(400f) The Fabrication of Capillary Electrophoresis Microfluidic Chips with Metal Oxide Nanoparticles to Control Optical Properties

Microfluidic chips are commonly utilized to study the fluid flow through micron sized channels. These chips can be used in a variety of applications in the medical, environmental, and engineering fields. Typically, optical detection techniques are employed to verify performance and quantitative results, creating challenges in chip fabrication.

Hummingbird Nano (HBN) Inc. has developed a rapid and sustainable method for fabricating capillary electrophoresis microfluidic chips by molding channels using ferrofluid controlled by magnetic fields. The channels are molded in a highly functionalized, viscous monomer, dipentaerythritol pentaacrylate (SR-399). Polymerization through the application of UV light will create a solid polymer matrix surrounding the ferrofluid. The ferrofluid is then recovered to be reused, and micron sized channels are successfully embedded within the polymer.

Optical sensing devices can then be placed directly adjacent to the material at the point of manufacture. To avoid detection losses, the refractive index of the polymer can be matched to that of the fiber optic cable. Inorganic nanoparticle crystallites with known refractive indices and well-defined size distributions are used to control the refractive index of the nanocomposite chip material. Metal oxide nanoparticles can be synthesized with particle dimensions small enough to efficiently reduce light scattering, maintaining the monomer’s transparent properties.

In collaboration with HBN, funded by NSF SBIR, a nanocomposite comprised of SR-399 and metal oxide nanoparticles are developed with the appropriate refractive index and material properties suitable for the manufacture of capillary electrophoresis microfluidic chips. The nanoparticles are synthesized, characterized, and then functionalized for dispersion in the monomer prior to polymerization. Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray Spectroscopy (EDS) are utilized to determine size, morphology, and composition of the nanoparticles.