Report on the use of Optical Tweezers in the Schieber Research Group at Illinois Institute of Technology

JPK Instruments reports on the use of their NanoTracker™ optical tweezers system to study collagen fibrils at Illinois Institute of Technology in Chicago.

The Schieber Research Group is led by Jay Schieber, Professor of Chemical Engineering at the Illinois Institute of Technology where he is also Director of the Center for Molecular Study of Condensed Soft Matter. Current research focuses on the kinetic theory of macromolecules to model the rheological, thermodynamic and thermal behaviour of polymeric fluids. These models are then used to predict the properties of advanced materials during and after processing.

The group purchased a JPK Instruments NanoTracker™ to help them to investigate micro-rheological processes. Micro-rheology (or microbead rheology) is a fairly new branch of rheology. It allows the measurement of the viscoelastic properties of media by tracking thermal fluctuations of Brownian particles contained in the media. The key value of this method is the resolution of the tracking.

The early work with NanoTracker™ took a different direction. One of the post-doctoral workers is Pavel Dutov. He has looked extensively at the use of optical tweezers and published a paper with Professor Schieber on the calibration of optical traps by dual trapping of one bead. Mr Dutkov also studied the elastic modulus of collagen fibre before embarking on the micro-rheological work with the study of collagen type I gel. Here, he looked at the anisotropic viscoelastic properties of the gel as these are very important aspects for wound healing biomedicine and there is no other experimental method can be used for such studies.

In the measurement of collagen single fibre elastic modulus, NanoTracker™ has shown precision unreachable by use of AFM alone and has the ability to conduct experiments in conditions close to those in vivo. For the anisotropic microbead rheology experiments, NanoTracker™ provided great combination of spatial and temporal resolution with data analysis transparency.