Sustainable functionalized chitosan based nano-composites for wound dressings applications: A review

Functionalized chitosan nanocomposites have been studied for wound dressing applications due to their excellent antibacterial and anti-fungal properties. Polysaccharides show excellent antibacterial and drug-release properties and can be utilized for wound healing. In this article, we comprise distinct approaches for chitosan functionalization, such as photosensitizers, dendrimers, graft copolymerization, quaternization, acylation, carboxyalkylation, phosphorylation, sulfation, and thiolation. The current review article has also discussed brief insights on chitosan nanoparticle processing for biomedical applications, including wound dressings. The chitosan nanoparticle preparation technologies have been discussed, focusing on wound dressings owing to their targeted and controlled drug release behavior. The future directions of chitosan research include; a) finding an effective solution for chronic wounds, which are unable to heal completely; b) providing effective wound healing solutions for diabetic wounds and venous leg ulcers; c) to better understanding the wound healing mechanism with such materials which can help provide the optimum solution for wound dressing; d) to provide an improved treatment option for wound healing.

Current Advances in Chitosan Nanoparticles Based Oral Drug Delivery for Colorectal Cancer Treatment

As per the WHO, colorectal cancer (CRC) caused around 935,173 deaths worldwide in 2020 in both sexes and at all ages. The available anticancer therapies including chemotherapy, radiotherapy and anticancer drugs are all associated with limited therapeutic efficacy, adverse effects and low chances. This has urged to emerge several novel therapeutic agents as potential therapies for CRC including synthetic and natural materials. Orally administrable and targeted drug delivery systems are attractive strategies for CRC therapy as they minimize the side effects, enhance the efficacy of anticancer drugs. Nevertheless, oral drug delivery till today faces several challenges like poor drug solubility, stability, and permeability. Various oral nano-based approaches and targeted drug delivery systems have been developed recently, as a result of the ability of nanoparticles to control the release of the encapsulant, drug targeting and reduce the number of dosages administered. The unique physicochemical properties of chitosan polymer assist to overcome oral drug delivery barriers and target the colon tumour cells. Chitosan-based nanocarriers offered additional improvements by enhancing the stability, targeting and bioavailability of several anti-colorectal cancer agents. Modified chitosan derivatives also facilitated CRC targeting through strengthening the protection of encapsulant against acidic and enzyme degradation of gastrointestinal track (GIT). This review aims to provide an overview of CRC pathology, therapy and the barriers against oral drug delivery. It also emphasizes the role of nanotechnology in oral drug targeted delivery system and the growing interest towards chitosan and its derivatives. The present review summarizes the relevant works to date that have studied the potential applications of chitosan-based nanocarrier towards CRC treatment.

Chitosan-Based Biocompatible Copolymers for Thermoresponsive Drug Delivery Systems: On the Development of a Standardization System

Chitosan is a natural polysaccharide that is considered to be biocompatible, biodegradable and non-toxic. The polymer has been used in drug delivery applications for its positive charge, which allows for adhesion with and recognition of biological tissues via non-covalent interactions. In recent times, chitosan has been used for the preparation of graft copolymers with thermoresponsive polymers such as poly-N-vinylcaprolactam (PNVCL) and poly-N-isopropylamide (PNIPAM), allowing the combination of the biodegradability of the natural polymer with the ability to respond to changes in temperature. Due to the growing interest in the utilization of thermoresponsive polymers in the biological context, it is necessary to increase the knowledge of the key principles of thermoresponsivity in order to obtain comparable results between different studies or applications. In the present review, we provide an overview of the basic principles of thermoresponsivity, as well as a description of the main polysaccharides and thermoresponsive materials, with a special focus on chitosan and poly-N-Vinyl caprolactam (PNVCL) and their biomedical applications.

Microencapsulated Recombinant Human Epidermal Growth Factor Ameliorates Osteoarthritis in a Murine Model

Osteoarthritis, a highly age-related and chronic inflammatory disorder with cartilage loss, causes patients difficultly in movement; there is no efficient and sustainable remedy for osteoarthritis currently. Although hyaluronic acid (HA) and platelet-rich plasma (PRP) have been used to alleviate osteoarthritis, the effects could be short and multiple injections might be required. To address this issue, we exploited the property of chitosan to encapsulate recombinant human epidermal growth factor and obtained microencapsulated rhEGF (Me-rhEGF). In the current study, we induced the osteoarthritis-like symptoms with monosodium iodoacetate (MIA) in rats and investigated the therapeutic effects of Me-rhEGF. Following administration of HA/Me-rhEGF in vivo, we observed that the total Mankin scores, cartilage oligomeric protein, C-telopeptide of type II collagen, IL-1β, IL-6, IL-17A, and TNF-α cytokines, nitric oxide, and prostaglandin E2 expressions were significantly inhibited. Our results also strongly indicate that individual use of HA or rhEGF slightly decreased the inflammation and restored the destructive joint structure, but was not as drastic as seen in the HA/Me-rhEGF. Moreover, HA/Me-rhEGF profoundly reduced cartilage destruction and proteoglycan loss and downregulated matrix metalloproteinase expressions. These findings reveal that the treatment of HA/Me-rhEGF could be more beneficial than the use of single HA or rhEGF in reliving osteoarthritis and demonstrate the therapeutic application of microencapsulation technology in difficult joint disorders. In essence, we believe that the Me-rhEGF could be promising for further research and development as a clinical treatment against osteoarthritis.

A new waterborne chitosan-based polyurethane hydrogel as a vehicle to transplant bone marrow mesenchymal cells improved wound healing of ulcers in a diabetic rat model

Foot ulcers, a common complication of diabetes, can cause physical incapacity and are derived from several factors, including poor wound healing. New therapeutic strategies are needed to minimize this complication for the sake of patients' health. We therefore developed a new chitosan- polyurethane hydrogel membrane (HPUC) and the test results confirmed that HPUC present low cytotoxicity and improved wound healing when used with mononuclear bone marrow fraction cells in the diabetic rat model. The biodegradable hydrogels were produced in block copolymer networks with a combination of chitosan blocks and biodegradable polyurethane. The membranes were characterized by FTIR, ¹³C-NMR and thermogravimetry. Swelling and hydrolytic degradation were also evaluated. The non-solubility of the membranes in good solvents and the chemical characterization confirmed that the network structure was formed between the PU and the chitosan through urea/urethane bonds. The findings confirm that the HPUC have interesting properties that make them suitable for wound healing applications.

Synthesis and characterisation of PEG modified chitosan nanocapsules loaded with thymoquinone

Thymoquinone (TQ), a major bioactive compound of Nigella sativa seeds has several therapeutic properties. The main drawback in bringing TQ to therapeutic application is that it has poor stability and bioavailability. Hence a suitable carrier is essential for TQ delivery. Recent studies indicate biodegradable polymers are potentially good carriers of bioactive compounds. In this study, polyethylene glycol (PEG) modified chitosan (Cs) nanocapsules were developed as a carrier for TQ. Aqueous soluble low molecular weight Cs and PEG was selected among different biodegradable polymers based on their biocompatibility and efficacy as a carrier. Optimisation of synthesis of nanocapsules was done based on particle size, PDI, encapsulation efficiency and process yield. A positive zeta potential value of +48 mV, indicating good stability was observed. Scanning electron microscope and atomic-force microscopy analysis revealed spherical shaped and smooth surfaced nanocapsules with size between 100 to 300 nm. The molecular dispersion of the TQ in Cs PEG nanocapsules was studied using X-ray powder diffraction. The Fourier transform infrared spectrum of optimised nanocapsule exhibited functional groups of both polymer and drug, confirming the presence of Cs, PEG and TQ. In vitro drug release studies showed that PEG modified Cs nanocapsules loaded with TQ had a slow and sustained release.

Pharmacological and toxicological assessment of innovative self-assembled polymeric micelles as powders for insulin pulmonary delivery

Aim: Explore the use of polymeric micelles in the development of powders intended for pulmonary delivery of biopharmaceuticals, using insulin as a model protein. Materials & methods: Formulations were assessed in vitro for aerosolization properties and in vivo for efficacy and safety using a streptozotocin-induced diabetic rat model. Results: Powders presented good aerosolization properties like fine particle fraction superior to 40% and a mass median aerodynamic diameter inferior of 6 μm. Endotracheally instilled powders have shown a faster onset of action than subcutaneous administration of insulin at a dose of 10 IU/kg, with pharmacological availabilities up to 32.5% of those achieved by subcutaneous route. Additionally, micelles improved the hypoglycemic effect of insulin. Bronchoalveolar lavage screening for toxicity markers (e.g., lactate dehydrogenase, cytokines) revealed no signs of lung inflammation and cytotoxicity 14 days postadministration. Conclusion: Developed powders showed promising safety and efficacy characteristics for the systemic delivery of insulin by pulmonary administration.

Marine Origin Polysaccharides in Drug Delivery Systems

Oceans are a vast source of natural substances. In them, we find various compounds with wide biotechnological and biomedical applicabilities. The exploitation of the sea as a renewable source of biocompounds can have a positive impact on the development of new systems and devices for biomedical applications. Marine polysaccharides are among the most abundant materials in the seas, which contributes to a decrease of the extraction costs, besides their solubility behavior in aqueous solvents and extraction media, and their interaction with other biocompounds. Polysaccharides such as alginate, carrageenan and fucoidan can be extracted from algae, whereas chitosan and hyaluronan can be obtained from animal sources. Most marine polysaccharides have important biological properties such as biocompatibility, biodegradability, and anti-inflammatory activity, as well as adhesive and antimicrobial actions. Moreover, they can be modified in order to allow processing them into various shapes and sizes and may exhibit response dependence to external stimuli, such as pH and temperature. Due to these properties, these biomaterials have been studied as raw material for the construction of carrier devices for drugs, including particles, capsules and hydrogels. The devices are designed to achieve a controlled release of therapeutic agents in an attempt to fight against serious diseases, and to be used in advanced therapies, such as gene delivery or regenerative medicine.

Combinatorial-Designed Epidermal Growth Factor Receptor-Targeted Chitosan Nanoparticles for Encapsulation and Delivery of Lipid-Modified Platinum Derivatives in Wild-Type and Resistant Non-Small-Cell Lung Cancer Cells

Development of efficient and versatile drug delivery platforms to overcome the physical and biological challenges in cancer therapeutics is an area of great interest, and novel materials are actively sought for such applications. Recent strides in polymer science have led to a combinatorial approach for generating a library of materials with different functional identities that can be "mixed and matched" to attain desired characteristics of a delivery vector. We have applied the combinatorial design to chitosan (CS), where the polymer backbone has been modified with polyethylene glycol, epidermal growth factor receptor-binding peptide, and lipid derivatives of varying chain length to encapsulate hydrophobic drugs. Cisplatin, cis-([PtCl2(NH3)2]), is one of the most potent chemotherapy drugs broadly administered for cancer treatment. Cisplatin is a hydrophilic drug, and in order for it to be encapsulated in the developed nanosystems, it was modified with lipids of varying chain length. The library of four CS derivatives and six platinum derivatives was self-assembled in aqueous medium and evaluated for physicochemical characteristics and cytotoxic effects in platinum-sensitive and -resistant lung cancer cells. The results show that the lipid-modified platinate encapsulation into CS nanoparticles significantly improved cellular cytotoxicity of the drug. In this work, we have also reinforced the idea that CS is a multifaceted system that can be as successful in delivering small molecules as it has been as a nucleic acids carrier.

Polymeric micelles in mucosal drug delivery: Challenges towards clinical translation

Polymeric micelles are nanostructures formed by the self-aggregation of copolymeric amphiphiles above the critical micellar concentration. Due to the flexibility to tailor different molecular features, they have been exploited to encapsulate motley poorly-water soluble therapeutic agents. Moreover, the possibility to combine different amphiphiles in one single aggregate and produce mixed micelles that capitalize on the features of the different components substantially expands the therapeutic potential of these nanocarriers. Despite their proven versatility, polymeric micelles remain elusive to the market and only a few products are currently undergoing advanced clinical trials or reached clinical application, all of them for the therapy of different types of cancer and administration by the intravenous route. At the same time, they emerge as a nanotechnology platform with great potential for non-parenteral mucosal administration. However, for this, the interaction of polymeric micelles with mucus needs to be strengthened. The present review describes the different attempts to develop mucoadhesive polymeric micelles and discusses the challenges faced in the near future for a successful bench-to-bedside translation.

Development of Budesonide Loaded Biopolymer Based Dry Powder Inhaler: Optimization, In Vitro Deposition, and Cytotoxicity Study

The progress in the development of DPI technology has boosted the use of sensitive drug molecules for lung diseases. However, delivery of these molecules from conventional DPI to the active site still poses a challenge with respect to deposition efficiency in the lung. At same time, serious systemic side effects of drugs have become a cause for concern. The developed budesonide loaded biopolymer based controlled release DPI had shown maximum in vitro lung deposition with least toxicity. The subject of present study, lactose-free budesonide loaded biopolymer based DPI, further corroborates the great potential of antiasthmatic drugs. This technology is expected to revolutionize the approaches towards enhanced therapeutic delivery of prospective drugs.

Reversal of multidrug resistance by the inhibition of ATP-binding cassette pumps employing "Generally Recognized As Safe" (GRAS) nanopharmaceuticals: A review

Pumps of the ATP-binding cassette superfamily (ABCs) regulate the access of drugs to the intracellular space. In this context, the overexpression of ABCs is a well-known mechanism of multidrug resistance (MDR) in cancer and infectious diseases (e.g., viral hepatitis and the human immunodeficiency virus) and is associated with therapeutic failure. Since their discovery, ABCs have emerged as attractive therapeutic targets and the search of compounds that inhibit their genetic expression and/or their functional activity has gained growing interest. Different generations of pharmacological ABC inhibitors have been explored over the last four decades to address resistance in cancer, though clinical results have been somehow disappointing. "Generally Recognized As Safe" (GRAS) is a U.S. Food and Drug Administration designation for substances that are accepted as safe for addition in food. Far from being "inert", some amphiphilic excipients used in the production of pharmaceutical products have been shown to inhibit the activity of ABCs in MDR tumors, emerging as a clinically translatable approach to overcome resistance. The present article initially overviews the classification, structure and function of the different ABCs, with emphasis on those pumps related to drug resistance. Then, the different attempts to capitalize on the activity of GRAS nanopharmaceuticals as ABC inhibitors are discussed.

Novel high-viscosity polyacrylamidated chitosan for neural tissue engineering: fabrication of anisotropic neurodurable scaffold via molecular disposition of persulfate-mediated polymer slicing and complexation

Macroporous polyacrylamide-grafted-chitosan scaffolds for neural tissue engineering were fabricated with varied synthetic and viscosity profiles. A novel approach and mechanism was utilized for polyacrylamide grafting onto chitosan using potassium persulfate (KPS) mediated degradation of both polymers under a thermally controlled environment. Commercially available high molecular mass polyacrylamide was used instead of the acrylamide monomer for graft copolymerization. This grafting strategy yielded an enhanced grafting efficiency (GE = 92%), grafting ratio (GR = 263%), intrinsic viscosity (IV = 5.231 dL/g) and viscometric average molecular mass (MW = 1.63 × 10⁶ Da) compared with known acrylamide that has a GE = 83%, GR = 178%, IV = 3.901 dL/g and MW = 1.22 × 10⁶ Da. Image processing analysis of SEM images of the newly grafted neurodurable scaffold was undertaken based on the polymer-pore threshold. Attenuated Total Reflectance-FTIR spectral analyses in conjugation with DSC were used for the characterization and comparison of the newly grafted copolymers. Static Lattice Atomistic Simulations were employed to investigate and elucidate the copolymeric assembly and reaction mechanism by exploring the spatial disposition of chitosan and polyacrylamide with respect to the reactional profile of potassium persulfate. Interestingly, potassium persulfate, a peroxide, was found to play a dual role initially degrading the polymers—“polymer slicing”—thereby initiating the formation of free radicals and subsequently leading to synthesis of the high molecular mass polyacrylamide-grafted-chitosan (PAAm-g-CHT)—“polymer complexation”. Furthermore, the applicability of the uniquely grafted scaffold for neural tissue engineering was evaluated via PC12 neuronal cell seeding. The novel PAAm-g-CHT exhibited superior neurocompatibility in terms of cell infiltration owing to the anisotropic porous architecture, high molecular mass mediated robustness, superior hydrophilicity as well as surface charge due to the acrylic chains. Additionally, these results suggested that the porous PAAm-g-CHT scaffold may act as a potential neural cell carrier.

Trimethyl and carboxymethyl chitosan carriers for bio-active polymer-inorganic nanocomposites

The carrier properties of carboxymethyl chitosan (CMC) and trimethyl chitosan (TMC) in combination with polyoxometalates (POMs) as inorganic drug prototypes are compared with respect to the influence of polymer matrix charge and structure on the emerging composites. A direct crosslinking approach with TMC and K(6)H(2)[CoW(11)TiO(40)]·13H(2)O ({CoW(11)TiO(40)}) as a representative anticancer POM affords nanocomposites with a size range of 50-90nm. The obtained POM-chitosan composites are characterized with a wide range of analytical methods, and POM encapsulation into positively charged TMC brings forward different nanocomposite morphologies and properties than CMC as a carrier material. Furthermore, uptake of fluorescein isothiocyanate (FITC) labeled POM-CMC and POM-TMC by HeLa cells was monitored, and the influence of chlorpromazine (CP) as inhibitor of the clathrin mediated pathway revealed different cellular uptake behavior of composites and pristine carriers. TMC/{CoW(11)TiO(40)} nanocomposites are taken up by HeLa cells after short incubation times around 30 min at low concentrations. The anticancer activity of pristine {CoW(11)TiO(40)} and its TMC-nanocomposites was investigated in vitro with MTT assays and compared to a reference POM.