TY  - JOUR
A1  - Murib, Mohammed Sharif
A1  - Yeap, Weng-Siang
A1  - Martens, Daan
A1  - Bienstman, Peter
A1  - Ceuninck, Ward de
A1  - Grinsven, Bart van
A1  - Schöning, Michael Josef
A1  - Michiels, Luc
A1  - Haenen, Ken
A1  - Ameloot, Marcel
A1  - Serpengüzel, Ali
A1  - Wagner, Patrick
T1  - Photonic detection and characterization of DNA using sapphire microspheres
JF  - Journal of biomedical optics
N2  - A microcavity-based deoxyribonucleic acid (DNA) optical biosensor is demonstrated for the first time using synthetic sapphire for the optical cavity. Transmitted and elastic scattering intensity at 1510 nm are analyzed from a sapphire microsphere (radius 500  μm, refractive index 1.77) on an optical fiber half coupler. The 0.43 nm angular mode spacing of the resonances correlates well with the optical size of the sapphire sphere. Probe DNA consisting of a 36-mer fragment was covalently immobilized on a sapphire microsphere and hybridized with a 29-mer target DNA. Whispering gallery modes (WGMs) were monitored before the sapphire was functionalized with DNA and after it was functionalized with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The shift in WGMs from the surface modification with DNA was measured and correlated well with the estimated thickness of the add-on DNA layer. It is shown that ssDNA is more uniformly oriented on the sapphire surface than dsDNA. In addition, it is shown that functionalization of the sapphire spherical surface with DNA does not affect the quality factor (Q≈104) of the sapphire microspheres. The use of sapphire is especially interesting because this material is chemically resilient, biocompatible, and widely used for medical implants.
Y1  - 2014
U6  - http://dx.doi.org/10.1117/1.JBO.19.9.097006
SN  - 1560-2281 (E-Journal); 1083-3668 (Print)
VL  - 19
IS  - 9
SP  - 097006
PB  - SPIE
CY  - Bellingham
ER  -