Automated Dielectrophoretic Tweezers-Based Force Spectroscopy System in a Microfluidic Device

Abstract

We reported an automated dielectrophoretic (DEP) tweezers-based force spectroscopy system to examine intermolecular weak binding interactions, which consists of three components: (1) interdigitated electrodes and micro-sized polystyrene particles used as DEP tweezers and probes inside a microfluidic device, along with an arbitrary function generator connected to a high voltage amplifier; (2) microscopy hooked up to a high-speed charge coupled device (CCD) camera with an image acquisition device; and (3) a computer aid control system based on the LabVIEW program. Using this automated system, we verified the measurement reliability by measuring intermolecular weak binding interactions, such as hydrogen bonds and Van der Waals interactions. In addition, we also observed the linearity of the force loading rates, which is applied to the probes by the DEP tweezers, by varying the number of voltage increment steps and thus affecting the linearity of the force loading rates. This system provides a simple and low-cost platform to investigate intermolecular weak binding interactions.

Variable Membrane Dielectric Polarization Characteristic in Individual Live Cells

“…In the forward and reverse frequency regions, the capture rates were 20 frames per second for all the FSRs, with a minimum resolution of 80 Hz/frame. The synchronization and resolution of each module in quantitatively measuring the DEP-induced motion of particles were verified in our previous work …”

“…The synchronization and resolution of each module in quantitatively measuring the DEP-induced motion of particles were verified in our previous work. 35 Method for Converting f co to Membrane Capacitance. By assuming that a cell membrane has very low membrane conductivity, the membrane capacitance is given by the following simple expression:…”

Non-Linear Cellular Dielectrophoretic Behavior Characterization Using Dielectrophoretic Tweezers-Based Force Spectroscopy inside a Microfluidic Device

“…The top of the reservoir was sealed by cover glass. An AC signal was applied to the contact pad on the chip using a custom probe station (Modusystems, Inc., Hanam, Korea) which connected to a LabVIEW (National Instruments, Austin, TX, USA)-based automated DEP system [ 35 ]. Numerous MCF-7 cells behaviors were observed and recorded under identical conditions using a charge-coupled device camera (Motionscope M3, Redlake, San Diego, CA, USA).…”

Optical Sensing Technologies to Elucidate the Interplay between Plant and Microbes

“…Plant surfaces can be profiled by various methods such as Raman spectroscopy, Positron emission tomography, X-ray fluorescence spectroscopy, or spectral imaging that do not require any optical probes [ 149 , 150 , 151 ]. Although there exist non-optical complementary techniques capable of measuring biomolecular interactions such as protein fragment complementation (PFC) [ 152 ], force spectroscopy (FS) [ 153 ], molecular recognition imaging (MRI) [ 154 ], and dielectrophoretic (DEP) tweezers [ 155 ], and optical biosensing probes provide a competitive advantage in terms of in situ, real-time, and low-cost sensing. This review article is centered around the optical biosensing probes, devices, and/or platforms that demonstrate the potential for in-situ plant monitoring at a much lower cost and simpler means.…”