Surface analysis techniques

biomat engineering department applies the proper surface analysis techniques both to diagnostic and medical devices in order to:


TECHNIQUE DESCRIPTION APPLICATIONS
BIOLOGICAL, CHEMICAL AND PHYSICAL ASSAYS special tests, ranging from different ELISA assays to customised test (e.g. the measurement of friction of catheters), are studied and developed for testing the device's performance: according with the device's characteristics and with the expected performance, proper techniques are developed and applied in order to study its behaviour
AFM
(Atomic Force Microscopy)
a tip scans the surface to be examined: its deviations, due to interatomic forces between tip's apex and device's surface, are measured by an optical system and translated into atomic resolution images for controlling and measuring on a nanometric scale the device's surface conditions, it can be applied virtually to any material and namely to polymers. The possibility to operate also in liquid environment. allows to detect biomolecules attached on the surface
ESCA or XPS
(X-ray Photoelectron Spectroscopy)
sample is bombarded by X-rays which cause it to emit electrons. The measurement of quantity and energy of electrons made by an electron analyser gives qualitative and quantitative information of the composition of the very first layer of the surface for analysing the surface composition in order to:
  • check the transformations which are induced by surface treatments
  • detect otherwise undetectable contamination
SEM / EDS
(Scanning Electron Microscopy)
sample is bombarded by electrons which cause it to emit X-rays . The analysis of emission gives qualitative image of the surface for checking the device's surface. State of the art imaging system allows to have a "photograph of the surface with a resolution up to 1 µm and information above its composition
CA
(Contact Angle)
a drop of liquid is deposited on the device's surface and the angle formed between the drop and the solid surface is measured with a microscope equipped with a goniometer to check the wettability of the device: the value of surface tension obtained through Contact Angle measurement is a fast and powerful instrument for the detection of polymers surface conditions