The surface-enhanced Raman spectroscopy (SERS) of blood serum was investigated to differentiate between prostate cancer (PCa) and benign prostatic hyperplasia (BPH) in males with a prostate-specific antigen level of 4–10 ng/mL, so as to reduce unnecessary biopsies. A total of 240 SERS spectra from blood serum were acquired from 40 PCa subjects and 40 BPH subjects who had all received prostate biopsies and were given a pathological diagnosis. Multivariate statistical techniques, including principal component analysis (PCA) and linear discriminant analysis (LDA) diagnostic algorithms, were used to analyze the spectra data of serum from patients in control (CTR), PCa and BPH groups; results offered a sensitivity of 97.5%, a specificity of 100.0%, a precision of 100.0% and an accuracy of 99.2% for CTR; a sensitivity of 90.0%, a specificity of 97.5%, a precision of 94.7% and an accuracy of 98.3% for BPH; a sensitivity of 95.0%, a specificity of 93.8%, a precision of 88.4% and an accuracy of 94.2% for PCa. Similarly, this technique can significantly differentiate low- and high-risk PCa with an accuracy of 92.3%, a specificity of 95% and a sensitivity of 89.5%. The results suggest that analyzing blood serum using SERS combined with PCA–LDA diagnostic algorithms is a promising clinical tool for PCa diagnosis and assessment.

Monitoring drug concentrations in vivo is very useful for adjusting a drug dosage during treatment and for drug research. Specifically, cutting-edge "on-line" drug research relies on knowing how drugs are metabolized or how they interact with the blood in real-time. Thus, this study explored performing in vivo Raman measurements of the model drug levofloxacin lactate in the blood using a nanoparticle-coated optical fiber probe (optical fiber nano-probe). The results show that we were able to measure real-time changes in the blood concentration of levofloxacin lactate, suggesting that this technique could be helpful for performing drug analyses and drug monitoring in a clinical setting without repeatedly withdrawing blood from patients.