Development of electrochemical DNA biosensor based on 30 nm gold nanoparticle modified electrode by electro less deposition for HPV 18

Abstract

Biosensor is one of the best ways of sensing biomolecules samples. The developed of Interdigitated (IDE) biosensor provide a good detection of Human Papillomavirus. Thus this research project is focused on the development of biosensor by using 30 nm of the gold nanoparticle to enhance signal and improve in sensing biomolecules in detecting HPV 18. In this research, a 5 μm gap of IDE has been used in developing the biosensor. Moreover, the performance of the devices was tested by evaluating the capacitance and impedance reading by sweeping a frequency from 1M Hz to 0.1 Hz at room temperature with 1.0 mV input using Dielectric Analyzer. The IDE were first modified with 30 nm of a gold nanoparticle, followed by dropped of mercapto on to IDE to block gold nanoparticle. Then, continued with functionalization with APTES. Furthermore, immobilization of DNA probe with HPV 18 and lastly, hybridization with target DNA by distinguishing the impedance value between complementary, non-complementary and single mismatch DNA sequences. For sensitivity test, a different concentration of complementary target starting from 1 μM, 1 nM, 1 pM, and lastly 1 fM has been prepared to identify the lowest concentration of target can be detected by the biosensor. The result obtained that the complementary target after hybridization has showed a positive detection. While for non-complementary and mismatch target, the result showed the negative detection of HPV virus. Besides, the result of characterization of 30 nm gold nanoparticle and probe HPV 18 has showed a blurry image by using Scanning Electron Microscopy (SEM). Lastly, the performance of IDE biosensor has successfully detected the virus up to Pico Molar concentration. As a conclusion, the device has successfully worked as biosensor over a various range of target DNA concentration (1μM to 1 fM). The lower detection limit was achieved at 1 pM concentration of HPV 18 DNA target against the probe sequence.