title: Terahertz spectroscopic differentiation of microstructures in protein gels.
abstract: We demonstrate that terahertz (THz) spectroscopy can be used to differentiate soft protein microstructures. Differentiation of soft microstructures in gels has to date been performed using optical imaging techniques (e.g. electron microscope), but a non-destructive differentiation tool is lacking. Particulate and fine-stranded (fibrillar) soft protein microstructures are of interest, particularly to medical researchers, because they form from naturally occurring proteins that are thought to be involved in several human diseases, such as Alzheimer's disease. In this study, globular beta-lactoglobulin structures with diameters of 2 microm, and fibrillar structures with diameters less than 0.03 microm are observed between 0.8 and 1.5 THz. Results show that the globular structures have a decline in THz transmission when compared to the fibrillar ones. The cause of this decline is possibly due to Rayleigh scattering from the globular microstructures.
authors: Centre for Biomedical Engineering, School of Electrical and Electronic Engineering, University of Adelaide, Adelaide, SA 5005, Australia. gretel.png@adelaide.edu.au
authors: Gretel M
authors: GM
authors: Png
authors: Robert J
authors: RJ
authors: Falconer
authors: Bernd M
authors: BM
authors: Fischer
authors: Hidayatul A
authors: HA
authors: Zakaria
authors: Samuel P
authors: SP
authors: Mickan
authors: Anton P J
authors: AP
authors: Middelberg
authors: Derek
authors: D
authors: Abbott
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism; D000818:Animals; D002417:Cattle; D005782:Gels; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007782:Lactoglobulins / Q000737:chemistry; D008968:Molecular Conformation; D055095:Optics and Photonics; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D013055:Spectrophotometry, Infrared / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D055068:Terahertz Spectroscopy / Q000379:methods*
chemical_list: D005782:Gels; D007782:Lactoglobulins; D011506:Proteins