The Preparation of an Optical Hydrogen Peroxide Sensor Using Polydopamine as a Sensing Medium.

Polydopamine (PDA) is well known as an excellent coating material. It has various novel properties such as good biocompatibility, biodegradability, nontoxicity, easiness of deposit on all types of substrates, and strong stability as a primary natural pigment. In this research, in situ preparation of fluorescent PDA was performed by the addition of hydrogen peroxide (H₂O₂) to dopamine (DA) in the presence of Cu²⁺. DA does not show any fluorescence while the in situ self-initiated PDA has a strong fluorescence at 480 nm with excitation wavelength ranged from 330 nm to 420 nm due to the oxidation of DA by H₂O₂. A novel H₂O₂ sensor was fabricated using PDA as a fluorescence sensing medium. High sensitivity and linear response were achieved with a detection limit of 0.7 μM. The sensing medium is not toxic and allows biodegradation, which indicates high potential for in vivo application.