miRNA identification by nuclease digestion in ELISA for diagnosis of osteosarcoma

Osteosarcoma is a bone cancer formed by the cells of the bone. Children, young adults, and teens are highly affected by osteosarcoma. Early identification of osteosarcoma is mandatory to improve the treatment and increase the lifespan of the patients. MicroRNA-195 (miR-195) was shown to be a suitable biomarker for osteosarcoma, and the present study describes a sensitive method of miR-195 identification by nuclease digestion in ELISA to detect and quantify the level of miR-195. S1 nuclease catalyzed endo- and exonucleolytic digestion of single-stranded (ss) RNA and DNA on ELISA polystyrene substrate, which helped to identify duplexed miR-195. This method selectively and specifically identified miR-195 without any biofouling interactions and reached the limit of detection at 10 fM within the range from 10 fM to 10 nM. Due to complete digestion of ssDNA, single- and triple-mismatched sequences failed to increase the ELISA signal, indicating specific miRNA detection. Furthermore, human serum spiked with miR-195 did not interfere with the detection, confirming selective identification. This method identified miR-195 at a lower level and will help to diagnose earlier stages of osteosarcoma.