scispace - formally typeset
Search or ask a question

Showing papers by "Andras Kis published in 2007"


Journal ArticleDOI
TL;DR: A nanoscale cell injection system (termed the nanoinjector) that uses carbon nanotubes to deliver cargo into cells and can deliver a discrete number of molecules to the cell's interior without the requirement of a carrier solvent is reported.
Abstract: Technologies for introducing molecules into living cells are vital for probing the physical properties and biochemical interactions that govern the cell's behavior. Here, we report the development of a nanoscale cell injection system (termed the nanoinjector) that uses carbon nanotubes to deliver cargo into cells. A single multiwalled carbon nanotube attached to an atomic force microscope (AFM) tip was functionalized with cargo via a disulfide-based linker. Penetration of cell membranes with this "nanoneedle" was controlled by the AFM. The following reductive cleavage of the disulfide bonds within the cell's interior resulted in the release of cargo inside the cells, after which the nanoneedle was retracted by AFM control. The capability of the nanoinjector was demonstrated by injection of protein-coated quantum dots into live human cells. Single-particle tracking was used to characterize the diffusion dynamics of injected quantum dots in the cytosol. This technique causes no discernible membrane or cell damage, and can deliver a discrete number of molecules to the cell's interior without the requirement of a carrier solvent.

378 citations


Journal ArticleDOI
TL;DR: In this paper, an atomic force microscope operated inside a transmission electron microscope was used to study the forces involved in buckling and kinking an individual multiwalled carbon nanotube while observing its structure.
Abstract: Using an atomic force microscope operated inside a transmission electron microscope, we have studied the forces involved in buckling and kinking an individual multiwalled carbon nanotube while observing its structure. In particular, we have measured an individual nanotube's asymptotic critical buckling load and critical kinking load. The buckling results are well described by classical elastic theory, while the observed kinking behavior requires a more involved analysis. Repeated buckling measurements on the same nanotube indicate an extremely high degree of elasticity and set a lower bound on the nanotube's yield strength of $1.7\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, higher than the yield strength of steel. Plastic deformation of the nanotube was eventually observed following kinking.

71 citations



Journal ArticleDOI
03 Sep 2007-Small
TL;DR: The objective was to establish an experimental procedure and show direct AFM measurements that unequivocally can be assigned as Young's modulus, and show consistent AFM values for mechanical coupling and nanowires.
Abstract: Keywords: atomic force microscopy ; mechanical coupling ; nanowires ; shear modulus ; Young's modulus Reference LNNME-ARTICLE-2008-041doi:10.1002/smll.200700164View record in Web of Science Record created on 2008-05-21, modified on 2016-08-08

25 citations