Description:	Since the report of the RNA aptamer for theophylline, theophylline has become a key molecule in chemical biology for designing RNA switches and riboswitches. In addition, theophylline is an important drug for treating airway diseases including asthma. The classic RNA aptamer with excellent selectivity for theophylline has been used to design biosensors, although DNA aptamers are more desirable for stability and cost considerations. In this work, we selected DNA aptamers for theophylline, and all the top sequences shared the same binding motifs. Binding was confirmed using isothermal titration calorimetry and a nuclease digestion assay, showing a dissociation constant (Kd) around 0.5 μM theophylline. The Theo2201 aptamer can be truncated down to 23-mer while still has a Kd of 9.8 μM. The selectivity for theophylline over caffeine is around 250,000-fold based on a strand-displacement assay, which was more than 20-fold higher compared to the classic RNA aptamer. For other tested analogs, the DNA aptamer also showed better selectivity. Using the structure-switching aptamer sensor design method, a detection limit of 17 nM theophylline was achieved in the selection buffer, and a detection limit of 31 nM was obtained in 10% serum.
Authors:	Huang, Po-Jung Jimmy; University of Waterloo; 0000-0003-3436-9968 Liu, Juewen; University of Waterloo; 0000-0001-5918-9336
Keywords:	DNA SELEX Aptamer Theophylline Biosensor RNA
Field of Research:	Biological sciences > Biochemistry > Analytical biochemistry
Publication Date:	2023-04-25
Publisher:	Federated Research Data Repository / dépôt fédéré de données de recherche
Funder:	Natural Sciences and Engineering Research Council Canada First Research Excellence Fund (CFREF); Global Water Futures Program (GWF)
URI:	https://doi.org/10.20383/102.0714
Related Identifiers:	This dataset is cited by https://doi.org/10.1021/acschembio.2c00179
Appears in Collections:	Water Institute