CHEMISTRY: Packaging Proteins into Aerogels

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Science  10 Oct 2003:
Vol. 302, Issue 5643, pp. 199b
DOI: 10.1126/science.302.5643.199b

Encapsulation of proteins is desirable for their use in applications such as sensors. Many proteins have been encapsulated in sol gels, but the ultraporous nature of aerogels would provide faster response times. However, the high pressures and temperatures of aerogel processing have limited aerogel encapsulation to enzymes such as lipases that readily withstand extreme conditions. Wallace et al. show how the introduction of colloidal gold allows cytochrome c (cyt c) to be assembled into an aerogel and retain activity. Without colloidal gold, supercritical processing of cyt c-silica gels destroys even the metal-porphyrin coordination. Incubation of cyt c with colloidal gold appears to nucleate a multilayer protein shell. Transmission electron microscopy suggests that the outer layer of protein is damaged in the aerogel but that the majority of the cyt c molecules are preserved intact; absorption of gas-phase NO leads to characteristic changes in the intensity of the Soret band at 410 nm. The superstructure formed protects the undamaged proteins even against strong denaturants such as guanidinium hydrochloride. — PDS

Nano Lett. 10.1021/nl03646b (2003).

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