Ultrasmall VOx nanoparticle as low-cost photothermal nanoprobe for enzyme-based biodetection.

[Display omitted] • Present the first example of ultrasmall photothermal nanoprobe, VO x nanoparticle, for enzyme-based biodetection. • The ultrasmall nanoprobe has higher reactivity and allows faster biodetection than the large-size nanoprobes. • Our photothermal methods only use one enzyme for biorecognition and low-cost device for read out. Low-cost photothermal probes facilitate the practical application of photothermal detection. However, current photothermal nanoprobes are generally larger in size and thus have slower reactivity with analytes, which is not conducive to rapid testing. Therefore, ultra-small photothermal nanoprobes would be preferred but have not been reported. Here, the ultrasmall VO x nanoparticle is constructed as low-cost photothermal nanoprobe, which is more reactive to H 2 O 2 and thus has reduced response time. In cooperation with enzymes, this nanoprobe can be used for photothermal detection of other biomolecules, such as glucose and uric acid. Compare with the standard colorimetric method, the photothermal method with ultrasmall VO x nanoparticle has high similarity and low analytical error of less than 5 %, which is sufficient for actual practice. [ABSTRACT FROM AUTHOR]