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1.
Anal Chem ; 94(24): 8605-8617, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35678711

RESUMO

Neurochemical corelease has received much attention in understanding brain activity and cognition. Despite many attempts, the multiplexed monitoring of coreleased neurochemicals with spatiotemporal precision and minimal crosstalk using existing methods remains challenging. Here, we report a soft neural probe for multiplexed neurochemical monitoring via the electrografting-assisted site-selective functionalization of aptamers on graphene field-effect transistors (G-FETs). The neural probes possess excellent flexibility, ultralight mass (28 mg), and a nearly cellular-scale dimension of 50 µm × 50 µm for each G-FET. As a demonstration, we show that G-FETs with electrochemically grafted molecular linkers (-COOH or -NH2) and specific aptamers can be used to monitor serotonin and dopamine with high sensitivity (limit of detection: 10 pM) and selectivity (dopamine sensor >22-fold over norepinephrine; serotonin sensor >17-fold over dopamine). In addition, we demonstrate the feasibility of the simultaneous monitoring of dopamine and serotonin in a single neural probe with minimal crosstalk and interferences in phosphate-buffered saline, artificial cerebrospinal fluid, and harvested mouse brain tissues. The stability studies show that multiplexed neural probes maintain the capability for simultaneously monitoring dopamine and serotonin with minimal crosstalk after incubating in rat cerebrospinal fluid for 96 h, although a reduced sensor response at high concentrations is observed. Ex vivo studies in harvested mice brains suggest potential applications in monitoring the evoked release of dopamine and serotonin. The developed multiplexed detection methodology can also be adapted for monitoring other neurochemicals, such as metabolites and neuropeptides, by simply replacing the aptamers functionalized on the G-FETs.


Assuntos
Dopamina , Grafite , Animais , Encéfalo/metabolismo , Dopamina/metabolismo , Grafite/química , Camundongos , Norepinefrina , Oligonucleotídeos/metabolismo , Ratos , Serotonina/metabolismo
2.
Angew Chem Int Ed Engl ; : e202203826, 2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35559592

RESUMO

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems have recently received notable attention for their applications in nucleic acid detection. Despite many attempts, the majority of current CRISPR-based biosensors in infectious respiratory disease diagnostic applications still require target preamplifications. This study reports a new biosensor for amplification-free nucleic acid detection via harnessing the trans-cleavage mechanism of Cas13a and ultrasensitive graphene field-effect transistors (gFETs). CRISPR Cas13a-gFET achieves the detection of SARS-CoV-2 and respiratory syncytial virus (RSV) genome down to 1 attomolar without target preamplifications. Additionally, we validate the detection performance using clinical SARS-CoV-2 samples, including those with low viral loads (Ct value >30). Overall, these findings establish our CRISPR Cas13a-gFET among the most sensitive amplification-free nucleic acid diagnostic platforms to date.

3.
Nano Lett ; 22(9): 3668-3677, 2022 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-35439419

RESUMO

The real-time monitoring of neurochemical release in vivo plays a critical role in understanding the biochemical process of the complex nervous system. Current technologies for such applications, including microdialysis and fast-scan cyclic voltammetry, suffer from limited spatiotemporal resolution or poor selectivity. Here, we report a soft implantable aptamer-graphene microtransistor probe for real-time monitoring of neurochemical release. As a demonstration, we show the monitoring of dopamine with nearly cellular-scale spatial resolution, high selectivity (dopamine sensor >19-fold over norepinephrine), and picomolar sensitivity, simultaneously. Systematic benchtop evaluations, ex vivo experiments, and in vivo studies in mice models highlight the key features and demonstrate the capability of capturing the dopamine release dynamics evoked by pharmacological stimulation, suggesting the potential applications in basic neuroscience studies and studying neurological disease-related processes. The developed system can be easily adapted for monitoring other neurochemicals and drugs by simply replacing the aptamers functionalized on the graphene microtransistors.


Assuntos
Dopamina , Grafite , Animais , Camundongos , Norepinefrina , Oligonucleotídeos
4.
Sci Adv ; 8(8): eabn2277, 2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35196090

RESUMO

Extensive studies in both animals and humans have demonstrated that high molecular weight neurochemicals, such as neuropeptides and other polypeptide neurochemicals, play critical roles in various neurological disorders. Despite many attempts, existing methods are constrained by detecting neuropeptide release in small animal models during behavior tasks, which leaves the molecular mechanisms underlying many neurological and psychological disorders unresolved. Here, we report a wireless, programmable push-pull microsystem for membrane-free neurochemical sampling with cellular spatial resolution in freely moving animals. In vitro studies demonstrate the sampling of various neurochemicals with high recovery (>80%). Open-field tests reveal that the device implantation does not affect the natural behavior of mice. The probe successfully captures the pharmacologically evoked release of neuropeptide Y in freely moving mice. This wireless push-pull microsystem creates opportunities for neuroscientists to understand where, when, and how the release of neuropeptides modulates diverse behavioral outputs of the brain.

5.
ACS Appl Mater Interfaces ; 13(28): 33464-33476, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34241991

RESUMO

Encapsulation materials play an important role in many applications including wearable electronics, medical devices, underwater robotics, marine skin tagging system, food packaging, and energy conversation and storage devices. To date, all the encapsulation materials, including polymer layers and inorganic materials, are solid materials. These solid materials suffer from limited barrier lifetimes due to pinholes, cracks, and nanopores or from complicated fabrication processes and limited stretchability for interfacing with complex 3D surfaces. This paper reports a solution to this material challenge by demonstrating bioinspired oil-infused slippery surfaces with excellent waterproof property for the first time. A water vapor transmission test shows that locking a thin layer of oil on the silicone elastomer improves the water vapor barrier performance by three orders of magnitude. Accelerated lifetime tests suggest robust water barrier characteristics that approach 226 days at 37 °C even under severe mechanical damage. A combination of temperature- and thickness-dependent experimental measurements and reaction-diffusion modeling reveals the key waterproof property. In addition to serving as a barrier to water, the oil-infused surface demonstrates an attractive ion barrier property. All these exceptional properties suggest the potential applications of slippery surfaces as encapsulation materials for medical devices, underwater electronics, and many others.


Assuntos
Fluorcarbonetos/química , Óleos/química , Elastômeros de Silicone/química , Interações Hidrofóbicas e Hidrofílicas , Teste de Materiais , Permeabilidade , Óleos de Silicone/química , Vapor , Propriedades de Superfície , Água/química
6.
ACS Sens ; 6(6): 2181-2190, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34038108

RESUMO

Electrolytes play a pivotal role in regulating cardiovascular functions, hydration, and muscle activation. The current standards for monitoring electrolytes involve periodic sampling of blood and measurements using laboratory techniques, which are often uncomfortable/inconvenient to the subjects and add considerable expense to the management of their underlying disease conditions. The wide range of electrolytes in skin interstitial fluids (ISFs) and their correlations with those in plasma create exciting opportunities for applications such as electrolyte and circadian metabolism monitoring. However, it has been challenging to monitor these electrolytes in the skin ISFs. In this study, we report a minimally invasive microneedle-based potentiometric sensing system for multiplexed and continuous monitoring of Na+ and K+ in the skin ISFs. The potentiometric sensing system consists of a miniaturized stainless-steel hollow microneedle to prevent sensor delamination and a set of modified microneedle electrodes for multiplex monitoring. We demonstrate the measurement of Na+ and K+ in artificial ISFs with a fast response time, excellent reversibility and repeatability, adequate selectivity, and negligible potential interferences upon the addition of a physiologically relevant concentration of metabolites, dietary biomarkers, and nutrients. In addition, the sensor maintains the sensitivity after multiple insertions into the chicken skin model. Furthermore, the measurements in artificial ISFs using calibrated sensors confirm the accurate measurements of physiological electrolytes in artificial ISFs. Finally, the skin-mimicking phantom gel and chicken skin model experiments demonstrate the sensor's potential for minimally invasive monitoring of electrolytes in skin ISFs. The developed sensor platform can be adapted for a wide range of other applications, including real-time monitoring of nutrients, metabolites, and proteins.


Assuntos
Técnicas Biossensoriais , Líquido Extracelular , Eletrólitos , Agulhas , Potenciometria
7.
Mikrochim Acta ; 187(7): 390, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32548791

RESUMO

A nanocomposite based on nanofibrillar cellulose (NFC) coated with gold-silver (core-shell) nanoparticles (Au@Ag NPs) was developed as a novel surface-enhanced Raman spectroscopy (SERS) substrate. SERS performance of NFC/Au@Ag NP nanocomposite was tested by 4-mercaptobenzoic acid. The cellulose nanofibril network was a suitable platform that allowed Au@Ag NPs to be evenly distributed and stabilized over the substrate, providing more SERS hotspots for the measurement. Two pesticides, thiram and paraquat, were successfully detected either individually or as a mixture in lettuce by SERS coupled with the nanocomposite. Strong Raman scattering signals for both thiram and paraquat were obtained within a Raman shift range of 400-2000 cm-1 and a Raman intensity ~ 8 times higher than those acquired by NFC/Au NP nanocomposite. Characteristic peaks were clearly observable in all SERS spectra even at a low concentration of 10 µg/L of pesticides. Limit of detection values of 71 and 46 µg/L were obtained for thiram and paraquat, respectively. Satisfactory SERS performance, reproducibility, and sensitivity of NFC/Au@Ag NP nanocomposite validate its applicability for real-world analysis to monitor pesticides and other contaminants in complex food matrices within a short acquisition time. Graphical abstract.


Assuntos
Celulose/química , Alface/química , Nanopartículas Metálicas/química , Nanocompostos/química , Paraquat/análise , Tiram/análise , Ouro/química , Limite de Detecção , Praguicidas/análise , Reprodutibilidade dos Testes , Prata/química , Análise Espectral Raman
8.
Proc Natl Acad Sci U S A ; 116(43): 21427-21437, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31601737

RESUMO

Pharmacology and optogenetics are widely used in neuroscience research to study the central and peripheral nervous systems. While both approaches allow for sophisticated studies of neural circuitry, continued advances are, in part, hampered by technology limitations associated with requirements for physical tethers that connect external equipment to rigid probes inserted into delicate regions of the brain. The results can lead to tissue damage and alterations in behavioral tasks and natural movements, with additional difficulties in use for studies that involve social interactions and/or motions in complex 3-dimensional environments. These disadvantages are particularly pronounced in research that demands combined optogenetic and pharmacological functions in a single experiment. Here, we present a lightweight, wireless, battery-free injectable microsystem that combines soft microfluidic and microscale inorganic light-emitting diode probes for programmable pharmacology and optogenetics, designed to offer the features of drug refillability and adjustable flow rates, together with programmable control over the temporal profiles. The technology has potential for large-scale manufacturing and broad distribution to the neuroscience community, with capabilities in targeting specific neuronal populations in freely moving animals. In addition, the same platform can easily be adapted for a wide range of other types of passive or active electronic functions, including electrical stimulation.


Assuntos
Optogenética/métodos , Farmacologia/métodos , Animais , Encéfalo/metabolismo , Química Encefálica , Channelrhodopsins/metabolismo , Estimulação Elétrica , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Optogenética/instrumentação , Farmacologia/instrumentação , Próteses e Implantes , Tecnologia sem Fio/instrumentação
9.
Lab Chip ; 19(9): 1545-1555, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-30912557

RESUMO

The rich range of biomarkers in sweat and the ability to collect sweat in a non-invasive manner create interest in the use of this biofluid for assessments of health and physiological status, with potential applications that range from sports and fitness to clinical medicine. This paper introduces two important advances in recently reported classes of soft, skin-interfaced microfluidic systems for sweat capture and analysis: (1) a simple, broadly applicable means for collection of sweat that bypasses requirements for physical/mental exertion or pharmacological stimulation and (2) a set of enzymatic chemistries and colorimetric readout approaches for determining the concentrations of creatinine and urea in sweat, throughout ranges that are physiologically relevant. The results allow for routine, non-pharmacological capture of sweat for patient populations, such as infants and the elderly, that cannot be expected to sweat through exercise, and they create potential opportunities in the use of sweat for kidney disease screening/monitoring. Studies on human subjects demonstrate these essential capabilities, with quantitative comparisons to standard methods. The results expand the range of options available in microfluidic sampling and sensing of sweat for disease diagnostics and health monitoring.


Assuntos
Colorimetria/instrumentação , Nefropatias/metabolismo , Dispositivos Lab-On-A-Chip , Suor/metabolismo , Biomarcadores/metabolismo , Humanos
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