title: Protein-coated pH-responsive gold nanoparticles: Microwave-assisted synthesis and surface charge-dependent anticancer activity.
abstract: The biocompatibility and ease of functionalization of gold nanoparticles underlie significant potential in biotechnology and biomedicine. Eight different proteins were examined in the preparation of gold nanoparticles (AuNPs) in aqueous medium under microwave irradiation. Six of the proteins resulted in the formation of AuNPs. The intrinsic pH of the proteins played an important role in AuNPs with strong surface plasmon bands. The hydrodynamic size of the nanoparticles was larger than the values observed by TEM and ImageJ. The formation of a protein layer on the AuNPs accounts for this difference. The AuNPs exhibited sensitivity towards varying pH conditions, which was confirmed by determining the difference in the isoelectric points studied by using pH-dependent zeta potential titration. Cytotoxicity studies revealed anticancerous effects of the AuNPs at a certain micromolar concentration by constraining the growth of cancer cells with different efficacies due to the use of different proteins as capping agents. The positively charged AuNPs are internalized by the cells to a greater level than the negatively charged AuNPs. These AuNPs synthesized with protein coating holds promise as anticancer agents and would help in providing a new paradigm in area of nanoparticles.
authors.affiliation: Department of Nanobio Materials and Electronics (WCU), Gwangju Institute of Science & Technology (GIST), Gwangju 500-712, South Korea.
authors.forename: Dickson
authors.initials: D
authors.lastname: Joseph
authors.affiliation: Department of Nanobio Materials and Electronics (WCU), Gwangju Institute of Science & Technology (GIST), Gwangju 500-712, South Korea.
authors.forename: Nisha
authors.initials: N
authors.lastname: Tyagi
authors.affiliation: Department of Materials Science and Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 500-712, South Korea.
authors.forename: Christian
authors.initials: C
authors.lastname: Geckeler
authors.affiliation: Department of Nanobio Materials and Electronics (WCU), Gwangju Institute of Science & Technology (GIST), Gwangju 500-712, South Korea ; Department of Materials Science and Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 500-712, South Korea ; Institute of Medical System Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 500-712, South Korea.
authors.forename: Kurt
authors.initials: K
authors.lastname: E Geckeler
keywords: anticancer; cytotoxicity; gold Nanoparticles; pH; protein; zeta potential