A Simple, Rapid, and Highly Sensitive Electrochemical DNA Sensor for the Detection of α- and ß-Thalassemia in China.

BACKGROUND: Because of the life-consuming treatment and severe consequences associated with thalassemia, it is more effective to prevent than cure thalassemia. Rapid and sensitive detection is critical for controlling thalassemia. In this study, we developed a rapid and accurate test to genotype nondeletional α- and ß-thalassemia mutations by an electrochemical DNA sensor. METHODS: Screen-printed electrodes were used as electrochemical transducers for the sensor, in which the capture probe DNA was attached to the golden surface of the working electrode via an S-Au covalent bond, which is highly suitable for immobilizing the biological element. In addition, two types of ferrocene with varying redox potentials for modified signal probe DNA were adopted. The hybridization signal is detected by alternating current voltammetry when the capture probe and signal probe hybridize with the target DNA. RESULTS: With this technique, 12 types of nondeletional α- and ß-thalassemia mutations were detected, which constitute more than 90% of all the nondeletional types of thalassemia mutation determinants found in China, including the CD142 (TAA>CAA) Constand spring, CD125 (CTG>CCG) Quonsze, CD122 (CAC>CAG) Weastmead, -28 (A>G), Cap+1 (A>C), initiation codon (ATG>AGG), CD17 (AAG>TAG), CD26 (GAG>AAG), CD31(-C), CD41-42 (-CTTT), CD71-72 (+A), and IVS-II-654 (C>T) mutations. Concordance levels were 100% within the 20 blood samples of homozygous wild-type individuals and 238 blood samples of heterozygous mutant individuals. CONCLUSIONS: The electrochemical DNA sensor developed here can be applied for rapid genotyping of thalassemia or other clinical genotyping applications and is useful for early screening of thalassemia in high-risk groups by minimizing the time and investment cost.