Design and testing of a microfluidic biochip for cytokine enzyme-linked immunosorbent assay

Abstract

Enzyme-linked immunosorbent assay (ELISA) has been widely used in medical diagnostics, environmental analyses, and biochemical studies. To reduce assay time and lower consumption of reagents in cytokine ELISA analysis, a polymeric microfluidic biochip has been designed and fabricated via several new techniques: Polyaniline-based surface modification for superhydrophobic capillary valving and oxygen plasma-poly(ethyleneimine)-tyrosinase-protein A modification for high sensitivity protein detection. The proper flow sequencing was achieved using the superhydrophobic capillary valves. The burst frequency of each valve was experimentally determined and compared with two capillary force equations and the fluent finite element simulation. This fully automated microfluidic biochip with an analyzer is able to provide high fluorescence signal of ELISA with a wider linear detection range and a much shorter assay time than 96-well microtiter plates. It is applicable to a variety of nonclinic research and clinically relevant disease conditions. The modification technologies in this study can be implemented in other lab-on-a-chip systems, druggene delivery carriers, and other immunoassay biosensor applications.

An enzyme-linked immunosorbent assay on a centrifugal platform using magnetic beads

“…1,2,4,6,11 In addition, since the chemical reaction took place inside microchannel, the assay time was greatly reduced. 1,2,4,8,12,13 Therefore, a complete ELISA protocol can be performed on a disk platform through a programmed spinning control. Even though the disk-based ELISA has demonstrated its ability to be a better platform than the microtiter plate, there is still room for improvement.…”

“…In the last decade, it was proposed by many researchers to carry out ELISA on a disk platform (disk-based ELISA). [1][2][3][4][5][6][7][8][9][10] By utilizing the sequential flow control technique, reagents and wash buffers were delivered into the reaction chamber in sequence. 1,2,4,6,11 In addition, since the chemical reaction took place inside microchannel, the assay time was greatly reduced.…”

“…[1][2][3][4][5][6][7][8][9][10] By utilizing the sequential flow control technique, reagents and wash buffers were delivered into the reaction chamber in sequence. 1,2,4,6,11 In addition, since the chemical reaction took place inside microchannel, the assay time was greatly reduced. 1,2,4,8,12,13 Therefore, a complete ELISA protocol can be performed on a disk platform through a programmed spinning control.…”

“…The mass transport between the antigens in the liquid and the antibodies on the solid surface is limited and so does the assay sensitivity. 1,2,4 Magnetic beads emerged as an effective tool for bioassays. 12,[14][15][16] For a fixed amount of sample volume, magnetic beads can greatly increase the surface-to-volume ratio of the reaction sites.…”

“…1 Conventionally, ELISA is carried out using microtiter plates. Its procedure includes several liquid adding and removing steps for reagents and wash buffers.…”