(596b) Benign, 3D Encapsulation of Living Cells with Lys-Sil Nanoparticles

Fan, W., University of Massachusetts Amherst
Atchison, N., University of Minnesota
Kidder, L. S., University of Minnesota
Maynard, K., University of Minnesota
Papas, K. K., University of Minnesota

Benign encapsulation of living cells within stable, permselective materials holds exciting prospects for

implantable autonomous therapeutics, but is challenged by the demand by such applications for materials bearing an optimal combination of microstructure, stability, and functionality. The ideal capsule would simultaneously protect the cell from immunological attack, efficiently transport nutrients, and rapidly release therapeutic cell metabolites. Recently, we have developed a benign and controllable method for synthesizing stable silica nanoparticles (Lys-Sil) from 10 to 50 nm, and their in situ and ex situ ordering into colloidal crystal arrays and thin films1. Encapsulating living cells within nanoparticle films of controllable thickness (i.e., tens of nanometers) will translate to higher flux of chemical species2. In addition, the porosity of such ordered nanoparticle films, imparted by the interstitial spacing between particles, can be tuned through particle size control and functionalization to dimensions commensurate with the passage of nutrients and rejection of immunological triggers. We highlight the tunable surface properties (surface charge and functional group) of Lys-Sil nanoparticles, and demonstrate the incorporation of fluorescent dye. Laser scanning confocal microscopy (LSCM) and electron microscopy reveal that under certain conditions a beta cell surrogate cell line, INS-1, was successfully encapsulated by positively charged silica nanoparticles with controllable film thickness and porosity. The details of the encapsulation process and toxicity of silica nanoparticles on living cells will be discussed.

1. Snyder, M. A.; Lee, J. A.; Davis, T. M.; Scriven, L. E.; Tsapatsis, M. Langmuir, 2007, 23, 9924.

2. Snyder, M. A.; Demirgöz, D.; Kokkoli, E., Tsapatsis, M. Microporous Mesoporous Mater. 2009, 118, 387.