Experimental analysis of folic acid adsorption on TiO2 thin-films

TiO2 thin-films functionalized with specific biomolecules have been used in the fabrication of highly sensitive and selective electrochemical biosensors focused on detecting a variety of diseases. Among the biosensors of scientific and technological interest are those obtained from the functionalization of nanomaterials with folic acid to recognize folate receptors; their importance lies in the fact that these receptors are overexpressed in most abnormal cells, and their identification can allow the detection of tumor cells and the photothermal treatment of cancer. This work presents a methodology for fabricating TiO2 thin-films and functionalizing them with folic acid. X-ray photoelectron spectroscopy, atomic force microscopy, Raman spectroscopy, and contact angle measurements were used to examine the adsorption of folic acid on TiO2 thin-film surfaces grown by pulsed laser deposition. XPS and Raman analysis indicated that the interaction of folic acid with the TiO2 surface occurred either through the pteridine ring or through the carboxylic groups of the glutamic acid portion
The authors thank the I-COOP+2018 program of CSIC (Ref. No. COOPA20305) and Universidad Industrial de Santander for financial support. Furthermore, we would like to acknowledge teams of Laboratorio de ciencia de superficies and Laboratorio de Espectroscopia of the Parque Tecnológico de Guatiguará at Universidad Industrial de Santander for XPS and Raman analysis. The authors thank Yves Huttel from ICMM-CSIC for his help with additional XPS measurements.