Highly multiplexed point of care tests could improve diagnostic accuracy and differential diagnostic capacity in for instance emergency medicine and low resource environments. Available technology platforms for POC biomarker detection are typically simplex or low-plexed, whereas common lab-based microarray systems allow for the simultaneous detection of thousands of DNA or protein biomarkers. In this study, we demonstrate a novel suspension particle array platform that utilizes 900 μm bricks for POC amenable colorimetric biomarker detection with an encoding capacity of over two million. Due to the mm-scale size, both the lithographic codes and colorimetric signals of individual particles can be visualized using a consumer grade office flatbed scanner, with a potential for simultaneous imaging of around 19 000 particles per scan. The analytical sensitivity of the assay was determined to be 4 ng ml using an antibody model system. As a proof of concept, autoantibodies toward anoctamin 2 were detected in order to discriminate between multiple sclerosis plasma samples and healthy controls with p < 0.0001 and an inter-assay % CV of 9.44%.

Proteins secreted by skin have great potential as biomarkers for interpreting skin conditions. However, inconvenience in handling and bulky size of existing methods are existing limitations. Here, we describe a thumbnail sized patch with the array of microdisks which captures multiple proteins from the skin surface. Microdisks with antibody on the surface enable multiplexed immunoassay. By self-assembly, microdisks are placed into 2-dimensional arrays on adhesive tape. The proposed Enzyme-Linked Immunospot array on a Patch shows sufficient sensitivity for IL-1a, IL1RA, IL-17A, IFN-g, and TNF-a, while IL-6 and IL-1b are non-detectable in some cases. As demonstrations, we quantified cytokines from different skin regions and volunteers in a high-spatial-resolution.

Barcoded planar microparticles are suitable for developing cost-efficient multiplexed assays. But robustness and efficiency of the readout process still needs improvement. Here, we designed a one-step microparticle assembling chip that...