Calligraphed Selective Plasmonic Arrays on Paper Platforms for Complementary Dual Optical "ON/OFF Switch" Sensing

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2020-05, Vol.10 (6), p.1025
• Main Authors: Susu, Laurentiu, Campu, Andreea, Astilean, Simion, Focsan, Monica
• Format: Article
• Language: English
• Subjects: MEF; multiplexed paper substrate; nanoparticles; ON/OFF switch detection; plasmonic lines; SERS
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano10061025

Designing innovative (nano)detection platforms, respecting their low-cost and fabrication simplicity, capable to chemically detect multiple target analytes by employing the same engineered device, is still a great challenge in the multiplexed biosensor development. In this scientific context, in the current manuscript, we exploit the low-cost plasmonic calligraphy as a versatile approach to directly draw continuous plasmonic lines on Whatman paper using a regular ballpoint pen successively filled with two different anisotropic nanoparticles shapes (gold bipyramids-AuBPs and gold nanorods-AuNRs) as colloidal inks. After the efficient immobilization of the positively-charged AuBPs and AuNRs onto the paper fibres, proved by Scanning Electron Microscopy (SEM) investigations, the specificity of our as-calligraphed-paper platform is ensured by coating the selected lines with a thin layer of anionic poly(styrene sulfonate) polyelectrolyte, creating, consequently, a well-defined plasmonic array of charge-selective regions. Finally, the functionality of the well-isolated and as-miniaturized active plasmonic array is, subsequently, tested using the anionic Rose-Bengal and cationic Rhodamine 6G target analytes and proved by complementary dual optical "ON/OFF Switch" sensing (i.e. Surface-enhanced Raman Scattering sensing/metal-enhanced fluorescence sensing) onto the same plasmonic line, developing thus a simple multiplexed plasmonic array platform, which could further facilitate the well-desired biomarker detection in complex mixtures.