title: Ultrastructural and elemental imaging of biological specimens by soft X-ray contact microscopy.
abstract: Soft X-ray contact microscopy offers a means of visualizing unstained as well as stained biological materials at better than 6 nm resolution. Unlike light and transmission electron microscopy, which rely on stains to increase specimen contrast, soft X-ray imaging is dependent upon the differential absorption of incident soft (1-10nm wavelength) X-rays by the endogenous elements within the specimen. The advantages of using soft X-rays for imaging are: 1) reduced specimen damage during exposure; 2) ability to image hydrated specimens at atmospheric pressure; 3) ability to image specimens ranging in thickness from less than 40 nm to as much as 10 microns; and 4) ability to map the elemental composition of the specimen through observation of the differential absorption of properly chosen incident x-ray wave lengths. This paper explains the principles of the image formation and demonstrates the use of soft X-ray contact microscopy with biological samples which could not readily be imaged in their natural form using conventional electron microscopy methods.
mesh_terms: D000818:Animals; D001048:Aplysia; D002417:Cattle; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D004577:Electron Probe Microanalysis / Q000379:methods*; D006652:Histological Techniques; D006801:Humans; D009412:Nerve Fibers / Q000648:ultrastructure; D009474:Neurons / Q000648:ultrastructure; D010857:Pigment Epithelium of Eye / Q000648:ultrastructure; D011509:Proteoglycans / Q000032:analysis
chemical_list: D011509:Proteoglycans