Modulating surface functional groups in carbon dots for enhanced inhibition of β-amyloid aggregation

Gaining a profound understanding of carbon dots (CDs) structure and their potential to inhibit beta-amyloid (A beta) aggregation holds significant importance in the quest for Alzheimer's disease (AD) prevention and treatment. Herein, CDs with varying structures were synthesized by adjusting the molar ratio of citric acid (CA) and ethylenediamine (EDA). Transmission electron microscopy (TEM) was used to characterize their size and morphology. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were applied to study their structure. Optical properties were analyzed through Ultraviolet (UV) spectroscopy absorption and fluorescence spectroscopy. The inhibitory effect of CDs on A beta 1-42 aggregation was explored using circular dichroism and atomic force microscopy (AFM). The results highlighted the substantial influence of the CA to EDA molar ratio on the surface structure of CDs, subsequently impacting their optical properties and efficacy in inhibiting A beta 1-42 aggregation. With increasing EDA content, CDs exhibited a rise in the number of amino functional groups while experiencing a reduction in carboxyl groups. CDs possessing more amino functional groups effectively induced alterations in the initial conformation of A beta 1-42, leading to a significant inhibition of A beta 1-42 aggregation.