Energy transfer studies between peptides and lanthanides with biosensor applications

Author(s)

Lais Roncalho de Lima

• Document type: Doctoral Thesis
• Press: Araraquara. 2018-06-20.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Química. Araraquara
• Defense date: 2018-05-15
• Advisor: Sidney José Lima Ribeiro

Abstract

In this work the antimicrobial peptide hylina - a1 was synthetized and strategically modified with add one tryptophan residue (W) in position 6 of the chain, aiming the interaction study and energy transfer that aromatic amino acid with YVO4:Ln3+ luminescent nanoparticles. The analyses were realized in solution and in solid state from self-assembled films by Layer-by-Layer (LbL) technique, using silk fibroin (SF) as immobilization matrix for the nanoparticles (NPs). Results show the energy transfer mechanism occurs only in the films containing the Hyl-K0-W6 peptide in touch with the YVO4:Eu3+ NPs. Because this peptide has activity against strains of Methicillin Resistant Staphylococcus aureus (MRSA), spectroscopic studies were realized using the PBP2a protein, it is present at cytoplasmic membrane of the bacterium and it is responsible for resistance against β-lactam antibiotics. Results confirmed interaction of PBP2a protein only with the Hyl-K0-W6 peptide in conjunction of the YVO4:Eu3+ NPs. Aiming application that film as a biosensor, electrochemistry measurements were realized, which the results showed clearly greater interaction when PBP2a was adsorbed on SF/Hyl-K0-W6+NPs films. From these dates, the system was applied as MRSA biosensor prototype, through detection a antigenic extract containing the real bacterium. (AU)

• FAPESP's process: 14/05948-5 - Energy transfer peptide-lanthanides: optimization of antenna effect and application in biosensors
• Grantee: Lais Roncalho de Lima
• Support Opportunities: Scholarships in Brazil - Doctorate