Plasmonic sensing platform for C-reactive protein recognition via synthetic receptors decorated on graphene oxide and gold nanoparticles

C-reactive protein (CRP) level provides important information about the health status of the individual in predicting many diseases such as cardiovascular, chronic inflammatory, and neurodegenerative diseases. Therefore, determining CRP levels is important for correct health intervention and treatment follow-up. For the selective detection of CRP, we developed a (GO/Au-MIP) SPR sensor containing CRP-imprinted polymer modified with graphene oxide and gold nanoparticles. To prove the enhanced sensitivity of the sensor resulting from the presence of graphene oxide (GO) and gold nanoparticles (AuNPs), a CRP-imprinted (MIP) SPR sensor was prepared using the same method, excluding the incorporation of GO and AuNPs. In addition, a non-imprinted GO/Au-NIP SPR sensor was also prepared to evaluate the imprinting efficiency. In detecting CRP in PBS buffer, the GO/Au-MIP SPR sensor exhibited linearity in the concentration ranges of 0.1–2 ppm (R = 0.9721) and 5–100 ppm (R = 0.9740). The detection limit of the prepared sensor was calculated as 0.0082 ppm. In the study, the imprinting process efficiency was also evaluated by calculating the imprinting factor value (I.F=13.84). In the selectivity studies, the GO/Au-MIP SPR sensor was determined to be 9.23 times more selective against CRP protein than bovine serum albumin and 29.53 times more selective than hemoglobin. When the repeatability of the GO/Au-MIP SPR sensor was examined, it was determined that the GO/Au-MIP SPR sensor was able to detect CRP without any deterioration in performance in five consecutive reuses (RSD<1.5). Finally, CRP detection studies from the serum and urine solutions, which were selected as real samples, were carried out by the GO/Au-MIP SPR sensor to evaluate the matrix effect. CRP spiked serum sample was analyzed by the other standard method to validate the analytical results using CRP analyser.