Determination of circulating tumor cells by surface-enhanced Raman scattering based on molecularly imprinted polymers doped with silver nanoparticles

The rapid and simple detection of circulating tumor cells (CTCs) can help with early diagnosis of tumor diseases and assist clinical judgment of tumor disease development status and prognosis. An important alteration in cancer progression is a significant increase in sialic acid (SA) levels, making sialic acid one of an interesting biomarker for cancer type diversity. Here, novel SERS nano-biosensors were fabricated employing molecularly imprinted polymers (MIPs) particles loaded with Ag nanoparticles (AgNPs) to form high affinity toward sialic acid on CTCs. In this work, the glycol-specific MIPs are produced using precipitation polymerization. The nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR), zeta potential, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Consequently, CTC can be rapidly detected in mouse blood in a specific and sensitive manner, as low as 1 cells/ml. In addition, a good linear relationship was observed between CTC concentration and signal intensity (R2 = 0.9881). Moreover, the SERS nano-biosensors was used to detect CTC with excellent precision (relative standard deviation, RSD = 3.9%) and good repeatability (RSD = 6.8%). Therefore, this inexpensive, highly sensitive, and rapid method using SERS nano-biosensors can quickly detect CTCs and may prove to be a new platform to be an early diagnostic tool for cancer patient detection.