SPR Biosensor Based on Polymer Multi-Mode Optical Waveguide and Nanoparticle Signal Enhancement

• Main Authors: Johanna-Gabriela Walter, Alina Eilers, Lourdes Shanika Malindi Alwis, Bernhard Wilhelm Roth, Kort Bremer
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Sensors
• Subjects: surface plasmon resonance (SPR); sensor; planar-optical; multi-mode; waveguide; biosensor
• Online Access: https://www.mdpi.com/1424-8220/20/10/2889

We present a surface plasmon resonance (SPR) biosensor that is based on a planar-optical multi-mode (MM) polymer waveguide structure applied for the detection of biomolecules in the lower nano-molar (nM) range. The basic sensor shows a sensitivity of 608.6 nm/RIU when exposed to refractive index changes with a measurement resolution of 4.3 × 10⁻³ RIU. By combining the SPR sensor with an aptamer-functionalized, gold-nanoparticle (AuNP)-enhanced sandwich assay, the detection of C-reactive protein (CRP) in a buffer solution was achieved with a response of 0.118 nm/nM. Due to the multi-mode polymer waveguide structure and the simple concept, the reported biosensor is well suited for low-cost disposable lab-on-a-chip applications and can be used with rather simple and economic devices. In particular, the sensor offers the potential for fast and multiplexed detection of several biomarkers on a single integrated platform.