Chitosan nanoparticles: Preparation, size evolution and stability

Experimental and Chitosan-Infused Adhesive with Dentin Pretreated with Femtosecond Laser, Methylene Blue-Activated Low-Level Laser, and Phosphoric Acid

Aim: To prepare experimental adhesive (EA) with 1% and without chitosan nanoparticles on dentin conditioned with a conventional technique phosphoric acid (PA) compared with two different contemporary techniques: photodynamic therapy (PDT) and femtosecond laser (FSL). Method: The methodology consisted of synthesis of EA and 1% chitosan-modified adhesive (CMA). Scanning electron microscopy, dentin adhesive interface assessment, energy-dispersive spectroscopy, shear bond strength (SBS), degree of conversion (DC), and bond failure were assessed. Teeth were selected, disinfected, and mounted in acrylic up to the cementoenamel junction. Occlusal enamel was removed and teeth were randomly allocated into groups and conditioned. These included Group 1: samples treated with PA; Group 2: specimens conditioned with methylene blue photosensitizer (MBP) activated by PDT; and Group 3: samples conditioned with FSL. Following different conditioning regimes, specimens were bonded using 1% CMA and EA. The composite buildup was followed by SBS testing and a bond failure assessment. DC was assessed for both EA and CMA. Analysis of variance and Tukey's post hoc test were used to compare the mean and standard deviation of SBS and DC in different experimental groups, with a significance level of p < 0.05. Results: Dentin pretreated with etch and rinse demonstrated the highest bond strength with 1% CMA. Dentin conditioned with MBP activated by PDT and bonded to EA showed the lowest bond scores. Overall SBS values of 1% CMA were better than EA irrespective of the conditioning regime of dentin. The DC was higher in EA adhesive. This was followed by DC in 1% CMA. DC in EA was found to be comparable with 1% CMA. Conclusions: PA remains the gold standard for dentin conditioning. The incorporation of 1% chitosan in adhesive improves SBS and results in no change in DC. The use of FSL in dentin conditioning can be used as an alternative approach as it results in SBS within acceptable limits. The study was approved by the ethical board of King Saud University.

Nanoassemblies of Chitosan-Based Polyelectrolyte Complexes as Nucleic Acid Delivery Systems

Nucleic acid delivery requires vectorization for protection from nucleases, preventing clearance by the reticuloendothelial system, and targeting to allow cellular uptake. Nanovectors meeting the above specifications should be safe for the patient, simple to manufacture, and display long-term stability. Our nanovectors were obtained via the green process of polyelectrolyte complexation, carried out at 25 °C in water at a low shear rate using chitosan (a polycationic biocompatible polysaccharide of specific molar mass and acetylation degree) and dextran sulfate as a polyanionic biocompatible polysaccharide. These complexes formed nanoassemblies of primary nanoparticles (20-35 nm) and maintained their colloidal stability for over 1 year at 25 °C. They could be steam sterilized, and a model nucleic acid could be either encapsulated or surface adsorbed. A targeting agent was finally bound to their surface. This work serves as a proof of concept of the suitability of chitosan-based polyelectrolyte complexes as nanovectors by sequential multilayered adsorption of various biomacromolecules.

Development and optimization of vildagliptin solid lipid nanoparticles loaded ocuserts for controlled ocular delivery: A promising approach towards treating diabetic retinopathy

Diabetes mellitus (DM) is the most prevalent cause of diabetic retinopathy (DRP). DRP has been recognized for a long time as a microvascular disease. Many drugs were used to treat DRP, including vildagliptin (VLD). In addition to its hypoglycemic effect, VLD minimizes ocular inflammation and improves retinal blood flow for individuals with type 2 diabetes mellitus. Nevertheless, VLD can cause upper respiratory tract infections, diarrhea, nausea, hypoglycemia, and poor tolerability when taken orally regularly due to its high water solubility and permeability. Effective ocular administration of VLD is achieved using solid lipid nanoparticles (SLNPs), which improve corneal absorption, prolonged retention, and extended drug release. Ocuserts (OCUs) are sterile, long-acting ocular dosage forms that diminish the need for frequent dosing while improving residence time and stability. Therefore, this study intends to develop VLD solid lipid nanoparticle OCUs (VLD-SLNPs-OCUs) to circumvent the issues commonly associated with VLD. SLNPs were prepared using the double-emulsion/melt dispersion technique. The optimal formula has been implemented in OCUs. Optimization and development of VLD-SLNPs-OCUs were performed using a Box-Behnken Design (BBD). VLD-SLNPs-OCUs loading efficiency was 95.28 ± 2.87%, and differential scanning calorimetry data (DSC) showed the full transformation of VLD to an amorphous state and the excellent distribution in the prepared OCUs matrices. The in vivo release of VLD from the optimized OCUs after 24 h was 35.12 ± 2.47%, consistent with in vitro drug release data of 36.89 ± 3.11. The optimized OCUs are safe to use in the eye, as shown by the ocular irritation test. VLD-SLNPs-OCUs provide extended VLD release, an advantageous alternative to conventional oral dose forms, resulting in fewer systemic adverse effects and less variation in plasma drug levels. VLD-SLNPs-OCUs might benefit retinal microvascular blood flow beyond blood glucose control and may be considered a promising approach to treating diabetic retinopathy.

Chitosan: A Versatile Biomaterial Revolutionizing Endodontic Therapy

Owing to their nanoscale dimensions, nanomaterials have special chemical and physical properties that set them apart from their bulk counterparts. The exterior dimensions of a minimum of half of the particles span several nanometers in their size distribution. Silver nanoparticles (AgNPs) are one type of nanomaterial that has been widely used because of their strong antibacterial properties, which can kill bacteria that are resistant to many drugs. Due to its potential for regulated release, localized retention, and safeguarding the active ingredients against environmental or enzymatic deterioration, nanoparticle technology has also emerged as a promising medication delivery method. The techniques for creating nanoparticles can be easily scaled up and used for a wide variety of medications. Since polymeric nanoparticles are biodegradable, biocompatible, and have more readily available formulation techniques than other nanoparticle drug delivery approaches, their range of applications has been expanding. Chitosan, also known as deacetylated polysaccharide, is a straight-chain cationic polymer that is typically a cationic copolymer. It can be generated naturally or by deacetylating chitin. Consequently, it contains an extensive array of biomedical applications, such as efficient healing of wounds, regeneration of tissues, regeneration of bone, and anti-infection. Because of its functional diversity, accessibility, and being both biodegradable and biocompatible, it has a wide spectrum of uses in dentistry. Recent research on chitosan-based nanoparticles is founded on the field's growing comprehension of the characteristics of chitosan and techniques for chemical or physical modification that are used to optimize the drug loading and release characteristics of the nanoparticles.

Exploring the Biofilm Inhibition Potential of a Novel Phytic Acid-Crosslinked Chitosan Nanoparticle: In Vitro and In Vivo Investigations

The primary factor underlying the virulence of Candida albicans is its capacity to form biofilms, which in turn leads to recurrent complications. Over-the-counter antifungal treatments have proven ineffective in eliminating fungal biofilms and the inflammatory cytokines produced during fungal infections. Chitosan nanoparticles offer broad and versatile therapeutic potential as both antifungal agents and carriers for antifungal drugs to combat biofilm-associated Candida infections. In our study, we endeavoured to develop chitosan nanoparticles utilising chitosan and the antifungal crosslinker phytic acid targeting C. albicans. Phytic acid, known for its potent antifungal and anti-inflammatory properties, efficiently crosslinks with chitosan. The nanoparticles were synthesised using the ionic gelation technique and subjected to analyses including Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential analysis. The synthesised nanoparticles exhibited dimensions with a diameter (Dh) of 103 ± 3.9 nm, polydispersity index (PDI) of 0.33, and zeta potential (ZP) of 37 ± 2.5 mV. These nanoparticles demonstrated an antifungal effect with a minimum inhibitory concentration (MIC) of 140 ± 2.2 µg/mL, maintaining cell viability at approximately 90% of the MIC value and reducing cytokine levels. Additionally, the nanoparticles reduced ergosterol content and exhibited a 62% ± 1.2 reduction in biofilm susceptibility, as supported by colony-forming unit (CFU) and XTT assays-furthermore, treatment with nanoparticles reduced exopolysaccharide production and decreased secretion of aspartyl protease by C. albicans. Our findings suggest that the synthesised nanoparticles effectively combat Candida albicans infections. In vivo studies conducted on a mouse model of vaginal candidiasis confirmed the efficacy of the nanoparticles in combating fungal infections in vivo.

Chitosan-based nanosystems for cancer diagnosis and therapy: Stimuli-responsive, immune response, and clinical studies

Cancer, a global health challenge of utmost severity, necessitates innovative approaches beyond conventional treatments (e.g., surgery, chemotherapy, and radiation therapy). Unfortunately, these approaches frequently fail to achieve comprehensive cancer control, characterized by inefficacy, non-specific drug distribution, and the emergence of adverse side effects. Nanoscale systems based on natural polymers like chitosan have garnered significant attention as promising platforms for cancer diagnosis and therapy owing to chitosan's inherent biocompatibility, biodegradability, nontoxicity, and ease of functionalization. Herein, recent advancements pertaining to the applications of chitosan nanoparticles in cancer imaging and drug/gene delivery are deliberated. The readers are introduced to conventional non-stimuli-responsive and stimuli-responsive chitosan-based nanoplatforms. External triggers like light, heat, and ultrasound and internal stimuli such as pH and redox gradients are highlighted. The utilization of chitosan nanomaterials as contrast agents or scaffolds for multimodal imaging techniques e.g., magnetic resonance, fluorescence, and nuclear imaging is represented. Key applications in targeted chemotherapy, combination therapy, photothermal therapy, and nucleic acid delivery using chitosan nanoformulations are explored for cancer treatment. The immunomodulatory effects of chitosan and its role in impacting the tumor microenvironment are analyzed. Finally, challenges, prospects, and future outlooks regarding the use of chitosan-based nanosystems are discussed.

Nasal Immunization Using Chitosan Nanoparticles with Glycoprotein B of Murine Cytomegalovirus

The use of nanoparticles as a delivery system for a specific antigen could solve many limitations of mucosal vaccine applications, such as low immunogenicity, or antigen protection and stabilization. In this study, we tested the ability of nasally administered chitosan nanoparticles loaded with glycoprotein B of murine cytomegalovirus to induce an immune response in an animal model. The choice of chitosan nanoparticle type was made by in vitro evaluation of sorption efficiency and antigen release. Three types of chitosan nanoparticles were prepared: crosslinked with tripolyphosphate, coated with hyaluronic acid, and in complex with polycaprolactone. The hydrodynamic size of the nanoparticles by dynamic light scattering, zeta potential, Fourier transform infrared spectroscopy, scanning electron microscopy, stability, loading efficiency, and release kinetics with ovalbumin were evaluated. Balb/c mice were immunized intranasally using the three-dose protocol with nanoparticles, gB, and adjuvants Poly(I:C) and CpG ODN. Subsequently, the humoral and cell-mediated antigen-specific immune response was determined. On the basis of the properties of the tested nanoparticles, the cross-linked nanoparticles were considered optimal for further investigation. The results show that nanoparticles with Poly(I:C) and with gB alone raised IgG antibody levels above the negative control. In the case of mucosal IgA, only gB alone weakly induced the production of IgA antibodies compared to saline-immunized mice. The number of activated cells increased slightly in mice immunized with nanoparticles and gB compared to those immunized with gB alone or to negative control. The results demonstrated that chitosan nanoparticles could have potential in the development of mucosal vaccines.

Recent Advances in Topical Hemostatic Materials

Untimely or improper treatment of traumatic bleeding may cause secondary injuries and even death. The traditional hemostatic modes can no longer meet requirements of coping with complicated bleeding emergencies. With scientific and technological advancements, a variety of topical hemostatic materials have been investigated involving inorganic, biological, polysaccharide, and carbon-based hemostatic materials. These materials have their respective merits and defects. In this work, the application and mechanism of the major hemostatic materials, especially some hemostatic nanomaterials with excellent adhesion, good biocompatibility, low toxicity, and high adsorption capacity, are summarized. In the future, it is the prospect to develop multifunctional hemostatic materials with hemostasis and antibacterial and anti-inflammatory properties for promoting wound healing.

Hybrid hydrogels support neural cell culture development under magnetic actuation at high frequency

The combination of hydrogels and magnetic nanoparticles, scarcely explored to date, offers a wide range of possibilities for innovative therapies. Herein, we have designed hybrid 3D matrices integrating natural polymers, such as collagen, chitosan (CHI) and hyaluronic acid (HA), to provide soft and flexible 3D networks mimicking the extracellular matrix of natural tissues, and iron oxide nanoparticles (IONPs) that deliver localized heat when exposed to an alternating magnetic field (AMF). First, colloidally stable nanoparticles with a hydrodynamic radius of ∼20 nm were synthesized and coated with either CHI (NPCHI) or HA (NPHA). Then, collagen hydrogels were homogeneously loaded with these coated-IONPs resulting in soft (E0 ∼ 2.6 kPa), biodegradable and magnetically responsive matrices. Polymer-coated IONPs in suspension preserved primary neural cell viability and neural differentiation even at the highest dose (0.1 mg Fe/mL), regardless of the coating, even boosting neuronal interconnectivity at lower doses. Magnetic hydrogels maintained high neural cell viability and sustained the formation of highly interconnected and differentiated neuronal networks. Interestingly, those hydrogels loaded with the highest dose of NPHA (0.25 mgFe/mg polymer) significantly impaired non-neuronal differentiation with respect to those with NPCHI. When evaluated under AMF, cell viability slightly diminished in comparison with control hydrogels magnetically stimulated, but not compared to their counterparts without stimulation. Neuronal differentiation under AMF was only affected on collagen hydrogels with the highest dose of NPHA, while non-neuronal differentiation regained control values. Taken together, NPCHI-loaded hydrogels displayed a superior performance, maybe benefited from their higher nanomechanical fluidity. STATEMENT OF SIGNIFICANCE: Hydrogels and magnetic nanoparticles are undoubtedly useful biomaterials for biomedical applications. Nonetheless, the combination of both has been scarcely explored to date. In this study, we have designed hybrid 3D matrices integrating both components as promising magnetically responsive platforms for neural therapeutics. The resulting collagen scaffolds were soft (E0 ∼ 2.6 kPa) and biodegradable hydrogels with capacity to respond to external magnetic stimuli. Primary neural cells proved to grow on these substrates, preserving high viability and neuronal differentiation percentages even under the application of a high-frequency alternating magnetic field. Importantly, those hydrogels loaded with chitosan-coated iron oxide nanoparticles displayed a superior performance, likely related to their higher nanomechanical fluidity.

Chitosan and Anionic Solubility Enhancer Sulfobutylether-β-Cyclodextrin-Based Nanoparticles as Dexamethasone Ophthalmic Delivery System for Anti-Inflammatory Therapy

Cataract surgery interventions are constantly increasing, particularly among adult and elderly patients. This type of surgery can lead to inflammatory states of the ocular anterior segment (AS), usually healed via postoperative treatment with dexamethasone (DEX)-containing eye drops. The application of eye drops is challenging due to the high number of daily administrations. In this study, mucoadhesive nanoparticles (NPs) were formulated to improve the residence time of DEX on the corneal mucosa, enhancing the drug's solubility and bioavailability. The NPs were generated using an ionotropic gelation technique, exploiting the interaction between the cationic group of chitosan (CS) and the anionic group of sulfobutylether-β-cyclodextrin (SBE-β-CD). The formation of the inclusion complex and its stoichiometry were studied through phase solubility studies, Job's plot method, and Bi-directional transport studies on MDCKII-MDR1. The obtained NPs showed good chemical and physical characteristics suitable for drug loading and subsequent testing on animal mucosa. The DEX-loaded CS/SBE-β-CD NPs exhibited a prolonged residence time on animal mucosa and demonstrated enhanced drug permeability through the corneal membrane, showing a sustained release profile. The developed NPs posed no irritation or toxicity concerns upon local administration, making them an optimal and innovative drug delivery system for inflammatory AS diseases treatment.

Novel biomimetic peptide-loaded chitosan nanoparticles improve dentin bonding via promoting dentin remineralization and inhibiting endogenous matrix metalloproteinases

OBJECTIVE

This study aims to synthesize novel chitosan nanoparticles loaded with an amelogenin-derived peptide QP5 (TMC-QP5/NPs), investigate their remineralization capability and inhibitory effects on endogenous matrix metalloproteinases (MMPs), and evaluate the dentin bonding properties of remineralized dentin regulated by TMC-QP5/NPs.

METHODS

TMC-QP5/NPs were prepared by ionic crosslinking method and characterized by dynamic light scattering method, scanning electron microscopy, transmission electron microscope, atomic force microscope, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The encapsulation and loading efficiency of TMC-QP5/NPs and the release of QP5 were examined. To evaluate the remineralization capability of TMC-QP5/NPs, the mechanical properties, and the changes in structure and composition of differently conditioned dentin were characterized. The MMPs inhibitory effects of TMC-QP5/NPs were explored by MMP Activity Assay and in-situ zymography. The dentin bonding performance was detected by interfacial microleakage and microshear bond strength (μSBS).

RESULTS

TMC-QP5/NPs were successfully synthesized, with uniform size, good stability and biosafety. The encapsulation and loading efficiency of TMC-QP5/NPs was respectively 69.63 ± 2.22% and 13.21 ± 0.73%, with a sustained release of QP5. TMC-QP5/NPs could induce mineral deposits on demineralized collagen fibers and partial occlusion of dentin tubules, and recover the surface microhardness of dentin, showing better remineralization effects than QP5. Besides, TMC-QP5/NPs significantly inhibited the endogenous MMPs activity. The remineralized dentin induced by TMC-QP5/NPs exhibited less interfacial microleakage and higher μSBS, greatly improved dentin bonding.

SIGNIFICANCE

This novel peptide-loaded chitosan nanoparticles improved resin-dentin bonding by promoting dentin remineralization and inactivating MMPs, suggesting a promising strategy for optimizing dentin adhesive restorations.

Optimize the parameters for the synthesis by the ionic gelation technique, purification, and freeze-drying of chitosan-sodium tripolyphosphate nanoparticles for biomedical purposes

BACKGROUND

Polymeric nanoparticles can be used for wound closure and therapeutic compound delivery, among other biomedical applications. Although there are several nanoparticle obtention methods, it is crucial to know the adequate parameters to achieve better results. Therefore, the objective of this study was to optimize the parameters for the synthesis, purification, and freeze-drying of chitosan nanoparticles. We evaluated the conditions of agitation speed, anion addition time, solution pH, and chitosan and sodium tripolyphosphate concentration.

RESULTS

Chitosan nanoparticles presented an average particle size of 172.8 ± 3.937 nm, PDI of 0.166 ± 0.008, and zeta potential of 25.00 ± 0.79 mV, at the concentration of 0.1% sodium tripolyphosphate and chitosan (pH 5.5), with a dripping time of 2 min at 500 rpm. The most representative factor during nanoparticle fabrication was the pH of the chitosan solution, generating significant changes in particle size and polydispersity index. The observed behavior is attributed to the possible excess of sodium tripolyphosphate during synthesis. We added the surfactants poloxamer 188 and polysorbate 80 to evaluate the stability improvement during purification (centrifugation or dialysis). These surfactants decreased coalescence between nanoparticles, especially during purification. The centrifugation increased the zeta potential to 40.8-56.2 mV values, while the dialyzed samples led to smaller particle sizes (152-184 nm). Finally, freeze-drying of the chitosan nanoparticles proceeded using two cryoprotectants, trehalose and sucrose. Both adequately protected the system during the process, and the sugar concentration depended on the purification process.

CONCLUSIONS

In Conclusion, we must consider each surfactant's benefits in formulations for selecting the most suitable. Also, it is necessary to do more studies with the molecule to load. At the same time, the use of sucrose and trehalose generates adequate protection against the freeze-drying process, even at a 5% w/v concentration. However, adjusting the percentage concentration by weight must be made to work with the CS-TPP NPs purified by dialysis.

Chicken embryo model for in vivo acute toxicological and antitumor efficacy evaluation of lipid nanocarrier containing doxorubicin

Nanoencapsulation of chemotherapeutics, including doxorubicin, can endow the formulations with unique properties, such as a decrease in adverse effects and toxicity. The chicken embryo model is an alternative and well-accepted strategy for evaluating the toxicity and efficacy of drugs and nanoformulations. Therefore, this study proposes the development of a new lipid nanocarrier for doxorubicin delivery (NanoLip-Dox) and posterior evaluation of toxicological profile and antitumoral efficacy against a breast tumor in chicken embryos. NanoLip-Dox showed a unimodal particle size (< 150 nm), negative zeta potential (-19.5 mV), absence of drug crystals, drug content of 0.099 mg·mL-1, and high entrapment efficiency (95%). NanoLip-Dox did not cause toxicity in the chicken embryos; in contrast, doxorubicin hydrochloride induced moderate irritation in the chorioallantoic membrane (at 862.1 μmol·L-1), a survival rate of 50% (at 1.7 μmol·L-1), and an increase in aspartate aminotransferase (at 862.1, 344.8, and 172.4 μmol·L-1). In addition, NanoLip-Dox (at 1.7 μmol·L-1) showed potent antitumor efficacy with a high tumor remission percentage (40.9 ± 9.7%) compared to the control group (8.6 ± 14.8%). These findings together with the absence of toxicity concerning morphological characteristics, weights of embryos and organs, hematologic parameters, and enzymatic activity (alanine aminotransferase, aspartate aminotransferase, and creatinine) suggest the safety and efficacy of NanoLip-Dox.

NAD+-associated-hyaluronic acid and poly(L-lysine) polyelectrolyte complexes: An evaluation of their potential for ocular drug delivery

This study details the formation and characterisation of a novel nicotinamide adenine dinucleotide (NAD+)-associated polymeric nanoparticle system. The development of a polyelectrolyte complex (PEC) composed of two natural polyelectrolytes, hyaluronic acid and poly(L-lysine), and an evaluation of its suitability for NAD+ ocular delivery, primarily based on its physicochemical properties and in vitro release profile under physiological ocular flow rates, were of key focus. Following optimisation of formulation method conditions such as complexation pH, mode of addition, and charge ratio, the PEC was successfully formulated under mild formulation conditions via polyelectrolyte complexation. With a size of 235.1 ± 19.0 nm, a PDI value of 0.214 ± 0.140, and a zeta potential value of - 38.0 ± 1.1 mV, the chosen PEC, loaded with 430 µg of NAD+ per mg of PEC, exhibited non-Fickian, sustained release at physiological flowrates of 10.9 ± 0.2 mg of NAD+ over 14 h. PECs containing up to 200 µM of NAD+ did not induce any significant cytotoxic effects on an immortalised human corneal epithelial cell line. Using fluorescent labeling, the NAD+-associated PECs demonstrated retention within the corneal epithelium layer of a porcine model up to 6 h post incubation under physiological conditions. A study of the physicochemical behaviour of the PECs, in terms of size, zeta potential and NAD+ complexation in response to environmental stimuli,highlighted the dynamic nature of the PEC matrix and its dependence on both pH and ionic condition. Considering the successful formation of reproducible NAD+-associated PECs with suitable characteristics for ocular drug delivery via an inexpensive formulation method, they provide a promising platform for NAD+ ocular delivery with a strong potential to improve ocular health.

Chitosan Nanoparticles Loaded with Capparis cartilaginea Decne Extract: Insights into Characterization and Antigenotoxicity In Vivo

Plant-based foods may enhance the prevention of cancer. The present investigation aimed to assess the antigenotoxic effects of chitosan nanoparticles (CNPs) when loaded with the ethanol extract of C. cartilaginea (CNPs/Cc). Synthesis of CNPs and CNPs/Cc and their characterization were carried out using TEM, EDS, DSC, and Zeta potential. For in vivo experiments, animal groups were treated in the following groups: negative control, ethyl methanesulfonate (EMS) (240 mg/kg), CNPs (350 mg/kg), high and low doses of CNPs/Cc, CNPs plus EMS, high dose of CNPs/Cc plus EMS, and low dose of CNPs/Cc plus EMS. Bone marrow chromosomal aberrations and sperm shape abnormalities were examined. TEM results showed that CNPs and CNPs/Cc are spherical particles. CNPs' physical stability was observed to be lower than that of CNPs/Cc due to the presence of more positive charges on CNPs/Cc. EMS significantly enhanced chromosomal abnormalities and sperm shape abnormalities. CNPs showed powerful antigenotoxic properties. For the first time, it could be concluded that loading chitosan nanoparticles with C. cartilaginea extract significantly promotes its protective properties.

Biocompatible antibiotic-loaded mesoporous silica/bioglass/collagen-based scaffolds as bone drug delivery systems

Local delivery of antibiotics has gained increasing interest in the treatment of osteomyelitis due to its effectiveness and safety. Since the regeneration of bone tissue at the site of infection is as important as bacterial eradication, implantable drug delivery systems should not only release the drugs in a proper manner but also exert the osseointegration capability. Herein, we present an implantable drug delivery system in a scaffold form with a unique set of features for local treatment of osteomyelitis. For the first time, collagen type I, ciprofloxacin-loaded mesoporous silica, and bioglass were combined to obtain scaffolds using the molding method. Drug-loaded mesoporous silica was blended with polydimethylsiloxane to prolong the drug release, whereas bioglass served as a remineralization agent. Collagen-silica scaffolds were evaluated in terms of physicochemical properties, drug release rate, mineralization potential, osteoblast response in vitro, antimicrobial activity, and biological properties using an in vivo preclinical model - chick embryo chorioallantoic membrane (CAM). The desirable multifunctionality of the proposed collagen-silica scaffolds was confirmed. They released the ciprofloxacin for 80 days, prevented biofilm development, and induced hydroxyapatite formation. Moreover, the resulting macroporous structure of the scaffolds promoted osteoblast attachment, infiltration, and proliferation. Collagen-silica scaffolds were also biocompatible and effectively integrated with CAM.

Ameliorative effect of chitosan nanoparticles in capacitation media on post-thawing in vitro fertilizing ability of bovine spermatozoa

This study aimed to investigate the effect of supplementation of chitosan nanoparticles (CSNPs) on the capacitation of bovine spermatozoa during the in vitro fertilization process. Hyperactivated motility (HAM) and acrosome reaction (AR) of sperm cells as well as in vitro fertilization and cleavage rates are the main parameters used to estimate the effect of CSNPs on bovine spermatozoa's fertilizing ability. In this study, three different concentrations of CSNPs (10, 20 and 100 μg/mL) were prepared and characterized. Motile spermatozoa were separated from frozen-thawed semen by a swim-up technique and capacitated in Sperm-TALP medium supplemented with heparin only without CSNPs treatment (positive control), heparin + 10 μg/mL CSNPs, heparin + 20 μg/mL CSNPs, heparin + 100 μg/mL CSNPs and the last one served as a negative control tube which supplemented with 10 μg/mL CSNPs without adding heparin. Sperm cells were incubated for 90 min at 39°C in a 5% CO2 incubator and evaluated every 30 min at intervals. Cumulus oophorus complex (COCs) were matured in a 5% CO2 incubator at 39°C and inseminated in vitro with frozen-thawed bull sperm of the above concentrations. The inseminated oocytes were incubated at 39°C in a 5% CO2 incubator for 24 h and then examined for evidence of fertilization. The results of this investigation showed that HAM and AR were best affected by CSNPs at a concentration of 20 μg/mL during an incubation time of 60 min. As time went on, the overall proportion of spermatozoa with progressive motility (PM) decreased across all groups, and a substantially lower value was found at the dose mentioned above. Additionally, the impact of sperm treated with CSNPs on fertilization rate was assessed. The outcomes demonstrated that in comparison to the other concentrations (10 and 100 μg/mL), the positive control and the negative control, the proportion of fertilized oocytes was significantly higher in the CSNPs concentration (20 μg/mL). In conclusion, it could be inferred from this investigation that CSNPs support sperm functions during IVF and can be used for biomedical interventions in bovine spermatozoa. Additionally, a high IVF rate was achieved by using sperm treated with CSNPs as CSNPs enhance sperm capacitation and acrosome reaction.

Myricetin encapsulated chitosan nanoformulation for management of type 2 diabetes: Preparation, optimization, characterization and in vivo activity

Type 2 diabetes mellitus (T2DM) is a serious and alarming disease attracting widespread attention. It is not a single metabolic disease; over time, it leads to serious disorders, namely, diabetic nephropathy, neuropathy, retinopathy and several cardiovascular, hepatocellular complications. The increase in T2DM cases in recent times has attracted significant attention. Currently, the medications available have side effects, and injectables are painful, causing trauma to the patients. Therefore, it is imperative to come up with oral delivery. In this background we report here a nanoformulation carrying natural small molecule Myricetin (MYR) encapsulated within Chitosan nanoparticles (CHT-NPs). MYR-CHT-NPs were prepared by ionic gelation method and evaluated using different characterization techniques. The in vitro release of MYR from CHT NPs in different physiological media showed pH dependence. in vivo pharmacodynamic study followed by oral administration in Albino Wistar rats showed better glycaemic control than existing drug. Further, the optimized nanoparticles also exhibited controlled increase in weight as compared to Metformin. The biochemistry profile of rats treated with nanoformulation reduced the levels of several pathological biomarkers, indicating additional benefits of MYR. Histopathological images exhibited no toxicity or changes in the major organs section in contrast to normal control, suggesting safe oral administration of the encapsulated MYR. Thus, we conclude that MYR-CHT-NPs represent an attractive delivery vehicle in improving the blood glucose level with controlled weight and have the potential to be safely administered orally for the management of T2DM.

Evaluation of the Antimicrobial Activity of Chitosan Nanoparticles against Listeria monocytogenes

Chitosan is obtained from the deacetylation of chitin, and it is known to possess antimicrobial activity. It has attracted attention as it may be used for treating infections caused by different types of microorganisms due to its broad spectrum. Its application in the form of micro- or nanoparticles (CM/CN) has expanded its usage, as in this form, it retains its activity, and remain stable in aqueous solutions. However, inconsistencies in the results reported by different authors have been identified. In this communication, the antimicrobial activity of CN produced from different starting materials was tested against Listeria monocytogenes. It was observed that, even though all the starting materials were reported to have a molecular weight (MW) below 200 kDa and degree of deacetylation (DD) > 75%, the size of the CNs were significantly different (263 nm vs. 607 nm). Furthermore, these differences in sizes exerted a direct effect on the antimicrobial properties of the particles, as when testing the ones with the smallest size, i.e., 263 nm, a lower Minimum Inhibitory Concentration (MIC) was achieved, i.e., 0.04 mg/mL. Even though the largest particles, i.e., 607 nm, in individual experiments were able to achieve an MIC of 0.03 mg/mL, the results with CN presented great variation among replicates and up to 0.2 mg/mL were needed in other replicates. The starting material has a critical impact on the properties of the CN, and it must be carefully characterized and selected for the intended application, and MW and DD solely do not fully account for these properties.

Chitosan Nanoparticle/Simvastatin for Experimental Maxillary Bony Defect Healing: A Histological and Histomorphometrical Study

Biomaterials such as chitosan and simvastatin (Sim) have been introduced to accelerate the extensive and multicellular biological process of bone healing. The aim of this study was to evaluate the bone healing potential of chitosan and Sim, alone or combined. Forty-two male New Zealand rabbits were divided into three groups: chitosan nanoparticles (ChN), Sim and chitosan simvastatin nanoparticles (ChSimN). Two bony defects were created in the maxillary bone. The hole on the right side received one of the experimental materials, while the other side was assigned as the control and left to heal without any intervention. Bone specimens were collected at 2 and 4 weeks and then taken for histological and histomorphometrical analyses. The histological findings revealed that ChN possessed the highest number of osteoblasts and osteoclasts at weeks 2 and osteocytes after 4 weeks. There was a significant difference between the two healing periods regarding all bone parameters across all groups. ChN stood out as the only group that had a significant difference in the count of all bone cells between the two periods, thus having the best potential in promoting bone healing.

A Review on Reinforcements and Additives in Starch-Based Composites for Food Packaging

The research of starch as a matrix material for manufacturing biodegradable films has been gaining popularity in recent years, indicating its potential and possible limitations. To compete with conventional petroleum-based plastics, an enhancement of their low resistance to water and limited mechanical properties is essential. This review aims to discuss the various types of nanofillers and additives that have been used in plasticized starch films including nanoclays (montmorillonite, halloysite, kaolinite, etc.), poly-saccharide nanofillers (cellulose, starch, chitin, and chitosan nanomaterials), metal oxides (titanium dioxide, zinc oxide, zirconium oxide, etc.), and essential oils (carvacrol, eugenol, cinnamic acid). These reinforcements are frequently used to enhance several physical characteristics including mechanical properties, thermal stability, moisture resistance, oxygen barrier capabilities, and biodegradation rate, providing antimicrobial and antioxidant properties. This paper will provide an overview of the development of starch-based nanocomposite films and coatings applied in food packaging systems through the application of reinforcements and additives.

Negatively charged chitosan nanoparticles prepared by ionotropic gelation for encapsulation of positively charged proteins

The nanoprecipitation of hydrogel nanoparticles by complex coacervation is investigated through a systematic study of the popular chitosan-polyphosphate pair of polyelectrolytes with opposite charges at pH 4. Polyphosphates of varying molar masses and electrical charges are investigated as alternatives to the commonly used tripolyphosphate, so as to assess the influence of the strength of electrostatic interactions on the fabrication possibility, the size of hydrogel particles, and their overall charge. Sodium hexametaphosphate and sodium polyphosphate allow the manufacture of such nanoparticles with either a positive or a negative charge, depending on the chitosan/polyphosphate ratio and the order of mixing. The classical way of mixing by pouring the polyphosphate solution into the chitosan solution yields microparticles. Inverting the order of mixing by pouring the chitosan solution into the polyphosphate solution allows the precipitation of negatively charged nanoparticles with diameters in the range 100-200 nm. Such charge inversion of the chitosan into negative is not possible with the common TPP. It was achieved using sodium hexametaphosphate and sodium polyphosphate having a larger negative charge. Charge inversion of chitosan allows an efficient encapsulation of positively charged proteins with an improved encapsulation efficiency than in the usual TPP-based coacervate. The encapsulation of the bovine serum albumin at pH 4 is given as a case study of a positively charged protein.

Hyaluronic Acid-Coated Chitosan/Gelatin Nanoparticles as a New Strategy for Topical Delivery of Metformin in Melanoma

Metformin is a multipotential compound for treating diabetes II and controlling hormonal acne and skin cancer. This study was designed to enhance metformin skin penetration in melanoma using nanoparticles containing biocompatible polymers. Formulations with various concentrations of chitosan, hyaluronic acid, and sodium tripolyphosphate were fabricated using an ionic gelation technique tailored by the Box-Behnken design. The optimal formulation was selected based on the smallest particle size and the highest entrapment efficiency (EE%) and used in ex vivo skin penetration study. In vitro antiproliferation activity and apoptotic effects of formulations were evaluated using MTT and flow cytometric assays, respectively. The optimized formulation had an average size, zeta potential, EE%, and polydispersity index of 329 ± 6.30 nm, 21.94 ± 0.05 mV, 64.71 ± 6.12%, and 0.272 ± 0.010, respectively. The release profile of the optimized formulation displayed a biphasic trend, characterized by an early burst release, continued by a slow and sustained release compared to free metformin. The ex vivo skin absorption exhibited 1142.5 ± 156.3 μg/cm² of metformin deposited in the skin layers for the optimized formulation compared to 603.2 ± 93.1 μg/cm² for the free metformin. Differential scanning calorimetry confirmed the deformation of the drug from the crystal structure to an amorphous state. The attenuated total reflection Fourier transform infrared results approved no chemical interaction between the drug and other ingredients of the formulations. According to the MTT assay, metformin in nanoformulation exhibited a higher cytotoxic effect against melanoma cancer cells than free metformin (IC₅₀: 3.94 ± 0.57 mM vs. 7.63 ± 0.26 mM, respectively, P < 0.001). The results proved that the optimized formulation of metformin could efficiently decrease cell proliferation by promoting apoptosis, thus providing a promising strategy for melanoma therapy.

Impact of molecular weight and deacetylation degree of chitosan on the bioaccessibility of quercetin encapsulated in alginate/chitosan-coated zein nanoparticles

This work aimed at studying the effect of molecular weight (MW) and degree of deacetylation (DD) of chitosan on the quercetin bioaccessibility encapsulated in alginate/chitosan-coated zein nanoparticles (alg/chiZN). The chitosan coating layer produced nanoparticulate systems with good stability parameters, high encapsulation efficiency (EE) and a higher bioaccessibilty of quercetin after in-vitro digestion. By increasing the DD of chitosan, the ζ-potential of the colloidal system significantly increased (≥27.1 mV), while low and very low MW chitosans generated systems with smaller particle sizes (≤ 277.8 nm) and polydispersity index [PDI (0.189)]. The best results, in terms of EE (≥84.44) and bioaccessibility (≥76.70), were obtained when the systems were prepared with low MW chitosan and high DD. Thus, the alg/chiZN nanocapsules may be a promising delivery system for improving the quercetin bioaccessibility or other compounds with a similar chemical nature, especially when higher DD and lower MWs are used.

Moringa oleifera gum capped MgO nanoparticles: Synthesis, characterization, cyto- and ecotoxicity assessment

Nano-based drug delivery research is increasing due to the therapeutic applications for human health care. However, traditional chemical capping-based synthesis methods lead to unwanted toxicity effects. Hence, there is an urgent need for green synthesis-based and biocompatible synthesis methods. The current work describes for the first time the green synthesis of Moringa gum-capped MgO nanoparticles (Mgm-MgO NPs). Their antioxidant activity, hemolysis potential, cytotoxicity, phytotoxicity, toxicity by chorioallantoic membrane (CAM) chick embryo assay and in vivo toxicity in zebrafish embryos were described. The Mgm-MgO NPs exhibited significant antioxidant activity. The Mgm-MgO NPs at 500 μg/ml produced significant hemolysis (72.54 %), while lower concentrations did not. Besides, the cytotoxicity assessment of the Mgm-MgO NPs was conducted in PA-1 cells from human ovarian teratocarcinoma by MTT assay. The Mgm-MgO NPs (0.1-500 μg/ml) considerably reduced the viability of PA-1 cells. Furthermore, Mgm-MgO NPs had no significant effect on seed germination but had a significant effect on root and shoot length of mungbean (Vigna radiata). Additionally, the CAM assay was used to analyze the antiangiogenic potential of Mgm-MgO NPs, exhibiting no significant alterations after 72 h. Finally, the zebrafish embryotoxicity assay revealed that the Mgm-MgO NPs (0.1-500 μg/ml) did not affect morphology, mortality or survival rate.

Starch physical treatment, emulsion formation, stability, and their applications

Pickering emulsions are increasingly preferred over typical surfactant-based emulsions due to several advantages, such as lower emulsifier usage, simplicity, biocompatibility, and safety. These types of emulsions are stabilized using solid particles, which produce a thick layer at the oil-water interface preventing droplets from aggregating. Starch nano-particles (SNPs) have received considerable attention as natural alternatives to synthetic stabilizers due to their unique properties. Physical formulation processes are currently preferred for SNP production since they are environmentally friendly procedures that do not require the use of chemical reagents. This review provides a thorough overview in a critical perspective of the physical processes to produce starch nano-particles used as Pickering emulsion stabilizers, fabricated by a 2-step process. Specifically, the reviewed physical approaches for nano-starch preparation include high hydrostatic pressure, high pressure homogenization, ultrasonication, milling and antisolvent precipitation. All the essential parameters used to evaluate the effectiveness of particles in stabilizing these systems are also presented in detail, including the hydrophobicity, size, and content of starch particles. Finally, this review provides the basis for future research focusing on physical nano-starch production, to ensure the widespread use of these natural stabilizers in the ever-evolving field of food technology.

Lyophilization for Formulation Optimization of Drug-Loaded Thermoresponsive Polyelectrolyte Complex Nanogels from Functionalized Hyaluronic Acid

The lyophilization of nanogels is practical not only for their long-term conservation but also for adjusting their concentration and dispersant type during reconstitution for different applications. However, lyophilization strategies must be adapted to each kind of nanoformulation in order to minimize aggregation after reconstitution. In this work, the effects of formulation aspects (i.e., charge ratio, polymer concentration, thermoresponsive grafts, polycation type, cryoprotectant type, and concentration) on particle integrity after lyophilization and reconstitution for different types of polyelectrolyte complex nanogels (PEC-NGs) from hyaluronic acid (HA) were investigated. The main objective was to find the best approach for freeze-drying thermoresponsive PEC-NGs from Jeffamine-M-2005-functionalized HA, which has recently been developed as a potential platform for drug delivery. It was found that freeze-drying PEC-NG suspensions prepared at a relatively low polymer concentration of 0.2 g.L−1 with 0.2% (m/v) trehalose as a cryoprotectant allow the homogeneous redispersion of PEC-NGs when concentrated at 1 g.L−1 upon reconstitution in PBS without important aggregation (i.e., average particle size remaining under 350 nm), which could be applied to concentrate curcumin (CUR)-loaded PEC-NGs for optimizing CUR content. The thermoresponsive release of CUR from such concentrated PEC-NGs was also reverified, which showed a minor effect of freeze-drying on the drug release profile.

Impact of formulation design and lyophilisation on the physicochemical characteristics of finasteride nanosystems

The fundamental purpose of this study was to develop a stable lyophilised finasteride nanosystem (FNS-NS) for topical delivery. The FNS-NS was fabricated using an ultrasonication technique. The impact of two different cryoprotectants on the physicochemical characteristics of FNS-NS before and after lyophilisation was thoroughly investigated. The lyophilised FNS-NS had spherical shape with particle size lied between 188.6 nm ± 4.4 and 298.7 nm ± 4.7, low PDI values (0.26 ± 0.02 to 0.32 ± 0.02) and zeta potential ranging from -38.3 to +53.3 mV. The confocal laser microscopy depicted a comparatively higher cellular internalisation achieved for undecorated FNS-NS with respect to its chitosan-decorated counterpart. The lyophilised FNS-NS was stable for 90 days at proper storage conditions. The FNS-NS with 15% trehalose had appropriate physicochemical attributes that could be a promising carrier for topical delivery to treat androgenic alopecia.

Application of cellulose- and chitosan-based edible coatings for quality and safety of deep-fried foods

Excessive oil uptake and formation of carcinogens, such as acrylamide (AA), heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs), during deep-frying are a potential threat for food quality and safety. Cellulose- and chitosan-based edible coatings have been widely applied to deep-fried foods for reduction of oil uptake because of their barrier property to limit oil ingress, and their apparent inhibition of AA formation. Cellulose- and chitosan-based edible coatings have low negative impacts on sensory attributes of fried foods and are low cost, nontoxic, and nonallergenic. They also show great potential for reducing HCAs and PAHs in fried foods. The incorporation of nanoparticles improves mechanical and barrier properties of cellulose and chitosan coatings, which may also contribute to reducing carcinogens derived from deep-frying. Considering the potential for positive health outcomes, cellulose- and chitosan-based edible coatings could be a valuable method for the food industry to improve the quality and safety of deep-fried foods.

Application of chitosan nanoparticles in quality and preservation of postharvest fruits and vegetables: A review

Chitosan is an interesting alternative material for packaging development due to its biodegradability. However, its poor mechanical properties and low permeability limit its actual applications. Chitosan nanoparticles (CHNPs) have emerged as a suitable solution to overcome these intrinsic limitations. In this review, all studies regarding the use of CHNPs to extend the shelf life and improve the quality of postharvest products are covered. The characteristics of CHNPs and their combinations with essential oils and metals, along with their effects on postharvest products, are compared and discussed throughout the manuscript. CHNPs enhanced postharvest antioxidant capacity, extended shelf life, increased nutritional quality, and promoted tolerance to chilling stress. Additionally, the CHNPs reduced the incidence of postharvest phytopathogens. In most instances, smaller CHNPs (<150 nm) conferred higher benefits than larger ones (>150 nm). This was likely a result of the greater plant tissue penetrability and surface area of the smaller CHNPs. The CHNPs were either applied after preparing an emulsion or incorporated into a film, with the latter often exhibiting greater antioxidant and antimicrobial activities. CHNPs were used to encapsulate essential oils, which could be released over time and may enhance the antioxidant and antimicrobial properties of the CHNPs. Even though most applications were performed after harvest, preharvest application had longer lasting effects.

Evaluation of chitosan salt properties in the production of AgNPs materials with antibacterial activity

In this study, water-soluble chitosan salts (chitosan amine sulfopropyl salts) were prepared from chitosan samples with different molecular weights and deacetylation degrees. These soluble-in-water polymer salts allowed us to produce, in an eco-friendly and facile method, silver nanoparticles (AgNPs) with better control on size and polydispersity, even at large silver concentrations than their corresponding chitosan sample. Chitosan salt-based materials (films and scaffolds) were analyzed in terms of antibacterial properties against Staphylococcus aureus ATCC23915 or Pseudomonas aeruginosa ATCC 27853. 3D scaffolds enhanced the effect of the chitosan-AgNPs combination compared to the equivalent films.

Biodegradable Polymeric Nanoparticles Loaded with Flavonoids: A Promising Therapy for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of disorders that cause chronic non-specific inflammation in the gastrointestinal (GI) tract, primarily affecting the ileum and colon. The incidence of IBD has risen sharply in recent years. Despite continuous research efforts over the past decades, the aetiology of IBD is still not fully understood and only a limited number of drugs are available for its treatment. Flavonoids, a ubiquitous class of natural chemicals found in plants, have been widely used in the prevention and treatment of IBD. However, their therapeutic efficacy is unsatisfactory due to poor solubility, instability, rapid metabolism, and rapid systemic elimination. With the development of nanomedicine, nanocarriers can efficiently encapsulate various flavonoids and subsequently form nanoparticles (NPs), which greatly improves the stability and bioavailability of flavonoids. Recently, progress has also been made in the methodology of biodegradable polymers that can be used to fabricate NPs. As a result, NPs can significantly enhance the preventive or therapeutic effects of flavonoids on IBD. In this review, we aim to evaluate the therapeutic effect of flavonoid NPs on IBD. Furthermore, we discuss possible challenges and future perspectives.

Chitosan-Based Nanoparticles as Effective Drug Delivery Systems-A review

Chitosan-based nanoparticles (chitosan-based nanocomposites; chitosan nanoparticles; ChNPs) are promising materials that are receiving a lot of attention in the last decades. ChNPs have great potential as nanocarriers. They are able to encapsulate drugs as well as active compounds and deliver them to a specific place in the body providing a controlled release. In the article, an overview has been made of the most frequently used preparation methods, and the developed applications in medicine. The presentation of the most important information concerning ChNPs, especially chitosan's properties in drug delivery systems (DDS), as well as the method of NPs production was quoted. Additionally, the specification and classification of the NPs' morphological features determined their application together with the methods of attaching drugs to NPs. The latest scientific reports of the DDS using ChNPs administered orally, through the eye, on the skin and transdermally were taken into account.

Whey Protein Isolate-Chitosan PolyElectrolyte Nanoparticles as a Drug Delivery System

Whey protein isolate (WPI), employed as a carrier for a wide range of bioactive substances, suffers from a lack of colloidal stability in physiological conditions. Herein, we developed innovative stabilized PolyElectrolyte Nanoparticles (PENs) obtained by two techniques: polyelectrolyte complexation of negatively charged WPI and positively charged chitosan (CS), and ionic gelation in the presence of polyanion tripolyphosphate (TPP). Therefore, the WPI-based core was coated with a CS-based shell and then stabilized by TPP at pH 8. The nanostructures were characterized by physiochemical methods, and their encapsulation efficiency and in vitro release were evaluated. The spherical NPs with an average size of 248.57 ± 5.00 nm and surface charge of +10.80 ± 0.43 mV demonstrated high encapsulation efficiency (92.79 ± 0.69) and sustained release of a positively charged chemotherapeutic agent such as doxorubicin (DOX). Z-average size and size distribution also presented negligible increases in size and aggregates during the three weeks. The results obtained confirm the effectiveness of the simultaneous application of these methods to improve the colloidal stability of PEN.

Development of a Halochromic, Antimicrobial, and Antioxidant Starch-Based Film Containing Phenolic Extract from Jaboticaba Peel

In this study, the antioxidant, antimicrobial, mechanical, optical, and barrier attributes of Solanum lycocarpum starch bio-based edible films incorporated with a phenolic extract from jaboticaba peel were investigated. Aiming to determine the effect of the polymers and the phenolic extract on the properties of the films, a three-factor simplex-lattice design was employed, and the formulation optimization was based on the produced films' antioxidant potential. The optimized formulation of the starch-PEJP film showed a reddish-pink color with no cracks or bubbles and 91% antioxidant activity against DPPH radical. The optimized starch-PEJP film showed good transparency properties and a potent UV-blocking action, presenting color variation as a function of the pH values. The optimized film was also considerably resistant and highly flexible, showing a water vapor permeability of 3.28 × 10-6 g m-1 h-1 Pa-1. The microbial permeation test and antimicrobial evaluation demonstrated that the optimized starch-PEJP film avoided microbial contamination and was potent in reducing the growth of Escherichia coli, Staphylococcus aureus, and Salmonella spp. In summary, the active starch-PEJP film showed great potential as an environmentally friendly and halochromic material, presenting antioxidant and antimicrobial properties and high UV-protecting activity.

Microencapsulation of Probiotics by Oil-in-Water Emulsification Technique Improves Cell Viability under Different Storage Conditions

Probiotics are associated with health benefits to the host. However, their application can be limited due to a decrease in cell viability during processing, storage, and passage through the gastrointestinal tract. Microencapsulation is a simple and efficient alternative to improve the physical protection and stability of probiotics. The present study aimed to produce and characterize alginate or gelatin-based microparticles containing Lactobacillus acidophilus NRRL B-4495 or Lactiplantibacillus plantarum NRRL B-4496 by oil-in-water (O/W) emulsification and to evaluate the stability under storage conditions. The results showed that L. acidophilus and L. plantarum encapsulated in gelatin (LAEG and LPEG) presented diameters of 26.08 ± 1.74 μm and 21.56 ± 4.17 μm and encapsulation efficiencies of 89.6 ± 4.2% and 81.1 ± 9.7%, respectively. However, those encapsulated in alginate (LAEA and LPEA) showed an encapsulation efficiency of <1.0%. Furthermore, LAEG was stable for 120 days of storage at 5 °C and 25 °C. Therefore, encapsulation in gelatin by O/W emulsification is a promising strategy for protecting and stabilizing probiotic bacteria, enabling future application in foods.

Synthesis of Chitosan Microparticles Encapsulating Bacterial Cell-Free Supernatants and Indole Acetic Acid, and Their Effects on Germination and Seedling Growth in Tomato (Solanum lycopersicum)

Encapsulation of biostimulant metabolites has gained popularity as it increases their shelf life and improves their absorption, being considered a good alternative for the manufacture of products that stimulate plant growth and fruit production. Cell-free supernatants (CFS) were obtained from nine indole-3-acetic acid (IAA) producing bacterial strains. Stenotrophomonas maltophilia (PT53T) produced the highest concentration of IAA (15.88 μg/mL) after 48 h of incubation. CFS from this strain, as well as an IAA standard were separately encapsulated in chitosan microparticles (CS-MP) using the ionic gelation method. The CS-MP were analyzed by Fourier transform infrared spectroscopy (FTIR), showing absorption bands at 1641, 1547, and 1218 cm-1, associated with the vibrations of the carbonyl C=O, the N-H amine, and the bond between chitosan (CHI) and sodium tripolyphosphate (TPP). The effects of unencapsulated CFS, encapsulated CFS (EN-CFS), and encapsulated IAA standard (EN-IAA) on germination and growth of seven-day-old tomato (Solanum lycopersicum) seedlings were studied. Results showed that both EN-CFS and EN-IAA significantly (p < 0.05) increased seed germination rates by 77.5 and 80.8%, respectively. Both CFS and EN-IAA produced the greatest increase in aerial part length and fresh weight with respect to the treatment-free test. Therefore, it was concluded that the application of EN-CFS or EN-IAA could be a good option to improve the germination and growth of tomato seedlings.

Progressive Application of Marine Biomaterials in Targeted Cancer Nanotherapeutics

The marine microenvironment harbors many unique species of organisms that produce a plethora of compounds that help mankind cure a wide range of diseases. The diversity of products from the ocean bed serves as potentially healing materials and inert vehicles carrying the drug of interest to the target site. Several composites still lay undiscovered under the blue canopy, which can provide treatment for untreated diseases that keep haunting the earth periodically. Cancer is one such disease that has been of interest to several eminent scientists worldwide due to the heterogenic complexity involved in the disease's pathophysiology. Due to extensive globalization and environmental changes, cancer has become a lifestyle disease continuously increasing exponentially in the current decade. This ailment requires a definite remedy that treats by causing minimal damage to the body's normal cells. The application of nanotechnology in medicine has opened up new avenues of research in targeted therapeutics due to their highly malleable characteristics. Marine waters contain an immense ionic environment that succors the production of distinct nanomaterials with exceptional character, yielding highly flexible molecules to modify, thus facilitating the engineering of targeted biomolecules. This review provides a short insight into an array of marine biomolecules that can be probed into cancer nanotherapeutics sparing healthy cells.

Heparosan-based self-assembled nanocarrier for zinc(II) phthalocyanine for use in photodynamic cancer therapy

Zinc(II) phthalocyanine (ZnPc) is a promising photosensitizer in photodynamic therapy (PDT) for melanoma treatment. However, the poor solubility of ZnPc limits its application. To overcome this limitation, heparosan (HP)-based nanoparticles were prepared by anchoring the l-lysine-linked α-linolenic acid branch to the carboxylic acid group to produce amphiphilic conjugates named heparosan with an l-lysine-linked α-linolenic acid branch (HLA). HLA conjugates could self-assemble into spherical nanoparticles in aqueous media and encapsulate ZnPc to form HLA-ZnPc nanoparticles. The cellular uptake of ZnPc could be improved by HLA carriers. These nanoparticles presented excellent photodynamic-mediated toxicity against mouse melanoma cells (B16) by markedly upregulating the intracellular reactive oxygen species (ROS) levels while showing no cytotoxicity to either B16 or normal cells (L02 and HK-2 cells) in the dark. Furthermore, HLA-ZnPc displayed excellent stability in both powder and Roswell Park Memorial Institute (RPMI) 1640 medium, indicating its promise for application in drug delivery and PDT. These results revealed a strategy for HP-based enhancement of ZnPc in PDT efficacy.

Polymeric Nanoparticles for Inhaled Vaccines

Many recent studies focus on the pulmonary delivery of vaccines as it is needle-free, safe, and effective. Inhaled vaccines enhance systemic and mucosal immunization but still faces many limitations that can be resolved using polymeric nanoparticles (PNPs). This review focuses on the use of properties of PNPs, specifically chitosan and PLGA to be used in the delivery of vaccines by inhalation. It also aims to highlight that PNPs have adjuvant properties by themselves that induce cellular and humeral immunogenicity. Further, different factors influence the behavior of PNP in vivo such as size, morphology, and charge are discussed. Finally, some of the primary challenges facing PNPs are reviewed including formulation instability, reproducibility, device-related factors, patient-related factors, and industrial-level scale-up. Herein, the most important variables of PNPs that shall be defined in any PNPs to be used for pulmonary delivery are defined. Further, this study focuses on the most popular polymers used for this purpose.

Novel Therapeutic Approach in PEGylated Chitosan Nanoparticles of Apigenin for the Treatment of Cancer via Oral Nanomedicine

The goal of this study was to optimize and formulate apigenin (APG)-loaded pegylated chitosan nanoparticles (PEGylated-CNPs) via ionic gelation techniques using the Box-Behnken design (BBD). Three individual variables, X₁(chitosan: TPP concentration), X₂ (PEG-400 concentration), and X₃ (sonication time), were investigated for their influence on response variables (Y₁-particle size (PS); Y₂-drug entrapment efficiency (DEE); and Y₃-zeta potential (ZP). The optimized formula of APG-PEGylated CNPs was picked from the statistical design and was then examined for physical, morphological, release characterization, anti-oxidant, and anti-tumor potential. The average PS, PDI, %DEE, and ZP were found to be 139.63 ± 5.67 nm, 0.296 ± 0.014, 79.55 ± 3.12%, and 24.68 ± 1.84 mV, respectively. The optimized APG formulation was chosen and reformulated based on the desirability function. Results of the observed and predicted values of responses through the BBD process were found to be nearly identical. The resulting APG-PEGylated CNPs were spherical and smooth, according to surface morphology studies. The release study revealed that PEGylated-CNPs exhibited biphasic release patterns distinguished by an initial burst release of APG only at early phases accompanied by a delayed release near 24 h. Furthermore, APG-PEGylated CNPs demonstrated statistically increased antioxidant activities and cytotoxicity against MCF-7 cells compared to pure APG. Based on the findings, it is possible to conclude that BBD was efficient in optimizing the PEGylated CNPs formulation and recognizing the impacts of formulation variables. In conclusion, the developed formulation has a significant potential for anticancer therapy.

Chitosan Nanoparticles: A Versatile Platform for Biomedical Applications

Chitosan is a biodegradable and biocompatible natural polymer that has been extensively explored in recent decades. The Food and Drug Administration has approved chitosan for wound treatment and nutritional use. Furthermore, chitosan has paved the way for advancements in different biomedical applications including as a nanocarrier and tissue-engineering scaffold. Its antibacterial, antioxidant, and haemostatic properties make it an excellent option for wound dressings. Because of its hydrophilic nature, chitosan is an ideal starting material for biocompatible and biodegradable hydrogels. To suit specific application demands, chitosan can be combined with fillers, such as hydroxyapatite, to modify the mechanical characteristics of pH-sensitive hydrogels. Furthermore, the cationic characteristics of chitosan have made it a popular choice for gene delivery and cancer therapy. Thus, the use of chitosan nanoparticles in developing novel drug delivery systems has received special attention. This review aims to provide an overview of chitosan-based nanoparticles, focusing on their versatile properties and different applications in biomedical sciences and engineering.

Pulmonary drug delivery applications of natural polysaccharide polymer derived nano/micro-carrier systems: A review

Respiratory distress syndrome and pneumothorax are the foremost causes of death as a result of the changing lifestyle and increasing air pollution. Numerous approaches have been studied for the pulmonary delivery of drugs, proteins as well as peptides using meso/nanoparticles, nanocrystals, and liposomes. These nano/microcarrier systems (NMCs) loaded with drug provide better systemic as well as local action. Furthermore, natural polysaccharide-based polymers such as chitosan (CS), alginate (AG), hyaluronic acid, dextran, and cellulose are highly used for the preparation of nanoparticles and delivery of the drug into the pulmonary tract due to their advantageous properties such as low toxicity, high hydrophobicity, supplementary mucociliary clearance, mucoadhesivity, and biological efficacy. These properties ease the delivery of drugs onto the targeted site. Herein, recent advances in the natural polymer-derived NMCs have been reviewed for their transport and mechanism of action into the bronchiolar region as well as the respiratory region. Various physicochemical properties such as surface charge, size of nanocarrier system, surface modifications, and toxicological effects of these nanocarriers in vitro and in vivo are elucidated as well. Furthermore, challenges faced for the preparation of a model NMCs for pulmonary drug delivery are also discoursed.