title: Toxicity of bare and surfaced functionalized iron oxide nanoparticles towards microalgae.
abstract: This study investigates the toxicity of bare iron oxide nanoparticles (IONPs) and surface functionalization iron oxide nanoparticles (SF-IONPs) to the growth of freshwater microalgae Chlorella sp. This study is important due to the increased interest on the application of the magnetic responsive IONPs in various fields, such as biomedical, wastewater treatment, and microalgae harvesting. This study demonstrated that the toxicity of IONPs was mainly contributed by the indirect light shading effect from the suspending nanoparticles which is nanoparticles concentration-dependent, direct light shading effect caused by the attachment of IONPs on cell and the cell aggregation, and the oxidative stress from the internalization of IONPs into the cells. The results showed that the layer of poly(diallyldimethylammonium chloride) (PDDA) tended to mask the IONPs and hence eliminated oxidative stress toward the protein yield but it in turn tended to enhance the toxicity of IONPs by enabling the IONPs to attach on cell surfaces and cause cell aggregation. Therefore, the choice of the polymer that used for surface functionalize the IONPs is the key factor to determine the toxicity of the IONPs.
authors.affiliation: a School of Chemical Engineering, Universiti Sains Malaysia , Nibong Tebal , Penang , Malaysia.
authors.forename: Pey Yi
authors.initials: PY
authors.lastname: Toh
authors.affiliation: a School of Chemical Engineering, Universiti Sains Malaysia , Nibong Tebal , Penang , Malaysia.
authors.forename: Wan Yii
authors.initials: WY
authors.lastname: Tai
authors.affiliation: a School of Chemical Engineering, Universiti Sains Malaysia , Nibong Tebal , Penang , Malaysia.
authors.forename: Abdul Latif
authors.initials: AL
authors.lastname: Ahmad
authors.affiliation: a School of Chemical Engineering, Universiti Sains Malaysia , Nibong Tebal , Penang , Malaysia.|b Department of Physics , Carnegie Mellon University , Pittsburgh , PA , USA.
authors.forename: Jit Kang
authors.initials: JK
authors.lastname: Lim
authors.affiliation: a School of Chemical Engineering, Universiti Sains Malaysia , Nibong Tebal , Penang , Malaysia.
authors.forename: Derek Juinn Chieh
authors.initials: DJ
authors.lastname: Chan
mesh_terms: D002708:Chlorella / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D005290:Ferric Compounds / Q000737:chemistry / Q000633:toxicity*; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D058086:Microalgae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide
keywords: iron oxide nanoparticles; microalgae; polymer layer; toxicity