Photoelectrochemical biosensor detects bacteria fast

Illustration of the cross section of the photoelectrode showing the TiO 2 nanoparticles deposited on TiO 2 assemblies forming a co-sensitized semiconductor heterostructure. Inset shows a top-view scanning electron micrograph (SEM) of the photoelectrode surface. • Reagent- and culture-free sensor based on TiO 2 nanomaterials and synthetic DNA molecules detects harmful bacteria. • Assay is based on a highly sensitive and specific photoactive DNAzyme, a synthetic analogue of a natural protein enzyme. • DNAzyme assay is combined with TiO 2 nanomaterial electrodes to transduce the signal via photoelectrochemical reactions. • The PEC-DNAzyme-based biosensor can detect bacteria at low levels without the need for culture.