title: Fungal surface protein mediated one-pot synthesis of stable and hemocompatible gold nanoparticles.
abstract: Despite their large secretome and wide applications in bioprocesses, fungi remain underexplored in metal nanoparticles (MNP) biosynthesis. Previous studies have shown that cell surface proteins of Rhizopus oryzae play a crucial role in biomineralization of Au(III) to produce gold nanoparticles (AuNPs). Therefore, it is hypothesized that purified cell surface protein may produce in vitro AuNPs with narrow size distribution for biomedical and biocatalytic applications. However, different protein extraction methods might affect protein stability and the AuNP biosynthesis process. Herein, we have explored the extraction of cell surface proteins from R. oryzae using common detergents and reducing agent (sodium dodecyl sulfate (SDS) Triton X-100, and 1,4-dithiothreitol (DTT)) and their effect on the size and shape of the biosynthetic AuNPs. The surface proteins extracted with reducing agent (DTT) and non-ionic detergent (Triton X-100) produce spherical AuNPs with a mean particle size of 16±7nm, and 19±4nm, respectively, while the AuNPs produced by the surface protein extracted by ionic detergent (SDS) are flower-like AuNPs with broader size distribution of 43±19nm. This synthetic approach does not require use of any harsh chemicals, multistep preparation and separation process, favouring environmental sustainability. The biosynthetic AuNPs thus formed, are stable in different physiological buffers and hemocompatible, making them suitable for biomedical applications.
authors.affiliation: School of Biotechnology, Dublin City University, Dublin 9, Ireland.
authors.forename: Michael
authors.initials: M
authors.lastname: Kitching
authors.affiliation: Biological Materials Laboratory, CSIR-Central Leather Research Institute, Chennai, 600020, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi,  110001, India.
authors.forename: Priyadarshani
authors.initials: P
authors.lastname: Choudhary
authors.affiliation: School of Physics, Dublin City University, Collins Avenue, Dublin 9, Ireland.
authors.forename: Saikumar
authors.initials: S
authors.lastname: Inguva
authors.affiliation: Materials and Surface Science Institute, University of Limerick, National Technological Park, Limerick, Ireland.
authors.forename: Yina
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Nanotechnology Innovation Centre of Kansas State, Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66502, USA.
authors.forename: Meghana
authors.initials: M
authors.lastname: Ramani
authors.affiliation: Biological Materials Laboratory, CSIR-Central Leather Research Institute, Chennai, 600020, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi,  110001, India. Electronic address: sujoy@clri.res.in.
authors.forename: Sujoy K
authors.initials: SK
authors.lastname: Das
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459, Singapore; Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore. Electronic address: emarsili@ntu.edu.sg.
authors.forename: Enrico
authors.initials: E
authors.lastname: Marsili
mesh_terms: D001709:Biotechnology; D005656:Fungal Proteins / Q000378:metabolism*; D006046:Gold / Q000737:chemistry*; D055772:Green Chemistry Technology; D006461:Hemolysis; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008565:Membrane Proteins / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D010084:Oxidation-Reduction; D012233:Rhizopus / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D008565:Membrane Proteins; D006046:Gold
keywords: Gold nanoparticles; Nanobiosynthesis; Protein extraction