We employ the inexpensive, biocompatible and safe halloysite nanotubes (HNT) into self-assembly inside microhannels. HNT is a naturally occurring alumosilicate clay mineral that has a rolled structure with 50 nm external diameter. The tubes have a lumen with an inner diameter of 10-15nm and a length of tubes from 400-1500 nm. The micro-patterns are formed when a dispersion of halloysite orders itself like a nematic liquid crystal with the resultant pattern fixed by drying. Halloysites modified with the negative polyelectrolyte such as polystyrene sulfonate (PSS) have a higher negative charge and contribute to the liquid crystal behavior of halloysite dispersions. PSS modified HNTs in an aqueous solution will, upon drying, remain fixed on the sides of the microchannel in concentric rings. These arrays of nanotubes can be tuned with concentration and temperature gradients.<br/>Microfluidic channels are useful for examining forces that act on the nanoscale and are very important to space research on cell capturing. The microchannel devices are small, inexpensive and easy to make with wide range of possibility for size and shape. We make microchannels with oriented halloysite arrays within them, which we can then control for fluidic flow and selective macromolecules adsorption. This approach can be made more permanent by the “firing” of the microchannel whereby the HNTs are pulled into the surface of the glass and permanently arranged as a matrix. These microfluidic devices will be useful for cell capture and tunability of physical properties of the microchannels.

Self-assembly of halloysite nanotubes in microchannels for functionalizing microfluidic devices to capture cells

255th National Meeting (2018)

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