Characterization of a Droplet Containing the Clustered Magnetic Beads Manipulation by Magnetically Actuated Chips

Abstract

A magnetically actuated chip was successfully developed in this study to perform the purpose of transportation for a droplet containing clustered magnetic beads. The magnetic field gradient is generated by the chip of the two-layer 4 × 4 array micro-coils, which was commercially fabricated by printing circuit board (PCB) technology. A numerical model was first established to investigate the magnetic field and thermal field for such a micro-coil. Consequently, the numerical simulations were in reasonable agreement with the experimental results. Moreover, a theoretical analysis was derived to predict the dynamic behaviors of the droplets. This analysis will offer the optimal operation for such a magnetically actuated chip. This study aims to successfully implement the concept of “digital microfluidics” in “point-of-care testing” (POCT). In the future, the micro-coil chip will be of substantial benefit to genetic analysis and infectious disease detection.

Magnetic Beads inside Droplets for Agitation and Splitting Manipulation by Utilizing a Magnetically Actuated Platform

“…A droplet-based mixer was agitated in four back-and-forth cycles to demonstrate uniform mixing quickly by using magnetic beads. The experimental results were consistent with previously reported findings [12]. The motion of microparticles within droplets can cause a significant mixing effect.…”

“…Substituting Equation (12) into Equation (11) and integrating yields the following formula: (Detailed in supplementary document S3).…”

“…where k and h are the thermal conductivity and heat convention coefficient, respectively. Substituting Equation (12) into Equation (11) and integrating yields the following formula: (Detailed in Supplementary Document S3).…”

“…In addition to their simplicity, portability, and ability to store samples and reagents on chips, droplet-actuated platforms are particularly useful for POCT. Droplet movement is effectively controlled by numerous actuated methods, including electrowetting on dielectric [ 2 ], thermocapillary force [ 3 ], surface acoustic waves [ 4 ], electrophoresis [ 5 ], optical force [ 6 ], and magnetic force [ 7 , 8 , 9 , 10 , 11 , 12 ]. Among all actuation devices, magnetic-actuated droplet manipulators [ 7 , 8 , 9 , 10 , 11 , 12 ] exhibit some advantages due to their flexibility, long distances, high driving forces, and easy use.…”

“…Droplet movement is effectively controlled by numerous actuated methods, including electrowetting on dielectric [ 2 ], thermocapillary force [ 3 ], surface acoustic waves [ 4 ], electrophoresis [ 5 ], optical force [ 6 ], and magnetic force [ 7 , 8 , 9 , 10 , 11 , 12 ]. Among all actuation devices, magnetic-actuated droplet manipulators [ 7 , 8 , 9 , 10 , 11 , 12 ] exhibit some advantages due to their flexibility, long distances, high driving forces, and easy use. Using droplets as micro-reactors, reagents can be transported, merged, mixed, and analyzed effectively [ 13 , 14 ].…”