Chitosan functionalized iron oxide nanocomposites as a novel carbonic anhydrase nano-inhibitor

Abstract This study evaluates the interaction between different molecular weight chitosan functionalized iron oxide nanoparticles (INPs) and carbonic anhydrase II (CAII) as a new approach for the inhibition of CAII. INPs functionalized with different molecular weight chitosan (HC-INPs, MC-INPs, LC-INPs). The characterizations of the synthesized nanocomposites were performed using TEM, XRD, Zeta potential, FTIR, and VSM. The interaction of nanocomposites with CAII was also assessed. The average diameters of prepared nano-formulations were approximate, 4 nm, 11.5 nm, and 20 nm for HC-INPs, MC-INPs, and LC-INPs respectively. Zeta potential values were 39.2 ± 3.9 mV, 36.7 ± 4.1 mV, and 15.5 ± 4.6 mV for HC-INPs, MC-INPs, and LC-INPs respectively. Fluorescence quenching assays and Enzyme Kinetics activity results revealed that the CAII-nanocomposites interaction led to CAII conformational changes that rendered the enzyme inactive. Interestingly, we found that the surface property of nano-inhibitors plays a vital role in their inhibition ability. Whereas HC-INPs have the most potent inhibitory effect with Ki (ng/ml) = 58.388 (ng/ml). While MC-INPs and LC-INPs have Ki=390.87 (ng/ml) and 1213.00 (ng/ml), respectively. The prepared chitosan functionalized iron oxide nanoparticles (especially HC-INPs) are considered a novel nano-inhibitor for CAII which pave the way for using HC-INPs to target disorders related to CAII overexpression.