Preconcentration and clean-up of sarcosine using molecularly imprinted polymer and fluorimetric detection: a sensitive strategy for prostate Cancer monitoring

Sarcosine ( N -methylglycine) has emerged as a promising biomarker for the early diagnosis of prostate cancer, allowing non-invasive detection in biological fluids and exhibiting greater specificity than PSA. In this study, a sarcosine-selective molecular fingerprinting polymer (MIP) was synthesized and applied as a selective sorbent in a dispersive solid-phase extraction (DSPE) system coupled with fluorimetric detection. This integrated strategy allows for the sensitive, selective, and low-cost determination of sarcosine in aqueous media and prostate cell lines, offering a simplified analytical alternative for biomarker monitoring. The MIP, obtained by block polymerization, was compared to the non-imprinted polymer (NIP) in terms of selectivity, adsorption capacity, kinetics, equilibrium isotherms, and reusability. The material showed a maximum adsorption capacity of 3.95 mg g −1 , approximately three times higher than that of the NIP (1.35 mg g −1 ), following a pseudo-second-order kinetic model and fitting the Freundlich and Scatchard isotherms. MIP also demonstrated high selectivity towards structural analogs, with selectivity factors up to eight times higher than those obtained for NIP. Solid-phase pre-concentration using MIP allowed for selective enrichment of sarcosine, increasing analytical sensitivity approximately ninefold. Optimized desorption with ACN/carbonate buffer (1:1, pH 10.5) resulted in detection and quantification limits of 0.060 and 0.019 mg L −1 , respectively. The polymer showed excellent stability and reusability over ten consecutive cycles without significant loss of performance. The methodology was applied to samples of healthy prostate cells (PNT-2) and tumor cells (LNCaP), with fluorimetric quantification validated by HPLC-UV. Sarcosine levels were significantly higher in tumor cells, with recoveries between 90% and 102%. These results confirm the robustness and potential of MIP for the selective detection of sarcosine in rapid diagnostic strategies. The proposed approach offers a simple and selective alternative to more complex chromatographic methods, with potential application in biomarker monitoring. • A molecularly imprinted polymer (MIP) selectively pre-concentrates sarcosine. • Fluorimetric detection enabled a nine-fold increase in analytical sensitivity. • The MIP demonstrated strong selectivity towards glycine, histidine, and biotin. • The limits of detection and quantification reached 0.060 and 0.019 mg L −1 , respectively. • The method successfully quantified sarcosine in prostate cell line samples. • Tumor cells showed sarcosine levels 4.6 to 7 times higher compared to healthy cells.