Mucoadhesive 4-carboxybenzenesulfonamide-chitosan with antibacterial properties

Sulfonamide modified chitosan oligosaccharide with high nematicidal activity against Meloidogyne incognita

Chitosan oligosaccharide (COS) modification is a feasible way to develop novel green nematicides. This study involved the synthesis of various COS sulfonamide derivatives via hydroxylated protection and deprotection, which were then characterized using NMR, FTIR, MS, elemental analysis, XRD, and TG/DTG. In vitro experiments found that COS-alkyl sulfonamide derivatives (S6 and S11-S13) exhibited high mortality (>98 % at 1 mg/mL) against Meloidogyne incognita second-instar larvaes (J2s) among the derivatives. S6 can cause vacuole-like structures in the middle and tail regions of the nematode body and effectively inhibit egg hatching. In vivo tests have found that S6 has well control effects and low plant toxicity. Additionally, the structure-activity studies revealed that S6 with a high degree of substitution, a low molecular weight, and a sulfonyl bond on the amino group of the COS backbone exhibited increased nematicidal activity. The sulfonamide group is a potential active group for developing COS-based nematicides.

Fabrication and characterization of a new eco-friendly sulfonamide-chitosan derivative with enhanced antimicrobial and selective cytotoxicity properties

Chitosan (CH) exhibits low antimicrobial activity. This study addresses this issue by modifying the chitosan with a sulfonamide derivative, 3-(4-(N,N-dimethylsulfonyl)phenyl)acrylic acid. The structure of the sulfonamide-chitosan derivative (DMS-CH) was confirmed using Fourier transform infrared spectroscopy and Nuclear magnetic resonance. The results of scanning electron microscopy, thermal gravimetric analysis, and X-ray diffraction indicated that the morphology changed to a porous nature, the thermal stability decreased, and the crystallinity increased in the DMS-CH derivative compared to chitosan, respectively. The degree of substitution was calculated from the elemental analysis data and was found to be moderate (42%). The modified chitosan exhibited enhanced antimicrobial properties at low concentrations, with a minimum inhibitory concentration (MIC) of 50 µg/mL observed for B. subtilis and P. aeruginosa, and a value of 25 µg/mL for S. aureus, E. coli, and C. albicans. In the case of native chitosan, the MIC values doubled or more, with 50 µg/mL recorded for E. coli and C. albicans and 100 μg/mL recorded for B. subtilis, S. aureus, and P. aeruginosa. Furthermore, toxicological examinations conducted on MCF-7 (breast adenocarcinoma) cell lines demonstrated that DMS-CH exhibited greater toxicity (IC50 = 225.47 μg/mL) than pure CH, while still maintaining significant safety limits against normal lung fibroblasts (WI-38). Collectively, these results suggest the potential use of the newly modified chitosan in biomedical applications.

Direct Biocatalytic Processes for CO2 Capture as a Green Tool to Produce Value-Added Chemicals

Direct biocatalytic processes for CO₂ capture and transformation in value-added chemicals may be considered a useful tool for reducing the concentration of this greenhouse gas in the atmosphere. Among the other enzymes, carbonic anhydrase (CA) and formate dehydrogenase (FDH) are two key biocatalysts suitable for this challenge, facilitating the uptake of carbon dioxide from the atmosphere in complementary ways. Carbonic anhydrases accelerate CO₂ uptake by promoting its solubility in water in the form of hydrogen carbonate as the first step in converting the gas into a species widely used in carbon capture storage and its utilization processes (CCSU), particularly in carbonation and mineralization methods. On the other hand, formate dehydrogenases represent the biocatalytic machinery evolved by certain organisms to convert CO₂ into enriched, reduced, and easily transportable hydrogen species, such as formic acid, via enzymatic cascade systems that obtain energy from chemical species, electrochemical sources, or light. Formic acid is the basis for fixing C₁-carbon species to other, more reduced molecules. In this review, the state-of-the-art of both methods of CO₂ uptake is assessed, highlighting the biotechnological approaches that have been developed using both enzymes.

Bacterial cellulose adhesive patches designed for soft mucosal interfaces

The wet environment in the oral cavity is challenging for topical disease management approaches. The compromised material properties leading to weak adhesion and short retention (<8 h) in such environment result in frequent reapplication of the therapeutics. Composites of bacterial cellulose (BC) and carbene-based bioadhesives attempt to address these shortcomings. Previous designs comprised of aqueous formulations. The current design, for the first time, presents dry, shelf-stable cellulose patches for convenient ready-to-use application. The dry patches simultaneously remove tissue surface hydration while retaining carbene-based photocuring and offers on-demand adhesion. The dry patch prototypes are optimized by controlling BC/adhesive mole ratios and dehydration technique. The adhesion strength is higher than commercial denture adhesives on soft mucosal tissues. The structural integrity is maintained for a minimum of 7 days in aqueous environment. The patches act as selective nanoporous barrier against bacteria while allowing permeation of proteins. The results support the application of BC-based adhesive patches as a flexible platform for wound dressings, drug depots, or combination thereof.

Evaluating the Anticarcinogenic Activity of Surface Modified/Functionalized Nanochitosan: The Emerging Trends and Endeavors

Chitosan begins its humble journey from marine food shell wastes and ends up as a versatile nutraceutical. This review focuses on briefly discussing the antioxidant activity of chitosan and retrospecting the accomplishments of chitosan nanoparticles as an anticarcinogen. The various modified/functionalized/encapsulated chitosan nanoparticles and nanoforms have been listed and their biomedical deliverables presented. The anticancer accomplishments of chitosan and its modified composites have been reviewed and presented. The future of surface modified chitosan and the lacunae in the current research focus have been discussed as future perspective. This review puts forth the urge to expand the scientific curiosity towards attempting a variety of functionalization and surface modifications to chitosan. There are few well known modifications and functionalization that benefit biomedical applications that have been proven for other systems. Being a biodegradable, biocompatible polymer, chitosan-based nanomaterials are an attractive option for medical applications. Therefore, maximizing expansion of its bioactive properties are explored. The need for applying the ideal functionalization that will significantly promote the anticancer contributions of chitosan nanomaterials has also been stressed.

Functional properties of chitosan derivatives obtained through Maillard reaction: A novel promising food preservative

This review provides an insight about the functional properties of chitosan obtained through Maillard reaction to enhance the shelf life and food quality. Maillard reaction is a promising and safe method to obtain commercial water-soluble chitosan's through Schiff base linkage and Amadori or Heyns rearrangement. Likewise, chitosan derivatives exert an enhanced antimicrobial, antioxidant, and emulsifying properties due to the development of Maillard reaction products (MRPs) like reductones and melanoidins. Additionally, the application of chitosan-MRPs effectively inhibited the microbial spoilage, reduced lipid oxidative, and extended the shelf life and the quality of fresh food products. Therefore, understand the potential of chitosan-MRPs derivatives as a functional biomaterial to improve the postharvest quality and extending the shelf life of food products will scale up its application as a food preservative.

A cost-effective chitosan–oxine based thin film for a volatile acid vapour sensing application

A polymer film based chemosensor was developed through the immobilization of chitosan and oxine, for the detection of TFA vapors.

In situ composite ion-triggered gellan gum gel incorporating amino methacrylate copolymer microparticles: a therapeutic modality for buccal applicability

The aim of the current investigation is to delineate the buccal applicability of an in situ composite gel containing aceclofenac (AC) amino methacrylate copolymer microparticles (MPs), surmounting limitations of oral existing conventional therapy. AC Eudragit RL100 MPs were fabricated and statistically optimized using 2²4¹ factorial design. Better buccal applicability and enhanced localization were achieved by combining the optimum MPs with in situ ion-activated gellan gum gel. The crosslinking and gelation of in situ gel were investigated by morphological and solid state characterizations. Suitability for buccal delivery and in vivo therapeutic efficacy in inflammation model of rats were also assessed. Results showed that the best performing formula displayed particle size (PS) of 51.00 µm and high entrapment efficiency (EE%) of 94.73%. MPs were successfully entrapped inside the gel network of the composite system. Gelation tendency, pH, shear-thinning properties and mucoadhesivity of the prepared in situ composite gel guaranteed its buccal suitability. Sustained AC release features and promising in vitro anti-arthritic response were also demonstrated. Moreover, consistent and prolonged in vivo anti-inflammatory effect was achieved, relative to standard AC. Taken together; this study proves the potential of in situ composite gel as an appropriate therapeutic proposal for AC buccal delivery.

A Novel Micron-Size Particulate Formulation of Felodipine with Improved Release and Enhanced Oral Bioavailability Fabricated by Coaxial Electrospray

The antihypertensive drug felodipine (FD) is a typical biopharmaceutics classification system (BCS) II drug; thus, improving the dissolution rate of FD is very important to enhance its bioavailability. Besides, according to the in situ "close loop" perfusion assay, we found that the jejunum is the main absorptive site, then the duodenum and ileum. Consequently, a novel micron-size particulate of FD in a core-shell structure was fabricated by a coaxial electrospray technique; within the drug delivery system, Hypromellose K4M (HPMC K4M) was selected as a sheath material to prolong the retention time in the upper GI tract, while povidone K30 (PVP K30) was mixed with FD in the inner layer. The dissolution study in three different media (0.02% Tween-80 solution; phosphate buffer containing 0.02% Tween-80, pH 6.8; and HCl solution containing 0.02% Tween-80, pH 1.2) demonstrated that FD-loaded coaxial electrospray particles (F-COES) could greatly improve the dissolution of FD. Furthermore, in vivo pharmacokinetics revealed that F-COES emerged no changes in the half-life but significantly prolonged the t_max and increased the oral bioavailability. Collectively, this work supplies a promising drug release system that will improve the dissolution and enhance the bioavailability simultaneously for those poorly water-soluble drugs mainly absorbed in the upper GI tract.

Microporous Coatings of PEKK/SN Composites Integration with PEKK Exhibiting Antibacterial and Osteogenic Activity, and Promotion of Osseointegration for Bone Substitutes

To improve the antibacterial and osteogenic activities of poly(etherketoneketone) (PEKK), concentrated sulfuric acid (H₂SO₄) suspension with silicon nitride (SN) microparticle was utilized to modify PEKK surface. Through sulfonation reaction, microporous coatings of PEKK/SN composites were created on PEKK surface, which were integrated with PEKK substrate. The results showed that the content of SN in the microporous coatings increased with the increase of SN content in H₂SO₄ suspension (PKS without SN, PKSC5 and PKSC10 with 5 and 10 wt % SN content in H₂SO₄) and that the surface roughness and hydrophilicity of microporous coatings on PEKK were significantly improved with the SN content increasing. In addition, the microporous coating of PKSC10 with high SN content exhibited excellent antibacterial activity due to the synergistic action of the presence of amino (-NH₂) and sulfonic acid (-SO₃H) groups as well as the improvement of protein absorption. Moreover, the microporous coating of PKSC10 obviously stimulated adhesion, proliferation, and osteogenic differentiation of rat bone mesenchymal stem cells. Furthermore, histological and push-out load evaluation indicated that the microporous coating of PKSC10 significantly promoted osteogenesis and osseointegration in vivo. The results suggested that the microporous coating of PKSC10 with high SN content display good biocompatibility, antibacterial and osteogenic activities, and osseointegration ability, which would have great potential for bone substitutes.

Star-shaped poly(oligoethylene glycol) copolymer-based gels: Thermo-responsive behaviour and bioapplicability for risedronate intranasal delivery

The aim of this work was to obtain an intranasal delivery system with improved mechanical and mucoadhesive properties that could provide prolonged retention time for the delivery of risedronate (RS). For this, novel in situ forming gels comprising thermo-responsive star-shaped polymers, utilizing either polyethylene glycol methyl ether (PEGMA-ME 188, Mn 188) or polyethylene glycol ethyl ether (PEGMA-EE 246, Mn 246), with polyethylene glycol methyl ether (PEGMA-ME 475, Mn 475), were synthesized and characterized. RS was trapped in the selected gel-forming solutions at a concentration of 0.2% w/v. The pH, rheological properties, in vitro drug release, ex vivo permeation as well as mucoadhesion were also examined. MTT assays were conducted to verify nasal tolerability of the developed formulations. Initial in vivo studies were carried out to evaluate anti-osteoporotic activity in a glucocorticoid induced osteoporosis model in rats. The results showed successful development of thermo-sensitive formulations with favorable mechanical properties at 37 °C, which formed non-irritant, mucoadhesive porous networks, facilitating nasal RS delivery. Moreover, sustained release of RS, augmented permeability and marked anti-osteoporotic efficacy as compared to intranasal (IN) and intravenous (IV) RS solutions were realized. The combined results show that the in situ gels should have promising application as nasal drug delivery systems.

Thermo/pH dual-responsive core–shell particles for apatinib/doxorubicin controlled release: preparation, characterization and biodistribution

Schematic representation of the structure and functioning mechanism of DD particles.

An Overview of Chitosan Nanoparticles and Its Application in Non-Parenteral Drug Delivery

The focus of this review is to provide an overview of the chitosan based nanoparticles for various non-parenteral applications and also to put a spotlight on current research including sustained release and mucoadhesive chitosan dosage forms. Chitosan is a biodegradable, biocompatible polymer regarded as safe for human dietary use and approved for wound dressing applications. Chitosan has been used as a carrier in polymeric nanoparticles for drug delivery through various routes of administration. Chitosan has chemical functional groups that can be modified to achieve specific goals, making it a polymer with a tremendous range of potential applications. Nanoparticles (NP) prepared with chitosan and chitosan derivatives typically possess a positive surface charge and mucoadhesive properties such that can adhere to mucus membranes and release the drug payload in a sustained release manner. Chitosan-based NP have various applications in non-parenteral drug delivery for the treatment of cancer, gastrointestinal diseases, pulmonary diseases, drug delivery to the brain and ocular infections which will be exemplified in this review. Chitosan shows low toxicity both in vitro and some in vivo models. This review explores recent research on chitosan based NP for non-parenteral drug delivery, chitosan properties, modification, toxicity, pharmacokinetics and preclinical studies.

Sulfadiazine-Chitosan Conjugates and Their Polyelectrolyte Complexes with Hyaluronate Destined to the Management of Burn Wounds

In the present study polyelectrolyte complexes (PECs) based on new sulfadiazine-chitosan conjugates with sodium hyaluronate have been developed with potential use in treatment of burn wounds. The PECs were chemically characterized using Fourier Transform-Infrared Spectroscopy, Scanning Electon Microscopy and Near Infrared Chemical Imaging Technique. The swelling behavior and in vitro sulfadiazine release were also investigated. The antimicrobial activity was evaluated towards three bacterial strains: Escherichia coli, Listeria monocytogenes and Salmonella thyphymurium. The developed PECs demonstrated their antimicrobial efficiency against tested bacterial strains, the PECs containing sulfadiazine-modified chitosan being more active than PECs containing unmodified chitosan.

Self-assembly of mucoadhesive nanofibers

Here, we present an easy and stable one-step procedure to fabricate self-assembled nanofibers from modified chitosan.