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1.
Biochem Biophys Res Commun ; 654: 47-54, 2023 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-36889034

RESUMO

The bacterial cellulose membrane (CM) is a promising biomaterial due to its easy applicability and moist environment. Moreover, nanoscale silver compounds (AgNO3) are synthesized and incorporated into CMs to provide these biomaterials with antimicrobial activity for wound healing. This study aimed to evaluate the cell viability of CM incorporated with nanoscale silver compounds, determine the minimum inhibitory concentration (MIC) for Escherichia coli and Staphylococcus aureus, and its use on in vivo skin lesions. Wistar rats were divided according to treatment: untreated, CM (cellulose membrane), and AgCM (CM incorporated with silver nanoparticles). The euthanasia was performed on the 2nd, 7th, 14th, and 21st days to assess inflammation (myeloperoxidase-neutrophils, N-acetylglucosaminidase-macrophage, IL-1ß, IL-10), oxidative stress (NO-nitric oxide, DCF-H2O2), oxidative damage (carbonyl: membrane's damage; sulfhydryl: membrane's integrity), antioxidants (superoxide dismutase; glutathione), angiogenesis, tissue formation (collagen, TGF-ß1, smooth muscle α-actin, small decorin, and biglycan proteoglycans). The use of AgCM did not show toxicity, but antibacterial effect in vitro. Moreover, in vivo, AgCM provided balanced oxidative action, modulated the inflammatory profile due to the reduction of IL-1ß level and increase in IL-10 level, in addition to increased angiogenesis and collagen formation. The results suggest the use of silver nanoparticles (AgCM) enhanced the CM properties by providing antibacterial properties, modulation the inflammatory phase, and consequently promotes the healing of skin lesions, which can be used clinically to treat injuries.


Assuntos
Interleucina-10 , Nanopartículas Metálicas , Ratos , Animais , Interleucina-10/farmacologia , Prata/farmacologia , Celulose , Peróxido de Hidrogênio/farmacologia , Ratos Wistar , Cicatrização , Antibacterianos/farmacologia , Bactérias , Colágeno/farmacologia , Modelos Animais
2.
J Microencapsul ; 39(1): 61-71, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34984941

RESUMO

This study aimed to encapsulate and characterise a potential anti-tuberculosis copper complex (CuCl2(INH)2.H2O:I1) into polymeric nanoparticles (PNs) of polymethacrylate copolymers (Eudragit®, Eu) developed by nanoprecipitation method. NE30D, S100 and, E100 polymers were tested. The physicochemical characterisations were performed by DLS, TEM, FTIR, encapsulation efficiency and, in vitro release studies. Encapsulation of I1 in PN-NE30D, PN-E100, and PN-S100 was 26.3%, 94.5%, 22.6%, respectively. The particle size and zeta potentials were 82.3 nm and -24.5 mV for PNs-NE30D, 304.4 nm and +18.7 mV for PNs-E100, and 517.9 nm and -6.9 mV for PNs-S100, respectively. All PDIs were under 0.5. The formulations showed an I1 controlled release at alkaline pH with 29.7% from PNs-NE30D, 7.9% from PNs-E100 and, 28.1% from PNs-S100 at 1 h incubation. PNs were stable for at least 3 months. Particularly, PNs-NE30D demonstrated moderate inhibition of M. tuberculosis and low cytotoxic activity. None of the PNs induced mutagenicity.


Assuntos
Cobre , Nanopartículas , Antibacterianos , Cobre/farmacologia , Mutagênicos , Tamanho da Partícula , Polímeros
3.
Molecules ; 26(1)2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33374301

RESUMO

Bacterial cellulose (BC) is a natural polymer that has fascinating attributes, such as biocompatibility, low cost, and ease of processing, being considered a very interesting biomaterial due to its options for moldability and combination. Thus, BC-based compounds (for example, BC/collagen, BC/gelatin, BC/fibroin, BC/chitosan, etc.) have improved properties and/or functionality, allowing for various biomedical applications, such as artificial blood vessels and microvessels, artificial skin, and wounds dressing among others. Despite the wide applicability in biomedicine and tissue engineering, there is a lack of updated scientific reports on applications related to dentistry, since BC has great potential for this. It has been used mainly in the regeneration of periodontal tissue, surgical dressings, intraoral wounds, and also in the regeneration of pulp tissue. This review describes the properties and advantages of some BC studies focused on dental and oral applications, including the design of implants, scaffolds, and wound-dressing materials, as well as carriers for drug delivery in dentistry. Aligned to the current trends and biotechnology evolutions, BC-based nanocomposites offer a great field to be explored and other novel features can be expected in relation to oral and bone tissue repair in the near future.


Assuntos
Bactérias/química , Materiais Biocompatíveis/química , Celulose/química , Odontologia , Celulose/ultraestrutura , Odontologia/métodos , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/ultraestrutura
4.
J Mater Sci Mater Med ; 29(9): 137, 2018 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-30120580

RESUMO

Fabricating novel materials for biomedical applications mostly require the use of biodegradable materials. In this work biodegradable materials like polylactic acid (PLA) and chitosan (CHS) were used for designing electrospun mats. This work reports the physical and chemical characterization of the PLA-CHS composite, prepared by the electrospinning technique using a mixed solvent system. The addition of chitosan into PLA, offered decrease in fiber diameter in the composites with uniformity in the distribution of fibers with an optimum at 0.4wt% CHS. The fiber formation and the reduction in fiber diameter were confirmed by the SEM micrograph. The inverse gas chromatography and contact angle measurements supported the increase of hydrophobicity of the composite membrane with increase of filler concentration. The weak interaction between PLA and chitosan was confirmed by Fourier transform infrared spectroscopy and thermal analysis. The stability of the composite was established by zeta potential measurements. Cytotoxicity studies of the membranes were also carried out and found that up to 0.6% CHS the composite material was noncytotoxic. The current findings are very important for the design and development of new materials based on polylactic acid-chitosan composites for environmental and biomedical applications.


Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Poliésteres/química , Polímeros/química , Engenharia Tecidual/instrumentação , Algoritmos , Varredura Diferencial de Calorimetria , Sobrevivência Celular , Cromatografia Gasosa , Eletroquímica , Fibroblastos/metabolismo , Humanos , Compostos Inorgânicos/química , Microscopia Eletrônica de Varredura , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Temperatura , Resistência à Tração , Termogravimetria , Fatores de Tempo
5.
J Biol Chem ; 291(45): 23734-23743, 2016 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-27621314

RESUMO

Carbohydrate-binding modules (CBMs) are appended to glycoside hydrolases and can contribute to the degradation of complex recalcitrant substrates such as the plant cell wall. For application in bioethanol production, novel enzymes with high catalytic activity against recalcitrant lignocellulosic material are being explored and developed. In this work, we report the functional and structural study of CBM_E1, which was discovered through a metagenomics approach and is the founding member of a novel CBM family, CBM81. CBM_E1, which is linked to an endoglucanase, displayed affinity for mixed linked ß1,3-ß1,4-glucans, xyloglucan, Avicel, and cellooligosaccharides. The crystal structure of CBM_E1 in complex with cellopentaose displayed a canonical ß-sandwich fold comprising two ß-sheets. The planar ligand binding site, observed in a parallel orientation with the ß-strands, is a typical feature of type A CBMs, although the expected affinity for bacterial crystalline cellulose was not detected. Conversely, the binding to soluble glucans was enthalpically driven, which is typical of type B modules. These unique properties of CBM_E1 are at the interface between type A and type B CBMs.


Assuntos
Bactérias/enzimologia , Celulase/metabolismo , Metagenoma , Saccharum/microbiologia , Microbiologia do Solo , Bactérias/química , Bactérias/genética , Bactérias/metabolismo , Sítios de Ligação , Celulase/química , Celulase/genética , Celulose/metabolismo , Cristalografia por Raios X , Glucanos/metabolismo , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Oligossacarídeos/metabolismo , Conformação Proteica , Termodinâmica , Xilanos/metabolismo
6.
Molecules ; 22(11)2017 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-29165380

RESUMO

Cellulose derivatives have been widely used as adsorbents for the removal of micropollutants such as drugs, dyes, and metals, due to their abundance, low cost and non-contaminating nature. In this context, several studies have been performed searching for new adsorbents (cellulose derivatives) efficient at contaminant removal from aqueous solutions. Thus, a new adsorbent was synthesized by chemical modification of cellulose with ethylenediamine in the absence of solvent and applied to the adsorption of amitriptyline (AMI) in aqueous solution. The modification reaction was confirmed by X-ray Diffraction (XRD), elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry/Differential Scanning Calorimeter (TG/DSC), solid state Nuclear Magnetic Resonance of ¹H and 13C (¹H-NMR and 13C-NMR). Moreover, the effectiveness of reaction was confirmed by computational calculations using Density Functional Theory (DFT) at level B3LYP/6-31G(d). This adsorption process was influenced by pH, time, concentration, temperature and did not show significant changes due to the ionic strength variation. Through these experiments, it was observed that the maximum adsorption capacity of AMI by CN polymer at 298 K, 300 min, and pH 7 was 87.66 ± 0.60 mg·g-1.


Assuntos
Adsorção , Amitriptilina/química , Celulose/química , Etilenodiaminas/química , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , Temperatura , Termodinâmica , Termogravimetria , Difração de Raios X
7.
Drug Dev Ind Pharm ; 42(7): 1066-72, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26596497

RESUMO

In this paper, cellulose triacetate (CTA) was produced from sugarcane bagasse and used as matrices for controlled release of paracetamol. Symmetric and asymmetric membranes were obtained by formulations of CTA/dichloromethane/drug and CTA/dichloromethane/water/drug, respectively, and they were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Different morphologies of membranes were observed by SEM, and the incorporation of paracetamol was confirmed by lowering of the glass transition temperature (Tg) in the DSC curves. This indicates the existence of interactions between the matrix and the drug. The evaluation of drug release was based on the electrochemical monitoring of paracetamol through its oxidation at a glassy carbon electrode surface using square-wave voltammetry (SWV), which provides fast, precise and accurate in situ measurements. The studies showed a content release of 27% and 45% by the symmetric and asymmetric membranes, respectively, during 8 h.


Assuntos
Celulose/análogos & derivados , Portadores de Fármacos/química , Membranas Artificiais , Saccharum/química , Acetaminofen/administração & dosagem , Analgésicos não Narcóticos/administração & dosagem , Varredura Diferencial de Calorimetria , Celulose/química , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Técnicas Eletroquímicas , Propriedades de Superfície , Temperatura
8.
Acta Cir Bras ; 39: e392924, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38958305

RESUMO

PURPOSE: To evaluate using a biocellulose-based hydrogel as an adjuvant in the healing process of arterial ulcers. METHODS: A prospective single group quasi-experimental study was carried out with chronic lower limb arterial ulcer patients. These patients received biocellulose-based hydrogel dressings and outpatient guidance on dressing and periodic reassessments. The primary outcomes were the ulcer-healing rate and product safety, which were assessed by ulcer area measured in photographic records of pre-treatment and posttreatment after 7, 30, and 60 days. Secondary outcomes were related to clinical assessment by the quality-of-life scores (SF-36 and EQ-5D) and pain, evaluated by the visual analogue scale (VAS). RESULTS: Seventeen participants were included, and one of them was excluded. Six patients (37%) had complete wound healing, and all patients had a significant reduction in the ulcer area during follow-up (233.6mm2 versus 2.7mm2) and reduction on the score PUSH 3.0 (p < 0.0001). The analysis of the SF-36 and EQ-5D questionnaires showed a statistically significant improvement in almost all parameters analyzed and with a reduction of pain assessed by the VAS. CONCLUSIONS: The biocellulose-based hydrogel was safe and showed a good perspective to promoting the necessary conditions to facilitate partial or complete healing of chronic arterial ulcers within a 60-day follow-up. Quality of life and pain were positively affected by the treatment.


Assuntos
Qualidade de Vida , Cicatrização , Humanos , Masculino , Feminino , Estudos Prospectivos , Pessoa de Meia-Idade , Idoso , Resultado do Tratamento , Doença Crônica , Celulose/uso terapêutico , Celulose/administração & dosagem , Úlcera da Perna/terapia , Bandagens , Idoso de 80 Anos ou mais , Medição da Dor , Hidrogéis/uso terapêutico
9.
Carbohydr Res ; 539: 109104, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38643706

RESUMO

Cellulose nanocrystals (CNCs) are crystalline domains isolated from cellulosic fibers. They have been utilized in a wide range of applications, such as reinforcing fillers, antibacterial agents and manufacturing of biosensors. Whitin this context, the aim of this work was to obtain and analyze CNCs extracted from bacterial nanocellulose (BNC) using two distinct methods combined with milling pre-treatment: an acidic hydrolysis using 64 % sulfuric acid and an enzymatic hydrolysis using a commercial cellulase enzyme mixture. The CNCs obtained from the enzymatic route (e-CNCs) were observed to be spherical nanoparticles with diameter of 56 ± 11 nm. In contrast, the CNCs from the acid hydrolysis (a-CNCs) appeared as needle-shaped nanoparticles with a high aspect ratio with lengths/widths of 158 ± 64 nm/11 ± 2 nm. The surface zeta potential (ZP) of the a-CNCs was -30,8 mV, whereas the e-CNCs has a potential of +2.70 ± 3.32 mV, indicating that a-CNCs consisted of negatively charged particles with higher stability in solution. Although the acidic route resulted in nanocrystals with a slightly higher crystallinity index compared to the enzymatic route, e-CNCs was found to be more thermally stable than BNC and a-CNCs. Here, we also confirmed the safety of a-CNCs and e-CNCs using L929 cell line. Lastly, this article describes two different CNCs synthesis approaches that leads to the formation of nanoparticles with different dimensions, morphology and unique physicochemical properties. To the best of our knowledge, this is the first study to yield spherical nanoparticles as a result of BNC enzymatic treatment.


Assuntos
Celulose , Nanopartículas , Celulose/química , Nanopartículas/química , Hidrólise , Celulase/química , Celulase/metabolismo , Ácidos Sulfúricos/química , Animais , Camundongos , Tamanho da Partícula
10.
Acta Cir Bras ; 39: e393324, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39016358

RESUMO

PURPOSE: Bacterial cellulose (BC) has shown high capacity for the treatment of wounds and burns, providing a moisty environment. Calcium alginate can be associated with BC to create gels that aid in wound debridement and contribute to appropriate wound healing. This study is aimed at characterizing and evaluating the use of bacterial cellulose/alginate gel in skin burns in rats. METHODS: Cellulose and cellulose/alginate gels were compared regarding the capacity of liquid absorption, moisture, viscosity, and potential cytotoxicity. The 2nd degree burns were produced using an aluminum metal plate (2.0cm) at 120ºC for 20s on the back of rats. The animals were divided into non-treated, CMC(Carboxymethylcellulose), Cellulose(CMC with bacterial cellulose), and Cellulose/alginate(CMC with bacterial cellulose and alginate). The animals received topical treatment 3 times/week. Biochemical (MPO, NAG and oxidative stress), histomorphometry and immunohistochemical assays (IL-1ß IL-10 and VEGF) were conducted on the 14th, 21st, 28th, and 35th days. RESULTS: Cellulose/Alginate gel showed higher absorption capacity and viscosity compared to Cellulose gel, with no cytotoxic effects. Cellulose/alginate presented lower MPO values, a higher percentage of IL-10, with greater and balanced oxidative stress profile. CONCLUSIONS: The use of cellulose/alginate gel reduced neutrophils and macrophage activation and showed greater anti-inflammatory response, which can contribute to healing chronic wounds and burns.


Assuntos
Alginatos , Queimaduras , Celulose , Hidrogéis , Ratos Wistar , Cicatrização , Animais , Alginatos/uso terapêutico , Celulose/uso terapêutico , Queimaduras/tratamento farmacológico , Queimaduras/terapia , Cicatrização/efeitos dos fármacos , Hidrogéis/uso terapêutico , Masculino , Ratos , Ácido Glucurônico/uso terapêutico , Ácidos Hexurônicos/uso terapêutico , Reprodutibilidade dos Testes , Viscosidade , Estresse Oxidativo/efeitos dos fármacos , Imuno-Histoquímica , Fatores de Tempo , Pele/lesões , Pele/efeitos dos fármacos
11.
Int J Biol Macromol ; 228: 1-12, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36543296

RESUMO

This study aimed to develop a multiparticulate system based on sodium alginate/gellan gum polymers for morin controlled release using standardized spray-dryer parameters. A 24 experimental factorial design was used to standardize spray-dryer parameters. After standardization, three systems with three different proportions of the natural polymers (50:50, 25:75, 75:25; sodium alginate: gellan gum) with and without morin (control) were developed. The systems were characterized according to its morphology and physicochemical properties. Next, the systems were evaluated regarding antibiofilm and antimicrobial activity against Streptococcus mutans. The factorial design indicated the use of the following parameters: i) air flow rate: 1.0 m3 /min; ii) outlet temperature: 120 °C; iii) natural polymers combination in different proportions; iiii) polymer concentration: 2 %. Scanning electron microscopy showed microparticles with spherical shape and rough surface. The samples released 99.86 % ± 9.36; 85.45 % ± 8.31; 86.87 % ± 3.83 of morin after 480 min. The systems containing morin significantly reduced S. mutans biofilm biomass, microbial viability and acidogenicity when compared to their respective controls. In conclusion, the spray-dryer parameters were standardized to the highest possible yield values and proved to be efficient for morin encapsulation and controlled release. Furthermore, these systems controlled important virulence factors of S. mutans biofilms.


Assuntos
Biofilmes , Polímeros , Preparações de Ação Retardada , Alginatos/química , Streptococcus mutans
12.
ACS Appl Mater Interfaces ; 15(19): 23146-23159, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37155614

RESUMO

This study explores the use of silica-coated bacterial nanocellulose (BC) scaffolds with bulk macroscopic yet nanometric internal pores/structures as functional supports for high surface area titania aerogel photocatalysts to design flexible, self-standing, porous, and recyclable BC@SiO2-TiO2 hybrid organic-inorganic aerogel membranes for effective in-flow photo-assisted removal of organic pollutants. The hybrid aerogels were prepared by sequential sol-gel deposition of the SiO2 layer over BC, followed by coating of the resulting BC@SiO2 membranes with a porous titania aerogel overlayer of high surface area using epoxide-driven gelation, hydrothermal crystallization, and subsequent supercritical drying. The silica interlayer between the nanocellulose biopolymer scaffold and the titania photocatalyst was found to greatly influence the structure and composition, particularly the TiO2 loading, of the prepared hybrid aerogel membranes, allowing the development of photochemically stable aerogel materials with increased surface area/pore volume and higher photocatalytic activity. The optimized BC@SiO2-TiO2 hybrid aerogel showed up to 12 times faster in-flow photocatalytic removal of methylene blue dye from aqueous solution in comparison with bare BC/TiO2 aerogels and outperformed most of the supported-titania materials reported earlier. Moreover, the developed hybrid aerogels were successfully employed to remove sertraline drug, a model emergent contaminant, from aqueous solution, thus further demonstrating their potential for water purification.


Assuntos
Dióxido de Silício , Titânio , Dióxido de Silício/química , Titânio/química , Biopolímeros/química , Água/química
13.
Acta Trop ; 225: 106192, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34662548

RESUMO

The treatment of cutaneous leishmaniasis (CL) in Brazil using pentavalent antimony (Sbv) is associated with a high failure rate and long time to heal. Moreover, standard Sbv treatment cures only 50-60% of the cases. In this pilot clinical trial, we evaluated the topical use of bacterial cellulose (BC) bio-curatives + Sbv in the treatment of CL caused by L. braziliensis, in Bahia, Brazil. A total of 20 patients were randomized in two groups assigned to receive either parenteral Sbv alone or parenteral Sbv plus topically applied BC bio-curatives. CL patients treated with Sbv + topical BC bio-curatives had a significantly higher cure rate at 60 days post initiation of treatment compared to CL patients treated with Sbv alone (P=0.01). At day 90 post initiation of treatment, cure rate was similar in the two groups as was overall healing time. Adverse effects or local reactions to topical BC application were not observed. This pilot trial shows that the potential use of a combined therapy consisting of topical BC bio-curatives and parenteral Sbv in favoring healing of CL lesions caused by L. braziliensis, at an early time point.


Assuntos
Antiprotozoários , Leishmania braziliensis , Leishmaniose Cutânea , Administração Tópica , Antiprotozoários/uso terapêutico , Celulose/uso terapêutico , Quimioterapia Combinada , Humanos , Leishmaniose Cutânea/tratamento farmacológico
14.
Int J Biol Macromol ; 188: 689-695, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34371050

RESUMO

The incorporation of drugs in nanocomposites can be considered a potential strategy for controlled drug release. In this study, a nanocomposite based on bacterial cellulose and the palygorskite clay (BC/PLG) was produced and loaded with metronidazole (MTZ). The samples were characterized using X-ray diffraction (XRD) Spectroscopy, thermal analysis (TG/DTG) and Scanning Electron Microscopy (SEM). The barrier properties were determined to water vapor permeability (WVP). Adsorption tests with PLG were performed using MTZ and drug release profile of the membranes was investigated. The results indicated that PLG increased the crystallinity of the nanocomposites, and greater thermal stability when PLG concentration was 15.0% (BC/PLG15) was observed. WVP of the samples also varied, according to the clay content. Adsorption equilibrium was achieved from 400 mg/L of the PLG and a plateau in the MTZ release rates from BC/PLG was observed after 30 min. Therefore, the results of this study show the potential of these nanocomposite membranes as a platform for controlled drug release.


Assuntos
Celulose/química , Compostos de Magnésio/química , Metronidazol/farmacologia , Nanocompostos/química , Compostos de Silício/química , Adsorção , Cristalização , Preparações de Ação Retardada/farmacologia , Liberação Controlada de Fármacos , Nanocompostos/ultraestrutura , Permeabilidade , Vapor , Termogravimetria , Difração de Raios X
15.
Int J Biol Macromol ; 162: 1944-1958, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32791274

RESUMO

The use of controlled drug delivery systems represents an alternative and promising strategy for the use of antimicrobials in the oral cavity. Microparticles, films and oral tablets based on alginate and gellan gum were developed also as a strategy to overcome the low aqueous solubility of morin. The systems were characterized in terms of morphological characteristics, mucoadhesion and in vitro drug release. Antibiofilm activity was analyzed for acidogenicity, microbial viability and the composition of the extracellular matrix of single-species biofilms. Scanning Electron Microscopy demonstrated that the microparticles were spherical, rough and compact. The film and the tablet presented smooth and continuous surface and in the inner of the tablet was porous. These systems were more mucoadhesive compared to the microparticles. The in vitro morin release profiles in artificial saliva demonstrated that the microparticles controlled the release better (39.6%), followed by the film (41.1%) and the tablet (91.4%) after 20 h of testing. The morin released from the systems reduced the acidogenicity, microbial viability, concentration of insoluble extracellular polysaccharides and dry weight of biofilms, when compared to the control group. The findings of this study showed that the morin has antibiofilm activity against cariogenic microorganisms.


Assuntos
Alginatos/química , Biofilmes/efeitos dos fármacos , Placa Dentária/tratamento farmacológico , Portadores de Fármacos , Desenho de Fármacos , Flavonoides/farmacologia , Polissacarídeos Bacterianos/química , Actinomyces/efeitos dos fármacos , Administração Oral , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Humanos , Streptococcus mutans/efeitos dos fármacos , Comprimidos/uso terapêutico
16.
ACS Appl Mater Interfaces ; 12(41): 46661-46666, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-32935963

RESUMO

Cellulose is everywhere and renovates in nature continuously and rapidly, while petroleum does not. Unlike the latter, cellulose biodegrades and may represent a carbon sink. Inspired by the multiscale architecture of cellulose, we report on all-cellulose composites comprising cellulose ether as a matrix and highly pure bacterial cellulose nanocrystals (BCNCs) as fillers. Optimum performance as a packaging material was achieved by engineering BCNC surface chemistry as well as the filler-in-matrix dispersion, targeting the replacement of unsustainable, fossil-derived plastics intended for single-use applications. Cost could pose a hurdle, eliminated through the valorization of underutilized scraps from industrial operations, which is also in line with the circular bioeconomy in terms of the integral use of biomass. As far as performance, the optically transparent hydroxypropyl methylcellulose (HPMC) films presented improved tensile strength (from 61 ± 6 to 86 ± 9 MPa) and Young's modulus (from 1.5 ± 0.2 to 2.7 ± 0.4 GPa) while reduced elongation at break (from 15 ± 2 to 12 ± 2%) and water vapor permeability (from 0.40 ± 0.02 to 0.31 ± 0.01 g mm h-1 m-2 kPa-1) when filled with only 5 wt % of (120 ± 31) nm long, (13 ± 3) nm wide, 88% crystalline BCNC. This dual, win-win effect of BCNCs on the mechanical and barrier properties of HPMC films was enabled by a suitable dispersion state, achieved via high-energy mixing, and quenched by casting. This study adds to the current literature on all-cellulose composites and helps pave the route for the technical and economical feasibilities of replacing non-renewable, non-biodegradable plastics in short-term applications by materials that are both renewable and biodegradable, that are also produced through green protocols and isolated from surplus biomass, and that still perform similarly or even better.


Assuntos
Celulose/química , Nanocompostos/química , Nanopartículas/química , Tamanho da Partícula , Estresse Mecânico , Propriedades de Superfície
17.
Int J Biol Macromol ; 147: 1136-1145, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31739047

RESUMO

Biopolymeric blends based on bacterial cellulose (BC) films modified with low molecular weight chitosan (Chi) were developed for controlled release of ciprofloxacin (Cip). Biophysical studies revealed a compatible and cooperative network between BC and Chi including deep structural changes in the BC matrix shown by spectroscopic and thermal analyses (SEM, roughness analysis, FTIR, XRD, TGA, mechanical properties and water vapor transmission rate). Incorporation of chitosan to BC matrix generated a thickening scaffold with high permeability to water vapor from 0.7 to 3.2 g mm/m2 h. Cip loaded onto the BC-Chi film showed a hyperbolic release profile with a 30% decrease in antibiotic release mediated by the presence of Chi. BC-Chi blend films containing Cip tested against Pseudomonas aeruginosa and Staphylococcus aureus showed a synergic effect of chitosan on Cip antimicrobial activity. Besides, in vitro studies revealed the lack of cytotoxicity of BC-Chi-Cip films in human fibroblasts.


Assuntos
Anti-Infecciosos/química , Bandagens , Celulose/química , Quitosana/química , Ciprofloxacina/química , Fibroblastos/efeitos dos fármacos , Anti-Infecciosos/farmacologia , Linhagem Celular , Ciprofloxacina/farmacologia , Fibroblastos/metabolismo , Temperatura Alta , Humanos , Peso Molecular , Permeabilidade , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Termogravimetria
18.
Carbohydr Polym ; 249: 116838, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32933682

RESUMO

Defibrillation of bacterial cellulose by ultra-refining was efficient to release nanofibers (BCNF) which were spray dried with the matrices formers mannitol (MN), maltodextrin or hydroxypropylmethylcellulose. The best microsystem comprised the association of BCNF and MN, so the selected microparticles were loaded with diclofenac sodium or caffeine. Depending on the proportion of BCNF, the nanofibers collapse promoted by spray drying can occur onto surface or into microparticles core, leading to different release behaviors. Samples showed pH-dependent drug release, so the microsystem developed with the lowest BCNF concentration showed important trend to gastroresistance. Caffeine was spray dried as a free drug and for this reason it was devoid of any control over release rates. The set of results showed BCNF can be considered an interesting and potential pharmaceutical excipient for lipophilic drugs. Beyond that, BCNF association with MN can lead to novel enteric drug delivery systems based on natural polymers.


Assuntos
Cafeína/farmacologia , Celulose/química , Diclofenaco/farmacologia , Sistemas de Liberação de Medicamentos , Excipientes/química , Trato Gastrointestinal/efeitos dos fármacos , Nanofibras/química , Animais , Bactérias/metabolismo , Cafeína/química , Diclofenaco/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Fibroblastos/efeitos dos fármacos , Camundongos , Polímeros
19.
Int J Biol Macromol ; 146: 668-677, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31857161

RESUMO

The extensive use of organic molecules (Rhodamine B and Amitriptyline) also has contributed to environmental pollution; adsorption is a relevant method for removal of these contaminants in aqueous media. In this context, the objective of this study was to modify the surface of cellulose (Cel) with phosphoric acid and sodium tripolyphosphate to obtain a biopolymer with incorporated phosphate groups (PCel). The modification was confirmed by X-ray dispersive energy spectroscopy, solid state nuclear magnetic resonance, X-ray diffraction, and thermal analysis. The obtained material (PCel) was used as a Rhodamine B (RhB) or Amitriptyline (AmTP) adsorbent, and the highest adsorption capacity of this material was obtained at pH 3.0 (RhB) and 7.0 (AmTP) and the equilibrium time was achieved at 65 (RhB) and 150 min (AmTP). Moreover, the pseudo-first-order model best describes the kinetics of this adsorption. The experimental adsorption isotherms were adjusted to the Langmuir model, indicating that monolayer adsorption occurred and the highest experimental adsorption capacity obtained was 47.58 (RhB) and 45.52 mg g-1 (AmTP) in PCel. The thermodynamic parameters showed that the adsorption process is exothermic and non-spontaneous, with increase of non-spontaneity with enhance of the temperature. However, PCel was efficient in removing the contaminant (RhB or AmTP) in an aqueous solution.


Assuntos
Amitriptilina/química , Biopolímeros/química , Celulose/química , Rodaminas/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Polifosfatos , Temperatura , Termodinâmica , Água/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Difração de Raios X
20.
J Inorg Biochem ; 212: 111247, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32920435

RESUMO

The aims of this work were to evaluate the antibacterial and antiproliferative potential in vitro of the metal complex with 4-aminobenzoic acid (Ag-pABA) and a drug delivery system based on bacterial cellulose (BC-Ag-pABA). The Ag-pABA complex was characterized by elemental analysis, high resolution mass spectrometry and single-crystal X-ray diffraction techniques, which indicated a 1:2 metal/pABA composition plus a nitrate ion coordinated to silver by the oxygen atom, with the coordination formula [Ag (C7H7NO2)2(NO3)]. The coordination of pABA to the silver ion occurred by the nitrogen atom. The in vitro antibacterial activity of the complex evaluated by minimum inhibitory concentration assays demonstrated the effective growth inhibitory activity against Gram-positive, Gram-negative biofilm producers and acid-alcohol resistant Bacillus. The antiproliferative activities against a panel of eight tumor cells demonstrated the activity of the complex with a significant selectivity index (SI). The DNA interaction capacity and the Ames Test indicated the absence of mutagenicity. The BC-Ag-pABA composite showed an effective capacity of sustained release of Ag-pABA. The observed results validate further studies on its mechanisms of action and the conditions that mediate the in vivo biological effects using animal models to confirm its safety and effectiveness for treatment of skin and soft tissues infected by bacterial pathogens, urinary tract infections and cancer.


Assuntos
Ácido 4-Aminobenzoico/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Celulose/química , Prata/farmacologia , Antibacterianos/química , Preparações de Ação Retardada , Testes de Sensibilidade Microbiana , Prata/química
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