A high-performance interdigitated electrode (IDE) biosensing surface was reported here by utilizing self-assembled silica nanoparticle (SiNP). The modified surface was used to evaluate the complementation of hairpin forming region from Mitoxantrone resistance gene 7 (MXR7; liver cancer-related short gene). The conjugated SiNPs on 3-aminopropyl triethoxysilane functionalization were captured with probe sequence on IDE biosensing surface. The physical and chemically modified surface was used to quantify MXR7 and an increment in the current response upon complementation was noticed. Limit of target DNA detection was calculated (1-10 fM) and this label-free detection is at the comparable level to the fluorescent-based sensing. A linear regression was calculated [y = 0.243x - 0.0773; R² = 0.9336] and the sensitivity was 1 fM on the linear range of 1 fM to 10 pM. With the strong attachment of capture DNA on IDE through SiNP, the surface clearly discriminates the specificity (complementary) versus nonspecificity (complete-, single-, and triple-mismatched sequences). This detection strategy helps to determine liver cancer progression and the similar strategy can be followed for other gene sequence complementation.
Keywords: DNA sensor; interdigitated electrode; liver cancer; silica nanoparticle.
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