Discrimination of Biothiols Using Ratiometric Fluorescence Sensor Array on Nanopaper Platform

Considering the crucial role of biothiols in many biological processes, which turns them into highly valuable biomarkers for early diagnosis of various diseases, the development of an affordable, sensitive and portable probe for identification and discrimination of these compounds is of great importance [1]. Here we developed ratiometric fluorescence (RF) sensor array [2] with a wide color emissive variation, on a bacterial cellulose (BC) nanopaper substrate for visual discrimination of biothiols. To this aim, RF sensing elements including N-Acetyl L-Cysteine capped green CdTe QDs -Rhodamin B (GQDs-RhB) and red CdTe QDs- Carbon dots (RQDs-CDs) at two different NaOH concentrations (0 and 5 mM) were utilized as sensor elements for the discrimination of biothiols. Owing to the high affinity of thiols group (SH) to the surface of CdTe QDs, the fluorescence (FL) emission of QDs changed while the emission of CDs and rhodamine B were remained almost unchanged upon the addition of biothiols. Accordingly, characteristic rainbow-like FL fingerprint patterns were created for each biothiols which were then distinguished both visually and spectroscopically. Hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA) pattern recognition techniques were employed for the identification and discrimination of biothiols. Bacterial cellulose nanopaper (BC) was chosen as a flexible and transparent substrate for developing convenient, rapid, sensitive and portable probe [3]. Therefore, based on the designed RF sensor array, convenient test strips. were fabricated on BC nanopaper for visual discrimination of biothiols. It has been shown that this probe can successfully identify biothiols in human plasma as well. Altogether, the developed nanopaper-based sensor array offers an efficient biothiols discrimination tool that can be potentially exploited in near future in theranostic and point-of-care applications.