New Tool For Rapid And Accurate Detection Of Interleukin-2 And Soluble Interleukin-2 Receptor A In Cancer Diagnosis Using A Bioresponsive Microgel And Multivalent Protein Binding

Interleukin-2 (IL-2) and its a receptor in soluble form (sIL-2R alpha) are considered biomarkers for cancers and immune-related diseases. Enzyme-linked immunosorbent assay is the most common method used to evaluate biomarkers in clinical practice; it is precise but time-consuming and involves complicated procedures. Here, we have developed a rapid yet accurate modality for cancer diagnosis that enables on-site evaluation of cancer markers, that is, IL-2 and sIL-2R alpha, without complicated pretreatment of cancer patient-derived blood samples. Surface plasmon resonance and bioresponsive microgels conjugated with IL-2 receptors, that is, IL-2R beta and IL-2R gamma, were utilized to measure IL-2 and sIL-2R alpha levels via multivalent protein binding (MPB) between the ligands and their receptors. Our results showed that this novel method enables us to perform cancer diagnosis with a 1000-fold dilution of serum in 10 min. The advantage of MPB-based cancer diagnosis originates from its great selectivity for a target molecule and tolerance to a myriad of nonspecific substances in serum, which allows on-site clinical evaluation. Importantly, our finding implies that MPB-based cancer diagnosis provides a new paradigm not only for improving cancer treatment but also for evaluating a target molecule in unpurified and complex solutions such as blood.