title: Experimental investigation of magnetically actuated separation using tangential microfluidic channels and magnetic nanoparticles.
abstract: A novel continuous switching/separation scheme of magnetic nanoparticles (MNPs) in a sub-microlitre fluid volume surrounded by neodymium permanent magnet is studied in this work using tangential microfluidic channels. Polydimethylsiloxane tangential microchannels are fabricated using a novel micromoulding technique that can be done without a clean room and at much lower cost and time. Negligible switching of MNPs is seen in the absence of magnetic field, whereas 90% of switching is observed in the presence of magnetic field. The flow rate of MNPs solution had dramatic impact on separation performance. An optimum value of the flow rate is found that resulted in providing effective MNP separation at much faster rate. Separation performance is also investigated for a mixture containing non-magnetic polystyrene particles and MNPs. It is found that MNPs preferentially moved from lower microchannel to upper microchannel resulting in efficient separation. The proof-of-concept experiments performed in this work demonstrates that microfluidic bioseparation can be efficiently achieved using functionalised MNPs, together with tangential microchannels, appropriate magnetic field strength and optimum flow rates. This work verifies that a simple low-cost magnetic switching scheme can be potentially of great utility for the separation and detection of biomolecules in microfluidic lab-on-a-chip systems.
authors.affiliation: Department of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA.
authors.forename: Ahsan
authors.initials: A
authors.lastname: Munir
authors.affiliation: Department of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA.
authors.forename: Zanzan
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi 712100, People's Republic of China.
authors.forename: Jianlong
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA. szhou@wpi.edu.
authors.forename: Hong Susan
authors.initials: HS
authors.lastname: Zhou
mesh_terms: D002138:Calibration; D004867:Equipment Design; D060526:Magnetic Fields; D008280:Magnetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008422:Materials Testing; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D044085:Microfluidics / Q000379:methods; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D009354:Neodymium / Q000737:chemistry; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry
chemical_list: D058185:Magnetite Nanoparticles; D011137:Polystyrenes; D009354:Neodymium