Professor Lynn Penn at Drexel University talks about their QCM-D research
Lynn Penn’s research group in the Department of Chemistry at Drexel University (Philadelphia, USA) uses QCM-D to study conformational changes caused by interaction of free species with macromolecules immobilized at surfaces. Distinct changes in frequency and dissipation occur as a result of interaction of free species with the immobilized layer, be it protein or a synthetic polymer brush. With the QCM-D, these changes can be followed in real-time, in situ, for extended periods if necessary.
"Using the QCM-D, we have been able to elucidate the conformational changes exhibited by both free species and immobilized layer as they interact in the flow cell of the instrument. The QCM-D curve-fitting software permits characterization of the mechanical properties of the viscoelastic layers that we study. In addition, the software allows determination of the height of the immobilized layer, which is of crucial importance in the case of polymer brushes. By using change of solvent to collapse the viscoelastic layer into an ultra-thin, elastic layer in the flow cell, we can make quantitative determinations of the mass of the immobilized macromolecules directly from the frequency change", Penn Lynn describes.
We use the QCM-D to study macromolecular systems in both aqueous and organic solvent systems. With it we can examine temperature stability of the layers we deposit and reversibility of the processes we observe. Because of the QCM-D’s extreme sensitivity, we also use it to develop successful procedures for surface modification. The versatility of the QCM-D makes it the workhorse instrument in our laboratory. In fact, we found it so useful that we purchased two instruments, Penn Lynn ends.
Want to know more about Professor Lynn Penn and her research? Click here to read a one page summary of her research or read one of her papers; Hyun-Su Lee and Lynn S. Penn, “In Situ Study of Polymer Brushes as Selective Barriers to Diffusion,” Macromolecules, 2008, 41, 8124-8129.
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