Novel nanoplasmonic biosensor integrated in a microfluidic channel

Abstract

An important motivation of the actual biosensor research is to develop a multiplexed sensing platform of high sensitivity fabricated with large-scale and low-cost technologies for applications such as diagnosis and monitoring of diseases, drug discovery and environmental control. Biosensors based on localized plasmon resonance (LSPR) have demonstrated to be a novel and effective platform for quantitative detection of biological and chemical analytes. Here, we describe a novel label-free nanobiosensor consisting of an array of closely spaced, vertical, elastomeric nanopillars capped with plasmonic gold nanodisks in a SU-8 channel. The principle is based on the refractive index sensing using the LSPR of gold nanodisks. The fabrication of the nanobiosensor is based on replica molding technique and gold nanodisks are incorporated on the polymer structures by e-beam evaporation. In this work, we provide the strategies for controlling the silicon nanostructure replication using thermal polymers and photopolymers with different Young´s modulus, in order to minimize the common distortions in the process and to obtain a reliable replica of the Si master. The master mold of the biosensor consists of a hexagonal array of silicon nanopillars, whose diameter is ~200 nm, and whose height can range from 250 nm to 1.300 µm, separated 400 nm from the center to center, integrated in a SU-8 microfluidic channel.

Building of a flexible microfluidic plasmo-nanomechanical biosensor for live cell analysis

“…Characterization of the plasmo-nanomechanical biosensor PDMS molds of nanoholes were fabricated from silicon masters molds according to the controlled procedure described in 23 . Fig.…”

“…The plasmo-nanomechanical biosensor design consists of an hexagonal array of closely spaced, vertical, elastomeric nanopillars capped with plasmonic gold nanodisks embedded in a microfluidic channel. The fabrication of the biosensor includes the following steps: 1) fabrication of a Si master mold, 2) production of a patterned PDMS stamp from the master mold, 3) generation of a polymer replica of the original template, 4) evaporation of plasmonic gold nanodisks on the polymer nanopillars by e-beam evaporation 22,23 and 5) bonding of the biosensor, as shown in Fig. 1.…”

“…The methodology described in 23 was used to create a 1 mm thickness polydimethylsiloxane (PDMS) replica of the silicon master mold (Fig. 1b).…”

“…The UV curable polymer EPO-TEK OG142-87 and thermal EPO-TEK 310M were used to produce the replica of the silicon nanopillar arrays integrated in the SU-8 microchannel. The process was based on a methodology described in 23 . For the UV curable polymer, 1 g of polymer was poured on the PDMS and placed in a vacuum desiccator in order to remove air bubbles and fill the nanoholes.…”

“…The fabrication of the biosensor is based on a replica molding technique that we reported previously. 22,23 The elastomeric nanopillars are designed to mimic soft or rigid tissues using two new polymer materials (EPOTECK OG142 and 310M). The biosensor combines the mechanical flexibility of polymer nanopillars with the optical properties of plasmonic gold nanodisks that exhibit a LSPR response.…”