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TiO 2 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 TiO 2 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 TiO 2 thin-film surfaces grown by pulsed laser deposition. XPS and Raman analysis indicated that the interaction of folic acid with the TiO 2 surface occurred either through the pteridine ring or through the carboxylic groups of the glutamic acid portion. [ABSTRACT FROM AUTHOR]

Gold nanoparticles functionalized with folic acid toward the internalization into cancer cells have received considerable attention recently. Folic acid is recognized by folate receptors, which are overexpressed in several cancer cells; it is limited in normal cells. In this work, pterin-6-carboxylic acid is proposed as an agonist of folic acid since the pterin-6-carboxylic acid structure has a pterin moiety, the same as folic acid that is recognized by the folate receptor. Here a simple photochemical synthesis of gold nanoparticles functionalized with pterin-6-carboxylic acid is studied. These conjugates were used to cause photothermal damage of HeLa cells irradiating with a diode laser of 808 nm. Pterin-6-carboxylic acid-conjugated gold nanoparticles caused the death of the cell after near-infrared irradiation, dose-dependently. These results indicate a possible internalization of AuNPs via folate receptor-mediated endocytosis due to the recognition or interaction between the folate receptors of HeLa cells and pterin, P6CA. [ABSTRACT FROM AUTHOR]

The pulsed laser is highly used in optics and material sciences, where the high energy of the laser pulse produces an ablation effect that is applied to the obtention of nanoparticles by impacting a target material. We present a complete methodology that includes the preparation of a CdSe target and the synthesis of CdM (M = Se, O) micro and nanoparticles in water by pulsed laser ablation from the previously prepared CdSe target. The laser energy lets to control the properties of particles; we obtain four CdM micro and nanoparticles samples with four different laser energies, that is, 10.25, 20.72, 30.38, and 39.72 mJ. The best result was achieved with 30.38 mJ; at this energy, we obtain nanoparticles with Z‐average size below 100 nm, confirmed by analysis of dynamic light scattering (DLS). In the scanning electron microscopy (SEM) images of the particles obtained at 30.38 mJ, we observed polydispersity in the sample, in addition to irregularly shaped nanoparticles and particle agglomerations. The analysis of the characterization by UV–Vis, energy dispersive spectroscopy (EDS), and X‐ray photoelectron spectroscopy (XPS) suggests the presence of micro and nanoparticles of CdSe and CdO in the sample. [ABSTRACT FROM AUTHOR]

TiO2 electrochemical biosensors represent an option for biomolecules recognition associated with diseases, food or environmental contaminants, drug interactions and related topics. The relevance of TiO2 biosensors is due to the high selectivity and sensitivity that can be achieved. The development of electrochemical biosensors based on nanostructured TiO2 surfaces requires knowing the signal extracted from them and its relationship with the properties of the transducer, such as the crystalline phase, the roughness and the morphology of the TiO2 nanostructures. Using relevant literature published in the last decade, an overview of TiO2 based biosensors is here provided. First, the principal fabrication methods of nanostructured TiO2 surfaces are presented and their properties are briefly described. Secondly, the different detection techniques and representative examples of their applications are provided. Finally, the functionalization strategies with biomolecules are discussed. This work could contribute as a reference for the design of electrochemical biosensors based on nanostructured TiO2 surfaces, considering the detection technique and the experimental electrochemical conditions needed for a specific analyte. [ABSTRACT FROM AUTHOR]