“
“Virus-like particles (VLP) are formed when viral structural proteins are produced in an heterologous expression system. Such proteins assemble into structures that are morphologically similar to native viruses but lack the viral

genome. VLP are complex structures with a wide variety of applications, ranging from basic research and vaccines to potential new uses in nanotechnology. Production of VLP is a challenging task, as both the synthesis check details and assembly of one or more recombinant proteins are required. This is the case for VLP of rotavirus (RLP), which is an RNA virus with a capsid formed by 1860 monomers of four different proteins. In addition. the production of most VLP requires the simultaneous expression and assembly of several recombinant proteins, which – for the case of RLP – needs to Occur in a single host cell. The insect cell baculovirus

expression vector system (IC-BEVS) has been shown to be a powerful and convenient system for rapidly and easily producing VLP due to several Etomoxir convenient features. including its versatility and the short time needed for construction of recombinant baculovirus. In this review, the specific case of rotavirus-like particle (RLP) production by the IC-BEVS is discussed, with emphasis on bioprocess engineering issues that exist and their solutions. Many culture strategies discussed here can be useful for the production of other VLP. (C) 2009 Elsevier B.V. All rights reserved”
“We report the machining of doubly-clamped

SiCN nanomechanical resonators as narrow as 16 nm and lengths of up to 10 mu m with a yield approaching 100%. The resonators were actuated using a piezoelectric disk, and their resonant response was detected using optical interferometry. Resonators with widths ranging from 16 to 375 nm and lengths from 10 to 50 mu m were analyzed at room temperature at pressures ranging from 10 to selleck kinase inhibitor 50 mTorr. Resonant frequencies in the 4-15 MHz range and quality factors in the 1000-7000 range were measured. We observed a significant decrease in resonant frequency with decreasing resonator width. The results of finite element analysis (FEA) show that this width dependence is mainly due to the resonators vibrating in the horizontal rather than vertical direction. At widths below 50 nm the comparison of experimental and FEA data suggest a gradual tensile stress reduction in the resonators as their width is reduced. Material softening is the most likely cause of this stress reduction. Additionally, the resonant behavior of 16, 55, and 375 nm wide devices was studied as a function of ambient pressure in the 10(-5)-10 Torr range. Resonance quality becomes dominated by gas damping effects at pressures above a threshold determined by the intrinsic Q-factor of the resonator. The intrinsic Q-factor tended to decrease with decreasing resonator width but was independent of length or resonant frequency.