A sandwich-type electrochemiluminescence aptasensor for insulin detection based on the nano-C60/BSA@luminol nanocomposite and ferrocene derivative

A highly sensitive and sandwiched electrochemiluminescence (ECL) aptasensor was proposed for detection of insulin by using fullerene nano-materials/bovine serum albumin@luminol (nano-C60/BSA@luminol) nanohybrid as signal probe. Herein, Ferrocenecarboxylic acid@aptamer II (Fc@aptamer II) and nano-C60/BSA@luminol nanocomposites were synthesized for the first time and applied to carry out dual-amplification strategy in the luminol-hydrogen peroxide (luminol-H2O2) system. Notably, nano-C60/BSA with large specific surface area and advantageous biocompatibility can enable high loading of luminol and further enhance ECL intensity. Furthermore, the obtained nano-C60/BSA@luminol nanohybrid was used as ECL signal probe owing to the presence of massive luminol and played an important role of acting as capture probe to recognize aptamer I. Besides, it is very crucial that Fc showed superior catalytic effect for H2O2, which generated more excited state luminol as well as strong ECL signal. Additionally, the as-prepared ECL aptasensor provided a wide linear range from 0.0001 to 1000 ng/mL and a low detection limit of 0.04 pg/mL (S/N = 3) and correlation coefficient (R2) was 0.993 for insulin. In conclusion, the as-proposed ECL aptasensor would open a new vista for sensitive detection of insulin and suggested favorable application prospect in bioanalysis.