Large-Area Low-Cost Flexible Plastic Nanohole Arrays for Integrated Bio-Chemical Sensing

Abstract

Detection of plasmonic resonance peak shifts of nano-structured metamaterials is a promising method for sensing bio-chemical binding events. Although the concept is widely demonstrated in the laboratory environment using surface nanostructures machined at low-throughput and high-costs, practical solutions for high-volume production of an integrated sensing device are very limited. We present a concept of an integrated architecture that combines a thin layer of plasmonic nanohole sensing arrays, organic light-emitting diode illumination source, and microfluidic chip, for point-of-care, field, or lab applications. We discuss the fabrication of the sensor components. In particular, we present the improved fabrication of master nano-structure replication stamps, and demonstrate outstanding results for producing singular sheets or scale up to roll-toroll embossing of nanohole arrays on a 2000 ft production roll. We further demonstrate that nanohole arrays embossed on flexible polyethylene terephthalate plastic sheets, when coated with 100 nm thin Au metal film, are capable of generating average plasmonic resonance shifts of 180 nm refractive index unit. Hence, we report the extraordinary transmission and plasmonic resonance shifts of nanohole arrays fabricated on roll-to-roll plastic sheets for the very first time. Our results show that the embossed nano-structures on plastic are suitable as sensor elements in our proposed integrated sensor architecture, and a promising technology for low-cost disposable applications.

Gold Elliptic Nanocavity Array Biosensor With High Refractive Index Sensitivity Based on Two-Photon Nanolithography

“…The S of this chip is 562 nm/RIU. It's higher than that of other previously reported nanoperiod arrays with similar period and measurement wavelength regime [17], [30]. Comparing S of the experiment to the simulation, experiment determined S is about 30 nm/RIU less than that of the simulation.…”

“…Although all of the nanostructures can be used to fabricate refractive index sensors, the reflective index sensitivity of the nanorods are about 100 $ 300 nm/RIU which is smaller than the nanoholes reflective index sensitivity from 400 $ 700 nm/RIU [17], [25]- [27]. The high reflective index sensitivity of the nanoholes is because many modes can be excited and couple each other to generate the Fano resonances.…”

“…There are three common types of fabrication technologies: 1) self-assembly technology (e.g., colloidal nucleation and growth [15] and nanosphere lithography [16]) and 2) replication technology (e.g., nanoimprint [17]), 3) pattern direct writing technology (e.g. electron beam lithography (EBL) [18], focused ion beam (FIB) [19], and two-photon nanolithography (TPNL) [20]).…”

Flexible Plasmonic Sensors

“…These plasmonic nano-structures have traditionally been fabricated through standard semiconductor fabrication techniques, which limited such plasmonic designs to mainly rigid Si or SiO 2 substrates [17]. Moreover, these fabrication techniques are generally costly, requiring a clean room with expensive, dedicated equipment and are often inherently low-throughput, by and large limiting their fabrication and use to resource rich laboratories [14], [18]–[20]. …”

“…Additionally, with the exclusion of colloidal lithography, these emerging low-cost high-throughput techniques allow for a diverse array of nanostructures to be packed into a small sensor area. This type of sensor design is therefore capable of multiplexed or multi-channel detection which can lead to higher accuracy and greater capacity for detecting a panel of target bio-chemicals [20], [25]. These flexible substrates have also been proven to support a wide range of complex nano-structures such as nano-hole arrays, nano-dome arrays, nano-pillars, and bow-tie structures, without significant loss in fidelity, therefore bringing highly sensitive adsorption measurements to an ensemble of novel applications [20], [26]–[31].…”