Detection of carbamazepine in saliva based on surface-enhanced Raman spectroscopy.

Carbamazepine (CBZ) is a commonly used drug for the treatment of epilepsy. Due to the narrow effective range, CBZ concentration was usually monitored with blood draw from patients. Frequent blood draw is inconvenient and causes physical and psychological pain. Therefore, highly-sensitive, rapid, label-free, and non-invasive drug detection methods can be alternatives to bring a relief. In this work, we have proposed a method for the non-invasive detection of CBZ using surface-enhanced Raman spectroscopy (SERS). Gold-silver core-shell nanomaterial substrates were prepared and optimized. Salivary CBZ concentration was measured with SERS as a non-invasive alternative to blood draw. The results showed that there was a linear relationship between SERS response and CBZ concentration in the entire measured range of 10-1 ∼ 10-8 mol/L. The detection limit of this method was 1.26 × 10-9 mol/L. Satisfactory repeatability and stability were also demonstrated. Due to its high sensitivity and ease of operation, the proposed method can serve as an alternative to blood draw for non-invasively monitoring CBZ concentration. It also has great potentials in many other applications of biomedical sciences.