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1.
Exp Eye Res ; 244: 109932, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38762008

RESUMO

Drugs that can treat one disease may either be detrimental or beneficial toward another due to possible cross-interactions. Therefore, care in choosing a suitable drug for patients with multiple diseases is crucial in successful patient management. This study explores several currently available ophthalmic drugs used to treat common ocular diseases to understand how they can affect the amyloidogenesis of a transforming growth factor ß-induced protein (TGFBIp) peptide fragment found in abundance in the corneal protein aggregation deposits of lattice corneal dystrophy (LCD) patients. Results from this study provided supporting evidence that some drugs intended to treat other diseases can enhance or inhibit fibrillar aggregation of TGFBIp peptide, which may have potential implication of affecting the disease progression of LCD by either worsening or ameliorating it. Comparisons of the different properties of ophthalmic compounds explored in this study may also provide some guidance for future design of drugs geared toward the treatment of LCD.


Assuntos
Distrofias Hereditárias da Córnea , Proteínas da Matriz Extracelular , Fator de Crescimento Transformador beta , Humanos , Proteínas da Matriz Extracelular/metabolismo , Distrofias Hereditárias da Córnea/metabolismo , Distrofias Hereditárias da Córnea/tratamento farmacológico , Fator de Crescimento Transformador beta/metabolismo , Fragmentos de Peptídeos/farmacologia , Fragmentos de Peptídeos/metabolismo , Soluções Oftálmicas , Amiloide/metabolismo
2.
Proc Natl Acad Sci U S A ; 116(24): 11664-11672, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31123147

RESUMO

Implantable devices for on-demand and pulsatile drug delivery have attracted considerable attention; however, many devices in clinical use are embedded with the electronic units and battery inside, hence making them large and heavy for implantation. Therefore, we propose an implantable device with multiple drug reservoirs capped with a stimulus-responsive membrane (SRM) for on-demand and pulsatile drug delivery. The SRM is made of thermosensitive POSS(MEO2MA-co-OEGMA) and photothermal nanoparticles of reduced graphene oxide (rGO), and each of the drug reservoirs is filled with the same amount of human growth hormone (hGH). Therefore, with noninvasive near-infrared (NIR) irradiation from the outside skin, the rGO nanoparticles generate heat to rupture the SRM in the implanted device, which can open a single selected drug reservoir to release hGH. Therefore, the device herein is shown to release hGH reproducibly only at the times of NIR irradiation without drug leakage during no irradiation. When implanted in rats with growth hormone deficiency and irradiated with an NIR light from the outside skin, the device exhibits profiles of hGH and IGF1 plasma concentrations, as well as body weight change, similar to those in animals treated with conventional s.c. hGH injections.


Assuntos
Hormônio do Crescimento Humano/química , Animais , Sistemas de Liberação de Medicamentos/métodos , Grafite/química , Humanos , Masculino , Nanopartículas/química , Próteses e Implantes , Ratos
3.
Biomacromolecules ; 20(2): 1068-1076, 2019 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-30645935

RESUMO

Most nanoparticle-based bioresearch for clinical applications is unable to overcome the clinical barriers of efficacy (e.g., sensitivity and selectivity), safety for human use, and scalability for mass-production processes. Here, we proposed a promising concept of using a biocompatible nanocarrier that delivers natural fluorescent precursors into cancerous cells. The nanocarrier is a biopolymeric nanoparticle that can be easily loaded with fluorescent precursors to form a fluorescent moiety via a biosynthesis pathway. Once delivered into cancerous cells, the nanocarriers are selectively turned on and distinctively fluoresce upon excitation. We, therefore, demonstrated the efficacy of the selective turn-on fluorescence of the nanocarriers in in vitro coculture models and in vivo tumor-bearing models.


Assuntos
Materiais Biocompatíveis/metabolismo , Portadores de Fármacos/metabolismo , Nanopartículas/metabolismo , Neoplasias/metabolismo , Células 3T3 , Animais , Vias Biossintéticas/efeitos dos fármacos , Linhagem Celular , Fluorescência , Humanos , Camundongos
4.
Int J Mol Sci ; 21(1)2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-31877799

RESUMO

Bone tissue engineering is an alternative therapeutic intervention to repair or regenerate lost bone. This technique requires three essential components: stem cells that can differentiate into bone cells, growth factors that stimulate cell behavior for bone formation, and scaffolds that mimic the extracellular matrix. Among the various kinds of scaffolds, highly porous nanofibrous scaffolds are a potential candidate for supporting cell functions, such as adhesion, delivering growth factors, and forming new tissue. Various fabricating techniques for nanofibrous scaffolds have been investigated, including electrospinning, multi-axial electrospinning, and melt writing electrospinning. Although electrospun fiber fabrication has been possible for a decade, these fibers have gained attention in tissue regeneration owing to the possibility of further modifications of their chemical, biological, and mechanical properties. Recent reports suggest that post-modification after spinning make it possible to modify a nanofiber's chemical and physical characteristics for regenerating specific target tissues. The objectives of this review are to describe the details of recently developed fabrication and post-modification techniques and discuss the advanced applications and impact of the integrated system of nanofiber-based scaffolds in the field of bone tissue engineering. This review highlights the importance of nanofibrous scaffolds for bone tissue engineering.


Assuntos
Regeneração Óssea , Nanofibras/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Animais , Humanos
5.
Sensors (Basel) ; 17(6)2017 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-28587242

RESUMO

Due to the recent demand for high-throughput cellular assays, a lot of efforts have been made on miniaturization of cell-based biosensors by preparing cell microarrays. Various microfabrication technologies have been used to generate cell microarrays, where cells of different phenotypes are immobilized either on a flat substrate (positional array) or on particles (solution or suspension array) to achieve multiplexed and high-throughput cell-based biosensing. After introducing the fabrication methods for preparation of the positional and suspension cell microarrays, this review discusses the applications of the cell microarray including toxicology, drug discovery and detection of toxic agents.


Assuntos
Técnicas Biossensoriais , Descoberta de Drogas , Humanos , Microtecnologia , Miniaturização , Análise Serial de Tecidos
6.
Anal Chem ; 88(12): 6247-53, 2016 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-27214657

RESUMO

Matrix metalloproteinases (MMPs) play a pivotal role in regulating the composition of the extracellular matrix and have a critical role in vascular disease, cancer progression, and bone disorders. This paper describes the design and fabrication of a microdevice as a new platform for highly sensitive MMP-9 detection. In this sensing platform, fluorescein isocyanate (FITC)-labeled MMP-9 specific peptides were covalently immobilized on an electrospun nanofiber matrix to utilize an enzymatic cleavage strategy. Prior to peptide immobilization, the nanofiber matrix was incorporated into hydrogel micropatterns for easy size control and handling of the nanofiber matrix. The resultant hydrogel-framed nanofiber matrix immobilizing the peptides was inserted into microfluidic devices consisting of reaction chambers and detection zones. The immobilized peptides were reacted with the MMP-9-containing solution in a reaction chamber, which resulted in the cleavage of the FITC-containing peptide fragments and subsequently generated fluorescent flow at the detection zone. As higher concentrations of the MMP-9 solution were introduced or larger peptide-immobilizing nanofiber areas were used, more peptides were cleaved, and a stronger fluorescence signal was observed. Due to the huge surface area of the nanofiber and small dimensions of the microsystem, a faster response time (30 min) and lower detection limit (10 pM) could be achieved in this study. The hydrogel-framed nanofiber matrix is disposable and can be replaced with new ones immobilizing either the same or different biomolecules for various bioassays, while the microfluidic system can be continuously reused.


Assuntos
Hidrogéis/química , Metaloproteinase 9 da Matriz/análise , Microfluídica/métodos , Nanofibras/química , Fluoresceína-5-Isotiocianato/química , Proteínas Imobilizadas/química , Proteínas Imobilizadas/metabolismo , Dispositivos Lab-On-A-Chip , Metaloproteinase 9 da Matriz/química , Microscopia de Fluorescência , Peptídeos/química , Peptídeos/metabolismo , Polímeros/química
7.
Analyst ; 140(10): 3375-83, 2015 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-25837891

RESUMO

We developed a novel protein-based bioassay platform utilizing metal-enhanced fluorescence (MEF), which is a hydrogel microarray entrapping silica-coated silver nanoparticles (Ag@SiO2). As a model system, different concentrations of glucose were detected using a fluorescence method by sequential bienzymatic reaction of hydrogel-entrapped glucose oxidase (GOX) and peroxidase (POD) inside a hydrogel microarray. Microarrays based on poly(ethylene glycol)(PEG) hydrogels were prepared by photopatterning a solution containing PEG diacrylate (PEG-DA), photoinitiator, enzymes, and Ag@SiO2. The resulting hydrogel microarrays were able to entrap both enzymes and Ag@SiO2 without leaching and deactivation problems. The presence of Ag@SiO2 within the hydrogel microarray enhanced the fluorescence signal, and the extent of the enhancement was dependent on the thickness of silica shells and the amount of Ag@SiO2. Optimal MEF effects were achieved when the thickness of the silica shell was 17.5 nm, and 0.5 mg mL(-1) of Ag@SiO2 was incorporated into the assay systems. Compared with the standard hydrogel microarray-based assay performed without Ag@SiO2, more than a 4-fold fluorescence enhancement was observed in a glucose concentration range between 10(-3) mM and 10.0 mM using hydrogel microarray entrapping Ag@SiO2, which led to significant improvements in the sensitivity and the limit of detection (LOD). The hydrogel microarray system presented in this study could be successfully combined with a microfluidic device as an initial step to create an MEF-based micro-total-analysis-system (µ-TAS).


Assuntos
Técnicas Biossensoriais/métodos , Glucose Oxidase/metabolismo , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Análise em Microsséries/métodos , Dióxido de Silício/química , Prata/química , Aspergillus niger/enzimologia , Técnicas Biossensoriais/instrumentação , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Glucose/análise , Glucose Oxidase/química , Dispositivos Lab-On-A-Chip , Análise em Microsséries/instrumentação , Polietilenoglicóis/química , Espectrometria de Fluorescência
8.
Angew Chem Int Ed Engl ; 54(39): 11511-5, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26228392

RESUMO

Multi-compartmental non-spherical hydrogel microparticles were fabricated by combining electrospinning and photopatterning. Sequential electrospinning produced multi-layered fiber matrices with different composition in which each layer became a compartment of the particle. Photopatterning of the hydrogel in the presence of the multi-layered fiber matrix generated multi-compartmental microparticles with different vertical functionalities. While the shapes of the hydrogel microparticles were determined by the design of the photomask, the chemical properties and size of each compartment were independently controlled by changing the molecules incorporated into each fiber matrix and the electrospinning times, respectively. The resultant multi-compartmental hydrogel microparticles could carry out not only the release of different growth factors with independent kinetics but also binding of multiple targets at different compartments.


Assuntos
Hidrogéis , Eletroquímica , Microscopia Eletrônica de Varredura , Fotoquímica , Polietilenoglicóis/química
9.
Biomacromolecules ; 15(4): 1382-9, 2014 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-24598017

RESUMO

Self-assembled polymeric nanocapsules (NCs) that incorporate dendrimer porphyrin (DP) in the shells and superparamagnetic iron oxide nanoparticles (SPIONs) in the cores are fabricated to create a theragnostic platform for the application in photodynamic therapy (PDT) and magnetic resonance imaging (MRI). SPIONs-embedded polystyrene NPs (SPIONs@PS) are used as a template to build up multilayered NCs. The formation of PAH/DP multilayer on the SPIONs@PS is monitored by zeta-pential and fluorescence emission measurement, because the porphyrin unit in the core of DP has strong red fluorescence emission. NCs have strong enough magnetic property (>20 emu/g) for MRI application with typical superparamagnetic behavior, where the linear correlation of R2 and Fe concentration at diluted conditions led to corresponding T2 relaxivity coefficient (r2) value of 93.5 mM(-1) s(-1). Cell viability study upon light irradiation reveals that NCs can successfully work in photosensitizer formulation for PDT.


Assuntos
Imageamento por Ressonância Magnética/métodos , Nanocápsulas/química , Nanotecnologia/métodos , Fotoquimioterapia/métodos , Dendrímeros/química , Compostos Férricos/química , Fluorescência , Células HeLa/efeitos dos fármacos , Humanos , Nanocápsulas/uso terapêutico , Nanocápsulas/toxicidade , Fármacos Fotossensibilizantes/química , Poliaminas/química , Poliestirenos/química , Porfirinas/química , Espécies Reativas de Oxigênio/análise
10.
Polymers (Basel) ; 16(2)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38276705

RESUMO

Polyimide (PI) composite films with enhanced mechanical properties were prepared by incorporating modified fumed silica (FS) particles while preserving their optical and thermal characteristics. The PI matrix was synthesized using a fluorinated diamine, a fluorinated dianhydride, and a rigid biphenyl dianhydride via chemical imidization. Commercially available FS particles, including unmodified FS particles (0-FS) and particles modified with dimethyl (2-FS), trimethyl (3-FS), octyl (8-FS), octamethylcyclotetrasiloxane (D4-FS), and polydimethylsiloxane (PDMS-FS) were used. Scanning electron microscope images and nitrogen adsorption-desorption isotherms revealed well-defined porous structures in the FS particles. The water contact angles on the composite films increased compared to those of the pristine PI films, indicating improved water resistance. The PI/0-FS films exhibited a typical trade-off relationship between tensile modulus and elongation at break, as observed in conventional composites. Owing to the poor compatibility and agglomeration of the PDMS-FS particles, the PI/PDMS-FS composite films exhibited poor mechanical performance and diminished optical characteristics. Although the longer-chained FS particles (8- and D4-FS) improved the tensile modulus of the PI film by up to 12%, a reduction of more than 20% in toughness was observed. The PI composite films containing the methylated FS particles (2- and 3-FS) outperformed 8- and D4-FS in terms of mechanical properties, with PI/3-FS films showing an over 10% increased tensile modulus (from 4.07 to 4.42 GPa) and 15% improved toughness (from 6.97 to 8.04 MJ/m3) at 7 wt. % silica loading. Except for the PI/PDMS-FS composites, all composite film samples exhibited more than 86% transmittance at 550 nm. Regarding thermal properties, the glass transition temperature (Tg) and thermal stability remained stable for most composite films. In addition, PI/3-FS films demonstrated enhanced dimensional stability with lower coefficients of thermal expansion (from 47.3 to 34.5 ppm/°C). Overall, this study highlights the potential of incorporating specific modified FS particles to tailor the mechanical, optical, and thermal properties of PI composite films.

11.
Carbohydr Polym ; 338: 122204, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38763712

RESUMO

This study presents the development and characterization of a novel double-network self-healing hydrogel based on N-carboxyethyl chitosan (CEC) and oxidized dextran (OD) with the incorporation of crosslinked collagen (CEC-OD/COL-GP) to enhance its biological and physicochemical properties. The hydrogel formed via dynamic imine bond formation exhibited efficient self-healing within 30 min, and a compressive modulus recovery of 92 % within 2 h. In addition to its self-healing ability, CEC-OD/COL-GP possesses unique physicochemical characteristics including transparency, injectability, and adhesiveness to various substrates and tissues. Cell encapsulation studies confirmed the biocompatibility and suitability of the hydrogel as a cell-culture scaffold, with the presence of a collagen network that enhances cell adhesion, spreading, long-term cell viability, and proliferation. Leveraging their unique properties, we engineered assemblies of self-healing hydrogel modules for controlled spatiotemporal drug delivery and constructed co-culture models that simulate angiogenesis in tumor microenvironments. Overall, the CEC-OD/COL-GP hydrogel is a versatile and promising material for biomedical applications, offering a bottom-up approach for constructing complex structures with self-healing capabilities, controlled drug release, and support for diverse cell types in 3D environments. This hydrogel platform has considerable potential for advancements in tissue engineering and therapeutic interventions.


Assuntos
Adesão Celular , Quitosana , Dextranos , Hidrogéis , Hidrogéis/química , Hidrogéis/farmacologia , Quitosana/química , Dextranos/química , Humanos , Adesão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Colágeno/química , Animais , Liberação Controlada de Fármacos , Proliferação de Células/efeitos dos fármacos , Encapsulamento de Células/métodos , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Camundongos , Biomimética/métodos , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Alicerces Teciduais/química
12.
Bioengineering (Basel) ; 11(1)2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38247931

RESUMO

The corneal endothelium, comprising densely packed corneal endothelial cells (CECs) adhering to Descemet's membrane (DM), plays a critical role in maintaining corneal transparency by regulating water and ion movement. CECs have limited regenerative capacity within the body, and globally, there is a shortage of donor corneas to replace damaged corneal endothelia. The development of a carrier for cultured CECs may address this worldwide clinical need. In this study we successfully manufactured a gelatin nanofiber membrane (gelNF membrane) using electrospinning, followed by crosslinking with glutaraldehyde (GA). The fabricated gelNF membrane exhibited approximately 80% transparency compared with glass and maintained a thickness of 20 µm. The gelNF membrane demonstrated desirable permeability and degradability for a Descemet's membrane analog. Importantly, CECs cultured on the gelNF membrane at high densities showed no cytotoxic effects, and the expression of key CEC functional biomarkers was verified. To assess the potential of this gelNF membrane as a carrier for cultured CEC transplantation, we used it to conduct Descemet's membrane endothelial keratoplasty (DMEK) on rabbit eyes. The outcomes suggest this gelNF membrane holds promise as a suitable carrier for cultured CEC transplantation, offering advantages in terms of transparency, permeability, and sufficient mechanical properties required for successful transplantation.

13.
Int J Biol Macromol ; 270(Pt 1): 132365, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38750850

RESUMO

This study strategically incorporates epidermal growth factor (EGF) and keratinocyte growth factor (KGF) within a hyaluronic acid (HA) hydrogel to enhance corneal wound healing. The controlled release of EGF and KGF from the HA hydrogel is engineered to promote the regeneration of both the epithelial and stromal layers. Specifically, EGF plays a pivotal role in the regeneration of the epithelial layer, while KGF exhibits efficacy in the regeneration of the stromal layer. The combination of these growth factors facilitates efficient regeneration of each layer and demonstrates the capability to modulate each other's regenerative effects. The interplay between EGF and KGF provides an understanding of their cooperative influence on the dynamics of corneal wound healing. The results of this study contribute to the development of advanced strategies for corneal wound management and offer insights into the complex process of corneal regeneration.


Assuntos
Fator de Crescimento Epidérmico , Fator 7 de Crescimento de Fibroblastos , Ácido Hialurônico , Hidrogéis , Cicatrização , Ácido Hialurônico/química , Ácido Hialurônico/farmacologia , Fator de Crescimento Epidérmico/farmacologia , Cicatrização/efeitos dos fármacos , Hidrogéis/química , Hidrogéis/farmacologia , Animais , Humanos , Córnea/efeitos dos fármacos , Córnea/metabolismo , Lesões da Córnea/tratamento farmacológico , Lesões da Córnea/metabolismo , Coelhos
14.
Polymers (Basel) ; 16(6)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38543446

RESUMO

In this study, thiol-functionalized ladder-like polysesquioxanes end-capped with methyl and phenyl groups were synthesized via a simple sol-gel method and characterized through gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). Additionally, epoxy blends of different formulations were prepared. Their structural, flame-retardant, thermal, and mechanical properties, as well as volatile organic compound (VOC) emissions, were determined using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), TGA, scanning electron microscopy (SEM), limiting oxygen index (LOI), cone calorimetry, and a VOC analyzer. Compared to epoxy blends with flame retardants containing elemental phosphorus alone, those with flame retardants containing elemental phosphorus combined with silicon and sulfur exhibited superior thermal, flame-retardant, and mechanical properties with low VOC emissions. SEM of the residual char revealed a dense and continuous morphology without holes or cracks. In particular, LOI values for the combustion of methyl and phenyl end-capped polysilsesquioxane mixtures were 32.3 and 33.7, respectively, compared to 28.4% of the LOI value for the blends containing only phosphorus compounds. The silicon-sulfur-phosphorus-containing blends displayed reduced flammability concerning the blends using a flame retardant containing only phosphorus. This reflects the cooperative effects of various flame-retardant moieties.

15.
J Control Release ; 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38971428

RESUMO

Immunogenic cell death (ICD) holds the potential for in situ tumor vaccination while concurrently eradicating tumors and stimulating adaptive immunity. Most ICD inducers, however, elicit insufficient immune responses due to negative feedback against ICD biomarkers, limited infiltration of antitumoral immune cells, and the immunosuppressive tumor microenvironment (TME). Recent findings highlight the pivotal roles of stimulators of interferon gene (STING) activation, particularly in stimulating antigen-presenting cells (APCs) and TME reprogramming, addressing ICD limitations. Herein, we introduced 'tumor phagocytosis-driven STING activation', which involves the activation of STING in APCs during the recognition of ICD-induced cancer cells. We developed a polypeptide-based nanocarrier encapsulating both doxorubicin (DOX) and diABZI STING agonist 3 (dSA3) to facilitate this hypothesis in vitro and in vivo. After systemic administration, nanoparticles predominantly accumulated in tumor tissue and significantly enhanced anticancer efficacy by activating tumor phagocytosis-driven STING activation in MC38 and TC1 tumor models. Immunological activation of APCs occurred within 12 h, subsequently leading to the activation of T cells within 7 days, observed in both the TME and spleen. Furthermore, surface modification of nanoparticles with cyclic RGD (cRGD) moieties, which actively target integrin αvß3, enhances tumor accumulation and eradication, thereby verifying the establishment of systemic immune memory. Collectively, this study proposes the concept of tumor phagocytosis-driven STING activation and its effectiveness in generating short-term and long-term immune responses.

16.
Nat Commun ; 15(1): 77, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38167486

RESUMO

Research on cultured meat has primarily focused on the mass proliferation or differentiation of muscle cells; thus, the food characteristics of cultured meat remain relatively underexplored. As the quality of meat is determined by its organoleptic properties, cultured meat with similar sensory characteristics to animal-derived meat is highly desirable. In this study, we control the organoleptic and nutritional properties of cultured meat by tailoring the 2D differentiation of primary bovine myoblasts and primary bovine adipose-derived mesenchymal stem cells on gelatin/alginate scaffolds with varying stiffness. We assess the effect of muscle and adipose differentiation quality on the sensory properties of cultured meat. Thereafter, we fabricate cultured meat with similar sensory profiles to that of conventional beef by assembling the muscle and adipose constructs composed of highly differentiated cells. We introduce a strategy to produce cultured meat with enriched food characteristics by regulating cell differentiation with scaffold engineering.


Assuntos
Células-Tronco Mesenquimais , Alicerces Teciduais , Animais , Bovinos , Células Cultivadas , Carne in vitro , Diferenciação Celular
17.
Polymers (Basel) ; 15(14)2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37514415

RESUMO

Polyglycolic acid (PGA) is a promising polymer in the packaging field owing to its excellent hydrolysis, heat resistance, and gas barrier properties, but it is limited in application due to its poor toughness. For this reason, a covalently bonded chain extender is introduced to increase compatibility with flexible polymers. However, covalent bonds are unfavorable for application to degradable plastics because of the energy required for reverse reactions. Therefore, we intended to effectively control the ductility of blending plastics by using a novel ionic chain extender with a relatively weaker non-covalent bond than the existing covalent bond. Polycaprolactone (PCL), which has biodegradability and flexibility, was selected as a blending polymer. For comparison, a covalently reactive chain extender (G-CE) and a non-covalently ionic chain extender (D-CE) were synthesized and compounded with blending plastics. Each chain extender improved the compatibility between PGA and PCL, and the ductility of the PGA/PCL blending plastics was more greatly enhanced with non-covalently bonded D-CE than with covalently bonded G-CE. At this time, the ductility of the PGA/PCL(90/10) blending plastic without CE was 7.2%, the ductility of blending plastic with D-CE (10D) was 26.6%, and the ductility of blending plastic with G-CE (10G) was 18.6%. Therefore, it was confirmed that the novel ionic chain extender inducing non-covalent bonds improves the compatibility between PGA and PCL and is more advantageous in enhancing ductility through a reversible reaction.

18.
Nano Converg ; 10(1): 21, 2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37133613

RESUMO

In this study, we present a promising and facile approach toward the fabrication of non-toxic, water-stable, and eco-friendly luminescent fiber paper composed of polycaprolactone (PCL) polymer and CsPbBr3@SiO2 core-shell perovskite nanocrystals. PCL-perovskite fiber paper was fabricated using a conventional electrospinning process. Transmission electron microscopy (TEM) clearly revealed incorporation of CsPbBr3@SiO2 nanocrystals in the fibers, while scanning electron microscopy (SEM) demonstrated that incorporation of CsPbBr3@SiO2 nanocrystals did not affect the surface and diameter of the PCL-perovskite fibers. In addition, thermogravimetric analysis (TGA) and contact angle measurements have demonstrated that the PCL-perovskite fibers exhibit excellent thermal and water stability. The fabricated PCL-perovskite fiber paper exhibited a bright green emission centered at 520 nm upon excitation by ultra-violet (UV) light (374 nm). We have demonstrated that fluorescent PCL-perovskite fiber paper is a promising candidate for anti-counterfeiting applications because various patterns can be printed on the paper, which only become visible after exposure to UV light at 365 nm. Cell proliferation tests revealed that the PCL-perovskite fibers are cytocompatibility. Consequently, they may be suitable for biocompatible anti-counterfeiting. The present study reveals that PCL-perovskite fibers may pave way toward next generation biomedical probe and anti-counterfeiting applications.

19.
Polymers (Basel) ; 15(13)2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37447592

RESUMO

A novel thiol-functionalized polysilsesqioxane containing hydroxyl and methyl groups was synthesized using a simple acid-catalyzed sol-gel method to develop an epoxy hardener with low odor, low volatile organic compound (VOC) emissions, and fast curing at low temperatures. The synthesized thiol-based hardeners were characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA), and gel permeation chromatography and compared with commercially available hardeners in terms of odor intensity and VOC emissions using the air dilution olfaction method and VOC analysis. The curing behavior and thermal and mechanical properties of the epoxy compounds prepared with the synthesized thiol-based hardeners were also evaluated. The results showed that synthetic thiol-based hardeners containing methyl and hydroxyl groups initiated the curing reaction of epoxy compounds at 53 °C and 45 °C, respectively. In contrast, commercial thiol-based hardeners initiated the curing reaction at 67 °C. Additionally, epoxy compounds with methyl-containing synthetic thiol-based hardeners exhibited higher TGA at a 5% weight loss temperature (>50 °C) and lap shear strength (20%) than those of the epoxy compounds with commercial thiol-based hardeners.

20.
Bioact Mater ; 23: 383-393, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36474658

RESUMO

Bioresponsive hydrogels are smart materials that respond to various external stimuli and exhibit great potential as biosensors owing to their capability of real-time and label-free detection. Here, we propose a sensing platform based on bioresponsive hydrogels, employing the concept of moiré patterns. Two sets of line patterns with different pitch sizes are prepared; a hydrogel grating whose pitch size changes according to external stimuli and a reference grating with constant pitch size. The volume changes of the hydrogel caused by external stimuli changes the pitch size of the hydrogel grating, and subsequently, the pitch sizes of the moiré patterns (moiré signal), whose values can be obtained in a real-time and label-free manner through customized moiré microscopy and signal processing. After confirming that the pH-induced swelling of hydrogel could be monitored using moiré patterns, we performed moiré pattern-based detection of specific proteins using protein-responsive hydrogel that underwent shrinking via interaction with target proteins. Brain-derived neurotrophic factor and platelet-derived growth factor were selected as the model proteins, and our proposed system successfully detected both proteins at nanomolar levels. In both cases, the pitch size change of hydrogel grating was monitored much more sensitively using moiré patterns than through direct measurements. The changes in the moiré signals caused by target proteins were detected in ex-vivo environments using a custom-made intraocular lens incorporating the hydrogel grating, demonstrating the capability of the proposed system to detect various markers in intraocular aqueous humor, when implanted in the eye.

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