Surface defect rich ZnO quantum dots as antioxidants inhibiting α-amylase and α-glucosidase: a potential anti-diabetic nanomedicine

Abstract

Preventing chronic hyperglycaemia and associated oxidative stress is utmost important for the treatment and management of Type 2 Diabetes Mellitus (T2DM). Here we report the role of different size surface defect rich ZnO quantum dots (D-QDs) for inhibiting metabolic enzymes and scavenging free radicals, which plays a key role in reducing hyperglycaemia and oxidative stress. Quantitative analysis of radical scavenging and metabolic enzyme inhibition activity of D-QDs demonstrates a size dependent behaviour, where D-QDs with a smaller diameter shows superior activity compared to larger size D-QDs. Considering the size dependence in surface defect formation, the increased surface defect density in smaller size D-QDs can be considered as the reason behind this enhancement. Detailed studies establishing the underlying mechanism behind potent free radical scavenging and enzyme inhibition provides an intense scientific rationale for considering D-QDs to design safe and effective nanomedicine for T2DM.

Synthesis, Characterization, Luminescent and Nonlinear Optical Responses of Nanosized ZnO

“…The fast rate of the process prevents further NPs growth. It resulted in the formation of the solids containing defective ZnO NPs, which are similar to the ones reported in [ 34 , 35 ]. In contrast to the small ZnO NPs, the solids with HD contains 50 nm ZnO covered with HD and the rest of the hydrolysis products.…”

Platanus orientalis Leaf Mediated Rapid Synthesis of Catalytic Gold and Silver Nanoparticles

“…It is important to note that the activity of nanomaterials primarily depend on their size and shape [1]. In spite of availability of diverse physico-chemical methods like microwave assisted, laser ablation, sol-gel, that involve hazardous chemicals, toxic solvents, high temperature and high pressure to fabricate monodispersed nanoparticles, biological routes are preferred and are widely explored in the recent past [2][3][4]. Hence, there is a continuous need to develop novel eco-friendly, non-hazardous, safe and efficient biological routes for synthesis of stable nanoparticles ideal for well defined physicochemical and therapeutic applications [5,6].…”

ZnO Quantum Dots: Broad Spectrum Microbicidal Agent Against Multidrug Resistant Pathogens E. coli and C. albicans

“…Moreover, the quantum confinement of ZnO QDs creates surface defects on ZnO QDs and produces large number of electron donor or acceptor active sites, which react with oxygen and hydroxyl ions (in aqueous suspension) to produce highly reactive superoxide and hydroxyl radicals. These highly reactive free radicals contribute to enhanced ROS generation and result in peroxidation of lipids, nucleic acid and proteins, disruption of cell membrane and leakage of cytoplasmic content, thus leading to cell death (Asok et al, 2015;Gold et al, 2018;Radhakrishnan et al, 2018a;Tiwari et al, 2018). In addition, the small size of ZnO QDs also provide larger surface area for their higher interaction with microbial cells.…”

“…Furthermore, the surface defects of ZnO QDs might also increase the density of positive surface charge as particle size decreases, which might increase interaction with microbial cells (possessing negative charge). This can lead to higher agglomeration of ZnO QDs on the surface of microbes leading to altered metabolic activity and increased antimicrobial activity (Asok et al, 2015). Thus, small size of ZnO QDs might exert excellent antimicrobial activity through multiple mechanisms.…”