Rapid ELISA Using a Film-Stack Reaction Field with Micropillar Arrays

A film-stack reaction field with a micropillar array using a motor stirrer was developed for the high sensitivity and rapid enzyme-linked immunosorbent assay (ELISA) reaction. The effects of the incubation time of a protein (30 s, 5 min, and 10 min) on the fluorescence intensity in ELISAs were investigated using a reaction field with different micropillar array dimensions (5-µm, 10-µm and 50-µm gaps between the micropillars). The difference in fluorescence intensity between the well with the reaction field of 50-µm gap for the incubation time of 30 s and the well without the reaction field with for incubation time of 10 min was 6%. The trend of the fluorescence intensity in the gap between the micro pillars in the film-stack reaction field was different between the short incubation time and the long incubation time. The theoretical analysis of the physical parameters related with the biomolecule transport indicated that the reaction efficiency defined in this study was the dominant factor determining the fluorescence intensity for the short incubation time, whereas the volumetric rate of the circulating flow through the space between films and the specific surface area were the dominant factors for the long incubation time.

Stereolithography-Based 3D Printed "Pillar Plates" that Minimizes Fluid Transfers During Enzyme Linked Immunosorbent Assays

Enzyme linked immunosorbent assay (ELISA) is one of the most popular and indispensable tools in molecular biology. Despite numerous advances in ELISA methods that markedly improve the sensitivity and throughput of detection, a hallmark of all ELISA continues to be repeated pipetting of fluids that is not only cumbersome but can easily introduce errors or contaminations. Robotics, despite obvious advantages, remains expensive. Here, we designed and produced cheap "pillar plates" using stereolithography-based 3D printing that can be readily inserted into conventional 96- and 384- well plates and serve as the substrate for ELISA. We demonstrate that ELISA using these "pillar plates" affords comparable specificity and sensitivity of detection of serum antibodies to traditional sandwich ELISA, while markedly reducing the time and efforts associated with fluid transfer. These results underscore "pillar plates" as an attractive platform for rapid yet robotics-free ELISA.

High sensitivity, high surface area Enzyme-linked Immunosorbent Assay (ELISA)

BACKGROUND

Enzyme-linked immunosorbent assays (ELISA) are considered the gold standard in the demonstration of various immunological reactions with an application in the detection of infectious diseases such as during outbreaks or in patient care.

OBJECTIVE

This study aimed to produce an ELISA-based diagnostic with an increased sensitivity of detection compared to the standard 96-well method in the immunologic diagnosis of infectious diseases.

METHODS

A '3DStack' was developed using readily available, low cost fabrication technologies namely nanoimprinting and press stamping with an increased surface area of 4 to 6 times more compared to 96-well plates. This was achieved by stacking multiple nanoimprinted polymer sheets. The flow of analytes between the sheets was enhanced by rotating the 3DStack and confirmed by Finite-Element (FE) simulation. An Immunoglobulin G (IgG) ELISA for the detection of antibodies in human serum raised against Rubella virus was performed for validation.

RESULTS

An improved sensitivity of up to 1.9 folds higher was observed using the 3DStack compared to the standard method.

CONCLUSIONS

The increased surface area of the 3DStack developed using nanoimprinting and press stamping technologies, and the flow pattern between sheets generated by rotating the 3DStack were potential contributors to a more sensitive ELISA-based diagnostic device.

Application of 3D Printing Technology in Increasing the Diagnostic Performance of Enzyme-Linked Immunosorbent Assay (ELISA) for Infectious Diseases

Enzyme-linked Immunosorbent Assay (ELISA)-based diagnosis is the mainstay for measuring antibody response in infectious diseases and to support pathogen identification of potential use in infectious disease outbreaks and clinical care of individual patients. The development of laboratory diagnostics using readily available 3D printing technologies provides a timely opportunity for further expansion of this technology into immunodetection systems. Utilizing available 3D printing platforms, a ‘3D well’ was designed and developed to have an increased surface area compared to those of 96-well plates. The ease and rapidity of the development of the 3D well prototype provided an opportunity for its rapid validation through the diagnostic performance of ELISA in infectious disease without modifying current laboratory practices for ELISA. The improved sensitivity of the 3D well of up to 2.25-fold higher compared to the 96-well ELISA provides a potential for the expansion of this technology towards miniaturization and Lab-On-a-Chip platforms to reduce time, volume of reagents and samples needed for such assays in the laboratory diagnosis of infectious and other diseases including applications in other disciplines.

High-throughput generation of micropatterns of dye-containing capsules embedded in transparent elastomeric monoliths by inkjet printing

We report the high-throughput fabrication of transparent elastomeric monoliths containing customized micropatterns of microcapsules, which might be used as highly flexible identity tags, sensor elements, and photochromic, photonic, or phononic systems. High-throughput replication molding of microsphere monolayers used as sacrificial primary templates via negative secondary replicas and positive tertiary replicas yielded elastomeric specimens containing dense hexagonal arrays of open spherical microcavities. In a subsequent inkjet printing step, some of the open-spherical microcavities were filled with functional materials such as dyes. The subsequent addition of an elastomeric cover layer led to encapsulation of the dyes trapped in the printed microcavities, while empty microcavities were filled with elastomer and vanished.