Interfacial Interactions within Amyloid Protein Corona Based on 2D MoS2 Nanosheets

Nanobio Interface Between Proteins and 2D Nanomaterials

Two-dimensional (2D) nanomaterials have significantly contributed to recent advances in material sciences and nanotechnology, owing to their layered structure. Despite their potential as multifunctional theranostic agents, the biomedical translation of these materials is limited due to a lack of knowledge and control over their interaction with complex biological systems. In a biological microenvironment, the high surface energy of nanomaterials leads to diverse interactions with biological moieties such as proteins, which play a crucial role in unique physiological processes. These interactions can alter the size, surface charge, shape, and interfacial composition of the nanomaterial, ultimately affecting its biological activity and identity. This review critically discusses the possible interactions between proteins and 2D nanomaterials, along with a wide spectrum of analytical techniques that can be used to study and characterize such interplay. A better understanding of these interactions would help circumvent potential risks and provide guidance toward the safer design of 2D nanomaterials as a platform technology for various biomedical applications.

Mechanistic Insights of TiO2 Nanoparticles with Different Surface Charges on Aβ42 Peptide Early Aggregation: An In Vitro and In Silico Study

Humans may intendedly or unintendedly be exposed to nanomaterials through food, water, and air. Upon exposure, nanomaterials can pierce the bloodstream and translocate to secondary organs, including the brain, which warrants increased concern for the potential health impacts of nanomaterials. Due to their large surface area and interaction energy, nanomaterials can adsorb surrounding proteins. The misfolding and self-aggregation of amyloid-β (Aβ) have been considered significant factors in the pathogenesis of Alzheimer's disease. We thus hypothesize that brain-targeted nanomaterials may modulate Aβ aggregation and cause related neurotoxicity. Here, we showed that TiO₂ nanoparticles (NPs) and their aminated analogue (TiO₂-NH₂ NPs) adsorb the Aβ₄₂ peptide and accelerate its early oligomerization. Molecular dynamics simulation indicated that the adsorption onto TiO₂ NPs and TiO₂-NH₂ NPs surfaces can stabilize the β-sheet-rich conformations formed by the Aβ₄₂ peptide. The binding sites between TiO₂-NH₂ NPs and the Aβ₄₂ oligomer surface were mainly concentrated in the hydrophobic core region, and the β-sheet conformation spontaneously formed by Aβ₄₂ oligomers can be better stabilized through a hydrogen bond, electrostatic attraction, and hydrophobic interaction. This study will further help in the understanding of nanomaterial-related neurotoxicities and the regulation of their applications.

Electric Field Effect on Inhibiting the Co-fibrillation of Amyloid Peptides by Modulating the Aggregation Pathway

With the revelation of the close link between Alzheimer's disease (AD) and type II diabetes (T2D) and the possible assembly of multiple amyloid peptides therein, it is critical to understand and regulate the co-fibrillation pathway between related amyloid peptides. Here, we show experimentally and theoretically that electric field (EF) inhibited hybrid amyloid fibrillation of β-amyloid peptide (Aβ) and human islet amyloid peptide (hIAPP) by modulating the hetero-aggregation pathway. Experimental results confirm that the β-sheet secondary structure of amyloid peptides would be disrupted under small static EF and accompanied by transforming fibril aggregates into amorphous particles in vitro. Molecular dynamics simulations further demonstrate that even with the transformation of the secondary structure from β-sheet to random coil, the strong interaction between Aβ and hIAPP peptides would remain largely unaffected under the small static EF, leading to the formation of amorphous nanoparticles observed in the experiments. This inhibitory effect of EF on the co-fibrillation of multiple amyloid peptides might contribute to reducing the mutual deterioration of different degenerative diseases and show great potential for the noninvasive treatment of amyloid-related diseases.