生物膜是細胞重要的組成成分，其分子結構為生物領域的重要課題，尺度為3-5nm，故X光是量測生物膜結構的利器。X光繞射可用來量測多片層生物膜樣品的電子密度，以研究生物膜的精細結構；而X光散射技術則用來測量生物單層膜微胞在溶液中的膜厚度，可以更接近細胞生存的環境。同步輻射X光具有高強度、高準直性及小光束尺寸的優點，應用在生物樣品的量測將會有很大的優勢。

Bio-membrane is the important component of cell and its structure is the key issue in biology field. Due to the scale of structure is about 3-5 nm, X-ray is the powerful tool to measure the structure of membrane. Using X-ray diffraction to determine the electron density profile of lamellar membrane sample, we can study fine structure of bio-membrane. X-ray scattering on small unilamellar vesicles (SUVs) sample can be used to probe membrane thickness in solution. The conditions are more close to which the real cell live in. Synchrotron radiation X-ray source has good properties of high flux, high collimation and small beam size. Using synchrotron light source on biological sample study should be most advantaged.