22:T47c,Surface proteins of cells are generally recognized through receptor-ligand interactions (RLIs) in disease diagnosis, but their nonuniform spatial distribution and higher-order structure lead to low binding affinity. Constructing nanotopologies that match the spatial distribution of membrane proteins to improve the binding affinity remains a challenge. Inspired by the multiantigen recognition of immune synapses, we developed modular DNA-origami-based nanoarrays with multivalent aptamers. By adjusting the valency and interspacing of the aptamers, we constructed specific nanotopology to match the spatial distribution of target protein clusters and avoid potential steric hindrance. We found that the nanoarrays significantly enhanced the binding affinity of target cells and synergistically recognized low-affinity antigen-specific cells. In addition, DNA nanoarrays used for the clinical detection of circulating tumor cells successfully verified their precise recognition ability and high-affinity RLIs. Such nanoarrays will further promote the potential application of DNA materials in clinical detection and even cell membrane engineering.23:T47a,Triggering receptors expressed on myeloid cells 2 (TREM2) is a novel cell surface receptor and functions as an immunomodulatory receptor in infectious diseases. In this study, we investigated the function and regulatory mechanism of TREM2 in Pseudomonas aeruginosa (P. aeruginosa) keratitis. We found that P. aeruginosa keratitis was more severe in Trem2^-/- versus wild type C57BL/6 mice as indicated by the increased clinical scores, bacterial load, and cornea pathology. The exacerbated disease progression caused by TREM2 deficiency was associated with boosted activation of caspase-1 and subsequent pyroptosis as well as increased expression of IL-1β. In addition, blockage of pyroptosis by caspase-1 inhibitor not only recovered the severe cornea pathology developed in Trem2^-/- mice but also restored the P. aeruginosa clearance suppressed by TREM2 deficiency. Our study demonstrated that TREM2 promotes host resistance against P. aeruginosa keratitis by inhibiting caspase-1-dependent pyroptosis, which provides new insights of TREM2-mediated anti-bacterial immunity.24:T402,Serological assay for coronavirus 2019 (COVID-19) patients including asymptomatic cases can inform on disease progression and prognosis. A detection method taking into account multiplex, high sensitivity, and a wider detection range will help to identify and treat COVID-19. Here we integrated color-size dual-encoded beads and rolling circle amplification (RCA) into a bead-based fluorescence immunoassay implemented in a size sorting chip to achieve high-throughput and sensitive detection. We used the assay for quantifying COVID-19 antibodies against spike S1, nucleocapsid, the receptor binding domain antigens. It also detected inflammatory biomarkers including interleukin-6, interleukin-1β, procalcitonin, C-reactive protein whose concentrations range from pg mL^-1 to μg mL^-1 . Use of different size beads integrating with RCA results in a tunable detection range. The assay can be readily modified to simultaneously measure more COVID-19 serological molecules differing by orders of magnitude.

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