Casper Hyttel Clausen, DTU Nanotech, 4525-5829 (casper.clausen@nanotech.dtu.dk)

Winnie Svendsen, DTU Nanotech, 4525-5731 (wisv@nanotech.dtu.dk)

In today’s lab on a chip (LOC) systems sorting of biological material has gained increasing interest, different methods can be applied depending on the different properties of the sample. In the C-TAS (chromosome total analysis system) project we work with a sorting methods based on the electrical properties of chromosomes. In order to fully utilise these sorting methods the physical properties of the sample in question needs to be known. Unfortunately the electrical properties of chromosomes are largely unknown. Therefore the properties of biological material are in need to be mapped. In this project we map the physical properties of chromosomes using a method called electrostatic force microscopy (EFM). This method uses a conducting atomic force microscopy (AFM) cantilever which scans the surface as in standard non-contact AFM, while a potential is applied to the sample surface. An electrical field is applied between the tip of the cantilever and the surface. When scanning the surface, variations (on the surface) will induce changes in the field which will be recorded by change in the deflection of the AFM cantilever. The tip surface system can be modelled as a plate capacitor this will be used to gain quantitative information about the chromosomes in question.

This project is experimental and you will work with an AFM system in an advanced mode to obtain the data, while data analysing will be done in MATLAB. Further we will go over the theory behind the tip surface interacting.