Early-phase nano-genosensing of cell-free nucleobiomarkers in the plasma of cancerous patients.

The extracted miR-21 and miR-155 from the plasma of clinical samples were targeted by non-crosslinking hybridization of Au-nanoprobes without the need for biomarker amplification. Thirty samples, including those suspected to cancer and chemotherapy-treated samples, were analyzed. An increase in the concentration of target biomarkers caused a blue-shift in the visible spectrum of nanoprobes. Using magnesium chloride, the change in the color of nanoprobes was shown to be dependent on time besides intensity. Samples with high averages of intensity needed less time for colorimetric differentiation than those with low average intensity. Au-nanoprobe-21 was turned to purple-gray in clinical specimens of stomach, colon, breast, esophagus, sarcoma, diaphragm, prostate, bladder, and lung while Au-nanoprobe-155 appeared as light purple-gray in colon, breast, lung, diaphragm and esophagus samples. The LOD was measured as 5 ng μL-1 of targeted biomarkers. The developed nano-biosensing method could propose a point-of-care approach for cancer prognosis and diagnosis, facilitating targeted therapeutics.