TY - JOUR
T1 - Detection of Molecules and Charges with a Bright Field Optical Microscope
AU - Zhu, Hao
AU - Ma, Guangzhong
AU - Wan, Zijian
AU - Wang, Hui
AU - Tao, Nongjian
N1 - Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/4/21
Y1 - 2020/4/21
N2 - Charge is a fundamental property of a molecule, and precisely measuring it enables detection of the molecule and helps understand various chemical processes involving charge. Here we show a method to measure the charge of a single nanoparticle and binding of charged molecules to the nanoparticle using a conventional bright field optical microscope. The nanoparticle is tethered to an indium tin oxide surface with a polymer and driven into oscillation with an alternating electric field, which produces scattered light captured by a camera. The weak scattered light is separated from the intense bright field background using a Fourier transform filter, and the image contrast change provides the effective charge of the nanoparticle with precision of a few electron charges or less. This method allows us to detect DNA binding to the nanoparticles, demonstrating a simple method to detect and study molecules with a conventional optical microscope.
AB - Charge is a fundamental property of a molecule, and precisely measuring it enables detection of the molecule and helps understand various chemical processes involving charge. Here we show a method to measure the charge of a single nanoparticle and binding of charged molecules to the nanoparticle using a conventional bright field optical microscope. The nanoparticle is tethered to an indium tin oxide surface with a polymer and driven into oscillation with an alternating electric field, which produces scattered light captured by a camera. The weak scattered light is separated from the intense bright field background using a Fourier transform filter, and the image contrast change provides the effective charge of the nanoparticle with precision of a few electron charges or less. This method allows us to detect DNA binding to the nanoparticles, demonstrating a simple method to detect and study molecules with a conventional optical microscope.
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U2 - 10.1021/acs.analchem.9b05750
DO - 10.1021/acs.analchem.9b05750
M3 - Article
AN - SCOPUS:85084647458
SN - 0003-2700
VL - 92
SP - 5904
EP - 5909
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 8
ER -