Zinc Oxide and Polyamine Nanoparticles: Interaction Mechanism study

MEDINA, A. V.; LEDESMA, ANA E.; MELLANO, M. F.; HUGO A. PÉREZ

Córdoba

Congreso; LI Reunión Anual de la Sociedad Argentina de Biofísica; 2023

Sociedad Argentina de Biofísica

Abioticstress in plants is considered a major problem in agriculture. Stress typesinclude drought, salinity, alkalinity, and temperature, among others, whichminimise the growth and productivity of crops. During their life cycle, plantsare exposed to several types of abiotic stresses and develop defence mechanismsto cope with them using different physiological pathways. In recent years, theuse of exogenous compounds such as polyamines (PAs) and nanoparticles (NPs) hasgrown to counteract different types of abiotic stress and promote crop growth.However, no experimental works on the interaction of these compounds has beenreported to date. Therefore, this work proposes to study the interaction ofplant polyamines, such as putrescine (PUT), with zinc oxide nanoparticles(ZnO-NPs), both of which are used in foliar form in plants. To conduct thisstudy, the fluorescence of ZnO-NPs (lexc = 370 nm) as a function of the PUT concentration wasused. The decrease in the fluorescence spectra of ZnO-NPs due to the increasein PUT was adjusted using the Stern– Volmer equation, obtaining a value of » 2000 M-1 at 25°C. The increase intemperature decreases the value of the KSV constant, suggesting thatthe quenching mechanism is stationary. Furthermore, it was determined that thethermodynamic parameters DSand DH are positive, indicating that the formation of theZnO-NPs-PUT complex is mediated by hydrophobic interactions. On the other hand,a slight bathochromic shift of the maximum emission peak of ZnO-NPs wasobserved because of the presence of PUT, which is associated with an increasein the size of the nanoparticle. The last result is in agreement with theanalysis obtained by dynamic light scattering (DLS), where PUT increases thesize of the ZnO-NPs. These results demonstrate the adsorption of polyamine onnanoparticles, which will serve as a basis for future experimental strategies.