2011, Vol.14, No.3, pp.253-263
A novel technique for the label-free analysis of micro and
nanoparticles including biomolecules using optical micro cavity
resonance of whispering-gallery-type modes is being developed.
Various schemes of the method using both standard and specially
produced microspheres have been investigated to make further
development for microbial application. It was demonstrated that
optical resonance under optimal geometry could be detected under
the laser power of less than 1 microwatt. The sensitivity of
developed schemes has been tested by monitoring the spectral shift
of the whispering gallery modes. Water solutions of ethanol,
ascorbic acid, blood phantoms including albumin and HCl, glucose,
biotin, biomarker like C reactive protein as well as bacteria and
virus phantoms (gels of silica micro and nanoparticles) have been
used.
Structure of resonance spectra of the solutions was a specific subject of
investigation. Probabilistic neural network classifier for biological agents
and micro/nano particles classification has been developed. Several
parameters of resonance spectra such as spectral shift, broadening, diffuseness
and others have been used as input parameters to develop a network
classifier for micro and nanoparticles and biological agents in solution.
Classification probability of approximately 98 % for probes under
investigation have been achieved.
Developed approach have been demonstrated to be a promising technology
platform for sensitive, lab-on-chip type sensor which can be used for
development of diagnostic tools for different biological molecules, e.g.
proteins, oligonucleotides, oligosaccharides, lipids, small molecules, viral
particles, cells as well as in different experimental contexts e.g.
proteomics, genomics, drug discovery, and membrane studies.
Key words:
optical resonance, whispering gallery mode, dielectric
microspheres, micro and nanoparticles, biological agents, neural network
analysis, classification
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