Nanopaper as an Optical Sensing Platform

Abstract

Bacterial cellulose nanopaper (BC) is a multifunctional material known for numerous desirable properties: sustainability, biocompatibility, biodegradability, optical transparency, thermal properties, flexibility, high mechanical strength, hydrophilicity, high porosity, broad chemical-modification capabilities and high surface area. Herein, we report various nanopaper-based optical sensing platforms and describe how they can be tuned, using nanomaterials, to exhibit plasmonic or photoluminescent properties that can be exploited for sensing applications. We also describe several nanopaper configurations, including cuvettes, plates and spots that we printed or punched on BC. The platforms include a colorimetric-based sensor based on nanopaper containing embedded silver and gold nanoparticles; a photoluminescent-based sensor, comprising CdSe@ZnS quantum dots conjugated to nanopaper; and a potential up-conversion sensing platform constructed from nanopaper functionalized with NaYF4:Yb(3+)@Er(3+)&SiO2 nanoparticles. We have explored modulation of the plasmonic or photoluminescent properties of these platforms using various model biologically relevant analytes. Moreover, we prove that BC is and advantageous preconcentration platform that facilitates the analysis of small volumes of optically active materials (∼4 μL). We are confident that these platforms will pave the way to optical (bio)sensors or theranostic devices that are simple, transparent, flexible, disposable, lightweight, miniaturized and perhaps wearable.

Mechanical fabrication of high-strength and redispersible wood nanofibers from unbleached groundwood pulp

“…High-strength (Sehaqui et al 2012) transparent (Nogi et al 2009) nanopapers with embedded functionalities Morales-Narváez et al 2015) and matrix properties ) can be obtained through simple vacuum filtration. The porosities of the fabricated nanopapers can be increased by replacing the water medium with solvents that are less polar (Sehaqui et al 2011).…”

Nanomaterial-functionalized Cellulose: Design, Characterization and Analytical Applications

“…Cellulose also allows for reagents to be immobilized on the surface creating a "reagentless" sensing platform. 63 The benefits of paper as an optical sensing platform and examples of nanopaper configurations have been reviewed by Merkoci et al 64 Lateral flow devices that involve migration of reagents and analyte samples through specifically designed channels have been largely used in applications in the clinical field. Figure 6 shows an example of fabrication and operation procedure of a lateral flow device obtained by creating wax barriers on paper.…”

Paper strip-embedded graphene quantum dots: a screening device with a smartphone readout

“…These nanomaterials exhibit an excellent brightness, size-tunable photoluminescence (PL), and resistance to photobleaching 8 . Additionally, Inorganic QDs 15, 16 and QD-containing biocomposites 17 in combination with Förster resonance energy transfer (FRET) have demonstrated to be suitable for the development of paper-based assays with optical readout.…”