High-resolution light-activated electrochemistry on amorphous silicon-based photoelectrodes

Abstract

<p>The spatial resolution of silicon photoelectrochemistry is improved to 500 nm by using amorphous silicon, 60 times improvement as compared to crystalline silicon.</p>

Surface Patterning of Biomolecules Using Click Chemistry and Light‐Activated Electrochemistry to Locally Generate Cu(I)

“…Our work presents an approach that uses light patterns to diminish the time of surface patterning to within couple of hours. Furthermore, with the recent improvement of spatial resolution of LAE to the sub‐micron [23] scale, localized CuAAC shows great promise in high‐resolution mask‐less surface patterning. With extreme selectivity, robustness, and orthogonality of CuAAC, this technique can even be applied for initiating CuAAC in living cells using a probe activated with near infrared light opening new avenues in biological studies.…”

“…For LAE, 1 μm thick a‐Si on top of highly doped p‐type crystalline silicon pSi (100) was chosen for its biocompatibility [22] and high spatial resolution (500 nm) because a‐Si confines charge carriers within the illuminated region due to its short lateral charge diffusion [23] . HF etched a‐Si surface was thermally hydrosilylated to form SAMs with α,ω‐diyne (1,8‐nonadiyne) whose one end reacted with a‐Si to form Si−C=C bond to bestow stability against oxidation while the other distal end was free for CuAAC‐based conjugation (Figure 1, S2).…”

Light-Addressable Electrochemical Sensors toward Spatially Resolved Biosensing and Imaging Applications

“…Three models for the measurement of the lateral diffusion of light-generated charge carriers. The resolution is determined from the corresponding photocurrent line scan across an inert polymer pattern of SU-8 (a), electroactive bands of ferrocene (b), and an SECM tip current line scan on a nonpatterned ferrocene film (c). (c) Reprinted with permission from ref .…”

Monitoring the heterogeneity in single cell responses to drugs using electrochemical impedance and electrochemical noise

“…25 We have explored fundamental aspects of this concept, referred to as light activated electrochemistry, 23 including the impact of light intensity, 26 orientation of the light beam 27 and the thickness 28 and crystallinity 29 of the silicon on the spatial resolution that can be achieved and show that spatial resolutions below that needed to interrogate a single cell can be achieved. 27,29 We have also shown that this technique can be used to release rare single cells captured on an unpatterned surface, 3 and the detection of ion release from single cells, combined with uorescence microscopy can be used to show how the cells respond to drug treatment. 30 Herein we further show it is possible to perform conventional impedance measurements on single cells that are located anywhere on the silicon electrode surface.…”

“…This excitation of photoelectrons causes an increase in minority charge carriers in the silicon and hence an increase in conductivity around the site of illumination. 25 We have explored fundamental aspects of this concept, referred to as light activated electrochemistry, 23 including the impact of light intensity, 26 orientation of the light beam 27 and the thickness 28 and crystallinity 29 of the silicon on the spatial resolution that can be achieved and show that spatial resolutions below that needed to interrogate a single cell can be achieved. 27,29 We have also shown that this technique can be used to release rare single cells captured on an unpatterned surface, 3 and the detection of ion release from single cells, combined with fluorescence microscopy can be used to show how the cells respond to drug treatment.…”