Abstract
Monitoring membrane potential in neurons requires sensors with minimal invasiveness, high spatial and temporal (sub-ms) resolution, and large sensitivity for enabling detection of sub-threshold activities. While organic dyes and fluorescent proteins have been developed to possess voltage-sensing properties, photobleaching, cytotoxicity, low sensitivity, and low spatial resolution have obstructed further studies. Semiconductor nanoparticles (NPs), as prospective voltage sensors, have shown excellent sensitivity based on Quantum confined Stark effect (QCSE) at room temperature and at single particle level. Both theory and experiment have shown their voltage sensitivity can be increased significantly via material, bandgap, and structural engineering. Based on theoretical calculations, we synthesized one of the optimal candidates for voltage sensors: 12 nm type-II ZnSe/CdS nanorods (NRs), with an asymmetrically located seed. The voltage sensitivity and spectral shift were characterized in vitro using spectrally-resolved microscopy using electrodes grown by thin film deposition, which "sandwich" the NRs. We characterized multiple batches of such NRs and iteratively modified the synthesis to achieve higher voltage sensitivity (ΔF/F> 10%), larger spectral shift (>5 nm), better homogeneity, and better colloidal stability. Using a high throughput screening method, we were able to compare the voltage sensitivity of our NRs with commercial spherical quantum dots (QDs) with single particle statistics. Our method of high throughput screening with spectrally-resolved microscope also provides a versatile tool for studying single particles spectroscopy under field modulation.
Original language | English |
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Title of host publication | Biosensing and Nanomedicine X |
Editors | Manijeh Razeghi, Massoud H. Agahi, Massoud H. Agahi, Hooman Mohseni |
Publisher | SPIE |
ISBN (Electronic) | 9781510611610 |
DOIs | |
State | Published - 2017 |
Externally published | Yes |
Event | Biosensing and Nanomedicine X 2017 - San Diego, United States Duration: 6 Aug 2017 → 7 Aug 2017 |
Publication series
Name | Proceedings of SPIE - The International Society for Optical Engineering |
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Volume | 10352 |
ISSN (Print) | 0277-786X |
ISSN (Electronic) | 1996-756X |
Conference
Conference | Biosensing and Nanomedicine X 2017 |
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Country/Territory | United States |
City | San Diego |
Period | 6/08/17 → 7/08/17 |
Bibliographical note
Publisher Copyright:© 2107 SPIE.
Funding
We would like to thank Emory Chan for valuable discussion on NR syntheses and instruction on WANDA operation, Antonio Ingargiola for discussion on data analysis, and Max Ho and Wilson Lin for discussion on thin film fabrication. We thank Ocean Nanotech LLC for providing QDs at no cost. This research was supported by DARPA Fund #D14PC00141, by the European Research Council (ERC) advanced grant NVS #669941, and by the Human Frontier Science Program (HFSP) research grant #RGP0061/2015. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Funders | Funder number |
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Office of Basic Energy Sciences | |
U.S. Department of Energy | |
Defense Advanced Research Projects Agency | 14PC00141 |
Human Frontier Science Program | 0061/2015 |
Office of Science | |
European Commission | 669941 |
Keywords
- Quantum Dot
- action potential
- nanorod
- neuron
- quantum confined Stark effect
- voltage sensor