Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30.813
Filtrar
1.
J Vet Sci ; 25(2): e30, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38568831

RESUMO

BACKGROUND: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. OBJECTIVES: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. METHODS: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. RESULTS: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. CONCLUSIONS: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.


Assuntos
Quitosana , Nanopartículas , Animais , Staphylococcus epidermidis/genética , Nanogéis , Gelatina/farmacologia , Quercetina/farmacologia , Biofilmes , Quitosana/farmacologia , Quitosana/química , Gelatinases/farmacologia , Antibacterianos/farmacologia
2.
PLoS One ; 19(4): e0292414, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38568898

RESUMO

To mitigate the risk of radioactive isotope dissemination, the development of preventative and curative measures is of particular interest. For mass treatment, the developed solution must be easily administered, preferably orally, with effective, nontoxic decorporating properties against a wide range of radioactive isotopes. Currently, most orally administered chelation therapy products are quickly absorbed into the blood circulation, where chelation of the radioactive isotope is a race against time due to the short circulation half-life of the therapeutic. This report presents an alternative therapeutic approach by using a functionalized chitosan (chitosan@DOTAGA) with chelating properties that remains within the gastrointestinal tract and is eliminated in feces, that can protect against ingested radioactive isotopes. The polymer shows important in vitro chelation properties towards different metallic cations of importance, including (Cs(I), Ir(III), Th(IV), Tl(I), Sr(II), U(VI) and Co(II)), at different pH (from 1 to 7) representing the different environments in the gastrointestinal tract. An in vivo proof of concept is presented on a rodent model of uranium contamination following an oral administration of Chitosan@DOTAGA. The polymer partially prevents the accumulation of uranium within the kidneys (providing a protective effect) and completely prevents its uptake by the spleen.


Assuntos
Quitosana , Protetores contra Radiação , Urânio , Quitosana/química , Urânio/química , Protetores contra Radiação/farmacologia , Polímeros , Quelantes/química
3.
PLoS One ; 19(4): e0298117, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38573916

RESUMO

Selection of adjuvant to be combined with the antigen is an extremely important point for formulating effective vaccines. The aim of this study was to evaluate reactogenicity, levels of IgM, IgG and subclasses (IgG1, IgG2b and IgG3), and protection elicited by vaccine formulations with association of chitosan coated alginate or Montanide ISA 61 with γ-irradiated Brucella ovis. The alginate/chitosan biopolymers as well as the Montanide ISA 61 emulsion elicited intense and long-lasting local response, especially when associated with the antigen. However, Montanide ISA 61 induced less intense reactogenicity when compared to alginate/chitosan. Furthermore, γ-irradiated B. ovis with Montanide ISA 61 induced higher levels of IgG2b an important marker of cellular immune response. In conclusion, Montanide ISA 61 resulted in milder reactogenicity when compared to the alginate/chitosan, while it induced a high IgG2b/IgG1 ratio compatible with a Th1 profile response.


Assuntos
Quitosana , Óleo Mineral , Vacinas , Animais , Camundongos , Ovinos , Adjuvantes de Vacinas , Cápsulas , Adjuvantes Imunológicos/farmacologia , Imunoglobulina G , Camundongos Endogâmicos BALB C
4.
Curr Microbiol ; 81(5): 125, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38558085

RESUMO

More than half of the world's population is infected with Helicobacter pylori (H. pylori), which may lead to chronic gastritis, peptic ulcers, and stomach cancer. LeoA, a conserved antigen of H. pylori, aids in preventing this infection by triggering specific CD3+ T-cell responses. In this study, recombinant plasmids containing the LeoA gene of H. pylori are created and conjugated with chitosan nanoparticle (CSNP) to immunize BALB/c mice against the H. pylori infection. We used the online Vaxign tool to analyze the genomes of five distinct strains of H. pylori, and we chose the outer membrane as a prospective vaccine candidate. Afterward, the proteins' immunogenicity was evaluated. The DNA vaccine was constructed and then encapsulated in CSNPs. The effectiveness of the vaccine's immunoprotective effects was evaluated in BALB/c mice. Purified activated splenic CD3+ T cells are used to test the anticancer effects in vitro. Nanovaccines had apparent spherical forms, were small (mean size, 150-250 nm), and positively charged (41.3 ± 3.11 mV). A consistently delayed release pattern and an entrapment efficiency (73.35 ± 3.48%) could be established. Compared to the non-encapsulated DNA vaccine, vaccinated BALB/c mice produced higher amounts of LeoA-specific IgG in plasma and TNF-α in splenocyte lysate. Moreover, BALB/c mice inoculated with nanovaccine demonstrated considerable immunity (87.5%) against the H. pylori challenge and reduced stomach injury and bacterial burdens in the stomach. The immunological state in individuals with GC with chronic infection with H. pylori is mimicked by the H. pylori DNA nanovaccines by inducing a shift from Th1 to Th2 in the response. In vitro human GC cell development is inhibited by activated CD3+ T lymphocytes. According to our findings, the H. pylori vaccine-activated CD3+ has potential immunotherapeutic benefits.


Assuntos
Quitosana , Infecções por Helicobacter , Helicobacter pylori , Nanopartículas , Vacinas de DNA , Humanos , Animais , Camundongos , Helicobacter pylori/genética , Vacinas de DNA/genética , DNA , Vacinação , Infecções por Helicobacter/prevenção & controle , Infecções por Helicobacter/microbiologia , Vacinas Bacterianas/genética , Camundongos Endogâmicos BALB C , Anticorpos Antibacterianos
5.
Int J Nanomedicine ; 19: 3045-3070, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38559447

RESUMO

Background: Diabetes Mellitus is a multisystem chronic pandemic, wound inflammation, and healing are still major issues for diabetic patients who may suffer from ulcers, gangrene, and other wounds from uncontrolled chronic hyperglycemia. Marshmallows or Althaea officinalis (A.O.) contain bioactive compounds such as flavonoids and phenolics that support wound healing via antioxidant, anti-inflammatory, and antibacterial properties. Our study aimed to develop a combination of eco-friendly formulations of green synthesis of ZnO-NPs by Althaea officinalis extract and further incorporate them into 2% chitosan (CS) gel. Method and Results: First, develop eco-friendly green Zinc Oxide Nanoparticles (ZnO-NPs) and incorporate them into a 2% chitosan (CS) gel. In-vitro study performed by UV-visible spectrum analysis showed a sharp peak at 390 nm, and Energy-dispersive X-ray (EDX) spectrometry showed a peak of zinc and oxygen. Besides, Fourier transforms infrared (FTIR) was used to qualitatively validate biosynthesized ZnO-NPs, and transmission electron microscope (TEM) showed spherical nanoparticles with mean sizes of 76 nm and Zeta potential +30mV. The antibacterial potential of A.O.-ZnO-NPs-Cs was examined by the diffusion agar method against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Based on the zone of inhibition and minimal inhibitory indices (MIC). In addition, an in-silico study investigated the binding affinity of A.O. major components to the expected biological targets that may aid wound healing. Althaea Officinalis, A.O-ZnO-NPs group showed reduced downregulation of IL-6, IL-1ß, and TNF-α and increased IL-10 levels compared to the control group signaling pathway expression levels confirming the improved anti-inflammatory effect of the self-assembly method. In-vivo study and histopathological analysis revealed the superiority of the nanoparticles in reducing signs of inflammation and wound incision in rat models. Conclusion: These biocompatible green zinc oxide nanoparticles, by using Althaea Officinalis chitosan gel ensure an excellent new therapeutic approach for quickening diabetic wound healing.


Assuntos
Althaea , Quitosana , Diabetes Mellitus , Nanopartículas Metálicas , Óxido de Zinco , Humanos , Animais , Ratos , Óxido de Zinco/química , Quitosana/química , Althaea/metabolismo , Interleucina-6 , Fator de Necrose Tumoral alfa , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Antibacterianos/química , Cicatrização , Anti-Inflamatórios/farmacologia , Inflamação , Flores , Testes de Sensibilidade Microbiana , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
6.
Sci Rep ; 14(1): 7624, 2024 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561345

RESUMO

It is known that titanium (Ti) implant surfaces exhibit poor antibacterial properties and osteogenesis. In this study, chitosan particles loaded with aspirin, amoxicillin or aspirin + amoxicillin were synthesized and coated onto implant surfaces. In addition to analysing the surface characteristics of the modified Ti surfaces, the effects of the modified Ti surfaces on the adhesion and viability of rat bone marrow-derived stem cells (rBMSCs) were evaluated. The metabolic activities of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) biofilms on the modified Ti surfaces were also measured in vitro. Moreover, S. aureus was tested for its antibacterial effect by coating it in vivo. Using water as the droplet medium, the contact angles of the modified Ti surfaces increased from 44.12 ± 1.75° to 58.37 ± 4.15°. In comparison to those of the other groups tested, significant increases in rBMSC adhesion and proliferation were observed in the presence of aspirin + amoxicillin-loaded microspheres, whereas a significant reduction in the metabolic level of biofilms was observed in the presence of aspirin + amoxicillin-loaded microspheres both in vitro and in vivo. Aspirin and amoxicillin could be used in combination to coat implant surfaces to mitigate bacterial activities and promote osteogenesis.


Assuntos
Amoxicilina , Quitosana , Indóis , Polímeros , Ratos , Animais , Amoxicilina/farmacologia , Aspirina/farmacologia , Titânio/farmacologia , Quitosana/farmacologia , Osteogênese , Staphylococcus aureus , Escherichia coli , Antibacterianos/farmacologia , Propriedades de Superfície , Materiais Revestidos Biocompatíveis/farmacologia
7.
BMC Vet Res ; 20(1): 130, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561827

RESUMO

BACKGROUND: Growing antibiotic resistance has made treating otitis externa (OE) increasingly challenging. On the other hand, local antimicrobial treatments, especially those that combine essential oils (EOs) with nanoparticles, tend to be preferred over systemic ones. It was investigated whether Ajwain (Trachyspermum ammi) EO, combined with chitosan nanoparticles modified by cholesterol, could inhibit the growth of bacterial pathogens isolated from OE cases in dogs. In total, 57 dogs with clinical signs of OE were examined and bacteriologically tested. Hydrogels of Chitosan were synthesized by self-assembly and investigated. EO was extracted (Clevenger machine), and its ingredients were checked (GC-MS analysis) and encapsulated in chitosan-cholesterol nanoparticles. Disc-diffusion and broth Micro-dilution (MIC and MBC) examined its antimicrobial and therapeutic properties. RESULTS: Staphylococcus pseudintermedius (49.3%) was the most common bacteria isolated from OE cases, followed by Pseudomonas aeruginosa (14.7%), Escherichia coli (13.3%), Streptococcus canis (9.3%), Corynebacterium auriscanis (6.7%), Klebsiella pneumoniae (2.7%), Proteus mirabilis (2.7%), and Bacillus cereus (1.3%). The investigation into the antimicrobial properties of Ajwain EO encapsulated in chitosan nanoparticles revealed that it exhibited a more pronounced antimicrobial effect against the pathogens responsible for OE. CONCLUSIONS: Using chitosan nanoparticles encapsulated with EO presents an effective treatment approach for dogs with OE that conventional antimicrobial treatments have not cured. This approach not only enhances antibacterial effects but also reduces the required dosage of antimicrobials, potentially preventing the emergence of antimicrobial resistance.


Assuntos
Ammi , Anti-Infecciosos , Quitosana , Doenças do Cão , Óleos Voláteis , Otite Externa , Cães , Animais , Óleos Voláteis/farmacologia , Quitosana/farmacologia , Otite Externa/tratamento farmacológico , Otite Externa/veterinária , Otite Externa/microbiologia , Testes de Sensibilidade Microbiana/veterinária , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Anti-Infecciosos/uso terapêutico , Bactérias , Escherichia coli , Colesterol , Doenças do Cão/tratamento farmacológico , Doenças do Cão/microbiologia
8.
J Wound Care ; 33(Sup4a): cxi-cxvii, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38588055

RESUMO

OBJECTIVE: Scar tissue formation, as a normal part of wound healing, initiates in the proliferation phase, continues after the remodelling phase, and may cause an unpleasant appearance or disruption in normal functioning. This study investigated the effects of a topical gel on acute wound healing and reducing scars in a rat model. METHOD: ChitoScar (ChitoTech Company, Iran), a commercial scar-reducing gel based on chitosan, was analysed for antibacterial and antiviral activity through a quantitative suspension test. Its cytotoxic effect was investigated, and then irritation and delayed-type hypersensitivity tests were carried out on rabbits through direct application of the gel. Furthermore, the effect of the chitosan-based gel on wound healing and scar tissue formation was studied in rats with an acute wound in two groups: the treatment group (topical application of the chitosan-based gel); and the control group (without treatment). Histopathological examination was carried out based on the inflammatory cells, collagen fibre, keratinocytes and fibroblasts. RESULTS: Analysis revealed that the chitosan-based gel had no cytotoxicity and caused no erythema, oedema, local or other systemic adverse response. Wound healing occurred earlier in the treatment group, which was a result of a significant increase in re-epithelialisation, angiogenesis, fibroblast population and collagen fibre thickness (p<0.05). In the treatment group, wounds healed completely after 21 days and scars totally disappeared after 28 days, while in the control group, wound healing remained incomplete with distinct scar tissue. CONCLUSION: The results demonstrated the positive effect of the chitosan-based gel on the duration and quality of the wound healing process, as well as minimising the scar tissue formation in this in vivo study.


Assuntos
Quitosana , Cicatriz , Ratos , Coelhos , Animais , Quitosana/farmacologia , Quitosana/uso terapêutico , Cicatrização , Pele , Colágeno/farmacologia
9.
Sci Rep ; 14(1): 8247, 2024 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589438

RESUMO

The aim of the present study was to prepare and evaluate Piperine (PP) loaded chitosan lipid nanoparticles (PP-CLNPs) to evaluate its biological activity alone or in combination with the antidiabetic drug Metformin (MET) in the management of cognitive deficit in diabetic rats. Piperine was successfully loaded on CLNPs prepared using chitosan, stearic acid, Tween 80 and Tripolyphosphate (TPP) at different concentrations. The developed CLNPs exhibited high entrapment efficiency that ranged from 85.12 to 97.41%, a particle size in the range of 59.56-414 nm and a negatively charged zeta potential values (- 20.1 to - 43.9 mV). In vitro release study revealed enhanced PP release from CLNPs compared to that from free PP suspensions for up to 24 h. In vivo studies revealed that treatment with the optimized PP-CLNPs formulation (F2) exerted a cognitive enhancing effect and ameliorated the oxidative stress associated with diabetes. PP-CLNPs acted as an effective bio-enhancer which increased the potency of metformin in protecting brain tissue from diabetes-induced neuroinflammation and memory deterioration. These results suggested that CLNPs could be a promising drug delivery system for encapsulating PP and thus can be used as an adjuvant therapy in the management of high-risk diabetic cognitive impairment conditions.


Assuntos
Alcaloides , Benzodioxóis , Quitosana , Disfunção Cognitiva , Diabetes Mellitus Experimental , Lipossomos , Metformina , Nanopartículas , Piperidinas , Alcamidas Poli-Insaturadas , Ratos , Animais , Ratos Wistar , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Disfunção Cognitiva/tratamento farmacológico , Cognição , Metformina/farmacologia , Metformina/uso terapêutico , Tamanho da Partícula , Portadores de Fármacos
10.
Stem Cell Res Ther ; 15(1): 103, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589946

RESUMO

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.


Assuntos
Quitosana , Células-Tronco Mesenquimais , Úlceras Orais , Humanos , Ratos , Animais , Úlceras Orais/terapia , Úlcera , Hidrogéis , Tonsila Palatina , Qualidade de Vida , Modelos Animais , Citocinas
11.
Talanta ; 273: 125857, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38490024

RESUMO

An electrochemical aptasensor was developed for the determination of chloramphenicol (CAP) in fresh foods and food products. The aptasensor was developed using Prussian blue (PB) and chitosan (CS) film. PB acts as a redox probe for detection and CS acts as a sorption material. The aptamer (Apt) was immobilized on a screen-printed carbon electrode (SPCE) modified with gold nanoparticles (AuNPs). Under optimum conditions, the linearity of the aptasensor was between 1.0 and 6.0 × 106 ng L-1 with a detection limit of 0.65 and a quantification limit of 2.15 ng L-1. The electrode could be regenerated up to 24 times without the use of chemicals. The aptasensor showed good repeatability (RSD <11.2%) and good reproducibility (RSD <7.7%). The proposed method successfully quantified CAP in milk, shrimp pond water and shrimp meat with good accuracy (recovery = 88.0 ± 0.6% to 100 ± 2%). The proposed aptasensor could be especially useful in agriculture to ensure the quality of food and the environment and could be used to determine other antibiotics.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Quitosana , Ferrocianetos , Nanopartículas Metálicas , Carbono , Ouro , Limite de Detecção , Cloranfenicol/análise , Reprodutibilidade dos Testes , Eletrodos , Carne , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos
12.
Int J Pharm ; 654: 123999, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38490403

RESUMO

Colorectal cancer (CC) is one of the most predominant malignancies in the world, with the current treatment regimen consisting of surgery, radiation therapy, and chemotherapy. Chemotherapeutic drugs, such as 5-fluorouracil (5-FU), have gained popularity as first-line antineoplastic agents against CC but have several drawbacks, including variable absorption through the gastrointestinal tract, inconsistent liver metabolism, short half-life, toxicological reactions in several organ systems, and others. Therefore, herein, we develop chitosan-coated zinc-substituted cobalt ferrite nanoparticles (CZCFNPs) for the pH-sensitive (triggered by chitosan degradation within acidic organelles of cells) and sustained delivery of 5-FU in CC cells in vitro. Additionally, the developed nanoplatform served as an excellent exogenous optical coherence tomography (OCT) contrast agent, enabling a significant improvement in the OCT image contrast in a CC tissue phantom model with a biomimetic microvasculature. Further, this study opens up new possibilities for using OCT for the non-invasive monitoring and/or optimization of magnetic targeting capabilities, as well as real-time tracking of magnetic nanoparticle-based therapeutic platforms for biomedical applications. Overall, the current study demonstrates the development of a CZCFNP-based theranostic platform capable of serving as a reliable drug delivery system as well as a superior OCT exogenous contrast agent for tissue imaging.


Assuntos
Quitosana , Cobalto , Compostos Férricos , Nanopartículas , Medicina de Precisão , Meios de Contraste , Zinco , Tomografia de Coerência Óptica , Sistemas de Liberação de Medicamentos , Fluoruracila/uso terapêutico , Concentração de Íons de Hidrogênio , Nanomedicina Teranóstica
13.
Biomacromolecules ; 25(4): 2438-2448, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38502912

RESUMO

The treatment of infected wounds faces substantial challenges due to the high incidence and serious infection-related complications. Natural-based hydrogel dressings with favorable antibacterial properties and strong applicability are urgently needed. Herein, we developed a composite hydrogel by constructing multiple networks and loading ciprofloxacin for infected wound healing. The hydrogel was synthesized via a Schiff base reaction between carboxymethyl chitosan and oxidized sodium alginate, followed by the polymerization of the acrylamide monomer. The resultant hydrogel dressing possessed a good self-healing ability, considerable compression strength, and reliable compression fatigue resistance. In vitro assessment showed that the composite hydrogel effectively eliminated bacteria and exhibited an excellent biocompatibility. In a model of Staphylococcus aureus-infected full-thickness wounds, wound healing was significantly accelerated without scars through the composite hydrogel by reducing wound inflammation. Overall, this study opens up a new way for developing multifunctional hydrogel wound dressings to treat wound infections.


Assuntos
Quitosana , Hidrogéis , Hidrogéis/farmacologia , Cicatrização , Antibacterianos/farmacologia , Ciprofloxacina , Bandagens
14.
Biomacromolecules ; 25(4): 2462-2475, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38533630

RESUMO

With wide clinical demands, therapies for traumatic brain injury (TBI) are a major problem in surgical procedures and after major trauma. Due to the difficulty in regeneration of neurons or axons after injury, as well as the inhibition of blood vessel growth by the formation of neural scars, existing treatment measures have limited effectiveness in repairing brain tissue. Herein, the biomultifunctional hydrogels are developed for TBI treatment based on the Schiff base reaction of calcium ion (Ca2+)-cross-linked oxidized sodium alginate (OSA) and carboxymethyl chitosan (CMCS). The obtained COCS hydrogel exhibits excellent adhesion to wet tissues, self-repair capability, and antimicrobial properties. What's particularly interesting is that the addition of Ca2+ increases the hydrogel's extensibility, enhancing its hemostatic capabilities. Biological assessments indicate that the COCS hydrogel demonstrates excellent biocompatibility, hemostatic properties, and the ability to promote arterial vessel repair. Importantly, the COCS hydrogel promotes the growth of cerebral microvessels by upregulating CD31, accelerates the proliferation of astrocytes, enhances the expression of GFAP, and stimulates the expression of neuron-specific markers such as NEUN and ß-tubulin. All of these findings highlight that the strongly adhesive, self-healing, hemostatic hydrogel shows great potential for the repair of traumatic brain injury and other tissue repair therapy.


Assuntos
Lesões Encefálicas Traumáticas , Quitosana , Hemostáticos , Humanos , Hemostáticos/farmacologia , Hidrogéis/farmacologia , Lesões Encefálicas Traumáticas/tratamento farmacológico , Encéfalo , Alginatos/farmacologia , Antibacterianos
15.
J Environ Manage ; 356: 120613, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38547824

RESUMO

The disintegration and instability of aerobic granular sludge (AGS) systems during long-term operation pose significant challenges to its practical implementation, and rapid recovery strategies for disintegrated AGS are gaining more attention. In this study, the recovery and re-stabilization of disintegrated AGS was investigated by adding chitosan to a sequencing batch reactor and simultaneously adjusting the pH to slightly acidic condition. Within 7 days, chitosan addition under slight acidity led to the re-aggregation of disintegrated granules, increasing the average particle size from 166.4 µm to 485.9 µm. Notably, sludge volume indexes at 5 min (SVI5) and 30 min (SVI30) decreased remarkably from 404.6 mL/g and 215.1 mL/g (SVI30/SVI5 = 0.53) to 49.1 mL/g and 47.6 mL/g (SVI30/SVI5 = 0.97), respectively. Subsequent operation for 43 days successfully re-stabilized previous collapsed AGS system, resulting in an average particle size of 750.2 µm. These mature and re-stabilized granules exhibited characteristics of large particle size, excellent settleability, compact structure, and high biomass retention. Furthermore, chitosan facilitated the recovery of COD and nitrogen removal performances within 17-23 days of operation. It effectively facilitated the rapid aggregation of disintegrated granules by charge neutralization and bridging effects under a slightly acidic environment. Moreover, the precipitated chitosan acted as carriers, promoting the adhesion of microorganisms once pH control was discontinued. The results of batch tests and microbial community analysis confirmed that chitosan addition increased sludge retention time, enriching slow-growing microorganisms and enhancing the stability and pollutant removal efficiency of the AGS system.


Assuntos
Quitosana , Esgotos , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Reatores Biológicos , Aerobiose , Nitrogênio/química
16.
Int J Biol Macromol ; 264(Pt 1): 130593, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38437934

RESUMO

Bacterial infection remarkably impedes wound healing, with antibiotics traditionally serving as the primary therapeutic intervention. However, the escalating misuse of antibiotics and the emergence of bacterial resistance present substantial treatment challenges for infected wounds. Consequently, the development of antibiotic-free antimicrobial dressings holds pertinent research and clinical relevance. To this end, this study aimed to introduce an all-natural hydrogel dressing, amalgamating polyphenols and polysaccharides, exhibiting pronounced antibacterial and antioxidant properties without relying on antibiotics. First, we constructed curcumin-tannic acid­zinc ion nanospheres (CTZN) through self-assembly. Our experimental results showed that the nanospheres had excellent biocompatibility, antioxidant, and antimicrobial abilities. Subsequently, we prepared carboxymethylated chitosan/oxidized sodium alginate hydrogels via Schiff base reactions. Incorporation of CTZN into the hydrogel system not only improves the inherent qualities of the hydrogel but also confers multifunctional properties, including antimicrobial, antioxidant, and anti-inflammatory abilities. In this study, we enhanced the physicochemical properties and biological activity of hydrogels by introducing natural material nanospheres, offering a novel approach that could pave the way for the development of purely natural biomaterial dressings.


Assuntos
Quitosana , Curcumina , Nanosferas , Polifenóis , Prunella , Antioxidantes/farmacologia , Polissacarídeos/farmacologia , Antibacterianos/farmacologia , Quitosana/farmacologia , Hidrogéis/farmacologia
17.
J Hazard Mater ; 469: 133922, 2024 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-38442604

RESUMO

The dissemination of antibiotic resistance genes (ARGs), especially via plasmid-mediated horizontal gene transfer, poses a pervasive threat to global health. Chitosan-oligosaccharide (COS) is extensively utilized in medicine, plant and animal husbandry. However, their impact on microflora implies the potential to exert selective pressure on plasmid transfer. To explore the role of COS in facilitating the dissemination of ARGs via plasmid conjugation, we established in vitro mating models. The addition of COS to conjugation mixtures significantly enhanced the transfer of RP4 plasmid and mcr-1 positive IncX4 plasmid in both intra- and inter-specific. Phenotypic and transcriptome analysis revealed that COS enhanced intercellular contact by neutralizing cell surface charge and increasing cell surface hydrophobicity. Additionally, COS increased membrane permeability by inhibiting the Tol-Pal system, thereby facilitating plasmid conjugative transfer. Furthermore, COS served as the carbon source and was metabolized by E. coli, providing energy for plasmid conjugation through regulating the expression of ATPase and global repressor factor-related genes in RP4 plasmid. Overall, these findings improve our awareness of the potential risks associated with the presence of COS and the spread of bacterial antibiotic resistance, emphasizing the need to establish guidelines for the prudent use of COS and its discharge into the environment.


Assuntos
Antibacterianos , Quitosana , Animais , Antibacterianos/farmacologia , Genes Bacterianos , Escherichia coli/genética , Quitosana/farmacologia , Farmacorresistência Bacteriana/genética , Plasmídeos/genética , Transferência Genética Horizontal , Oligossacarídeos/farmacologia
18.
Int J Biol Macromol ; 264(Pt 1): 130602, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38447824

RESUMO

In pursuit of enhancing bone cell proliferation, this study delves into the fabrication of porous scaffolds through the integration of nanomaterials. Specifically, we present the development of highly conductive chitosan (CS) nanonets on fibro-porous polyurethane (PU) bio-membranes. These nanofibers comprise functionalized multiwall carbon nanotubes (fMWCNTs), well-dispersed superparamagnetic iron oxide (SPIONs), and strontium oxide (SrO2) nanoparticles. The resulting porous scaffold exhibits remarkable interfacial biocompatibility, antibacterial properties, and load-bearing capability. Through meticulous in vitro investigations, the CS-PU/SPIONs/SrO2-fMWCNTs nanofibrous scaffolds have demonstrated a propensity to promote bone cell regeneration. Notably, the integration of these nanomaterials has been found to upregulate crucial bone-related markers, including ALP, ARS, COL-I, RUNX2, and SPP-I. The evaluation of these markers, conducted through quantitative real-time polymerase chain reaction (qRT-PCR) and immunocytochemistry, substantiates the improved cell survival and enhanced osteogenic differentiation facilitated by the integrated nanomaterials. This comprehensive analysis underscores the efficacy of CS-PU/SPIONs/SrO2-fMWCNTs bioscaffolds in promoting MC3T3-E1 cell regeneration within, thereby holding promise for advancements in bone tissue engineering and regenerative medicine.


Assuntos
Quitosana , Nanotubos de Carbono , Engenharia Tecidual , Quitosana/farmacologia , Quitosana/química , Osteogênese , Tecidos Suporte/química , Poliuretanos/farmacologia , Regeneração Óssea , Antibacterianos/farmacologia , Proliferação de Células
19.
Int J Biol Macromol ; 264(Pt 1): 130608, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38447840

RESUMO

Bone defects pose significant challenges in orthopedic surgery, often leading to suboptimal outcomes and complications. Addressing these challenges, we employed a three-electrode electrochemical system to fabricate surface-controlled polyaniline nano-tulips (PANINTs) decorated polycaprolactone (PCL) reinforced chitosan functionalized iron oxide nanoparticles (CS-f-Fe2O3) scaffolds. These structures were designed to emulate the natural extracellular matrix (ECM) and promote enhanced osseointegration by establishing a continuous interface between host bone and graft, thereby improving both biological processes and mechanical stability. In vitro experiments demonstrated that PANINTs-PCL/CS-f-Fe2O3 substrates significantly promoted the proliferation, differentiation, and spontaneous outgrowth and extension of MC3T3-E1 cell activity. The nanomaterials exhibited increased cell viability and osteogenic differentiation, as evidenced by elevated expression of bone-related markers such as ALP, ARS, COL-I, RUNX2, and SPP-I, as determined by qRT-PCR. Our findings underscore the regenerative potential of in situ cell culture systems for bone defects, emphasizing the targeted stimulation of essential cell subpopulations to facilitate rapid bone tissue regeneration.


Assuntos
Compostos de Anilina , Quitosana , Quitosana/química , Osteogênese , Tecidos Suporte/química , Regeneração Óssea/fisiologia , Técnicas Eletroquímicas , Engenharia Tecidual/métodos , Diferenciação Celular , Proliferação de Células , Poliésteres/química
20.
Int J Biol Macromol ; 264(Pt 1): 130664, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38453113

RESUMO

In this study, a new chitosan Schiff base with surface modification using citric acid was synthesized for efficient removal of pernicious dyes, namely Bismarck Brown R (BBR) and Rhodamine B (RhB), from wastewater. The physicochemical properties of the modified chitosan Schiff base were comprehensively investigated. Adsorption studies demonstrated that BBR adsorption occurred through monolayer formation, while RhB adsorption proceeded via multilayer formation on the heterogeneous surface. The synthesized adsorbent exhibited exceptional dye removal efficiency, with a Langmuir saturation capacity of 348 ± 11.0 mg.g-1 for BBR and 145 ± 18.44 mg.g-1 for RhB. Isotherm data fitting revealed consistency with the Langmuir isotherm model for BBR and the Freundlich isotherm model for RhB. Notably, the modified chitosan Schiff base showcased enhanced antibacterial properties, effectively inhibiting both gram-positive and gram-negative bacteria. The study's findings underscore the potential of this novel chitosan-based Schiff base as an efficient adsorbent for the removal of various dyes from wastewater, emphasizing its versatility and practical applicability in water treatment processes.


Assuntos
Quitosana , Rodaminas , Poluentes Químicos da Água , Corantes , Águas Residuárias , Antibacterianos/farmacologia , Quitosana/química , Bases de Schiff/química , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Adsorção , Poluentes Químicos da Água/química , Cinética , Concentração de Íons de Hidrogênio
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...