National Science Council (NSC) Project

A novel magnetic tweezers for manipulation and studying mechanical properties of single biomolecules

....The goal of the proposed two-year study is to design and fabricate a novel micro-magnetic tweezers utilizing MEMS technologies to manipulate DNA and actin filaments. The micromachined magnetic tweezers is capable of generating three-dimensional translational and rotational motions of a magnetic bead via a simple current control, which is enabling stretching and rotation of a single biomolecule. The key platform technologies including (1) micro-electromagnet fabrication, (2) localized single molecules immobilization, (3) micro-force measurement, (4) microfluidics, will been integrated to form the manipulation platform of a single molecule and a cell.

....We will use a highly efficient, highly specific, and strong binding method for the construction of DNA two sticky ends, which is compatible with MEMS techniques. A single DNA molecule is specifically attached onto a magnetic bead and a gold surface and will be manipulated under a magnetic field generated by built-in hexagonally-aligned micro-electromagnet. Likewise, a single actin filament could be manipulated using the similar affinity systems. Besides, a single molecule as a nano-wire could be extended between two nano-electrodes. We will develop a specific DNA immobilization platform to fix single DNA molecules and measure Ohm’s properties of the DNA.

....Design and optimization of the magnetic tweezers will be carried out by numerical simulation using the finite element analysis software. To quantify mechanical properties of an individual biomolecule and a living cell, force calibration will be performed by using the balance of gravity forces, hydrodynamic forces, and Brownian motion. Furthermore, verification of the single molecule biophysics will be carried out by the theoretical model.

....The novel magnetic tweezers will be applied to manipulate a single molecule and investigate physical properties of (1) a single DNA molecule, (2) a single actin filament, or (3) cell surfaces with a real-time fashion. This new tool has the following advantages over its large-scale counterparts including noninvasive, appropriate force range, excellent operation, fair measurability, cost-effectiveness, IC compatibility, and versatility to integrate with other MEMS devices. The proposed approach could provide a powerful tool for study of nano-biotechnology and improve our understanding of biophysical properties including flexibility, conductivity and thermodynamics.