Slotted photonic crystal cavities with integrated microfluidics for biosensing applications

• Published in: Biosensors & bioelectronics Vol. 27; no. 1; pp. 101 - 105
• Main Authors: Scullion, M.G., Di Falco, A., Krauss, T.F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-09-2011; Elsevier
• Subjects: Avidin - analysis; Biological and medical sciences; Biosensing Techniques - methods; Biosensors; Biotechnology; Crystallization; Density; Detection; Dimethylpolysiloxanes - chemistry; Fundamental and applied biological sciences. Psychology; Holes; Light; Methacrylates - chemistry; Methods. Procedures. Technologies; Microfluidic; Microfluidic Analytical Techniques - methods; Microfluidics; Optical biosensor; Photonic crystal; Photonic crystals; Photons; Sensitivity and Specificity; Silicones - chemistry; Slot waveguide; Slotted photonic crystal; Surface area; Various methods and equipments; Wavelengths; Slot waveguide; Slotted photonic crystal; Photonic crystal; Optical biosensor; Microfluidic; Fluid mechanics; Crystals; Optical sensor; Waveguide; Biosensor; Miniaturization; Application; Microfluidics
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2011.06.023

We demonstrate the detection of dissolved avidin concentrations as low as 15
nM or 1
μg/ml using functionalized slotted photonic crystal cavities with integrated microfluidics. With a cavity sensing surface area of approximately 2.2
μm
2, we are able to detect surface mass densities of order 60
pg/mm
2 corresponding to a bound mass of approximately 100
ag. The ultra-compact size of the sensors makes them attractive for lab-on-a-chip applications where high densities of independent sensing elements are desired within a small area. The high sensitivity over an extremely small area is due to the strong modal overlap with the analyte enabled by the slotted waveguide cavity geometry that we employ. This strong overlap results in larger shifts in the cavity peak wavelength when compared to competing approaches.