The team synthesized custom GQDs and carried out a detailed physicochemical characterization, including their surface chemistry, charge, optical behavior and crystalline structure.
This indicates that the dots interfere with the ordered, β‑sheet–rich structures that define mature ASN aggregates, either by promoting their disassembly or by preventing further growth.
In the MSA mouse model, GQDs were delivered intranasally to facilitate access to the brain, a route that is increasingly explored for nanomedicine.
In treated animals, the team observed reduced ASN immunoreactivity in brain tissue, consistent with a lower burden of toxic protein aggregates.
By linking their physicochemical properties to effects on ASN aggregation, autophagy and cell viability, the study provides a framework for engineering graphene‑based nanomaterials as tools and potential leads for tackling protein‑aggregation disorders.
Researchers from Poznan University of Medical Sciences, Polish Academy of Sciences, Hirosaki University Graduate School of Medicine, University of Amsterdam, Florida Polytechnic University and Jagiellonian University have shown that graphene quantum dots (GQDs) can disrupt the harmful aggregation of the protein α‑synuclein (ASN), which plays a central role in Parkinson’s disease and multiple system atrophy (MSA). In these disorders, ASN assembles into stable protein clusters inside brain cells, damaging them over time; the study demonstrates that properly engineered GQDs can interfere with this clustering process and help reduce the toxic protein load.
The team synthesized custom GQDs and carried out a detailed physicochemical characterization, including their surface chemistry, charge, optical behavior and crystalline structure. This allowed them to link specific material features to biological activity, an important step for rational design of nanomaterials that interact with proteins in a controlled way. They then evaluated the GQDs in a multi‑stage experimental pipeline that covered cell‑free aggregation assays, human dermal fibroblasts, primary murine dopaminergic neurons and an in vivo MSA mouse model.
In a biochemical assay that monitors fibril formation using Thioflavin‑T fluorescence, GQDs destabilized pre‑formed ASN fibrils, leading to a marked drop in fluorescence signal. This indicates that the dots interfere with the ordered, β‑sheet–rich structures that define mature ASN aggregates, either by promoting their disassembly or by preventing further growth. In primary dopaminergic neurons, a cell type directly relevant to Parkinson’s disease, GQD treatment reduced the formation of pS129‑ASN inclusions, a pathological form of the protein, without impairing neuronal viability. Together, these findings support a direct, anti‑aggregative effect of GQDs in both simplified and cell‑based systems.
The researchers also examined safety and cellular stress responses using human dermal fibroblasts (NHDF). The GQDs showed good cytocompatibility at biologically relevant concentrations, with an IC50 of 90 µg mL−1 at 24 hours, meaning that half‑maximal loss of viability occurred only at relatively high doses. However, at higher concentrations and longer exposures, the particles induced dose‑ and time‑dependent cytotoxicity, activation of DNA damage responses and inflammatory signaling. These results highlight the importance of defining safe operating windows and refining surface properties for future biomedical use.
In the MSA mouse model, GQDs were delivered intranasally to facilitate access to the brain, a route that is increasingly explored for nanomedicine. In treated animals, the team observed reduced ASN immunoreactivity in brain tissue, consistent with a lower burden of toxic protein aggregates. The treatment also modulated autophagy, the cell’s own degradation and recycling pathway, suggesting that the particles act via a multimodal mechanism: they not only bind to fibrillar ASN but also influence the cellular machinery that clears damaged proteins.
Taken together, the work shows that the synthesized GQDs are bioactive across multiple levels of biological complexity, from cell‑free assays through neuronal cultures to an in vivo disease model. By linking their physicochemical properties to effects on ASN aggregation, autophagy and cell viability, the study provides a framework for engineering graphene‑based nanomaterials as tools and potential leads for tackling protein‑aggregation disorders. At the same time, the observed stress responses at higher doses underline that any future therapeutic development will require careful optimization of both efficacy and long‑term biocompatibility.
