Development of chitosan–pullulan composite nanoparticles for nasal delivery of vaccines: optimisation and cellular studies

Antimicrobial peptides grafted onto the surface of N-acetylcysteine-chitosan nanoparticles can revitalize drugs against clinical isolates of Mycobacterium tuberculosis

Tuberculosis is caused by Mycobacterium tuberculosis (MTB) and is the leading cause of death from infectious diseases in the World. The search for new antituberculosis drugs is a high priority, since several drug-resistant TB-strains have emerged. Many nanotechnology strategies are being explored to repurpose or revive drugs. An interesting approach is to graft antimicrobial peptides (AMPs) to antibiotic-loaded nanoparticles. The objective of the present work was to determine the anti-MTB activity of rifampicin-loaded N-acetylcysteine-chitosan-based nanoparticles (NPs), conjugated with the AMP Ctx(Ile21)-Ha; against clinical isolates (multi- and extensively-drug resistant) and the H37Rv strain. The modified chitosan and drug-loaded NPs were characterized with respect to their physicochemical stability and their antimycobacterial profile, which showed potent inhibition (MIC values <0.977 μg/mL) by the latter. Furthermore, their accumulation within macrophages and cytotoxicity were determined. To understand the possible mechanisms of action, an in silico study of the peptide against MTB membrane receptors was performed. The results presented herein demonstrate that antibiotic-loaded NPs grafted with an AMP can be a powerful tool for revitalizing drugs against multidrug-resistant M. tuberculosis strains, by launching multiple attacks against MTB. This approach could potentially serve as a novel treatment strategy for various long-term diseases requiring extended treatment periods.

Etoricoxib nanostructured lipid carriers attenuate inflammation by modulating Cyclooxygenase-2 signaling and activation of nuclear factor-κB-p65 pathways in radiation-induced acute cardiotoxicity in rats

The current investigation aimed to explore the potential of etoricoxib nanostructured lipid carriers (ET-NLCs) as an anti-inflammatory drug in radiation-exposed rats, with a focus on assessing its efficacy in reducing inflammation while minimizing cardiac toxicity compared to conventional etoricoxib (ET) treatment. The ET-NLCs were prepared by the low-temperature melt emulsification solidification technique. Various techniques were employed to characterize the NLCs. Rats were exposed to gamma-irradiation (6 Gy) to induce cardiac inflammation and injury, followed by oral administration of ET or ET-NLCs (10 mg/kg b.w.) for 14 consecutive days. Results demonstrated a significant increase in the levels of malondialdehyde (MDA), cyclooxygenase-2 (COX-2), nuclear factor kappa-B p65 (NF-κB-p65), and poly ADP-ribose polymerase (PARP-1) in the heart tissues of gamma-irradiated rats compared to the control group. This increase was accompanied by a reduction in the activity of antioxidant enzymes. However, treatment with ET and ET-NLCs exhibited a positive impact on these levels. Interestingly, the efficacy of ET-NLCs in mitigating radiation-induced inflammation in heart tissue was found to be superior to that of ET. In conclusion, the study suggests that the utilization of NLCs as a drug delivery system for ET may not only enhance its therapeutic efficacy but also help reduce the cardiovascular risks associated with ET, specifically focused on individuals who had been exposed to gamma radiation. These findings open new avenues for further research in the development of effective and safer therapeutic strategies for managing inflammatory diseases and their impact on cardiovascular health.

Production and applications of pullulan from lignocellulosic biomass: Challenges and perspectives

Pullulan is an exopolysaccharide produced by Aureobasidium pullulans, with interesting characteristics which lead to its application in industries such as pharmaceuticals, cosmetics, food, and others. To reduce production costs for industrial applications, cheaper raw materials such as lignocellulosic biomass can be utilized as a carbon and nutrient source for the microbial process. In this study, a comprehensive and critical review was conducted, encompassing the pullulan production process and the key influential variables. The main properties of the biopolymer were presented, and different applications were discussed. Subsequently, the utilization of lignocellulosics for pullulan production within the framework of a biorefinery concept was explored, considering the main published works that deal with materials such as sugarcane bagasse, rice husk, corn straw, and corn cob. Next, the main challenges and future prospects in this research area were highlighted, indicating the key strategies to favor the industrial production of pullulan from lignocellulosic biomasses.

Chitosan-based buccal mucoadhesive patches to enhance the systemic bioavailability of tizanidine

Tizanidine hydrochloride (TZN) is a muscle relaxant used to treat a variety of disorders such as painful muscle spasms and chronic spasticity. TZN has low oral bioavailability due to extensive first-pass metabolism and is used orally at a dose of 6-24 mg per day. In the present study, buccal patches were prepared by solvent casting method using chitosan glutamate (Chi-Glu) and novel chitosan azelate (Chi-Aze) which was synthesised in-house for the first time, to enhance the bioavailability of TZN by bypassing first-pass metabolism. The characterisation, mucoadhesion and drug release studies were performed. Chi-Aze patches retained their integrity longer in the buccal medium and showed higher ex vivo drug permeability compared to that prepared with Chi-Glu. In vivo studies revealed that buccal formulation fabricated with Chi-Aze (3%) showed approx 3 times more bioavailability than the orally administered commercial product. Results of the studies indicate that Chi-Aze, prepared by conjugation of chitosan and a fatty acid, the patch formulation is a promising buccal mucoadhesive system due to the physical stability in buccal medium, the good mucoadhesiveness and the high TZN bioavailability. Moreover, Chi-Aze patch might be an alternative to oral formulations of TZN to reduce the dose and frequency of drug administration.

Chitosan Hydrogel as Tissue Engineering Scaffolds for Vascular Regeneration Applications

Chitosan hydrogels have a wide range of applications in tissue engineering scaffolds, mainly due to the advantages of their chemical and physical properties. This review focuses on the application of chitosan hydrogels in tissue engineering scaffolds for vascular regeneration. We have mainly introduced these following aspects: advantages and progress of chitosan hydrogels in vascular regeneration hydrogels and the modification of chitosan hydrogels to improve the application in vascular regeneration. Finally, this paper discusses the prospects of chitosan hydrogels for vascular regeneration.

Immunomodulation in age-related disorders and nanotechnology interventions

Recently, the aging population has increased exponentially around the globe bringing more challenges to improve quality of life in those populations while reducing the economic burden on healthcare systems. Aging is associated with changes in the immune system culminating in detrimental effects such as immune dysfunction, immunosenescence, and chronic inflammation. Age-related decline of immune functions is associated with various pathologies including cardiovascular, autoimmune, neurodegenerative, and infectious diseases to name a few. Conventional treatment addresses the onset of age-related diseases by early detection of risk factors, administration of vaccines as preventive care, immunomodulatory treatment, and other dietary supplements. However, these approaches often come with systemic side-effects, low bioavailability of therapeutic agents, and poor outcomes seen in the elderly. Recent innovations in nanotechnology have led to the development of novel biomaterials/nanomaterials, which explore targeted drug delivery and immunomodulatory interactions in vivo. Current nanotechnology-based immunomodulatory approaches that have the potential to be used as therapeutic interventions for some prominent age-related diseases are discussed here. Finally, we explore challenges and future aspects of nanotechnology in the treatments of age-related disorders to improve quality of life in the elderly. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Emerging Trends in Pullulan-Based Antimicrobial Systems for Various Applications

Global reports on multidrug resistance (MDR) and life-threatening pathogens such as SARS-CoV-2 and Candida cruris have stimulated researchers to explore new antimicrobials that are eco-friendly and economically viable. In this context, biodegradable polymers such as nisin, chitin, and pullulan play an important role in solving the problem. Pullulan is an important edible, biocompatible, water-soluble polymer secreted by Aureobasidium pullulans that occurs ubiquitously. It consists of maltotriose units linked with α-1,6 glycosidic bonds and is classed as Generally Regarded as Safe (GRAS) by the Food and Drug Administration (FDA) in the USA. Pullulan is known for its antibacterial, antifungal, antiviral, and antitumor activities when incorporated with other additives such as antibiotics, drugs, nanoparticles, and so on. Considering the importance of its antimicrobial activities, this polymer can be used as a potential antimicrobial agent against various pathogenic microorganisms including the multidrug-resistant (MDR) pathogens. Moreover, pullulan has ability to synthesize biogenic silver nanoparticles (AgNPs), which are remarkably efficacious against pathogenic microbes. The pullulan-based nanocomposites can be applied for wound healing, food packaging, and also enhancing the shelf-life of fruits and vegetables. In this review, we have discussed biosynthesis of pullulan and its role as antibacterial, antiviral, and antifungal agent. Pullulan-based films impregnated with different antimicrobials such as AgNPs, chitosan, essential oils, and so on, forming nanocomposites have also been discussed as natural alternatives to combat the problems posed by pathogens.

Polysaccharide nanoparticles: from fabrication to applications

The present review highlights the developments in polysaccharide nanoparticles with a particular focus on applications in biomedicine, cosmetics and food.

Mushrooms and immunity

In the wide field of nutraceuticals, the effects of mushrooms on immunity, cancer and including autoimmunity have been proposed for centuries but in recent years a growing interest has led scientists to elucidate which specific compounds have bioactive properties and through which mechanisms. Glucans and specific proteins are responsible for most of the biological effects of mushrooms, particularly in terms of immunomodulatory and anti-tumor results. Proteins with bioactive effects include lectins, fungal immunomodulatory proteins (FIPs), ribosome inactivating proteins (RIPs), ribonucleases, laccases, among others. At the present status of knowledge, numerous studies have been performed on cell lines and murine models while only a few clinical trials have been conducted. As in most cases of dietary components, the multitude of variables implicated in the final effect and an inadequate standardization are expected to affect the observed differences, thus making the available evidence insufficient to justify the treatment of human diseases with mushrooms extracts. We will herein provide a comprehensive review and critically discussion the biochemical changes induced by different mushroom compounds as observed in in vitro studies, particularly on macrophages, dendritic cells, T cells, and NK cells, compared to in vivo and human studies. Additional effects are represented by lipids which constitute a minor part of mushrooms but may have a role in reducing serum cholesterol levels or phenols acting as antioxidant and reducing agents. Human studies provide a minority of available data, as well illustrated by a placebo-controlled study of athletes treated with β-glucan from Pleurotus ostreatus. Variables influencing study outcomes include different mushrooms strains, growing conditions, developmental stage, part of mushroom used, extraction method, and storage conditions. We foresee that future rigorous research will be needed to determine the potential of mushroom compounds for human health to reproduce the effects of some compounds such as lentinan which a metaanalysis demonstrated to increase the efficacy of chemotherapy in the treatment of lung cancer and in the improvement of the patients quality of life.

Oxytocin-loaded sustained-release hydrogel graft provides accelerated bone formation: An experimental rat study

Restoration of the lost bone volume is one of the most deliberate issues in dentistry. Sustained-release microspherical oxytocin hormone in a poloxamer hydrogel scaffold combined with a mixture of β-tricalcium phosphate and hydroxyapatite (CP) may serve as a suitable bone graft. The aim of this study was to design and test a novel thermosensitive hydrogel graft incorporating oxytocin-loaded poly(d, l-lactide-co-glycolide) (PLGA) sustained-release microspheres and CP. Thermosensitive poloxamer hydrogel containing CP (HCP graft) was prepared as a base and combined with hollow microspheres (HCPM) and oxytocin-loaded microspheres (HCPOM). Eighty Wistar rats were used for testing the grafts and a control group in 8-mm-diameter critical-sized calvarial defects (CSD); (n = 20). Bone healing at the 4th and 8th weeks was evaluated by histological, histomorphometric, and radiological (micro-computed tomography [µCT]) analyses. The results were analyzed by two-way analysis of variance (P < .05). Oxytocin-loaded PLGA microspheres prepared by the solvent displacement method yielded a high encapsulation efficiency of 89.5% and a slow drug release. Incorporation of the microspheres into the hydrogel graft slowed the release rate down and the release completed within 32 days. HCPOM revealed the highest new bone formation (26.45% ± 6.65% and 30.76% ± 4.37% at the 4th and 8th weeks, respectively; P < .0001) while HCPM and HCP groups revealed a bone formation of around 10% (P > .05). µCT findings of HCPOM group showed the highest mean bone mineral density values (42.21 ± 5.14 and 46.94 ± 3.30 g/cm³ for the 4th and 8th weeks, respectively; P < .0027). The proposed oxytocin-loaded sustained-release PLGA microspheres containing thermosensitive hydrogel graft (HCPOM) provide an accelerated bone regeneration in the rat calvaria.

Design of an amphiphilic hyperbranched core/shell-type polymeric nanocarrier platform for drug delivery

An amphiphilic core/shell-type polymer-based drug carrier system (HPAE- PCL-b -MPEG), composed of hyperbranched poly(aminoester)-based polymer (HPAE) as the core building block and poly(ethylene glycol)-b - poly(ε-caprolactone) diblock polymers (MPEG-b -PCL) as the shell building block, was designed. The synthesized polymers were characterized with FTIR, 1 H NMR, 13 C NMR, and GPC analysis. Monodisperse HPAE-PCL-b - MPEG nanoparticles with dimensions of < 200 nm and polydispersity index of < 0.5 were prepared by nanoprecipitation method and characterized with SEM, particle size, and zeta potential analysis. 5-Fluorouracil was encapsulated within HPAE-PCL-b -MPEG nanoparticles. In vitro drug release profiles and cytotoxicity of blank and 5-fluorouracil-loaded nanoparticles were examined against the human colon cancer HCT116 cell line. All results suggest that HPAE-PCL-b - MPEG nanoparticles offer an alternative and effective drug nanocarrier system for drug delivery applications.

β-glucan as a new tool in vaccine development

Vaccination constitutes one of the major breakthroughs in human medicine. At the same time, development of more immunogenic vaccine alternatives to using aluminium-based adjuvants is one of the most important phases of vaccination development. Among different sources of carbohydrate polymers, including plants, microbes and synthetic sources tested, glucans were found to be the most promising vaccine adjuvant, as they alone stimulate various immune reactions including antibody production without any negative side effects. The use of glucan particles as a delivery system is a viable option based on the documented efficient antigen loading and receptor-targeted uptake in antigen-presenting cells. In addition to particles, soluble glucans can be used as novel hydrogels or as direct immunocyte-targeting delivery systems employing novel complexes with oligodeoxynucleotides. This review focuses on recent advances in glucan-based vaccine development from glucan-based conjugates to a glucan-based delivery and adjuvant platform.

The efficacy of sustained-release chitosan microspheres containing recombinant human parathyroid hormone on MRONJ

Treatment of patients with bisphosphonate usage is a significant concern for oral surgeons because it interferes with jaw bone turnover and regeneration. In case of adverse effects manifesting related to bisphosphonate use, oral surgeons are usually treating and keep the patient's symptoms under control. In this study, we aimed to investigate a new treatment protocol for medication-related osteonecrosis of the jaw (MRONJ). This treatment protocol consisted of administering human parathyroid hormone (hPTH) loaded chitosan microspheres which were prepared by ionotropic gelation method or/and the prepared microspheres were suspended in a poloxamer gel. After in-vitro optimization studies, the efficacy of the chosen formulations was evaluated in-vivo studies. Zoledronic acid was administered daily to forty-eight adult female Sprague-Dawley rats, divided into four experimental groups, at a daily concentration of 0.11 mg/kg over three weeks to induce the MRONJ model. At the end of this period, maxillary left molar teeth were extracted. In the first group, the subjects received no treatment. In the negative control group, poloxamer hydrogel containing empty microspheres were immediately applied to the soft tissues surrounding the extraction socket. The treatment group-1 was treated with local injections of poloxamer hydrogel containing hPTH. The treatment group-2 was treated with a single local injection of poloxamer hydrogel containing hPTH-loaded chitosan microspheres. Both treatment groups received a total of 7 µg of hPTH at the end of the treatment protocol. Our study demonstrates successful attenuation of MRONJ through a local drug delivery system combined with hPTH, as opposed to previously attempted treatment strategies.

Modified chitosan-based nanoadjuvants enhance immunogenicity of protein antigens after mucosal vaccination

Nasal vaccination is considered to be an effective and convenient way of increasing immune responses both systemically and locally. Although various nanovaccine carriers have been introduced as potential immune adjuvants, further improvements are still needed before they can be taken to clinical usage. Chitosan-based nanovaccine carriers are one of the most widely studiedadjuvants, owing to the abilityof chitosan toopen tight junctions between nasal epithelial cells and enhance particle uptake as well as its inherent immune activating role. In present study, bovine serum albumin (BSA) loaded nanoparticles were prepared using novel aminated (aChi) and aminated plus thiolated chitosan (atChi) polymers, to further enhance mucoadhesiveness and adjuvanticity of the vaccine system by improving electrostatic interactions of polymers with negatively charged glycoproteins. Nanocarriers with optimum size and surface charge, high encapsulation efficiency of model antigen and good stability were developed. Negligible toxicity was observed in Calu-3 and A549 cell lines. In vivo studies, revealed high levels of systemic antibodies (IgG, IgG₁ and IgG_2a) throughout the study and presence of sIgA in vaginal washes showed that common mucosal system was successfully stimulated. Cytokine levels indicated a mixed Th1/Th2 immune response. A shift towards cellular immune responses was observed after nasal immunisation with antigen loaded nanoparticle formulations. These nanoparticles exhibit great potential for nasal application of vaccines.

Glucan and Mannan-Two Peas in a Pod

In recent decades, various polysaccharides isolated from algae, mushrooms, yeast, and higher plants have attracted serious attention in the area of nutrition and medicine. The reasons include their low toxicity, rare negative side effects, relatively low price, and broad spectrum of therapeutic actions. The two most and best-studied polysaccharides are mannan and glucan. This review focused on their biological properties.

Nanoparticles for Immune Stimulation Against Infection, Cancer, and Autoimmunity

Vaccination using nanocarrier-based delivery systems has recently emerged as a promising approach for meeting the continued challenge posed by infectious diseases and cancer. A diverse portfolio of nanocarriers of various sizes, compositions, and physical parameters have now been developed, and this diversity provides an opportunity for the rational design of vaccines that can mediate targeted delivery of various antigens and adjuvants or immune regulatory agents in ways unachievable with classical vaccination approaches. This flexibility allows control over the characteristics of vaccine-elicited immune responses such that they can be tailored to be effective in circumstances where classical vaccines have failed. Furthermore, the utility of nanocarrier-based immune modulation extends to the treatment of autoimmune disease where precisely targeted inhibition of immune responses is desirable. Clearly, the selection of appropriate nanocarriers, antigens, adjuvants, and other components underpins the efficacy of these nanoimmune interventions. Herein, we provide an overview of currently available nanocarriers of various types and their physical and pharmacological properties with the goal of providing a resource for researchers exploring nanomaterial-based approaches for immune modulation and identify some information gaps and unexplored questions to help guide future investigation.

Overviews on the cellular uptake mechanism of polysaccharide colloidal nanoparticles

Nanoparticulate drug/gene carriers have gained much attention in the past decades because of their versatile and tunable properties. However, efficacy of the therapeutic agents can be further enhanced using naturally occurring materials-based nanoparticles. Polysaccharides are an emerging class of biopolymers; therefore, they are generally considered to be safe, non-toxic, biocompatible and biodegradable. Considering that the target of nanoparticle-based therapeutic strategies is localization of biomedical agents in subcellular compartments, a detailed understanding of the cellular mechanism involved in the uptake of polysaccharide-based nanoparticles is essential for safe and efficient therapeutic applications. Uptake of the nanoparticles by the cellular systems occurs with a process known as endocytosis and is influenced by the physicochemical characteristics of nanoparticles such as size, shape and surface chemistry as well as the employed experimental conditions. In this study, we highlight the main endocytosis mechanisms responsible for the cellular uptake of polysaccharide nanoparticles containing drug/gene.

Nasal vaccination with poly(β-amino ester)-poly(d,l-lactide-co-glycolide) hybrid nanoparticles

Mucosal vaccination stimulates both mucosal and systemic immunity. However, mucosal applications of vaccine antigens in their free form generally result in poor systemic immune responses and need adjuvantation. In this study, bovine serum albumin loaded, new hybridised poly(β-amino ester)-poly(d,l-lactide-co-glycolide) nanoparticles were prepared by double emulsion-solvent evaporation method, characterised and evaluated in vivo as nasal vaccine carriers. Cationic spherical particles with a mean size of 240nm, good physical stability and high encapsulation efficiency were obtained. Protein structure was not affected throughout preparation and minimal toxicity was shown in Calu-3 and A549 cells. Nasal vaccination with these nanoparticles revealed markedly higher humoral immune responses compared with free antigen following intranasal and subcutaneous immunisation. Mucosal immune response was also stimulated and cytokine titres indicated that Th1 and Th2 pathways were successfully activated. This study shows that the formulated hybrid nanoparticles can be a promising carrier for nasal immunisation of poor antigenic proteins.

Recent developments in nanocarrier-aided mucosal vaccination

To date, most of the licensed vaccines for mucosal delivery are based on live-attenuated viruses which carry the risk of regaining their pathogenicity. Therefore, the development of efficient nonviral vectors allowing the induction of potent humoral and cell-mediated immunity is regarded as an imperative scientific challenge as well as a commercial breakthrough for the pharma industries. For a successful translation to the clinic, such nanocarriers should protect the antigens from mucosal enzymes, facilitate antigen uptake by microfold cells and allow the copresentation of robust, safe for human use, mucosal adjuvants to antigen-presenting cells. Finally, the developed formulations should exhibit accuracy regarding the administered dose, a major drawback of mucosal vaccines in comparison with parenteral ones.

BCG-loaded chitosan microparticles: interaction with macrophages and preliminary in vivo studies

The aim of this study was to develop a novel BCG-loaded chitosan vaccine with high association efficiency which can afford efficient interaction with APC and elicit local and Th1-type-specific immune response after intranasal administration. Chitosan-suspended BCG and BCG-loaded chitosan-alginate microparticles were prepared by ionotropic gelation. Interaction with APC was evaluated by fluorescence microscopy using rBCG-GFP. Specific immune responses were evaluated following intranasal immunisation of mice. Cellular uptake was approximately two-fold higher for chitosan-suspended BCG. A single dose of BCG-loaded microparticles or chitosan-suspended BCG by intranasal route improved Th1-type response compared with subcutaneous BCG. Chitosan-suspended BCG originated the highest mucosal response in the lungs by intranasal route. These positive results indicate that the proposed approach of whole live BCG microencapsulation in chitosan-alginate for intranasal immunisation was successful in allowing efficient interaction with APC, while improving the cellular immune response, which is of interest for local immunisation against tuberculosis.