抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Microcavity physics and design will be reviewed. Following an overview of applications in quantum optics, communications and biosensing, recent advances in ultra-high-Q research will be presented.

Optical microcavities

We demonstrate microfabrication of ultra-high-Q microcavities on a chip, exhibiting a novel toroid-shaped geometry. The cavities possess Q-factors in excess of 100 million which constitutes an improvement close to 4 orders-of-magnitude in Q compared to previous work [B. Gayral, et al., 1999].

Ultra-high-Q toroid microcavities on a chip

Sensitive optical biosensors for unlabeled targets: a review.

Optical label-free detectors, such as the venerable surface plasmon resonance (SPR) sensor, are generally favored for their ability to obtain quantitative data on intermolecular binding. However, before the recent introduction of resonant microcavities that use whispering gallery mode (WGM) recirculation, sensitivity to single binding events had not materialized. Here we describe the enhancement mechanisms responsible for the extreme sensitivity of the WGM biosensor, review its current implementations and applications, and discuss its future possibilities.

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Whispering-gallery-mode biosensing: label-free detection down to single molecules

We present an optical biosensor with unprecedented sensitivity for detection of unlabeled molecules. Our device uses optical resonances in a dielectric microparticle (whispering gallery modes) as the physical transducing mechanism. The resonances are excited by evanescent coupling to an eroded optical fiber and detected as dips in the light intensity transmitted through the fiber at different wavelengths. Binding of proteins on the microparticle surface is measured from a shift in resonance wavelength. We demonstrate the sensitivity of our device by measuring adsorption of bovine serum albumin and we show its use as a biosensor by detecting streptavidin binding to biotin.

/pdf/protein-detection-by-optical-shift-of-a-resonant-microcavity-1swrn97w7l.pdf

Protein detection by optical shift of a resonant microcavity

Biosensors based on the shift of whispering-gallery modes in microspheres accompanying protein adsorption are described by use of a perturbation theory. For random spatial adsorption, theory predicts that the shift should be inversely proportional to micorsphere radius R and proportional to protein surface density and excess polarizability. Measurements are found to be consistent with the theory, and the correspondence enables the average surface area occupied by a single protein to be estimated. These results are consistent with crystallographic data for bovine serum albumin. The theoretical shift for adsorption of a single protein is found to be extremely sensitive to the target region, with adsorption in the most sensitive region varying as 1R 52 . Specific parameters for single protein or virus particle detection are predicted. © 2003 Optical

/pdf/shift-of-whispering-gallery-modes-in-microspheres-by-protein-4qu9dxzrau.pdf

Shift of whispering-gallery modes in microspheres by protein adsorption

Preface. Models of Polymer Chains. Thermodynamics of Dilute Polymer Solutions. Dynamics of Dilute Polymer Solutions. Thermodynamics and Dynamics of Semidilute Solutions. References. Further Readings. Appendix A1: Delta Function. Appendix A2: Fourier Transform. Appendix A3: Integrals. Appendix A4: Series. Index.

Polymer solutions: An introduction to physical properties

https://www.biosystems.physik.uni-muenchen.de/paperpdfs/dna_microcavity.pdf

Iwao Teraoka

Papers

Protein detection by optical shift of a resonant microcavity

Shift of whispering-gallery modes in microspheres by protein adsorption

Polymer solutions: An introduction to physical properties

Multiplexed DNA quantification by spectroscopic shift of two microsphere cavities.

Polymer solutions