▎ 摘　　要

NOVELTY - An intermediate comprising label-free bio barcoded gold nanoprobe, is new, where DNA1 and DNA2 are adsorbed on nanogold particles, the DNA 1 is diblock DNA comprising a section of 5-10 adenine bases for immobilizing DNA 1 on surface of gold nanoparticle and another section of recognition segment for specifically hybridizing the target small RNA, and the DNA2 comprises 5-10 adenine bases for closing site. USE - The intermediate is useful for preparing label-free magnetic graphene oxide-nanogold complex, which is used for detecting small RNA (claimed). ADVANTAGE - The intermediate has high speed, sensitivity and specificity in detecting small RNA. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) method (M1) for preparing label-free bio barcoded gold nanoprobe; (2) label-free magnetic graphene oxide-nanogold complex obtained by stacking recognition segment of DNA 1 and magnetic graphene oxide and adsorbing the intermediate to magnetic graphene oxide; (3) method (M2) for preparing label-free magnetic graphene oxide-nanogold complex involves mixing and reacting intermediate and magnetic graphene oxidie, magnetically separating mixture and removing unbound intermediates; and (4) method (M3) for detecting small RNA involves adding the magnetic graphene oxide-nanogold complex and target small RNA, where the complex has different adsorption capacity for single-stranded DNA and double-stranded DNA, and recognition segment of DNA1 specifically binds to the target small RNA to form DNA/RNA double-stranded structure, adsorbing magnetic graphene oxide on surface of gold nanoprobe solution, magnetically separating mixture, quantitative analyzing and observing color change of supernatant using UV-visible spectrophotometry.