Research Information System
Nanoscience and Nanotechnology Conference, İzmir, Turkey, 27 - 30 August 2023, (Unpublished)
Lateral flow immunoassay (LFIA) is a point-of-care (POC), easy-to-use, cost-effective, and rapid diagnostic method to detect the target analytes in samples including whole blood, plasma, serum, sweat, or urine. Analyzing the analyte under laboratory conditions is time-consuming and expensive, whereas immunochromatographic analyzes are affordable, provide results in minutes, and do not require any professional during analysis. An optical system for immunochromatography can indicate the stage of a certain disease in addition to presence/absence binary detection, which can be significantly life-saving, especially in patients who need immediate treatment in the emergency department. In this study, the optical imaging system for LFIAs is developed based on CdTe quantum dots (QD) which were selected due to their niche properties for bioimaging including water solubility, high photoluminescence (PL) quantum yield (QYs), longer decay times and photostability. Observed samples were classified into 2 categories: (1) aqueous forms of 1:1, 1:2, 1:10, and 1:100 dilutions of CdTe QD with a stock concentration of 3.5 mg/ml diluted with borate buffer at pH 7.5, and (2) dry forms embedded in conjugate pads (fiberglass) with a volume of 4 µl at the same dilutions. In the setup consisting of a 405-nm light source, sample holder, 490-nm LP dichroic-mirror, and photodetector, the light source was chosen as LED in order to prevent saturation encountered in the photodetector. Comparative analysis reveals a significant reduction of the QD emission in the glass fiber medium, by a factor of 21.27 (tubes: 0.3106 a.u., strips: 0.0146 a.u.) when compared to CdTe QDaqueous. Nevertheless, the usage of a more intense 405-nm laser light source has resulted in a spectacular 967.8% increase in PL Intensity observation for QDdry (0.1558 a.u.). As QD concentration increases, aggregation-induced emission is observed, which may play an important role in determining the level of disease in the body with the red-shifted emission spectra. The half-life of the strips was determined as 13 days. Data that could not be obtained in X-Ray Diffractometry (XRD) due to the very small conjugated pads with sample embedded and in the spectrofluorometer since the pores in the fiberglass scatter light were obtained in this setup, and this study offers promising potential for next-generation rapid diagnosis and diagnostics.