Construction of nanoreactors on TiO2 nanotube arrays as a POCT device for sensitive colorimetric detection

With increasing attention to personalized healthcare, miniaturized and easily implementable devices are desired for point-of-care testing (POCT). Herein, hydrophilic patterns were designed on freestanding TiO2 nanotube arrays (TiNTs) as nanoreactors for a naked-eye colorimetric assay. With a high aspect ratio, TiNTs can provide a long observation length combined with a limited volume. Moreover, by combining the photocatalytic property of TiO2 and spatiotemporal controllability of light, hydrophilic nanoreactors were fabricated with minimal volume, and thus the indicator and analyte are limited in a confined void by the hydrophobic surroundings, thus allowing a higher sensitivity for sensing. We believe the proposed sensing platform could provide a promising strategy in developing POCT devices for routine health monitoring.