Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 237
Filtrar
1.
Small ; : e2401335, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38693088

RESUMO

Exploration of multifunctional integrated catalysts is of great significance for photocatalysis toward practical application. Herein, a 1D confined nanoreactor with a heterogeneous core-shell structure is designed for synergies of efficient catalysis and temperature monitoring by custom encapsulation of Z-scheme heterojunction CuS quantum dots/BiVO4 (CuS QDs/BiVO4) and Y2O2S-Er, Yb. The dispersed active sites created by the QDs with high surface energy improve the mass transfer efficiency, and the efficient electron transport channels at the heterogeneous interface extend the carrier lifetime, which endows the nanoreactor with excellent catalytic performance. Meanwhile, real-time temperature monitoring is realized based on the thermally coupled levels 2H11/2/4S3/2→4I15/2 of Er3+ using fluorescence intensity ratio, which enables the monitorable photocatalysis. Furthermore, the nanoreactor with a multidimensional structure increases effective intermolecular collisions to facilitate the catalytic process by restricting the reaction within distinct enclosed spaces and circumvents potential unknown interaction effects. The design of multi-space nanoconfined reactors opens up a new avenue to modulate catalyst function, providing a unique perspective for photocatalytic applications in the mineralization of organic pollutants, hydrogen production, and nitrogen fixation.

2.
Mol Pharm ; 21(1): 173-182, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37990999

RESUMO

Precisely modulating the synergistic release behavior of multiple bioactive substances has emerged as a formidable challenge in recent years. In this work, we successfully prepared core-sheath nanofibers, where a thin cellulose acetate (CA) coating enrobed the core. Curcumin (Cur) was encapsulated in the core layer as a model drug, while zinc oxide (ZnO) nanoparticles were loaded on the sheath layer. The prepared fiber exhibited a straight cylindrical morphology containing nanoparticles, and the distinct core-sheath nanostructure was demonstrated through transmission electron microscopy (TEM). X-ray diffraction (XRD) and Fourier transform infrared (FTIR) were conducted to study the physical state and compatibility among CA, Cur, and ZnO. Drug release data indicated that core-sheath nanofibers were able to decelerate the rate of drug release, and the thickness of the sheath layer increased in the presence of ZnO particles. Most remarkably, these core-sheath nanofibers exhibited the remarkable ability to sustain the release of drugs and zinc ion (Zn2+), the two-day synergistically release behavior leading to a significant increase in cell proliferation. This material preparation strategy for the synergistic and controlled release of two bioactive substances is instructive for the exploration of innovative and versatile drug delivery systems.


Assuntos
Nanofibras , Óxido de Zinco , Preparações Farmacêuticas , Nanofibras/química , Zinco
3.
Nano Lett ; 23(24): 11809-11817, 2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38048290

RESUMO

Insect sex pheromones as an alternative to chemical pesticides hold promising prospects in pest control. However, their burst release and duration need to be optimized. Herein, pheromone-loaded core-shell fibers composed of degradable polycaprolactone and polyhydroxybutyrate were prepared by coaxial electrospinning. The results showed that this core-shell fiber had good hydrophobic performance and thermal stability, and the light transmittance in the ultraviolet band was only below 40%, which provided protection to pheromones. The core-shell structure alleviated the burst release of pheromone in the fiber and extended the release time to about 133 days. In the field, the pheromone-loaded core-shell fibers showed the same continuous and efficient trapping of Spodoptera litura as the commercial carriers. More importantly, the electrospun fibers combined with biomaterials had a degradability unmatched by commercial carriers. The structure design strategy provides ideas for the innovative design of pheromone carriers and is a potential tool for the management of agricultural pests.


Assuntos
Materiais Biocompatíveis , Feromônios
4.
Sensors (Basel) ; 23(7)2023 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-37050745

RESUMO

This study presents a glucose biosensor based on electrospun core-sheath nanofibers. Two types of film were fabricated using different electrospinning procedures. Film F1 was composed solely of core-sheath nanofibers fabricated using a modified coaxial electrospinning process. Film F2 was a double-layer hybrid film fabricated through a sequential electrospinning and blending process. The bottom layer of F2 comprised core-sheath nanofibers fabricated using a modified process, in which pure polymethacrylate type A (Eudragit L100) was used as the core section and water-soluble lignin (WSL) and phenol were loaded as the sheath section. The top layer of F2 contained glucose oxidase (GOx) and gold nanoparticles, which were distributed throughout the polyvinylpyrrolidone K90 (PVP K90) nanofibers through a single-fluid blending electrospinning process. The study investigated the sequential electrospinning process in detail. The experimental results demonstrated that the F2 hybrid film had a higher degradation efficiency of ß-D-glucose than F1, reaching a maximum of over 70% after 12 h within the concentration range of 10-40 mmol/L. The hybrid film F2 is used for colorimetric sensing of ß-D-glucose in the range of 1-15 mmol/L. The solution exhibited a color that deepened gradually with an increase in ß-D-glucose concentration. Electrospinning is flexible in creating structures for bio-cascade reactions, and the double-layer hybrid film can provide a simple template for developing other sensing nanomaterials.


Assuntos
Nanopartículas Metálicas , Nanofibras , Ouro , Povidona/química , Filmes Cinematográficos , Nanofibras/química
5.
AAPS PharmSciTech ; 24(8): 246, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-38030812

RESUMO

Wound healing is a complex biological process with four main phases: hemostasis, inflammation, proliferation, and remodeling. Current treatments such as cotton and gauze may delay the wound healing process which gives a demand for more innovative treatments. Nanofibers are nanoparticles that resemble the extracellular matrix of the skin and have a large specific surface area, high porosity, good mechanical properties, controllable morphology, and size. Nanofibers are generated by electrospinning method that utilizes high electric force. Electrospinning device composed of high voltage power source, syringe that contains polymer solution, needle, and collector to collect nanofibers. Many polymers can be used in nanofiber that can be from natural or from synthetic origin. As such, electrospun nanofibers are potential scaffolds for wound healing applications. This review discusses the advanced electrospun nanofiber morphologies used in wound healing that is prepared by modified electrospinning techniques.


Assuntos
Nanofibras , Cicatrização , Pele , Polímeros , Bandagens
6.
Int J Mol Sci ; 23(20)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36293527

RESUMO

There is still an urgent need for more efficient biological scaffolds to promote the healing of bone defects. Vessels can accelerate bone growth and regeneration by transporting nutrients, which is an excellent method to jointly increase osteogenesis and angiogenesis in bone regeneration. Therefore, we aimed to prepare a composite scaffold that could promote osteogenesis with angiogenesis to enhance bone defect repair. Here, we report that scaffolds were prepared by coaxial electrospinning with mesoporous bioactive glass modified with amino (MBG-NH2) adsorbing insulin-like growth factor-1 (IGF-1) as the core and silk fibroin (SF) adsorbing vascular endothelial growth factor (VEGF) as the shell. These scaffolds were named MBG-NH2/IGF@SF/VEGF and might be used as repair materials to promote bone defect repair. Interestingly, we found that the MBG-NH2/IGF@SF/VEGF scaffolds had nano-scale morphology and high porosity, as well as enough mechanical strength to support the tissue. Moreover, MBG-NH2 could sustain the release of IGF-1 to achieve long-term repair. Additionally, the MBG-NH2/IGF@SF/VEGF scaffolds could significantly promote the mRNA expression levels of osteogenic marker genes and the protein expression levels of Bmp2 and Runx2 in bone marrow mesenchymal stem cells (BMSCs). Meanwhile, the MBG-NH2/IGF@SF/VEGF scaffolds promoted osteogenesis by simulating Runx2 transcription activity through the phosphorylated Erk1/2-activated pathway. Intriguingly, the MBG-NH2/IGF@SF/VEGF scaffolds could also significantly promote the mRNA expression level of angiogenesis marker genes and the protein expression level of CD31. Furthermore, RNA sequencing verified that the MBG-NH2/IGF@SF/VEGF scaffolds had excellent performance in promoting bone defect repair and angiogenesis. Consistent with these observations, we found that the MBG-NH2/IGF@SF/VEGF scaffolds demonstrated a good repair effect on a critical skull defect in mice in vivo, which not only promoted the formation of blood vessels in the haversian canal but also accelerated the bone repair process. We concluded that these MBG-NH2/IGF@SF/VEGF scaffolds could promote bone defect repair under accelerating angiogenesis. Our finding provides a new potential biomaterial for bone tissue engineering.


Assuntos
Fibroínas , Nanofibras , Camundongos , Animais , Osteogênese , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/farmacologia , Subunidade alfa 1 de Fator de Ligação ao Core , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/farmacologia , Alicerces Teciduais , Fibroínas/farmacologia , Vidro , Regeneração Óssea , Porosidade , Materiais Biocompatíveis/farmacologia , Neovascularização Patológica , RNA Mensageiro
7.
Int J Mol Sci ; 23(18)2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36142896

RESUMO

Bacterial infections and inflammation are two main factors for delayed wound healing. Coaxial electrospinning nanofibrous patches, by co-loading and sequential co-delivering of anti-bacterial and anti-inflammation agents, are promising wound dressing for accelerating wound healing. Herein, curcumin (Cur) was loaded into the polycaprolactone (PCL) core, and broad-spectrum antibacterial tetracycline hydrochloride (TH) was loaded into gelatin (GEL) shell to prepare PCL-Cur/GEL-TH core-shell nanofiber membranes. The fibers showed a clear co-axial structure and good water absorption capacity, hydrophilicity and mechanical properties. In vitro drug release results showed sequential release of Cur and TH, in which the coaxial mat showed good antioxidant activity by DPPH test and excellent antibacterial activity was demonstrated by a disk diffusion method. The coaxial mats showed superior biocompatibility toward human immortalized keratinocytes. This study indicates a coaxial nanofiber membrane combining anti-bacterial and anti-inflammation agents has great potential as a wound dressing for promoting wound repair.


Assuntos
Curcumina , Nanofibras , Antibacterianos/química , Antioxidantes/farmacologia , Curcumina/farmacologia , Gelatina , Humanos , Nanofibras/química , Poliésteres/química , Tetraciclina/farmacologia , Água/química , Cicatrização
8.
Int J Mol Sci ; 23(23)2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36499342

RESUMO

Tissue engineering is nowadays a powerful tool to restore damaged tissues and recover their normal functionality. Advantages over other current methods are well established, although a continuous evolution is still necessary to improve the final performance and the range of applications. Trends are nowadays focused on the development of multifunctional scaffolds with hierarchical structures and the capability to render a sustained delivery of bioactive molecules under an appropriate stimulus. Nanocomposites incorporating hydroxyapatite nanoparticles (HAp NPs) have a predominant role in bone tissue regeneration due to their high capacity to enhance osteoinduction, osteoconduction, and osteointegration, as well as their encapsulation efficiency and protection capability of bioactive agents. Selection of appropriated polymeric matrices is fundamental and consequently great efforts have been invested to increase the range of properties of available materials through copolymerization, blending, or combining structures constituted by different materials. Scaffolds can be obtained from different processes that differ in characteristics, such as texture or porosity. Probably, electrospinning has the greater relevance, since the obtained nanofiber membranes have a great similarity with the extracellular matrix and, in addition, they can easily incorporate functional and bioactive compounds. Coaxial and emulsion electrospinning processes appear ideal to generate complex systems able to incorporate highly different agents. The present review is mainly focused on the recent works performed with Hap-loaded scaffolds having at least one structural layer composed of core/shell nanofibers.


Assuntos
Durapatita , Nanofibras , Durapatita/química , Alicerces Teciduais/química , Engenharia Tecidual/métodos , Regeneração Óssea , Nanofibras/química , Emulsões
9.
Nanomedicine ; 24: 102123, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31711999

RESUMO

Patients with diabetes mellitus have up to a 15% lifetime risk of non-healing and poorly healing wounds. This work develops core-shell nanofibrous bioactive insulin-loaded poly-D-L-lactide-glycolide (PLGA) scaffolds that release insulin in a sustained manner for repairing wounds in diabetic rats. To prepare the biodegradable core-shell nanofibers, PLGA and insulin solutions were fed into two capillary tubes of different sizes that were coaxially electrospun using two independent pumps. The scaffolds sustainably released insulin for four weeks. The hydrophilicity and water-containing capacity of core-shell nanofibrous insulin/PLGA scaffolds significantly exceeded those of blended nanofibrous scaffolds. The nanofibrous core-shell insulin-loaded scaffold reduced the amount of type I collagen in vitro, increased the transforming growth factor-beta content in vivo, and promoted diabetic would repair. The core-shell insulin-loaded nanofibrous scaffolds prolong the release of insulin and promote diabetic wound healing.


Assuntos
Bandagens , Diabetes Mellitus Experimental/tratamento farmacológico , Angiopatias Diabéticas/tratamento farmacológico , Insulina , Nanofibras , Animais , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Angiopatias Diabéticas/metabolismo , Angiopatias Diabéticas/patologia , Insulina/química , Insulina/farmacocinética , Insulina/farmacologia , Nanofibras/química , Nanofibras/uso terapêutico , Ratos , Ratos Sprague-Dawley
10.
AAPS PharmSciTech ; 20(7): 259, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332574

RESUMO

The local delivery of chemotherapy drugs using implantable drug delivery systems is a promising strategy to the treatment of malignant brain tumors. In this study, core/shell chitosan-poly ethylene oxide-carbon quantum dots/carboxymethyl cellulose-polyvinyl alcohol (CS-PEO-CQDs/CMC-PVA) nanofibers were successfully prepared through coaxial electrospinning as a biodegradable polymeric implant for the local delivery of temozolomide (TMZ). Fluorescent carbon dots with carboxyl-rich surface were used as a trackable drug delivery agent for the localized cancer treatment. The effects of several preparation parameters such as voltage, shell to core flow rate, CS/PEO ratio, and PVA/CMC ratio on the structure of nanofibers were investigated. The best nanofibers were obtained in the condition of CS/PEO ratio of 80:20, CMC/PVA ratio of 20:80, shell to core flow rate of 3, and voltage of 25 V. SEM images showed that such nanofibers possess a smooth surface and bead-less structures. The results obtained by DSC indicated that TMZ trapped in the nanofibers existed in an amorphous or disordered crystalline status. In vitro release profile of TMZ from core-shell nanofibers had biphasic patterns. After an initial burst, a continuous drug release was observed for up to 28 days. The in vitro antitumor activity of CQDs-TMZ was tested against the tumor U251 cell lines than the free drug. It has been found that the cytotoxicity of TMZ to U251 cancer cells is enhanced when TMZ is conjugated with CQDs.


Assuntos
Antineoplásicos Alquilantes/administração & dosagem , Nanofibras/química , Pontos Quânticos/química , Temozolomida/administração & dosagem , Antineoplásicos Alquilantes/química , Carboximetilcelulose Sódica/química , Linhagem Celular Tumoral , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Humanos , Polietilenoglicóis/química , Álcool de Polivinil/química , Temozolomida/química
11.
Medicina (Kaunas) ; 55(10)2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31658758

RESUMO

Background and Objectives: A coaxial electrospinning technique was used to produce core/shell nanofibers of a polylactic acid (PLA) as a shell and a polyvinyl alcohol (PVA) containing metformin hydrochloride (MH) as a core. Materials and Methods: Fish sarcoplasmic protein (FSP) was extracted from fresh bonito and incorporated into nanofiber at various concentrations to investigate the influence on properties of the coaxial nanofibers. The morphology, chemical structure and thermal properties of the nanofibers were studied. Results: The results show that uniform and bead-free structured nanofibers with diameters ranging from 621 nm to 681 nm were obtained. A differential scanning calorimetry (DSC) analysis shows that FSP had a reducing effect on the crystallinity of the nanofibers. Furthermore, the drug release profile of electrospun fibers was analyzed using the spectrophotometric method. Conclusions: The nanofibers showed prolonged and sustained release and the first order kinetic seems to be more suitable to describe the release. MTT assay suggests that the produced drug and protein loaded coaxial nanofibers are non-toxic and enhance cell attachment. Thus, these results demonstrate that the produced nanofibers had the potential to be used for diabetic wound healing applications.


Assuntos
Metformina/administração & dosagem , Nanofibras , Animais , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Técnicas In Vitro , Metformina/farmacocinética , Nanofibras/química , Nanofibras/ultraestrutura , Álcool de Polivinil , Retículo Sarcoplasmático , Espectroscopia de Infravermelho com Transformada de Fourier , Atum
12.
Nanomedicine ; 14(5): 1695-1706, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29673978

RESUMO

ZnO and Zn acetate nanoparticles were embedded in polycaprolactone coaxial-fibers and uniaxial-fibers matrices to develop potential antibacterial nanocomposite wound dressings (mats). Morphology, composition, wettability, crystallinity and fiber structure of mats were characterized. Antibacterial properties of mats were tested against E. coli and S. aureus by turbidity and MTT assays. The effect of UVA illumination (prior to bacteria inoculation) on mats' antibacterial activity was also studied. Results showed that a coaxial-fibers design maintained nanoparticles distributed in the outer-shell of fibers and, in general, enhanced the antibacterial effect of the mats, in comparison to conventional uniaxial-fibers mats. Results indicated that mats simultaneously inhibited planktonic and biofilm bacterial growth by, probably, two main antibacterial mechanisms; 1) release of Zn2+ ions (mainly from Zn acetate nanoparticles) and 2) photocatalytic oxidative processes exerted by ZnO nanoparticles. Antibacterial properties of mats were significantly improved by coaxial-fibers design and exposure to UVA-light prior to bacteria inoculation.


Assuntos
Antibacterianos/administração & dosagem , Escherichia coli/efeitos dos fármacos , Nanofibras/administração & dosagem , Poliésteres/química , Staphylococcus aureus/efeitos dos fármacos , Acetato de Zinco/administração & dosagem , Óxido de Zinco/administração & dosagem , Antibacterianos/química , Bandagens , Escherichia coli/crescimento & desenvolvimento , Nanofibras/química , Nanotecnologia , Staphylococcus aureus/crescimento & desenvolvimento , Acetato de Zinco/química , Óxido de Zinco/química
13.
Nano Lett ; 17(12): 7989-7994, 2017 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-29166026

RESUMO

Rational design of optimal bifunctional oxygen electrocatalyst with low cost and high activity is greatly desired for realization of rechargeable Zn-air batteries. Herein, we fabricate mesoporous thin-walled CuCo2O4@C with abundant nitrogen-doped nanotubes via coaxial electrospinning technique. Benefiting from high catalytic activity of ultrasmall CuCo2O4 particles, double active specific surface area of mesoporous nanotubes, and strong coupling with N-doped carbon matrix, the obtained CuCo2O4@C exhibits outstanding oxygen electrocatalytic activity and stability, in terms of a positive onset potential (0.951 V) for oxygen reduction reaction (ORR) and a low overpotential (327 mV at 10 mA cm-2) for oxygen evolution reaction (OER). Significantly, when used as cathode catalyst for Zn-air batteries, CuCo2O4@C also displays a low charge-discharge voltage gap (0.79 V at 10 mA cm-2) and a long cycling life (up to 160 cycles for 80 h). With desirable architecture and excellent electrocatalytic properties, the CuCo2O4@C is considered a promising electrocatalyst for Zn-air batteries.

14.
Mol Pharm ; 13(12): 4129-4140, 2016 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-27700124

RESUMO

It is hypothesized that thiolated chitosan (TCS) core/shell nanofibers (NFs) can enhance the drug loading of tenofovir, a model low molecular weight and highly water-soluble drug molecule, and improve its mucoadhesivity and in vivo safety. To test this hypothesis, poly(ethylene oxide) (PEO) core with TCS and polylactic acid (PLA) shell NFs are fabricated by a coaxial electrospinning technique. The morphology, drug loading, drug release profiles, cytotoxicity and mucoadhesion of the NFs are analyzed using scanning and transmission electron microscopies, liquid chromatography, cytotoxicity assays on VK2/E6E7 and End1/E6E7 cell lines and Lactobacilli crispatus, fluorescence imaging and periodic acid colorimetric method, respectively. In vivo safety studies are performed in C57BL/6 mice followed by H&E and immunohistochemical (CD45) staining analysis of genital tract. The mean diameters of PEO, PEO/TCS, and PEO/TCS-PLA NFs are 118.56, 9.95, and 99.53 nm, respectively. The NFs exhibit smooth surface. The drug loading (13%-25%, w/w) increased by 10-fold compared to a nanoparticle formulation due to the application of the electrospinning technique. The NFs are noncytotoxic at the concentration of 1 mg/mL. The PEO/TCS-PLA core/shell NFs mostly exhibit a release kinetic following Weibull model (r2 = 0.9914), indicating the drug release from a matrix system. The core/shell NFs are 40-60-fold more bioadhesive than the pure PEO based NFs. The NFs are nontoxic and noninflammatory in vivo after daily treatment for up to 7 days. Owing to their enhanced drug loading and preliminary safety profile, the TCS core/shell NFs are promising candidates for the topical delivery of HIV/AIDS microbicides such as tenofovir.


Assuntos
Quitosana/química , Inflamação/tratamento farmacológico , Nanofibras/química , Nanopartículas/química , Inibidores da Transcriptase Reversa/farmacologia , Compostos de Sulfidrila/química , Tenofovir/farmacologia , Animais , Células Cultivadas , Quitosana/administração & dosagem , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Feminino , Humanos , Inflamação/patologia , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Nanofibras/administração & dosagem , Nanopartículas/administração & dosagem , Inibidores da Transcriptase Reversa/química , Tenofovir/química
15.
Mol Pharm ; 13(7): 2457-65, 2016 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-27280491

RESUMO

New methods for creating theranostic systems with simultaneous encapsulation of therapeutic, diagnostic, and targeting agents are much sought after. This work reports for the first time the use of coaxial electrospinning to prepare such systems in the form of core-shell fibers. Eudragit S100 was used to form the shell of the fibers, while the core comprised poly(ethylene oxide) loaded with the magnetic resonance contrast agent Gd(DTPA) (Gd(III) diethylenetriaminepentaacetate hydrate) and indomethacin as a model therapeutic agent. The fibers had linear cylindrical morphologies with clear core-shell structures, as demonstrated by electron microscopy. X-ray diffraction and differential scanning calorimetry proved that both indomethacin and Gd(DTPA) were present in the fibers in the amorphous physical form. This is thought to be a result of intermolecular interactions between the different components, the presence of which was suggested by infrared spectroscopy. In vitro dissolution tests indicated that the fibers could provide targeted release of the active ingredients through a combined mechanism of erosion and diffusion. The proton relaxivities for Gd(DTPA) released from the fibers into tris buffer increased (r1 = 4.79-9.75 s(-1) mM(-1); r2 = 7.98-14.22 s(-1) mM(-1)) compared with fresh Gd(DTPA) (r1 = 4.13 s(-1) mM(-1) and r2 = 4.40 s(-1) mM(-1)), which proved that electrospinning has not diminished the contrast properties of the complex. The new systems reported herein thus offer a new platform for delivering therapeutic and imaging agents simultaneously to the colon.


Assuntos
Meios de Contraste/química , Diagnóstico por Imagem/métodos , Sistemas de Liberação de Medicamentos/métodos , Nanomedicina Teranóstica/métodos , Varredura Diferencial de Calorimetria , Meios de Contraste/síntese química , Portadores de Fármacos/química , Gadolínio DTPA/química , Lantânio/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
16.
Mol Pharm ; 13(3): 729-36, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26870885

RESUMO

Core-shell fibers are emerging as interesting microstructures for the controlled release of drugs, proteins, and complex biological molecules, enabling the fine control of microreservoirs of encapsulated active agents, of the release kinetics, and of the localized delivery. Here we load luminescent molecules and enhanced green fluorescent proteins into the core of fibers realized by coaxial electrospinning. Photoluminescence spectroscopy evidences unaltered molecular emission following encapsulation and release. Moreover, the release kinetics is microscopically investigated by confocal analysis at individual-fiber scale, unveiling different characteristic time scales for diffusional translocation at the core and at the shell. These results are interpreted by a two stage desorption model for the coaxial microstructure, and they are relevant in the design and development of efficient fibrous systems for the delivery of functional biomolecules.


Assuntos
Técnicas Eletroquímicas/métodos , Proteínas de Fluorescência Verde/metabolismo , Nanofibras/química , Polímeros/química , Difusão , Humanos , Solubilidade
17.
Mol Pharm ; 13(4): 1393-404, 2016 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-26950163

RESUMO

Sustained controlled drug release is one of the prominent contributions for more successful treatment outcomes in the case of several diseases. However, the incorporation of hydrophilic drugs into nanofibers, a promising novel delivery system, and achieving a long-term sustained release still pose a challenging task. In this work we demonstrated a robust method of avoiding burst release of drugs and achieving a sustained drug release from 2 to 4 weeks using core-shell nanofibers with poly(methyl methacrylate) (PMMA) shell and monolithic poly(vinyl alcohol) (PVA) core or a novel type of core-shell nanofibers with blended (PVA and PMMA) core loaded with ciprofloxacin hydrochloride (CIP). It is also shown that, for core-shell nanofibers with monolithic core, drug release can be manipulated by varying flow rate of the core PVA solution, whereas for core-shell nanofibers with blended core, drug release can be manipulated by varying the ratios between PMMA and PVA in the core. During coaxial electrospinning, when the solvent from the core evaporates in concert with the solvent from the shell, the interconnected pores spanning the core and the shell are formed. The release process is found to be desorption-limited and agrees with the two-stage desorption model. Ciprofloxacin-loaded nanofiber mats developed in the present work could be potentially used as local drug delivery systems for treatment of several medical conditions, including periodontal disease and skin, bone, and joint infections.


Assuntos
Ciprofloxacina/química , Sistemas de Liberação de Medicamentos/métodos , Nanofibras/química , Preparações de Ação Retardada , Interações Hidrofóbicas e Hidrofílicas , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Magn Reson Med ; 73(1): 299-305, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24469863

RESUMO

PURPOSE: A range of advanced diffusion MRI (dMRI) techniques are currently in development which characterize the orientation of white matter fibers using diffusion tensor imaging (DTI). There is a need for a physical phantom with microstructural features of the brain's white matter to help validate these methods. METHODS: Hollow, co-electrospun, aligned fibers with a tuneable size distribution have been produced in bulk and with an MR visible solvent infused into the pores. The morphology and size of the phantoms was assessed using scanning electron microscopy (SEM) and compared with DTI results obtained on both a clinical and preclinical scanner. RESULTS: By varying inner diameter of the phantom fibers (from SEM: 9.5 µm, 11.9 µm, 13.4 µm) the radial diffusivity and fractional anisotropy, calculated from DTI, vary between 0.38 ± 0.05 × 10(3) and 0.61 ± 0.06 × 10(3) cm s(-1) and between 0.45 ± 0.05 and 0.33 ± 0.04, respectively. CONCLUSION: We envisage that these materials will be used for the validation of novel and established methods within the field of diffusion MRI, as well as for routine quality assurance purposes and for establishing scanner performance in multicenter trials.


Assuntos
Materiais Biomiméticos , Encéfalo/anatomia & histologia , Imagem de Tensor de Difusão/instrumentação , Interpretação de Imagem Assistida por Computador/instrumentação , Imagens de Fantasmas , Substância Branca/anatomia & histologia , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Biopolymers ; 101(4): 336-46, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23913748

RESUMO

Coaxial electrospinning is used to fabricate nanofibers with gelatin in the shell and polyvinyl alcohol (PVA) in the core in order to derive mechanical strength from PVA and bioactivity from gelatin. At a 1:1 PVA/gelatin mass ratio, the core-shell nanofiber scaffolds display a Young's modulus of 168.6 ± 36.5 MPa and a tensile strength of 5.42 ± 1.95 MPa, which are significantly higher than those of the scaffolds composed solely of gelatin or PVA. The Young's modulus and tensile strength of the core-shell nanofibers are further improved by reducing the PVA/gelatin mass ratio from 1:1 to 1:3. The mechanical analysis of the core-shell nanofibers suggests that the presence of the gelatin shell may improve the molecular alignment of the PVA core, transforming the semi-crystalline, plastic PVA into a more crystallized, elastic PVA, and enhancing the mechanical properties of the core. Lastly, the PVA/gelatin core-shell nanofibers possess cellular viability, proliferation, and adhesion similar to these of the gelatin nanofibers, and show significantly higher proliferation and adhesion than the PVA nanofibers. Taken together, the coaxial electrospinning of nanofibers with a core-shell structure permits integration of the bioactivity of gelatin and the mechanical strength of PVA in single fibers.


Assuntos
Gelatina/farmacologia , Fenômenos Mecânicos , Nanofibras/química , Álcool de Polivinil/farmacologia , Animais , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Nanofibras/ultraestrutura , Tamanho da Partícula , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Alicerces Teciduais/química
20.
Connect Tissue Res ; 55(4): 292-8, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24844413

RESUMO

Poly(lactic-co-glycolic acid) (PLGA)/collagen nanofibrous scaffolds have been utilized in the tissue engineering field. It has been shown that both fibronectin (FN) and cadherin 11 (CDH) play important roles in the progress of osteogenesis and cell adhesion. The aim of this study was to fabricate recombinant FN/CDHs (rFN/CDHs)-loaded PLGA/collagen nanofibrous scaffolds and evaluate their effects on the adhesion and differentiation of human bone marrow mesenchymal stem cells (hMSCs). PLGA/collagen nanofibers were made by coaxial electrospinning. The morphology and mechanical properties of PLGA/collagen nanofibrous mats were analyzed by scanning electron microscopy and mechanical testing, respectively. The performance of scaffolds was evaluated in terms of the viability, morphology, and osteogenic gene expression levels of hMSCs. rFN/CDHs was successfully incorporated into the PLGA/collagen nanofibers. The release of rFN/CDHs from PLGA nanofibers was investigated by liquid chromatography-mass spectrometry. rFN/CDHs improved the mechanical properties of the PLGA/collagen nanofibers. The controlled release of rFN/CDHs can enhance the proliferation of hMSCs and induce osteogenic gene expression (alkaline phosphatase, RUNX2, and osteocalcin). Our data imply that rFN/CDHs may induce hMSCs differentiation into osteoblasts and PLGA/collagen nanofibers loaded with rFN/CDHs have potential in bone tissue engineering.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Substitutos Ósseos/química , Caderinas/química , Colágeno/química , Fibronectinas/química , Células-Tronco Mesenquimais/metabolismo , Nanofibras/química , Osteogênese , Alicerces Teciduais/química , Caderinas/genética , Células Cultivadas , Fibronectinas/genética , Humanos , Células-Tronco Mesenquimais/citologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Engenharia Tecidual/métodos
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa