An integrated laser-tweezers instrument for microanalysis of individual protein aggregates

作者：Mao Hanbin^*; Luchette Paul

来源：Sensors and Actuators B: Chemical , 2008, 129(2): 764-771.

DOI：10.1016/j.snb.2007.09.052

• power spectrum
• confocal fluorescence spectroscopy
• confocal raman spectroscopy
• clouding temperature
• aqueous two phase systems
• protein aggregates

Herein we introduce a new laser-tweezers instrument capable of providing both physical and chemical information of individually trapped protein aggregates. These capabilities were demonstrated by investigating the aggregation process of alpha-elastin droplets of nanometers to micrometers in diameter. Individual droplets of aggregated elastin molecules were trapped at the focus of a 1064 nm near infrared (NIR) laser in the instrument. The size of these individual elastin aggregates was inferred by recording their thermal motion at a frequency of 100 kHz using a position sensitive photodetector (PSPD). The chemical information of the trapped particles was revealed by confocal fluorescence and confocal Raman spectroscopies using 532-nm laser excitation. Background signals outside trapped particles were eliminated by a pinhole in back reflected geometry. Both physical and confocal fluorescence measurements revealed a transition temperature of 38 degrees C for a fast process in individual elastin aggregates, a value consistent with the clouding temperature in bulk. Confocal Raman spectroscopy yielded a transition temperature of 35 degrees C for a slow process characteristic of the formation of elastin aqueous two phase systems (ATPS).

• 出版日期2008-2-22