Handheld high-throughput plasmonic biosensor using computational on-chip imaging

Abstract

We demonstrate a handheld on-chip biosensing technology that employs plasmonic microarrays coupled with a lens-free computational imaging system towards multiplexed and high-throughput screening of biomolecular interactions for point-of-care applications and resource-limited settings. This lightweight and field-portable biosensing device, weighing 60 g and 7.5 cm tall, utilizes a compact optoelectronic sensor array to record the diffraction patterns of plasmonic nanostructures under uniform illumination by a single-light emitting diode tuned to the plasmonic mode of the nanoapertures. Employing a sensitive plasmonic array design that is combined with lens-free computational imaging, we demonstrate label-free and quantitative detection of biomolecules with a protein layer thickness down to 3 nm. Integrating large-scale plasmonic microarrays, our on-chip imaging platform enables simultaneous detection of protein mono-and bilayers on the same platform over a wide range of biomolecule concentrations. In this handheld device, we also employ an iterative phase retrieval-based image reconstruction method, which offers the ability to digitally image a highly multiplexed array of sensors on the same plasmonic chip, making this approach especially suitable for high-throughput diagnostic applications in field settings.

Mapping the electromagnetic field confinement in the gap of germanium nanoantennas with plasma wavelength of 4.5 micrometers

“…The dielectric function of the 250 nm thick germanium film is determined, and bow-tie antennas are designed, fabricated, and embedded in a polymer. By using a near-field photoexpansion mapping technique at k ¼ 5.8 lm, we demonstrate the existence in the antenna gap of an electromagnetic energy density hotspot of diameter below 100 nm and confinement volume 10 5 times smaller than k Plasmonic nanoantenna designs are quickly evolving in the direction of practical molecular sensing applications 1 as their wavelength range is being extended from the visible towards the mid-infrared 2,3 (IR), where molecules indeed display unique spectral fingerprints (IR wavelengths k between 2.5 lm and 25 lm). The two main features of plasmonic nanoantennas are electromagnetic field enhancement and confinement in subwavelength regions.…”

Biosensors in Antimicrobial Drug Discovery: Since Biology until Screening Platforms

“…For that reason, the development of new multiplexing biosensors with multi-array in screening platforms as optofluidics and various biomarkers may constitute an advance in solving this problem [136,137]. …”

Localized fields, global impact: Industrial applications of resonant plasmonic materials

“…56 Most recently, plasmonic sensing has achieved antibodies. 57 The hand-held sensor could be integrated with cell phones, as illustrated in Figure 4b , providing high-throughput and low-cost refractive-index sensing of bacteria and proteins in blood or saliva to benefi t medical diagnosis in underdeveloped areas. 58 Rather than relying on specifi c binding interactions (e.g., with antibodies), chemical identifi cation can also be achieved using mid-infrared molecular vibrational resonances, which serve as "molecular fi ngerprints."…”