scholarly journals Electro-plasmonic nanoantenna: A nonfluorescent optical probe for ultrasensitive label-free detection of electrophysiological signals

2019 ◽  
Vol 5 (10) ◽  
pp. eaav9786 ◽  
Author(s):  
Ahsan Habib ◽  
Xiangchao Zhu ◽  
Uryan I. Can ◽  
Maverick L. McLanahan ◽  
Pinar Zorlutuna ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Measurements ◽  
Optical Probe ◽  
Optical Recording ◽  
High Temporal Resolution ◽  
Label Free ◽  
Spatiotemporal Resolution ◽  
Photon Count ◽  
Label Free Detection ◽  
Electrophysiological Signals

Harnessing the unprecedented spatiotemporal resolution capability of light to detect electrophysiological signals has been the goal of scientists for nearly 50 years. Yet, progress toward that goal remains elusive due to lack of electro-optic translators that can efficiently convert electrical activity to high photon count optical signals. Here, we introduce an ultrasensitive and extremely bright nanoscale electric-field probe overcoming the low photon count limitations of existing optical field reporters. Our electro-plasmonic nanoantennas with drastically enhanced cross sections (~104 nm2 compared to typical values of ~10−2 nm2 for voltage-sensitive fluorescence dyes and ~1 nm2 for quantum dots) offer reliable detection of local electric-field dynamics with remarkably high sensitivities and signal–to–shot noise ratios (~60 to 220) from diffraction-limited spots. In our electro-optics experiments, we demonstrate high-temporal resolution electric-field measurements at kilohertz frequencies and achieved label-free optical recording of network-level electrogenic activity of cardiomyocyte cells with low-intensity light (11 mW/mm2).

scholarly journals Label-free detection of ATP release from living astrocytes with high temporal resolution using carbon nanotube network

2009 ◽  
Vol 24 (8) ◽  
pp. 2716-2720 ◽  
Author(s):  
Yinxi Huang ◽  
Herry Gunadi Sudibya ◽  
Dongliang Fu ◽  
Renhao Xue ◽  
Xiaochen Dong ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Temporal Resolution ◽  
Atp Release ◽  
High Temporal Resolution ◽  
Label Free ◽  
Label Free Detection ◽  
Carbon Nanotube Network

scholarly journals Label-free optical detection of bioelectric potentials using electrochromic thin films

2020 ◽  
Author(s):  
Felix S. Alfonso ◽  
Yuecheng Zhou ◽  
Erica Liu ◽  
Allister F. McGuire ◽  
Yang Yang ◽  
...  
Keyword(s):  
Thin Films ◽  
Brain Slices ◽  
Optical Probe ◽  
Optical Recording ◽  
Dorsal Root Ganglion Neurons ◽  
Frame Rate ◽  
Label Free ◽  
Spontaneous Action ◽  
Ganglion Neurons ◽  
Spontaneous Action Potentials

AbstractUnderstanding how a network of interconnected neurons receives, stores, and processes information in the human brain is one of the outstanding scientific challenges of our time. The ability to reliably detect neuroelectric activities is essential to addressing this challenge. Optical recording using voltage-sensitive fluorescent probes has provided unprecedented flexibility for choosing regions of interest in recording neuronal activities. However, when recording at a high frame rate such as 500-1000 Hz, fluorescence-based voltage sensors often suffer from photobleaching and phototoxicity, which limit the recording duration. Here, we report a new approach, Electro-Chromic Optical REcording (ECORE), that achieves label-free optical recording of spontaneous neuroelectrical activities. ECORE utilizes the electrochromism of PEDOT:PSS thin films, whose optical absorption can be modulated by an applied voltage. Being based on optical reflection instead of fluorescence, ECORE offers the flexibility of an optical probe without suffering from photobleaching or phototoxicity. Using ECORE, we optically recorded spontaneous action potentials in cardiomyocytes, cultured hippocampal and dorsal root ganglion neurons, and brain slices. With minimal perturbation to cells, ECORE allows long-term optical recording over multiple days.

scholarly journals Spread spectrum SERS allows label-free detection of attomolar neurotransmitters

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wonkyoung Lee ◽  
Byoung-Hoon Kang ◽  
Hyunwoo Yang ◽  
Moonseong Park ◽  
Ji Hyun Kwak ◽  
...  
Keyword(s):  
Spread Spectrum ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Surface Enhanced Raman Spectroscopy ◽  
Experimental Result ◽  
High Temporal Resolution ◽  
Label Free ◽  
Label Free Detection ◽  
Surface Enhanced Raman ◽  
Sers Detection

AbstractThe quantitative label-free detection of neurotransmitters provides critical clues in understanding neurological functions or disorders. However, the identification of neurotransmitters remains challenging for surface-enhanced Raman spectroscopy (SERS) due to the presence of noise. Here, we report spread spectrum SERS (ss-SERS) detection for the rapid quantification of neurotransmitters at the attomolar level by encoding excited light and decoding SERS signals with peak autocorrelation and near-zero cross-correlation. Compared to conventional SERS measurements, the experimental result of ss-SERS shows an exceptional improvement in the signal-to-noise ratio of more than three orders of magnitude, thus achieving a high temporal resolution of over one hundred times. The ss-SERS measurement further allows the attomolar SERS detection of dopamine, serotonin, acetylcholine, γ-aminobutyric acid, and glutamate without Raman reporters. This approach opens up opportunities not only for investigating the early diagnostics of neurological disorders or highly sensitive biomedical SERS applications but also for developing low-cost spectroscopic biosensing applications.

scholarly journals Label-free optical detection of bioelectric potentials using electrochromic thin films

2020 ◽  
Vol 117 (29) ◽  
pp. 17260-17268
Author(s):  
Felix S. Alfonso ◽  
Yuecheng Zhou ◽  
Erica Liu ◽  
Allister F. McGuire ◽  
Yang Yang ◽  
...  
Keyword(s):  
Thin Films ◽  
Brain Slices ◽  
Optical Probe ◽  
Optical Recording ◽  
Dorsal Root Ganglion Neurons ◽  
Frame Rate ◽  
Label Free ◽  
Spontaneous Action ◽  
Ganglion Neurons ◽  
Spontaneous Action Potentials

Understanding how a network of interconnected neurons receives, stores, and processes information in the human brain is one of the outstanding scientific challenges of our time. The ability to reliably detect neuroelectric activities is essential to addressing this challenge. Optical recording using voltage-sensitive fluorescent probes has provided unprecedented flexibility for choosing regions of interest in recording neuronal activities. However, when recording at a high frame rate such as 500 to 1,000 Hz, fluorescence-based voltage sensors often suffer from photobleaching and phototoxicity, which limit the recording duration. Here, we report an approach called electrochromic optical recording (ECORE) that achieves label-free optical recording of spontaneous neuroelectrical activities. ECORE utilizes the electrochromism of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) thin films, whose optical absorption can be modulated by an applied voltage. Being based on optical reflection instead of fluorescence, ECORE offers the flexibility of an optical probe without suffering from photobleaching or phototoxicity. Using ECORE, we optically recorded spontaneous action potentials in cardiomyocytes, cultured hippocampal and dorsal root ganglion neurons, and brain slices. With minimal perturbation to cells, ECORE allows long-term optical recording over multiple days.

scholarly journals The Role of Surface Chemistry in the Efficacy of Protein and DNA Microarrays for Label-Free Detection: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1026
Author(s):  
Elisa Chiodi ◽  
Allison M. Marn ◽  
Matthew T. Geib ◽  
M. Selim Ünlü
Keyword(s):  
Surface Chemistry ◽  
Surface Functionalization ◽  
Dna Microarrays ◽  
Label Free ◽  
Polymeric Coatings ◽  
Label Free Detection ◽  
Particle Imaging ◽  
Single Particle Imaging ◽  
The Impact

The importance of microarrays in diagnostics and medicine has drastically increased in the last few years. Nevertheless, the efficiency of a microarray-based assay intrinsically depends on the density and functionality of the biorecognition elements immobilized onto each sensor spot. Recently, researchers have put effort into developing new functionalization strategies and technologies which provide efficient immobilization and stability of any sort of molecule. Here, we present an overview of the most widely used methods of surface functionalization of microarray substrates, as well as the most recent advances in the field, and compare their performance in terms of optimal immobilization of the bioreceptor molecules. We focus on label-free microarrays and, in particular, we aim to describe the impact of surface chemistry on two types of microarray-based sensors: microarrays for single particle imaging and for label-free measurements of binding kinetics. Both protein and DNA microarrays are taken into consideration, and the effect of different polymeric coatings on the molecules’ functionalities is critically analyzed.

scholarly journals Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1872
Author(s):  
Holger Schulze ◽  
Harry Wilson ◽  
Ines Cara ◽  
Steven Carter ◽  
Edward N. Dyson ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Electrochemical Impedance ◽  
Point Of Care ◽  
Branched Polymers ◽  
Label Free ◽  
Conformation Change ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Staphylococcus Carnosus ◽  
Label Free Detection

Rapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability.

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