A facile one-pot synthesis of water-soluble CQDs for the evaluation of their anti-amyloidogenic propensity

Abstract

Herein, we present a one-pot microwave-assisted facile synthesis of highly water-soluble CQDs and explore their inhibitory effect towards amyloid fibrillation or their anti-amyloidogenic properties using hen egg-white lysozyme for fibrillation in acidic and neutral pH and explore their potential application as a drug against protein linked neurodegenerative diseases. The average 7 nm sized CQDs prepared using direct carbonization of folic acid and bis-acryl amide under microwave showed long shelf life due to high negative surface charge, which also makes them highly soluble in water, resulting in high photo-stability (pH), high quantum yield (QY), without the need for a surface passivation step after synthesis, thus making the process less cumbersome than the contemporary ones. Upon exploration, the prepared CQDs demonstrated a significant inhibitory effect towards the HEWL amyloid aggregation process in both acidic and neutral pH, as it inhibits up to 60% in acidic pH and up to 50% in neutral pH conditions of the process, which were confirmed using various assays, such as ThT and ANS. Proteins, under certain destabilising conditions, have been seen to unfold and aggregate to form ordered β-sheeted fibrillar aggregates called “amyloids”. These fibrils are the main precursors for protein-linked degenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and Type II diabetes mellitus. Thus, with the anti-amyloidogenic properties of the CQD as well as their excellent intrinsic characteristics, these CQD have appeared to be good potential candidates for the treatment of protein-linked nuero degenerative diseases.