Fast, cheap and reliable detection of biomolecules is of increasing need in various fields, including early diagnosis of cancer and infectious diseases [1,2]. Applications often concern the analysis of biomarkers present in... [ view full abstract ]
Fast, cheap and reliable detection of biomolecules is of increasing need in various fields, including early diagnosis of cancer and infectious diseases [1,2]. Applications often concern the analysis of biomarkers present in bodily fluids at very low concentrations.
In order to sensitively detect trace amounts of biomarkers by the use of fluorescence assays, the plasmonic amplification of the fluorescence intensity associated with a specific capture of the target analyte has been pursued [3]. The highly increased field strength accompanied with the resonant excitation of surface plasmons at the adsorption and emission wavelengths of fluorophore labels allows enhancing the detected fluorescence intensity by a factor of 103 if the binding occurs at the plasmonic hotspot [4].
We report a strategy to selectively functionalize metallic nanostructures composed of gold and oxide features utilizing a responsive hydrogel binding matrix. A layer-by-layer (LBL) approach is used to attach a three dimensional pNIPAAm-based photo-cross-linkable hydrogel at the plasmonic hotspot. This hydrogel can be post-modified with ligand molecules to selectively capture the target analyte. After the analyte capture, the collapse of the hydrogel pulls the captured analyte towards the plasmonic hotspot where the sensitivity of detection can be most efficiently plasmonically enhanced.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 633937, project ULTRAPLACAD.
References:
[1] Peeling, R. W., and D. Mabey. "Point‐of‐care tests for diagnosing infections in the developing world." Clinical microbiology and infection 16.8 (2010): 1062-1069.
[2] Tothill, Ibtisam E. "Biosensors for cancer markers diagnosis." Seminars in cell & developmental biology. Vol. 20. No. 1. Academic Press, 2009.
[3] Bauch, Martin, et al. "Plasmon-enhanced fluorescence biosensors: a review." Plasmonics 9.4 (2014): 781-799.
[4] Kinkhabwala A, Yu ZF, Fan SH, Avlasevich Y, Mullen K, Moerner WE (2009) Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna. Nat Photonics 3(11):654– 657
