Supramolecular structures constructed by the self-assembly of biomolecules are of special interest in a range of areas, including bio nanotechnology and nanomedicine. The nucleobase guanosine and its derivatives form tetramers linked by Hoogsteen-type hydrogen bonds, in presence of cation as Na+ and K+. These tetramers, called G-quartets stack on top of one another to form elongated structures denominated G-quadruplex. These structures resemble cylinder fibers with well-defined diameter of internal cavity. From the biological point of view many studies have been performed to understand the role of G-quadruplex within the DNA sequence. In the biotechnological field, because G-quadruplex is able to form hydrogels, this material is receiving considerable attention with their potential applications in drug delivery, biosensor and tissue engineering. Because they are form from the self-association of natural molecules they are biodegradable and biocompatible with potential for in vivo applications. If compared with traditional carrier systems, hydrogels find many advantages because of their high viscosity and low fluidity, the bioactive compound can have longer contact time with the tissue, with low diffusion, minimizing possible side effects. In this project, we intend to develop a methodology for the incorporation and release of biomolecules in G-quadruplex hydrogels, in particular photosensitizers for possible applications in photodynamic therapy (PDT). We intend to explore the properties of methylene blue incorporation and retention in G-quadruplex hydrogels in function of the characteristics of the precursor gel, temperature, pH and ionic strength, investigating the properties and applicability of a new biomaterial.
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