A carboxylated graphene and aptamer nanocomposite-based aptasensor for sensitive and specific detection of hemin

•A nanocomposite-based biosensor was constructed by grafting an aptamer onto COO-GR.•COO-GR is advantageous in simplifying sensor preparation.•SWV was employed to realize selective and specific hemin detection.

A unique nanocomposite was crafted by grafting hemin-binding-aptamer (HBA) onto carboxylated graphene (COO-GR). Infrared spectroscopy, Raman spectroscopy and diffuse reflectance spectra suggested that –NHCO– covalent bonds were formed between HBA and COO-GR. The resulting COO-GR/HBA functionalized electrode was used as a novel label-free biosensor. The square wave voltammetry was employed to realize the selective and specific detection of hemin. The obtained aptasensor possessed excellent performance with a detection limit of 0.64 nmol L−1 (S/N=3) and a linear range from 1 to 150 nmol L−1. Moreover, COO-GR was shown to be a promising candidate in making aptasensors, carrying advantages over graphene in terms of the simplicity of sensor preparation and the reduction of background noise.

Graphical abstractAn aptasensor constructed by grafting hemin-binding-aptamer (HBA) onto carboxylated graphene (COO-GR) was used to selectively and specifically detect hemin. With the advantage over graphene in simplifying sensor preparation and reducing background noise, the resulting aptasensor possesses excellent performance with a detection limit of 0.64 nmol L−1 (S/N=3) and a linear range from 1 to 150 nmol L−1.Figure optionsDownload full-size imageDownload as PowerPoint slide