Microsphere-based interferometric optical probe

Abstract

Fluorescent optical probes have rapidly transformed our understanding of complex biological systems by providing specific information on biological targets in the natural living state. However, their utility is often limited by insufficient brightness, photostability, and multiplexing capacity. Here, we report a conceptually new optical probe, termed ‘reflectophore’, which is based on the spectral interference from a dielectric microsphere. Reflectophores are orders-of-magnitudes brighter than conventional fluorophores and are free from photobleaching, enabling practically unlimited readout at high fidelity. They also offer high-degree multiplexing, encoded in their optical size, which can be readily decoded through interferometric detection with nanoscale accuracy, even in turbid biological media. Furthermore, we showcase their biological applications in cellular barcoding and microenvironmental sensing of a target protein and local electric field.

All-optical observation on activity-dependent nanoscale dynamics of myelinated axons

“…SpeRe was previously applied for measuring nanoscale morphological dynamics, such as osmotic swelling of myelinated axons or protein adhesion to a functionalized microsphere. 19 , 25 To further verify the subnanometer-scale precision of our SpeRe readout, we used a finely tapered glass fiber prepared by thermally drawing a glass rod using a micropipette puller ( Fig. 2 ).…”

Optical-resonance-assisted generation of super monodisperse microdroplets and microbeads with nanometer precision

“…35 WGMs are limited to the droplets with high enough refractive index contrast and large enough size. Alternatively, size monitoring could be performed by spectroscopy of reflected white light, 36 which can be applied for smaller droplets, even below 1 μm. Recently, multi-cell tagging was demonstrated by the introduction of polymer beads 25 or micrometer sized semiconductor disks 26 into the cell interior.…”

Microcavity- and Microlaser-Based Optical Barcoding: A Review of Encoding Techniques and Applications

“…51,52 To generate a unique reflection spectrum, interference effects can also be employed, as in the case of reflections from a dielectric spherical particle. 53 Microcavity-and microlaser-based barcodes are generally categorized as spectral barcodes, since the information is encoded in the spectrum. However, less often the information can also be encoded using other mechanisms, such as intensity, laser threshold, and polarization.…”