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Abstract Background Oral ulcers are a common side effect of chemotherapy and affect patients’ quality of life. While stem cell transplantation is a potential treatment for oral ulcers, its efficacy is limited as the stem cells tend to remain in the affected area for a short time. This study aims to develop a treatment for oral ulcers by using trimethyl chitosan (TMC) hydrogel with human tonsil-derived stem cells (hTMSCs) to increase the therapeutic effect of stem cells and investigate their effectiveness. Methods Animals were divided into four experimental groups: Control, TMC hydrogel, hTMSCs, and hTMSCs loaded in TMC hydrogel (Hydrogel + hTMSCs) (each n = 8). Oral ulcers were chemically induced by anesthetizing the rats followed by injection of dilute acetic acid in the right buccal mucosa. After confirming the presence of oral ulcers in the animals, a single subcutaneous injection of 100 µL of each treatment was applied to the ulcer area. Histological analyses were performed to measure inflammatory cells, oral mucosal thickness, and fibrosis levels. The expression level of inflammatory cytokines was also measured using RT-PCR to gauge therapeutic the effect. Results The ulcer size was significantly reduced in the TMC hydrogel + hTMSCs group compared to the control group. The stem cells in the tissue were only observed until Day 3 in the hTMSCs treated group, while the injected stem cells in the TMC Hydrogel + hTMSCs group were still present until day 7. Cytokine analysis related to the inflammatory response in the tissue confirmed that the TMC Hydrogel + hTMSCs treated group demonstrated superior wound healing compared to other experimental groups. Conclusion This study has shown that the adhesion and viability of current stem cell therapies can be resolved by utilizing a hydrogel prepared with TMC and combining it with hTMSCs. The combined treatment can promote rapid healing of oral cavity wounds by enhancing anti-inflammatory effects and expediting wound healing. Therefore, hTMSC loaded in TMC hydrogel was the most effective wound-healing approach among all four treatment groups prolonging stem cell survival. However, further research is necessary to minimize the initial inflammatory response of biomaterials and assess the safety and long-term effects for potential clinical applications.

Background: Oral ulcers are a common side effect of chemotherapy and affect patients' quality of life. While stem cell transplantation is a potential treatment for oral ulcers, its efficacy is limited as the stem cells tend to remain in the affected area for a short time. This study aims to develop a treatment for oral ulcers by using trimethyl chitosan (TMC) hydrogel with human tonsil-derived stem cells (hTMSCs) to increase the therapeutic effect of stem cells and investigate their effectiveness. Methods: Animals were divided into four experimental groups: Control, TMC hydrogel, hTMSCs, and hTMSCs loaded in TMC hydrogel (Hydrogel + hTMSCs) (each n = 8). Oral ulcers were chemically induced by anesthetizing the rats followed by injection of dilute acetic acid in the right buccal mucosa. After confirming the presence of oral ulcers in the animals, a single subcutaneous injection of 100 µL of each treatment was applied to the ulcer area. Histological analyses were performed to measure inflammatory cells, oral mucosal thickness, and fibrosis levels. The expression level of inflammatory cytokines was also measured using RT-PCR to gauge therapeutic the effect. Results: The ulcer size was significantly reduced in the TMC hydrogel + hTMSCs group compared to the control group. The stem cells in the tissue were only observed until Day 3 in the hTMSCs treated group, while the injected stem cells in the TMC Hydrogel + hTMSCs group were still present until day 7. Cytokine analysis related to the inflammatory response in the tissue confirmed that the TMC Hydrogel + hTMSCs treated group demonstrated superior wound healing compared to other experimental groups. Conclusion: This study has shown that the adhesion and viability of current stem cell therapies can be resolved by utilizing a hydrogel prepared with TMC and combining it with hTMSCs. The combined treatment can promote rapid healing of oral cavity wounds by enhancing anti-inflammatory effects and expediting wound healing. Therefore, hTMSC loaded in TMC hydrogel was the most effective wound-healing approach among all four treatment groups prolonging stem cell survival. However, further research is necessary to minimize the initial inflammatory response of biomaterials and assess the safety and long-term effects for potential clinical applications. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) are arguably the most promising in terms of application among the noble metal nanoparticles. As such, researchers have dedicated a considerable amount of energy towards the synthesis of novel gold nanoparticles with different morphology and size, which in turn affect its potential application. This study synthesized novel spherical-shaped AuNPs via green reduction of gold ion in an aqueous solution of HAuCl4.3H2O in the presence of trimethyl chitosan as a stabilizing agent and pressurized H2 gas as a reducing agent on an ice water. The size, morphology, chemical composition, chemical environment and optical activities were examined by scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), x-ray photoelectron spectroscopy (XPS), and ultraviolet–visible spectroscopy (Uv–Visible), respectively. The average particle size of AuNPs is 37 nm while HR-TEM revealed a unique spherical morphology. The Tauc’s plot calculation revealed a band gap of 5.0 eV. This unique morphology and optical local field enhancement in plasmonic nanocomposites could be suitable alternative for conducting devices and photocatalysis. [ABSTRACT FROM AUTHOR]

Wound management practices have made significant advancements, yet the search for improved antiseptics persists. In our pursuit of solutions that not only prevent infections but also address broader aspects of wound care, we investigated the impact of integrating trimethyl chitosan (TMC) into a widely used poly(vinylpyrrolidone)-iodine gel (PVP-I gel). Our study assessed the antimicrobial efficacy of the PVP gel with TMC against Escherichia coli, Staphylococcus aureus, multidrug-resistant S. aureus MRSA, and Candida albicans. Additionally, we compared hemostatic effects using a liver puncture bleeding model and evaluated wound healing through histological sections from full-thickness dermal wounds in rats. The results indicate that incorporating TMC into the commercially available PVP-I gel did not compromise its antimicrobial activity. The incorporation of TMC into the PVP-I gel markedly improves its hemostatic activity. The regular application of the PVP-I gel with TMC resulted in an increased blood vessel count in the wound bed and facilitated the development of thicker fibrous tissue with a regenerated epidermal layer. These findings suggest that TMC contributes not only to antimicrobial activity but also to the intricate processes of tissue regeneration. In conclusion, incorporating TMC proves beneficial, making it a valuable additive to commercially available antiseptic agents. [ABSTRACT FROM AUTHOR]

Diosmin is a flavonoid derived from plants, possessing anti-inflammatory, antioxidant, antidiabetic, neuroprotective and cardiovascular protective properties. However, diosmin has low solubility in water, leading to low bioavailability. In this study, we constructed bilayer nanoparticles with trimethyl chitosan and soy peptides to improve the oral bioaccessibility and bioavailability of diosmin, and determined the characteristics and antioxidant properties of the diosmin-loaded nanoparticles. The results showed that the size of the nanoparticles was around 250 nm with the encapsulation efficiency higher than 97 %, and the nanoparticles were stable under regular conditions. In vitro digestion suggested the nanoparticles could protect diosmin from releasing in gastric digestion but promote the bioaccessibility of diosmin in intestine. Furthermore, the diosmin-loaded nanoparticles presented excellent antioxidant activities in vitro and significantly decreased the Lipopolysaccharides-induced brain Malondialdehyde (MDA) level by oral administration. Therefore, the reported nanoparticles may be an effective platform for improving the oral bioavailability of diosmin.

Fine dust and bioaerosols are significant public health concerns, showing the importance of protective measures. In this study, natural-based trimethyl chitosan, permanently burdened with a positive charge, was successfully distributed on the surface of melt-blown polypropylene sheets through a metal rod coating process. This surface modification was confirmed through scanning electron microscopy and X-ray photoelectron spectroscopy, indicating the surface adsorption of trimethyl chitosan without chemical bonding. Modifying polypropylene mask filters yielded a positive surface zeta potential for 10–20 g/m2 coat weight, increasing the filtration efficiency to 55–94 % in a standard particle filtration test using paraffin oil as a liquid aerosol. The filtration efficiency remained higher than conventional non-treated mask filters even after the humidification of sheets. In addition, the filtration test against fine dust particles, such as titanium dioxide, was performed with trimethyl chitosan-modified mask filters that captured up to 100–800 µg/m3 titanium oxide particle concentrations, showing better filtration than conventional mask filters in high fine dust events. Trimethyl chitosan-modified mask filters also exhibited potent inhibition, bactericidal, and antiviral effects against HCoV-OC43, reducing the virus infection rate by 93.69 %. Thus, trimethyl chitosan could be applied to several existing filter membranes to protect against particulate matter and dangerous airborne pathogens.

In this study, we tested the biosorption capacity of trimethyl chitosan (TMC)-ZnO nanocomposite (NC) for the adsorptive removal of Escherichia coli (E. coli) in aqueous suspension. For the formation of ZnO NPs, we followed the green synthesis route involving Terminalia mantaly (TM) aqueous leaf extract as a reducing agent, and the formed ZnO particles were surface-coated with TMC biopolymer. On testing of the physicochemical characteristics, the TM@ZnO/TMC (NC) hydrogel showed a random spherical morphology with an average size of 31.8 ± 2.6 nm and a crystal size of 28.0 ± 7.7 nm. The zeta potential of the composite was measured to be 23.5 mV with a BET surface area of 3.01 m2 g−1. The spectral profiles of TM@ZnO/TMC NC hydrogel on interaction with Escherichia coli (E. coli) revealed some conformational changes to the functional groups assigned to the stretching vibrations of N-H, C-O-C, C-O ring, and C=O bonds. The adsorption kinetics of TM@ZnO/TMC NC hydrogel revealed the pseudo-second-order as the best fit mechanism for the E. coli biosorption. The surface homogeneity and monolayer adsorption of the TM@ZnO/TMC NC hydrogel reflects majorly the entire adsorption mechanism, observed to display the highest correlation for Jovanovic, Redlich–Peterson, and Langmuir's isotherm models. Further, with the use of TM@ZnO/TMC NC hydrogel, we measured the highest adsorption capacity of E. coli to be 4.90 × 10 mg g−1, where an in-depth mechanistic pathway was proposed by making use of the FTIR analysis. [ABSTRACT FROM AUTHOR]

Amphotericin B (AmB) is an effective antifungal agent; however, the application of AmB is associated with a number of drawbacks. Application of nanoparticles (NPs) is known to improve the efficiency of drug delivery to the target tissues, compared to the traditional methods. In this study, a novel method of NPs preparation was developed. The trimethyl chitosan (TMC) was synthesized using low molecular weight chitosan and was used for the preparation of TMC-NPs through ionic gelation method. Afterward, AmB-loaded TMC-NPs (TMC-NPs/AmB) were prepared and their drug delivery potential was testes. The TMC-NPs and TMC-NPs/AmB were characterized for their structure, particle size, Zeta potential, polydispersity index, morphology, loading efficiency, loading capacity, in vitro release profile, release kinetic, and entrapped AmB potency. The cytotoxicity and antifungal activity of TMC-NPs/AmB against Candida albicans biofilm were evaluated. The quaternization of TMC was estimated to be 36.4%. The mean particle size of TMC-NPs and TMC NPs/AmB were 210±15 and 365±10 nm, respectively, with a PDI of 0.30 and 0.4, ZP of +34±0.5 and +28±0.5 mV, respectively. Electron microscopy analysis indicated uniform spherical shapes with smooth surfaces. The TMC-NPs/AmB indicated LE of 76% and LC of 74.04 % with a potency of 110%. The release profile of TMC-NPs/AmB was best explained by the Higuchi model. The initial release after 10 h was obtained at 38%, and the rates of release after 36 and 84 h were determined at 67% and 76% respectively, which was significantly different (P

In this study, we tested the biosorption capacity of trimethyl chitosan (TMC)-ZnO nanocomposite (NC) for the adsorptive removal of Escherichia coli (E. coli) in aqueous suspension. For the formation of ZnO NPs, we followed the green synthesis route involving Terminalia mantaly (TM) aqueous leaf extract as a reducing agent, and the formed ZnO particles were surface-coated with TMC biopolymer. On testing of the physicochemical characteristics, the TM@ZnO/TMC (NC) hydrogel showed a random spherical morphology with an average size of 31.8 ± 2.6 nm and a crystal size of 28.0 ± 7.7 nm. The zeta potential of the composite was measured to be 23.5 mV with a BET surface area of 3.01 m2 g−1. The spectral profiles of TM@ZnO/TMC NC hydrogel on interaction with Escherichia coli (E. coli) revealed some conformational changes to the functional groups assigned to the stretching vibrations of N-H, C-O-C, C-O ring, and C=O bonds. The adsorption kinetics of TM@ZnO/TMC NC hydrogel revealed the pseudo-second-order as the best fit mechanism for the E. coli biosorption. The surface homogeneity and monolayer adsorption of the TM@ZnO/TMC NC hydrogel reflects majorly the entire adsorption mechanism, observed to display the highest correlation for Jovanovic, Redlich–Peterson, and Langmuir’s isotherm models. Further, with the use of TM@ZnO/TMC NC hydrogel, we measured the highest adsorption capacity of E. coli to be 4.90 × 10 mg g−1, where an in-depth mechanistic pathway was proposed by making use of the FTIR analysis.

Multidrug-resistant bacterial infections pose a significant threat to human health, prompting the exploration of innovative solutions. In this study, a new series of antibacterial hybrid nanoparticles (HNPs) were developed. The HNPs are based on a combination of selenium nanoparticles (SeNPs), synthesized using Carica papaya leaf extract, and chitosan (CS/SeHNPs) or trimethyl chitosan (TMC/SeHNPs), respectively. Comprehensive characterization using UV‐Vis, FTIR, XRD, SEM-EDX, DLS, TEM, and DSC confirmed the structure and properties of the developed HNPs. SeNPs, CS/SeHNPs, and TMC/SeHNPs showed average hydrodynamic size of 78.8, 91.3, and 122 nm, and zeta potentials of −6.35 mV, +32.8 mV, and +54.8 mV, respectively. Biological assessments were conducted, including antibacterial and antibiofilm assays against clinical strains (E. coli , S. aureus , and K. pneumoniae), along with antioxidant activity. TMC/SeHNPs demonstrated superior performance compared to SeNPs and CS/SeHNPs with the lowest minimum inhibition concentrations (MIC) against S. aureus and K. pneumoniae (3.9 μg/mL) and 62.5 μg/mL against E. coli in addition to robust antibiofilm activity. Furthermore, the TMC/SeHNPs exhibited potent DPPH free radical scavenging ability and demonstrated good biocompatibility, as evidenced by cell viability assays on HFB4 cells. Overall, TMC/SeHNPs emerged as promising candidates in nanomedicine, offering high antioxidant, antibacterial, and antibiofilm activities alongside excellent biocompatibility. [Display omitted] [ABSTRACT FROM AUTHOR]

N,N,N -Trimethyl chitosan (TMC) is a quaternized chitosan with versatile biological features. However, low mechanical strength limits its uses, for example, as hydrogels for tissue engineering applications. This study illustrates a viable synthesis of metal/polymer hybrid, core-shell colloidal particles and their use as reinforcing and antioxidant fillers for TMC hydrogels. The core-shell particles were initially synthesized by surfactant-free emulsion polymerization, induced by a photo-redox initiating system of riboflavin assisted by a 3° amine and 2° alcohol co-initiators. The synthesized core-shell particles were based on two polymeric shells: TMC and chitosan, and two polymeric cores: poly (hydroxypropyl methacrylate) (PHPMA) and poly(2-hydroxy ethyl methacrylate) (PHEMA). The presence of both 3° amine on TMC and 2° alcohol on HPMA monomer enhanced the photopolymerization performance. The TMC-based particles had sizes of 122–154 nm and zeta potentials of 10–35 mV, bringing the colloidal stability in the 4–10 pH range. Furthermore, due to the presence of TMC on the shell layer, the core-shell particles could be used as templates to grow the Ag/Au bimetallic nanoparticles with alloy and core-shell types through a thermal reduction. The prepared hybrid particles were incorporated in TMC hydrogels as a multifunctional filler, improving their mechanical and antioxidant properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Oral delivery of therapeutic peptides has been a daunting challenge due to poor transport across the tight junctions and susceptibility to enzymatic degradation in the gastrointestinal tract. Numerous advancement in nanomedicine has been made for the effective delivery of protein and peptide. Owing to the superior performance of chitosan in opening intercellular tight junctions of epithelium and excellent mucoadhesive properties, chitosan-based nanocarriers have recently garnered considerable attention, which was formulated in this paper to orally deliver the GLP-1 drug (Exenatide). Against this backdrop, we used chitosan (CS) polymers to encapsulate the exenatide, sodium tripolyphosphate (TPP) as the cross-linking agent and coated the exterior with sodium alginate (ALG) to impart the stability in an acidic environment. The chitosan/alginate nanoparticles (CS-TPP-ALG) functioned as a protective exenatide carrier, realized efficient cellular uptake and controlled release, leading to a steady hypoglycemic effect and a good oral bioavailability in vivo. Trimethyl chitosan (TMC), a chitosan derivative with stronger positive electrical properties was additionally selected as a substitute for chitosan to construct the TMC-TPP-ALG nanoparticle, and its oral peptide delivery capacity was explored in terms of both characterization and pharmacodynamics studies. Overall, our study demonstrated that functional chitosan/alginate nanoparticles can protect proteins from enzymatic degradation and enhance oral absorption, which presents important research value and application prospects. [ABSTRACT FROM AUTHOR]

Preparation of drug delivery systems and nanomedicines necessitates the use of biocompatible excipients that are readily eliminated from the body. The systematic preclinical development of novel materials requires tools to evaluate their pharmacokinetics, biodistribution and excretion. Herein, we propose a technique called Size Exclusion of Radioactive Polymers (SERP) to trail the disposition of a radiolabeled polymer and its nanoparticles using chromatography in the presence of complex biological media such as blood, urine and feces. Trimethyl chitosan (TMC) is a polysaccharide of natural origin showing promise for controlled and targeted drug delivery applications. SERP was used to monitor degradation of radiolabeled TMC and its nanoparticles in vitro in the presence of strong acid, enzymes released by macrophages, as well as in vivo after administration to rats. Excretion of the radiolabeled TMC nanoparticles in urine and feces was monitored for 14 days after dosing to healthy rats, confirming that the polymer could be readily eliminated from the body. This work demonstrates the ability of SERP to understand the biological journey of biomaterials in vivo. Paving the way to understand the fate of polymers and nanoparticles in complex environments, the technique might facilitate the development of safer and better tolerated nanomedicines. Assessing safety of polymeric excipients and nanoparticles by measuring biodegradation and elimination in vitro and in vivo after intravenous injection using Size Exclusion of Radioactive Polymers (SERP). [Display omitted] • Size Exclusion of Radioactive Polymers (SERP) allows to monitor biodegradation. • SERP can be used in cell culture, in vivo and in excreta. • Trimethyl chitosan was degraded in vivo and excreted in urine and feces of rats. [ABSTRACT FROM AUTHOR]

The crucial challenge in tuberculosis (TB) as a chronic infectious disease is to present a novel vaccine candidate that improves current vaccination and provides efficient protection in individuals. The present study aimed to evaluate the immune efficacy of multi-subunit vaccines containing chitosan (CHT)- or trimethyl chitosan (TMC)-coated PLGA nanospheres to stimulate cell-mediated and mucosal responses against Mycobacterium Tuberculosis (Mtb) in an animal model. The surface-modified PLGA nanoparticles (NPs) containing tri-fusion protein from three Mtb antigens were produced by the double emulsion technique. The subcutaneously or nasally administered PLGA vaccines in the absence or presence of BCG were assessed to compare the levels of mucosal IgA, IgG1, and IgG2a production as well as secretion of IFN-γ, IL-17, IL-4, and TGF-β cytokines. According to the release profile, the tri-fusion encapsulated in modified PLGA NPs demonstrated a biphasic release profile including initial burst release on the first day and sustained release within 18 days. All designed PLGA vaccines induced a shift of Th1/Th2 balance toward Th1-dominant response. Although immunized mice through subcutaneous injection elicited higher cell-mediated responses relative to the nasal vaccination, the intranasally administered groups stimulated robust mucosal IgA immunity. The modified PLGA NPs using TMC cationic polymer were more efficient to elevate Th1 and mucosal responses in comparison with the CHT-coated PLGA nanospheres. Our findings highlighted that the tri-fusion loaded in TMC-PLGA NPs may represent an efficient prophylactic vaccine and can be considered as a novel candidate against TB. [ABSTRACT FROM AUTHOR]

This work deals with evaluating the hydrogel prepared from copper-crosslinked carboxymethyl cellulose as a controlled release system of fertilizer. In this respect, the behavior of gel was compared with gels prepared from polycationic biopolymer (trimethyl chitosan; Tri.M.Ch), individual or as a crosslinking agent of carboxylate-containing cellulose derivatives (CMC) and oxidized cellulose nanoparticles (OC.NPs). The swelling behavior of gel was preliminarily examined as a key factor for gel application. It is worth noting that the swelling capacity of CMC-Cu(II) gel was very higher (2350% at 250 min) than other gels (Tri.M.Ch, CMC-Tri.M.Ch andOC.NPs.Tri.M.Ch), where their swelling capacities ranged 100–300%. Moreover, it provided more sustained release rate of monoammonium phosphate (MAP-fertilizer) loaded hydrogels, similar toCMC-Tr.M.Ch, with maximum ~87–88%; while the gels of Tr.M.Ch. and Tr.M.Ch.-OC.NPs achieved maximum release reached 96–100%. The release of MAP from the hydrogels was followed by a Fickian or quasi-Fickian diffusion mechanism. The trend of hydrogels for MAP release was reflected in the nutrition value (NPK) of onion planted on gel-treated sand loamy soil. [ABSTRACT FROM AUTHOR]

This research aimed to study SiO2/quaternary-chitosan-coated magnetic material synthesis using the sol-gel method through two synthetic routes. The step of Route 1 was the methylation of the amine group on chitosan using methyl iodide and sodium hydroxide with dimethylformamide: water (1:1) as a solvent at room temperature for 48 hours to produce trimethyl chitosan. The next step was the sol-gel reaction. The magnetic was coated with silica and then added to the trimethyl chitosan solution that has reacted with (3-glycidyloxypropyl)trimethoxysilane as a crosslinker. Whereas Route 2 was the opposite of route 1, magnetic coating with chitosan silica was carried out first through the sol-gel reaction, followed by the methylation reaction. The synthesis results were characterized by their functional group, structure, crystal size, magnetic properties, and morphology. The Fe3O4/SiO2/quaternary-chitosan material was successfully synthesized, as indicated by the increase in the specific absorption band for C-H methyl and the decrease in the N-H amine absorption. Route 1 produced material with more quaternary ammonium groups and porous surface but inhomogeneous, while Route 2 produced thicker magnetic coatings. Both materials had stability in the range of pH 3-6 so that they could be applied as adsorbents for anionic compounds in this range. [ABSTRACT FROM AUTHOR]

The bacterium Burkholderia pseudomallei is the cause of melioidosis infectious disease. In this bacterium, the BLF1 protein wide inhibits the synthesis of proteins in human cells. This disease is reported to cause a death rate of 40% in some parts of the world. Currently, no effective vaccine is available against this bacterial infection. In this study, therefore, a Nano vaccine was synthesized based on the trimethyl chitosan (TMC) polymer containing the BLF1 recombinant protein, and its immunogenicity and protection in Syrian mice were evaluated by oral and subcutaneous injections. The BLF1 recombinant protein expression was induced in Escherichia coli Bl21 (DE3) and purified by the affinity chromatography technique. Recombinant protein-containing nanoparticles (NPs) were then synthesized by the ionotropic gelation method. After oral and subcutaneous injections, antibody titration was assessed by the indirect ELISA assay. Finally, murine groups were challenged using the BLF1 toxin. The results indicated that the immune system showed more antibody titration in subcutaneous injection than in the oral form. However, the results were reversed in the challenge results, and the survival rate was more significant in the oral injection. • Synthesis of BLF1-containing trimethyl chitosan nanoparticles and evaluation of its immunogenicity and protection in Syrian mice by oral and subcutaneous injections. • In this study, therefore, a Nano vaccine was synthesized based on the trimethyl chitosan (TMC) polymer containing the BLF1 recombinant protein, and its immunogenicity and protection in Syrian mice were evaluated by oral and subcutaneous injections. • The effect of TMC NP formulation on the BLF1 protein was compared through oral and subcutaneous methods. • The results of the challenge with the BLF1 toxin indicated that mice immunization by oral administration and injection with NPs plus the adjuvant produced proper protection (50% and 75%, respectively). • The results of ELISA and statistical analyses revealed that the antibody titer obtained from immunogenicity with the BLF1 protein was lower in the oral group than in the injection group, which was an expectable result. [ABSTRACT FROM AUTHOR]

Maliheh Hajiramezanali,1 Fatemeh Atyabi,2,3 Mona Mosayebnia,1 Mehdi Akhlaghi,4 Parham Geramifar,4 Amir Reza Jalilian,4 Seyed Mohammad Mazidi,5 Hassan Yousefnia,6 Soraya Shahhosseini,7 Davood Beiki4 1Department of Radiopharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 2Department of Pharmaceutical Nanotechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 3Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; 4Research Center for Nuclear Medicine, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran; 5Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran; 6Material and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran; 7Department of Radiopharmacy and Pharmaceutical Chemistry, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran Introduction: Nowadays, nanoparticles (NPs) have attracted much attention in biomedical imaging due to their unique magnetic and optical characteristics. Superparamagnetic iron oxide nanoparticles (SPIONs) are the prosperous group of NPs with the capability to apply as magnetic resonance imaging (MRI) contrast agents. Radiolabeling of targeted SPIONs with positron emitters can develop dual positron emission tomography (PET)/MRI agents to achieve better diagnosis of clinical conditions.Methods: In this work, N,N,N-trimethyl chitosan (TMC)-coated magnetic nanoparticles (MNPs) conjugated to S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (DOTA) as a radioisotope chelator and bombesin (BN) as a targeting peptide (DOTA–BN–TMC–MNPs) were prepared and validated using fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and powder X-ray diffraction (PXRD) tests. Final NPs were radiolabeled with gallium-68 (68Ga) and evaluated in vitro and in vivo as a potential PET/MRI probe for breast cancer (BC) detection.Results: The DOTA–BN–TMC–MNPs with a particle size between 20 and 30 nm were efficiently labeled with 68Ga (radiochemical purity higher than 98% using thin layer chromatography (TLC)). The radiolabeled NPs showed insignificant toxicity (>74% cell viability) and high affinity (IC50=8.79 µg/mL) for the gastrin-releasing peptide (GRP)-avid BC T-47D cells using competitive binding assay against 99mTc–hydrazinonicotinamide (HYNIC)–gamma-aminobutyric acid (GABA)–BN (7–14). PET and MRI showed visible uptake of NPs by T-47D tumors in xenograft mouse models.Conclusion: 68Ga–DOTA–BN–TMC–MNPs could be a potential diagnostic probe to detect BC using PET/MRI technique. Keywords: superparamagnetic iron oxide nanoparticles, trimethyl chitosan, bombesin, gallium-68, PET/MRI

The importance of developing more potent antimicrobials and robust infection prevention practices has been highlighted recently with the increase in reports of emerging bacterial resistance mechanisms and the development of antibiotic-resistant microbes. In this study, a quaternary ammonium chitosan derivative, N , N , N -trimethyl chitosan chloride (TMC) with inherent bactericidal property was synthesized and complexed with povidone‑iodine (PVP-I) to create a potentially more potent antiseptic solution that could also significantly enhance the wound healing process. TMC, a positively charged, water-soluble derivative of chitosan, formed stable solutions with PVP-I at 5% w / v TMC concentration (TMC5/PVP-I). TMC5/PVP-I was significantly effective against multidrug-resistant bacteria S. aureus compared with PVP-I alone. TMC/PVP-I solutions also showed fungicidal property against C. albicans , with no cytotoxic effects when tested against human fibroblast cells cultured in vitro. Wound healing assessment in vivo revealed early collagen formation and re-epithelialization for TMC5/PVP-I treated wounds in rats relative to control and PVP-I only. Formulation of TMC/PVP-I solutions presented in the study can be easily adapted in the existing production of commercial PVP-I creating a new product with more potent bactericidal and enhanced wound healing properties for optimal wound care. [ABSTRACT FROM AUTHOR]

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Blockade of the immune checkpoint PD-1/PD-L1 with monoclonal antibodies demonstrated unprecedented clinical efficacies in many cancers. But the orally available low molecular weight inhibitors remain infancy. Compared to small molecules, peptide exhibits better selectivity and fewer side effects, but poor half-life and a big challenge to be orally administrated. Here, we developed a proteolysis-resistant D peptide OPBP-1 (Oral PD-L1 Binding Peptide 1) which could selectively bind PD-L1, significantly block PD-1/PD-L1 interaction and enhance IFN-γ (interferon γ) secretion from CD8+ T cells in human PBMCs (Peripheral blood mononuclear cells). OPBP-1 could significantly inhibit tumor growth in murine colorectal CT26 and melanoma B16-OVA models at a relatively low dose of 0.5 mg/kg, with enhancing the infiltration and function of CD8+ T cells. More interestingly, oral delivery of OPBP-1 loaded TMC (N , N , N -trimethyl chitosan) hydrogel (OPBP-1@TMC) showed promising OPBP-1 oral bioavailability (52.8%) and prolonged half-life (14.55 h) in rats, and also significantly inhibited tumor growth in CT26 model. In conclusion, we discovered and optimized a PD-1/PD-L1 blocking peptide OPBP-1, and subsequently loaded into a TMC based hydrogel oral delivery system, in order to maximally elevate the oral bioavailability of the peptide drug and effectively inhibit tumor growth. These results opened up a new prospect for oral drug development in cancer immunotherapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Anshu Malik,* Manish Gupta,* Vatika Gupta, Himanshu Gogoi, Rakesh Bhatnagar Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India *These authors contributed equally to this work Abstract: The application of natural carbohydrate polysaccharides for antigen delivery and its adjuvanation potential has garnered interest in the scientific community in the recent years. These biomaterials are considered favorable candidates for adjuvant development due to their desirable properties like enormous bioavailability, non-toxicity, biodegradability, stability, affordability, and immunostimulating ability. Chitosan is the one such extensively studied natural polymer which has been appreciated for its excellent applications in pharmaceuticals. Trimethyl chitosan (TMC), a derivative of chitosan, possesses these properties. In addition it has the properties of high aqueous solubility, high charge density, mucoadhesive, permeation enhancing (ability to cross tight junction), and stability over a range of ionic conditions which makes the spectrum of its applicability much broader. It has also been seen to perform analogously to alum, complete Freund’s adjuvant, incomplete Freund’s adjuvant, and cyclic guanosine monophosphate adjuvanation, which justifies its role as a potent adjuvant. Although many review articles detailing the applications of chitosan in vaccine delivery are available, a comprehensive review of the applications of TMC as an adjuvant is not available to date. This article provides a comprehensive overview of structural and chemical properties of TMC which affect its adjuvant characteristics; the efficacy of various delivery routes for TMC antigen combination; and the recent advances in the elucidation of its mechanism of action. Keywords: trimethyl chitosan, chitosan, vaccine delivery, adjuvant, polymer

Increased expression of Hypoxia-inducible factor-1α (HIF-1α) in the tumor microenvironment, mainly due to tumor growth, plays a major role in the growth of cancer. Tumor cells induce the expression of cyclooxygenase 2 (COX2) and its product, prostaglandin E2 (PGE2), through overexpression of HIF-1α. It has been shown that ligation of PGE2 with its receptor, EP4, robustly promotes cancer progression. HIF-1α/COX2/PGE2/EP4 signaling pathways appear to play an important role in tumor growth. Therefore, we decided to block the expansion of cancer cells by blocking the initiator (HIF-1α) and end (EP4) of this pathway. In this study, we used hyaluronate (HA), and trimethyl chitosan (TMC) recoated superparamagnetic iron oxide nanoparticles (SPIONs) loaded with HIF-1α-silencing siRNA and the EP4 antagonist (E7046) to treat cancer cells and assessed the effect of combination therapy on cancer progression. The results showed that optimum physicochemical characteristics of NPs (size 126.9 nm, zeta potential 27 mV, PDI < 0.2) and linkage of HA with CD44 molecules overexpressed on cancer cells could deliver siRNAs to cancer cells and significantly suppress the HIF-1α in them. Combination therapy of cancer cells by using HIF-1α siRNA-loaded SPION-TMC-HA NPs and E7046 also prevent proliferation, migration, invasion, angiogenesis, and colony formation of the cancer cells, remarkably. • Hypoxia-mediated induction of HIF-1α in the tumor site enhances cancer progression. • Upregulation of PGE2 by HIF-1α in tumor region further promotes tumor growth. • Simultaneous inhibition of HIF-1α/EP4 receptor can be considered as a novel anti-cancer therapeutic approach. • SPION-TMC-HA NPs loaded with siRNA molecules are efficient nanocarriers for silencing HIF-1α/EP4 axis. [ABSTRACT FROM AUTHOR]

Fungal keratitis (FK) is a corneal infection caused by different fungal species. It is treated by the topical application of natamycin (NAT). Nevertheless, this approach faces many limitations like toxic effects, frequent dosing, resistance, and patient discomfort. The present research reports the development of trimethyl chitosan (TMC) coated mucoadhesive cationic niosomes by a modified thin-film hydration method. TMC was synthesized using a one-step carbodiimide method and characterized by 1H-NMR and degree of quaternization (53.74 ± 1.06%). NAT, cholesterol (CHOL), span 60 (Sp60), and dicetyl phosphate (DCP) were used to prepare niosomes which were incubated with TMC to obtain mucoadhesive cationic NAT loaded niosomes (MCNNs). MCNNs showed a spherical shape with 1031.12 ± 14.18 nm size (PDI below 0.3) and 80.23 ± 5.28% entrapment efficiency. In vitro drug release studies showed gradual drug release from TMC coated niosomes as compared to the uncoated niosomes. MIC assay and disk diffusion assay revealed promising in vitro antifungal potential of MCNNs similar to the marketed formulation. For investigating in vivo performance, ocular retention and pharmacokinetics, ocular irritation, and ulcer healing studies were performed using the rabbit model. Mucoadhesive property and prolonged local drug release improved the safety and efficacy of NAT, suggesting that the developed niosomes could be an emerging system for effective treatment of fungal keratitis. [ABSTRACT FROM AUTHOR]

There is an interconnected network between S1P/sphingosine‐1‐phosphate receptor 1 (S1PR1), IL‐6/glycoprotein 130 (GP130), and signal transducer and activator of transcription 3 (STAT3) signaling pathways in the tumor microenvironment, which leads to cancer progression. S1P/S1PR1 and IL‐6/GP130 signaling pathways phosphorylate and activate STAT3, and it then induces the expression of S1PR1 and interleukin‐6 (IL‐6) in a positive feedback loop leading to cancer progression. We hypothesized that blockade of this amplification loop can suppress the growth and development of cancer cells. Therefore, we silenced STAT3 upstream molecules including the S1PR1 and GP130 molecules in cancer cells using small interfering RNA (siRNA)‐loaded alginate‐conjugated trimethyl chitosan (ATMC) nanoparticles (NPs). The generated NPs had competent properties including the appropriate size, zeta potential, polydispersity index, morphology, high uptake of siRNA, high rate of capacity, high stability, and low toxicity. We evaluated the effects of siRNA loaded ATMC NPs on tumor hallmarks of three murine‐derived cancer cell lines, including 4T1 (breast cancer), B16‐F10 (melanoma), and CT26 (colon cancer). The results confirmed the tumor‐suppressive effects of combinational targeting of S1PR1 and GP130. Moreover, combination therapy could potently suppress tumor growth as assessed by the chick chorioallantoic membrane assay. In this study, we targeted this positive feedback loop for the first time and applied this novel combination therapy, which provides a promising approach for cancer treatment. The development of a potent nanocarrier system with ATMC for this combination was also another aspect of this study, which should be further investigated in cancer animal models in further studies. [ABSTRACT FROM AUTHOR]

Purpose: Hypoxia-inducible factor (HIF) is one of the critical components of the tumor microenvironment that is involved in tumor development. HIF-1α functionally and physically interacts with CDK1, 2, and 5 and stimulates the cell cycle progression and Cyclin-Dependent Kinase (CDK) expression. Therefore, hypoxic tumor microenvironment and CDK overexpression lead to increased cell cycle progression and tumor expansion. Therefore, we decided to suppress cancer cell expansion by blocking HIF-1α and CDK molecules. Methods: In the present study, we used the carboxylated graphene oxide (CGO) conjugated with trimethyl chitosan (TMC) and hyaluronate (HA) nanoparticles (NPs) loaded with HIF-1α-siRNA and Dinaciclib, the CDK inhibitor, for silencing HIF-1α and blockade of CDKs in CD44-expressing cancer cells and evaluated the impact of combination therapy on proliferation, metastasis, apoptosis, and tumor growth. Results: The results indicated that the manufactured NPs had conceivable physicochemical properties, high cellular uptake, and low toxicity. Moreover, combination therapy of cancer cells using CGO-TMC-HA NPs loaded with HIF-1α siRNA and Dinaciclib (SCH 727965) significantly suppressed the CDKs/HIF-1α and consequently, decreased the proliferation, migration, angiogenesis, and colony formation in tumor cells. Conclusions: These results indicate the ability of CGO-TMC-HA NPs for dual drug/gene delivery in cancer treatment. Furthermore, the simultaneous inhibition of CDKs/HIF-1α can be considered as a novel anti-cancer treatment strategy; however, further research is needed to confirm this treatment in vivo. [ABSTRACT FROM AUTHOR]

To improve ocular bioavailability of baicalein (BAI), trimethyl chitosan coated lipid nanoparticles of baicalein (TMC-BAI-LNPs) were prepared, optimized and characterized. The properties of TMC-BAI-LNPs such as morphology, particle size, zeta potential and fourier transform infrared spectroscopy were investigated. Additionally, molecular dynamics simulation was applied as a new method to evaluate drug-biological membrane interactions. Transmission electron microscopy showed that the LNPs were approximately spherical in shape with a smooth surface. TMC-BAI-LNPs had a particle size of 162.8 nm, a positive surface charge with a zeta potential of 26.6 mV. The entrapment efficiency and drug loading values of BAI in the formulation were 90.65% and 2.04%, respectively. Moreover, in vitro drug release revealed that TMC-BAI-LNPs had a sustained release effect. In vivo studies indicated TMC-BAI-LNPs had no ocular irritation and the AUC of TMC-BAI-LNPs was 3.17-fold than that of the control (p < 0.01). Molecular dynamics simulation data showed that BAI had a poor membrane permeability, which limited the ocular bioavailability. The results indicated that TMC-BAI-LNPs might open up a new avenue for ocular administration. Furthermore, molecular dynamics simulation could predict permeability of drugs. Unlabelled Image • TMC coated lipid nanoparticles of baicalein (TMC-BAI-LNPs) were prepared. • MD simulation was used as a novel method to evaluate TMC-BAI-LNPs. • TMC has been approved for biocompatibility and used as ophthalmic delivery system. • MD simulation showed BAI had a poor membrane permeability, which limited the ocular bioavailability. • TMC-BAI-LNPs have a great potential for ocular administration. [ABSTRACT FROM AUTHOR]

The immunosuppressive nature of the tumor microenvironment is a critical problem that should be considered before the design of immunotherapies. Interleukin (IL)-6 and its related downstream molecules such as signal transducer and activator of transcription (STAT)3 play an important role in the cancer progression, which can be considered as potential therapeutic targets. In the present study, we generated the active-targeted hyaluronate (HA) recoated N , N , N -trimethyl chitosan (TMC) nanoparticles (NPs) to deliver IL-6- and STAT3-specific small interfering RNAs (siRNAs) to the CD44-expressing cancer cells. We utilized the interaction between HA and CD44 to increase the specificity and efficacy of cellular uptake in NPs. The results showed that the synthesized NPs had efficient physicochemical characteristics, high transfection efficiency, low toxicity, and controlled siRNA release. siRNA-loaded NPs significantly inhibited the IL-6/STAT3 expression, which was associated with blockade of proliferation, colony formation, migration, and angiogenesis in cancer cells. These findings imply the potential of HA-TMC NPs as potent vectors in gene therapy and their application for the silencing of IL-6 and STAT3, as a novel anti-cancer combination therapeutic strategy, for the first time. • Hyaluronate recoating of trimethyl chitosan increased cellular uptake and stability of them. • IL-6- and STAT3-siRNA loaded HA-TMC NPs effectively downregulate IL-6/STAT3 axis. • IL-6/STAT3 axis silencing significantly inhibited cancer cells progression and development. [ABSTRACT FROM AUTHOR]

Recent advancements in wound care have led to the development of interactive wound dressings utilizing nanotechnology, aimed at enhancing healing and combating bacterial infections while adhering to established protocols. Our novel wound dressings consist of N , N , N -trimethyl chitosan capped gold‑silver nanoparticles (Au-Ag-TMC-NPs), with a mean size of 108.3 ± 8.4 nm and a zeta potential of +54.4 ± 1.8 mV. These optimized nanoparticles exhibit potent antibacterial and antifungal properties, with minimum inhibitory concentrations ranging from 0.390 μg ml−1 to 3.125 μg ml−1 and also exhibited promising zones of inhibition against multi-drug resistant strains of S. aureus , E. coli , P. aeruginosa , and C. albicans. Microbial transmission electron microscopy reveals substantial damage to cell walls and DNA condensation post-treatment. Furthermore, the nanoparticles demonstrate remarkable inhibition of microbial efflux pumps and are non-hemolytic in human blood. Incorporated into polyvinyl alcohol/chitosan nanofibers, they form Au-Ag-TMC-NPs-NFs with diameters of 100–350 nm, facilitating efficient antimicrobial wound dressing. In vivo studies on MDR microbial-infected wounds in mice showed 99.34 % wound healing rate within 12 days, corroborated by analyses of wound marker protein expression levels and advanced imaging techniques such as ultrasound/photoacoustic imaging, providing real-time visualization and blood flow assessment for a comprehensive understanding of the dynamic wound healing processes. [Display omitted] [ABSTRACT FROM AUTHOR]

Morteza Abkar,1 Mahdi Fasihi-Ramandi,2 Hamid Kooshki,3 Abbas Sahebghadam Lotfi4 1Nanomedicine and Nanobiology Research Center, Shiraz University of Medical Sciences, Shiraz, 2Molecular Biology Research Center, 3Nanobiotechnology Research Center, Baqiyatallah University of Medical Sciences, 4Department of Clinical Biochemistry, Faculty of Medicine, Tarbiat Modares University, Tehran, Iran Abstract: Brucellosis is a group of closely associated zoonotic bacterial illnesses caused by members of the genus Brucella. B. melitensis Omp31 is a promising candidate for a subunit vaccine against brucellosis. This study surveyed the immunogenicity of Omp31 alone and with incomplete Freund’s adjuvant (Omp31-IFA) and N-trimethyl chitosan (TMC/Omp31) nanoparticles (NPs), as well as the effect of Omp31 immunization route on immunological responses and protection. After expression and purification, the recombinant Omp31 (rOmp31) was loaded onto TMC NPs by ionic gelation. The particle size, loading efficiency and in vitro release of the NPs were examined. Omp31-IFA was administered intraperitoneally, while TMC/Omp31 NPs were administered orally and intraperitoneally. According to the antibody subclasses and cytokine profile, intraperitoneal immunization by Omp31-IFA and TMC/Omp31 NPs induced T helper 1 (Th1) and Th1–Th2 immune responses, respectively. On the other hand, oral immunization with TMC/Omp31 NPs elicited a mixed Th1–Th17 immune response. Data obtained from the cell proliferation assay showed that vaccination with Omp31 stimulated a vigorous antigen-specific cell proliferative response, which could be further increased after oral immunization with TMC/Omp31 NPs. Vaccinated groups of mice when challenged with B. melitensis 16M were found to be significantly protected in the orally administered group in comparison with the intraperitoneally immunized mice. Results of this study indicated that the reason for high protection after oral vaccination can be via elicited Th17 response. Keywords: brucellosis, Th17, trimethyl chitosan, vaccine, nanoparticle

Background and purpose: In recent years nanotechnology has a significant impact on various fields of human life, especially in pharmaceutical and medical needs. Some biopolymers such as chitosan which is also biocompatible are low cost and abundantly found, so, their application for vaccine production is cost benefit. Trimethyl chitosan is a deacetylated derivative of chitosan that could be used to increase the induction of immune response. In this study, trimethyl chitosan nanoparticles containing tetanus protein were used to stimulate the immune system. Materials and methods: In this experimental study, synthesis of the tetanus toxoid loaded nanoparticles was done by ion gelation method. Physical features of the nanoparticles were investigated using scanning electron microscopy (SEM). The nanoparticles were then injected subcutaneously into mice. After the sampling process, the immune system stimulation was evaluated using indirect ELISA. Data was analyzed using one-way ANOVA and significance level of P< 0.05. Results: The purity of protein was confirmed by SDS-PAGE and encapsulated proteins were loaded up to 80 percent. ELISA results showed that the immune system was stimulated significantly compared with Freund adjuvant, and antibody titer increased. Conclusion: Tetanus toxoid loaded Trimethyl chitosan nanoparticles increase the stimulation of immune system and are more effective in comparison with Freund's adjuvant.

Gene therapy, including small interfering RNA (siRNA) technology, is one of the leading strategies that help to improve the outcomes of the current therapeutic systems against HIV‐1 infection. The successful therapeutic application of siRNAs requires their safe and efficient delivery to specific cells. Here, we introduce a superparamagnetic iron oxide nanoparticle (SPION) for delivering siRNA against HIV‐1 nef (anti‐nef siRNA) into two cell lines, HEK293 and macrophage RAW 264.7. SPIONs were coated with trimethyl chitosan (TMC), and thereafter, different concentrations of SPION–TMC were coated with different ratios of a carboxymethyl dextran (CMD) to modify the physicochemical properties and improve the biological properties of the nanocarriers. The nanoparticles exhibited a spherical shape with an average size of 112 nm. The obtained results showed that the designed delivery route enhanced the uptake of siRNA into both HEK293 and RAW 264.7 cells compared with control groups. Moreover, CMD–TMC–SPIONs containing anti‐nef siRNA significantly reduced the expression of HIV‐1 nef in HEK293 stable cells. The modified siRNA‐loaded SPIONs also displayed no toxicity or apoptosis‐inducing effects on the cells. The CMD–TMC–SPIONs are suggested as potential nanocarriers for siRNA delivery in gene therapy of HIV‐1 infection. [ABSTRACT FROM AUTHOR]

Short peptides derived from virulent pathogen proteins are promising antigens for the development of vaccines against infectious diseases. However, in order to mimic the danger signals associated with natural infection and stimulate an adaptive immune response, peptide antigens must be co-delivered with immune adjuvants. In this study, a group A streptococcus (GAS) M-protein derived B-cell epitope: J8, and universal T-helper epitope P25 containing peptides, were chemically coupled with different anionic amino acid-based polymers. The poly(anionic amino acid)-peptide antigen conjugates were mixed with trimethyl chitosan (TMC) to produce self-adjuvanting nanoparticulate vaccine candidates. TMC from two different sources were used to analyse their effect on immunogenicity. The nanoparticles produced from a peptide modified with 10 residues of polyglutamic acid and fungal TMC (NP5) stimulated production of the highest levels of serum antibodies in outbred mice. These antibodies were opsonic against all clinical GAS isolates tested. [ABSTRACT FROM AUTHOR]

Purpose: A major challenge in ocular therapeutics is poor bioavailability of drug, 1% or even less of the instilled dose is absorbed and frequent administration of conventional products leads to poor adherence to therapy. Hence, the present study is to synthesize N-trimethyl chitosan (TMC), a water-soluble chitosan derivative and to prepare flurbiprofen (FLU):hydroxyl propyl-β-cyclodextrin (HP-β-CD) complex-loaded nanoparticles for treatment of bacterial conjunctivitis which aims to increase the residence time in ocular tissue, thus enhancing patient compliance and improved efficacy. Methods: TMC was synthesized and characterized by 1H NMR and FT-IR. TMC and chitosan (CS) nanoparticles containing inclusion complex were prepared by ionic gelation using sodium tripolyphosphate (TPP). The nanoparticles thus obtained were evaluated for particle size, zeta potential, drug entrapment, in-vitro release, in-vitro mucoadhesion, and TEM for morphology and irritation potential was evaluated by the HET-CAM technique. Results: N-methyl quaternization of CS was confirmed by 1H NMR. The particle size and zeta potential of the TMC nanoparticles were found to be 201 ± 1.55 nm and +13.9 ± 1.697 mV and that of CS nanoparticles were 361.2 ± 1.55 nm and +10.9 ± 0.424 mV, respectively. The entrapment of FLU- HP-β-CD inclusion complex in polymeric nanoparticles was found to be 10.91 ± 1.541%. The observed in-vitro release profile of TMC nanoparticles indicated characteristic burst release followed by delayed release. HET-CAM studies demonstrated the ocular safety of TMC nanoparticles. Conclusion: The developed TMC nanoparticles offered prolonged release potential for transmucosal ocular delivery of hydrophobic flurbiprofen. [ABSTRACT FROM AUTHOR]

Abstract Oral administration is a highly attractive approach for the delivery of protein drugs. However, oral protein therapeutics typically exhibit extremely poor bioavailability due to the harsh gastrointestinal (GI) environments and low permeability of protein across the intestinal barrier. Trimethyl chitosan (TMC) shows excellent mucoadhesive and absorption-enhancing properties while fucoidan (FD) has hypoglycemic effects and can prevent diabetes-related complications. Here we report, for the first time, that TMC combined with FD can be developed to a mutlifunctional nanoplatform for enhancing the transepithelial permeation of insulin through the intestinal epithelial cell barrier and inhibiting the α-glucosidase activity. TMC and FD self-assembled into spherical nanoparticles (NPs) for insulin encapsulation. TMC/FD NPs protected insulin against degradation by releasing insulin in a pH-dependent manner in the gastrointestinal tract fluids. The NPs were able to modulate the barrier function of the Caco-2 intestinal epithelial cell monolayer, and enhance paracellular transport of insulin across the intestinal barrier. TMC/FD NPs also showed α-glucosidase inhibitory activity, with an inhibition ratio of 33.2% at 2 mg/mL. The superior transepithelial absorption enhancing property of the TMC/FD NPs is expected to combine in the future with the functions of fucoidan against diabetes-related complications for development of advanced mutlifunctional therapeutic platforms for diabetes. [ABSTRACT FROM AUTHOR]

For efficient mucosal vaccine delivery, nanoparticulate antigens are better taken by microfold cells in the nasal associated lymphoid tissue and also dendritic cells. Nanoparticles based on polymers such as chitosan (CHT) and its water soluble derivative, trimethylchitosan (TMC), could be successfully used as carrier/adjuvant for this purpose. Sodium alginate, a negatively charged biopolymer, could modify the immunostimulatory properties of CHT and TMC NPs and increase their stability. Sodium alginate (ALG)-coated chitosan (CHT) and trimethylchitosan (TMC) nanoparticles (NPs) loaded with inactivated PR8 influenza virus were successfully prepared by direct coating of the virus with CHT or TMC polymers to evaluate their immunoadjuvant potential after nasal immunization. After nasal immunizations in BALB/c mice, PR8-CHT formulation elicited higher IgG2a and IgG1 antibody titers compared with PR8-TMC. ALG coating of this formulation (PR8-CHT-ALG) significantly decreased the antibody titers and a less immune response was induced than PR8-TMC-ALG formulation. PR8-TMC-ALG formulation showed significantly higher IgG2a/IgG1 ratio, as criteria for Th1-type immune response, compared with PR8-CHT-ALG and PR8 virus alone. Altogether, the PR8-TMC-ALG formulation could be considered as an efficient intranasal antigen delivery system for nasal vaccines. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Peptide-based vaccines have the potential to overcome the limitations of classical vaccines; however, their use is hampered by a lack of carriers and adjuvants suitable for human use. In this study, an efficient self-adjuvanting peptide vaccine delivery system was developed based on the ionic interactions between cationic trimethyl chitosan (TMC) and a peptide antigen coupled with synthetically defined anionic α-poly-(l -glutamic acid) (PGA). The antigen, possessing a conserved B-cell epitope derived from the group A streptococcus (GAS) pathogen and a universal T-helper epitope, was conjugated to PGA using cycloaddition reaction. The produced anionic conjugate formed nanoparticles (NP-1) through interaction with cationic TMC. These NP-1 induced higher systemic and mucosal antibody titers compared to antigen adjuvanted with standard mucosal adjuvant cholera toxin B subunit or antigen mixed with TMC. The produced serum antibodies were also opsonic against clinically isolated GAS strains. Further, a reduction in bacterial burden was observed in nasal secretions, pharyngeal surface and nasopharyngeal-associated lymphoid tissue of mice immunized with NP-1 in GAS challenge studies. Thus, conjugation of defined-length anionic polymer to peptide antigen as a means of formulating ionic interaction-based nanoparticles with cationic polymer is a promising strategy for peptide antigen delivery. Statement of Significance A self-adjuvanting delivery system is required for peptide vaccines to enhance antigen delivery to immune cells and generate systemic and mucosal immunity. Herein, we developed a novel self-adjuvanting nanoparticulate delivery system for peptide antigens by combining polymer-conjugation and complexation strategies. We conjugated peptide antigen with anionic α-poly-(l -glutamic acid) that in turn, formed nanoparticles with cationic trimethyl chitosan by ionic interactions, without using external crosslinker. On intranasal administration to mice, these nanoparticles induced systemic and mucosal immunity, at low dose. Additionally, nanoparticles provided protection to vaccinated mice against group A streptococcus infection. Thus, this concept should be particularly useful in developing nanoparticles for the delivery of peptide antigens. [ABSTRACT FROM AUTHOR]

Brucella (B) species are brucellosis causative agents, a worldwide zoonotic illness causing Malta fever in humans and abortion in domestic animals. In this work, we evaluated the vaccine potential of Trimethyl chitosan (TMC) nanoparticles formulation of Urease (TMC/Urease) against brucellosis. TMC/Urease nanoparticles and urease without any adjuvant were separately administered both orally and intraperitoneally. Intraperitoneal (i.p.) administration of urease alone as well as oral administration of both TMC/Urease nanoparticles and urease alone, elicited low titers of specific immunoglobulin G (IgG), while i.p. immunization with TMC/Urease nanoparticles induced high specific IgG production levels. As it was indicated by the cytokine assay and the antibody isotypes, i.p. immunization by urease alone, and TMC/Urease nanoparticles induced a mixed Th1-Th2 immune response, whereas oral administration of both urease alone and TMC/Urease nanoparticles induced a mixed Th1-Th17 immune response. In lymphocyte proliferation assay, spleen cells from i.p.-vaccinated mice with TMC/Urease nanoparticles showed a strong recall proliferative response. Vaccinated animals were challenged with virulent strains of B. melitensis and B. abortus . I.p. vaccination with TMC/Urease nanoparticles resulted in a high degree of protection. Altogether, our results indicated that TMC nanoparticles are a potent delivery system for i.p.-administered Brucella antigens. [ABSTRACT FROM AUTHOR]

Brain tumor has a low prognosis with only 15% survival rate (5 years after diagnosis). Many of the current therapeutics have limited activity due to their inability to cross the blood brain barrier which retards drug accumulation in tumor site and causes drug resistance. Piperine, a phytochemical drug with poor solubility, could be an alternative to current therapeutics after evading its solubility and permeability limitations. Piperine micellization was optimized to improve drug solubility. Positively charged trimethyl-chitosan was synthesized then electrostatically adsorbed onto piperine nanomicelles forming core-shell nanoparticles. Physicochemical and morphological characterizations, and in-vitro release were performed. Cytotoxicity on human brain cancer cell line (Hs683) was evaluated using IC50 determination, cell cycle arrest analysis, apoptosis and enzyme-linked immunosorbent assay. Optimum piperine-loaded core-shell nanoparticles were successfully fabricated with double-phase release model. Significant improvement in cytotoxicity than free drug was noted with increasing in G2/M-phase and pre-GI-phase population, apoptotic/necrotic rates and inhibition of CDK2a. [ABSTRACT FROM AUTHOR]

Silibinin is a natural flavonoid with a strong antioxidant property and weak cytotoxic activity. It has demonstrated anti-tumoural activity against many types of malignancies; however, due to its hydrophobic structure, it has poor water solubility, bioavailability and permeability across intestinal epithelial cells. To improve the effect of silibinin, we have vehiculated silibinin by a highly stable niosomal nanostructure based on a Span 60/cholesterol (CH)/N-trimethyl chitosan (TMC) system in order to study its potential application for the delivery of silibinin in T47D cultured under three-dimensional (3D) and two-dimensional (2D) conditions. To study the effect of nanodrug on miRNAs expression, we evaluated quantitative expression of miRNA-21 and miRNA-15a as well as miR-141 and miR-200c which act as oncogene and tumour suppressors by real-time PCR. Results demonstrated that the mechanism of nanodrug action as well as the response of tumour cells differed in 3D culture as compared to 2D. Delivery of silibinin-loaded niosomes coated with TMC was found to be more effective in inhibiting the growth of tumour cells and inducing apoptosis than free silibinin administration. In silibinin‐treated cells, death occurred in a dose- and time- dependent manner by induction of apoptosis and alteration of the cell cycle. Real-time PCR analysis revealed a decrease in miR-21, miR-15a and miR-141while increase in miR-200c expression levels was observed in silibinin-treated cells relative to the levels in the untreated cells. The results show that nanodrug delivery was more effective than free silibinin administration in changing the level of miRNAs expression in cancer cells. Therefore, niosomal nanostructure with TMC could be a suitable vehicle for hydrophobic compounds, such as silibinin, by improving their action in cancer therapy. [ABSTRACT FROM AUTHOR]

The aim of the study was to encapsulate resveratrol (RV) in trimethyl chitosan (TMC) nanoparticles cross-linked with tripolyphosphate (TPP) and/or alginate to achieve controlled release and improved cellular uptake. TMC (degree of quaternization of 78%) was prepared by reacting purified chitosan with iodomethane. Three types of RV-loaded TMC nanoparticles were prepared: TMC-TPP (TP-NPs), TMC-alginate (TA-NPs), and TMC-alginate-TPP (TAP-NPs). TA-NPs and TAP-NPs showed lower particle size and encapsulation efficiency (EE), better distribution, and more sustained release than TP-NPs due to the high molecular weight and viscous property of alginate. Caco-2 cellular uptake of RV was improved by TMC nanoencapsulation, and TP-NPs showed the highest uptake due to its significantly higher EE. Compared with TAP-NPs, TA-NPs with higher positive surface charge showed higher cellular uptake. Moreover, Caco-2 cell growth-inhibiting activity of RV was significantly increased by TMC nanoencapsulation and TP-NPs showed the significantly highest activity with a good agreement with the permeability results. [ABSTRACT FROM AUTHOR]

Mucoadhesive drug delivery systems are desirable as they can increase the residence time of drugs at the site of absorption/action, provide sustained drug release and minimize the degradation of drugs in various body sites. Chitosan is a cationic polysaccharide that exhibits mucoadhesive properties and it has been widely used in the design of mucoadhesive dosage forms. However, its limited mucoadhesive strength and limited water-solubility at neutral and basic pHs are considered as two major drawbacks of its use. Chemical modification of chitosan has been exploited to tackle these two issues. In this review, we highlight the up-to-date studies involving the synthetic approaches and description of mucoadhesive properties of chitosan and chitosan derivatives. These derivatives include trimethyl chitosan, carboxymethyl chitosan, thiolated chitosan, chitosan-enzyme inhibitors, chitosan-ethylenediaminetetraacetic acid (chitosan-EDTA), half-acetylated chitosan, acrylated chitosan, glycol chitosan, chitosan-catechol, methyl pyrrolidinone-chitosan, cyclodextrin-chitosan and oleoyl-quaternised chitosan. We have particularly focused on the effect of chemical derivatization on the mucoadhesive properties of chitosan. Additionally, other important properties including water-solubility, stability, controlled release, permeation enhancing effect, and in vivo performance are also described. [ABSTRACT FROM AUTHOR]

N-selective derivatives of chitosan (CH) namely, N -methyl chitosan (NMC), trimethyl chitosan (TMC), diethyl methyl chitosan (DEMC) and carboxymethyl chitosan (CMC) were synthesized to study the effects of alkylation on antimicrobial property and biocompatibility. The derivatives were characterized by FT-IR confirming O-free alkyl substitution. XRD studies showed reduction in crystallinity and zeta potential measurement proved the increase in positive charges upon alkylation. Antimicrobial activity was observed to be in the order of DEMC < CMC < CH < NMC < TMC. MTT assay revealed that the modified chitosans were non-cytotoxic to primary normal human epidermal keratinocytes. Chitosan derivatives were tested using EpiDerm™ Skin Irritation Test as per OECD TG 439 and were categorized as non-irritants. Zebrafish embryo viability test was used to study the toxicity of the modified chitosans and LC 50 for the samples in zebrafish embryo ranged from 20 to 50 μg/mL. Results showed that amongst the alkyl derivatives, O -methyl free N,N,N–trimethyl chitosan (TMC) is the potential candidate material with enhanced antimicrobial property and biocompatibility. Herein, we report the first results of using chitosan or its derivatives in the EpiDerm in vitro skin irritation test. The four derivatives of chitosan are compared on a single platform for their physicochemical, biological and biocompatible properties. [ABSTRACT FROM AUTHOR]

N,N,N-Trimethyl chitosan (TMC) is one chitosan derivative that, because of its improved solubility, has been studied for industrial and pharmaceutic applications. Conventional methods for the synthesis of TMC involve the use of highly toxic and harmful reagents, such as methyl iodide and dimethyl sulfate (DMS). Although the methylation of dimethylated chitosan to TMC by dimethyl carbonate (DMC, a green and benign methylating agent) was reported recently, it involved a formaldehyde-based procedure. In this paper we report the single-step synthesis of TMC from chitosan using DMC in an ionic liquid. The TMC synthesised was characterised by 1H NMR spectroscopy and a functionally meaningful degree of quaternisation of 9% was demonstrated after a 12-h reaction time.

The presence of several organic contaminants in the environment and aquatic compartments has been a matter of great concern in the recent years. To tackle this problem, new sustainable and cost-effective technologies are needed. Herein we describe magnetic biosorbents prepared from trimethyl chitosan (TMC), which is a quaternary chitosan scarcely studied for environmental applications. Core@shell particles comprising a core of magnetite (Fe3O4) coated with TMC/siloxane hybrid shells (Fe3O4@SiO2/SiTMC) were successfully prepared using a simple one-step coating procedure. Adsorption tests were conducted to investigate the potential of the coated particles for the magnetically assisted removal of the antibiotic sulfamethoxazole (SMX) from aqueous solutions. It was found that TMC-based particles provide higher SMX adsorption capacity than the counterparts prepared using pristine chitosan. Therefore, the type of chemical modification introduced in the chitosan type precursors used in the surface coatings has a dominant effect on the sorption efficiency of the respective final magnetic nanosorbents.