Substrate-Induced Growth of Micro/Nanostructured Zn(OH)F Arrays for Highly Sensitive Microfluidic Fluorescence Assays

To date, ZnO array-based microfluidic fluorescence assays have been widely investigated and have exhibited excellent performance in the detection of cancer biomarkers. However, the requirements of highly sensitive detection necessitate further improvement of current Zn-based fluorescence detection devices. Here, a rhombus-like Zn(OH)F array-based microfluidic fluorescence detection device is proposed. Construction of Zn(OH)F arrays on the inner wall of a microchannel is carried out via a microfluidic chemical method. A substrate-induced growth strategy for Zn(OH)F arrays is proposed, and various micro/nanostructured Zn(OH)F arrays are successfully obtained. Zn(OH)F nanorod arrays with a high aspect ratio can be constructed on the columnar ZnO nanorod arrays, and the results indicate that the fluorescence enhancement factor (EF) of the Zn(OH)F arrays toward Cy3 is approximately 4-fold that of the ZnO nanorod arrays, which can be attributed to the higher excitation light absorption and evanescent electric field. In human epididymis-specific protein 4 (HE4) detection, the limit of detection (LOD) reaches 9.3 fM, and the dynamic linear range is 10 fM to 100 pM. It has been demonstrated that Zn(OH)F nanorod array-based microfluidic devices are excellent fluorescence assay platforms that also provide a new design and construction strategy for fluorescence enhancement substrates for the detection of biomarkers.

Automated summary

The study proposes a novel microfluidic fluorescence detection device based on rhombus-like Zn(OH)F array, achieving highly sensitive detection of cancer biomarkers. Various micro/nanostructured Zn(OH)F arrays are successfully obtained through a substrate-induced growth strategy. The detection limit reaches 9.3 fM with a dynamic linear range of 10 fM to 100 pM, demonstrating the potential of Zn(OH)F nanorod array-based microfluidic devices for biomarker detection.