Chitin and chitosan as tools to combat COVID-19: A triple approach

Applications and advancements of polysaccharide-based nanostructures for enhanced drug delivery

Growing demand for highly effective, site-specific delivery of pharmaceuticals and nutraceuticals using nano-sized carriers has prompted increased scrutiny of carrier biocompatibility and biodegradability. To address these concerns, biodegradable natural polymers have emerged as a transformative domain, offering non-toxic, precisely targetable carriers capable of finely modulating cargo pharmacokinetics while generating innocuous decomposition by-products. This comprehensive review illuminates the emergence of polysaccharide-based nanoparticulate drug delivery systems. These systems establish an interactive interface between drug and targeted organs, guided by strategic modifications to polysaccharide backbones, which facilitate the creation of morphologically, constitutionally, and characteristically vibrant nanostructures through various fabrication routes, underpinning their pivotal role in biomedical applications. Advancements crucial to enhancing polysaccharide-based drug delivery, such as surface modifications and bioinspired modifications for enhanced targeting, and stimuli-responsive release, strategies to overcome biological barriers, enhance tumor penetration, and optimize therapeutic outcomes are highlighted. This review also examines some potent challenges, and the contemporary way out of them, and discusses future perspectives in the field.

Recent Applications of Chitosan and Its Derivatives in Antibacterial, Anticancer, Wound Healing, and Tissue Engineering Fields

Chitosan, a versatile biopolymer derived from chitin, has garnered significant attention in various biomedical applications due to its unique properties, such as biocompatibility, biodegradability, and mucoadhesiveness. This review provides an overview of the diverse applications of chitosan and its derivatives in the antibacterial, anticancer, wound healing, and tissue engineering fields. In antibacterial applications, chitosan exhibits potent antimicrobial properties by disrupting microbial membranes and DNA, making it a promising natural preservative and agent against bacterial infections. Its role in cancer therapy involves the development of chitosan-based nanocarriers for targeted drug delivery, enhancing therapeutic efficacy while minimising side effects. Chitosan also plays a crucial role in wound healing by promoting cell proliferation, angiogenesis, and regulating inflammatory responses. Additionally, chitosan serves as a multifunctional scaffold in tissue engineering, facilitating the regeneration of diverse tissues such as cartilage, bone, and neural tissue by promoting cell adhesion and proliferation. The extensive range of applications for chitosan in pharmaceutical and biomedical sciences is not only highlighted by the comprehensive scope of this review, but it also establishes it as a fundamental component for forthcoming research in biomedicine.

Preparation and characterization of curdlan-chitosan conjugate nanoparticles as mucosal adjuvants for intranasal influenza H1N1 subunit vaccine

Intranasal vaccination offers crucial protection against influenza virus pandemics. However, antigens, especially subunit antigens, often fail to induce effective immune responses without the help of immune adjuvants. Our research has demonstrated that a polyelectrolyte complex, composed of curdlan sulfate/O-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (CS/O-HTCC), effectively triggers both mucosal and systemic immune responses when administrated intranasal. In this study, stable nanoparticles formed by curdlan-O-HTCC conjugate (CO NP) were prepared and characterized. Furthermore, the efficacy of CO NP was evaluated as a mucosal adjuvant in an intranasal influenza H1N1 subunit vaccine. The results revealed that CO NP exhibits uniform and spherical morphology, with a size of 190.53 ± 4.22 nm, and notably, it remains stable in PBS at 4 °C for up to 6 weeks. Biological evaluation demonstrated that CO NP stimulates the activation of antigen-presenting cells (APCs), including macrophages and dendritic cells (DCs), both in vitro and in vivo. Furthermore, intranasal administration of CO NP effectively elicits cellular and humoral immune responses, notably enhancing mucosal immunity. Thus, CO NP emerges as a promising mucosal adjuvant for influenza subunit vaccines.

Phospho-Chitooligosaccharides below 1 kDa Inhibit HIV-1 Entry In Vitro

Despite present antiviral agents that can effectively work against HIV-1 replication, side effects and drug resistance have pushed researchers toward novel approaches. In this context, there is a continued focus on discovering new and more effective antiviral compounds, particularly those that have a natural origin. Polysaccharides are known for their numerous bioactivities, including inhibiting HIV-1 infection and replication. In the present study, phosphorylated chitosan oligosaccharides (PCOSs) were evaluated for their anti-HIV-1 potential in vitro. Treatment with PCOSs effectively protected cells from HIV-1-induced lytic effects and suppressed the production of HIV-1 p24 protein. In addition, results show that PCOSs lost their protective effect upon post-infection treatment. According to the results of ELISA, PCOSs notably disrupted the binding of HIV-1 gp120 protein to T cell surface receptor CD4, which is required for HIV-1 entry. Overall, the results point out that PCOSs might prevent HIV-1 infection at the entry stage, possibly via blocking the viral entry through disruption of virus-cell fusion. Nevertheless, the current results only present the potential of PCOSs, and further studies to elucidate its action mechanism in detail are needed to employ phosphorylation of COSs as a method to develop novel antiviral agents.

Immunomodulatory activities and biomedical applications of melittin and its recent advances

Melittin (MLT), a peptide containing 26 amino acids, is a key constituent of bee venom. It comprises ∼40%-60% of the venom's dry weight and is the main pricing index for bee venom, being the causative factor of pain. The unique properties of MLT extracted from bee venom have made it a very valuable active ingredient in the pharmaceutical industry as this cationic and amphipathic peptide has propitious effects on human health in diverse biological processes. It has the ability to strongly impact the membranes of cells and display hemolytic activity with anticancer characteristics. However, the clinical application of MLT has been limited by its severe hemolytic activity, which poses a challenge for therapeutic use. By employing more efficient mechanisms, such as modifying the MLT sequence, genetic engineering, and nano-delivery systems, it is anticipated that the limitations posed by MLT can be overcome, thereby enabling its wider application in therapeutic contexts. This review has outlined recent advancements in MLT's nano-delivery systems and genetically engineered cells expressing MLT and provided an overview of where the MLTMLT's platforms are and where they will go in the future with the challenges ahead. The focus is on exploring how these approaches can overcome the limitations associated with MLT's hemolytic activity and improve its selectivity and efficacy in targeting cancer cells. These advancements hold promise for the creation of innovative and enhanced therapeutic approaches based on MLT for the treatment of cancer.

Progress in Treatment and Diagnostics of Infectious Disease with Polymers

In this era of advanced technology and innovation, infectious diseases still cause significant morbidity and mortality, which need to be addressed. Despite overwhelming success in the development of vaccines, transmittable diseases such as tuberculosis and AIDS remain unprotected, and the treatment is challenging due to frequent mutations of the pathogens. Formulations of new or existing drugs with polymeric materials have been explored as a promising new approach. Variations in shape, size, surface charge, internal morphology, and functionalization position polymer particles as a revolutionary material in healthcare. Here, an overview is provided of major diseases along with statistics on infection and death rates, focusing on polymer-based treatments and modes of action. Key issues are discussed in this review pertaining to current challenges and future perspectives.

Recent advances in chitosan-based materials; The synthesis, modifications and biomedical applications

The attention to polymer-based biomaterials, for instance, chitosan and its derivatives, as well as the techniques for using them in numerous scientific domains, is continuously rising. Chitosan is a decomposable naturally occurring polymeric material that is mostly obtained from seafood waste. Because of its special ecofriendly, biocompatible, non- toxic nature as well as antimicrobial properties, chitosan-based materials have received a lot of interest in the field of biomedical applications. The reactivity of chitosan is mainly because of the amino and hydroxyl groups in its composition, which makes it further fascinating for various uses, including biosensing, textile finishing, antimicrobial wound dressing, tissue engineering, bioimaging, gene, DNA and drug delivery and as a coating material for medical implants. This study is an overview of the different types of chitosan-based materials which now a days have been fabricated by applying different techniques and modifications that include etherification, esterification, crosslinking, graft copolymerization and o-acetylation etc. for hydroxyl groups' processes and acetylation, quaternization, Schiff's base reaction, and grafting for amino groups' reactions. Furthermore, this overview summarizes the literature from recent years related to the important applications of chitosan-based materials (i.e., thin films, nanocomposites or nanoparticles, sponges and hydrogels) in different biomedical applications.

The Importance of Chitosan Coatings in Dentistry

A Chitosan is a copolymer of N-acetyl-D-glucose amine and D-glucose amine that can be easily produced. It is a polymer that is widely utilized to create nanoparticles (NPs) with specific properties for applications in a wide range of human activities. Chitosan is a substance with excellent prospects due to its antibacterial, anti-inflammatory, antifungal, haemostatic, analgesic, mucoadhesive, and osseointegrative qualities, as well as its superior film-forming capacity. Chitosan nanoparticles (NPs) serve a variety of functions in the pharmaceutical and medical fields, including dentistry. According to recent research, chitosan and its derivatives can be embedded in materials for dental adhesives, barrier membranes, bone replacement, tissue regeneration, and antibacterial agents to improve the management of oral diseases. This narrative review aims to discuss the development of chitosan-containing materials for dental and implant engineering applications, as well as the challenges and future potential. For this purpose, the PubMed database (Medline) was utilised to search for publications published less than 10 years ago. The keywords used were "chitosan coating" and "dentistry". After carefully selecting according to these keywords, 23 articles were studied. The review concluded that chitosan is a biocompatible and bioactive material with many benefits in surgery, restorative dentistry, endodontics, prosthetics, orthodontics, and disinfection. Furthermore, despite the fact that it is a highly significant and promising coating, there is still a demand for various types of coatings. Chitosan is a semi-synthetic polysaccharide that has many medical applications because of its antimicrobial properties. This article aims to review the role of chitosan in dental implantology.

Addressing the resurgence of global monkeypox (Mpox) through advanced drug delivery platforms

Monkeypox (Mpox) is a transmissible infection induced by the Monkeypox virus (a double-stranded DNA virus), recognised under the family orthopoxvirus genus. Monkeypox, like endemic diseases, is a substantial concern worldwide; thus, comprehending the pathogenesis and mutagenesis of amino acids is indispensable to combat the infection. According to the World Health Organization's report, about 89 thousand cases with 160 mortalities have been reported from 114 countries worldwide. The conventional orthopoxvirus vaccines developed on live attenuated viruses exempted any clinical validation from combating monkeypox due to inadequate immunogenicity, toxicity, instability, and multiple doses. Therefore, novel drug delivery systems come into the conception with high biological and mechanical characteristics to address the resurgence of Global Monkeypox. The edges of metallic biomaterials, novel molecules, and vaccine development in targeted therapy increase the modulation of the immune response and blockage of host-virus interaction, with enhanced stability for the antigens. Thus, this review strives to comprehend the viral cell pathogenesis concerning amino acid mutagenesis and current epidemiological standards of the Monkeypox disease across the globe. Furthermore, the review also recapitulates the various clinical challenges, current therapies, and progressive nanomedicine utilisation in the Monkeypox outbreak reinforced by various clinical trial reports. The contemporary challenges of novel drug delivery systems in Monkeypox treatment cannot be overlooked, and thus, authors have outlined the future strategies to develop successful nanomedicine to combat monkeypox. Future pandemics are inevitable but can be satisfactorily handled if we comprehend the crises, innovate, and develop cutting-edge technologies, especially by delving into frontiers like nanotechnology.

Inhalable chitosan-based hydrogel as a mucosal adjuvant for hydroxychloroquine in the treatment for SARS-CoV-2 infection in a hamster model

BACKGROUND

Effective therapy for COVID-19 remains limited. Hydroxychloroquine (HCQ) has been considered, but safety and efficacy concerns remain. Chitosan exhibits antiviral and immunomodulatory effects, yet how the combination of HCQ and chitosan performs in treating COVID-19 is unknown.

METHODS

Male Syrian hamsters were inoculated intranasally with standardized stocks of the SARS-CoV-2 virus. Hamsters were allocated to saline (PBS), chitosan oligosaccharide (COS), HCQ, or COS + HCQ groups and received corresponding drugs. On days 1, 7, and 14 post-infection, two animals from each group were euthanized for sample collection. Viral loads were measured in lung homogenates. Biochemistry markers, cytokines, and immunoglobulins were analyzed from hamster sera. HCQ concentrations were compared between the blood, bronchoalveolar lavage, and lung tissues. All groups underwent histopathology exams of the lungs. Additional hamsters were treated with the same drugs to assess for toxicities to the heart and liver.

RESULTS

Among all groups, viral loads in the COS + HCQ group were the lowest by day 8. The COS + HCQ group produced the highest interleukin (IL)-6 levels on day 4, and the highest IL-10, IgA and IgG levels on day 8. HCQ concentrations were higher in the COS + HCQ group's lungs than the HCQ group, despite having received half the dose of HCQ. Histopathology demonstrated earlier inflammation resolution and swifter viral clearance in the COS + HCQ group. There was no evidence of cardiac or hepatic injury in hamsters that received HCQ.

CONCLUSION

In hamsters infected with the SARS-CoV-2 virus, the combination of intranasal COS and HCQ was associated with increased HCQ absorption in the lungs, more effective immune responses, without increasing the risk of hepatic or cardiac injuries.

Advancements in Chitosan-Based Nanoparticles for Pulmonary Drug Delivery

The evolution of respiratory diseases represents a considerable public health challenge, as they are among the leading causes of death worldwide. In this sense, in addition to the high prevalence of diseases such as asthma, chronic obstructive pulmonary disease, pneumonia, cystic fibrosis, and lung cancer, emerging respiratory diseases, particularly those caused by members of the coronavirus family, have contributed to a significant number of deaths on a global scale over the last two decades. Therefore, several studies have been conducted to optimize the efficacy of treatments against these diseases, focusing on pulmonary drug delivery using nanomedicine. Thus, the development of nanocarriers has emerged as a promising alternative to overcome the limitations of conventional therapy, by increasing drug bioavailability at the target site and reducing unwanted side effects. In this context, nanoparticles composed of chitosan (CS) show advantages over other nanocarriers because chitosan possesses intrinsic biological properties, such as anti-inflammatory, antimicrobial, and mucoadhesive capacity. Moreover, CS nanoparticles have the potential to enhance drug stability, prolong the duration of action, improve drug targeting, control drug release, optimize dissolution of poorly soluble drugs, and increase cell membrane permeability of hydrophobic drugs. These properties could optimize the performance of the drug after its pulmonary administration. Therefore, this review aims to discuss the potential of chitosan nanoparticles for pulmonary drug delivery, highlighting how their biological properties can improve the treatment of pulmonary diseases, including their synergistic action with the encapsulated drug.

A cross-sectional study on the nasopharyngeal microbiota of individuals with SARS-CoV-2 infection across three COVID-19 waves in India

Background

Multiple variants of the SARS-CoV-2 virus have plagued the world through successive waves of infection over the past three years. Independent research groups across geographies have shown that the microbiome composition in COVID-19 positive patients (CP) differs from that of COVID-19 negative individuals (CN). However, these observations were based on limited-sized sample-sets collected primarily from the early days of the pandemic. Here, we study the nasopharyngeal microbiota in COVID-19 patients, wherein the samples have been collected across the three COVID-19 waves witnessed in India, which were driven by different variants of concern.

Methods

The nasopharyngeal swabs were collected from 589 subjects providing samples for diagnostics purposes at the Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad, India and subjected to 16s rRNA gene amplicon - based sequencing.

Findings

We found variations in the microbiota of symptomatic vs. asymptomatic COVID-19 patients. CP showed a marked shift in the microbial diversity and composition compared to CN, in a wave-dependent manner. Rickettsiaceae was the only family that was noted to be consistently depleted in CP samples across the waves. The genera Staphylococcus, Anhydrobacter, Thermus, and Aerococcus were observed to be highly abundant in the symptomatic CP patients when compared to the asymptomatic group. In general, we observed a decrease in the burden of opportunistic pathogens in the host microbiota during the later waves of infection.

Interpretation

To our knowledge, this is the first analytical cross-sectional study of this scale, which was designed to understand the relation between the evolving nature of the virus and the changes in the human nasopharyngeal microbiota. Although no clear signatures were observed, this study shall pave the way for a better understanding of the disease pathophysiology and help gather preliminary evidence on whether interventions to the host microbiota can help in better protection or faster recovery.

N-dihydrogalactochitosan reduces mortality in a lethal mouse model of SARS-CoV-2

The rapid emergence and global dissemination of SARS-CoV-2 that causes COVID-19 continues to cause an unprecedented global health burden resulting in nearly 7 million deaths. While multiple vaccine countermeasures have been approved for emergency use, additional treatments are still needed due to sluggish vaccine rollout, vaccine hesitancy, and inefficient vaccine-mediated protection. Immunoadjuvant compounds delivered intranasally can guide non-specific innate immune responses during the critical early stages of viral replication, reducing morbidity and mortality. N-dihydrogalactochitosan (GC) is a novel mucoadhesive immunostimulatory polymer of β-0-4-linked N-acetylglucosamine that is solubilized by the conjugation of galactose glycans with current applications as a cancer immunotherapeutic. We tested GC as a potential countermeasure for COVID-19. GC was well-tolerated and did not produce histopathologic lesions in the mouse lung. GC administered intranasally before and after SARS-CoV-2 exposure diminished morbidity and mortality in humanized ACE2 receptor expressing mice by up to 75% and reduced infectious virus levels in the upper airway. Fluorescent labeling of GC shows that it is confined to the lumen or superficial mucosa of the nasal cavity, without involvement of adjacent or deeper tissues. Our findings demonstrate a new application for soluble immunoadjuvants such as GC for preventing disease associated with SARS-CoV-2 and may be particularly attractive to persons who are needle-averse.

New potential anti-SARS-CoV-2 and anti-cancer therapies of chitosan derivatives and its nanoparticles: Preparation and characterization

Chitosan (CS) is a biopolymer and has reactive amine/hydroxyl groups facilitated its modifications. The purpose of this study is improvement of (CS) physicochemical properties and its capabilities as antiviral and antitumor through modification with 1-(2-oxoindolin-3-ylidene)thiosemicarbazide (3A) or 1-(5-fluoro-2-oxoindolin-3-ylidene)thiosemicarbazide (3B) via crosslinking of poly(ethylene glycol)diglycidylether (PEGDGE) using microwave-assisted as green technique gives (CS-I) and (CS-II) derivatives. However, (CS) derivatives nanoparticles (CS-I NPs) and (CS-II NPs) are synthesized via ionic gelation technique using sodium tripolyphosphate (TPP). Structures of new (CS) derivatives are characterized using different tools. The anticancer, antiviral efficiencies and molecular docking of (CS) and its derivatives are assayed. (CS) derivatives and its nanoparticles show enhancement in cell inhibition toward (HepG-2 and MCF-7) cancer cells in comparison with (CS). (CS-II NPs) reveals the lowest IC₅₀ values are 92.70 ± 2.64 μg/mL and 12.64 µ g/mL against (HepG-2) cell and SARS-CoV-2 (COVID-19) respectively and the best binding affinity toward corona virus protease receptor (PDB ID 6LU7) -5.71 kcal / mol. Furthermore, (CS-I NPs) shows the lowest cell viability% 14.31 ± 1.48 % and the best binding affinity -9.98 kcal/moL against (MCF-7) cell and receptor (PDB ID 1Z11) respectively. Results of this study demonstrated that (CS) derivatives and its nanoparticles could be potentially employed for biomedical applications.

Biopharmaceutical applications of microbial polysaccharides as materials: A review

Biological characteristics of natural polymers make microbial polysaccharides an excellent choice for biopharmaceuticals. Due to its easy purifying procedure and high production efficiency, it is capable of resolving the existing application issues associated with some plant and animal polysaccharides. Furthermore, microbial polysaccharides are recognized as prospective substitutes for these polysaccharides based on the search for eco-friendly chemicals. In this review, the microstructure and properties of microbial polysaccharides are utilized to highlight their characteristics and potential medical applications. From the standpoint of pathogenic processes, in-depth explanations are provided on the effects of microbial polysaccharides as active ingredients in the treatment of human diseases, anti-aging, and drug delivery. In addition, the scholarly developments and commercial applications of microbial polysaccharides as medical raw materials are also discussed. The conclusion is that understanding the use of microbial polysaccharides in biopharmaceuticals is essential for the future development of pharmacology and therapeutic medicine.

Anti-COVID-19 Credentials of Chitosan Composites and Derivatives: Future Scope?

Chitosan derivatives and composites are the next generation polymers for biomedical applications. With their humble origins from the second most abundant naturally available polymer chitin, chitosan is currently one of the most promising polymer systems, with wide biological applications. This current review gives a bird’s eye view of the antimicrobial applications of chitosan composites and derivatives. The antiviral activity and the mechanisms behind the inhibitory activity of these components have been reviewed. Specifically, the anti-COVID-19 aspects of chitosan composites and their derivatives have been compiled from the existing scattered reports and presented. Defeating COVID-19 is the battle of this century, and the chitosan derivative-based combat strategies naturally become very attractive. The challenges ahead and future recommendations have been addressed.

Nanocarrier-based drug delivery system in herpes simplex virus treatment

Herpes simplex virus (HSV) is a highly contagious DNA virus that affects the majority of people worldwide. HSV establishes a latent infection in the ganglia, where it can reactivate, leading to recurrent disease. Currently, there are many experimental vaccines against HSV, but none have been used to treat herpes infections. At the same time, the therapeutic effect of existing anti-HSV drugs is limited. Nanocarriers, which deliver drugs to specific targets, have been used in different diseases, including viral infections. Nanocarriers could be designed to encapsulate drugs and directly target infected cells. This review will describe in detail the use of nanocarriers for targeted therapy of HSV infection.

Nanomedicine as a Potential Tool against Monkeypox

Human monkeypox is a rare viral zoonosis that was first identified in 1970; since then, this infectious disease has been marked as endemic in central and western Africa. The disease has always been considered rare and self-limiting; however, recent worldwide reports of several cases suggest otherwise. Especially with monkeypox being recognized as the most important orthopoxvirus infection in humans in the smallpox post-eradication era, its spread across the globe marks a new epidemic. Currently, there is no proven treatment for human monkeypox, and questions about the necessity of developing a vaccine persist. Notably, if we are to take lessons from the COVID-19 pandemic, developing a nanomedicine-based preventative strategy might be prudent, particularly with the rapid growth of the use of nanotechnology and nanomaterials in medical research. Unfortunately, the collected data in this area is limited, dispersed, and often incomplete. Therefore, this review aims to trace all reported nanomedicine approaches made in the monkeypox area and to suggest possible directions that could be further investigated to develop a counteractive strategy against emerging and existing viruses that could diminish this epidemic and prevent it from becoming a potential pandemic, especially with the world still recovering from the COVID-19 pandemic.

Worldwide fight against COVID-19 using nanotechnology, polymer science, and 3D printing technology

One of the lethal illnesses that humanity has ever seen is COVID-19 irrefutably. The speed of virus spread is high and happens through polluted surfaces, respiratory droplets, and bodily fluids. It was found that without an efficient vaccine or specific treatment using personal protective equipment, preventing contamination of hands, and social distancing are the best ways to stay safe during the present pandemic. In this line, polymers, nanotechnology, and additive manufacturing, or 3D printing technology have been considered to probe, sense, and treat COVID-19. All aforementioned fields showed undeniable roles during the COVID-19 pandemic, which their contributions have been reviewed here. Finally, the effect of COVID-19 on the environment, alongside its positive and negative effects has been mentioned.

The Health and Clinical Benefits of Medicinal Fungi

The human uses of mushrooms and cultured mycelium products for nutrition and medicine are detailed and supported by available human studies, which in many cases are clinical trials published in peer-reviewed journals. The major medically active immunomodulating compounds in the cell walls-chitin, beta-glucans, and glycoproteins, as well as lower weight molecules-nitrogen-containing compounds, phenolics, and terpenes-are discussed in relation to their current clinical uses. The nutritional content and foods derived from mushrooms, particularly related to their medical benefits, are discussed. High-quality major nutrients such as the high amounts of complete protein and prebiotic fibers found in edible and medicinal fungi and their products are presented. Mushrooms contain the highest amount of valuable medicinal fiber, while dried fruiting bodies of some fungi have up to 80% prebiotic fiber. These fibers are particularly complex and are not broken down in the upper gut, so they can diversify the microbiome and increase the most beneficial species, leading to better immune regulation and increasing normalizing levels of crucial neurotransmitters like serotonin and dopamine. Since the growth of medicinal mushroom products is expanding rapidly worldwide, attention is placed on reviewing important aspects of mushroom and mycelium cultivation and quality issues relating to adulteration, substitution, and purity and for maximizing medicinal potency. Common questions surrounding medicinal mushroom products in the marketplace, particularly the healing potential of fungal mycelium compared with fruiting bodies, extraction methods, and the use of fillers in products, are all explored, and many points are supported by the literature.

The evolution of the global COVID-19 epidemic in Morocco and understanding the different therapeutic approaches of chitosan in the control of the pandemic

In 2020, Coronavirus disease (COVID-19), a new viral respiratory disease caused by a virus that belongs to Coronaviridae family, has been identified. It is a very severe flu that negatively affects the functions of the lung and other respiratory organs. COVID-19 virus can be transmitted between people either by touching an infected person or by direct contact with their respiratory droplets. Therefore, the COVID-19 virus has become a global concern due to its rapid spread and severity. Based on the World Health Organization report from 2 March 2020 to 24 October 2022, the total infected cases and deaths in Morocco are around 1,265,389 (3.46%) and 16,280 (0.04%), respectively. Recently, some scientists have found that chitosan, a polymer existed in nature, can inhibit COVID-19 infection and repair damaged tissue. Therefore, understanding chitosan mechanisms in controlling COVID-19, might lead to innovative strategies in the medical field, such as developing drugs against SARS-CoV-2, and replacing vaccines, which have negative side effects. This review aims to show the evolution of the COVID-19 pandemic worldwide, specifically in Morocco, its pathophysiology, and its ability to silence the immune system. This review also provides an overview of the treatments and measures applied to protect human beings and how chitosan acts and controls COVID-19.

Chitosan-Based Nanomaterial as Immune Adjuvant and Delivery Carrier for Vaccines

With the support of modern biotechnology, vaccine technology continues to iterate. The safety and efficacy of vaccines are some of the most important areas of development in the field. As a natural substance, chitosan is widely used in numerous fields-such as immune stimulation, drug delivery, wound healing, and antibacterial procedures-due to its good biocompatibility, low toxicity, biodegradability, and adhesion. Chitosan-based nanoparticles (NPs) have attracted extensive attention with respect to vaccine adjuvants and delivery systems due to their excellent properties, which can effectively enhance immune responses. Here, we list the classifications and mechanisms of action of vaccine adjuvants. At the same time, the preparation methods of chitosan, its NPs, and their mechanism of action in the delivery system are introduced. The extensive applications of chitosan and its NPs in protein vaccines and nucleic acid vaccines are also introduced. This paper reviewed the latest research progress of chitosan-based NPs in vaccine adjuvant and drug delivery systems.

Synthesis of bee venom loaded chitosan nanoparticles for anti-MERS-COV and multi-drug resistance bacteria

This study aims to fully exploit the natural compound; bee venom (BV) as a substance that can kill and inhibit the growth of microbes and viruses. For this target, BV was loaded onto a safe, natural, and economically inexpensive polymer; chitosan (Ch) in its nano-size form prepared using ionic gelation method in the presence of chemical crosslinking agent (sodium tripolyphosphate; TPP). The findings illustrated that chitosan nanoparticles (ChNPs) were prepared thru this method and exhibited spherical shape and average hydrodynamic size of 202 nm with a polydispersity index (PDI = 0.44). However, the size was increased to 221 nm with PDI (0.37) when chitosan nanoparticles were loaded with BV (ChNC). In addition, the particles of BV appeared as a core and chitosan nanoparticles as a shell implying the successful preparation of nanocomposite (ChNC). Encapsulation of BV into ChNPs with significantly small size distribution and good stability that protect these formed nanocomposites from agglomeration. The cytopathic effect (CPE) inhibition assay was used to identify potential antivirals for Middle East respiratory syndrome coronavirus (MERS-CoV). The response of the dose study was designed to influence the range of effectiveness for the chosen antiviral, i.e., the 50 % inhibitory concentration (IC₅₀), as well as the range of cytotoxicity (CC₅₀). However, our results indicated that crude BV had mild anti-MERS-COV with selective index (SI = 4.6), followed by ChNPs that exhibited moderate anti-MERS-COV with SI = 8.6. Meanwhile. The nanocomposite of ChNC displayed a promising anti-MERS-COV with SI = 12.1. Additionally, the synthesized nanocomposite (ChNC) had greater antimicrobial activity against both Gram-positive and Gram-negative bacteria when compared with ChNPs, BV or the utilized model drug.

Chitosan-based nanoscale systems for doxorubicin delivery: Exploring biomedical application in cancer therapy

Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS-based nanoparticles (CS-NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS-NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P-glycoprotein (P-gp) to reverse drug resistance. These nanoarchitectures can provide co-delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co-loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid-, carbon-, polymeric- and metal-based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS-NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS-NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH-sensitive release of DOX can occur. Furthermore, redox- and light-responsive CS-NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS-NPs, we expect to soon see significant progress towards clinical translation.

Functionalized SPION immobilized on graphene-oxide: Anticancer and antiviral study

The progressive and fatal outbreak of some diseases such as cancer and coronavirus necessitates using advanced materials to bring such devastating illnesses under control. In this study, graphene oxide (GO) is decorated by superparamagnetic iron oxide nanoparticles (SPION) (GO/SPION) as well as polyethylene glycol functionalized SPION (GO/SPION@PEG), and chitosan functionalized SPION (GO/SPION@CS). Field emission scanning electron microscopic (FESEM) images show the formation of high density uniformly distributed SPION nanoparticles on the surface of GO sheets. The structural and chemical composition of nanostructures is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The saturation magnetization of GO/SPION, GO/SPION@PEG and GO- SPION@CS are found to be 20, 19 and 8 emu/g using vibrating sample magnetometer. Specific absorption rate (SAR) values of 305, 283, and 199 W/g and corresponding intrinsic loss power (ILP) values of 9.4, 8.7, and 6.2 nHm²kg^-1 are achieved for GO/SPION, GO/SPION@PEG and GO/SPION@CS, respectively. The In vitro cytotoxicity assay indicates higher than 70% cell viability for all nanostructures at 100, 300, and 500 ppm after 24 and 72 h. Additionally, cancerous cell (EJ138 human bladder carcinoma) ablation is observed using functionalized GO/SPION under applied magnetic field. More than 50% cancerous cell death has been achieved for GO/SPION@PEG at 300 ppm concentration. Furthermore, Surrogate virus neutralization test is applied to investigate neutralizing property of the synthesized nanostructures through analysis of SARS-CoV-2 receptor-binding domain and human angiotensin-converting enzyme 2 binding. The highest level of SARS-CoV-2 virus inhibition is related to GO/SPION@CS (86%) due to the synergistic exploitation of GO and chitosan. Thus, GO/SPION and GO/SPION@PEG with higher SAR and ILP values could be beneficial for cancer treatment, while GO/SPION@CS with higher virus suppression has potential to use against coronaviruses. Thus, the developed nanocomposites have a potential in the efficient treatment of cancer and coronavirus.

Nanoscale Technologies in the Fight against COVID-19: From Innovative Nanomaterials to Computer-Aided Discovery of Potential Antiviral Plant-Derived Drugs

The last few years have increasingly emphasized the need to develop new active antiviral products obtained from artificial synthesis processes using nanomaterials, but also derived from natural matrices. At the same time, advanced computational approaches have found themselves fundamental in the repurposing of active therapeutics or for reducing the very long developing phases of new drugs discovery, which represents a real limitation, especially in the case of pandemics. The first part of the review is focused on the most innovative nanomaterials promising both in the field of therapeutic agents, as well as measures to control virus spread (i.e., innovative antiviral textiles). The second part of the review aims to show how computer-aided technologies can allow us to identify, in a rapid and therefore constantly updated way, plant-derived molecules (i.e., those included in terpenoids) potentially able to efficiently interact with SARS-CoV-2 cell penetration pathways.

Molecular modifications, biological activities, and applications of chitosan and derivatives: A recent update

Polysaccharides arouse great interest due to their structure and unique properties, such as biocompatibility, biodegradability, and absence of toxicity. Polysaccharides from marine sources are particularly useful due to the wide variety of applications and biological activities. Chitosan, a deacetylated derivative of chitin, is an example of an interesting bioactive marine-derived polysaccharide. Moreover, a wide variety of chemical modifications and conjugation of chitosan with other bioactive molecules are responsible for improvements in physicochemical properties and biological activities, expanding the range of applications. An overview of the synthetic approaches for preparing chitosan, chitosan derivatives, and conjugates is described and discussed. A recent update of the biological activities and applications in different research fields, mainly focused on the last 5 years, is presented, highlighting current trends.

Low molecular weight chitooligosaccharide inhibits infection of SARS-CoV-2 in vitro

AIMS

The discovery of antiviral substances to respond to COVID-19 is a global issue, including the field of drug development based on natural materials. Here, we showed that chitosan-based substances have natural antiviral properties against SARS-CoV-2 in vitro.

METHODS AND RESULTS

The molecular weight of chitosan-based substances was measured by the gel permeation chromatography analysis. In MTT assay, the chitosan-based substances have low cytotoxicity to Vero cells. The antiviral effect of these substances was confirmed by quantitative viral RNA targeting the RdRp and E genes and plaque assay. Among the substances tested, low molecular weight chitooligosaccharide decreased the fluorescence intensity of SARS-CoV-2 nucleocapsid protein of the virus-infected cells in a dose-dependent manner.

CONCLUSIONS

In conclusion, the chitooligosaccharide, a candidate for natural treatment, has antiviral effects against the SARS-CoV-2 virus in vitro.

SIGNIFICANCE AND IMPACT OF STUDY

In this study, it was suggested for the first time that chitosan-based substances such as chitooligosaccharide can have an antiviral effect on SARS-CoV-2 in vitro.

Antiviral Polymers: A Review

Polymers, due to their high molecular weight, tunable architecture, functionality, and buffering effect for endosomal escape, possess unique properties as a carrier or prophylactic agent in preventing pandemic outbreak of new viruses. Polymers are used as a carrier to reduce the minimum required dose, bioavailability, and therapeutic effectiveness of antiviral agents. Polymers are also used as multifunctional nanomaterials to, directly or indirectly, inhibit viral infections. Multifunctional polymers can interact directly with envelope glycoproteins on the viral surface to block fusion and entry of the virus in the host cell. Polymers can indirectly mobilize the immune system by activating macrophages and natural killer cells against the invading virus. This review covers natural and synthetic polymers that possess antiviral activity, their mechanism of action, and the effect of material properties like chemical composition, molecular weight, functional groups, and charge density on antiviral activity. Natural polymers like carrageenan, chitosan, fucoidan, and phosphorothioate oligonucleotides, and synthetic polymers like dendrimers and sialylated polymers are reviewed. This review discusses the steps in the viral replication cycle from binding to cell surface receptors to viral-cell fusion, replication, assembly, and release of the virus from the host cell that antiviral polymers interfere with to block viral infections.

Synthesis and characterization of new functionalized chitosan and its antimicrobial and in-vitro release behavior from topical gel

Recently, chitosan and its derivatives have been gaining more attention due to their high integration into various biomedical applications. Herein, a new chitosan derivative was prepared by linking the chitosan (Cs) with a novel heterocyclic compound, Benzoimidazolyl-thiadiazole (BzimTD) to form Cs-BzimTD. The synthesis of the new chitosan derivative was confirmed by Fourier-Transform Infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (¹H NMR), thermogravimetric (TGA-DTG) analysis, elemental analysis, and UV-Visible spectrophotometer. Data showed the high efficacy of functionalized Cs-BzimTD to inhibit the growth of pathogenic microbes, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans, with inhibition zones of 15.3 ± 0.6 - 9.2 ± 0.3 mm. Also, Cs-BzimTD was applied in a topical gel formulation by using two different polymers, Carbopol 940 (CP) and Carboxymethyl Cellulose (CMC) to form three gel formulations: Cs-BzimTD-CP, Cs-BzimTD-CMC, and Cs-BzimTD-CP-CMC. The new gels were checked for physical appearance, viscosity, Cs-BzimTD release, pH, spread-ability, and drug content. The results showed that all formulations were clear, transparent, and homogeneous with non-irritant pH values for skin (6.4 - 6.8). The spread-ability was found in the range of 7.1 - 9.4 g.cm/s. The Cs-BzimTD-CP formula showed the maximal Cs-BzimTD content percentage (86.5%) and the Cs-BzimTD release varied from 89.9 to 81.6% after 8 h depending on the gel formulation, with a maximum release achieved for Cs-BzimTD-CMC.

Hydro electroactive Cu/Zn coated cotton fiber nonwovens for antibacterial and antiviral applications

In this study, Cu/Zn galvanic electrodes were sputtered on the two surfaces of hydrophilic cotton fiber nonwovens (Cotton) to prepare hydro electroactive Cu/Cotton/Zn composites. When the Cu/Cotton/Zn was used as a functional layer in the face mask, the Cu/Zn galvanic electrodes can be spontaneously activated by water vapor molecules exhaled by the human body and generate galvanic current. Based on this, the hydro electroactive Cu/Cotton/Zn demonstrated excellent antibacterial activity against Escherichia coli and Staphylococcus aureus and could deactivate Enterovirus 71 (EV71) virions transmitted through the respiratory tract by 97.72% after 15 min of contact. Moreover, the Cu/Cotton/Zn did not affect the particle filtration efficiency and breathability of the face mask's polypropylene (PP) melt-blown layer. Furthermore, the cytotoxicity assessment of Cu/Cotton/Zn showed no cytotoxicity, indicating good biological security. Overall, the Cu/Cotton/Zn may provide a new approach to increase the antibacterial and antiviral performance of current personnel protective equipment on the market.

Application of Chitosan and Its Derivative Polymers in Clinical Medicine and Agriculture

Chitosan is a biodegradable natural polymer derived from the exoskeleton of crustaceans. Because of its biocompatibility and non-biotoxicity, chitosan is widely used in the fields of medicine and agriculture. With the latest technology and technological progress, different active functional groups can be connected by modification, surface modification, or other configurations with various physical, chemical, and biological properties. These changes can significantly expand the application range and efficacy of chitosan polymers. This paper reviews the different uses of chitosan, such as catheter bridging to repair nerve broken ends, making wound auxiliaries, as tissue engineering repair materials for bone or cartilage, or as carriers for a variety of drugs to expand the volume or slow-release and even show potential in the fight against COVID-19. In addition, it is also discussed that chitosan in agriculture can improve the growth of crops and can be used as an antioxidant coating because its natural antibacterial properties are used alone or in conjunction with a variety of endophytic bacteria and metal ions. Generally speaking, chitosan is a kind of polymer material with excellent development prospects in medicine and agriculture.

Polysaccharides and Тheir Derivatives as Potential Antiviral Molecules

In the current context of the COVID-19 pandemic, it appears that our scientific resources and the medical community are not sufficiently developed to combat rapid viral spread all over the world. A number of viruses causing epidemics have already disseminated across the world in the last few years, such as the dengue or chinkungunya virus, the Ebola virus, and other coronavirus families such as Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV). The outbreaks of these infectious diseases have demonstrated the difficulty of treating an epidemic before the creation of vaccine. Different antiviral drugs already exist. However, several of them cause side effects or have lost their efficiency because of virus mutations. It is essential to develop new antiviral strategies, but ones that rely on more natural compounds to decrease the secondary effects. Polysaccharides, which have come to be known in recent years for their medicinal properties, including antiviral activities, are an excellent alternative. They are essential for the metabolism of plants, microorganisms, and animals, and are directly extractible. Polysaccharides have attracted more and more attention due to their therapeutic properties, low toxicity, and availability, and seem to be attractive candidates as antiviral drugs of tomorrow.

Cyanobacteria and Algae-Derived Bioactive Metabolites as Antiviral Agents: Evidence, Mode of Action, and Scope for Further Expansion; A Comprehensive Review in Light of the SARS-CoV-2 Outbreak

COVID-19—a severe acute respiratory syndrome disease caused by coronavirus 2 (SARS-CoV-2)—has recently attracted global attention, due to its devastating impact, to the point of being declared a pandemic. The search for new natural therapeutic drugs is mandatory, as the screening of already-known antiviral drugs so far has led to poor results. Several species of marine algae have been reported as sources of bioactive metabolites with potential antiviral and immunomodulatory activities, among others. Some of these bioactive metabolites might be able to act as antimicrobial drugs and also against viral infections by inhibiting their replication. Moreover, they could also trigger immunity against viral infection in humans and could be used as protective agents against COVID-In this context, this article reviews the main antiviral activities of bioactive metabolites from marine algae and their potential exploitation as anti-SARS-CoV-2 drugs.

Potential Application of Bionanoparticles to Treat Severe Acute Respiratory Syndrome Coronavirus-2 Infection

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a contagious virus that spreads exponentially across the world, resulting in serious viral pneumonia. Several companies and researchers have put their tremendous effort into developing novel vaccines or drugs for the complete eradication of COVID-19 caused by SARS-CoV-2. Bionanotechnology plays a vital role in designing functionalized biocompatible nanoparticulate systems with higher antiviral capabilities. Thus, several nanocarriers have been explored in designing and delivering drugs and vaccines. This problem can be overcome with the intervention of biomaterials or bionanoparticles. The present review describes the comparative analysis of SARS infection and its associated etiological agents. This review also highlighted some nanoparticles that have been explored in the treatment of COVID-19. However, these carriers elicit several problems once they come in contact with biological systems. Often, the body’s immune system treats these nanocarriers as foreign particles and antigens. In contrast, some bionanoparticles are highlighted here with their potential application in SARS-CoV-2. However, bionanoparticles have demonstrated some drawbacks discussed here with the possible outcomes. The scope of bioinspired nanoparticles is also discussed in detail to explore the new era of research. It is highly essential for the effective delivery of these nanoparticles to the target site. For effective management of SARS-CoV-2, different delivery patterns are also discussed here.

Chitosan Nanoparticles for Antiviral Drug Delivery: A Novel Route for COVID-19 Treatment

Chitosan has been investigated in several biological fields, including drug and gene delivery, tissue engineering antiviral and immunological adjuvant methods. It's a cationic copolymer of N-acetyl glucosamine and D-glucosamine with different molecular chain lengths, compositions, and sequences than N-acetyl glucosamine and D-glucosamine. It is biocompatible and cyto-compatible, as well as recyclable and bioresorbable. As effective drug delivery methods, chitosan nanoparticles are shaped into several pathways. The purpose of this article is to provide an overview of its antiviral application as a nanocarrier for antiviral medications, highlighting the benefits, limitations, and downsides. In this review, we will report the most recent COVID-19 vaccination advances. It will also be discussed what the future holds for chitosan nanoparticles in the treatment of coronaviruses.

Polymer-Based Nanosystems-A Versatile Delivery Approach

Polymer-based nanoparticles of tailored size, morphology, and surface properties have attracted increasing attention as carriers for drugs, biomolecules, and genes. By protecting the payload from degradation and maintaining sustained and controlled release of the drug, polymeric nanoparticles can reduce drug clearance, increase their cargo's stability and solubility, prolong its half-life, and ensure optimal concentration at the target site. The inherent immunomodulatory properties of specific polymer nanoparticles, coupled with their drug encapsulation ability, have raised particular interest in vaccine delivery. This paper aims to review current and emerging drug delivery applications of both branched and linear, natural, and synthetic polymer nanostructures, focusing on their role in vaccine development.

Effects of molecular weight of chitosan on anti-inflammatory activity and modulation of intestinal microflora in an ulcerative colitis model

This study investigated the therapeutic effects and mechanisms of chitosans (CSs) with different molecular weights on ulcerative colitis (UC). Three size classes of CSs (Mw ≤ 3, 50, and 200 kDa) were used in this study. The effect of large CSs (Mw ≤ 200 kDa) on UC was the best, followed by that of medium CSs (Mw ≤ 50 kDa), and that of small CSs (Mw ≤ 3 kDa) was the least in the LPS-induced Raw 264.7 cell model and DSS-induced UC mice model. The therapeutic mechanisms of three CSs are related to anti-oxidation, anti-inflammation, and regulation of immunoglobulin and intestinal flora by attenuating body weight loss, decreasing the disease activity index (DAI) and MPO activity, suppressing proinflammatory cytokines and IgG levels, down-regulating the level of oxidative stress, increasing anti-inflammatory cytokines, SOD activity and Prevotellaceae_UCG-001 levels, and reducing the abundance of Proteobacteria, Actinobacteria, and Escherichia-Shigella. In general, the molecular weight of CSs influences their efficacy against UC. CSs with an optimal molecular weight demonstrate good development prospects for ameliorating UC.

Potential of mucoadhesive chitosan glutamate microparticles as microbicide carriers - antiherpes activity and penetration behavior across the human vaginal epithelium

Chitosan glutamate (gCS) spray-dried microparticles appear promising carriers to overcome challenges associated with vaginal microbicide delivery. This study aimed at elucidating the penetration and mucoadhesive behavior of developed gCS multiunit carriers with zidovudine (ZVD) as a model antiretroviral agent in contact with excised human vaginal epithelium followed with an examination of in vitro antiherpes activity in immortal human keratinocytes HaCaT and human vaginal epithelial cells VK2-E6/E7. Both ZVD dispersion and placebo microparticles served as controls. Microparticles displayed feasible (comparable to commercial vaginal product) mucoadhesive and mucoretention characteristics to isolated human vaginal tissue. Ex vivo penetration studies revealed that gCS increased the accumulation of active agent in the vaginal epithelium but surprisingly did not facilitate its penetration across human tissue. Finally, the obtained antiviral results demonstrated the potential of gCS as an antiherpes adjunctive, whose mode of action was related to blocking viral attachment.

Recent Advances in Chitin and Chitosan/Graphene-Based Bio-Nanocomposites for Energetic Applications

Herein, we report recent developments in order to explore chitin and chitosan derivatives for energy-related applications. This review summarizes an introduction to common polysaccharides such as cellulose, chitin or chitosan, and their connection with carbon nanomaterials (CNMs), such as bio-nanocomposites. Furthermore, we present their structural analysis followed by the fabrication of graphene-based nanocomposites. In addition, we demonstrate the role of these chitin- and chitosan-derived nanocomposites for energetic applications, including biosensors, batteries, fuel cells, supercapacitors and solar cell systems. Finally, current limitations and future application perspectives are entailed as well. This study establishes the impact of chitin- and chitosan-generated nanomaterials for potential, unexplored industrial applications.

Preparation and Antimicrobial Activity of Chitosan and Its Derivatives: A Concise Review

Despite the advantages presented by synthetic polymers such as strength and durability, the lack of biodegradability associated with the persistence in the environment for a long time turned the attention of researchers to natural polymers. Being biodegradable, biopolymers proved to be extremely beneficial to the environment. At present, they represent an important class of materials with applications in all economic sectors, but also in medicine. They find applications as absorbers, cosmetics, controlled drug delivery, tissue engineering, etc. Chitosan is one of the natural polymers which raised a strong interest for researchers due to some exceptional properties such as biodegradability, biocompatibility, nontoxicity, non-antigenicity, low-cost and numerous pharmacological properties as antimicrobial, antitumor, antioxidant, antidiabetic, immunoenhancing. In addition to this, the free amino and hydroxyl groups make it susceptible to a series of structural modulations, obtaining some derivatives with different biomedical applications. This review approaches the physico-chemical and pharmacological properties of chitosan and its derivatives, focusing on the antimicrobial potential including mechanism of action, factors that influence the antimicrobial activity and the activity against resistant strains, topics of great interest in the context of the concern raised by the available therapeutic options for infections, especially with resistant strains.

Role of chitosan based nanomedicines in the treatment of chronic respiratory diseases

Chitosan-loaded nanomedicines provide a greater opportunity for the treatment of respiratory diseases. Natural biopolymer chitosan and its derivatives have a large number of proven pharmacological actions like antioxidant, wound healing, immuno-stimulant, hypocholesterolemic, antimicrobial, obesity treatment, anti-inflammatory, anticancer, bone tissue engineering, antifungal, regenerative medicine, anti-diabetic and mucosal adjuvant, etc. which attracted its use in the pharmaceutical industry. As compared to other polysaccharides, chitosan has excellent mucoadhesive characteristics, less viscous, easily modified into the chemical and biological molecule and gel-forming property due to which the drugs retain in the respiratory tract for a longer period of time providing enhanced therapeutic action of the drug. Chitosan-based nanomedicines would have the greatest effect when used to transport poor water soluble drugs, macromolecules like proteins, and peptides through the lungs. In this review, we highlight and discuss the role of chitosan and its nanomedicines in the treatment of chronic respiratory diseases such as pneumonia, asthma, COPD, lung cancer, tuberculosis, and COVID-19.