Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Nanomechanical properties of a-synuclein amyloid fibrils: a comparative study by nanoindentation, harmonic force microscopy, and Peakforce QNM | Sweers et al. Nanoscale Research Letters 2011 6 270 http content 6 1 270 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Nanomechanical properties of a-synuclein amyloid fibrils a comparative study by nanoindentation harmonic force microscopy and Peakforce QNM Kim Sweers Kees van der Werf Martin Bennink and Vinod Subramaniam Abstract We report on the use of three different atomic force spectroscopy modalities to determine the nanomechanical properties of amyloid fibrils of the human a-synuclein protein. a-Synuclein forms fibrillar nanostructures of approximately 10 nm diameter and lengths ranging from 100 nm to several microns which have been associated with Parkinson s disease. Atomic force microscopy AFM has been used to image the morphology of these protein fibrils deposited on a flat surface. For nanomechanical measurements we used single-point nanoindentation in which the AFM tip as the indenter is moved vertically to the fibril surface and back while the force is being recorded. We also used two recently developed AFM surface property mapping techniques Harmonic force microscopy HarmoniX and Peakforce QNM. These modalities allow extraction of mechanical parameters of the surface with a lateral resolution and speed comparable to tapping-mode AFM imaging. Based on this phenomenological study the elastic moduli of the a-synuclein fibrils determined using these three different modalities are within the range GPa. We discuss the relative merits of these three methods for the determination of the elastic properties of protein fibrils particularly considering the differences and difficulties of each method. Introduction Amyloid fibrils are insoluble protein aggregates that have been associated with a range of neurodegenerative diseases including Huntington Alzheimer s Parkinson s and Creutzfeldt-Jakob disease 1 . The fibrils typically have a diameter ranging from 4 to 12 nm and lengths from 100 nm up to .
