原子力显微镜案例分享 | 类病毒颗粒帮助抗击丙肝病毒
丙肝病毒会导致慢性肝炎，甚至发展为癌症。针对丙肝病毒的疫苗尚未研发成功，而类病毒颗粒（Virus-Like Particle）是疫苗发开的路线之一。在这篇文献中，澳洲的研究者使用Cypher ES原子力显微镜，对四类丙肝类病毒颗粒进行了形貌表征和纳米力学测量。
扫描在缓冲液中进行。Cypher ES的封闭样品腔可以避免溶液的挥发，保持缓冲液的离子浓度、pH、以及温度恒定。类病毒颗粒的尺寸小于200nm，表面富含柔软的脂质。Cypher ES具有高分辨扫描能力以及精确的力控制，可以对类病毒颗粒进行准确、无损的表征。
Researchers used AFM techniques to measure the nanoscale structure and mechanical properties of virus-like particles. The results add to our understanding of how such particles could be used as a vaccine for the hepatitis C virus.
Although infection by the hepatitis C virus (HCV) can result in chronic liver disease, cancer, and even death, no approved vaccine for it currently exists. Noninfectious, self-assembling constructs called virus-like particles (VLPs) are promising candidates for an HCV vaccine. However, more information about their biophysical, biomechanical, and biochemical properties is needed to guide research.
The sub-200 nm size of HCV VLPs makes them difficult to characterize with traditional tools such as light microscopy and X rays. Therefore, a team of researchers at RMIT University and other Australian institutes demonstrated the power of AFM to evaluate biomolecules such as VLPs.
Working with VLPs that represented four common HCV genotypes, they performed in-situ morphology imaging and nanomechanical measurements on single particles. The images revealed fine structural features such as ordered core packing and indicated significant variation in particle size. In addition, the nanomechanical measurements revealed particles had a substantial range of elastic modulus.
By improving our fundamental understanding of these nanoscale particles, the results could advance efforts to develop an effective vaccine for hepatitis C.
Topography images with scan widths as small as 100 nm were acquired in a droplet of buffer solution in small-amplitude tapping mode on the Cypher ES AFM. In addition, over 100 force curves were acquired on single, intact VLPs of each type. In both cases, measurement repeatability was enhanced by the ES’s sealed cell, which minimized buffer evaporation and temperature fluctuations. The high spatial resolution, ultralow noise floor, and high force sensitivity of Cypher AFMs further ensured high measurement precision and accuracy. Built-in software for force curve analysis streamlined calculations of elastic (Young’s) modulus.
Citation: S. Collett, J. Torresi, L. Earnest-Silveira et al., Probing and pressing surfaces of hepatitis C virus-like particles. J. Colloid Interface Sci. 45, 259 (2019). https://doi.org/10.1016/j.jcis.2019.03.022
Note: The data shown here are reused under fair use from the original article, which can be accessed through the article link above.