Recetores Sintéticos Multivalentes para o Reconhecimento, Transporte e Entrega Controlada de Ácidos Nucleicos

The specific objective of this project is to develop novel stimuli-responsive nonviral vectors for the recognition and efficient delivery of nucleic acids (NAs). In contrast to the current leading nonviral vectors based on four-component lipid nanoparticles (LNPs), the approach proposed in this project aims to explore one-component vectors due to their higher potential for rational optimization based on structure-activity relationships. In fact, in addition to the advantages of nonviral vectors identified in the previous section, the unlimited synthetic possibilities of synthetic vectors are likely to represent their main advantage. Calixarenes constitute the third generation of supramolecular receptors, being described as macrocycles with (almost) unlimited possibilities, owing to their tunable scaffolds, controllable conformations, and facile modifications. They have been demonstrated to be excellent scaffolds for the preparation of biocompatible multivalent supramolecular receptors for biomedical and biological applications, which include the design and synthesis of promising nonviral vectors for the recognition and transfection of NAs. However, despite their potential, stimuli-responsive calixarene based vectors for controlled delivery of NAs remain unexplored. Very recently, our group introduced novel photoresponsive anionic calixarenes for the recognition and controlled delivery of polycationic peptides across model lipid membranes and into living cells (JACS, 2023, 145, 13126). These relatively simple and synthetically accessible receptors were found to be very potent multivalent binders, being able to recognize and delivery their targets at nM concentrations. Based on these preliminary results and encouraged by the enormous potential of multivalent calixarene-based NAs receptors, we plan to explore the calixarene scaffold to design, synthesize and optimize unprecedent stimuli-responsive nonviral vectors. Our approach will bring together, within the same molecular platform, the advantageous multivalent properties of polymeric materials with those of monodisperse, easily synthesized low molecular weight amphiphiles. We will focus on positively charged calixarene receptors that, in addition to their multivalent binding properties, will be equipped with stimuli-responsive functional units to prepare advanced nonviral vectors with light-, pH- and redox-responsive vectors. Being generally accepted that target delivery and endosomal escape remain among the most important challenges for NAs delivery,4 the proposed molecular design comprises the incorporation of pH-responsive units to address the problem of endosomal escape with light and/or redox responsive functional groups for targeted delivery. Our multidisciplinary team comprising experts in organic, supramolecular, colloid, and biological chemistry that will work in synchrony to identify structure-activity relationships, making efforts to stablish molecular design principles that will enable the rational discovery and development of potent synthetic NAs delivery systems, aiming at sustainable and up-scalable processes.