A major challenge in understanding nanoplastic toxicity (or nanoparticles in general) lies in establishing the causal relationships between its physical properties and biological impact. This difficulty can be attributed to surface alterations that follow the formation of a biological complex around the nanoplastic, as exemplified by protein coronae. The protein corona is known to be responsible for the biological response elicited, although its own structure and attributes remain unknown. We approach this knowledge gap by independently studying the structure of soft and hard coronae using neutron scattering techniques. We investigated the formation and the structure of corona proteins (human serum albumin and lysozyme) and the resulting protein corona complexes with polystyrene nanoplastics of different sizes (20 and 200 nm) and charges. Soft corona complexes (regardless of protein type) adopted a structure where the nanoplastics were surrounded by a loose protein layer (∼2–3 protein molecules thick). Hard corona complexes formed fractal-like aggregates, and the morphology of which is known to be harmful to cellular membranes. In most cases, hard-corona coated nanoplastics also formed fractal-like aggregates in solution. Nanoplastic size affected the structures of both the protein corona and the intrinsic protein: more significant conformational change was observed in the hard corona proteins around smaller nanoparticles compared to larger ones, as the self-association forces holding the nanoplastic/protein complex together were stronger. This also implies that protein-dependent biochemical processes are more likely to be disrupted by smaller polystyrene nanoplastics, rather than larger ones.

中文翻译：

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聚苯乙烯纳米塑料周围软硬蛋白冠的结构-粒度和蛋白质类型。

理解纳米塑料毒性（或一般的纳米粒子）的一个主要挑战在于建立其物理特性和生物影响之间的因果关系。这种困难可归因于在纳米塑料周围形成生物复合物后的表面变化，例如蛋白质冠状。已知蛋白质电晕负责引发的生物反应，尽管其自身的结构和属性仍然未知。我们通过使用中子散射技术独立研究软日冕和硬日冕的结构来解决这一知识差距。我们研究了电晕蛋白（人血清白蛋白和溶菌酶）的形成和结构，以及由此产生的蛋白质电晕复合物与不同尺寸（20 和 200 nm）和电荷的聚苯乙烯纳米塑料。软电晕复合物（无论蛋白质类型如何）采用一种结构，其中纳米塑料被松散的蛋白质层（约 2-3 个蛋白质分子厚）包围。硬电晕复合物形成分形状聚集体，其形态已知对细胞膜有害。在大多数情况下，硬电晕涂层纳米塑料也在溶液中形成分形状聚集体。纳米塑料的大小影响了蛋白质电晕和内在蛋白质的结构：与较大的纳米颗粒相比，在较小纳米颗粒周围的硬电晕蛋白质中观察到更显着的构象变化，因为将纳米塑料/蛋白质复合物结合在一起的自缔合力更强。这也意味着依赖蛋白质的生化过程更有可能被较小的聚苯乙烯纳米塑料破坏，