Issue 22, 2023

Light-up split aptamers: binding thermodynamics and kinetics for sensing

Abstract

Due to their programmable structures, many aptamers can be readily split into two halves while still retaining their target binding function. While split aptamers are prevalent in the biosensor field, fundamental studies of their binding are still lacking. In this work, we took advantage of the fluorescence enhancement property of a new aptamer named OTC5 that can bind to tetracycline antibiotics to compare various split aptamers with the full-length aptamer. The split aptamers were designed to have different stem lengths. Longer stem length aptamers showed similar dissociation constants (Kd) to the full-length aptamer, while a shorter stem construct showed an 85-fold increase in Kd. Temperature-dependent fluorescence measurements confirmed the lower thermostability of split aptamers. Isothermal titration calorimetry indicated that split aptamer binding can release more heat but have an even larger entropy loss. Finally, a colorimetric biosensor using gold nanoparticles was designed by pre-assembling two thiolated aptamer halves, which can then link gold nanoparticles to give a red-to-blue color change.

Graphical abstract: Light-up split aptamers: binding thermodynamics and kinetics for sensing

Supplementary files

Article information

Article type
Paper
Submitted
08 aug 2023
Accepted
14 sep 2023
First published
22 sep 2023

Analyst, 2023,148, 5612-5618

Light-up split aptamers: binding thermodynamics and kinetics for sensing

Y. Zhao, N. Patel, P. Sun, K. Faulds, D. Graham and J. Liu, Analyst, 2023, 148, 5612 DOI: 10.1039/D3AN01368E

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