In Vitro and In Vivo Biocompatibility of Mannosylated Polystyrene Nanoparticles

Bioactive nanoparticles consisting of a polystyrene (PS) core with polyethylene glycol (PEG) tethered mannose (M) (PS-PEG-M) have potential as alternatives to antibiotics for the control of bacterial infections. Clinical use of nanoparticles necessitates contact with host tissues, either by inhalation, oral ingestion, or exposure to the eyes and skin. In vitro and in vivo exposure sensitivity studies were conducted to investigate cellular and tissue-level responses for each of these routes of exposure. MTS, Trypan blue, and Live/Dead assays were conducted to determine the response of human lung, colon, and dermal fibroblasts and rat lung macrophages to nanoparticle exposure over a range of concentrations. Ocular and skin sensitivity studies were conducted with New Zealand albino rabbits, and oral ingestion and inhalation studies were conducted with Sprague Dawley rats using approved protocols. PS-PEG-M nanoparticles did not exhibit consistent significant levels of toxicity towards human lung and dermal fibroblasts and rat lung macrophages. Very low, but significant levels of toxicity towards human colon fibroblasts were observed. The ocular studies revealed no signs of discomfort or acute inflammation. The dermal studies showed no signs of edema or erythema. No inflammatory response was evident in blood or tissue samples of the lungs, gastrointestinal tract, liver, kidney, and spleen that were collected in the inhalation and oral ingestion studies. The results from these studies provide evidence that these nanoparticles may be safe for use as antibacterial agents.