Cationic Chitosan Research Articles

In Vitro Microbiological and Drug Release of Silver/Ibuprofen Loaded Wound Dressing Designed for the Treatment of Chronically Infected Painful Wounds.

This study consisted of developing a dressing loaded with silver (Ag) and ibuprofen (IBU) that provides a dual therapy, antibacterial and antalgic, intended for infected painful wounds. Therefore, non-woven polyethyleneterephtalate (PET) textiles nonwovens were pre-treated by cyclodextrin crosslinked with citric acid by a pad/dry/cure process. Then, textiles were impregnated in silver solution followed by a thermal treatment and were then coated by Layer-by-Layer (L-b-L) deposition of a polyelectrolyte multilayer (PEM) system consisting of anionic water-soluble poly(betacyclodextrin citrate) (PCD) and cationic chitosan. Finally, ibuprofen lysinate (IBU-L) was loaded on the PEM coating. We demonstrated the complexation of IBU with native βCD and PCD by phase solubility diagram and 1H NMR. PEM system allowed complete IBU-L release in 6 h in PBS pH 7.4 batch (USP IV). On the other hand, microbiological tests demonstrated that loaded silver induced bacterial reduction of 4 Log10 against S. aureus and E. coli and tests revealed that ibuprofen lysinate loading did not interfere with the antibacterial properties of the dressing.

Hemocompatibility and Hemolytic Effects of Functionalized Nanoparticles on Red Blood Cells: A Recent Review Study

In this paper (from 2010 to 2020), the effects of polymeric, metallic and nonmetallic nanoparticles on red blood cells’ hemocompatibility were investigated for the first time. Here, we have considered the latest findings which can help to improve the hemocompatibility of RBCs. It is important to maintain the quality of red blood cells for improving the hemocompatibility because blood products directly affect the health of patients after blood transfusion. Although RBCs can be stored for up to 42 days at 2–6∘C, hypothermic storage lesions (HSLs) are very common in these products. This problem affects the quality of RBC products. Thus, it is necessary to modify the surface molecules of RBCs during storage time to reduce HSLs and alloimmunization complications. Therefore, we reviewed the reported effects of polymeric, metallic and carbon-based nanoparticles on RBCs between 2010 and 2020. The results of our study have shown that the use of negatively charged dendrimers, unsaturated/uncharged liposomes, and PEGylated forms of NPs and RBCs are the best approaches to improve the hemocompatibility conditions of red blood cells. However, large cationic dendrimers, liposomes composed of saturated lipid with long acyl chain, and cationic chitosan nanoparticles have less RBC compatibility. In addition, polymeric nanoparticles have more capacity for surface modification, which makes it possible to make more hemocompatible derivatives. Among metallic nanoparticles, gold and iron nanoparticles were more RBC compatible. However, the smaller size, higher concentration and longer exposure time of these nanoparticles can induce hemolysis and morphological changes in RBCs. On the other side, nonmetallic nanoparticles mostly had poor RBC compatibility, but their effects on RBCs strongly depended on their concentration and physicochemical properties and could be controllable. As a result, the use of polyethylene glycol (PEG), gold, polymeric, and iron nanoparticles in the design of protocols to maintain the survival, structure and activity of red blood cells for improving hemocompatibility can be more effective.

Development of Microstructure and Properties of Multicomponent MoS2/HA/PEEK Coatings on a Titanium Alloy Via Electrophoretic Deposition and Heat Treatment

In this study, molybdenum disulfide nanosheets, bioactive hydroxyapatite particles of two types in various amounts, and PEEK 704 microparticles were electrophoretically co-deposited to fabricate multicomponent coatings on Ti-13Nb-13Zr alloy substrates. A mixture of pure ethanol and cationic chitosan polyelectrolyte was used as a dispersion medium. The kinetics and mechanism of deposition were investigated. The kinetics depended significantly on the suspension’s chemical composition and the voltage used during EPD. Cationic chitosan provided the steric stabilization of the suspension and enabled cathodic co-deposition of all coating components. Green macroscopically homogeneous coatings were subsequently heat treated. The treatment densified the coatings and caused the formation of a stable semi-crystalline PEEK matrix consisting of spherulites. The MoS2 nanosheet packages, separate HA particles and their agglomerates were embedded in the coating matrix. After heat treatment, both types of coatings, differing in HA type, were characterized by excellent adhesion to the substrate and moderate scratch resistance. During surface topography investigation, it was found that coatings containing smaller HA nanoparticles had a slightly lower surface roughness. The coatings raised the corrosion resistance of the titanium alloy substrate in Ringer’s solution. The possibility of the electrophoretic co-deposition of various ceramic and PEEK particles to develop multicomponent coatings, as well as their contribution to enhancing titanium alloy surface properties, represents an important input in further developing superior bioactive titanium implants.

Synergistic Photodynamic and Photothermal Antibacterial Activity of In Situ Grown Bacterial Cellulose/MoS2-Chitosan Nanocomposite Materials with Visible Light Illumination.

Owing to the rise in prevalence of multidrug-resistant pathogens attributed to the overuse of antibiotics, infectious diseases caused by the transmission of microbes from contaminated surfaces to new hosts are an ever-increasing threat to public health. Thus, novel materials that can stem this crisis, while also functioning via multiple antimicrobial mechanisms so that pathogens are unable to develop resistance to them, are in urgent need. Toward this goal, in this work, we developed in situ grown bacterial cellulose/MoS2-chitosan nanocomposite materials (termed BC/MoS2-CS) that utilize synergistic membrane disruption and photodynamic and photothermal antibacterial activities to achieve more efficient bactericidal activity. The BC/MoS2-CS nanocomposite exhibited excellent antibacterial efficacy, achieving 99.998% (4.7 log units) and 99.988% (3.9 log units) photoinactivation of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, respectively, under visible-light illumination (xenon lamp, 500 W, λ ≥ 420 nm, and 30 min). Mechanistic studies revealed that the use of cationic chitosan likely facilitated bacterial membrane disruption and/or permeability, with hyperthermia (photothermal) and reactive oxygen species (photodynamic) leading to synergistic pathogen inactivation upon visible-light illumination. No mammalian cell cytotoxicity was observed for the BC/MoS2-CS membrane, suggesting that such composite nanomaterials are attractive as functional materials for infection control applications.

Dual pH responsive via double - layered microencapsulation for controlled release of active ingredients in simulated gastrointestinal tract: A model case of chitosan-alginate microcapsules containing basil oil (Ocimum basilicum Linn.)

Phytogenic feed additives (PFAs) have gained more attention to replace antibiotic growth promoters (AGPs) in poultry industry. However, the efficiency of PEAs might be lost during feed pelleting, storage and gastrointestinal (GI) tract resulting in an insufficient level at the small intestine. The present work demonstrates the use of double-layered polymers with opposite charges leading to a dual pH responsiveness where the encapsulated ingredients are remained active through the acidic gastric stage and ready to be released at the intestine. Anionic sodium alginate (SA) and cationic chitosan (CS) are a good combination to represent double-layered polymer of which an effective incorporation of active ingredient, i.e. basil oil (BO), a model PEA, can be achieved. By simply fabricating SA porous microcapsules followed by the absorption of BO before the surface coating with CS, the double-layered microcapsules, CS-SA, are obtained. The release performances confirm that CS-SA retains the antioxidant and antimicrobial activities of BO under storage in addition to a great tolerance of acids, bile, trypsin, including the thermal conditions. The present work, for the first time, proposes the concept of porous double-layered polymer in microcapsule form which shows the dual pH responsive for controlled release application. The use of ionic polysaccharides is simple, biocompatible and environmentally friendly, whereas the plausible upscaling for wide range of controlled release applications has to be further investigated.

Использование пленок, обогащенных антоциановым пигментом, в качестве индикатора свежести рыбного фарша

Introduction. Smart food packaging that alerts consumers to spoilt food by changing color is based on affordable and biodegradable raw materials. The research objective was to develop films from anionic polysaccharides and anthocyanin pigment that can be used as a freshness indicator of minced fish.
 Study objects and methods. The study featured frozen black currant berries (Ríbes nígrum), polysaccharide-based anthocyanin films, and minced fish. Extracts of anthocyanin pigment and films based on agar, kappa-carrageenan, chitosan, starch, and anthocyanin pigments were analyzed by IR spectroscopy.
 Results and its discussion. Anionic polysaccharides, i.e. agar and kappa-carrageenan, demonstrated good film-forming properties. Films based on 1.5% agar and 2% kappa-carrageenan showed elasticity, resilience, plasticity, and sufficient resistance to mechanical deformation. Neutral polysaccharide starch and cationic polysaccharide chitosan appeared to have no such qualities. An IR spectral analysis revealed chemical interactions between polysaccharide and anthocyanin molecules. It indicated the electrostatic nature of the polyelectrolyte complexes of the anthocyanin pigment with anionic polysaccharides. A film based on 1.5% agar fortified with anthocyanin pigment was used as a test-system for analyzing the quality of fish. The minced fish samples were wrapped in the anthocyanin film and left for 2–7 min to register the color change of the film. When the anthocyanin film came in contact with fresh fish, the color of the film did not change even after prolonged contact. When the film came into contact with spoilt fish, the color of the film began to change after 2 min of contact. When the contact time reached 7 min, the film turned blue.
 Conclusion. The type of polysaccharide and the interaction between polysaccharides and anthocyanin pigment had a significant effect on film formation. Anionic polysaccharides demonstrated the best results. Electrostatic interactions between anionic polysaccharides and anthocyanin pigments produced stable polyelectrolyte complexes. The new smart films were able to determine the quality of minced fish.

Cationic chitosan@Ruthenium dioxide hybrid nanozymes for photothermal therapy enhancing ROS-mediated eradicating multidrug resistant bacterial infection

Antibiotic resistanceand biofilm formation are the main challenges of bacterial infectious diseases, and enhancing the permeability of drugs to biofilms may be a promising strategy. Herein, we constructed a cationic chitosan coated ruthenium dioxide nanozyme (QCS-RuO2@RBT, SRT NSs)。RuO2 nanosheets (RuO2 NSs) are modified with positively charged Quaternary ammonium-chitosan (QCS) to improve biocompatibility, and enhance the interaction between RuO2 nanozymes and bacterial membranes. An antibacterial drug, [Ru(bpy)2(tip)]2+ (RBT) can be loaded onto QCS-RuO2 by π-π stacking and hydrophobic interaction. SRT NSs exhibit NIR light enhanced peroxidase-like catalytic activity, thereby effectively fighting against planktonic bacteria and damaging biofilms. In the biofilm, extracellular DNA (eDNA) was cleaved by high levels of hydroxyl radicals (•OH) catalyzed by SRT NSs, thereby disrupting the rigid biofilm. In addition, in vivo studies demonstrate that SRT NSs can significantly rescue skin wound infections and the chronic lung infection in mice caused by P. aeruginosa, and hold the same therapeutic efficacy as first‐line clinically anchored anti P. aeruginosa drug ciprofloxacin. Accordingly, the research work has realized the efficient production of ·OH, and the permeability of drugs to biofilms.it provides a promising response strategy for the management of biofilm-associated infections, including chronic lung infection.

In vitro-in vivo evaluation of olopatadine incorporated chitosan nanoparticles for the treatment of ocular allergy

In this study, antihistaminic agent Olopatadine hydrochloride (OLO) was incorporated into chitosan nanoparticles for the treatment of ocular allergy. Nanoparticles were prepared with spray drying method. Physicochemical properties and efficacy of the formulations were evaluated by in vitro and in vivo studies. SEM analyses were performed for the determination of morphology of the particles. Particle size analyses showed that particles were within the nanometer range (119 ± 9 nm to 227 ± 18 nm) with relatively homogenous size distribution (0.453 ± 0.078 to 0.643 ± 0.124 PDI data). Regarding cationic character of chitosan, nanoparticles were cationic as expected with zeta potentials within the range of +27.8 ± 0.3 mV to +35.5 ± 1.2 mV. DSC, FT-IR and 1H NMR analyses revealed the physical integrity of nanoparticles. High encapsulation efficacy up to 73.33 ± 0.25% were detected by ultra-high performance liquid chromatography (U-HPLC) method. For the determination of corneal residence time of nanoparticles in vivo studies were performed on sheeps. Analyses results revealed that, ocular residence time was enhanced up to 24 h with single instillation. As a result of the study OLO incorporated cationic chitosan nanoparticles remained on the ocular surface for longer periods due to the electrostatic interactions with negatively charged corneal surface, which will provide effective treatment of ocular allergy.

Factor XIII Cross-Linked Adhesive Chitosan Hydrogels.

Biomedical adhesives have been found to be an attractive alternative to suturing in several circumstances. However, to date most of the clinically approved formulations are based on synthetic and highly reactive toxic chemicals. In this work, we aimed to combine for the first time the bioactive properties of the cationic polysaccharide chitosan and its intrinsic electrostatic binding to negatively charged tissues with the biocompatible and clinically compliant enzymatic cross-linking scheme of fibrin glue. This synergistic activity led to the generation of a transglutaminase Factor XIII cross-linkable chitosan formulation with fast gelation kinetics, tunable mechanical properties, antibacterial activity, and strong adhesion to cartilage.

Chlorin e6 conjugated chitosan as an efficient photoantimicrobial agent

The development of antibacterial agents with high bacteria-binding capability and antibacterial efficiency is highly desirable. Herein, cationic polysaccharide chitosan (CS) was combined with photosensitizer Chlorin e6 (Ce6) to construct a novel photodynamic antibacterial agent (CS-Ce6 conjugates) for combating gram-positive bacteria Staphylococcus aureus (S. aureus) and gram-negative bacteria Escherichia coli (E. coli). CS-Ce6 conjugates with different degrees of substitution (DS) were synthesized and characterized by a spectroscopic method and organic elemental analysis to understand the relationship between structure and antibacterial effect. CS-Ce6 conjugates revealed good reactive oxygen species (ROS) generation ability and photodynamic antibacterial effect. Meanwhile, they both were positively correlated with DS in the range of 4.81% ~ 11.56% resulting in stronger photodynamic antibacterial ability. These findings highlight that CS-Ce6 conjugates have the potential as an effective photodynamic bactericidal agent in the antibacterial field.

The use of natural organic flocculants for harvesting microalgae grown in municipal wastewater at different culture densities.

Harvesting microalgae from liquid culture is a difficult issue to solve and is most commonly done through settling. However, settling is a slow process on its own and generally needs to be induced chemically or by introducing stress to the culture. Polymeric, cationic substances, such as cationised starch and chitosan, are often used for flocculation and settling. These large, positively charged molecules form large clusters with suspended particles in the liquid medium. In the present study, three natural organic flocculants (cationic starch, chitosan and acacia tannin S5T) were tested to harvest microalgal cultures grown in wastewater. Two microalgal species, one strain of Chlorella vulgaris and one strain of Scenedesmus obliquus, were cultured in municipal wastewater for different lengths of time, and settled using either cationic starch, chitosan or acacia tannin S5T. Results indicated that S5T worked with approximately the same efficiency in the two assayed species, although it requires a relatively high dosage to function (about 300 mg L-1 ), while the other two flocculants varied from species to species.

COMPATIBILITY SCREENING OF VIDAGLIPTIN WITH IONIC AND NON-IONIC POLYMERIC EXCIPIENTS FOR THE DESIGN OF EXTENDED RELEASE DELIVERY SYSTEM

Studies of drug-polymer compatibility play an important role in the preformulation stage for the development of pharmaceutical dosage forms. The potential physical and chemical interactions between drugs and polymer can affect the chemical nature, stability and bioavailability of the dosage form and as a result in the therapeutic response in the clinical phase. The present study reveals the thermal and spectroscopic study of physical mixtures of Vildagliptin (VDG) and HPMC in combination with cationic polymers chitosan, anionic polymers NaCMC and nonionic polymers PEO for extended release (ER). In the first phase of the study, differential scanning calorimeter (DSC) was used as tool to detect any interaction. In the next phase, a Fourier Transform Infrared Spectroscopy (FT-IR) technique was used to confirm and to investigate the type of the possible interactions between the components. In both cases, the spectroscopic data revealed that the analysed polymeric excipients did not show any affect on the VDG. Results of the present study indicated the suitability of the HPMC K4M hydrophilic matrix polymers in combination with cationic polymers, anionic polymers and non-ionic polymers in the preparation of extended release formulation of VDG.

High water content hydrogels with instant mechanical recovery, anti-high temperature and anti-high ionic strength properties

In this work, we show how simple mixing of mineral clay materials and a biopolymer chitosan to afford hydrogel composites with significantly enhanced performances in instant mechanical recovery and self-healing, anti-high temperature and anti-high ionic strength activities. Benefited by the electrostatic attraction between anionic clay and cationic chitosan, molecular level coassembly was achieved, which gave rise to a robust and rapidly self-healable hydrogel. Synergistic effect between components enhanced the mechanical strength more than 10 folds and shortened the self-healable time more than 40 folds (from 220 s to less than 5 s). In addition, the binary hydrogel show extremely enhanced anti-temperature and ionic strength properties. This study offers a feasible and dramatically facile protocol to build functional hydrogel materials using commercially available mineral and biopolymer, which have promising applications in special areas such as underground oil and gas engineering.

Functional modification of cellulose by chitosan and gamma radiation for higher grafting of UV protective natural chromophores

This study demonstrated a green functionalization process of a cellulose substrate by combining the chitosan treatment and gamma radiation. To impart the UV protection characteristics in the cellulosic structure, natural chromophores derived from Banana floral stem (BFS) was grafted in the functionalized cellulose surface. Phytochemical screening was performed to confirm the types of UV protective natural chromophores (UVPNCs) presented in BFS. The result exhibited the presence of condensed tannin, flavonoids, anthocyanin, betacyanin, and anthraquinone as the major UVPNC components in BFS. The optimum conditions for maximum sorption of UVPNCs into the functionalized cellulose matrix were recorded at 80°C for 60 min. The cationic biopolymer chitosan (2 g/L), different gamma absorbs doses (2, 4, and 6 kGy), and combined chitosan and gamma treatment into cellulose resulted around 15–23%, 44%, and 41–64% improved absorption of UVPNCs, respectively, as demonstrated by the change in color strength (K/S) compared to unmodified cellulose matrix. The concurrent treatments greatly improved the total crystallinity index (TCI), hydrogen bond intensity (HBI), hydrogen bonding energy (EH), hydrogen bonding distance (R) and asymmetric factor (AF) from 1.358 to 1.363, 0.971 to 0.988, 27.15 kJ–27.40 kJ (at 3274 cm−1), 2.766 Å to 2.764 Å (at 3274 cm−1) and 0.47 to 0.10, respectively. For gamma treatment, 6 kGy irradiation dose provided the best result for improved molecular orientation of cellulose and in combination of chitosan the substrate attained a maximum K/S of 1.98 after UVPNCs grafting. It was found that the UV protection factor (UPF) rating has a linear relationship with the UVPNCs absorption (K/S) and a maximum four-fold increase in UPF (165–506) was evident. The excellent bonding durability of the UVPNCs grafted samples was further ensured in terms of several colorfastness properties. This sustainable functionalization of cellulose with high UPF offers a great promise for applications in health care and photodegradation protection.

Influence of selective acid-etching on functionality of halloysite-chitosan nanocontainers for sustained drug release

The functionality of halloysite (Hal) nanotubes as drug carriers can be improved by lumen enlargement and polymer modification. This study investigates the influence of selective acid etching on Hal functionalization with cationic biopolymer chitosan. Hal was subjected to lumen etching under mild conditions, loaded under vacuum with nonsteroidal antiinflammatory drug aceclofenac, and incubated in an acidic solution of chitosan. The functionality of pristine and etched Hal before and upon polymer functionalization was assessed by ζ-potential measurements, structural characterization (FT-IR, DSC and XRPD analysis), cell viability assay, drug loading and drug release studies.Acid etching increased specific surface area, pore volume and pore size of Hal, decreased ζ-potential and facilitated binding of the cationic polymer. XRPD and DSC analysis revealed crystalline structure of etched Hal. Successful chitosan binding and drug entrapment were further confirmed by FT-IR and DSC studies. XRPD showed surface polymer binding. DSC and FT-IR analyses confirmed the presence of the entrapped drug in its crystalline form. Drug loading was increased for ≈81% by selective lumen etching. Slight decrease of drug content occurred during chitosan functionalization due to aceclofenac diffusion in the polymer solution. The drug release was more sustained from etched Hal nanocomposites (up to ≈87% for 12 h) than from pristine Hal (up to ≈97% for 12 h) due to more intensive chitosan binding. High human fibroblast survival rates upon exposure to pristine and etched Hal before and after chitosan functionalization (>90% in the concentration of 1000 μg/mL) confirmed that both lumen etching under mild conditions and polymer functionalization had no significant effect on cytocompatibility.Based on these findings, selective lumen etching in combination with polycation modification appears to be a promising approach for improvement of Hal nanotubes functionality by increasing payload, polymer binding capacity, and sustained release properties with no significant effect on their cytocompatibility.

Multifunctional nanocomposite active packaging materials: Immobilization of quercetin, lactoferrin, and chitosan nanofiber particles in gelatin films

The design and fabrication of multifunctional films from natural materials is a major focus of modern packaging research with the aim of creating smart, active, and/or biodegradable packaging. In this study, multifunctional films were created by embedding different kinds of functional nanoparticles into a gelatin-based film prepared by a casting method. The nanoparticles were prepared by crosslinking cationic chitosan nanofibers using anionic sodium tripolyphosphate ions. In some cases, quercetin, lactoferrin, or both were incorporated into these nanoparticles. The nanoparticles were mixed with the hot gelatin solution prior to casting. The appearance, light-screening, water vapor barrier, thermal, mechanical, antimicrobial, antioxidant, and biodegradability/composting characteristics of the nanoparticle-loaded films were then characterized. Dynamic light scattering showed that the size, polydispersity, and charge of the functional nanoparticles depended on their composition. The spectroscopic analysis identified the importance of electrostatic and hydrogen bonds in film formation. Incorporation of the functional nanoparticles into the gelatin films improved their optical, mechanical, barrier, and preservative properties. For instance, the incorporation of quercetin increased the ability of the films to screen UV-light, whereas the incorporation of both lactoferrin and quercetin increased the antimicrobial and antioxidant properties of the films. Finally, the films were shown to have good biodegradability/composting under environmental conditions, which is important for reducing the negative environmental impacts caused by synthetic packaging.

A green all-polysaccharide hydrogel platform for sensing and electricity harvesting/storage

Multi-functional polysaccharide-based gels have gained increasing interest for various applications because of their biodegradability, flexibility and porous structure. This paper focuses on the exploration of an all-polysaccharide hydrogel platform for sensing and electricity harvesting/storage, with hydrogels consisting of cationic guar gum (CGG) and chitosan (CS). The gelling and crosslinking are due to the imine and acetal formations between carbonyl groups in polysaccharides, which are in-situ generated via the sodium periodate (NaIO4) oxidation, and their hydroxyl/amine groups. Consequently, CS/CGG hydrogel is fabricated without any crosslinking agents, and it exhibits injectability, conductivity, adhesiveness, etc. Thanks to its pressure responsiveness, the CS/CGG hydrogel accurately detects human motions. More importantly, it generates an output voltage of 32.1 mV upon moist air flow blowing, due to the abundant hydrophilic groups. Furthermore, the aerogel obtained by freeze-drying of CS/CGG hydrogel produces a voltage up to 162.2 mV, demonstrating its good electricity harvesting capacity. The carbon aerogel obtained from the calcination of CS/CGG aerogel exhibits good electrochemical performance with a high capacity and capacitance retention (ca. 90% after 10,000 consecutive cycles). Thus, this work provides a novel strategy to design a sustainable hydrogel platform for many applications, which may provide inspiration for all-natural functional material development.

Chitosan-based multi-liposomal complexes: Synthesis, biodegradability and cytotoxicity

Anionic liposomes were electrostatically adsorbed onto the surface of cationic chitosan particles cross-linked by sulfate anions, forming multi-liposomal containers (MLCs) for encapsulation and delivery of bioactive substances. An increase in molecular mass of chitosan from 30 to 300 kDa results in a size increase of chitosan particles, from 200 to 400 nm. Being saturated by liposomes, chitosan particles give MLCs of 320–540 nm. Each chitosan particle carries between 60 and 200 liposomes. The proteolytic complex Morikrase, a mixture of enzymes with various specificities, induces degradation of MLCs down to particles of size 10–15 nm; the higher the molecular mass of chitosan, the slower the enzyme-induced MLCs' degradation. pH variation within 5.5–7 and cholesterol incorporation into the liposomal membrane both have a minor effect on the rate of MLCs' biodegradation. Both the MLCs and the products of their biodegradation show low cytotoxicity. These results are of interest for constructing biodegradable capacious carriers of bioactive substances.

Antibacterial cotton from novel phytic acid-based multilayer nanocoating

In an effort to impart antimicrobial behavior to cotton using renewable and environmentally benign components, fabric was treated using layer-by-layer (LbL) assembly. Alternating layers of phytic acid (PA) and chitosan (CH) were deposited from water. Cotton coated with four and eight bilayers (BLs) of anionic PA and cationic CH, with and without adding copper (II) sulfate (CuSO4) into the CH solution, was evaluated in accordance with the American Association of Textile Chemists and Colorists (AATCC) TM 100-2019 test method. Gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae were used to determine whether the addition of copper salt into a CH network improves antibacterial efficacy. The copper ions were successfully incorporated into the CH network formed using LbL assembly onto cotton fibers. The location of deposited copper ions was determined with electron microscopy. Just four BLs of PA/CH–copper (II) sulfate kill 100% of gram-positive and gram-negative bacteria and add only 5.2 wt% to the fabric. This nanocoating provides a unique opportunity to impart antibacterial behavior to textiles without harming the environment.

To control floating drug delivery system in a simulated gastric environment by adjusting the Shell layer formulation

BackgroundGastroretentive drug delivery system (GDDS) are novel systems that have been recently developed for treating stomach diseases. The key function of all GDDS systems is to control the retention time in the stomach. However, research into the bulk density or entanglement of polymers, especially regarding their effects on drug float and release times, is scarce.MethodsIn this research, we prepared the floating core-shell beads carrying tetracycline. The ratio of chitosan and xanthan gum in the shell layer was changed to modify polymer compactness. Tetracycline was encapsulated in the alginate core.ResultsUsing scanning electron microscopy (SEM) techniques, we observed that the shell formulation did not change the bead morphology. The cross-sectional images showed that the beads were highly porous. The interaction between anionic xanthan gum and cationic chitosan made the shell layer dense, resisting to the mass transfer in the shell layer. Due to the high mass transfer resistance to water penetration, the longer float and delivery time were caused by the dense surface of the beads. The cell culture demonstrated that floating core-shell beads were biocompatible. Importantly, the beads with tetracycline showed a significant prolonged anti-bacterial effect.ConclusionResearch results proved that the floating and releasing progress of core-shell beads can be well controlled by adjusting the shell layer formulation that could promote the function of gastroretentive drugs.