ORCID Profile
0000-0001-9753-4217
Current Organisations
The University of Auckland
,
Københavns Universitet
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Publisher: American Chemical Society (ACS)
Date: 03-2019
DOI: 10.1021/ACS.BIOCONJCHEM.9B00015
Abstract: Upon contact with biological fluids, the surface of nanoparticles is surrounded by many types of proteins, forming a so-called "protein corona". The physicochemical properties of the nanoparticle/corona complex depend predominantly on the nature of the protein corona. An understanding of the structure of the corona and the resulting complex provides insight into the structure-activity relationship. Here, we structurally evaluate the soft and hard components of the protein corona, formed from polystyrene (PS) nanoplastics and human serum albumin (HSA). Using circular dichroism spectroscopy to elucidate the structure of HSA within the complex, we establish the effect of nanoparticle size and pH on the nature of the protein corona formed- whether hard or soft. Despite the weak interaction between PS and the HSA corona, small angle neutron scattering revealed the formation of a complex structure that enhanced the intermolecular interactions between HSA proteins, PS particles, and the HS/PSA complexes. Fractal formation occurred under conditions where the interaction between PS and HSA was strong, and increasing HSA concentrations suppressed the degree of aggregation. The size of the nanoparticles directly influenced the nature of the protein corona, with larger particles favoring the formation of a soft corona, due to the decreased PS-HSA attraction.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SM00932A
Abstract: Explaining antimicrobial battacin lipopeptides by investigating the solution structure – the propensity to aggregate may have a role in a declined antimicrobial activity.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0SM01071E
Abstract: Increased water solubility and long-range intermolecular ordering have been introduced into the fluorescent organic molecule thiophene-diketopyrrolopyrrole via its conjugation to the octapeptide HEFISTAH, derived from a protein–protein β-interface.
Publisher: American Vacuum Society
Date: 09-2020
DOI: 10.1116/6.0000404
Abstract: 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 rotein 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.
Publisher: Elsevier BV
Date: 02-2021
Publisher: American Vacuum Society
Date: 07-2021
DOI: 10.1116/6.0001124
Abstract: Plastic waste is ubiquitously spread across the world and its smaller analogs-microplastics and nanoplastics-raise particular health concerns. While biological impacts of microplastics and nanoplastics have been actively studied, the chemical and biological bases for the adverse effects are sought after. This work explores contributory factors by combining results from in vitro and model mammalian membrane experimentation to assess the outcome of cell/nanoplastic interactions in molecular detail, inspecting the in idual contribution of nanoplastics and different types of protein coronae. The in vitro study showed mild cytotoxicity and cellular uptake of polystyrene (PS) nanoplastics, with no clear trend based on nanoplastic size (20 and 200 nm) or surface charge. In contrast, a nanoplastic size-dependency on bilayer disruption was observed in the model system. This suggests that membrane disruption resulting from direct interaction with PS nanoplastics has little correlation with cytotoxicity. Furthermore, the level of bilayer disruption was found to be limited to the hydrophilic headgroup, indicating that transmembrane diffusion was an unlikely pathway for cellular uptake-endocytosis is the viable mechanism. In rare cases, small PS nanoplastics (20 nm) were found in the vicinity of chromosomes without a nuclear membrane surrounding them however, this was not observed for larger PS nanoplastics (200 nm). We hypothesize that the nanoplastics can interact with chromosomes prior to nuclear membrane formation. Overall, precoating PS particles with protein coronae reduced the cytotoxicity, irrespective of the corona type. When comparing the two types, the extent of reduction was more apparent with soft than hard corona.
No related grants have been discovered for Shinji Kihara.