Intracellular silver accumulation in Chlamydomonas reinhardtii upon exposure to carbonate coated silver nanoparticles and silver nitrate.
The intracellular silver accumulation ({Ag}(in)) upon exposure to carbonate coated silver nanoparticles (AgNP, 0.5-10 μM, average diameter 29 nm) and silver nitrate (20-500 nM) was examined in the wild type and in the cell wall free mutant of the green alga Chlamydomonas reinhardtii at pH 7.5. The {Ag}(in) was measured over time up to 1 h after a wash procedure to remove silver ions (Ag(+)) and AgNP from the algal cell surface. The {Ag}(in) increased with increasing exposure time and with increasing AgNP and AgNO(3) concentrations in the exposure media, reaching steady-state concentrations between 10(-5) and 10(-3) mol L(cell)(-1). According to estimated kinetic parameters, high Ag(+) bioconcentration factors were calculated (>10(3) L L(cell)(-1)). Higher accumulation rate constants were assessed in the cell wall free mutant, indicating a protective role of the cell wall in limiting Ag(+) uptake. The bioavailability of AgNP was calculated to be low in both strains relative to Ag(+), suggesting that AgNP internalization across the cell membrane was limited.
Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Duebendorf, Switzerland.
Flavio
F
Piccapietra
Carmen Gil
CG
Allué
Laura
L
Sigg
Renata
R
Behra
D002254:Carbonates / Q000737:chemistry*; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism*; D004781:Environmental Exposure; D007700:Kinetics; D009154:Mutation; D053758:Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry / Q000378:metabolism*; D012835:Silver Nitrate / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism*
D002254:Carbonates; D014874:Water Pollutants, Chemical; D012834:Silver; D012835:Silver Nitrate