The Responsive Photonic Crystal Film Sensor for Ultrasensitive Detection of Uranyl Ions
As an effective nuclear resource, uranium plays an important role in industry and energy, but the wastes of uranium also produce radioactive contamination which are harmful to the environment and human body. Herein, a responsive photonic crystal (PC) film sensor for the ultrasensitive and label-free detection of uranyl ions (UO22+) has been proposed, which is easy to construct and does not need to combine with hydrogel. The PC film is non-pH sensitive because is obtained by the self-assembly of methyl methacrylate-acrylonitrile co-polymeric nanospheres (PMMA-AN). These nanospheres are modified with amidoxime groups which have a good coordination ability with UO22+. The bindings between nanospheres and UO22+ change the refractive index and disturb the face centered cubic structure of the film, that leads to a decrease of the diffraction peak intensity of the PC film. The sensor works in the range of 10 pM to 100 μM for UO22+ determination, and the decreased intensities of the diffraction peaks are linearly correlated with the logarithm of the UO22+ concentration from 1nM to 100 μM. Moreover, the sensor shows a good selectivity for UO22+, and can also perform the determination of UO22+ in real sample. The responsive PC film sensor shows great potential in label-free and ultrasensitive detection of UO22+.