Interfacing nanodiamonds for single molecular optical-biomedical imaging
28 Aug 2011-pp 370-371
TL;DR: A versatile bioconjugation protocol to dock biomolecules on the colloidal diamond and demonstration of cellular internalization is presented.
Abstract: Luminescent nanodiamond is attractive for targeted drug-delivery and biolabelling due to its unique optical and chemical properties. A versatile bioconjugation protocol to dock biomolecules on the colloidal diamond and demonstration of cellular internalization is presented.
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TL;DR: This work shows how magneto-optical spin detection can be used to determine the location of a spin associated with a single nitrogen-vacancy centre in diamond with nanometre resolution under ambient conditions, and demonstrates the use of a single diamond spin as a scanning probe magnetometer to map nanoscale magnetic field variations.
Abstract: Magnetic resonance imaging and optical microscopy are key technologies in the life sciences. For microbiological studies, especially of the inner workings of single cells, optical microscopy is normally used because it easily achieves resolution close to the optical wavelength. But in conventional microscopy, diffraction limits the resolution to about half the wavelength. Recently, it was shown that this limit can be partly overcome by nonlinear imaging techniques, but there is still a barrier to reaching the molecular scale. In contrast, in magnetic resonance imaging the spatial resolution is not determined by diffraction; rather, it is limited by magnetic field sensitivity, and so can in principle go well below the optical wavelength. The sensitivity of magnetic resonance imaging has recently been improved enough to image single cells, and magnetic resonance force microscopy has succeeded in detecting single electrons and small nuclear spin ensembles. However, this technique currently requires cryogenic temperatures, which limit most potential biological applications. Alternatively, single-electron spin states can be detected optically, even at room temperature in some systems. Here we show how magneto-optical spin detection can be used to determine the location of a spin associated with a single nitrogen-vacancy centre in diamond with nanometre resolution under ambient conditions. By placing these nitrogen-vacancy spins in functionalized diamond nanocrystals, biologically specific magnetofluorescent spin markers can be produced. Significantly, we show that this nanometre-scale resolution can be achieved without any probes located closer than typical cell dimensions. Furthermore, we demonstrate the use of a single diamond spin as a scanning probe magnetometer to map nanoscale magnetic field variations. The potential impact of single-spin imaging at room temperature is far-reaching. It could lead to the capability to probe biologically relevant spins in living cells.
1,814 citations
"Interfacing nanodiamonds for single..." refers background in this paper
...Strong, spinsensitive NV-luminescence under ambient conditions provides an exceptional basis for quantum optics and nanoscale magnetometry [1]....
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TL;DR: The first direct observation of nitrogen-vacancy centres in discrete 5-nm nanodiamonds at room temperature is reported, including evidence for intermittency in the luminescence (blinking) from the nanod diamonds, and it is shown that it is possible to control this blinking by modifying the surface of the nanODiamonds.
Abstract: Nitrogen-vacancy colour centres in diamond can undergo strong, spin-sensitive optical transitions under ambient conditions, which makes them attractive for applications in quantum optics, nanoscale magnetometry and biolabelling. Although nitrogen-vacancy centres have been observed in aggregated detonation nanodiamonds and milled nanodiamonds, they have not been observed in very small isolated nanodiamonds. Here, we report the first direct observation of nitrogen-vacancy centres in discrete 5-nm nanodiamonds at room temperature, including evidence for intermittency in the luminescence (blinking) from the nanodiamonds. We also show that it is possible to control this blinking by modifying the surface of the nanodiamonds.
454 citations
"Interfacing nanodiamonds for single..." refers background in this paper
...In addition, low cytotoxicity and excellent photo-stability of LND makes it an attractive tool for biolabeling and cell targeted delivery purposes, especially, considering its size ranging from 4 nm and larger [2]....
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TL;DR: It is found that PEG derivatization dramatically suppresses the non-specific uptake while PEG-free carboxyl and amine functional groups promote QD internalization, which displayed a remarkable consistency across different cell types.
Abstract: We report a systematic empirical study of nanoparticle internalization into cells via non-specific pathways. The nanoparticles were comprised of commercial quantum dots (QDs) that were highly visible under a fluorescence confocal microscope. Surface-modified QDs with basic biologically-significant moieties, e.g. carboxyl, amino, streptavidin were used, in combination with the surface derivatization with polyethylene glycol (PEG) in a range of immortalized cell lines. Internalization rates were derived from image analysis and a detailed discussion about the effect of nanoparticle size, charge and surface groups is presented. We find that PEG-derivatization dramatically suppresses the non-specific uptake while PEG-free carboxyl and amine functional groups promote QD internalization. These uptake variations displayed a remarkable consistency across different cell types. The reported results are important for experiments concerned with cellular uptake of surface-functionalized nanomaterials, both when non-specific internalization is undesirable and also when it is intended for material to be internalized as efficiently as possible.
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117 citations
"Interfacing nanodiamonds for single..." refers background in this paper
...This non-specific internalization does engage the cell machinery and the internalization depends on the nanoparticle size, surface charge, and surface functional groups [4]....
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TL;DR: In this paper, a systematic empirical study of nanoparticle internalization into cells via non-specific pathways was conducted, where surface-modified QDs with basic biologically significant moieties, e.g. carboxyl, amino, and streptavidin, were used, in combination with surface derivatization with polyethylene glycol (PEG) for a range of immortalized cell lines.
Abstract: We report a systematic empirical study of nanoparticle internalization into cells via non-specific pathways. The nanoparticles were comprised of commercial quantum dots (QDs) that were highly visible under a fluorescence confocal microscope. Surface-modified QDs with basic biologically significant moieties, e.g. carboxyl, amino, and streptavidin, were used, in combination with surface derivatization with polyethylene glycol (PEG) for a range of immortalized cell lines. Internalization rates were derived from image analysis and a detailed discussion about the effect of nanoparticle size, charge and surface groups is presented. We find that PEG derivatization dramatically suppresses the non-specific uptake while PEG-free carboxyl and amine functional groups promote QD internalization. These uptake variations displayed a remarkable consistency across different cell types. The reported results are important for experiments concerned with cellular uptake of surface-functionalized nanomaterials, both when non-specific internalization is undesirable and when it is intended for material to be internalized as efficiently as possible.
116 citations
TL;DR: In this paper, the first demonstration of nanodiamond (ND) as a scattering optical label in a biological environment was reported, where NDs were efficiently transfected into cells using cationic liposomes, and imaged using differential interference and Hoffman modulation "space" contrast microscopy techniques.
50 citations
"Interfacing nanodiamonds for single..." refers background in this paper
...Several nanodiamond based biological imaging systems have been demonstrated before, for example, a micelle vehicle was capable of deliver 50-nm NDs in cells, non-specifically [3]....
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