Fluoroimmunoassay for Antigen Based on Fluorescence Resonance Energy Transfer Between Quantum Dots and Gold Nanoparticles

Abstract

A unique, sensitive, and highly specific fluoroimmunoassay system for antigen detection using quantum dot and gold nanoparticles has been developed. The assay is based on the fluorescence quenching of quantum dots caused by gold nanoparticles coated with antibody. To demonstrate its analytical capabilities, the quantum dots were coated with anti-HBsAg monoclonal antibodies (QDs-MAb1) and gold nanoparticles coated with another anti-HBsAg monoclonal antibodies ( GNPs-MAb2) which specifically bound with HBsAg could sandwich the HBsAg captured by the immunoreactions. The sandwich-type immunocomplex was formed and the energy of quantum dots was transferred to gold nanoparticles as they were within a short distance, so that the fluorescence intensity of quantum dots was quenched. The fluorescence intensity of quantum dots at 570 nm was negative linear proportional to HBsAg concentration logarithm. The result showed that the limit of detection of the HBsAg was 0.928 ng/mL. This new system can be extended to detect target molecules with matched antibodies and has broad potential applications in immunoassay and disease diagnosis.

High-Throughput Crystallization of l-Alanine Using iCrystal Plates and Metal-Assisted and Microwave-Accelerated Evaporative Crystallization

“…The field of plasmonic materials has gained notable interest due to their thermal conductive abilities that can be utilized in a wide range of applications. − Plasmonic materials also have coherent oscillations of conduction electrons due to the interactions of light with the metal dielectric environment. ,,− Some plasmonic materials, such as silver, copper, gold, and nickel, have been utilized in numerous applications in biotechnology. − For example, silver and gold have optical properties that are useful in diagnostic devices due to the distinct bright colors they display during plasmon resonance. ,− Nickel nanostructures which exhibit optical and magnetic properties are being used for data storage and in various sensors. − In particular, nickel is suitable for enhancing near-infrared fluorescence because of its electric field has a broad range (500–800 nm) . Copper nanostructures have been used for medical application such as glucose sensing due to its high electrocatalytic properties. , These metals are relatively inexpensive, nontoxic, easily manufactured and can be stored for a longer period of time, which makes them attractive options for such applications …”

Circular Bioassay Platforms for Applications in Microwave-Accelerated Techniques

“…In the field of rapid bioassays, the concurrent use of microwave heating and plasmonic nanoparticles was demonstrated to significantly reduce assay times, which was attributed to microwave-induced temperature gradients generated between the bulk and the plasmonic nanoparticles [ 12 , 16 – 20 ]. The combined use of microwave heating and plasmonic nanoparticles was also demonstrated for rapid evaporative crystallization of amino acids and other small molecules, (i.e., metal-assisted and microwave-accelerated evaporative crystallization, MA-MAEC) [ 21 – 26 ].…”