CHIRALITY TRANSFER TO NANOCRYSTALS BY PROTEINS, DESIGNED PEPTIDES, AND AMINO ACID TEMPLATES

Since the early development of nanotechnology, proteins, peptides, and amino acids have been frequently used to synthesize and stabilize metallic and ceramic nanoparticles. Also, several signaling peptides and enzymes have their activity modulated by the association with nanostructured particles and films. Recently, the discovery of giant magnetoresistance and chiral-induced spin selectivity has led to the emergence of innovative nanotechnological applications utilizing amino acids and proteins. Here, we present the synthesis of chiral gold, silver, and metal oxide nanocrystals templated by amino acids and natural and synthetic peptides, which have applications in health and technology. Chiral silver nanoparticles were obtained using the enantiomeric pairs of histidine as templates and used to modulate the enzymatic activity of proteases. Chiral gold nanoparticles produced with D- and L-cysteine were applied in a magnetoresistance device with spin filtering property. Tomato (Solanum lycopersicum) ferritin could also be efficiently used as a nanocage to produce superparamagnetic Fe₃O₄ and Co₃O₄ nanoparticles. In the case of Fe₃O₄ production, we developed an innovative method in which ferritin, present in tomato extract, when challenged by HAuCl4, converts its endogenous ferrihydrite core to chiral Fe₃O₄, with simultaneous synthesis of photodynamic active gold nanoparticles. Chiral Co₃O₄ nanoparticles could be produced using tomato apoferritin and the enantiomeric pair cysteinylhistidinylalanine (CHA). The chiral Co₃O₄ nanoparticles were used as an additive to cotton fabric, imparting virucidal properties. The enantiomeric pair of Co₃O₄ produced with D- and L-CHA exhibited magnetic chiroptical properties and was also efficiently used to construct a magnetoresistance device. These results evidence the versatility of chiral nanoparticles applications.

This work was supported by FAPESP (2017/02317-2) and CNPq (2021-313111-9). We thank the Multi-user Experimental Center of UFABC and LNNano/CNPEM.