No abstract

Magnetophoresis is a motion of a magnetic or magnetizable particle induced by an inhomogeneous magnetic field in a fluid. Magnetophoretic immunoseparation, using micro- or nano-sized magnetic particles often modified by monoclonal or polyclonal antibodies for specific separation of biological or chemical targets, has shown a great potential in continuous-flow separation of cells and bacteria in clinical and biomedical fields. In this paper, the basic knowledge, key design considerations and recent developments on magnetophoretic immuno-separation of biological targets were reviewed.

A new method for online detection of peroxidase (POD) using 3D printing, active magnetic mixing, fluidic control, and optical detection was developed and demonstrated in this study. The proposed POD detection system consisted of a 3D printing and active magnetic mixing based fluidic chip for online catalytic reaction, an optical detector with a fluidic flow cell for quantitative determination of the final catalysate, and a single-chip microcontroller based controller for automatic control of two rotating magnetic fields and four precise peristaltic pumps. Horseradish peroxidase (HRP) was used as research model and a linear relationship between the absorbance at the characteristic wavelength of 450 nm and the concentration of HRP of 1/4–1/128 μg mL−1 was obtained as A  =  0.257ln⁡(C) + 1.425 (R2  = 0.976). For the HRP spiked pork tests, the recoveries of HRP ranged from 93.5% to 110.4%, indicating that this proposed system was capable of detecting HRP in real samples. It has the potential to be extended for online detection of the activity of other enzymes and integration with ELISA method for biological and chemical analysis.