LAUSR

&NA; An approach similar to the enzyme‐linked immunosorbent assay (ELISA), with the advantage of saving time and effort but exhibiting high performance, was developed using orientation‐directed half‐part antibodies immobilized on CdSe/ZnS quantum dots. ELISA is a widely accepted assay used to detect the presence of a target substance. However, it takes time to quantify the target with specificity and sensitivity owing to signal amplification. In this study, CdSe/ZnS quantum dots are introduced as bright and photobleaching‐tolerant fluorescent materials. Since hydrophilic surface coating of quantum dots rendered biocompatibility and functional groups for chemical reactions, the quantum dots were modified with half‐sized antibodies after partial reduction. The half‐sized antibody could be bound to a quantum dot through a unique thiol site to properly display the recognition domain for the core process of ELISA, which is an antigen‐antibody interaction. The reducing conditions were investigated to generate efficient conjugates of quantum dots and half‐sized antibodies. This was applied to IL‐6 detection, as the quantification of IL‐6 is significant owing to its close relationships with various biomedical phenomena that cause different diseases. An ELISA‐like assay with CdSe/ZnS quantum dot institution (QLISA; Quantum dot‐linked immunosorbent assay) was developed to detect 0.05 ng/mL IL‐6, which makes it sufficiently sensitive as an immunosorbent assay. Graphical abstract Figure. No caption available. HighlightsAntibody‐attached quantum dots were used to establish an ELISA‐like assay, QLISA.Antibody was reduced to expose thiol groups for directed linkage to quantum dots.Efficiently labeled antibodies with bright quantum dots could amplify QLISA signal.QLISA was proven to be a general time‐ and effort‐saving assay.