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1.
J Mater Chem B ; 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32647855

RESUMO

As the interest in wearable devices has increased recently, increasing biosensor flexibility has begun to attract considerable attention. Among the various types of biosensors, electrochemical biosensors are uniquely suited for the development of such flexible biosensors due to their many advantages, including their fast response, inherent miniaturization, convenient operation, and portability. Therefore, many studies on flexible electrochemical biosensors have been conducted in recent years to achieve non-invasive and real-time monitoring of body fluids such as tears, sweat, and saliva. To achieve this, various substrates, novel nanomaterials, and detection techniques have been utilized to develop conductive flexible platforms that can be applied to create flexible electrochemical biosensors. In this review, we discussed recently reported flexible electrochemical biosensors and divided them into specific categories including materials for flexible substrate, fabrication techniques for flexible biosensor development, and recently developed flexible electrochemical biosensors to externally monitor target molecules, thereby providing a means to noninvasively examine cells and body fluid samples. In conclusion, this review will discuss the materials, methods, recent studies, and perspectives on flexible electrochemical biosensors for healthcare monitoring and wearable biosensing systems.

2.
Nanoscale ; 12(17): 9306-9326, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32090229

RESUMO

Stem cells show excellent potential in the field of tissue engineering and regenerative medicine based on their excellent capability to not only self-renew but also differentiate into a specialized cell type of interest. However, the lack of a non-destructive monitoring system makes it challenging to identify and characterize differentiated cells before their transplantation without compromising cell viability. Thus, the development of a non-destructive monitoring method for analyzing cell function is highly desired and can significantly benefit stem cell-based therapies. Recently, nanomaterial-based scaffolds (e.g., nanoarrays) have made possible considerable advances in controlling the differentiation of stem cells and characterization of the differentiation status sensitively in real time. This review provides a selective overview of the recent progress in the synthesis methods of nanoarrays and their applications in controlling stem cell fate and monitoring live cell functions electrochemically. We believe that the topics discussed in this review can provide brief and concise guidelines for the development of novel nanoarrays and promote the interest in live cell study applications. A method which can not only control but also monitor stem cell fate and function will be a promising technology that can accelerate stem cell therapies.

3.
Biosens Bioelectron ; 140: 111343, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31150985

RESUMO

The need for flexible biosensors has increased because of their potential applications for point-of-care diagnosis and wearable biosensors. However, flexible biosensors have low sensitivity due to the flexibility of the electrode, and their fabrication involves complex processes. To overcome these limitations, a flexible electrochemical enzyme biosensor was developed in this study by immobilizing an enzyme on the flexible polymer electrode modified with a gold/MoS2/gold nanofilm. The fabrication process involved sputter deposition of gold, spin coating of MoS2, and sputter deposition of gold on the flexible polymer electrode (commercially available Kapton® polyimide film). The flexible glucose biosensor was made by immobilization of glucose oxidase on a flexible electrode by using a chemical linker. The detection limit for glucose was estimated to be 10 nM, which indicates more sensitivity as compared with a previously reported flexible glucose sensor. This sensitivity is due to the facilitation of electron transfer by MoS2. The flexure extension of this biosensor was estimated at 3.48 mm, which is much higher than that of the rigid sensor using a gold-coated silicon electrode (0.09 mm), according to measurements with a micro-fatigue tester. The proposed flexible biosensor composed of the enzyme/gold/MoS2/gold nanofilm on the polymer electrode can be used as a flexible sensing platform for developing wearable biosensing systems because of its high sensitivity, high flexibility, and simple fabrication process.


Assuntos
Aspergillus niger/enzimologia , Técnicas Biossensoriais/instrumentação , Glicemia/análise , Glucose Oxidase/química , Ouro/química , Nanoestruturas/química , Elasticidade , Eletrodos , Enzimas Imobilizadas/química , Desenho de Equipamento , Humanos , Limite de Detecção , Polímeros/química
4.
ACS Appl Mater Interfaces ; 11(9): 8779-8788, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30714374

RESUMO

Nanoparticle-based cell differentiation therapy has attracted increasing research interest as it is a promising substitute for conventional cancer treatment methods. Here, the topological insulator bismuth selenide nanoparticle (Bi2Se3 NP) was core-shelled with silver (Ag@Bi2Se3) to represent remarkable biocompatibility and plasmonic features (ca. 2.3 times higher than those of Ag nanoparticle). Moreover, a newly developed RNA three-way junction (3WJ) structure was designed for the quad-functionalization of any type of nanoparticle and surface. One leg of the 3WJ was attached to the Ag@Bi2Se3, and the other leg harbored a cell-penetrating RNA and a florescence tag. The third leg was designed to inhibit micro-RNA-17 (miR-17) and to further release retinoic acid (RA). A new drug delivery mechanism was developed for the slow release of RA inside the cytosol based on the prerequisite inhibition of miR-17 using a strand displacement strategy. In this paper, we report a simple methodology for resolving the hydrophobicity challenges of RA by its conjugation with a RNA strand (RA/R) through a stimulus-responsive cross-linker. The developed nanobiohybrid material could fully differentiate SH-SY5Y cancer cells into neurons and stop their growth in 6 days without requiring sequential treatments which has not been reported yet. Using a surface-enhanced Raman spectroscopy technique, the RA delivery and the cell differentiation process were monitored nondestructively in real time. The fabricated nanobiohybrid material could open the new horizons in the fabrication of different diagnostic/therapeutic agents.


Assuntos
Nanopartículas Metálicas/química , MicroRNAs/metabolismo , Compostos Organosselênicos/química , Prata/química , Tretinoína/química , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Portadores de Fármacos/química , Endocitose , Humanos , MicroRNAs/antagonistas & inibidores , Microscopia Confocal , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Oligonucleotídeos/química , Povidona/química , Análise Espectral Raman , Tretinoína/metabolismo , Tretinoína/farmacologia
5.
Small ; 14(38): e1802934, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30141567

RESUMO

For the first time, topological insulator bismuth selenide nanoparticles (Bi2 Se3 NP) are core-shelled with gold (Au@Bi2 Se3 ) i) to represent considerably small-sized (11 nm) plasmonic nanoparticles, enabling accurate bioimaging in the near-infrared region; ii) to substantially improve Bi2 Se3 biocompatibility, iii) water dispersibility, and iv) surface functionalization capability through straightforward gold-thiol interaction. The Au@Bi2 Se3 is subsequently functionalized for v) effective targeting of SH-SY5Y cancer cells, vi) disrupting the endosome/lysosome membrane, vii) traceable delivery of antagomiR-152 and further synergetic oncomiR knockdown and photothermal therapy (PTT). Unprecedentedly, it is observed that the Au shell thickness has a significant impact on evoking the exotic plasmonic features of Bi2 Se3 . The Au@Bi2 Se3 possesses a high photothermal conversion efficiency (35.5%) and a remarkable surface plasmonic effect (both properties are approximately twofold higher than those of 50 nm Au nanoparticles). In contrast to the siRNA/miRNA delivery methods, the antagomiR delivery is based on strand displacement, in which the antagomiR-152 is displaced by oncomiR-152 followed by a surface-enhanced Raman spectroscopy signal drop. This enables both cancer cell diagnosis and in vitro real-time monitoring of the antagomiR release. This selective PTT nanoparticle can also efficiently target solid tumors and undergo in vivo PTT, indicating its potential clinical applications.


Assuntos
Antagomirs/química , Ouro/química , Nanopartículas Metálicas/química , Compostos Organosselênicos/química , Fototerapia/métodos , MicroRNAs/genética , RNA Interferente Pequeno/genética , Nanomedicina Teranóstica/métodos
6.
Adv Mater ; 30(39): e1802762, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30073706

RESUMO

Stem cells have attracted increasing research interest in the field of regenerative medicine because of their unique ability to differentiate into multiple cell lineages. However, controlling stem cell differentiation efficiently and improving the current destructive characterization methods for monitoring stem cell differentiation are the critical issues. To this end, multifunctional graphene-gold (Au) hybrid nanoelectrode arrays (NEAs) to: (i) investigate the effects of combinatorial physicochemical cues on stem cell differentiation, (ii) enhance stem cell differentiation efficiency through biophysical cues, and (iii) characterize stem cell differentiation in a nondestructive real-time manner are developed. Through the synergistic effects of physiochemical properties of graphene and biophysical cues from nanoarrays, the graphene-Au hybrid NEAs facilitate highly enhanced cell adhesion and spreading behaviors. In addition, by varying the dimensions of the graphene-Au hybrid NEAs, improved stem cell differentiation efficiency, resulting from the increased focal adhesion signal, is shown. Furthermore, graphene-Au hybrid NEAs are utilized to monitor osteogenic differentiation of stem cells electrochemically in a nondestructive real-time manner. Collectively, it is believed the unique multifunctional graphene-Au hybrid NEAs can significantly advance stem-cell-based biomedical applications.


Assuntos
Diferenciação Celular , Eletrodos , Ouro , Grafite , Osteogênese , Células-Tronco
7.
Int J Mol Sci ; 19(7)2018 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-29997363

RESUMO

Gold nanoparticles (GNPs) have been widely utilized to develop various biosensors for molecular diagnosis, as they can be easily functionalized and exhibit unique optical properties explained by plasmonic effects. These unique optical properties of GNPs allow the expression of an intense color under light that can be tuned by altering their size, shape, composition, and coupling with other plasmonic nanoparticles. Additionally, they can also enhance other optical signals, such as fluorescence and Raman scattering, making them suitable for biosensor development. In this review, we provide a detailed discussion of the currently developed biosensors based on the aforementioned unique optical features of GNPs. Mainly, we focus on four different plasmonic biosensing methods, including localized surface plasmon resonance (LSPR), surface-enhanced Raman spectroscopy (SERS), fluorescence enhancement, and quenching caused by plasmon and colorimetry changes based on the coupling of GNPs. We believe that the topics discussed here are useful and able to provide a guideline in the development of novel GNP-based biosensors in the future.


Assuntos
Técnicas Biossensoriais/métodos , Ouro/química , Nanopartículas Metálicas/química , Calorimetria , Tamanho da Partícula , Análise Espectral Raman , Ressonância de Plasmônio de Superfície
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