The Design and Applications of Nanoparticle Coated Microspheres in Immunoassays

Abstract

Nanoparticle coated microspheres are composed of two or more materials with a core/shell structure and exhibit unique abilities that allow amplification of trace targets in immunoassays. The preparation of nanoparticle coated microspheres can be accomplished using three main strategies: (1) in-situ, (2) ex-situ, and (3) hollow sphere methods. Antibodies or biomolecules can be immobilized on the surface of nanoparticle coated microspheres or hollow spheres to carry out detection of targets using surface-enhanced resonance spectroscopy (SERS), fluorescence, electrochemistry, and many others. Using these particles as antibody carriers in SERS-based immunoassays, broad dynamic range and low detection limits, and improved selectivity can be realized. By assistance of nanoparticle coated microspheres in immunoassays, improved sensitivity and selectivity has been realized. In this review, nanoparticle coated microsphere generation, recent applications, and future potential with respect to immunoassays are discussed.

Label-free surface-enhanced Raman spectroscopy of biofluids: fundamental aspects and diagnostic applications

“…chemical species (usually dyes) having an intense, stable, and well-recognizable SERS spectrum used to signal the presence of the analyte of interest [9,[12][13][14]. The systems constituted by such labels adsorbed on one or more metal nanoparticles are often referred to as SERS Blabels^, Bmarkers^, or Btags^and are the basis of SERS immunoassays, qualitative or quantitative tests to detect specific disease markers using antibodies [15][16][17][18][19][20]. SERS immunoassays, because of their sensitivity and their multiplexing potential (i.e.…”

“…SERS immunoassays, because of their sensitivity and their multiplexing potential (i.e. the possibility of simultaneously detecting more than one analyte in a single test), have gained increasing popularity for biofluids diagnostics, and have been recently reviewed elsewhere [17,18,20,21].…”

Polymeric microellipsoids with programmed magnetic anisotropy for controlled rotation using low (≈10 mT) magnetic fields

“…Spherical magnetic beads already play an important role in microfluidics; they can be made to link to target species and can be used for manipulation and/or detection in lab-on-achip systems [8][9][10] and protein and biomolecular purification and mixing. They are also used for generating and measuring forces at the micrometre scale in biophysical studies, [11][12][13] in torquegenerating assays, [14] cellular mechanotransduction and microrheology, in magnetic twisting cytometry, [15,16] in cellular, protein and nucleic acid manipulation in separation assays, [17] in immunoassays, [18] in magnetic flow cytometry, [19] in magnetic separation in lab-on-a-chip microfluidic systems, [20] in directed hyperthermia applications [11,21] and targeted drug delivery. [22] Most applications use commercial spherical MPC microparticles consisting of a polymeric matrix that confines magnetic spherical superparamagnetic Fe 3 O 4 nanoparticles (NPs).…”

Remotely actuated polymeric nanocomposites for biomedical applications

“…Magnetic microparticles have been used to study the bacterial flagellar motor in torquegenerating assays [155], cellular mechanotransduction and microrheology with magnetic twisting cytometry [277,278], cellular, protein and nucleic acid manipulation in separation assays as immunomagnetic isolation [274], immunoassays [279], magnetic flow cytometry [280] or in magnetic separation in lab-on-a-chip microfluidic systems [281] and other microfabricated devices, as well as in directed hyperthermia applications [160,161] and targeted drug delivery [159]. Most applications use commercial spherical MPC microparticles or colloids consisting of a polymeric matrix that confines magnetic spherical nanoparticles (NPs), mainly superparamagnetic Fe 3 O 4 NPs.…”