Biological applications of multifunctional magnetic nanowires (invited)

Abstract

Magnetic particles that can be bound to cells and biomolecules have become an important tool for the application of force in biology and biotechnology. Multifunctional magnetic nanowires fabricated by electrochemical deposition in nanoporous templates are a type of magnetic carrier that offers significant potential advantages over commercially available magnetic particles. Recent experimental work aimed at developing these wires for this purpose is reviewed. Results on chemical functionalization of Au and Au/Ni wires and magnetic manipulation of wires in suspension are described. Fluorescence microscopy was used to demonstrate the covalent binding of thiol-terminated porphyrins to Au nanowires, and to optimize functionalization of two-segment gold–nickel nanowires for selectivity and stability of the nanowire–molecule linkages. Magnetic trapping is a technique where single nanowires are captured from fluid suspension using lithographically patterned micromagnets. The influence of an external magnetic field on this process is described. The dynamics of magnetic trapping is shown to be well described by a model based on the interplay of dipolar forces and viscous drag.

A nanomechanical device based on light-driven proton pumps

“…And the optical energy is estimated to be about 3.2 × 10 −8 J when the light with an intensity of 0.1 mW cm −2 calibrated by the laser powermeter (T148) illuminates the bR film on the microcantilever surface, whose dimensions are 200 µm in length, and 20 µm in width for each leg. Thus, the energy conversion efficiency according to equation (2) in our experiments is estimated to be about 0.000 0005%. This value is slightly lower than the energy conversion efficiency of 0.000 001% calculated by equation (2) when the light with an intensity about 6.5 mW cm −2 illuminates the microcantilever modified by a monolayer of azobenzene molecules in [53], whose dimensions are 180 µm in length, 40 µm in leg width, and 2 µm in thickness.…”

“…The integration of molecular biology and the physical sciences at micro-and nanoscales for constructing hybrid devices has undergone rapid development [1][2][3][4][5]. Important requirements for the construction of hybrid devices include (a) a suitable structure to act as a physical transducer for quantitative detection, (b) special biomaterials and molecules for converting chemical energy into mechanical energy, and (c) the implementation of interfacing technologies to combine the special biomaterials and molecules with the transducer.…”

Tailoring Staircase-like Hysteresis Loops in Electrodeposited Trisegmented Magnetic Nanowires: a Strategy toward Minimization of Interwire Interactions

“…The formation of NWs bundles is also a serious concern in applications that require the use of a single NW, for example when a single NW is intended to be bound to cells or proteins 32 …”

Biological application of multi-component nanowires in hybrid devices powered by F1-ATPase motors

“…If the applications of F 1 -ATPase motor were expanded in physical sciences, it requires the development of an easy method to fabricate and functionalize the propellers for the F 1 -motors. The electrochemical deposition technique provides a possibility with its broad range of applications in nanowires (Reich et al, 2003;Salem et al, 2004;Lapoinet et al, 2004).…”