title: Slotted photonic crystal cavities with integrated microfluidics for biosensing applications.
abstract: 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.
authors.affiliation: School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, Scotland, UK. mgs32@st-andrews.ac.uk
authors.forename: M G
authors.initials: MG
authors.lastname: Scullion
authors.forename: A
authors.initials: A
authors.lastname: Di Falco
authors.forename: T F
authors.initials: TF
authors.lastname: Krauss
mesh_terms: D001360:Avidin / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods*; D003460:Crystallization; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D008027:Light; D008689:Methacrylates / Q000737:chemistry; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D017785:Photons; D012680:Sensitivity and Specificity; D012828:Silicones / Q000737:chemistry
chemical_list: D004129:Dimethylpolysiloxanes; D008689:Methacrylates; D012828:Silicones; C115833:poly(dimethylsiloxane methacrylate); D001360:Avidin