Nitrogen doped carbon quantum dots: a multifaceted carbon nanomaterial that interferes in an amyloid-forming trajectory

Abstract

Carbon quantum dots (CQDs) are a versatile class of carbon-based nanomaterial frameworks that have previously been used as a diagnostic device, in sensing for environmental applications, in bioimaging, and for drug delivery systems. Their versatility stems from their ability to be chemically tailored via functionalization to optimize properties for specific applications. In this study, we have synthesized lactic acid-derived nitrogen doped carbon quantum dots (LAdN-CQDs) and examined their ability to intervene in the conversion of soluble, monomeric hen egg-white lysozyme (HEWL) into mature fibrils. Our data indicate that LAdN-CQDs inhibit HEWL fibril formation in a dose-dependent manner (achieving up to 50% inhibition at 2.5 mg mL⁻¹). Furthermore, in a neuroblastoma-derived cell line, LAdN-CQDs were found not to disrupt mitochondrial membrane potential or trigger apoptosis at the same concentration range, suggesting that they are biocompatible. LAdN-CQDs effectively neutralized reactive oxygen species (ROS), with a 50% decrease in ROS levels at just 100 μg mL⁻¹ when challenged with an established free radical generator and protected the cell line from rotenone-induced apoptosis. The ability of LadN-CQDs to inhibit the soluble-to-toxic transformation of HEWL, the tolerance of SHSY-5Y cells to LAdN-CQDs, and their ability to restitute cells from rotenone-induced apoptosis, combined with the biocompatibility findings, suggest that LAdN-CQDs are potentially neuroprotective. The findings indicate that LAdN-CQDs represent a versatile, carbon-based, sustainable nanoplatform that bridges nanotechnology and neuroprotection, promoting the development of green chemistry-based healthcare solutions.