Self-assembling protein nanocapsules can be engineered for various bionanotechnology applications.  Using the dodecahedral scaffold of the E2 subunit from pyruvate dehydrogenase, we introduced non-native surface cysteines for site-directed functionalization.  The modified nanoparticle's structural, assembly, and thermostability properties are comparable to the wild-type scaffold (E2-WT), even after attaching polyethylene glycol (PEG).  Cellular uptake properties of the PEGylated particles were studied, and reduced uptake by breast cancer and phagocytic cell lines was observed, relative to E2-WT.  Complement activation, an innate immune mechanism for recognizing and clearing pathogenic material, was also studied in vitro to determine the complement response toward the wild-type and modified nanocapsules by measuring C4 consumption and C5a release.  Evidence suggests that conjugation of PEG to these particles moderately increases the complement response, relative to E2-WT.  Our results demonstrate that PEGylation of the E2 protein nanocapsules can modulate cellular uptake and induce complement responses.

Cellular and immunological responses toward a polymer functionalized self-assembling protein nanocapsule

243rd National Meeting (2012)

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