Overall, metronidazole-based nanocarriers loaded with Moxifloxacin and Sulfamethoxazole showed enhanced bactericidal effects against multiple-drug-resistant bacteria compared with drugs alone, without affecting human cells. Our findings show that drug-loaded nanocarriers hold promise as potent chemotherapeutic drugs against multiple-drug-resistant bacteria.

Dual-drug delivery of Ag-chitosan nanoparticles and phenytoin via core-shell PVA/PCL electrospun nanofibers

Dual-drug delivery systems were constructed through coaxial techniques, which were convenient for the model drugs used the present work. This study aimed to fabricate core-shell electrospun nanofibrous membranes displaying simultaneous cell proliferation and antibacterial activity. For that purpose, phenytoin (Ph), a well-known proliferative agent, was loaded into a polycaprolactone (PCL) shell membrane, and as-prepared silver-chitosan nanoparticles (Ag-CS NPs), as biocidal agents, were embedded in a polyvinyl alcohol (PVA) core layer. The morphology, chemical composition, mechanical and thermal properties of the nanofibrous membranes were characterized by FESEM/STEM, FTIR and DSC. The coaxial PVA-Ag CS NPs/PCL-Ph nanofibers (NFs) showed more controlled Ph release than PVA/PCL-Ph NFs. There was notable improvement in the morphology, thermal, mechanical, antibacterial properties and cytobiocompatibility of the fibers upon incorporation of Ph and Ag-CS NPs. The proposed core-shell PVA/PCL NFs represent promising scaffolds for tissue regeneration and wound healing by the effective dual delivery of phenytoin and Ag-CS NPs.

Phytochemical delivery through nanocarriers: a review

In recent times, phytochemicals encapsulated or conjugated with nanocarriers for delivery to the specific sites have gained considerable research interest. Phytochemicals are mostly plant secondary metabolites which reported to be beneficial for human health and in disease theraphy. However, these compound are large size and polar nature of these compounds, make it difficult to cross the blood-brain barrier (BBB), endothelial lining of blood vessels, gastrointestinal tract and mucosa. Moreover, they are enzymatically degraded in the gastrointestinal tract. Therefore, encapsulation or conjugation of these compounds with nanocrriers could be an alternate way to enhance their bioefficacy by influencing their gastrointestinal stability, rate of absorption and dispersion. This review presents an overview of nanocarriers alternatives which improves therapeutic value and avoid toxicity, by releasing bioactive compounds specifically at target tissues with enhanced stability and bioavailability. Future investigations may emphasize on deciphering the structural changes in nanocarriers during digestion and absorption, the difference between in-vitro and in-vivo digestion simulations, and impact of nanocarriers on the metabolism of phytochemicals.

Synthesis, characteristics and medical applications of plant nanomaterials

The recent preparations of metal nanoparticles using plant extracts as reducing agents are summarized here. The synthesis and characterization of plant-metal nanomaterials and the progress in antibacterial and anti-inflammatory medical applications are detailed, providing a new vision for plant-based medical applications. The medical application of plant-metal nanoparticles is becoming a research hotspot. Compared with traditional preparation methods, the synthesis of plant-metal nanoparticles is less toxic and more eco-friendly, increasing application potential. Highly efficient plant-metal nanoparticles are usually smaller than 100 nm. This review describes the synthesis, characterization and bioactivities of gold- and silver-plant nanoparticles as examples and clearly explained their antibacterial and anticancer mechanisms. An analysis of actual cases shows that the synthetic method and type of plant extract affect the activities of the products.

Supramolecular aggregates of cyclodextrins with co-solvent modulate drug dispersion and release behavior of poorly soluble corticosteroid from chitosan membranes

In this study, the ability of different beta-cyclodextrins to facilitate homogeneous dispersion of triamcinolone acetonide (TA) into chitosan membranes is assessed. Drug loading was assessed through atomic force microscopy (AFM), scanning electron microscopy (MEV-FEG), and X-ray diffraction analyses. Drug interactions with the co-polymer were investigated with Fourier transform infrared spectroscopy, thermal analyses. Swelling assay, and in vitro drug release experiment were used to assess TA release behavior. Undispersed particles of drug were observed to remain in the simple chitosan membranes. Hydroxypropyl-β-cyclodextrin enabled the dispersion of TA into chitosan membranes and subsequent sustained drug release. In addition, the membrane performance as a drug delivery device is improved by adding specified amounts of the co-solvent triethanolamine. The experimental data presented in this study confirm the utility of our novel and alternative approach for obtaining a promising device for slow and controlled release of glucocorticoids, such as triamcinolone acetonide, for topical ulcerations.

Recent trends on wound management: New therapeutic choices based on polymeric carriers

Wound healing is an unmet therapeutic challenge among medical society since wound assessment and management is a complex procedure including several factors playing major role in healing process. Wounds can mainly be categorized as acute or chronic. It is well referred that the acute wound displays normal wound physiology while healing, in most cases, is seemed to progress through the normal phases of wound healing. On the other hand, a chronic wound is physiologically impaired. The main problem in wound management is that the majority of wounds are colonized with microbes, whereas this does not mean that all wounds will be infected. In this review, we address the problems that clinicians face to manage while treat acute and chronic wounds. Moreover, we demonstrate the pathophysiology, etiology, prognosis and microbiology of wounds. We further introduce the state of art in pharmaceutical technology field as part of wound management aiming to assist health professionals to overcome the current implications on wound assessment. In addition, authors review researches which included the use of gels and dermal films as wound healing agents. It can be said that natural and synthetic drugs or carriers provide promising solutions in order to meet the wound management standards. However, are the current strategies as desirable as medical society wish?

Facile synthesis of Ag nanoparticles-loaded chitosan antibacterial nanocomposite and its application in polypropylene

The development of environmental-friendly antibacterial agents with high efficiency and low cost has become the focus of attention. In this work, the Ag nanoparticles doped into chitosan (Ag NPs-CS) were synthesized by a green and facile method, and the samples were characterized by UV-Vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The antibacterial tests implied that Ag NPs-CS obtained from glucose (G-Ag NPs-CS) exhibited the excellent antimicrobial activities against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) microbes. Besides, the utilization of antibacterial agents in polymeric materials plays an significant role in healthy living. The aim is to impart the antibacterial properties and maintain/improve the mechanical properties. Therefore, the G-Ag NPs-CS with 5 wt% Ag was chosen as the optimal additive to endow polypropylene with antimicrobial activity via a simple melt blending method. The results demonstrated that the suppression of bacteria proliferation was enhanced with increasing the amount of antibacterial agent, and the microorganisms were almost killed when the content reached to 8 wt%. Meanwhile, the considerable improvement in elastic modulus and impact strength along with a slight decrease of elongation at break provided the evidence that Ag NPs-CS/PP nanocomposites were the promising candidate for practical applications.