Development and optimization of pH-responsive PLGA-chitosan nanoparticles for triggered release of antimicrobials

Doxycycline-Loaded pH-Sensitive Microparticles as a Potential Site-Specific Drug Delivery System against Periodontitis

A significant obstacle to the healing process of periodontitis is the development of bacterial biofilms within the periodontal pockets. The efficacy of bacterial biofilm therapy is often hindered by the inadequate penetration of antibacterial agents and the nonspecific targeting of bacteria. This study proposes a novel strategy involving the utilization of pH-sensitive microparticles (MPs) of doxycycline (DOX) to enhance biofilm penetration and enable targeted delivery of DOX to infection sites associated with periodontitis. The MPs were developed using a double-emulsion technique with poly(d,l-lactide-co-glycolide) and chitosan in a 1:1 ratio. The morphology of DOX-MP exhibits a spherical form with a particle size of 3.54 ± 0.32 μm and a PDI of 0.221 ± 0.02. The DOX-MP also had great encapsulation efficiency (69.43% ± 5.32) and drug loading efficiency (14.81% ± 1.32) with regulated drug release kinetics and accelerated release rates under low-pH conditions. The antimicrobial activity was evaluated against Escherichia coli and Staphylococcus aureus, and the results indicated the absence of any viable bacterial colonies after 18 h at twice the minimum inhibitory concentration value. Hydrogel-based MPs deliver DOX to the periodontal pocket infection site for ease of use. In situ hydrogels used Pluronic F127 and F68 as the main polymer composition and hydroxypropyl methylcellulose as the adhesion polymer. This formulation exhibited a liquid state at room temperature (25 °C) but went through gelation at 36 °C. The formulation also had good mucoadhesive characteristics (42.65 ± 3.53 dyn/cm2) and good drug permeation at acidic pH in Mueller-Hinton Broth media with the addition of E. coli and S. aureus bacteria. Ex vivo antibacterial activity significantly reduced the microbial count, biofilm quantity, and metabolic activity, confirming the desired antibacterial effect. Hence, the utilization of free drugs and DOX-MPs did not exhibit a notable dissimilarity, showing that integrating the drug into the matrix was not hindering its antibacterial efficacy.

Dexamethasone-loaded chitosan-decorated PLGA nanoparticles: A step forward in attenuating the COVID-19 cytokine storm?

This study aims to develop and characterize poly (lactic-co-glycolic acid) (PLGA) nanoparticles decorated with chitosan (CS) for the encapsulation of dexamethasone (DEX) (NP-DEX-CS), targeting improved efficacy in the treatment of severe acute respiratory syndrome (SARS) associated with COVID-19. The nanoparticles were systematically characterized for size, zeta potential (ZP), morphology, encapsulation efficiency, and in vitro drug release. Incorporation of CS resulted in significant modifications in the nanoparticles' physical properties, notably an increase in size (from 207.3 ± 6.7 nm to 264.4 ± 4.4 nm) and a shift in ZP to positive values (from -11.8 ±1.4 mV to +30.0 ± 1,6 mV). The NP-DEX-CS formulation achieved a high encapsulation efficiency (∼79 %) and a drug loading capacity of 6.53 ± 0.02 %.In addition, the in vitro release rate of DEX from NP-DEX-CS was lower compared to undecorated nanoparticles, with a reduction from approximately 64-37 % within 24 h. Microscopy analyses revealed a smoother surface on the CS-decorated nanoparticles. FTIR and XRD analyses confirmed successful chitosan coating and DEX encapsulation. The CS coating enhanced the tolerability of J774.A1 cells to the nanoparticles, particularly evident at the highest concentration (400ug/mL), resulting in a cell viability ≥70 %. Importantly, the NP-DEX-CS significantly reduced levels of nitric oxide and inflammatory cytokines (IL-1, IL-6, IL-12, and TNF-α). These findings suggest that CS-decorated PLGA nanoparticles hold promise as an effective dexamethasone delivery system for treating SARS related to COVID-19.

Nanotechnology Meets Phytotherapy: A Cutting-Edge Approach to Treat Bacterial Infections

The increasing prevalence of bacterial infections and the rise in antibiotic resistance have prompted the search for alternative therapeutic strategies. One promising approach involves combining plant-based bioactive substances with nanoparticles, which have demonstrated improved antimicrobial activity compared to their free forms, both in vitro, in vivo, and in clinical studies. This approach not only improves their stability but also enables targeted delivery to bacterial cells, reducing side effects and minimising the risk of resistance development, leading to more effective treatments. This narrative review explores the benefits of combining bioactive plant compounds (berberine, catechin, chelerythrine, cinnamaldehyde, ellagic acid, proanthocyanidin, and sanguinarine) with nanoparticles for the treatment of bacterial infections (caused by Staphylococcus aureus, Enterococcus spp., Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, Serratia marcescens, and Pseudomonas aeruginosa), highlighting the potential of this approach to overcome the limitations of traditional antimicrobial therapies. Ultimately, this strategy offers a promising alternative in the fight against resistant bacterial strains, paving the way for the development of more effective and sustainable treatments.

Bovine serum albumin as a nanocarrier for efficient encapsulation of hydrophobic garcinol-A strategy for modifying the in vitro drug release kinetics

Garcinia indica, known as kokum, has been extensively researched for its therapeutic potential. Among the wide variety of phytoconstituents, garcinol is the most efficacious, holding anti-inflammatory, anti-cancer, and anti-diabetic properties. Hydrophobicity and a certain level of toxicity have constrained the drug's application and necessitated a modified dosage form design. The drug has been well explored in the form of extracts but bears very limited application in dosage forms. These prompted in implementation of protein polymers, due to non-toxicity, biocompatibility, and biodegradability. BSA encapsulates the drug, by the desolvation method. The unavailability of past exploration of garcinol with protein polymer accelerated the novelty of this study, to improve the solubility and bioavailability of the drug, modify the drug release kinetics, and ascertain the effectiveness of the NPs to combat inflammation in-vitro. NPs were characterized and satisfactory outcomes were retrieved in terms of all characterizations. The drug release studies depicted a sustained release of up to 85 % over 16 h, ensuring that garcinol can be modulated to give a desired scale of modified release. In vitro cellular uptake studies suggested a substantial uptake of NPs in cell lines and its effectiveness to mitigate inflammation was affirmed by in-vitro anti-inflammatory studies, using ELISA.

Preparation, characterization and evaluation of microwave-assisted synthesized selenylation Codonopsis pilosula polysaccharides

In this work, the selenylation Codonopsis pilosula polysaccharide (Se-CPPS) were synthesized using an optimized microwave-assisted method. Then, physicochemical properties, including molecular weight, particle size, valence state of selenium, antioxidant capacity, release mechanism of selenium under gastrointestinal conditions, as well as their effects on HT-29 cell viability were comprehensively investigated. The results demonstrated that Se-CPPS with the highest selenium content (21.71 mg/g) was synthesized using 0.8% nitric acid concentration under microwave conditions of 90 min at 70 °C. FTIR and XPS analysis revealed that Se was bound to the polysaccharide chain in the form of O-Se-O and O-H···Se, with a valence state of either 0 or +4. In vitro investigations on antioxidant activity and selenium release capacity indicated that selenization not only enhanced the antioxidant activity of CPPS but also endowed Se-CPPS with robust selenium release capability in simulated gastric digestion. The effects of Se-CPPS on HT-29 cells was further investigated by CCK-8 method. The results showed that the selenide modification effectively reduced the toxicity of Na2SeO3 and enhanced the viability of CPPS. The findings of this study offer valuable methodological guidance for the synthesis of Se-polysaccharides with superior functional properties.

Application of PLGA in Tumor Immunotherapy

Biodegradable polymers have been extensively researched in the field of biomedicine. Polylactic-co-glycolic acid (PLGA), a biodegradable polymer material, has been widely used in drug delivery systems and has shown great potential in various medical fields, including vaccines, tissue engineering such as bone regeneration and wound healing, and 3D printing. Cancer, a group of diseases with high mortality rates worldwide, has recently garnered significant attention in the field of immune therapy research. In recent years, there has been growing interest in the delivery function of PLGA in tumor immunotherapy. In tumor immunotherapy, PLGA can serve as a carrier to load antigens on its surface, thereby enhancing the immune system's ability to attack tumor cells. Additionally, PLGA can be used to formulate tumor vaccines and immunoadjuvants, thereby enhancing the efficacy of tumor immunotherapy. PLGA nanoparticles (NPs) can also enhance the effectiveness of tumor immunotherapy by regulating the activity and differentiation of immune cells, and by improving the expression and presentation of tumor antigens. Furthermore, due to the diverse physical properties and surface modifications of PLGA, it has a wider range of potential applications in tumor immunotherapy through the loading of various types of drugs or other innovative substances. We aim to highlight the recent advances and challenges of plga in the field of oncology therapy to stimulate further research and development of innovative PLGA-based approaches, and more effective and personalized cancer therapies.

Essential-Oils-Loaded Biopolymeric Nanoparticles as Strategies for Microbial and Biofilm Control: A Current Status

The emergence of bacterial strains displaying resistance to the currently available antibiotics is a critical global concern. These resilient bacteria can form biofilms that play a pivotal role in the failure of bacterial infection treatments as antibiotics struggle to penetrate all biofilm regions. Consequently, eradicating bacteria residing within biofilms becomes considerably more challenging than their planktonic counterparts, leading to persistent and chronic infections. Among various approaches explored, essential oils loaded in nanoparticles based on biopolymers have emerged, promising strategies that enhance bioavailability and biological activities, minimize side effects, and control release through regulated pharmacokinetics. Different available reviews analyze nanosystems and essential oils; however, usually, their main goal is the analysis of their antimicrobial properties, and progress in biofilm combat is rarely discussed, or it is not the primary objective. This review aims to provide a global vision of biofilm conformation and describes mechanisms of action attributed to each EO. Furthermore, we present a comprehensive overview of the latest developments in biopolymeric nanoparticles research, especially in chitosan- and zein-based nanosystems, targeting multidrug-resistant bacteria in both their sessile and biofilm forms, which will help to design precise strategies for combating biofilms.

Overview of Antimicrobial Biodegradable Polyester-Based Formulations

As the clinical complications induced by microbial infections are known to have life-threatening side effects, conventional anti-infective therapy is necessary, but not sufficient to overcome these issues. Some of their limitations are connected to drug-related inefficiency or resistance and pathogen-related adaptive modifications. Therefore, there is an urgent need for advanced antimicrobials and antimicrobial devices. A challenging, yet successful route has been the development of new biostatic or biocide agents and biomaterials by considering the indisputable advantages of biopolymers. Polymers are attractive materials due to their physical and chemical properties, such as compositional and structural versatility, tunable reactivity, solubility and degradability, and mechanical and chemical tunability, together with their intrinsic biocompatibility and bioactivity, thus enabling the fabrication of effective pharmacologically active antimicrobial formulations. Besides representing protective or potentiating carriers for conventional drugs, biopolymers possess an impressive ability for conjugation or functionalization. These aspects are key for avoiding malicious side effects or providing targeted and triggered drug delivery (specific and selective cellular targeting), and generally to define their pharmacological efficacy. Moreover, biopolymers can be processed in different forms (particles, fibers, films, membranes, or scaffolds), which prove excellent candidates for modern anti-infective applications. This review contains an overview of antimicrobial polyester-based formulations, centered around the effect of the dimensionality over the properties of the material and the effect of the production route or post-processing actions.

Optimization and Appraisal of Chitosan-Grafted PLGA Nanoparticles for Boosting Pharmacokinetic and Pharmacodynamic Effect of Duloxetine HCl Using Box-Benkhen Design

Duloxetine HCl (DXH) is a psychiatric medicine employed for treating major depressive disorder. Nonetheless, its low water solubility, high first-pass metabolism, and acid instability diminish the absolute oral bioavailability to 40%, thus necessitating frequent administration. Therefore, the aim of the current study was to formulate DXH as nasal chitosan-grafted polymeric nanoparticles to improve its pharmacokinetic and pharmacodynamic properties. Applying the Box-Behnken design, DXH loaded PLGA-Chitosan nanoparticles (DXH-PLGA-CS-NPs) were fabricated and optimized using polylactide-co-glycolic acid (PLGA), chitosan (CS), and polyvinyl alcohol (PVA) as the independent factors. Particle size, entrapment efficiency, release percent, and cumulative amount permeated after 24 h of DXH-PLGA-CS-NPs (dependent variables) were evaluated. The in-vivo biodistribution and pharmacodynamic studies were done in male Wistar rats. The optimized DXH-PLGA-CS-NPs had a vesicle size of 122.11 nm and EE% of 66.95 with 77.65% release and Q₂₄ of 555.34 (µg/cm²). Ex-vivo permeation study revealed 4-folds increase in DXH permeation from DXH-PLGA-CS-NPs after 24 h compared to DXH solution. Intranasal administration of optimized DXH-PLGA-CS-NPs resulted in significantly higher (p < 0.05) C_max, AUC_total, t_1/2, and MRT in rat brain and plasma than oral DXH solution. Pharmacodynamics investigation revealed that intranasally exploited optimal DXH-PLGA-CS-NPs could be deemed a fruitful horizon for DXH as a treatment for depression.

Research Progress of Bioinspired Nanostructured Systems for the Treatment of Ocular Disorders

How to enhance the bioavailability and prolong the residence time of drugs in the eye present the major barriers to traditional eye delivery. Nanotechnology has been widely used in ocular drug delivery systems because of its advantages of minimizing adverse reactions, decreasing the frequency of administration, prolonging the release time, and improving the bioavailability of the drug in the eye. As natural product-based nanostructured systems, bioinspired nanostructured systems have presented as less toxic, easy to prepare, and cost-effective and have potential application value in the field of nanotechnology. A systematic classification of bioinspired nanostructured systems based on their inspiration source and formulation and their brief applications in disease are presented here. A review of recent research progress of the bioinspired nanostructured systems for the treatment of the anterior and posterior segment of ocular disorders is then presented in detail. Finally, current challenges and future directions with regard to manufacturing bioinspired nanomaterials are provided.

Triborheological Analysis of Reconstituted Gastrointestinal Mucus/Chitosan:TPP Nanoparticles System to Study Mucoadhesion Phenomenon under Different pH Conditions

Polymeric nanoparticles have attracted much attention as pharmaceutical delivery vehicles to prolong residence time and enhance the bioavailability of therapeutic molecules through the mucoadhesive phenomenon. In this study, chitosan:TPP nanoparticles were synthetized using the ionic gelation technique to analyze their mucoadhesive interaction with reconstituted porcine gastrointestinal mucus from a triborheological point of view under different pH conditions (pH = 2.0, 4.0, 6.0 and 7.0). The triborheological profile of the reconstituted mucus was evaluated at different pH environments through the oscillation frequency and the flow sweep tests, demonstrating that the reconstituted mucus exhibits shear thinning behavior regardless of pH, while its viscoelastic properties showed a change in behavior from a polymeric solution performance under neutral pH conditions to a viscoelastic gel under acidic conditions. Additionally, a rheological synergism analysis was performed to visualize the changes that occur in the viscoelastic properties, the viscosity and the coefficient of friction of the reconstituted mucus samples as a consequence of the interaction with the chitosan:TPP nanoparticles to determine or to discard the presence of the mucoadhesion phenomenon under the different pH values. Mucoadhesiveness evaluation revealed that chitosan:TPP exhibited strong mucoadhesion under highly acidic pH conditions, below its pKa value of 6.5. In contrast, at neutral conditions or close to its pKa value, the chitosan:TPP nanoparticles' mucoadhesiveness was negligible.

Tissue-engineered bones with adipose-derived stem cells - composite polymer for repair of bone defects

Background: Development of alternative bone tissue graft materials based on tissue engineering technology has gradually become a research focus. Engineered bone composed of biodegradable, biosafe and bioactive materials is attractive, but also challenging. Materials & methods: An adipose-derived stem cell/poly(L-glutamic acid)/chitosan composite scaffold was further developed for construction of biodegradable and bone-promoting tissue-engineered bone. A series of composite scaffold materials with different physical properties such as structure, pore size, porosity and pore diameter was developed. Results: The composite scaffold showed good biodegradability and water absorption, and exhibited an excellent ability to promote bone differentiation. Conclusion: This type of biodegradable scaffold is expected to be applied to the field of bone repair or bone tissue engineering.

Stimuli-responsive nanoplatforms for antibacterial applications

The continuously increasing bacterial resistance has become a big threat to public health worldwide, which makes it urgent to develop innovative antibacterial strategies. Nanotechnology-based drug delivery systems are considered as promising strategies in combating bacterial infections which are expected to improve the therapeutic efficacy and minimize the side effects. Unfortunately, the conventional nanodrug delivery systems always suffer from practical dilemmas, including incomplete and slow drug release, insufficient accumulation in infected sites, and weak biofilm penetration ability. Stimuli-responsive nanoplatforms are hence developed to overcome the disadvantages of conventional nanoparticles. In this review, we provide an extensive review of the recent progress of endogenous and exogenous stimuli-responsive nanoplatforms in the antibacterial area, including planktonic bacteria, intracellular bacteria, and bacterial biofilms. Taking advantage of the specific infected microenvironment (pH, enzyme, redox, and toxin), the mechanisms and strategies of the design of endogenous stimuli-responsive nanoplatforms are discussed, with an emphasis on how to improve the therapeutic efficacy and minimize side effects. How to realize controlled drug delivery using exogenous stimuli-responsive nanoplatforms especially light-responsive nanoparticles for improved antibacterial effects is another topic of this review. We especially highlight photothermal-triggered drug delivery systems by the combination of photothermal agents and thermo-responsive materials. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Self-Assembly of Soluplus in Aqueous Solutions: Characterization and Prospectives on Perfume Encapsulation

Soluplus is an amphiphilic graft copolymer intensively studied as a micellar solubilizer for drugs. An extensive characterization of the nanostructure of its colloidal aggregates is still lacking. Here, we provide insights into the polymer's self-assembly in water, and we assess its use as an encapsulating agent for fragrances. The self-assembly properties of Soluplus aqueous solutions were studied over a wide concentration range (1-70% w/w) by means of small-angle neutron scattering (SANS), differential scanning calorimetry, NMR, and rheometry. SANS analyses revealed the presence of polymeric micelles with a fuzzy surface interacting via a 2-Yukawa potential, up to 15% w/w polymer. Increasing the polymer concentration up to 55% w/w led to tightly packed micelles described according to the Teubner-Strey model. The ability of Soluplus to encapsulate seven perfume molecules, 2-phenyl ethanol, l-carvone, linalool, florhydral, β-citronellol, α-pinene, and R-limonene, was then examined. We showed that the fragrance's octanol/water partition coefficient (log K_ow), widely used to characterize the solubilization capacity, is not sufficient to characterize such systems and the presence of specific functional groups or molecular conformation needs to be considered. In fact, the combination of SANS, NMR, confocal laser scanning microscopy, and confocal Raman microscopy showed that the perfumes, interacting with different regions of the polymer aggregates, are able to tune the systems' structures resulting in micelles, matrix-type capsules, core-shell capsules, or oil-in-water emulsions.

Construction and performance of exendin-4-loaded chitosan-PLGA microspheres for enhancing implant osseointegration in type 2 diabetic rats

The updating and optimization of drug delivery systems is critical for better in vivo behaviors of drugs, as well as for improving impaired implant osseointegration in diabetes. Numerous studies have reported the benefits of exendin-4 on diabetic bone, with the potential to enhance osseointegration in diabetes. To construct an appropriate sustained-release system of exendin-4 targeting implant osseointegration in diabetes, this study fabricated exendin-4-loaded microspheres using poly(lactic-co-glycolic acid) (PLGA) and chitosan. The morphology, size, encapsulation efficiency, and drug release behavior of microspheres were investigated. The bioactivity of drug-loaded microspheres on cell proliferation and osteogenic differentiation of diabetic BMSCs was investigated to examine the pharmacologic action of exendin-4 loaded into chitosan-PLGA microspheres. Further, the influence of microspheres on osseointegration was evaluated using type 2 diabetes mellitus (T2DM) rat implant model. After 4 weeks, the samples were evaluated by radiological and histological analysis. The results of in vitro experiments showed that the prepared exendin-4-loaded chitosan-PLGA microspheres have good properties as a drug delivery system, and the chitosan could improve the encapsulation efficiency and drug release of PLGA microspheres. In addition, exendin-4-loaded microspheres could enhance the proliferation and osteogenic differentiation of diabetic BMSCs. The results of in vivo experiments showed the exendin-4-loaded microspheres significantly improved the impaired osseointegration and bone formation around implants in T2DM rats without affecting blood glucose levels. Thus, the local application of exendin-4-loaded chitosan-PLGA microspheres might be a promising therapeutic strategy for improving the efficacy of dental implants in T2DM individuals.

Formulation and characterization of hydroxyethyl cellulose-based gel containing metronidazole-loaded solid lipid nanoparticles for buccal mucosal drug delivery

Local delivery of drug is a promising strategy to manage periodontitis characterized by chronic inflammation of the soft tissue surrounding the teeth. An optimized system should prolong the drug retention time and exhibit controlled drug permeation through the buccal mucosal layer. This study was aimed to develop hydroxyethyl cellulose (HEC)-based gel containing metronidazole (MTZ) loaded in solid lipid nanoparticles (SLNs), and to enhance the antimicrobial activity of MTZ. SLNs were prepared using a combination method of solvent evaporation and hot homogenization. The results showed that the fabricated SLNs, comprising of Precirol (2.93%, w/v), Tween 80 (1.8%, w/v), and the drug:lipid ratio of 19.3% (w/w), were approximately 200 nm in size, with a narrow distribution. The HEC (3%, w/w)-based gel formed a smooth, homogeneous structure and had preferable mechanical and rheological properties. Moreover, the MTZ-loaded SLNs-based HEC gel (equivalent to 1% of MTZ, w/w) exhibited a sustained in vitro drug release pattern, optimal ex vivo permeability, and enhanced in vitro antimicrobial activity after 24 h of treatment. These findings indicate the potential of the MTZ-loaded SLNs-based HEC formulation for local drug delivery at the buccal mucosa in managing periodontal disease.

Encapsulation of volatile compounds in liquid media: Fragrances, flavors, and essential oils in commercial formulations

The first marketed example of the application of microcapsules dates back to 1957. Since then, microencapsulation techniques and knowledge have progressed in a plethora of technological fields, and efforts have been directed toward the design of progressively more efficient carriers. The protection of payloads from the exposure to unfavorable environments indeed grants enhanced efficacy, safety, and stability of encapsulated species while allowing for a fine tuning of their release profile and longer lasting beneficial effects. Perfumes or, more generally, active-loaded microcapsules are nowadays present in a very large number of consumer products. Commercial products currently make use of rigid, stable polymer-based microcapsules with excellent release properties. However, this type of microcapsules does not meet certain sustainability requirements such as biocompatibility and biodegradability: the leaking via wastewater contributes to the alarming phenomenon of microplastic pollution with about 4% of total microplastic in the environment. Therefore, there is a need to address new issues which have been emerging in relation to the poor environmental profile of such materials. The progresses in some of the main application fields of microencapsulation, such as household care, toiletries, cosmetics, food, and pesticides are reviewed herein. The main technologies employed in microcapsules production and the mechanisms underlying the release of actives are also discussed. Both the advantages and disadvantages of every technique have been considered to allow a careful choice of the most suitable technique for a specific target application and prepare the ground for novel ideas and approaches for encapsulation strategies that we expect to be proposed within the next years.

Micelle nanovehicles for co-delivery of Lepidium meyenii Walp. (maca) polysaccharide and chloroquine to tumor-associated macrophages for synergistic cancer immunotherapy

Here, we fabricated amphiphilic polysaccharide micelles for synergistic cancer immunotherapy targeting tumor-associated macrophages (TAMs). Lepidium meyenii Walp. (maca) polysaccharide (MP), a naturally derived macromolecule with a strong TAM-remodeling effect, was grafted on a hydrophobic poly(lactic-co-glycolic acid) (PLGA) segment, with a disulfide bond for redox-sensitive linkage. The amphiphilic polysaccharide derivatives could self-assemble into core (PLGA)-shell (MP)-structured micelles and encapsulate chloroquine (CQ) into the hydrophobic core. By using a 4T1-M2 macrophage co-culture model and a 4T1 tumor xenograft mouse model, we showed that the prepared micelles could co-deliver MP and CQ to the tumor sites and selectively accumulate at TAMs because of the specific properties of MP. Furthermore, the nanoparticles exerted synergistic tumor immunotherapeutic and antimetastatic effects, which might be attributable to the enhanced cell internalization of the micelles and the multiple regulatory mechanisms of MP and CQ. Thus, immunomodulatory MP may be a promising biomaterial for cancer immunotherapy.

Informative and corrective responsive packaging: Advances in farm-to-fork monitoring and remediation of food quality and safety

Microbial growth and fluctuations in environmental conditions have been shown to cause microbial contamination and deterioration of food. Thus, it is paramount to develop reliable strategies to effectively prevent the sale and consumption of contaminated or spoiled food. Responsive packaging systems are designed to react to specific stimuli in the food or environment, such as microorganisms or temperature, then implement an informational or corrective response. Informative responsive packaging is aimed at continuously monitoring the changes in food or environmental conditions and conveys this information to the users in real time. Meanwhile, packaging systems with the capacity to control contamination or deterioration are also of great interest. Encouragingly, corrective responsive packaging attempting to mitigate the adverse effects of condition fluctuations on food has been investigated. This packaging exerts its effects through the triggered release of active agents by environmental stimuli. In this review, informative and corrective responsive packaging is conceptualized clearly and concisely. The mechanism and characteristics of each type of packaging are discussed in depth. This review also summarized the latest research progress of responsive packaging and objectively appraised their advantages. Evidently, the mechanism through which packaging systems respond to microbial contamination and associated environmental factors was also highlighted. Moreover, risk concerns, related legislation, and consumer perspective in the application of responsive packaging are discussed as well. Broadly, this comprehensive review covering the latest information on responsive packaging aims to provide a timely reference for scientific research and offer guidance for presenting their applications in food industry.

Delivery of selenium using chitosan nanoparticles: Synthesis, characterization, and antioxidant and growth effects in Nile tilapia (Orechromis niloticus)

This study aimed to elucidate the effects of selenium-loaded chitosan nanoparticles used as a dietary supplement on Nile tilapia (Oreochromis niloticus) antioxidant and growth responses. First, chitosan-based nanoparticles containing selenium (Se) were synthesized using the ionotropic gelation method and their physicochemical characteristics, controlled release profile, and antioxidant activity properties were investigated. Thereafter, the effects on glutathione peroxidase and antioxidant activities (by radical scavenging activity), growth, and whole-body composition of Nile tilapia were evaluated when they were fed with Se-loaded chitosan nanoparticles and compared with other selenium dietary supplements. Se-loaded chitosan nanoparticles showed high entrapment efficiency (87%), spherical shape, smooth surface, and broad size distribution. The controlled release of Se consisted of an initial burst followed by a gradual release over 48 h. Se-loaded nanoparticles presented significantly higher antioxidant activity compared to free Se. A 60-day feeding trial was conducted to compare the effects of supplementing different dietary Se sources, including selenomethionine (as organic source), sodium selenite (as inorganic source), and Se-loaded chitosan nanoparticles (Se-Nano and Se-Nano x1.5) on antioxidant and growth responses of Nile tilapia. A basal diet without Se supplementation was used as the control. The dietary supplementations with different Se sources (free and encapsulated selenium) lead to significant improvements in final weight and feed efficiency of Nile tilapia fingerlings. However, dietary treatments did not affect whole-body protein and lipid content. Diets containing Se-Nano and Se-Nano x1.5 were more effective than sodium selenite and selenomethionine in preventing oxidative stress and improving antioxidant activity in Nile tilapia. Overall, Se-loaded nanoparticles presented a great potential as an efficient source for delivering dietary Se to Nile tilapia, directly affecting the growth performance, feed efficiency, oxidative stress, and antioxidant activity of this species.

Nanoparticles of Chitosan/Poly(D,L-Lactide-Co-Glycolide) Enhanced the Immune Responses of Haemonchus contortus HCA59 Antigen in Model Mice

Background

Hepatocellular carcinoma-associated antigen 59 (HCA59) from excretory/secretory products of Haemonchus contortus is known to have the ability to modulate the functions of host cells. However, its immunogenicities using different nanoparticles adjuvants remain poorly understood.

Purpose

The study aimed to select an efficient nanoparticle antigen delivery system, which could enhance the immune responses of Haemonchus contortus HCA59 in mice.

Methods

Here, the immune responses induced by the recombinant protein of HCA59 (rHCA59) with poly-D,L-lactide-co-glycolide (PLGA) nanoparticles, Chitosan nanoparticles, mixture of PLGA and Chitosan nanoparticles (rHCA59-Chitosan-PLGA), and Freund’s complete adjuvant were observed, respectively, in mice. Cytokine and antibody levels induced by different groups were detected by ELISA assay. The effects of lymphocyte proliferations on different groups were examined using CCK-8 kit. Phenotypes of T cells and dendritic cells were analyzed by flow cytometry.

Results

On day 14 post vaccination, levels of IgM, IgG1, IgG2a, IFN-γ, IL-4, and IL-17 were significantly increased in the groups immunized with rHCA59 encapsulated with nanoparticles. After mice were vaccinated with rHCA59 loaded with Chitosan/PLGA nanoparticles, lymphocytes proliferated significantly. Additionally, the percentages of CD4⁺ T cells (CD3⁺ CD4⁺), CD8⁺ T cells (CD3⁺ CD8⁺), and dendritic cells (CD11c⁺ CD83⁺, CD11c⁺ CD86⁺) were obviously up-regulated in the mice immunized with nanoparticles, especially in the rHCA59-Chitosan-PLGA antigen delivery system group.

Conclusion

The findings of this research demonstrated that rHCA59-Chitosan-PLGA antigen delivery system could induce higher immune responses in mice model and indicated that rHCA59 might be a good candidate molecule to develop nanovaccines against Haemonchus contortus in future study.

Selenium release kinetics and mechanism from Cordyceps sinensis exopolysaccharide-selenium composite nanoparticles in simulated gastrointestinal conditions

This work investigated selenium (Se) release kinetics and mechanism from exopolysaccharide-selenium nanoparticles (EPS-SeNPs, Se/EPS = 1/20, 1/1 and 4/3) in simulated gastric (SGF) and intestinal fluids (SIF) using kinetics models of Zero order, First order, Higuchi, Hixson-Crowell and Korsmeyer-Peppas. EPS-SeNPs showed an increase in size from 80-125 nm to 250-320 nm and more ambiguous boundary after gastrointestinal digestion. Se/EPS ratio and pH had significant influence on Se release. Se release kinetics from EPS-SeNPs (Se/EPS = 1/1 and 4/3 in SGF) followed a classical Fickian diffusion, in contrast to an erosion governed by macromolecular chains relaxation for Se/EPS = 1/20 in SIF. Se release from EPS-SeNPs (Se/EPS = 1/1 and 4/3 in SIF) was well-fitted to Korsmeyer-Peppas model and followed a non-Fickian mechanism controlled by both diffusion and erosion. Additionally, EPS-SeNPs (Se/EPS = 1/20) showed a low Se release after SGF digestion, but a high release after SIF digestion, suggesting its application in controlled release of Se-enriched supplements for Se-deficiency treatment.

Recent advances in functionalized nanomaterials for the diagnosis and treatment of bacterial infections

The growing problem of resistant infections due to antibiotic misuse is a worldwide concern that poses a grave threat to healthcare systems. Thus, it is necessary to discover new strategies to combat infectious diseases. In this review, we provide a selective overview of recent advances in the use of nanocomposites as alternatives to antibiotics in antimicrobial treatments. Metals and metal oxide nanoparticles (NPs) have been associated with inorganic and organic supports to improve their antibacterial activity and stability as well as other properties. For successful antibiotic treatment, it is critical to achieve a high drug concentration at the infection site. In recent years, the development of stimuli-responsive systems has allowed the vectorization of antibiotics to the site of infection. These nanomaterials can be triggered by various mechanisms (such as changes in pH, light, magnetic fields, and the presence of bacterial enzymes); additionally, they can improve antibacterial efficacy and reduce side effects and microbial resistance. To this end, various types of modified polymers, lipids, and inorganic components (such as metals, silica, and graphene) have been developed. Applications of these nanocomposites in diverse fields ranging from food packaging, environment, and biomedical antimicrobial treatments to diagnosis and theranosis are discussed.

Conversional fluorescent kiwi peel phenolic extracts: Sensing of Hg2+ and Cu2+, imaging of HeLa cells and their antioxidant activity

The valorization, resource generation and the functional characteristic exploration of domestic waste still face enormous challenges. Kiwi peels, a common kind of fruit waste, contain a large amount of phenolic substances, including polyphenols, flavonoids, etc., which can be explored and reused in food and biomedical fields. By ultrasonic assisted extraction technology, we obtained conversional fluorescence kiwi peel phenolic extracts (PE) which possessed gradient magenta fluorescence relying on the content of ethanol in the solution, as well as strong antioxidant activity. Besides, metal ions sensing assay revealed that PE can specifically sense Hg²⁺ and Cu²⁺ (LOD: 1.16 and 0.17 μM, respectively) accompanied with a fluorescence conversion from magenta fluorescence to blue. Moreover, employing the prepared PE as fluorescent probes, imaging of HeLa cells can be easily achieved with satisfactory resolution. Additionally, PE was incorporated into the gelatin matrix, successfully fabricating a green, edible degradable film with excellent antioxidant activity.

Meticulous Doxorubicin Release from pH-Responsive Nanoparticles Entrapped within an Injectable Thermoresponsive Depot

The dual stimuli-controlled release of doxorubicin from gel-embedded nanoparticles is reported. Non-cytotoxic polymer nanoparticles are formed from poly(ethylene glycol)-b-poly(benzyl glutamate) that, uniquely, contain a central ester link. This connection renders the nanoparticles pH-responsive, enabling extensive doxorubicin release in acidic solutions (pH 6.5), but not in solutions of physiological pH (pH 7.4). Doxorubicin-loaded nanoparticles were found to be stable for at least 31 days and lethal against the three breast cancer cell lines tested. Furthermore, doxorubicin-loaded nanoparticles could be incorporated within a thermoresponsive poly(2-hydroxypropyl methacrylate) gel depot, which forms immediately upon injection of poly(2-hydroxypropyl methacrylate) in dimethyl sulfoxide solution into aqueous solution. The combination of the poly(2-hydroxypropyl methacrylate) gel and poly(ethylene glycol)-b-poly(benzyl glutamate) nanoparticles yields an injectable doxorubicin delivery system that facilities near-complete drug release when maintained at elevated temperatures (37 °C) in acidic solution (pH 6.5). In contrast, negligible payload release occurs when the material is stored at room temperature in non-acidic solution (pH 7.4). The system has great potential as a vehicle for the prolonged, site-specific release of chemotherapeutics.

Development of Metronidazole Loaded Chitosan Nanoparticles Using QbD Approach-A Novel and Potential Antibacterial Formulation

The aim of this study was to design, optimize, and develop metronidazole (Met) loaded nanoparticles (MetNp) by employing quality-based design (QbD) as well as a risk assessment methodology. A fractional factorial design was used by selecting five independent variables viz., chitosan concentration, tripolyphosphate concentration, and acetic acid concentration as material attributes, stirring speed, and stirring time as process parameters, whereby their influence on two dependent variables such as particle size (PS) and %entrapment efficiency (%EE) was studied. MetNp were synthesized by employing an ionic-gelation technique and optimized formula obtained from the QbD design study. PS and %EE studies revealed the formation of MetNp with 558.06 ± 2.52 nm and 59.07 ± 2.15%, respectively. Furthermore, a Met release study in various simulated gastro-intestinal media suggested pH-triggered (pH > 7.0) and sustained release profile of Met from Eudragit S100 enteric-coated MetNp capsule (MetNp cap). Moreover, the stability investigation of formulations confirmed good stability with respect to their PS and residual drug content (RDC) at different temperature conditions. In conclusion, the QbD method was effectively utilized in the development of MetNp and enteric-coated MetNp cap depicting their potential to release Met through MetNp cap only in the colon region and can be utilized for the treatment of amoebiasis in the colon.

Agricultural and Biomedical Applications of Chitosan-Based Nanomaterials

Chitosan has emerged as a biodegradable, nontoxic polymer with multiple beneficial applications in the agricultural and biomedical sectors. As nanotechnology has evolved as a promising field, researchers have incorporated chitosan-based nanomaterials in a variety of products to enhance their efficacy and biocompatibility. Moreover, due to its inherent antimicrobial and chelating properties, and the availability of modifiable functional groups, chitosan nanoparticles were also directly used in a variety of applications. In this review, the use of chitosan-based nanomaterials in agricultural and biomedical fields related to the management of abiotic stress in plants, water availability for crops, controlling foodborne pathogens, and cancer photothermal therapy is discussed, with some insights into the possible mechanisms of action. Additionally, the toxicity arising from the accumulation of these nanomaterials in biological systems and future research avenues that had gained limited attention from the scientific community are discussed here. Overall, chitosan-based nanomaterials show promising characteristics for sustainable agricultural practices and effective healthcare in an eco-friendly manner.

Intrinsic stimuli-responsive nanocarriers for smart drug delivery of antibacterial agents-An in-depth review of the last two decades

Antibiotic resistance due to suboptimal targeting and inconsistent antibiotic release at bacterial infection sites has driven the formulation of stimuli-responsive nanocarriers for antibacterial therapy. Unlike conventional nanocarriers, stimuli-responsive nanocarriers have the ability to specifically enhance targeting and drug release profiles. There has been a significant escalation in the design and development of novel nanomaterials worldwide; in particular, intrinsic stimuli-responsive antibiotic nanocarriers, due to their enhanced activity, improved targeted delivery, and superior potential for bacterial penetration and eradication. Herein, we provide an extensive and critical review of pH-, enzyme-, redox-, and ionic microenvironment-responsive nanocarriers that have been reported in literature to date, with an emphasis on the mechanisms of drug release, the nanomaterials used, the nanosystems constructed and the antibacterial efficacy of the nanocarriers. The review also highlights further avenues of research for optimizing their potential and commercialization. This review confirms the potential of intrinsic stimuli-responsive nanocarriers for enhanced drug delivery and antibacterial killing. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Encapsulation of Red Propolis in Polymer Nanoparticles for the Destruction of Pathogenic Biofilms

Microbial biofilms, structured communities of microorganisms, have been often associated to the infection and bacterial multiresistance problem. Conventional treatment of infection involves the use of antibiotics, being an alternative approach is the use of red propolis, a natural product, to prepare polymer nanoparticles. The aim of the present study was to encapsulate red propolis extract in poly(lactic-co-glycolic acid) (PLGA) nanoparticles for destruction in vitro of pathogenic biofilms. Poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) containing red propolis hydroethanolic extract (2 mg/mL) were produced by emulsification solvent diffusion method. The extract and developed nanoparticles were analyzed for antimicrobial activity and inhibition of bacterial biofilm formation in vitro against Staphylococcus aureus and Pseudomonas aeruginosa. Transmission electron microscopy images confirmed spherical nanoparticles in the range size from 42.4 nm (PLGA NPs) to 69.2 nm (HERP PLGA NPs), with encapsulation efficiencies of 96.99%. The free extract and encapsulated in polymer nanoparticle presented antimicrobial potential, with a minimum inhibitory concentration from 15.6 to 125 μg mL^-1 and from 100 to 1560 μg mL^-1 to inhibit biofilm formation for the Staphylococcus aureus and Pseudomonas aeruginosa, respectively.