Simple and Fast Method To Fabricate Single-Nanoparticle-Terminated Atomic Force Microscope Tips

Abstract

This paper introduces a simple, yet controllable scheme to pick up a single 13 nm Au nanoparticle (Au-NP) using the tip of an atomic force microscope (AFM) probe through the application of electrical biases between the tip and the Au-NP. Transmission electron microscope (TEM) images were acquired to verify that a single Au-NP was attached to the AFM probe. We postulate that the mechanism underlying the ability to manipulate individual Au-NPs at the apex of the AFM probe tip is Coulomb interaction induced by tip bias. The AFM tip with the attached Au-NP was then used to study the interaction between a single quantum dot (QD) and the Au-NP. The blinking behavior of single colloidal CdSe/ZnS core/ shell QD was significantly suppressed with the approach of the 13 nm Au-NP attached to the AFM tip.

Single Molecule Take-and-Place Technique for Positioning a Membrane Protein on a Lipid Bilayer

“…For smTAP, a GNP as small as 1.8 nm in diameter was attached to the AFM tip by applying a suitable current limited bias voltage between the GNP and the AFM tip; the attachment was monitored by AFM. 16 Initially, GNPs were randomly spread on a doped silicon substrate and imaged by AFM in the tapping mode (Figure 2; left). The AFM tip was then placed directly in contact with a selected GNP by employing the force spectroscopy mode.…”

“…The reactive probe was incubated in 100 mM N,N-bis(carboxymethyl)-L-lysine hydrate and then in 40 mM NiSO 4 to form the nickel−nitrilotriacetic acid complex. 16 CtH + -PPase Protein Expression and Purification. The CtH + -PPase gene was inserted into pET23d vector (Novagen, Nottingham, UK) with a C terminal His 6 tag.…”

“…Individual GNP-modified AFM probes were subsequently immersed in 1 mM 16-mercaptohexadecanoid acid and then activated by 1-ethyl-3-(3-(dimethylamino)­propyl) carbodiimide before reaction with 5 mM sulfo- N -hydroxysuccinimide. The reactive probe was incubated in 100 mM N , N -bis­(carboxymethyl)- l -lysine hydrate and then in 40 mM NiSO 4 to form the nickel–nitrilotriacetic acid complex …”

Plasmonic nanospheres with a handle—Local electrochemical deposition of Au or Ag at the apex of optically inactive W- or C-tips

“…For example, direct nanostructuring at the tip apexes was achieved by focused ion beam milling, 8 lift-off of structured sacrificial layers, 9 local metal growth from metal filled carbon nanotubes by an electron beam, 10 selective metal deposition at the apex by partial passivation of the tip shaft, 11 or photocatalytic metal deposition. 12 Alternatively, single particles of plasmonic metals were attached to tips by picking them up with molecular glue, 4,13,14 capillary force, 15 coulomb interaction, 16 or alternating current dielectrophoresis. 17 However, most of these methods are time consuming and require several delicate preparation steps.…”

“…Typical sizes of the metal structures are of the order of 100 nm, although structures down to about 10-20 nm were reported. 11,13,16 In this letter, we use a one-step electrochemical method by which a small amount of gold or silver from a sacrificial substrate is transferred to the apex of an optically inactive tip, prepared, e.g., from tungsten or carbon. To localize the deposition process, short voltage pulses of typically 30 ns duration with amplitudes of up to 5.6 V were applied between the tip and a sacrificial Au or Ag surface in 1M LiCl/dimethyl sulfoxide (DMSO).…”