Optical Glass Microsphere Enabled Rapid Single‐Molecular Fluoroimmunoassay

Abstract

Determination of low-abundance proteins in body liquid is the significant strategy for the early diagnosis of diseases and the discovery of signal paths in pathobiology. Here, the limit of detection of 113 aM for model human IgA is successfully obtained by the fluoroimmunoassay developed on an optical soda lime glass microsphere in micrometers that is illumed by the microsphere amplified fluorescence (MAF), which can be identified to the most sensitive immunoassay so far. In this case, the fluorescence signal of fluoroimmunoassay can be physically amplified by MAF while the large reacting area will be supplied by the glass microsphere to complete the fluoroimmunoassay. Therefore, the assay time of the fluoroimmunoassay can be shortened to 12 min via the optical glass microsphere-enabled ultrasensitive fluoroimmunoassay at the same time. The developed fluoroimmunoassay indicates a possibility to perform the ultrasensitive immunoassay on the optical glass microsphere in 10 min and more, which may greatly facilitate the development of the ultrasensitive immunoassay for the urgent measurements and promote the development of portable fluoroimmunoassay.

Microsphere-Enhanced Fluorescence-Lightened Solid-Phase Hybridization Assay: The Strategy to Highly Selective Detection of Micro Ribonucleic Acids

“…MSEF was demonstrated to be a effectual way to amplify the fluorescence emission and was utilized to develop the sensitive fluorescence assay such as the ultrasensitive fluoroimmunoassay in the previous research. 25 The main mechanism of MSEF performing the sensitive fluorescence detection was that the asymmetric angular transmission would occur at the inhomogeneous two-phase interface and the fluorescence emission could further orient to the optical spherical medium with a high refractive index. Therefore, the fluorescence signal detected through the optical microsphere could be dramatically enhanced.…”

Augmented Fluorescence Signaling on a Single BaTiO3 Microbead Optical Booster toward High-Sensitive Biosensing

“…This process will create an exponentially decaying evanescent field on the surface of the BTM, which is capable of exciting the QDs continuously at the contact interface. ,, In this case, both the direct incident light and the evanescent waves yielded by WGM can excite all of the QDs anchored on the surface of BTM, therefore improving the excitation efficiency to yield augmented fluorescence (Figure c). Moreover, according to literature reports, when the fluorophore is located at the two-phase interface, most of the fluorescence emitted at the interface will be oriented to the phase with a higher refractive index at a certain contribution angle. − This means that apart from the amplified excitation efficiency, BTM may also perform as an optical lens to focus the emission light and thus obviously improve the efficiency of fluorescence signal collection . Hence, the inherent optical enhancement effects, together with the highly concentrated signal-enriching effect on a single BTM, make it an ideal optical booster to facilitate high-performance single microbead-based bioassays.…”