Preparation of a new apta-nanobiosensor based on fluorescence of cadmium telluride quantum dots coated with specific oligonucleotide polymers for rapid detection of Vitamin D3

کد مقاله : 1049-ICOC

نویسندگان

فرهاد تحریری * دانشگاه پیام نور

چکیده مقاله

Medical research has identified a strong correlation between vitamin D deficiency and various metabolic disorders, including diabetes, cardiovascular diseases, and cancer. Consequently, monitoring vitamin D levels in blood serum is imperative. Current methods for measuring 25-hydroxy vitamin D3 [25(OH)D3], a key indicator of vitamin D status, are often costly, time-consuming, and dependent on skilled technicians and specialized laboratories. In response to these challenges, this study introduces a straightforward, cost-effective fluorescence system for 25-hydroxyvitamin D3 analysis. This study include in two parts. In the first part of the study, the fluorescent APTA-nanobiosensors were fabricated using cadmium telluride quantum dots modified with thioglycolic acid (CdTe-TGA QDs) and functionalized with thiol-25(OH)D3-aptamer through ligand exchange. The aptamer directly interacted with the CdTe-TGA QDs, enhancing fluorescence intensity; however, this intensity decreased upon the introduction of 25-hydroxyvitamin D3 target molecules. The fluorescence quenching exhibited a linear relationship with the target concentration, based on the Stern-Volmer equation. The system achieved a detection limit (LOD) of 1.35 × 10⁻⁸ M, a quantification limit (LOQ) of 4.50 × 10⁻⁸ M, and a relative standard deviation of 1.75%. The optimized APTA-nanobiosensors indicated high specificity for the target molecule and maintained stability for up to 28 days. Additionally, they effectively quantified 25(OH)D3in human serum with a recovery rate of up to 99.77%. In the second part, the study focused on the APTA sensor/Cy3 probe, which was constructed using CdTe-TGA QDs, a thiol-25(OH)D3-aptamer label, and a label-free Cy3 aptamer. This system successfully detected 25(OH)D3 molecules. The fluorescence intensity was reduced due to the effective alignment between the emission spectrum of the CdTe QDs and the absorption spectrum of Cy3, enabling the FRET mechanism. 25(OH)D3 molecules effectively quenched the system when introduced, showing a clear linear relationship between fluorescence intensity and 25(OH)D3 concentration. The system achieved a LOD of 8.05 × 10⁻9 M and a LOQ of 2.68 × 10⁻8 M. The APTA-nano biosensor/Cy3 complex exhibited outstanding selectivity and specificity for 25(OH)D3, maintained stability for up to 28 days, and delivered a high recovery rate ranging from 96.00% to 100.88% when tested in human serum and urine using the spiking method. The structural and morphological properties of APTA-nanobiosensors were confirmed by diverse analytical techniques, including UV-visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The results illustrate the fluorescent APTA-nanobiosensors can be used as a reliable tool for detecting low-concentration.

کلیدواژه ها

Aptasensor, CdTe Quantum Dots, 25-hydroxy vitamin D3, Cy3, Fluorescent assay

وضعیت: پذیرفته شده