Microfabricated micropallets for enhancement of biomolecular techniques

Abstract

We introduce microcarriers referred to as ''micropallets'' ranging in size from 25 lm to several 100 microns, fabricated using photoresist or other polymer materials. These small carrier structures may be used in static detection systems or for transporting attached biological or chemical samples through a microfluidic system. Micropallets may be encoded through the use of barcodes or other markings and engineered to optimally suit the cargo they carry. We demonstrate the use of micropallets in cell and antibody assays. Furthermore we demonstrate the ability to decode and manipulate micropallets in a flow-through system.

Encoded anisotropic particles for multiplexed bioanalysis

“…The aforementioned Kerr microscope incorporated a fluidic device to increase the efficiency of detection 97. Jensen‐McMullin et al have coupled a microfluidic readout system to an optical microscope for further analysis of their shape‐encoded photoresist micropallets 56. This fluidic device facilitated multiple experiments and collection of the particles at the end.…”

“…51 Similarly, particles fabricated from photoresist of varying shapes, that is, ovals, rectangles, squares, circles, were used in an immunoassay for polyclonal antibodies using fluorescence and brightfield microscopy. 56 A more advanced form of shape-encoded particles was developed using particles known as graticles 52 (Figure 3M). Rather than fluorescence-based detection of target binding, these particles take advantage of grating coupled SPR, in which a grating near the metallic surface is used to manipulate light for maximum surface plasmon excitation.…”

“…97 Jensen-McMullin et al have coupled a microfluidic readout system to an optical microscope for further analysis of their shape-encoded photoresist micropallets. 56 This fluidic device facilitated multiple experiments and collection of the particles at the end. To mimic micro total analysis systems with particles, Koh and coworkers have integrated encoded particle synthesis and functionalization with biological reactions and subsequent analysis in the same microfluidic device 51 (Figure 7A).…”

“…(Reproduced with permission from The Royal Society of Chemistry); (Q) optical images of 300 × 700 µm SU‐8 photoresist micropallets with nickel barcodes. (Adapted with kind permission from Ref 56. Copyright 2008 Springer Science + Business Media); (R) fluorescent false colored images of 20 × 100 µm encoded rare earth‐doped alkaline earth aluminosilicate glass microparticles.…”

“…Choi et al fabricated microfluidic devices for use in protein‐based fluorescence bioassays using hydrogel microparticles of varying size and shape (Figure 3L) to encapsulate the enzymes of interest within chambers of the microfluidic devices; substrates and fluorescent dye were introduced into the chamber for the detection process 51. Similarly, particles fabricated from photoresist of varying shapes, that is, ovals, rectangles, squares, circles, were used in an immunoassay for polyclonal antibodies using fluorescence and brightfield microscopy 56…”