3c further displays the fluorescence image of the QDs nanobeads adsorbed magnetic beads, validating the feasibility of the method proposed. desire for bioimaging and biosensing, and a significant progress has been made thanks to the sophisticated surface covering technology developed especially for CdSe@ZnS core-shell QDs [[1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12]]. However, to the best of our knowledge, most of previous reported QDs-based fluorescence methods for bioassay usually suffer from low sensitivity compared to that of medical center ones, such as chemical luminescence immunoassay (CLIA) [13], digital enzyme-linked immunosorbent assay (digital ELISA) [7], and time-resolved fluorescence immunoassay (TRFIA) [14], among which the sensitivity for protein detection could reach subfemtomolar concentration. This partially could be ascribed to the difficulty on the synthesis of covering reagents that can render QDs biocompatible and fluorescence-stable over a long period of time [[15],[16],[17]]. In addition, the increased hydrodynamic size and decreased fluorescence yield brought by QDs phase transfer further make their initial superiority less obvious, as compared to their counterparts. Therefore, how to overcome these defects plays a vital role in development of QDs-based bioassay technology with ultrahigh sensitivity, which could contribute to the medical center application of QDs technology in bioassay. Gao et al. recently reported work developed a QDs based fluorescence bioassay capable of dramatically improving the sensitivity of virtually all common biodetection techniques including ELISA, lateral circulation Digoxigenin strips and suspension microarray by approximately three orders of magnitude [5]. The mechanism behind involved the densely adsorption of individual PEGNH2capped QDs on the surface of HRP-catalysed polydopamine deposited on secondary antibody and nearby proteins, leading to huge fluorescence transmission amplification. Nonetheless, the use of oxidant H2O2at high concentration and the fresh preparation requirement of Palmitoyl Pentapeptide deposition solution are the innegligible drawbacks in practical application. QDs encapsulation in silica nanobeads is an alternate widely adopted as transmission amplification materials for the development of bioassay with improved sensitivity [[18],[19],[20],[21],[22],[23],[24]]. Typically, the synthesis Digoxigenin fluorescence nanobeads entails the immobilization of QDs on the surface of colloidal silica recognized by amino-group mediated electrostatic conversation or thiol-group driven coordination, followed by silica shell covering for the purpose of fluorescence stabilization and functionalization. To data, nonporous [[18],[19],[20],[21],[22]] and dendritic silica [23,24] are the chief themes for QDs assembly, among which dendritic silica featured with ultralarge pore channels and highly accessible inner surface exhibits obvious superiority for QDs loading and application in sensitive bioassay as compared with its counterparts. In addition, polystyrene (PS) bead, due to its sophisticated synthesis technique, is the core material commonly served as the suspension carrier for the immobilization of capture antibody in the above mentioned techniques [7]. Most importantly, as compared with silica, Coefficient of Variance value of monodisperse PS beads could reach 3% with good reproducibility, much less than that of commercial silica particles (typically 1015%), and the large quantity of carboxyl group on their surface could be precisely controlled by adjusting Digoxigenin the ratios of reactants. However, to the best of our knowledge, PS beads-based template for development of QDs nanobeads as labeling material has not been reported. Herein, highly fluorescent 200 nm QDs nanobead was fabricated using commercially-available PS beads as absorbent host and CdSe@ZnS QDs nanoparticles, followed by a silica shell covering for protection and further biosensing. The fluorescence properties of this nanobead was characterized and compared with commercially available fluoro-max fluorescent beads with europium chelate, and finally its overall performance on sensitive detection of H5N1 computer virus and SARS-CoV-2 antibody as fluorescence.