Dopamine modified hyperbranched TiO 2 arrays based ultrasensitive photoelectrochemical immunosensor for detecting neuron specific enolase.

In this work, three-dimensional (3D) hyperbranched TiO2 nanorod arrays were synthesized and used to fabricate dopamine sensitized photoelectrochemical (PEC) biosensor. To increase the lifetime of charge carriers and enhance the photocurrent responses signal, a delicate signal amplification strategy by introducing dopamine (DA) as sensitizer was developed. The dopamine sensitized TiO2 can shorten the carrier diffusion distance, improve light harvesting efficiency and charge collection efficiency, which results in performance improvement of the as-obtained PEC sensor. This proposed biosensor for determination of neuron specific enolase (NSE) demonstrated a good linear relationship range from 0.1 ng mL-1 to 1000 ng mL-1 with a detection limit of 0.05 ngmL-1 (S/N = 3). In addition, the as-prepared immunosensor exhibits excellent selectivity, stability and reproducibility, which could be extended to other label-free sensing fields. Therefore, this proposed method may also provide potential applications for the clinical examination.