title: Trapping-assisted sensing of particles and proteins using on-chip optical microcavities.
abstract: An improved ability to sense particles and biological molecules is crucial for continued progress in applications ranging from medical diagnostics to environmental monitoring to basic research. Impressive electronic and photonic devices have been developed to this end. However, several drawbacks exist. The sensing of molecules is almost exclusively performed via their binding to a functionalized device surface. This means that the devices are seldom reusable, that their functionalization needs to be decided before use, and that they face the diffusion bottleneck. The latter challenge also applies to particle detection using photonic devices. Here, we demonstrate particle sensing using optical forces to trap and align them on waveguide-coupled silicon microcavities. A second probe laser detects the trapped particles by measuring the microcavity resonance shift. We also apply this platform to quantitatively sense green fluorescent proteins by detecting the size distribution of clusters of antibody-coated particles bound by the proteins.
authors: School of Engineering and Applied Sciences, Harvard University, 33 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors: Shiyun
authors: S
authors: Lin
authors: Kenneth B
authors: KB
authors: Crozier
mesh_terms: D049452:Green Fluorescent Proteins / Q000032:analysis*; D055616:Microtechnology / Q000295:instrumentation*; D052898:Optical Tweezers; D010316:Particle Size; D011137:Polystyrenes / Q000032:analysis* / Q000737:chemistry
chemical_list: D011137:Polystyrenes; D049452:Green Fluorescent Proteins