Whispering Gallery Mode Resonators for Rapid Label-Free Biosensing in Small Volume Droplets

Biosensors

Sarah M. Wildgen¹  Robert C. Dunn² 

[1] Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, 2030 Becker Drive, Lawrence, KS 66047, USA; E-Mail

关键词: whispering gallery mode resonators;    label-free;    small volume;    rapid assay;    real time analysis;    sessile droplets;   

DOI  :  10.3390/bios5010118

来源: mdpi

【 摘 要 】

Rapid biosensing requires fast mass transport of the analyte to the surface of the sensing element. To optimize analysis times, both mass transport in solution and the geometry and size of the sensing element need to be considered. Small dielectric spheres, tens of microns in diameter, can act as label-free biosensors using whispering gallery mode (WGM) resonances. WGM resonances are sensitive to the effective refractive index, which changes upon analyte binding to recognition sites on functionalized resonators. The spherical geometry and tens of microns diameter of these resonators provides an efficient target for sensing while their compact size enables detection in limited volumes. Here, we explore conditions leading to rapid analyte detection using WGM resonators as label-free sensors in 10 μL sample droplets. Droplet evaporation leads to potentially useful convective mixing, but also limits the time over which analysis can be completed. We show that active droplet mixing combined with initial binding rate measurements is required for accurate nanomolar protein quantification within the first minute following injection.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.