Imaging nanoparticles in cells by nanomechanical holography

Abstract

Nanomaterials have potential medical applications, for example in the area of drug delivery, and their possible adverse effects and cytotoxicity are curently receiving attention. Inhalation of nanoparticles is of great concern, because nanoparticles can be easily aerosolized. Imaging techniques that can visualize local populations of nanoparticles at nanometre resolution within the structures of cells are therefore important. Here we show that cells obtained from mice exposed to single-walled carbon nanohorns can be probed using a scanning probe microscopy technique called scanning near field ultrasonic holography. The nanohorns were observed inside the cells, and this was further confirmed using micro Raman spectroscopy. Scanning near field ultrasonic holography is a useful technique for probing the interactions of engineered nanomaterials in biological systems, which will greatly benefit areas in drug delivery and nanotoxicology.

Beating beats mixing in heterodyne detection schemes

“…To illustrate the importance of beating in heterodyne measurements, we use the example of heterodyne force microscopy (HFM) [8][9][10] , as it represents a model system with a highly nonlinear mixing element (much higher order than quadratic). HFM enables the non-destructive imaging below a surface with nanometre resolution using an atomic force microscope [11][12][13][14][15][16][17][18][19] . The typical excitation scheme is sketched in Fig.…”

Nanometrology of Biomass for Bioenergy: The Role of Atomic Force Microscopy and Spectroscopy in Plant Cell Characterization

“…Simultaneous mechanical and chemical mapping have been obtained using mode synthesizing atomic force microscopy (MSAFM) (Tetard et al, 2008(Tetard et al, , 2010(Tetard et al, , 2011 and the additional spectroscopic capabilities of hybrid photonic nanomechanical force microscopy (HPFM) (Tetard et al, 2015;Farahi et al, 2017). Capitalizing on the nonlinear probe-sample forces, microscopy with MSAFM offers a way to image soft samples and probe nanostructures that are below their surfaces (subsurface imaging).…”

“…In both MSAFM and HPFM, the specific type of driving of the sample and the probe is selected based upon the specific application and the need for accessing subsurface, topographical, or chemical information. In general, both the probe and sample can be driven (Tetard et al, 2008) via any number and combination of waveform. In either case, the probe-sample interaction via the van der Waals force allows for synthesis of new oscillation modes in the system.…”

High-speed atomic force microscopy coming of age

“…In fact, when materials are embedded deeply from the sample surface (> 1 μm; much shorter than the wavelength of ultrasounds with a few MHz frequency), no sub-surface image appears on the acoustic phase image (unpublished data). It has been demonstrated that SNFUH has a capability of imaging artificial solid particles introduced in cells [190]. However, the live cell membranes are extremely soft, and therefore, it is likely that the cantilever tip deeply pushes the cell membrane to 29 sense the solid particles.…”