Chitosan-based nanoparticles against bacterial infections

Physical stimuli-responsive polymeric patches for healthcare

Many chronic diseases have become severe public health problems with the development of society. A safe and efficient healthcare method is to utilize physical stimulus-responsive polymer patches, which may respond to physical stimuli, including light, electric current, temperature, magnetic field, mechanical force, and ultrasound. Under certain physical stimuli, these patches have been widely used in therapy for diabetes, cancer, wounds, hair loss, obesity, and heart diseases since they could realize controllable treatment and reduce the risks of side effects. This review sketches the design principles of polymer patches, including composition, properties, and performances. Besides, control methods of using different kinds of physical stimuli were introduced. Then, the fabrication methods and characterization of patches were explored. Furthermore, recent applications of these patches in the biomedical field were demonstrated. Finally, we discussed the challenges and prospects for its clinical translation. We anticipate that physical stimulus-responsive polymer patches will open up new avenues for healthcare by acting as a platform with multiple functions.

Exploring the antibiofilm potential of chitosan nanoparticles by functional modification with chloroquine and deoxyribonuclease

Planktonic bacteria tend to form sessile community architectures to shield resident bacteria from various environmental stresses. The formed biofilm leads to the failure of conventional antimicrobial therapy. Extracellular macromolecules, including extracellular DNA (eDNA), proteins, lipids, and polysaccharides, crosslink into gel-like structures through electrostatic forces in the mature biofilm matrix. The stereo-structural integrity and chemical inertia of the extracellular polymeric matrix result in comprehensive antimicrobial resistance to antibacterial polysaccharides. Herein, an ionic gelation method was employed to functionalize cationic chitosan nanoparticles (CSNPs) with chloroquine and deoxyribonuclease. The modification involved shifting eDNA chirality through a DNA-intercalating agent, chloroquine, and hydrolyzing an eDNA scaffold with deoxyribonuclease. The antibiofilm activity was assessed against a standard Staphylococcus aureus strain and clinical subtype isolates. Functional modifications targeting eDNA improved the chitosan anti-biofilm efficiency (residual biomass decreased from 74.2 to 90.3 % to 16.7-24.6 %) by disrupting the biofilm matrix. The functional CSNPs worked as a sensitizer prodrug, contributing to a bactericidal process of chitosan itself (cell wall damage increased from 11.38-18.16 % to 55.2-61.4 %) by dispersing the biofilm-enclosed bacteria. In vivo, the bacterial burden of infected mouse joints was reduced by 4.1 lg CFU/mL. Our results indicate the potential of this chitosan-based anti-infection strategy in biofilm-related infections.

Exploring the potential of chlorogenic acid/chitosan nanoparticle-loaded edible films with photodynamic technology for Mongolian cheese application

This study aimed to evaluate the efficiency of edible films made from chlorogenic acid/chitosan (CGA/CS) nanoparticles combined with photodynamic technology (PDT). Hydroxypropyl starch (HS) and κ-carrageenan (KC) were used as the main ingredients in the preservation of Mongolian cheese under the PDT condition. The mechanical characteristics, water vapor adsorption, solubility, permeability, and release of chlorogenic acid in aqueous media were evaluated. The incorporation of CGA/CS significantly enhanced the tensile strength and barrier characteristics of the edible films. The antimicrobial efficacy of the edible film was assessed over a period of 7 days while the cheese was being stored, followed by PDT application. The use of antimicrobial PDT did not cause lipid oxidation in cheese samples. Additionally, the combination of CGA/CS@HS/KC helped to reduce fat oxidation in Mongolian cheese. Utilizing an edible film in conjunction with PDT presents a viable solution for prolonging the shelf life of Mongolian cheese while maintaining its sensory attributes and nutritional qualities.

Optimization of preparation conditions for β-chitosan derived from diatom biomanufacturing using response surface methodology

Chitosan is a polymeric polysaccharide with widely application. At present, commercialized chitosan obtained by deacetylating chitin with acid-alkali method. The homogeneity of the molecular weight of chitosan is difficult to adjust due to the low homogeneity of chitosan itself and the degradation effect of the extraction process. And the single source of raw material has limited the further development of chitosan. In this study, diatoms were used as the source of chitosan extraction through alkalization freeze-thaw method, and response surface methodology was also used to optimize the best preparation conditions of diatom chitosan. The extracted chitosan from diatom was β-type chitosan with low molecular weight, great homogeneity. Diatom chitosan was able to reduce blood loss and clotting time >30 % in vivo experiment compared to control. The hemolysis rate of diatom chitosan was lower than 1 %, and the survival rate was higher than 95 % when co-cultured with L929 cells. Diatom chitosan with 0.005 % could inhibit E. coli and S. aureus by >90 %. Considering the large-scale cultivation properties of diatom, the extraction of diatom chitosan based on alkalization freeze-thaw method will provide a viable solution for obtaining β-chitosan with homogeneity on a large scale.

Anti-bacteria, anti-biofilm, and anti-virulence activity of the synthetic compound MTEBT-3 against carbapenem-resistant Klebsiella pneumoniae strains ST3984

PURPOSE

The rise of carbapenem-resistant Klebsiella pneumoniae (CRKP) has led to increased morbidity and mortality in clinical patients, highlighting the urgent need for effective antibacterial agents.

METHODS

We obtained a synthetic compound, MTEBT-3, using hydrophobic triphenylamine as the skeleton and hydrophilic ammonium salts. We determined the MIC of MTEBT-3 using the macro-broth susceptibility testing method. We isolated a clinical CRKP strain ST3984 and performed synergistic antibiotic sensitivity tests, time-kill assays, and resistance evolution studies. Biofilm formation under sub-MIC conditions was evaluated using crystal violet staining and CLSM. Additionally, biofilm proteins and polysaccharides were quantified. We assessed the bactericidal mechanism of MTEBT-3 by examining the integrity of CRKP bacterial cell membranes and analyzing the transcription of virulence-regulating genes via quantitative real-time PCR.

RESULTS

MTEBT-3 exhibited broad-spectrum antibacterial activity with a low resistance rate, achieving an MIC of 8 μg/mL. The compound displayed additive effects with meropenem and imipenem and synergistic effects with tigecycline. It maintained its efficacy over multiple bacterial generations, with no significant increase in resistance observed. Under sub-MIC conditions, the biomass of biofilms was significantly reduced, and the levels of proteins and polysaccharides within the biofilms were markedly lowered in a concentration-dependent manner. The bactericidal mechanism of MTEBT-3 involved disrupting the integrity of CRKP bacterial cell membranes, leading to increased permeability. Quantitative real-time PCR results showed that MTEBT-3 effectively suppressed the expression of key virulence genes, including fimH, wbbM, rmpA, and rmpA2, which are associated with biofilm formation and bacterial adhesion.

CONCLUSION

The significant antimicrobial activity of MTEBT-3 against clinically isolated CRKP, along with its synergistic or additive effects with commonly used antibiotics, positions it as a promising candidate for treatment. Its ability to disrupt biofilm formation and reduce virulence factor expression further underscores its potential in managing CRKP infections.

The attract-kill inhibition mechanism in Ag/chitosan hydrogel for long-acting control of Ralstonia solanacearum

In this study, we developed an innovative eco-friendly antiseptic nanocomposite, specifically a silver nanoparticle (Ag NP)-immobilized chitosan hydrogel (Ag@Cs/Csh gel), synthesized through a cross-linking reaction involving polyvinylpyrrolidone (PVP) and tetraethyl orthosilicate (TEOS). This nanocomposite was designed to combat Ralstonia solanacearum (R. solanacearum) infections, particularly in Solanaceae plants. Chitosan of varying molecular weights (50-190 kDa for Cs and 300-375 kDa for Csh) was used to control the swelling efficacy and regulate the release of Ag NPs. The gels were loaded with either 0.1 or 0.25 mg of Ag NPs and assessed for their antibacterial efficacy against R. solanacearum at various concentrations using the turbidity method. At 5 × 104 CFU mL-1, all gel samples, except for controls, exhibited notable antibacterial activity lasting up to 18.5 days. At higher concentrations of 5 × 106 and 5 × 108 CFU mL-1, the 0.25-Ag@Cs/Csh gel achieved nearly 100% eradication over 18.5 days. Notably, parallel experiments with various concentrations of Ag NPs alone showed limited antibacterial effectiveness against R. solanacearum. Therefore, we propose an "attract and kill" antibacterial mechanism to elucidate the enhanced disinfection capability of the Ag@Cs/Csh gel. Initially, the positively charged chitosan hydrogel attracts negatively charged bacteria, followed by steady Ag+ ion release to eradicate them, providing potent and prolonged antibacterial efficacy.

Chitosan-naphthalimide probes for dual channel recognition of HClO and H2S in cells and their application in photodynamic therapy

The combination of bio-imaging with photodynamic therapy (PDT) to accomplish theranostics is promising in cancer treatment. Three chitosan-naphthalimide probes were studied in this work. 4-(5-Bromothiophen-2-yl)-1,8-naphthalic anhydride was first synthesized, and then reacted with chitosan to obtain the macromolecules (CS-N-Br). The recognition group thiomorpholine or its derivatives were introduced into CS-N-Br to obtain nano-probes (CS-N-ML, CS-N-BSZ, CS-N-FSQ) eventually. The studies revealed that CS-N-ML and CS-N-FSQ exhibit high selectivity and can specifically recognize HClO and H2S. CS-N-ML and CS-N-FSQ can perform exogenous and endogenous confocal imaging of HClO and H2S in cells also. CS-N-ML's ability to target lysosomes positions indicated it could act as a lysosome-specific probe. It was discovered that the probes generate superoxide anions (O2•-) via a Type I mechanism. This discovery endows the probes with high photosensitizing activity even under hypoxic conditions. There is a positive correlation between the extent of the conjugated system and the photosensitivity of the probes, indicating that an enhanced conjugation leads to increased photosensitivity. Upon light irradiation, the probes generate ROS within HeLa cells. These results suggested that these probes can achieve theranostics for diseases associated with abnormal levels of HClO and H2S.

Research progress and application of chitosan dressings in hemostasis: A review

Hemorrhage affects human health, and severe bleeding remains a leading contributor to trauma-related mortality. The speed and effectiveness of the application of hemostatic materials are critical. Conventional hemostatic dressings such as bandages and gauze are gradually being replaced by new types of hemostatic dressings due to their poor hemostatic and antibacterial properties. Chitosan, a biopolymer, is biodegradable and nontoxic and possesses hemostatic and antibacterial properties. Chitosan induces hemostasis through direct contact with red corpuscles and platelets, independent of the coagulation pathways of the host, rendering it an optimal hemostatic dressing. It is widely used in wound care, particularly to stop bleeding, promote wound healing, and provide antimicrobial properties. This article reviews the recent research and development of chitosan-based hemostatic dressings, focusing on trauma hemostasis, burn hemostasis, diabetic skin ulcer hemostasis and other aspects. It also emphasizes the significance of chitosan dressings in wound hemostasis and healing, identifies their research opportunities in hemostasis and wound healing, and explores new research directions.

Ultrasound-assisted fabrication of chitosan-hydroxypropyl methylcellulose nanoemulsions loaded with thymol and cinnamaldehyde: Physicochemical properties, stability, and antifungal activity

This study investigated the influence of chitosan (CH) and hydroxypropyl methylcellulose (H), along with ultrasound power, on the physicochemical properties, antifungal activity, and stability of oil-in-water (O/W) nanoemulsions containing thymol and cinnamaldehyde in a 7:3 (v/v) ratio. Eight O/W formulations were prepared using CH, H, and a 1:1 (v/v) blend of CH and H, both with and without ultrasonication (U). Compared to untreated samples, U-treated nanoemulsions had lower droplet sizes (433-301 nm), polydispersity index (0.42-0.47), and zeta potential (-0.42-0.77 mV). The U treatment decreased L* and b* values, increased a* color attribute values, and increased apparent viscosity (0.26-2.17) at the same shear rate. After 28 days, microbiological testing of nanoemulsions treated with U showed counts below the detection limits (< 2 log CFU mL-1). The U-treated nanoemulsions exhibited stronger antifungal effects against R. stolonifer, with the NE/CH-U and NE/CH-H-U formulations demonstrating the lowest minimum inhibitory and fungicidal concentrations, measured at 0.12 and 0.24 μL/mL, respectively. On day 28, U-treated nanoemulsions demonstrated higher ionic, thermal, and physical stability than untreated samples. These findings suggest that the stability and antifungal efficacy of polysaccharide-based nanoemulsions may be improved by ultrasonic treatment. This study paves the way for innovative, highly stable nanoemulsions.

Zein nanoparticles extend lifespan in C. elegans and SAMP8 mice

Empty zein nanoparticles (NP) have been shown to lower glycemia in rats by stimulating the secretion of endogenous GLP-1. This study evaluated the effect of these nanoparticles on the lifespan of two animal models: C. elegans fed with a glucose-rich diet and the senescence accelerated mouse-prone 8 (SAMP8 mice). In C. elegans, NP increased the mean lifespan of worms by 7 days (from 17.1 for control to 24.5 days). This observation was in line with the observed significant reductions of glucose and fat contents, lipofuscin accumulation, and ROS expression. Furthermore, NP supplementation led to an upregulation of the expression of daf-16 and skn-1 genes. DAF-16 (orthologue of the FOXO family) and SKN-1 (orthologue of mammalian Nrf/CNC proteins) are implicated in activating detoxification mechanisms against oxidative damage. In SAMP8, oral administration of NP also extended the mean lifespan of mice (by 28 % compared to controls), corroborating the protective effect of these nanoparticles.

Immunization with the glutathione S-transferase Sj26GST with Chi-CpG NP against Schistosoma japonicum in mice

Schistosomiasis caused by Schistosoma japonicum (S. japonicum) is a major public health problem in the Philippines, China and Indonesia. In this study, the immunopotentiator CpG-ODN was encapsulated within chitosan nanoparticles (Chi NPs) to create a combination adjuvant (Chi-CpG NP). This approach was employed to enhance the immunogenicity of 26 kDa glutathione S-transferase (Sj26GST) from S. japonicum through intranasal immunization. The results demonstrated higher levels of specific anti-Sj26GST antibodies and Sj26GST-specific splenocyte proliferation compared to mice that were immunized with Sj26GST + Chi-CpG NP. Cytokine analysis of splenocytes revealed that the Sj26GST + Chi-CpG NP induced a slight Th1-biased immune response, with increased production of IFN-γ by CD4+ T-cells in the spleen. Subsequently, mice were intradermally inoculated with 1 × 107 organisms in the Coeliac cavity. The bacterial organ burden detected in the liver of immunized mice suggested that Sj26GST + Chi-CpG NP enhances protective immunity to inhibit S. japonicum colonization. Therefore, Sj26GST + Chi-CpG NP vaccination enhances Sj26GST-specific immunogenicity and provides protection against S. japonicum.

Advancements of Porphyrin-Derived Nanomaterials for Antibacterial Photodynamic Therapy and Biofilm Eradication

The threat posed by antibiotic-resistant bacteria and the challenge of biofilm formation has highlighted the inadequacies of conventional antibacterial therapies, leading to increased interest in antibacterial photodynamic therapy (aPDT) in recent years. This approach offers advantages such as minimal invasiveness, low systemic toxicity, and notable effectiveness against drug-resistant bacterial strains. Porphyrins and their derivatives, known for their high molar extinction coefficients and singlet oxygen quantum yields, have emerged as crucial photosensitizers in aPDT. However, their practical application is hindered by challenges such as poor water solubility and aggregation-induced quenching. To address these limitations, extensive research has focused on the development of porphyrin-based nanomaterials for aPDT, enhancing the efficacy of photodynamic sterilization and broadening the range of antimicrobial activity. This review provides an overview of various porphyrin-based nanomaterials utilized in aPDT and biofilm eradication in recent years, including porphyrin-loaded inorganic nanoparticles, porphyrin-based polymer assemblies, supramolecular assemblies, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). Additionally, insights into the prospects of aPDT is offered, highlighting its potential for practical implementation.

Designing antibacterial materials through simulation and theory

Antibacterial materials have a wide range of potential applications in bio-antimicrobial, environmental antimicrobial, and food antimicrobial fields due to their intrinsic antimicrobial properties, which can circumvent the development of drug resistance in bacteria. Understanding the intricate mechanisms and intrinsic nature of diverse antibacterial materials is significant for the formulation of guidelines for the design of materials with rapid and efficacious antimicrobial action and a high degree of biomedical material safety. Herein, this review highlights the recent advances in investigating antimicrobial mechanisms of different antibacterial materials with a particular focus on tailored computer simulations and theoretical analysis. From the view of structure and function, we summarize the characteristics and mechanisms of different antibacterial materials, introduce the latest advances of new antibacterial materials, and discuss the design concept and development direction of new materials. In addition, we underscore the significance of employing simulation and theoretical methodologies to elucidate the intrinsic antimicrobial mechanisms, which is crucial for a comprehensive comprehension of the control strategies, safer biomedical applications, and the management of health and environmental concerns associated with antibacterial materials. This review could potentially stimulate further endeavors in fundamental research and facilitate the extensive utilization of computational and theoretical approaches in the design of novel functional nanomaterials.

Formulation and optimization of surfactant-modified chitosan nanoparticles loaded with cefdinir for novel topical drug delivery: Elevating wound healing efficacy with enhanced antibacterial properties

Burn wounds remain a significant global health concern, frequently exacerbated by bacterial infections that hinder healing and raise morbidity rates. Cefdinir, a third-generation cephalosporin antibiotic, is used to treat various conditions, but it has limitations such as low water solubility, limited bioavailability, and a short biological half-life. This study aimed to fabricate and optimize novel surfactant-based Cefdinir-loaded chitosan nanoparticles (CFD-CSNPs) for enhancing topical CFD delivery and efficacy in burn healing. Box-Behnken Design (BBD) was employed to develop optimized CFD-CSNPs using Design Expert® software, where the independent factors were chitosan concentration, chitosan: sodium tripolyphosphate ratio, pH, and surfactant type. Particle size PS, zeta potential ZP, Polydispersity index PDI, and entrapment efficiency EE% were evaluated as dependent factors. CFD-CSNPs were produced using the ionic gelation method. The optimized formula was determined and then examined for further in vitro and in vivo assessments. The optimized CFD-CSNPs exhibited acceptable PS, PDI, and ZP values. The EE% of CFD from CSNPs reached 57.89 % ± 1.66. TEM analysis revealed spherical morphology. In vitro release studies demonstrated a biphasic release profile up to (75.5 % ± 3.8) over 48 hrs. The optimized CFD-CSNPs showed improved antimicrobial efficacy against the tested microorganisms, exhibiting superior performance for both biofilm prevention and eradication. Enhanced wound healing activity was achieved by the optimized CFD-CSNPs in both in vitro and in vivo studies as confirmed by scratch wound assay and skin burn mice model. The current study advocates the efficacy of the innovative topical application of CFD-CSNPs for wound healing purposes and treatment of wound infections.

Recent advances on chitosan/hyaluronic acid-based stimuli-responsive hydrogels and composites for cancer treatment: A comprehensive review

Cancer, as leading cause of death, has a high rate of mortality worldwide. Although there is a wide variety of conventional approaches for the treatment of cancer (such as surgery and chemotherapy), they have considerable drawbacks in terms of practicality, treatment efficiency, and cost-effectiveness. Therefore, there is a fundamental requirement for the development of safe and efficient treatment modalities based on breakthrough technologies to suppress cancer. Chitosan (CS) and hyaluronic acid (HA) polysaccharides, as FDA-approved biomaterials for some biomedical applications, are potential biopolymers for the efficient treatment of cancer. CS and HA have high biocompatibility, bioavailability, biodegradability, and immunomodulatory function which guarantee their safety and non-toxicity. CS-/HA-based hydrogels (HGs)/composites stand out for their potential anticancer function, versatile preparation and modification, ease of administration, controlled/sustained drug release, and active and passive drug internalization into target cells which is crucial for efficient treatment of cancer compared with conventional treatment approaches. These HGs/composites can respond to external (magnetic, ultrasound, light, and thermal) and internal (pH, enzyme, redox, and ROS) stimuli as well which further paves the way to their manipulation, targeted drug delivery, practicality, and efficient treatment. The above-mentioned properties of CS-/HA-based HGs/composites are unique and practical in cancer treatment which can ignore the deficiencies of conventional approaches. The present manuscript comprehensively highlights the advances in the practical application of stimuli-responsive HGs/composites based on CS/HA polysaccharides.

Investigation on novel chitin and chitosan from dung beetle Heteronitis castelnaui (Harold, 1865) and its potential application for organic dyes removal from aqueous solution

Chitosan, a natural polysaccharide, has attracted considerable attention as an environmentally friendly and highly efficient adsorbent for dye removal. It is usually produced by deacetylation or partial deacetylation of chitin. However, conventional sources of chitin and chitosan are limited, prompting the need for alternative sources with improved adsorption capabilities. Herein, this study focuses on exploring a novel chitin and chitosan source derived from the dung beetle and evaluates its potential for organic dye removal from aqueous solutions. The research involves the extraction and characterization of chitin and chitosan from dung beetle Heteronitis castelnaui (Harold, 1865) using various analytical techniques, including SEM, FT-IR, TGA, XRD, NMR, deacetylation degree and elemental analysis. The chitosan obtained was used for the formation of hydrogels with sodium alginate via cross-linking with calcium chloride. And then the prepared hydrogels were evaluated for its adsorption capacity through batch adsorption experiments using methylene blue as a model pollutant. The adsorption capacity for methylene blue was 1294.3 mg/g at room temperature with solution pH = 12, MB concentration of 1800 mg/L. Furthermore, the kinetics of the adsorption process were analyzed using pseudo-first-order and pseudo-second-order models to understand the rate of adsorption. The maximum adsorption capacities were determined using Langmuir and Freundlich isotherm models. This study provides valuable insights for the development of sustainable dye adsorption technologies, specifically investigating a novel chitosan source derived from the dung beetle.

Applications of Chitosan in Prevention and Treatment Strategies of Infectious Diseases

Chitosan is the most commonly investigated functional cationic biopolymer in a wide range of medical applications due to its promising properties such as biocompatibility, biodegradability, and bioadhesivity, as well as its numerous bioactive properties. Within the last three decades, chitosan and its derivatives have been investigated as biomaterials for drug and vaccine delivery systems, besides for their bioactive properties. Due to the functional groups in its structure, it is possible to tailor the delivery systems with desired properties. There has been a great interest in the application of chitosan-based systems also for the prevention and treatment of infectious diseases, specifically due to their antimicrobial, antiviral, and immunostimulatory effects. In this review, recent applications of chitosan in the prevention and treatment of infectious diseases are reviewed, and possibilities and limitations with regards to technical and regulatory aspects are discussed. Finally, the future perspectives on utilization of chitosan as a biomaterial are discussed.

Novel Functional Dressing Materials for Intraoral Wound Care

Intraoral wounds represent a particularly challenging category of mucosal and hard tissue injuries, characterized by the unique structures, complex environment, and distinctive healing processes within the oral cavity. They have a common occurrence yet frequently inflict significant inconvenience and pain on patients, causing a serious decline in the quality of life. A variety of novel functional dressings specifically designed for the moist and dynamic oral environment have been developed and realized accelerated and improved wound healing. Thoroughly analyzing and summarizing these materials is of paramount importance in enhancing the understanding and proficiently managing intraoral wounds. In this review, the particular processes and unique characteristics of intraoral wound healing are firstly described. Up-to-date knowledge of various forms, properties, and applications of existing products are then intensively discussed, which are categorized into animal products, plant extracts, natural polymers, and synthetic products. To conclude, this review presents a comprehensive framework of currently available functional intraoral wound dressings, with an aim to provoke inspiration of future studies to design more convenient and versatile materials.

Composite Mineralized Collagen/Polycaprolactone Scaffold-Loaded Microsphere System with Dual Osteogenesis and Antibacterial Functions

Biomaterials play an important role in treating bone defects. The functional characteristics of scaffolds, such as their structure, mechanical strength, and antibacterial and osteogenesis activities, effectively promote bone regeneration. In this study, mineralized collagen and polycaprolactone were used to prepare loaded porous scaffolds with bilayer-structured microspheres with dual antibacterial and osteogenesis functions. The different drug release mechanisms of PLGA and chitosan in PLGA/CS microspheres caused differences in the drug release models in terms of the duration and rate of Pac-525 and BMP-2 release. The prepared PLGA(BMP-2)/CS(Pac-525)@MC/PCL scaffolds were analyzed in terms of physical characteristics, bioactivity, and antibacterial properties. The scaffolds with a dimensional porous structure showed similar porosity and pore diameter to cancellous bone. The release curve of the microspheres and scaffolds with high encapsulation rates displayed the two-stage release of Pac-525 and BMP-2 over 30 days. It was found that the scaffolds could inhibit S. aureus and E. coli and then promote ALP activity. The PLGA(BMP-2)/CS(Pac-525)@MC/PCL scaffold could be used as a dual delivery system to promote bone regeneration.

PLGA Nanoparticles Formulations Loaded With Antibiotics Induce Sustained and Controlled Antibiotics Release for Prolonged Antibacterial Action Against MRSA, and Pseudomonas aeruginosa FRD1

The purpose of the present study was to create resorbable nanoparticles (NPs) using poly(lactic-co-glycolic acid) (PLGA) to develop novel antibacterial therapeutics for the treatment of chronic wound infections that are susceptible to recurrent infections. By first performing a release study, it was possible to predict the behavior of the different PLGA NP formulations and assess the efficacy of the nanocomposite drug delivery system. These PLGA NP formulations consisted of varying ratios of PLGA without polyvinyl alcohol (PVA) and PLGA with PVA (PLGA-PVA) (i.e., 25:75[PLGA25], 50:50[PLGA50], and 75:25[PLGA75]). Then, different antibiotics (i.e., ciprofloxacin and gentamicin) were incorporated into the PLGA NP formulations to test the antibacterial efficacy of these antimicrobial NPs against different pathogens (i.e., methicillin-resistant Staphylococcus aureus USA300 [MRSA], Pseudomonas aeruginosa FRD1, and Acinetobacter baumannii BAA1605). Of particular interest was testing against the MRSA strain USA300 and the P. aeruginosa strain FRD1. This was possible by measuring the zone of inhibition. A 3-day period was used to monitor the antibacterial efficacy of the different PLGA NP formulations (i.e., PLGA25, PLGA50, and a 1:1 combination of PLGA25:PLGA50) against A. baumannii BAA1605, MRSA, and P aeruginosa FRD1. Throughout the study, A. baumannii was a negative control and was resistant to all the PLGA NP formulations loaded with ciprofloxacin and gentamicin. At the end of the 3-day period, the PLGA and PLGA50 ciprofloxacin-loaded formulations produced zones of inhibition of 27 mm and 23 mm, respectively, against P. aeruginosa FRD1. This indicated that P. aeruginosa FRD1 was susceptible to both formulations. The mixed formulations with equal parts PLGA25:PLGA50 loaded with ciprofloxacin produced a zone of inhibition (i.e., 25 mm). This again indicated that P. aeruginosa FRD1 was susceptible to ciprofloxacin. The formulations tested against MRSA showed that only gentamicin-loaded formulations produced intermediate results, and that ciprofloxacin-loaded formulations were ineffective. The PLGA25 and the PLGA50 NP formulations loaded with gentamicin both produced zones of inhibition of 13 mm. This indicated that MRSA was intermediate to both the formulations. The PLGA25:PLGA50 loaded with gentamicin produced a zone of inhibition of 14 mm, which again showed that MRSA was intermediate to this formulation. Overall, these PLGA NP formulations showed the sustained antibacterial potential of a burst release, followed by a sustained release of antibiotics from antibiotics loaded PLGA NPs in a controlled manner. In the future, this can help prevent the emergence of recurrent infections in the treatment of chronic wounds and reduce the number of medical dressing changes.

Influence of Physicochemical Properties of Iron Oxide Nanoparticles on Their Antibacterial Activity

The increasing occurrence of infectious diseases caused by antimicrobial resistance organisms urged the necessity to develop more potent, selective, and safe antimicrobial agents. The unique magnetic and tunable properties of iron oxide nanoparticles (IONPs) make them a promising candidate for different theragnostic applications, including antimicrobial agents. Though IONPs act as a nonspecific antimicrobial agent, their antimicrobial activities are directly or indirectly linked with their synthesis methods, synthesizing precursors, size, shapes, concentration, and surface modifications. Alteration of these parameters could accelerate or decelerate the production of reactive oxygen species (ROS). An increase in ROS role production disrupts bacterial cell walls, cell membranes, alters major biomolecules (e.g., lipids, proteins, nucleic acids), and affects metabolic processes (e.g., Krebs cycle, fatty acid synthesis, ATP synthesis, glycolysis, and mitophagy). In this review, we will investigate the antibacterial activity of bare and surface-modified IONPs and the influence of physiochemical parameters on their antibacterial activity. Additionally, we will report the potential mechanism of IONPs' action in driving this antimicrobial activity.

Application of biomaterials in the treatment of intracerebral hemorrhage

Although the current surgical hematoma removal treatment saves patients' lives in critical moments of intracerebral hemorrhage (ICH), the lethality and disability rates of ICH are still very high. Due to the individual differences of patients, postoperative functional improvement is still to be confirmed, and the existing drug treatment has limited benefits for ICH. Recent advances in biomaterials may provide new ideas for the therapy of ICH. This review first briefly describes the pathogenic mechanisms of ICH, including primary and secondary injuries such as inflammation and intracerebral edema, and briefly describes the existing therapeutic approaches and their limitations. Secondly, existing nanomaterials and hydrogels for ICH, including exosomes, liposomes, and polymer nanomaterials, are also described. In addition, the potential challenges and application prospects of these biomaterials for clinical translation in ICH treatment are discussed.

Green synthesis of chitosan gum acacia based biodegradable polymeric nanoparticles to enhance curcumin's antioxidant property: an in vivo zebrafish (Danio rerio) study

Green-synthesis of biodegradable polymeric curcumin-nanoparticles using affordable biodegradable polymers to enhance curcumin's solubility and anti-oxidative potential. The curcumin-nanoparticle was prepared based on the ionic-interaction method without using any chemical surfactants, and the particle-size, zeta-potential, surface-morphology, entrapmentefficiency, and in-vitro drug release study were used to optimise the formulation. The antioxidant activity was investigated using H2DCFDA staining in the zebrafish (Danio rerio) model. The mean-diameter of blank nanoparticles was 178.2 nm (±4.69), and that of curcuminnanoparticles was about 227.7 nm (±10.4), with a PDI value of 0.312 (±0.023) and 0.360 (±0.02). The encapsulation-efficacy was found to be 34% (±1.8), with significantly reduced oxidative-stress and toxicity (∼5 times) in the zebrafish model compared to standard curcumin. The results suggested that the current way of encapsulating curcumin using affordable, biodegradable, natural polymers could be a better approach to enhancing curcumin's water solubility and bioactivity, which could further be translated into potential therapeutics.

Lipid-based nanosystems for wound healing

INTRODUCTION

Wounds, resulting from traumas, surgery, burns or diabetes, are important medical problems due to the complexity of wound healing process regarding healing times and healthcare costs. Nanosystems have emerged as promising candidates in this field thank to their properties and versatile applications in drugs delivery.

AREAS COVERED

Lipid-based nanosystems (LBN) are described for wound treatment, highlighting their different behaviors when interacting with the cutaneous tissue. The role of nanosystems in delivering mostly natural compounds on skin as well as the technological and engineering strategies to increase their efficiency in wound healing effect are reviewed. Finally, in vitro, ex-vivo and in vivo studies are reported.

EXPERT OPINION

LBN have shown promise in addressing the challenges of wound healing as they can improve the stability of drugs used in wound therapy, leading to higher efficacy and fewer adverse effects as compared to traditional formulations. LBNs being involved in the inflammatory and proliferation stages of the wound healing process, enable the modification of wound healing through multiple ways. In addition, the use of new technologies, including 3D bioprinting and photobiomodulation, may lead to potential breakthroughs in wound healing. This would provide clinicians with more potent forms of therapy for wound healing.

Advanced Dental Care: β-Chitosan Zinc Oxide Nanoparticles Targeting Cariogenic Microorganisms

Introduction Dental caries, primarily caused by cariogenic microorganisms, remains a significant global health concern. β-Chitosan, known for its biofilm-targeting properties, and zinc oxide (ZnO) nanoparticles (NPs), recognized for their potent antimicrobial effects, offer a promising approach for caries prevention and treatment. This study investigates the synthesis, characterization, and antimicrobial properties of β-Chitosan-derived ZnO NPs (β-Ch-ZnO-NPs) against these pathogens. Methodology β-Chitosan from fresh squid bones was isolated using demineralization and deproteinization methods. β-Ch-ZnO-NPs were synthesized and characterized using UV-vis spectroscopy and Fourier-transform infrared spectroscopy (FTIR) to confirm their size, shape, and stability. Antibacterial efficacy(agar well plate method)was assessed through standardized assays, demonstrating significant inhibition of cariogenic bacteria. The results were represented as mean± standard deviation. The Kruskal-Wallis test with post hoc analysis (Mann-Whitney U test) was conducted for statistical analysis. Molecular docking studies (blind docking method) were conducted to elucidate the interactions between β-Ch-ZnO-NPs and key bacterial enzymes involved in microbial genetic material synthesis, also known as dihydroorotate dehydrogenase (DHODH, PDB ID-2J0Y). Results The synthesized β-Ch-ZnO-NPs exhibited well-defined characteristics verified by UV-vis spectroscopy and FTIR confirming their nanoparticulate nature and stability. The antimicrobial effects of Streptomycin (50 µg/mL) and β-Ch-ZnO-NPs were compared across various microorganisms. β-Ch-ZnO-NPs at 100 µg/mL consistently showed larger inhibition zones than Streptomycin and β-Ch-ZnO-NPs at 50 µg/mL against Escherichia coli​​, Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, and Candida albicans.This suggests that β-Ch-ZnO-NPs at a higher concentration have potent antimicrobial activity across a broad spectrum of pathogens, highlighting their potential as effective antimicrobial agents. Kruskal-Wallis test showed statistically significant differences (P < 0.001) for all microbes, and post hoc analysis (Mann-Whitney U test) confirmed the P-value was less than 0.05. Molecular docking studies indicated strong binding affinities between β-Ch-ZnO-NPs and bacterial enzymes crucial for biofilm formation, suggesting inhibition of enzyme activity critical for bacterial virulence and survival. Conclusions This study highlights the synergistic potential of β-Chitosan and zinc oxide NPs in combating dental caries. The synthesized β-Ch-ZnO-NPs demonstrated effective antimicrobial activity against cariogenic microorganisms, attributed to their ability to disrupt bacterial metabolism and inhibit biofilm formation. Molecular docking analysis provided mechanistic insights into how β-Ch-ZnO-NPs interact with bacterial enzymes, reinforcing their role in impeding biofilm development. Overall, the findings support using β-Ch-ZnO-NPs as a promising therapeutic strategy for preventing and treating dental caries, leveraging their combined biofilm-targeting capabilities and antimicrobial effects.

Chitosan-Based Hydrogels as Antibacterial/Antioxidant/Anti-Inflammation Multifunctional Dressings for Chronic Wound Healing

Due to repeated microbial infection, persistent inflammation, excessive oxidative stress, and cell dysfunction, chronic wounds are difficult to heal, posing a serious threat to public health. Therefore, developing multifunctional wound dressings that can regulate the complex microenvironment of chronic wounds and enhance cellular function holds great significance. Recently, chitosan has emerged as a promising biopolymer for wound healing due to its excellent biocompatibility, biodegradability, and versatile bioactivity. The aim of this review is to provide a comprehensive understanding of the mechanisms of delayed chronic wound healing and discuss the healing-promoting properties of chitosan and its derivatives, such as good biocompatibility, antibacterial activity, hemostatic capacity, and the ability to promote tissue regeneration. On this basis, the potential applications of chitosan-based hydrogels are summarized in chronic wound healing, including providing a suitable microenvironment, eliminating bacterial infections, promoting hemostasis, inhibiting chronic inflammation, alleviating oxidative stress, and promoting tissue regeneration. In addition, the concerns and perspectives for the clinical application of chitosan-based hydrogels are also discussed.

Albumin Nanoparticle-Based Drug Delivery Systems

Nanoparticle-based systems are extensively investigated for drug delivery. Among others, with superior biocompatibility and enhanced targeting capacity, albumin appears to be a promising carrier for drug delivery. Albumin nanoparticles are highly favored in many disease therapies, as they have the proper chemical groups for modification, cell-binding sites for cell adhesion, and affinity to protein drugs for nanocomplex generation. Herein, this review summarizes the recent fabrication techniques, modification strategies, and application of albumin nanoparticles. We first discuss various albumin nanoparticle fabrication methods, from both pros and cons. Then, we provide a comprehensive introduction to the modification section, including organic albumin nanoparticles, metal albumin nanoparticles, inorganic albumin nanoparticles, and albumin nanoparticle-based hybrids. We finally bring further perspectives on albumin nanoparticles used for various critical diseases.

In vivo Fate of Targeted Drug Delivery Carriers

This review aimed to systematically investigate the intracellular and subcellular fate of various types of targeting carriers. Upon entering the body via intravenous injection or other routes, a targeting carrier that can deliver therapeutic agents initiates their journey. If administered intravenously, the carrier initially faces challenges presented by the blood circulation before reaching specific tissues and interacting with cells within the tissue. At the subcellular level, the car2rier undergoes processes, such as drug release, degradation, and metabolism, through specific pathways. While studies on the fate of 13 types of carriers have been relatively conclusive, these studies are incomplete and lack a comprehensive analysis. Furthermore, there are still carriers whose fate remains unclear, underscoring the need for continuous research. This study highlights the importance of comprehending the in vivo and intracellular fate of targeting carriers and provides valuable insights into the operational mechanisms of different carriers within the body. By doing so, researchers can effectively select appropriate carriers and enhance the successful clinical translation of new formulations.

Spider minor ampullate silk protein nanoparticles: an effective protein delivery system capable of enhancing systemic immune responses

Spider silk proteins (spidroins) are particularly attractive due to their excellent biocompatibility. Spider can produce up to seven different types of spidroins, each with unique properties and functions. Spider minor ampullate silk protein (MiSp) might be particularly interesting for biomedical applications, as the constituent silk is mechanically strong and does not super-contract in water, attributed to its amino acid composition. In this study, we evaluate the potential of recombinant nanoparticles derived from Araneus ventricosus MiSp as a protein delivery carrier. The MiSp-based nanoparticles were able to serve as an effective delivery system, achieving nearly 100% efficiency in loading the model protein lysozyme, and displayed a sustained release profile at physiological pH. These nanoparticles could significantly improve the delivery efficacy of the model proteins through different administration routes. Furthermore, nanoparticles loaded with model protein antigen lysozyme after subcutaneous or intramuscular administration could enhance antigen-specific immune responses in mouse models, through a mechanism involving antigen-depot effects at the injection site, long-term antigen persistence, and efficient uptake by dendritic cells as well as internalization by lymph nodes. These findings highlight the transnational potential of MiSp-based nanoparticle system for protein drug and vaccine delivery.

All-in-one hydrogel patches with sprayed bFGF-loaded GelMA microspheres for infected wound healing studies

The current wound healing process faces numerous challenges such as bacterial infection, inflammation and oxidative stress. However, wound dressings used to promote wound healing, are not well suited to meet the clinical needs. Hyaluronic acid (HA) not only has excellent water absorption and good biocompatibility but facilitates cell function and tissue regeneration. Dopamine, on the other hand, increases the overall viscosity of the hydrogel and possesses antioxidant property. Furthermore, chitosan exhibits outstanding performance in antimicrobial, anti-inflammatory and antioxidant activities. Basic fibroblast growth factor (bFGF) is conducive to cell proliferation and migration, vascular regeneration and wound healing. Hence, we designed an all-in-one hydrogel patch containing dopamine and chitosan framed by hyaluronic acid (HDC) with sprayed gelatin methacryloyl (GelMA) microspheres loaded with bFGF (HDC-bFGF). The hydrogel patch exhibits excellent adhesive, anti-inflammatory, antioxidant and antibacterial properties. In vitro experiments, the HDC-bFGF hydrogel patch not only showed significant inhibitory effect on RAW cell inflammation and Staphylococcus aureus (S. aureus) growth but also effectively scavenged free radicals, in addition to promoting the migration of 3 T3 cells. In the mice acute infected wound model, the HDC-bFGF hydrogel patch adhered to the wound surface greatly accelerated the healing process via its anti-inflammatory and antioxidant activities, bacterial inhibition and pro-vascularization effects. Therefore, the multifunctional HDC-bFGF hydrogel patch holds great promise for clinical application.

Unveiling the Druggable Landscape of Bacterial Peptidyl tRNA Hydrolase: Insights into Structure, Function, and Therapeutic Potential

Bacterial peptidyl tRNA hydrolase (Pth) or Pth1 emerges as a pivotal enzyme involved in the maintenance of cellular homeostasis by catalyzing the release of peptidyl moieties from peptidyl-tRNA molecules and the maintenance of a free pool of specific tRNAs. This enzyme is vital for bacterial cells and an emerging drug target for various bacterial infections. Understanding the enzymatic mechanisms and structural intricacies of bacterial Pth is pivotal in designing novel therapeutics to combat antibiotic resistance. This review provides a comprehensive analysis of the multifaceted roles of Pth in bacterial physiology, shedding light on its significance as a potential drug target. This article delves into the diverse functions of Pth, encompassing its involvement in ribosome rescue, the maintenance of a free tRNA pool in bacterial systems, the regulation of translation fidelity, and stress response pathways within bacterial systems. Moreover, it also explores the druggability of bacterial Pth, emphasizing its promise as a target for antibacterial agents and highlighting the challenges associated with developing specific inhibitors against this enzyme. Structural elucidation represents a cornerstone in unraveling the catalytic mechanisms and substrate recognition of Pth. This review encapsulates the current structural insights of Pth garnered through various biophysical techniques, such as X-ray crystallography and NMR spectroscopy, providing a detailed understanding of the enzyme's architecture and conformational dynamics. Additionally, biophysical aspects, including its interaction with ligands, inhibitors, and substrates, are discussed, elucidating the molecular basis of bacterial Pth's function and its potential use in drug design strategies. Through this review article, we aim to put together all the available information on bacterial Pth and emphasize its potential in advancing innovative therapeutic interventions and combating bacterial infections.

Synergistic effect of Salvadora persica and chitosan nanoparticles against oropharyngeal microorganisms

Herbal medicine combined with nanoparticles has caught much interest in clinical dental practice, yet the incorporation of chitosan with Salvadora persica (S. persica) extract as an oral care product has not been explored. The aim of this study was to evaluate the combined effectiveness of Salvadora persica(S. persica) and Chitosan nanoparticles (ChNPs) against oropharyngeal microorganisms. Agar well diffusion, minimum inhibitory concentration, and minimal lethal concentration assays were used to assess the antimicrobial activity of different concentrations of ethanolic extracts of S. persica and ChNPs against selected fungal strains, Gram-positive, and Gram-negative bacteria. A mixture of 10% S. persica and 0.5% ChNPs was prepared (SChNPs) and its synergistic effect against the tested microbes was evaluated. Furthermore, the strain that was considered most sensitive was subjected to a 24-h treatment with SChNPs mixture; and examined using SEM, FT-IR and GC-MS analysis. S. persica extract and ChNPs exhibited concentration-dependent antimicrobial activities against all tested strains. S. persica extract and ChNPs at 10% were most effective against S. pneumoni, K. pneumoni, and C. albicans. SEM images confirmed the synergistic effect of the SChNPs mixture, revealing S. pneumonia cells with increased irregularity and higher cell lysis compared to the individual solutions. GC-MS and FT-IR analysis of SChNPs showed many active antimicrobial phytocompounds and some additional peaks, respectively. The synergy of the mixture of SChNPs in the form of mouth-rinsing solutions can be a promising approach for the control of oropharyngeal microbes that are implicated in viral secondary bacterial infections.

Double synergic chitosan-coated poly (lactic-co-glycolic) acid nanospheres loaded with nucleic acids as an intranasally administered vaccine delivery system to control the infection of foot-and-mouth disease virus

BACKGROUND & AIMS

The spread of foot-and-mouth disease virus (FMDV) through aerosol droplets among cloven-hoofed ungulates in close contact is a major obstacle for successful animal husbandry. Therefore, the development of suitable mucosal vaccines, especially nasal vaccines, to block the virus at the initial site of infection is crucial.

PATIENTS AND METHODS

Here, we constructed eukaryotic expression plasmids containing the T and B-cell epitopes (pTB) of FMDV in tandem with the molecular mucosal adjuvant Fms-like tyrosine kinase receptor 3 ligand (Flt3 ligand, FL) (pTB-FL). Then, the constructed plasmid was electrostatically attached to mannose-modified chitosan-coated poly(lactic-co-glycolic) acid (PLGA) nanospheres (MCS-PLGA-NPs) to obtain an active nasal vaccine targeting the mannose-receptor on the surface of antigen-presenting cells (APCs).

RESULTS

The MCS-PLGA-NPs loaded with pTB-FL not only induced a local mucosal immune response, but also induced a systemic immune response in mice. More importantly, the nasal vaccine afforded an 80% protection rate against a highly virulent FMDV strain (AF72) when it was subcutaneously injected into the soles of the feet of guinea pigs.

CONCLUSIONS

The nasal vaccine prepared in this study can effectively induce a cross-protective immune response against the challenge with FMDV of same serotype in animals and is promising as a potential FMDV vaccine.

Chemo-photothermal therapy of chitosan/gold nanorod clusters for antibacterial treatment against the infection of planktonic and biofilm MRSA

Bacterial infections trigger inflammation and impede the closure of skin wounds. The misuse of antibiotics exacerbates skin infections by generating multidrug-resistant bacteria. In this study, we developed chemo-photothermal therapy (chemo-PTT) based on near-infrared (NIR)-irradiated chitosan/gold nanorod (GNR) clusters as anti-methicillin-resistant Staphylococcus aureus (MRSA) agents. The nanocomposites exhibited an average size of 223 nm with a surface charge of 36 mV. These plasmonic nanocomposites demonstrated on-demand and rapid hyperthermal action under NIR. The combined effect of positive charge and PTT by NIR-irradiated nanocomposites resulted in a remarkable inhibition rate of 96 % against planktonic MRSA, indicating a synergistic activity compared to chitosan nanoparticles or GNR alone. The nanocomposites easily penetrated the biofilm matrix. The combination of chemical and photothermal treatments by NIR-stimulated clusters significantly damaged the biofilm structure, eradicating MRSA inside the biomass. NIR-irradiated chitosan/GNR clusters increased the skin temperature of mice by 13 °C. The plasmonic nanocomposites induced negligible skin irritation in vivo. In summary, this novel nanosystem demonstrated potent antibacterial effects against planktonic and biofilm MRSA, showcasing the possible efficacy in treating skin infections.

Revolutionizing eye care: the game-changing applications of nano-antioxidants in ophthalmology

Since the theory of free radical-induced aging was proposed in 1956, it has been constantly proven that reactive oxygen species (ROS) produced by oxidative stress play a vital role in the occurrence and progression of eye diseases. However, the inherent limitations of traditional drug therapy hindered the development of ophthalmic disease treatment. In recent years, great achievements have been made in the research of nanomedicine, which promotes the rapid development of safe theranostics in ophthalmology. In this review, we focus on the applications of antioxidant nanomedicine in the treatment of ophthalmology. The eye diseases were mainly classified into two categories: ocular surface diseases and posterior eye diseases. In each part, we first introduced the pathology of specific diseases about oxidative stress, and then presented the representative application examples of nano-antioxidants in eye disease therapy. Meanwhile, the nanocarriers that were used, the mechanism of function, and the therapeutic effect were also presented. Finally, we summarized the latest research progress and limitations of antioxidant nanomedicine for eye disease treatment and put forward the prospects of future development.

Application of Nanomaterials in Endodontics

Recent advancements in nanotechnology have introduced a myriad of potential applications in dentistry, with nanomaterials playing an increasing role in endodontics. These nanomaterials exhibit distinctive mechanical and chemical properties, rendering them suitable for various dental applications in endodontics, including obturating materials, sealers, retro-filling agents, and root-repair materials. Certain nanomaterials demonstrate versatile functionalities in endodontics, such as antimicrobial properties that bolster the eradication of bacteria within root canals during endodontic procedures. Moreover, they offer promise in drug delivery, facilitating targeted and controlled release of therapeutic agents to enhance tissue regeneration and repair, which can be used for endodontic tissue repair or regeneration. This review outlines the diverse applications of nanomaterials in endodontics, encompassing endodontic medicaments, irrigants, obturating materials, sealers, retro-filling agents, root-repair materials, as well as pulpal repair and regeneration. The integration of nanomaterials into endodontics stands poised to revolutionize treatment methodologies, presenting substantial potential advancements in the field. Our review aims to provide guidance for the effective translation of nanotechnologies into endodontic practice, serving as an invaluable resource for researchers, clinicians, and professionals in the fields of materials science and dentistry.

Multifunctional fucoidan-loaded Zn-MOF-encapsulated microneedles for MRSA-infected wound healing

Infected wound healing remains a challenging task in clinical practice due to several factors: (I) drug-resistant infections caused by various pathogens, (II) persistent inflammation that hinders tissue regeneration and (III) the ability of pathogens to persist intracellularly and evade antibiotic treatment. Microneedle patches (MNs), recognized for their effecacious and painless subcutaneous drug delivery, could greatly enhance wound healing if integrated with antibacterial functionality and tissue regenerative potential. A multifunctional agent with subcellular targeting capability and contained novel antibacterial components, upon loading onto MNs, could yield excellent therapeutic effects on wound infections. In this study, we sythesised a zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) loaded with low molecular weight fucoidan (Fu) and further coating by hyaluronic acid (HA), obtained a multifunctional HAZ@Fu NPs, which could hinders Methicillin-resistant Staphylococcus aureus (MRSA) growth and promotes M2 polarization in macrophages. We mixed HAZ@Fu NPs with photocrosslinked gelatin methacryloyl (GelMA) and loaded it into the tips of the MNs (HAZ@Fu MNs), administered to mice model with MRSA-infected full-thickness cutaneous wounds. MNs are able to penetrate the skin barrier, delivering HAZ@Fu NPs into the dermal layer. Since cells within infected tissues extensively express the HA receptor CD44, we also confirmed the HA endows the nanoparticles with the ability to target MRSA in subcellular level. In vitro and in vivo murine studies have demonstrated that MNs are capable of delivering HAZ@Fu NPs deep into the dermal layers. And facilitated by the HA coating, HAZ@Fu NPs could target MRSA surviving at the subcellular level. The effective components, such as zinc ions, Fu, and hyaluronic acid could sustainably released, which contributes to antibacterial activity, mitigates inflammation, promotes epithelial regeneration and fosters neovascularization. Through the RNA sequencing of macrophages post co-culture with HAZ@Fu, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis reveals that the biological functionalities associated with wound healing could potentially be facilitated through the PI3K-Akt pathway. The results indicate that the synergistic application of HAZ@Fu NPs with biodegradable MNs may serve as a significant adjunct in the treatment of infected wounds. The intricate mechanisms driving its biological effects merit further investigation.

Multifunctional Regeneration Silicon-Loaded Chitosan Hydrogels for MRSA-Infected Diabetic Wound Healing

Repeated microbial infection, excess reactive oxygen species (ROS) accumulation, cell dysfunction, and impaired angiogenesis under hyperglycemia severely inhibit diabetic wound healing. Therefore, developing multifunctional wound dressings accommodating the complex microenvironment of diabetic wounds is of great significance. Here, a multifunctional hydrogel (Regesi-CS) is prepared by loading regeneration silicon (Regesi) in the non-crosslinked chitosan (CS) solution, followed by freeze-drying and hydration. As expected, the blank non-crosslinked CS hydrogel (1%) shows great antibacterial activity against Escherichia coli, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA), improves fibroblast migration, and scavenges intracellular ROS. Interestingly, after loading 1% Regesi, the Regesi-CS (1%-1%) hydrogel shows greater antibacterial activity, significantly promotes fibroblasts proliferation and migration, scavenges much more ROS, and substantially protects fibroblasts under oxidative stress, yet Regesi alone has no or even negative effects. In the MRSA-infected diabetic wound model, Regesi-CS (1%-1%) hydrogel effectively promotes wound healing by eliminating bacterial infection, enhancing granulation tissue formation, promoting collagen deposition, and improving angiogenesis. In conclusion, Regesi-CS hydrogel may be a potential wound dressing for the effective treatment and management of chronic diabetic wounds.

Shelf-life extension of Pacific white shrimp (Litopenaeus vannamei) using sodium alginate/chitosan incorporated with cell-free supernatant of Streptococcus thermophilus FUA 329 during cold storage

Seafood is highly perishable and has a short shelf-life. This study investigated the effect of chitosan and alginate (CH-SA) coating combined with the cell-free supernatant of Streptococcus thermophilus FUA329 (CFS) as a preservative on the quailty of white shrimp (Litopenaeus vannamei) refrigerated at 4° for 0, 3, 6, 9, 12, 15 days. Freshly shrimps were randomly divided into four groups: the CFS group (400 mL); the CH-SA group (1% chitosan/1% alginate); the CFS-CH-SA group (1% chitosan/1% alginate with 400 mL CFS) are treatment groups, and the control group (400 mL sterile water). The CFS-CH-SA coating effectively suppressed microbial growth total viable count and chemical accumulation (pH, total volatile basic nitrogen, thiobarbituric acid reactive substance) compared with the control. Additionally, the CFS-CH-SA coating improved the texture and sensory characteristics of shrimp during storage. The coated shrimp exhibited significantly reduced water loss (p < 0.05). The combination of CH-SA coating with CFS treatment can extend the shelf life of shrimp. PRACTICAL APPLICATION: Recently, edible films have received more consideration as a promising method to enhance the shelf life of seafood. The presence of Lactic acid bacteria metabolites in edible films reduces spoilage and improves consumer health. Our findings encourage the application of edible coating incorporated with cell-free supernatant of Streptococcus thermophilus FUA 329 to design multifubctional foods and preserve the qualities of shrimp.

Preparation and characterization of nisin-loaded chitosan nanoparticles functionalized with DNase I for the removal of Listeria monocytogenes biofilms

Listeria monocytogenes biofilms represent a continuous source of contamination, leading to serious food safety concerns and economic losses. This study aims to develop novel nisin-loaded chitosan nanoparticles (CSNPs) functionalized with DNase I and evaluate its antibiofilm activity against L. monocytogenes on food contact surfaces. Nisin-loaded CSNPs (CS-N) were first prepared by ionic cross-linking, and DNase I was covalently grafted on the surface (DNase-CS-N). The NPs were subsequently characterized by Zetasizer Nano, transmission electron microscopy, Fourier transform infrared (FT-IR), and X-ray diffraction (XRD). The antibiofilm activity of NPs was evaluated against L. monocytogenes on polyurethane (PU). The DNase-CS-N was fabricated and characterized with quality attributes (particle size-427.0 ± 15.1 nm, polydispersity [PDI]-0.114 ± 0.034, zeta potential-+52.5 ± 0.2 mV, encapsulation efficiency-46.5% ± 3.6%, DNase conjugate rate-70.4% ± 0.2). FT-IR and XRD verified the loading of nisin and binding of DNase I with chitosan. The DNase-CS-N caused a 3 log colony-forming unit (CFU)/cm2 reduction of L. monocytogenes biofilm cells, significantly higher than those in CSNPs (1.4 log), CS-N (1.8 log), and CS-N in combination with DNase I (2.2 log) treatment groups. In conclusion, nisin-loaded CSNPs functionalized with DNase I were successfully prepared and characterized with smooth surface and nearly spherical shape, high surface positive charge, and good stability, which is effective to eradicate L. monocytogenes biofilm cells on food contact surfaces, exhibiting great potential as antibiofilm agents in food industry. PRACTICAL APPLICATION: Listeria monocytogenes biofilms are a common safety hazard in food processing. In this study, novel nanoparticles were successfully constructed and are expected to be a promising antibiofilm agent in the food industry.

Aspirin/amoxicillin loaded chitosan microparticles and polydopamine modified titanium implants to combat infections and promote osteogenesis

It is known that titanium (Ti) implant surfaces exhibit poor antibacterial properties and osteogenesis. In this study, chitosan particles loaded with aspirin, amoxicillin or aspirin + amoxicillin were synthesized and coated onto implant surfaces. In addition to analysing the surface characteristics of the modified Ti surfaces, the effects of the modified Ti surfaces on the adhesion and viability of rat bone marrow-derived stem cells (rBMSCs) were evaluated. The metabolic activities of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) biofilms on the modified Ti surfaces were also measured in vitro. Moreover, S. aureus was tested for its antibacterial effect by coating it in vivo. Using water as the droplet medium, the contact angles of the modified Ti surfaces increased from 44.12 ± 1.75° to 58.37 ± 4.15°. In comparison to those of the other groups tested, significant increases in rBMSC adhesion and proliferation were observed in the presence of aspirin + amoxicillin-loaded microspheres, whereas a significant reduction in the metabolic level of biofilms was observed in the presence of aspirin + amoxicillin-loaded microspheres both in vitro and in vivo. Aspirin and amoxicillin could be used in combination to coat implant surfaces to mitigate bacterial activities and promote osteogenesis.

Electrospun Chitosan-Based Nanofibrous Coating for the Local and Sustained Release of Vancomycin

As the population ages, the number of vascular surgery procedures performed increases. Older adults often have multiple comorbidities, such as diabetes and hypertension, that increase the risk of complications from vascular surgery including vascular graft infection (VGI). VGI is a serious complication with significant morbidity, mortality, and healthcare costs. Here, we aimed to develop a nanofibrous chitosan-based coating for vascular grafts loaded with different concentrations of the vancomycin antibiotic vancomycin (VAN). Blending chitosan with poly(vinyl alcohol) or poly(ethylene oxide) copolymers improved solubility and ease of spinning. Thermal gravimetric analysis and Fourier transform infrared spectroscopy confirmed the presence of VAN in the nanofibrous membranes. Kinetics of VAN release from the nanofibrous mats were evaluated using high-performance liquid chromatography, showing a burst followed by sustained release over 24 h. To achieve longer sustained release, a poly(lactic-co-glycolic acid) coating was applied, resulting in extended release of up to 7 days. Biocompatibility assessment using human umbilical vein endothelial cells demonstrated successful attachment and viability of the nanofiber patches. Our study provides insights into the development of a drug delivery system for vascular grafts aimed at preventing infection during implantation, highlighting the potential of electrospinning as a promising technique in the field of vascular surgery.

Strategies to Promote the Journey of Nanoparticles Against Biofilm-Associated Infections

Biofilm-associated infections are one of the most challenging healthcare threats for humans, accounting for 80% of bacterial infections, leading to persistent and chronic infections. The conventional antibiotics still face their dilemma of poor therapeutic effects due to the high tolerance and resistance led by bacterial biofilm barriers. Nanotechnology-based antimicrobials, nanoparticles (NPs), are paid attention extensively and considered as promising alternative. This review focuses on the whole journey of NPs against biofilm-associated infections, and to clarify it clearly, the journey is divided into four processes in sequence as 1) Targeting biofilms, 2) Penetrating biofilm barrier, 3) Attaching to bacterial cells, and 4) Translocating through bacterial cell envelope. Through outlining the compositions and properties of biofilms and bacteria cells, recent advances and present the strategies of each process are comprehensively discussed to combat biofilm-associated infections, as well as the combined strategies against these infections with drug resistance, aiming to guide the rational design and facilitate wide application of NPs in biofilm-associated infections.

Development of anti-bacterial adhesion and antibacterial sulfobetaines modified chitosan/polyvinyl alcohol composite films as packaging materials

Chitosan exhibits a wide source, non-toxic and biodegradable, and is the optimal functional raw material for preparing food packaging materials. However, the pure chitosan film has some disadvantages such as limited antibacterial activity and weak mechanical properties. In this study, sulfobetaines modified chitosan (CS-SBMA) was synthesized by grafting copolymerized betaine methacrylate sulfonate onto the chain of chitosan to improve the anti-bacterial adhesion and antibacterial properties of chitosan, aiming to develop antibacterial and anti-bacterial adhesion films based on CS-SBMA and polyvinyl alcohol (PVA) by the casting method. The structure of CS-SBMA was characterized by 1H NMR and FTIR. The appropriate proportion of CS-SBMA/PVA was determined to be 1/1 and 1/2, by characterizing the composite films with FTIR, XRD, SEM, mechanical, optical, and water resistance behaviors. In addition, CS-SBMA/PVA films showed excellent antibacterial, anti-bacterial adhesion and biofilm control function. The colonies number of E. coli and S. aureus on the surface of CS-SBMA/PVA 1/1 film decreased 94.15 % and 94.27 %, respectively, and 92.93 % of S. aureus and 94.87 % of E. coli colonies were inactivated within 60 min contact. These results indicate that CS-SBMA/PVA film exhibits potential antibacterial and anti-bacterial adhesion properties, which is suitable for food packaging materials.

Strategies for the eradication of intracellular bacterial pathogens

Intracellular pathogens affect a significant portion of world population and cause millions of deaths each year. They can invade host cells and survive inside them and are extremely resistant to immune systems and antibiotics. Current treatments have limitations, and therefore, new effective therapies are needed to combat this ongoing health challenge. Active research efforts have been made to develop many new strategies to eradicate these intracellular pathogens. In this review, we focus on the intracellular bacterial pathogens and first introduce several representative intracellular bacteria and the diseases they cause. We then discuss the challenges in eradicating these bacteria and summarize the current therapeutics for intracellular bacteria. Finally, recent advances in intracellular bacteria eradication are highlighted.

An Overview of Polymeric Nanoplatforms to Deliver Veterinary Antimicrobials

There is an urgent need to find new solutions for the global dilemma of increasing antibiotic resistance in humans and animals. Modifying the performance of existing antibiotics using the nanocarrier drug delivery system (DDS) is a good option considering economic costs, labor costs, and time investment compared to the development of new antibiotics. Numerous studies on nanomedicine carriers that can be used for humans are available in the literature, but relatively few studies have been reported specifically for veterinary pharmaceutical products. Polymer-based nano-DDS are becoming a research hotspot in the pharmaceutical industry owing to their advantages, such as stability and modifiability. This review presents current research progress on polymer-based nanodelivery systems for veterinary antimicrobial drugs, focusing on the role of polymeric materials in enhancing drug performance. The use of polymer-based nanoformulations improves treatment compliance in livestock and companion animals, thereby reducing the workload of managers. Although promising advances have been made, many obstacles remain to be addressed before nanoformulations can be used in a clinical setting. Some crucial issues currently facing this field, including toxicity, quality control, and mass production, are discussed in this review. With the continuous optimization of nanotechnology, polymer-based DDS has shown its potential in reducing antibiotic resistance to veterinary medicines.

In situ, synthesis of chitosan fabricated tellurium nanoparticles for improved antimicrobial and anticancer applications

The emergence of antibiotic resistance has had a severe impact on human health and economic burdens, drawing attention to the development of novel antimicrobial therapies. Polymer-metal composites have shown evidence of therapeutic applications by exerting antimicrobial effects and delivering these antimicrobials with biocompatibility. Therefore, this study prepared and characterized chitosan (CS)-fabricated tellurium nanoparticles (Te NPs) for enhanced antimicrobial, antioxidant, and cytotoxicity applications. The CS-Te NPs were spherical, polydisperse, and distributed within the CS matrix with an average size of 37.48 ± 14.56 nm, as confirmed by TEM analysis. CS-Te NPs exhibited positive zeta potential in neutral (pH 7.0: 7.90 ± 1.86 mV) and acidic environment. XRD analysis confirmed the crystalline nature of CS-Te NPs, and these nanoparticles exhibited good thermal and less porosity. A higher release of Te ions occurred from CS-Te NPs at an acidic pH. Further, CS-Te NPs displayed stronger antibacterial and antibiofilm activity against E. coli and S. enterica. Furthermore, CS-Te NPs exhibited significant free radical scavenging activity against ABTS and DPPH free radicals. Moreover, these nanoparticles demonstrated cytotoxicity against cancerous cells (A549 and PC3 cells) when compared to normal cells (NIH3T3 cells). Therefore, this study suggests that CS-Te NPs could serve as a substantial therapeutic agent.

Bio-inspired copper ion-chelated chitosan coating modified UHMWPE fibers for enhanced interfacial properties of composites

Ultra-high molecular weight polyethylene (UHMWPE) fibers are broadly applied in lightweight and high-strength composite fiber materials. However, the development of UHMWPE fibers is limited by their smooth and chemically inert surfaces. To address the issues, a modified UHMWPE fibers material has been fabricated through the chelation reaction between Cu2+ and chitosan coatings within the surface of fibers after plasma treatment, which is inspired by the hardening mechanism, a crosslinked network between metal ions and proteins/polysaccharides of the tips and edges in arthropod-specific cuticular tools. The coatings improve the surface wettability and interfacial bonding ability, which are beneficial in extending the application range of UHMWPE fibers. More importantly, compared to the unmodified UHMWPE fiber cloths, the tensile property of the modified fiber cloths is increased by 18.89% without damaging the strength, which is infrequent in modified UHMWPE fibers. Furthermore, the interlaminar shear strength and fracture toughness of the modified fibers laminate are increased by 37.72% and 135.90%, respectively. These improvements can be attributed to the synergistic effects between the surface activity and the tiny bumps of the modified UHMWPE fibers. Hence, this work provides a more straightforward and less damaging idea of fiber modification for manufacturing desirable protective and medical materials.

Recent Advances in Nanotechnology-Based Strategies for Bone Tuberculosis Management

Bone tuberculosis, an extrapulmonary manifestation of tuberculosis, presents unique treatment challenges, including its insidious onset and complex pathology. While advancements in anti-tubercular therapy have been made, the efficacy is often limited by difficulties in achieving targeted drug concentrations and avoiding systemic toxicity. The intricate bone structure and presence of granulomas further impede effective drug delivery. Nano-drug delivery systems have emerged as a promising alternative, offering the enhanced targeting of anti-tubercular drugs. These systems, characterized by their minute size and adaptable surface properties, can be tailored to improve drug solubility, stability, and bioavailability, while also responding to specific stimuli within the bone TB microenvironment for controlled drug release. Nano-drug delivery systems can encapsulate drugs for precise delivery to the infection site. A significant innovation is their integration with prosthetics or biomaterials, which aids in both drug delivery and bone reconstruction, addressing the infection and its osteological consequences. This review provides a comprehensive overview of the pathophysiology of bone tuberculosis and its current treatments, emphasizing their limitations. It then delves into the advancements in nano-drug delivery systems, discussing their design, functionality, and role in bone TB therapy. The review assesses their potential in preclinical research, particularly in targeted drug delivery, treatment efficacy, and a reduction of side effects. Finally, it highlights the transformative promise of nanotechnology in bone TB treatments and suggests future research directions in this evolving field.