Quantification of uric acid concentration in tears by using PDMS inverse opal structure surface-enhanced Raman scattering substrates: Application in hyperuricemia

Hyperuricemia is closely related to a variety of diseases and has been listed as one of the twenty most persistent diseases in the 21st century by the United Nations. Therefore, strengthening the diagnosis of hyperuricemia has become imperative. Here, ordered inverse opal array structures (PAANs) composed of PDMS and gold nanoparticles (AuNPs) have been designed using a bottom-up self-assembly method. The structures exhibit a periodic distribution of hot spots, an enhancement factor (EF) of 4.22 × 104, and a relative standard deviation (RSD) of signal intensity of less than 5%, which can provide high reproducibility of SERS signals. The PAANs substrate is used to detect uric acid in the tears of patients with hyperuricemia, and the limit of detection is 6.03 μM. The significant linear relationship between blood uric acid and tear uric acid indicates that the developed method is a rapid, effective, and non-invasive technique for the determination of uric acid in tears.