In vitro biocompatibility of nanoscale zerovalent iron particles (NZVI) synthesized using tea polyphenols

A green protocol was used for the rapid generation of nanoscale zerovalent iron (NZVI) particles using tea polyphenols. The NZVI particles were subsequently examined for in vitro biocompatibility using the human keratinocyte cell (HaCaT) line as a representative skin exposure model. The cells were exposed to NZVI for time periods of 24 and 48 h. Biocompatibility was assessed using the methyl tetrazolium, or MTS, (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)) and lactate dehydrogenase (LDH) assays to determine in vitro cytotoxicity. The evaluation of mitochondrial function (MTS) and membrane integrity (LDH) in human keratinocytes showed that these green synthesized NZVI particles were nontoxic in the human keratinocytes exposed when compared with control samples synthesized using a borohydride protocol. In fact, in most cases, these green nanoparticles induced a prolific response in the cellular function even at the highest concentration (100 mu g ml(-1)).