A phenylboronic-acid functionalized liquid photonic crystal reagent for convenient and reliable detection of glucose

Photonic crystal sensing is an emerging technique that directly indicates the physicochemical changes with the change of structural color. However, there are still challenges in material synthesis, ease of use, and reproducibility of detection for traditional photonic crystal (PC) sensors. Here, a phenylboronic-acid functionalized SiO₂ liquid photonic crystal (PBA-LPC) reagent was developed for reliable detection of glucose concentration. It is convenient to prepare/use the LPC reagent because people only need to mix the responsive substance or the analyte solution with the LPCs in synthesis/detection. The sensing was based on the mechanism that the mixing of PBA-LPC reagent with glucose could release H⁺ cations from PBA, which inhibited the deprotonation of the silanol group, weakened the particle surface charge, and blue-shifted the reflection of LPC. The PBALPC reagents responded to the glucose in different concentration ranges depending on the dosage of PBA, which ensured both a broad range detection and an accurate detection within a specific range. Meanwhile, it reported reproducible results due to the precise introduction of PBA and its sufficient interaction with glucose. Furthermore, the PBA-LPC reagent showed a selective response to glucose and good anti-interference capability against the presence of NaCl, CaSO₄, KH₂PO₄, and Vitamin C. Due to these properties, the PBA-LPC reagent could serve as a new material for blood sugar tests and it also demonstrated the great potential of LPCs in sensing applications.