Binding of Apo and Glycated Human Serum Albumins to an Albumin-Selective Aptamer-Bound Graphene Quantum Dot Complex

Sirin Sittiwanichai; Jitti Niramitranon; Deanpen Japrung; Prapasiri Pongprayoon

doi:10.1021/acsomega.3c01595

Binding of Apo and Glycated Human Serum Albumins to an Albumin-Selective Aptamer-Bound Graphene Quantum Dot Complex

ACS Omega. 2023 Jun 6;8(24):21862-21870. doi: 10.1021/acsomega.3c01595. eCollection 2023 Jun 20.

Authors

Sirin Sittiwanichai¹, Jitti Niramitranon², Deanpen Japrung³, Prapasiri Pongprayoon^{1

4}

Affiliations

¹ Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand.
² Department of Computer Engineering, Kasetsart University, Chatuchak, Bangkok 10900, Thailand.
³ National Science and Technology Development Agency, National Nanotechnology Center, Thailand Science Park, Pathumthani 12120, Thailand.
⁴ Center for Advanced Studies in Nanotechnology for Chemical, Food and Agricultural Industries, KU Institute for Advanced Studies, Kasetsart University, Bangkok 10900, Thailand.

Abstract

Diabetes mellitus is a chronic metabolic disease involving continued elevated blood glucose levels. It is a leading cause of mortality and reduced life expectancy. Glycated human serum albumin (GHSA) has been reported to be a potential diabetes biomarker. A nanomaterial-based aptasensor is one of the effective techniques to detect GHSA. Graphene quantum dots (GQDs) have been widely used in aptasensors as an aptamer fluorescence quencher due to their high biocompatibility and sensitivity. GHSA-selective fluorescent aptamers are first quenched upon binding to GQDs. The presence of albumin targets results in the release of aptamers to albumin and consequently fluorescence recovery. To date, the molecular details on how GQDs interact with GHSA-selective aptamers and albumin remain limited, especially the interactions of an aptamer-bound GQD (GQDA) with an albumin. Thus, in this work, molecular dynamics simulations were used to reveal the binding mechanism of human serum albumin (HSA) and GHSA to GQDA. The results show the rapid and spontaneous assembly of albumin and GQDA. Multiple sites of albumins can accommodate both aptamers and GQDs. This suggests that the saturation of aptamers on GQDs is required for accurate albumin detection. Guanine and thymine are keys for albumin-aptamer clustering. GHSA gets denatured more than HSA. The presence of bound GQDA on GHSA widens the entrance of drug site I, resulting in the release of open-chain glucose. The insight obtained here will serve as a base for accurate GQD-based aptasensor design and development.