Instantaneous derivatization technology for the simultaneous and homogeneous detection of multiple double-stranded PCR amplicons

Abstract

Herein we report on the development of instantaneous derivatization technology for the homogeneous and simultaneous detection of multiple PCR amplicons specific to the Hepatitis B Virus (HBV) by using three carriers: magnetic beads, polystyrene beads, and thermo-sensitive poly-N-isopropylacrylamide (PNIP). Briefly, PCR amplicons are labeled with digoxin, biotin or FITC via the modified up-stream primers respectively. After PCR amplification, the immunoreactions occur between a mixture of three target PCR amplicons and three modified carriers with anti-digoxin antibody, streptavidin or anti-FITC antibody in a single vessel, and then each carrier is separated from the others under different conditions based on their physio-chemical attributes. And then direct CL detection proceeds via the instantaneous derivatization reaction between intrinsic guanine nucleobases and 3,4,5-trimethoxylphenylglyoxal (TMPG). This new protocol directly measures the double-stranded DNA and therefore does not require a denaturing step, thus offering an enhanced sensitivity due to the absence of competitive hybridization, i.e., the detection limit had a 20-fold improvement on the conventional PCR measurement. Additionally, by comparison of previous guanine based detection formats, this protocol is easy to be used for the detection of any guanine containing targets without the use of guanine-free or inosine-substituted capture probes. Overall, the proposed technique takes the advantages of sensitivity, high-speed and cost-effectivity, which provides a promising alternative for the analysis of multiple PCR targets in a variety of clinical, environmental, and biodefense fields.