title: In vivo biodegradation of colloidal quantum dots by a freshwater invertebrate, Daphnia magna.
abstract: Impacts of planktonic invertebrate, Daphnia magna, on the speciation of colloidal quantum dots (QD) were investigated using fluorescence spectromicroscopic technique. Well-dispersed (GA/TOPO)QD were prepared by forming a supramolecular assembly of hydrophobic (TOPO)QD with biomacromolecules (i.e., Gum Arabic, GA). Biological degradation of this nanomaterial was monitored by fluorescence spectromicroscopic methods. Our study confirmed the major uptake pathway of manufactured nanomaterials and in vivo biodegradation processes in a well-known toxicity test organism, D. magna. In addition, we also found that D. magna can induce significant deterioration of aquatic media by releasing fragments of partially degraded QD colloids. These biological processes may significantly change the predicted toxicities of nanomaterials in aquatic environments. Thus, we propose that the impacts of aquatic living organisms on the environmental fate of manufactured nanomaterials (MNs) should be carefully taken into account when assessing the risk of MNs to the environment and human health.
authors.affiliation: Department of Chemistry, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Dongwook
authors.initials: D
authors.lastname: Kwon
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Chansik
authors.initials: C
authors.lastname: Park
authors.forename: Jaehong
authors.initials: J
authors.lastname: Park
authors.forename: Kyungho
authors.initials: K
authors.lastname: Choi
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Yoon
mesh_terms: D000818:Animals; D003102:Colloids / Q000737:chemistry / Q000378:metabolism*; D003621:Daphnia / Q000378:metabolism*; D045663:Quantum Dots; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003102:Colloids; D014874:Water Pollutants, Chemical; D014867:Water