Effect of glutathione on in vivo biodistribution and clearance of surface-modified small Pd nanosheets

Plasmonic Pd nanosheets have been emerging as promising materials for application in near-infrared （NIR） photothermal therapy （PTT） of cancer. However, animal in mice studies indicated that the original synthesized poly（vinylpyrrolidone） （PVP）-protected small Pd nanosheets （Pd-PVP） and some further surface-modified small Pd nanosheets such as Pd-PEG（SH） easily accumulated in reticuloendothelial system （RES） organs （liver, spleen, etc.） and were difficult to be cleared from these organs quickly. In the work, we surprisingly found that glutathione （GSH） could promote the clearance of surface-modified small Pd nanosheets （e.g. Pd-PVP, Pd-PEG（SH） and Pd-GSH） from the RES organs efficiently. The effects of GSH on the biodistribution and clearance of different surface-modified Pd nanosheets were investigated. Our results indicated that these surface-modified Pd nanosheets with or without GSH added caused no morbidity at target primary organs, and GSH can promote the clearance of different surface-modified Pd nanosheets in the order of Pd-PVP ≈ Pd-PEG（SH）〉Pd-GSH. This study suggests that glutathione could be an attractive reagent for promoting nanomaterials eliminated from the reticuloendothelial systems （RES）.