Microfluidic Synthesis Of Biocarriers And Applications

Microfluidics is a science and technology involving physics, chemistry, engineering and biology that deals with the precise control and manipulation of small quantities of fluids constrained in microchannels. It has achieved rapid development in the fields of micro-mixing, micro-separation, micro-reaction and micro-detection. Owing to precise control of the flow in microscale, microfluidics has highlighted the incomparable superiority to traditional preparation technology in fabrication of functional and structural microcarriers. It is expected that the achieved microcarriers have significant potential applications in gene sequencing, multiplex bioanalysis, drug release and screening, cell culture and other fields, and will promote the development of the biomedicine technique. Therefore, we focused on fabrication of functional biocarriers by microfluidics and developing their applications in biomedicine. The detail works are as follow:(1) Barcode beads with quantum dot (QD)-photonic crystal (PC) joint spectral identifies were developed. These barcode beads were simply prepared by in-situ polymerization of CdTe QDs-contained acrylamide pre-gel in the colloidal photonic crystal beads (PCBs). The PCBs were derived from colloidal droplet templates which were created on a glass microfluidic device. By encapsulating different wavelength-and-intensity QDs into the PCBs with various-reflection spectra, thousands of available barcode beads could be obtained. Spectroscopic measurements and DNA hybridization experiments indicate that the encoded beads are highly practical for multiplex coding bioassays.(2) Non-spherical colloidal crystal particles were fabricated by a new microfluidic approach. The microfluidic devices were composed of a cylindrical injection capillary and collection capillaries with available size and shape. Based on these devices, the monodisperse droplet templates with a series of geometries could appear and flow through the collection capillaries. As the dispersed phases used for the droplet templates generation were the photo-precursor solution that containing non-close-packed colloidal nanoparticles array in the poly(ethylene glycol) diacrylate (PEG-DA) medium, the non-spherical particles with ordered colloidal crystal structures were achieved after polymerizing the droplet templates in the confined collection capillaries. These non-close-packing colloidal crystal particles could be transformed into non-spherical close-packing colloidal crystal particles by a simply thermal processing. It was demonstrated that the non-spherical colloidal crystal particles with different sizes and structure colors, and with the shapes of rods, cuboids and disks could also be achieved. The resultant particles were with simple identification from their size, color or shape, thus they were ideal biocarriers for multiplex bioassay applications.(3) A one-step, continuous process for the scalable formation of microfibers with the desired features was developed by using novel capillary microfluidics. The method employed immediate microfiber gelation from multi-flows of sodium alginate (Na-alginate) solution and calcium chloride (CaCl2) solution at the orifice of an injection capillary, which was coaxially aligned with a collection capillary inside a square capillary. The resultant microfibers had the same structure as the injection flows. Other than just homogeneous structures, microfibers possessing anisotropic multicompartmental body, core, and shell compositions could also be generated by varying the injection capillary design. Furthermore, we also explored the potential use of these heterotypic microfibers for tissue-engineering applications by creating multifunctional fibers with a spatially controlled encapsulation of cells. The proposed microfibers may enable the construction of fiber-shaped tissues in natural organisms.