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Optically-assisted thermophoretic reversible assembly of colloidal particles and E. coli using graphene oxide
Jostine Puthenveetil Joby1, Suman Das2, Praveenkumar Pinapati1
1School of Physical and Applied Sciences, Goa University, Taleigao Plateau, Goa, 403206, India.
Scientific Reports
|March 8, 2022
Summary
Graphene oxide enables rapid, reversible large-scale assembly of silica beads and bacteria using light-induced thermal gradients. This optically driven thermophoresis offers new methods for material assembly and biological applications.
Area of Science:
- Materials Science
- Nanotechnology
- Biophysics
Background:
- Optically-assisted nanoparticle assembly is crucial for manipulating particles and biological entities.
- Plasmonic heating is a common method for achieving the temperature hotspots required for particle aggregation.
- An alternative approach to generating thermal gradients for non-equilibrium assembly is needed.
Purpose of the Study:
- To present a novel method for large-scale material assembly using graphene oxide's photothermal properties.
- To demonstrate the rapid and reversible assembly of silica beads via optically driven thermophoresis.
- To explore the trapping and photoablation of bacteria using this technique.
Main Methods:
- Utilizing the photothermal properties of graphene oxide (GO) microplatelets.
- Illuminating GO with a 785 nm laser at low intensities (50-100 µW/µm²).
- Observing the aggregation of 385 nm silica beads and the manipulation of E. coli bacteria.
Main Results:
- Achieved large-scale, rapid, and reversible assembly of silica beads.
- Demonstrated effective trapping and photoablation of E. coli bacteria.
- Attributed the assembly mechanism to optically driven thermophoretic forces.
Conclusions:
- Graphene oxide offers an efficient route for optically driven thermophoretic assembly.
- This method is promising for studying non-equilibrium processes and material assembly.
- Potential applications include rapid concentration for spectroscopy and biological manipulation.
