Detection of protein orientation on the silica microsphere surface using transverse electric/transverse magnetic whispering gallery modes.
نویسندگان
چکیده
The state of adsorbed protein molecules can be examined by comparing the shifts in a narrow line resonance wavelength of transverse electric (TE) and transverse magnetic (TM) whispering gallery modes (WGM) when the molecules adsorb onto a transparent microsphere that houses WGM. In adsorption of bovine serum albumin (BSA) onto an aminopropyl-modified silica microsphere, the TM/TE shift ratio indicated highly anisotropic polarizability of BSA in the direction normal to the surface, most likely ascribed to anchoring the heart-shaped protein molecule by one of its tips. The polarization-dependent resonance shift was confirmed when the surrounding refractive index was uniformly changed by adding salt, which would simulate adsorption of large objects.
منابع مشابه
Ultra-Sensitive Optical Biosensor Based on Whispering Gallery Modes: The Effect of Buffer Solutions Refractive Index on Their Sensitivity and Performance
Background: Whispering gallery modes (WGM) biosensors are ultrasensitive systems that can measure amount of adsorbed layer onto the micro-cavity surface. They have many applications including protein, peptide growth, DNA and bacteria detection, molecular properties measurements and specific interaction and drug table recognitions due to their high sensitivity, compact size and label free sensin...
متن کاملProbing Stress-Induced Optical Birefringence of Glassy Polymers by Whispering Gallery Modes Light Localization
An optical resonance method for the determination of the strain- and stress-optical coefficients of optically transparent polymers is presented and exemplified for monodisperse and bidisperse molecular weight polystyrene (PS). This method employs whispering gallery modes (WGMs) resonation inside a spheroid polymeric cavity, suspended on an optical fiber taper waist, which, in turn, is used for ...
متن کاملWhispering gallery modes and other cavity modes for perfect backscattering and blazing.
We demonstrate the possibility to obtain perfect blazing both in Littrow and off-Littrow mountings using diffractive systems consisting of a plane metallic substrate and dielectric structures that can support cavity modes. The resonances are located at a relatively large distance between the metal and the dielectric structure, a condition that prevents the resonance increase of absorption. The ...
متن کاملDirectly mapping whispering gallery modes in a microsphere through modal coupling and directional emission
We fabricate slightly deformed fused-silica microspheres in which whispering gallery modes possess remarkably directional escape emission from the microsphere boundary. With efficient free-space excitation and collection, the lateral spatial distribution of whispering gallery modes with different azimuthal mode numbers, m, is directly observed through modal coupling and directional emission. Ex...
متن کاملRoom temperature lasing of InAs/GaAs quantum dots in the whispering gallery modes of a silica microsphere.
We have achieved low threshold lasing of self-assembled InAs/GaAs quantum dots coupled to the evanescent wave of the high-Q whispering gallery modes of a silica microsphere. In spite of high temperature and Q-spoiling of whispering gallery modes due to diffusion and refraction on the high index semiconductor sample, room temperature lasing is obtained with less than 100 quantum dots. This resul...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Biophysical journal
دوره 92 12 شماره
صفحات -
تاریخ انتشار 2007