Label-free biosensing of microRNA-423-5p in saliva sample of patients using KAUST catalysis center-1 modified dendritic AuNPs: a new platform towards early-stage diagnosis of oral cancer

Oral squamous cell carcinoma (OSCC) is the most prevalent form of oral cavity cancer and a leading cause of death globally with low survival rates. Early detection of OSCC is crucial for reducing morbidity and mortality. The microRNA-423-5p, a 23-nucleotide non-coding RNA, is a vital biomarker for accurate OC detection due to its high value in the Receiver Operating Characteristic (ROC) curve, ensuring selectivity for OC. A precise measurement of microRNA-423-5p in human biofluids facilitates accurate OC detection. This research introduces a novel electrochemical platform without the need for labeling, designed for the non-intrusive monitoring of microRNA-423-5p in human saliva samples using a DNA-based bioassay. In this approach, poly(β-cyclodextrin) was fabricated to serve as a biocompatible support on the glassy carbon electrode surface. Furthermore, KCC-1-nPr-NH-Arg, featuring a surface area of 104.9 m² g^-1 and a pore volume of 0.83 cm³ g^-1, was utilized to enhance the substrate's surface area relative to volume and achieve high loading of probe DNA (pDNA). For the first time, dendritic AuNPs were used to immobilize thiolated DNA sequences (5'-SH-TGTCTCCCCGGTGTCTGGCTCGA-3') on an electrode surface of electrode <i>via</i> Au-S interaction to detect microRNA-423-5p in human saliva in low limit of quantification of 1 pM. The biosensor successfully detected microRNA-423-5p, demonstrating its potential for OC screening. The genosensor development involved assessing crucial factors such as hybridization time and microRNA concentration. Analytical techniques including cyclic voltammetry, chronoamperometry, and differential pulse voltammetry were used for quantifying MicroRNA-423-5p in human biofluids. The biosensor's performance characteristics were evaluated for stability, repeatability, and suitability for plasma and saliva samples.