Affinity Recognition Based Gravimetric Nanosensor for Equilin Detection
Citation
Gülgün Aylaz 1,2 and Müge Andaç 3,* 1 Graduate School of Science and Engineering, Hacettepe University, Beytepe, Ankara 06800, Turkey; gulgunaylaz@gmail.com 2 Nanotechnology and Nanomedicine Division, Hacettepe University, Beytepe, Ankara 06800, Turkey 3 Environmental Engineering Department, Hacettepe University, BeyAbstract
The estrogenic hormones that are widely used in postmenopausal hormone supplements
for women contaminate natural water resources. Equilin (Equ) is one of the estrogenic hormones
that have a maximum contaminant level of 0.35 g/L in the chemical pollutants list. In this study,
estrogenic hormones were precisely detected in a short time by affinity-recognition-based interactions
in Quartz Crystal Microbalance (QCM) sensors. The QCM sensors were modified with
11-mercaptoundecanoic acid forming a self-assembled monolayer and with amino acids, namely
tyrosine, tryptophan and phenylalanine. The affinity interactions between Equ and amino acids were
studied using docking tools and confirmed by QCM experiments. The LODs of Equ were obtained as
4.59, 5.05 and 6.30 ng/L for tyrosine-, tryptophan- and phenylalanine-modified QCM nanosensors,
respectively, with linear dynamic detection in the range of 25–500 nM. In terms of the LOD, selectivity
and sensitivity calculations, the tyrosine-modified QCM nanosensor was found to have the highest
performance for Equ detection compared to the tryptophan- and phenylalanine-modified ones.