Rapid Detection of Tumor Necrosis Factor-Alpha Using Quantum Dot-Based Optical Aptasensor.

This paper reports an optical “TURN OFF” aptasensor, which is comprised of a deoxyribonucleic acid aptamer attached to a quantum dot on the $5^{\prime }$ terminus and gold nanoparticle on the $3^{\prime }$ terminus. The photoluminescence intensity is observed to decrease upon progressive addition of the target protein tumor necrosis factor-alpha (TNF- $\alpha $) to the sensor. For PBS-based TNF- $\alpha $ samples, the beacon exhibited 19%–20% quenching at around 22 nM concentration. The photoluminescence intensity and the quenching efficiency showed a linear decrease and a linear increase, respectively, between 0 to 22.3 nM TNF- $\alpha $. The detection limit of the sensor was found to be 97.2 pM. Specificity test results determined that the sensor has higher selectivity toward TNF- $\alpha $ than other control proteins such as C—reactive protein, albumin, and transferrin. The beacon successfully detected different concentrations of TNF- $\alpha $ in human serum-based samples exhibiting around 10% quenching efficiency at 12.5 nM of the protein. [ABSTRACT FROM AUTHOR]