We have developed a quantum dot aptasensor (QD-aptasensor) and its accompanying portable analyzer for the detection of di-2-ethylhexyl phthalate (DEHP). This sensor is based on a newly screened aptamer (60-mer) via SELEX and shows a binding affinity of 213 nmol/L with DEHP. The 60-mer aptamer together with its three shorter truncated aptamers (45, 28, and 22-mer) as well as three different DNA probes (12, 9, and 13-mer) were further investigated to form the best combination for the QD-aptasensor. Using a 22-mer-truncated aptamer and a 12-mer DNA probe combination, the QD-aptasensor demonstrated excellent DEHP sensitivity with an LOQ = 0.5 pg/mL as well as good selectivity in the presence of other phthalate analogs. The binding between the truncated aptamers and DEHP was also characterized. Finally, a QD-aptasensor-based portable analyzer was also developed, and its equivalence to the laboratory protocol was established with a correlation coefficient r = 0.86 for DEHP concentrations ranging from 0.0005 to 100 ng/mL.
Bibliographical noteFunding Information:
This work was supported by the Ministry of Science, ICT, and Future Planning in Korea , Republic of Korea ( 2015M3C8A6A06012735 ) and the Korean National Research Foundation , Republic of Korea ( NRF-2017R1A2B4005133 ).
© 2018 Elsevier B.V.
- Di-2-ethylhexyl phthalate
- Portable analyzer
- Quantum dot aptasensor