A multiwell plasmonic reader was designed and validated for higher throughput analysis of biological interactions with a platform of the same size as standard 96-well plates. While the plasmonic sensor can be read with standard 96-well plate readers, a custom 96-well plate reader was designed to analyze nanohole arrays at high incident angles required for higher sensitivity. Gold nanohole arrays were manufactured on a 4 in. glass wafer using a photolithographic process. In comparison to single channel measurements with nanohole arrays fabricated with nanosphere lithography, the nanohole array sensors greatly enhanced the signal-to-noise ratio of the plasmonic signal and precision of the measurements with the multiwell plate system. As proof of concept, the detection of IgG in the low nanomolar range was achieved with the multiwell plate reader. The multiwell plasmonic plate reader was also applied to the screening of several prostate specific (PSA) antibodies for secondary detection of PSA and for the analysis of an anticancer drug through a competitive assay between methotrexate (MTX) and folic acid Au nanoparticle (FaNP) for human dihydrofolate reductase (hDHFR). The multiwell plasmonic reader based on nanohole array technology offers the rapid, versatile, sensitive, and simple high throughput detection of biomolecules.

A multi-channel system combining fluidics and micropatterned plasmonic materials with wavelength interrogation surface plasmon resonance (SPR) and fluorescence detection was integrated from the combination of a small and motorized fluorescence microscope mounted on a portable 4-channel SPR instrument. The SPR and fluorescent measurements were performed based on the same detection area in a multi-channel fluidic, with a sensing scheme for prostate-specific antigen (PSA) consisting of a sandwich assay with a capture anti-PSA immobilized onto the SPR sensor and a detection anti-PSA modified with horseradish peroxidase (HRP). In this dual-detection instrument, fluorescence was measured from the solution side of the micropatterned gold film, while the interface between the glass prism and the gold film served to interrogate the SPR response. The SPR sensors were comprised of microhole arrays fabricated by photolithography to enhance the instrumental response for PSA detection by approximately a factor of 2 to 3 and they were coated with a self-assembled monolayer of a peptide (3-MPA-HHHDD-OH) to minimize nonspecific adsorption. PSA was successfully detected at clinical concentrations from 10 pM to 50 nM with this integrated system in a single assay lasting 12 minutes, almost centering on the desired range for PSA diagnostic tests (>4 ng mL(-1) or >150 pM). The combination of two robust techniques in a single chip and instrument has led to a simple and effective assay that can be carried out on a small and portable instrument providing rapid biodetection of an important cancer biomarker with a dynamic range of nearly 4 orders of magnitude in the clinical range.

The presence of microhole arrays in thin Au films is suited for the excitation of localized and propagating surface plasmon (SP) modes. Conditions can be established to excite a resonance between the localized and propagating SP modes, which further enhanced the local electromagnetic (EM) field. The co-excitation of localized and propagating SP modes depends on the angle of incidence (θ(exc)) and refractive index of the solution interrogated. As a consequence of the enhanced EM field, enhanced sensitivity and an improved response for binding events by about a factor of 3 to 5 was observed with SPR sensors in the Kretschmann configuration for a set of experimental conditions (λ(SPR), θ(exc), and η). Thus, microhole arrays can improve sensing applications of SPR based on classical prism-based instrumentation and are suited for SP-coupled spectroscopic techniques.

Integrating a SERS immunoassay on a plasmonic "patch clamp" nanopipette enabled nanobiosensing for the detection of IgG. A SERS response was obtained using a sandwich assay benefiting from plasmon coupling between a capture Au nanoparticle (AuNP) on a nanotip and a second AuNP modified with a Raman active reporter and an antibody selective for IgG. The impact of nanoparticle shape and surface coverage was investigated alongside the choice of Raman active reporter, deposition pH, and plasmonic coupling, in an attempt to fully understand the plasmonic properties of nanopipettes and to optimize the nanobiosensor for the detection of IgG. These probes will find applications in various fields due to their nanoscale size leading to the possibility of spatially and temporally addressing their location near cells to monitor secretion of biomolecules.