Nanoestructuras de oro modificadas para aplicaciones biológicas

Resumen

This thesis has been focused on the functionalization of nanostructures for their use in drug delivery projects or the development of sensors of nucleic acids. In this regard, several linkers for the functionalization of nanostructures have been prepared, which have been designed to contain different reactive moieties, such as dithiolane or maleimide. Moreover, these derivatives have been prepared with stimuli-responsive bonds to ease the release of the drugs or oligonucleotides. Also, a new protocol to quantify the loading of oligonucleotides on gold nanoparticles was developed. In this case, after some manipulations of the samples, the oligonucleotides were quantified from the supernatant by absorbance spectrum using a corresponding calibration curve. In this line, the procedure to modify AuNPs has been optimized, achieving excellent results in a very short time (1 hour). With modified AuNPs, some applications have been developed, such as a novel catalytic complex and ligand for CuAAC fluorogenic reactions. Using the catalytic complex approach the best results were obtained with a PolyG of 12 nts. On the other hand, using the nanoparticles as ligand, the best results were obtained with the PolyT of 12 nts. Also, nanostructures as gold and albumin-based nanoparticles have been functionalized with different drugs (SN38, AZD8055 or Doxorubicin) and used for the treatment of cancer with excellent results. Modified gold nanoparticles have also been used as biosensors of nucleic acids involved in diseases, such as cancer or SARS-CoV-2. For the detection of cancer, a nanostructure containing a molecular beacon-like oligonucleotide with several modifications has been used to develop a sensor for Uveal melanoma. In this case, a double stimuli system has been implemented to control better the specificity and intensity of the system. For SARS-CoV-2 detection, two approaches have been developed. One approach is based on a molecular beacon-like structure containing a cholesterol modification, which in the presence of the target sequence, the nanoparticles aggregate. The other approach exploits a CRISPR/CAS-based Colorimetric nucleic Acid Detection (CASCADE) system that, in the presence of the target sequence, Cas13 nuclease activity was activated, leading to the aggregation of the nanoparticles.