Center-concave nanosheets of core-shell WO₃@Prussian blue based handheld microchip-devices for ultrasensitive lysine determination

Lysine is one of the essential amino acids for human body, and its imbalance is a major cause to anemia, aging process, leukemia cell proliferation and tumor growth. Therefore, its monitoring is dominative to the prevention the disease progress and guidance to the clinical treatment. However, traditional in-hospital detection methods, such as colorimetry and fluorometric, often suffer the disadvantages of high cost and long time-consuming. These drawbacks show a difficulty in the home-in and dairy monitoring for the lysine regulation in body. In this study, we have proposed an ultrasensitive microchip-based portable device to achieve the onsite and precise determination of lysine within only 10 s. This microchip was functionalized through constructing a center-concave nanosheet of core-shell WO₃@Prussian blue (WO₃@PB) to remarkably strengthen the generation and transfer of the detection signal. In this special architecture, the core WO₃ nanosheet can be exposed at the center region of this nanocomposite to effectively promote the enzymatic oxidation, while the PB shell enables to strongly reduce the H₂O₂ produced by the enzymatic reaction. Under above synergetic effects, a handheld device was designed to support the plug-and-play microchip, which performed an outstanding accuracy for the lysine detection in blood.