Highly sensitive l-lysine molecularly imprinted two-dimensional photonic crystal hydrogel sensor

Using polystyrene two-dimensional photonic crystal as template, l-lysine molecularly imprinted two-dimensional photonic crystal hydrogel (l-Lys MIPCH) sensor with highly sensitive response to l-lysine was prepared by photoinitiated polymerization. The response performance of the l-Lys MIPCH sensor was investigated by observing the change of the diameter of the Debye ring (ΔD) and the structural color of the sensor. In the process of recognizing l-Lys molecules by l-Lys MIPCH sensor, the volume of hydrogel swells, the diameter of Debye ring decreases, and the particle spacing of photonic crystal increases. As the l-Lys concentration increased from 0 to 10⁻⁴mol/L, the diameter of Debye ring decreased by 15.7 mm, the particle spacing of photonic crystals increased by 75.1 mm, and the structural color of hydrogel changed from blue to red correspondingly. When the l-Lys concentration was in the range of 10⁻¹²–10⁻⁴mol/L, there was a linear relationship between the change in the diameter of the Debye ring (ΔD) and the logarithm value of the l-Lys concentration (lgc), and the linear relationship was as follows: ΔD = 19.04 + 0.90 lgc, R²=0.9962. In addition, the detection limit of the sensor is as low as 10⁻¹⁶ mol/L. The prepared sensor not only has high selectivity, but also can be used for chiral recognition of l-Lys, and the results of l-Lys in the actual sample of lysiinositol vitamin B₁₂ oral solution were also satisfactory.