Molecularly imprinted hydrogels embedded with two-dimensional photonic crystals for the detection of dexamethasone/betamethasone sodium phosphate.

Dexamethasone sodium phosphate (DSP) and betamethasone sodium phosphate (BSP) imprinted hydrogels embedded with two-dimensional photonic crystals (2DPC) were developed as hormones-sensitive photonic hydrogel sensors with highly sensitive, selective, anti-interference and reproducible recognition capability. The DSP/BSP molecularly imprinted photonic hydrogels (denoted as DSP-MIPH and BSP-MIPH) can specifically recognize DSP/BSP by rebinding the DSP/BET molecules to nanocavities in the hydrogel network. This recognition is enabled by the similar shape, size, and binding sites of the nanocavities to the target molecules. The rebinding of hormones molecules causes the hydrogel to swell, resulting in a particle spacing increase of the embedded 2DPC of the hydrogel. The particle spacing increase can be used as sensing signal and can be acquired by simply measuring the Debye diffraction diameters of the photonic hydrogel sensor before and after exposure with a laser pointer and a ruler. The particle spacing increments of the DSP-MIPH and BSP-MIPH sensors linearly change when DSP and BSP concentrations changes within the ranges 0.025-1 μM, 10-100 μM, and 100-500 μM, and the limits of detection (LoD) are 21.8 nM for DSP and 12.6 nM for BSP, respectively. These photonic hydrogel sensors were successfully applied to the determination of DSP/BSP contents in the real pharmaceutical injections, providing an ideal strategy for the development of portable hormones sensors.