Fluorescent Nanodiamond: A Versatile Tool for Long-Term Cell

Feb 16, 2016 - Biography. Wesley W.-W. Hsiao graduated from the Department of Chemical Engineering at the University of Waterloo in Canada. He obtaine...
6 downloads 11 Views 6MB Size
Download PDF
Article pubs.acs.org/accounts

Fluorescent Nanodiamond: A Versatile Tool for Long-Term Cell Tracking, Super-Resolution Imaging, and Nanoscale Temperature Sensing Wesley Wei-Wen Hsiao,† Yuen Yung Hui,† Pei-Chang Tsai,† and Huan-Cheng Chang*,†,§ †

Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan

§

CONSPECTUS: Fluorescent nanodiamond (FND) has recently played a central role in fueling new discoveries in interdisciplinary fields spanning biology, chemistry, physics, and materials sciences. The nanoparticle is unique in that it contains a high density ensemble of negatively charged nitrogen−vacancy (NV−) centers as built-in fluorophores. The center possesses a number of outstanding optical and magnetic properties. First, NV− has an absorption maximum at ∼550 nm, and when exposed to green-orange light, it emits bright fluorescence at ∼700 nm with a lifetime of longer than 10 ns. These spectroscopic properties are little affected by surface modification but are distinctly different from those of cell autofluorescence and thus enable background-free imaging of FNDs in tissue sections. Such characteristics together with its excellent biocompatibility render FND ideal for long-term cell tracking applications, particularly in stem cell research. Next, as an artificial atom in the solid state, the NV− center is perfectly photostable, without photobleaching and blinking. Therefore, the NV-containing FND is suitable as a contrast agent for super-resolution imaging by stimulated emission depletion (STED). An improvement of the spatial resolution by 20-fold is readily achievable by using a high-power STED laser to deplete the NV− fluorescence. Such improvement is crucial in revealing the detailed structures of biological complexes and assemblies, including cellular organelles and subcellular compartments. Further enhancement of the resolution for live cell imaging is possible by manipulating the charge states of the NV centers. As the “brightest” member of the nanocarbon family, FND holds great promise and potential for bioimaging with unprecedented resolution and precision. Lastly, the NV− center in diamond is an atom-like quantum system with a total electron spin of 1. The ground states of the spins show a crystal field splitting of 2.87 GHz, separating the ms = 0 and ±1 sublevels. Interestingly, the transitions between the spin sublevels can be optically detected and manipulated by microwave radiation, a technique known as optically detected magnetic resonance (ODMR). In addition, the electron spins have an exceptionally long coherence time, making FND useful for ultrasensitive detection of temperature at the nanoscale. Pump−probe-type nanothermometry with a temporal resolution of better than 10 μs has been achieved with a three-point sampling method. Gold/diamond nanohybrids have also been developed for highly localized hyperthermia applications. This Account provides a summary of the recent advances in FND-enabled technologies with a special focus on long-term cell tracking, super-resolution imaging, and nanoscale temperature sensing. These emerging and multifaceted technologies are in synchronicity with modern imaging modalities. spheres,2 metallic nanoclusters,3 and upconversion phosphors4 for bioimaging. Covalent conjugation of important biomolecules such as peptides, antibodies, nucleic acids, or smallmolecule ligands has enabled these nanoparticles to prospectively serve as cellular markers. However, the field of fluorescence bioimaging is not without problems, including degradation of the imaging probes, toxicity to biological samples, color fading, cell autofluorescence, strong light scattering from tissue, etc.

1. INTRODUCTION A leading force in modern life science research is fluorescence microscopy. It not only grants scientists the ability to visualize biological processes in cells and organisms but also permits tracking of molecules and cells in real time and three dimensions for disease identification and treatment. Today, we can correlate complex biochemical processes with the functioning of biomolecules in living cells at high precision thanks to a wealth of research on fluorescence microscopy. This is in part a result of the decade-long development of molecular tags in the form of fluorescent probes. Scientists in the 2000s have contributed much to the development of fluorescent nanoparticles including quantum dots,1 dye-doped nano© 2016 American Chemical Society

Received: October 30, 2015 Published: February 16, 2016 400

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407

Article

Accounts of Chemical Research The recent emergence of fluorescent nanodiamond (FND) has sparked a new era in cell labeling, imaging, and tracking with nanoparticles.5−7 This is attributed to the inherent biocompatibility and unique optical properties of this sp3carbon-based nanomaterial. However, unlike other fluorescent nanoparticles that can be synthesized with wet chemistry methods, FND can be fabricated only by physicochemical means under extreme conditions.7 Although the fabrication is technically demanding, it has benefited enormously from physicists who have carried out detailed characterization of the crystallographic defects in diamond both experimentally and theoretically since the 1950s.8,9 Researchers in the field are now working toward using surface-functionalized nanodiamonds for bioimaging, quantum sensing, and drug delivery.10 It has been reported that FNDs containing nitrogen-vacancy defect centers can emit bright, stable, and tissue-penetrating red photons. Additionally, the surface of FNDs can be conveniently derivatized with functional groups for protein and nucleic acid immobilization.11,12 FNDs let researchers visualize, track, and quantify molecules as well as cells with high spatial resolution, which is necessary should one wish to fully understand complex biological systems both in vitro and in vivo. As technological demands in life sciences increase, the surface-functionalized FNDs are expected to become one of the most favorable optical nanoprobes for biomedical imaging, diagnostics, and treatment. In the last 10 years, FNDs have attracted much attention from biologists, chemists, physicists, and material scientists because of their excellent mechanical, optical, chemical, and biomedical properties. Recently, many more innovative applications of FNDs are emerging. This Account touches on three new and significant areas, including long-term cell tracking, super-resolution imaging, and nanoscale temperature sensing, where FNDs are shown to be a versatile and powerful tool.

Figure 1. (a) Structure and (b) energy level diagram of the NV− center in diamond. The red sphere, blue dashed circle, and black spheres in (a) denote nitrogen, vacancy, and carbon atoms, respectively. The green, red, blue sinusoidal, and black dashed arrows in panel b denote optical excitation, fluorescence emission, microwave excitation, and intersystem crossing relaxation, respectively. (c) Comparison between the fluorescence spectrum of FNDs excited with a 532 nm laser and the near-infrared (NIR) window of biological tissue. (d) Comparison between the fluorescence lifetimes of FNDs in water and endogenous fluorophores in cells. Time gating at 10 ns is indicated for background-free detection.

molecule level by using optically detected magnetic resonance (ODMR) techniques at room temperature.15 Fourth, nearly 70% of the emitted photons lie in the near-infrared window (670−890 nm) of biological tissue (Figure 1c), and they can penetrate into tissue like skin for more than 2 mm.16 Fifth, the fluorescence lifetime of the emission is significantly longer than those of cell and tissue autofluorescence (∼20 ns versus ∼3 ns),17 which permits fluorescence imaging of single FNDs in cells and organisms by time gating (Figure 1d).18,19 Finally, background-free detection of the color centers can be accomplished by microwave and magnetic modulation of the NV− fluorescence.20−23 Conventionally, high-energy (typically 2 MeV) electrons from a van de Graaff accelerator are used as the damaging agents for vacancy creation.8 However, because the accelerator is difficult to access in both availability and cost, FNDs cannot be routinely produced. In response to this difficulty and the request for a larger quantity of the nanomaterials for biological applications, our group has explored the practicality of using a 40 keV He+ beam to construct high-density ensembles of NV− in type Ib diamonds.7,24 The advantage of this method is that the ion beam is high in flux but low in energy, allowing for fabrication of FNDs on a daily basis in a chemistry laboratory (Figure 2). To scale up the production, Boudou et al.25 have developed a high-yield fabrication method based on electron irradiation using a 10 MeV Rhodotron accelerator, followed by high-energy ball milling to reduce the particle size down to 10 nm. Cigler and co-workers alternatively employed a 15.5 MeV H+ beam to facilitate the process.26 Table 1 lists the experimental approaches that have been reported in literature.5,7,24−29 Having the capability of fabricating FNDs in large

2. THE NITROGEN−VACANCY CENTER Nitrogen is the most common impurity in diamond. It is responsible for the vast majority of impurity-related color formation.13 Man-made diamonds synthesized by highpressure−high-temperature methods usually contain 100 ppm of atomically dispersed nitrogen, classified as type Ib diamond. The submicrometer powders of these diamonds are convenient sources for FND fabrication. Vacancies in diamond are typically produced as a result of radiation damage under bombardment with high-energy particles such as electrons, neutrons, and ions.9 These lattice vacancies are structurally unstable and yet immobile at room temperature. They become mobile if the radiation-damaged sample is subjected to annealing at 600 °C or above to re-establish its crystalline structure. When one encounters a nitrogen atom in the next lattice position, it binds with that atom to form a stable NV complex (Figure 1a). The NV centers in diamond can exist in two different forms: NV0 and NV−. The latter deserves special attention because of its remarkable magneto-optical properties.14 First, the NV− center absorbs light strongly at 550 nm for the electronic transition 3A → 3E (Figure 1b), and its emission band peaks at 685 nm with a high fluorescence quantum yield. Second, the fluorescence emission is perfectly stable, undergoing neither photobleaching nor blinking, allowing for the detection of single NV− centers. Third, the electron spins in the ground state can be optically polarized, provided by the intersystem crossing in the excited state (Figure 1b), enabling optical readout of their spin states (ms = 0 and ±1) at the single 401

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407

Article

Accounts of Chemical Research

Figure 2. Schematic diagram (top view) and photograph (side view) of a 40-keV He+ ion beam facility for routine production of FNDs. A thin diamond film is prepared on a copper ribbon, which rolls in vacuum to allow continuous exposure of the nanoparticles to the ion beam for irradiation.

Table 1. Methods of Creating Vacancies in Nanodiamonds by Radiation Damage damaging agents

energy ranges

references

e− e− H+ H+ He+ H+, He+ H+, He+, Li+, N+

10 MeV 13.9 MeV 3 MeV 15.5 MeV 20 keV 40 keV 20−250 keV

25 27 5 26 28 7, 24 29

Figure 3. (a) Time-lapse images of a FND-labeled HeLa cell undergoing division, acquired by differential interference contrast and epifluorescence microscopy. The cell nuclei are stained in blue with Hoechst 33342, while the FNDs appear as red spots. Scale bars: 10 μm. (b) Long-term tracking of FND-labeled HeLa cells over 8 days by flow cytometry. The fluorescence intensity of each cell decreases exponentially with time due to cell proliferation. Reproduced with permission from ref 33. Copyright 2011 Wiley.

quantity, we have devoted our efforts to the development of NV− into bioimaging contrast agents and nanoscale quantum sensors since 2008.7 Three salient applications of the FNDs are illustrated in subsequent sections.

Stem cells are a group of undifferentiated biological cells that have the ability to self-renew and differentiate into various specialized cells. They are delicate and fragile, and their properties such as growth rate and differentiation capacity are prone to be affected by fluorescent labeling and gene transfection. To validate the aforementioned suggestion, we have applied the FND labeling technique to track the engraftment and regenerative capability of transplanted FNDlabeled lung stem cells (LSCs) in mouse models.34 In vitro experiments first verified that the FND labeling does not eliminate the cells’ properties of self-renewal and differentiation into type I and type II pneumocytes. The FND-labeled LSCs were then injected into lung-injured mice via intravenous administration. Mice were sacrificed at different time points and organs were collected to search for the injected LSCs by fluorescence microscopy. As commonly encountered in tissue section imaging, the high autofluorescence background level prevented clear identification of these cells in the lungs. Thanks to the distinct fluorescence lifetime of the NV− center, this undesirable effect could be largely removed by use of fluorescence time imaging microscopy (FLIM). Figure 4 shows FLIM images of the lung tissue collected on days 1 and 7.34 The injected cells can be clearly discerned, even when the cells are stained with hematoxylin and eosin (H&E) to aid

3. LONG-TERM CELL TRACKING An early work proposed that FNDs could be useful as singleparticle biomarkers.6 However, due to the large size of the nanomaterials (35−100 nm), FNDs are more suitable for use as cell trackers than molecular tags. A number of studies, including our own, have found that bare FNDs after acid wash can be spontaneously taken up by adherent cells in culture.30−33 Close examination of the uptake mechanism indicates that FNDs enter cells through energy-dependent, clathrin-mediated endocytosis and are subsequently trapped in endosomes and lysosomes.30−32 Notably, the internalization of FNDs does not cause any obvious cytotoxic and detrimental effects on the proliferation of human cells like HeLa cervical cancer cells. Figure 3a displays snap-shots of the real-time tracking of some internalized FNDs through the cell cycle of a FND-labeled HeLa cell by bright-field/epifluorescence microscopy.33 No significant exocytosis of FNDs is found even during the cell proliferation. This unique characteristic permits tracking of these cells continuously over a week (Figure 3b), suggesting that the FND can serve as a useful nanoprobe for long-term labeling and tracking of cell division, proliferation, and differentiation, particularly in stem cell research. 402

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407

Article

Accounts of Chemical Research

Figure 5. Comparison of the long-term tracking capability of EdU, CFSE, and FND. The assays are conducted for the mammospheres generated from AS-B145-1R cells labeled separately with EdU, CFSE, and FND and then dissociated for flow cytometric analysis with a 4day period for 20 days. Reproduced with permission from ref 35. Copyright 2015 Wiley.

Figure 4. Tracking the engraftment and regenerative capability of transplanted lung stem cells using FNDs in a lung-injured mouse model. Lung tissue sections are examined on days 1 and 7 after intravenous injection of the FND-labeled lung stem cells. Arrows indicate the identified cells. Scale bars: 50 μm. Reproduced with permission from ref 34. Copyright 2013 Nature Publishing Group.

4. SUPER-RESOLUTION IMAGING Fluorescence microscopy is a noninvasive, sensitive, and quantitative technique that has profoundly advanced our knowledge of cell biology. However, the revelation of the detailed structure of cellular organelles is limited by the diffraction of light. In the past decade, super-resolution fluorescence imaging has overcome this diffraction limit and substantially improved our ability to comprehend subcellular processes.36 Stimulated emission depletion (STED) microscopy is one of the techniques.37 In STED microscopy, two laser beams at different wavelengths are colinearly aligned with nanometric precision. The main laser beam brings the fluorophore of interest to its excited state, while the second laser beam, having a doughnut shape at its focus, depletes the fluorescence from all molecules except those in the middle of the excitation volume. Consequently, the resultant “fluorescent volume” becomes smaller than the diffraction limit. The higher the excitation power is, the smaller is the fluorescent volume and thus the higher is the image resolution. Being an exceptionally photostable fluorophore, the NV− centers are ideal to achieve the highest possible spatial resolution with STED. The STED microscopy was first employed by Hell and coworkers38,39 to detect single NV− centers in bulk diamond with a remarkable resolution of ∼6 nm. Using the same technique, our group has effectively procured high-resolution images of 35 nm FNDs spin-coated on a glass slide.40 We obtained a resolution of ∼40 nm, essentially limited by the size of the particles. A later study by Arroyo-Camejo et al.41 demonstrated that STED can resolve single NV− centers in 40−250 nm sized NDs with an improved resolution of ∼10 nm. There was no photobleaching even under intensive STED laser illumination (>100 MW/cm2). Leveraging this fact, we have applied STED to image FNDs taken up by HeLa cells. To prevent particle agglomeration in cell medium, we first coated FNDs noncovalently with bovine serum albumin (BSA) and delivered them into the cells by endocytosis (Figure 6a). Using green light for the excitation and a doughnut-shaped 740 nm laser beam for the depletion, an improvement of the spatial resolution from ∼240 to ∼40 nm has been reached for the BSA-coated FNDs in HeLa cells (Figure 6b,c). We isolated the

histological examination. The FND-labeled LSCs preferentially reside at the terminal bronchioles of the lungs on day 7 after intravenous administration, as confirmed by time-gated fluorescence (TGF) imaging of the tissue sections of naphthalene-injured mice with single-cell resolution. Additionally, the damaged lung cells can rapidly recover after transplantation of the FND-labeled LSCs into the mice. The method offers new insights into the components that limit the acceptance of the transplanted stem cells as well as the mechanism of their regeneration within a host. It holds great potential for monitoring the homing of different kinds of stem cells (such as mesenchymal stem cells) in larger animal models (such as miniature pigs) for preclinical experimentation. The extraordinary long-term tracking ability of FNDs led us to apply this methodology to find slow-proliferating and quiescent cancer stem cells (CSCs).35 These cells have long been considered to be a source of tumor initiation; however, there have been no effective tools for their identification and isolation even in vitro. FNDs are well suited for the purpose because they are both chemically and photophysically stable. Prior to the cell tracking experiments, we first carried out genotoxicity tests with comet and micronucleus assays for human fibroblasts and breast cancer cells to confirm that FNDs neither cause DNA damage nor impair cell growth. We then employed AS-B145-1R breast cancer cells as the model cell line for CSCs and compared in parallel the performance of FND with the commonly used cell trackers, carboxyfluorescein diacetate succinimidyl ester (CFSE) and 5-ethynyl-2′-deoxyuridine (EdU). Results indicate that our technique not only enables quantitative analysis of the FND-labeled cells by flow cytometry but also outperforms CFSE and EdU in regards to its long-term tracking capability (Figure 5). It is anticipated that further integration of the FND-based cell tracking platform with the functional assays of protein markers will greatly enhance our understanding of the CSCs both in vitro and in vivo. 403

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407

Article

Accounts of Chemical Research

can resolve the NV− centers in bulk diamond with a resolution of ∼4 nm at a STED laser power of ∼20 mW. Further decrease of the laser power by one more order of magnitude will make the technique better suitable for live cell imaging. It should be noted that other researchers in the field have also developed approaches to achieve subdiffraction imaging of single NV− centers on a parallel course. These include (1) deterministic emitter switch microscopy (DESM) with NV− manipulated by microwave radiation,43 (2) single-spin stochastic optical reconstruction microscopy (STORM) with the charge state of NV switching between −1 and 0,44 and (3) tip-enhanced fluorescence with FLIM in conjunction with atomic force microscopy.45,46 Taken together, the combination of the unique optical properties of FND with the subdiffraction imaging capability of STED microscopy and its variations has opened up exciting new opportunities to probe intracellular interactions and dynamics, not only with single-particle sensitivity but also with nanometric resolution and precision.

Figure 6. (a) Confocal fluorescence image of a HeLa cell labeled with BSA-coated FNDs by endocytosis. The corresponding image of the entire cell is given in the inset (white box). (b) STED image of single BSA-coated FNDs enclosed within the green box in panel a. (c) Comparison of confocal and STED fluorescence intensity profiles of the particle indicated in panel b with a blue line. Solid curves are best fits to one-dimensional Gaussian (confocal) or Lorentzian (STED) functions, with the corresponding full widths at half-maximum (fwhm) given in parentheses. Reproduced with permission from ref 40. Copyright 2011 Wiley.

5. NANOSCALE TEMPERATURE SENSING Thermogenesis is defined as a process in which the body of an organism generates heat. Visualizing thermal changes at subcellular resolution can reveal in depth the heat production processes and how they are correlated with biological activities. Recent advances in luminescence nanothermometry have made it practical to measure temperature changes in intracellular environment with high precision.47 The first application of FNDs as tiny thermometers in living cells was made in 2013 and has since aroused considerable interest in the scientific community.48 Although there are several notable achievements afterward,49−51 the field of the NV-based nanoscale temperature sensing is still in its infancy and possesses many obstructions to real-world applications. The NV− center in diamond has a triplet ground state with a total spin of 1. The ground state exhibits a crystal field splitting

individual FNDs in fixed cells and distinguished them from FND aggregates trapped in the endosomes. Despite the remarkable resolution that has been achieved with STED for single NV− centers, the high power of the STED beam is detrimental to super-resolution imaging of FNDs in living cells. To reduce the photodamage effect, converting NV− to NV0 by using a low power laser is a possible alternative. Chen et al.42 have recently explored this possibility and demonstrated that the charge-state depletion microscopy

Figure 7. (a) Covalent conjugation of polyarginine with carboxylated FNDs through carboxyl-to-amine cross-linking by carbodiimide chemistry for subsequent physical adsorption of bare GNRs. (b) TEM image of polyarginine-coated FNDs decorated with multiple 10 nm × 41 nm GNR particles. (c) Temperature rise of the FND in a GNR−FND hybrid heated by an 808 nm laser. Inset shows a typical fluorescence image of the spin-coated particle (denoted by the yellow arrow) used for the measurement. Reproduced with permission from ref 54. Copyright 2015 Springer. 404

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407

Article

Accounts of Chemical Research

Figure 8. (a) Experimental scheme for the time-resolved temperature measurement with a 100 nm FND particle submerged in aqueous solution containing 10 nm × 41 nm GNRs (black rods) heated by an 808 nm laser (red hyperboloid). (b) Time sequences of the laser, microwave, and detection pulses (all in μs) used in the time-resolved nanothermometry with a three-point method. The typical number of cycles is n = 70 000. (c) ODMR spectra of the GNR solution heated by the near-infrared laser with its power varying from 0 to 10 mW. (d) Time evolution of the heat dissipation of the GNR solution at the radial positions of r = 1.0 and 1.5 μm, as indicated in panel a.

of D = 2.87 GHz, which separates the ms = 0 and ±1 sublevels and can be measured by ODMR.49−51 Since a change in environmental temperature (T) can induce crystal strain, which in turn shifts the magnetic resonance, a precise measurement of the thermal shift (ΔD/ΔT), which varies from −75 kHz/K at 300 K to −150 kHz/K at 600 K,52,53 can expose the temperature change. Kucsko et al.48 have measured the electron spin resonance spectra of 100 nm FNDs in human embryonic fibroblasts with a continuous-wave laser and deduced the local temperature change with a precision of 0.1 K and a spatial resolution of 200 nm. They also introduced gold nanoparticles into the same cells as the heat source and demonstrated highprecision temperature control as well as thermal mapping at the subcellular level. To expand the versatility of this nanothermometry, we conjugated FNDs with gold nanorods (GNRs) using polyarginine as the interface to form dualfunctional nanoparticles (Figure 7a).54 More than one GNR (10 nm in diameter and 41 nm in length) can be attached to a single 100 nm FND (Figure 7b), making the nanohybrid an effective energy absorber and hence an efficient laser-activated nanoheater. The availability of these dual-functional nanoparticles has enabled us to achieve highly localized heating with a near-infrared laser (808 nm) and simultaneously probe the corresponding temperature changes in situ with ODMR for the individual gold/diamond nanohybrids (Figure 7c). The utility of these hybrid nanomaterials for hyper-localized hyperthermia applications is demonstrated with the endocytosed particles in HeLa cells. While measuring temperature at the nanoscale is important in many areas of science, much of the information about the underlying phenomena is contained in the dynamics. The FND provides a powerful new tool to disclose such information.

Enlightened by the fact that the widths of the ODMR peaks of NV− in FND are insensitive to temperature change,52,53 we have developed a three-point sampling method in conjunction with pump−probe-type spectroscopy to map the temporal profile of this physical parameter.51 In a proof-of-principle experiment, we conducted time-resolved temperature measurement for a GNR solution heated by a tightly focused 808 nm laser along with a 100 nm FND particle as the temperature sensor (Figure 8a). We then determined the ODMR peak shifts by measuring the fluorescence intensities of the FND being probed at three preselected microwave frequencies (f1, f 2, and f 3 as indicated in Figure 8b), instead of scanning the whole spectra. Results show that the method not only allows real-time monitoring of the temperature change over ±100 K (Figure 8c) but also permits detailed studies of the nanoscale heat transfer at a temporal resolution of better than 10 μs (Figure 8d).51

6. CONCLUSION The application of nanodiamonds in biomedicine is a conceptual breakthrough. While diamond has been prevailing as gems and industrial grinding materials for centuries, considerably less attention has been paid to its potential use in life sciences. It was first demonstrated in 2005 that FNDs containing high density ensembles of NV centers are brightly fluorescent and highly biocompatible,5 especially promising for biomedical applications. Since then, this sp3-bonded nanocarbon material has developed into a key element that is capable of bridging the information gap between physics and biology, placing the emerging new technologies including subdiffraction optical imaging and nanoscale quantum sensing within a subcellular context. 405

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407

Article

Accounts of Chemical Research

A. L. Yu, M.-S. Chang, and Y. T. Lee. We also thank Y.-K. Tzeng, V. Vaijayanthimala, C.-Y. Fang, B.-M. Chang, Y. Kuo, and H.-H. Lin for their important contributions. This work was supported by Academia Sinica and the Ministry of Science and Technology of Taiwan.

However, FNDs are not without their limitations. For instance, in order to meet some demanding bioimaging applications and to integrate it with the existing advanced protein labeling technologies such as HaloTag,55 there is a need to reduce the particle size down to at least 10 nm. Also, in vivo tracking of cells with good image contrast is an area still not well-developed, as researchers are struggling to adequately perform deep tissue imaging of FNDs at sufficient levels of sensitivity and resolution. Any of these improvements, if successful, will undoubtedly invite more talents to the field and lead to new advances in bioimaging and nanoscale sensing with unprecedented sensitivity, resolution, and precision.

■

■

REFERENCES

(1) Medintz, I. L.; Uyeda, H. T.; Goldman, E. R.; Mattoussi, H. Quantum Dot Bioconjugates for Imaging, Labelling and Sensing. Nat. Mater. 2005, 4, 435−446. (2) Yan, J. L.; Estevez, M. C.; Smith, J. E.; Wang, K. M.; He, X. X.; Wang, L.; Tan, W. H. Dye-Doped Nanoparticles for Bioanalysis. Nano Today 2007, 2, 44−50. (3) Zheng, J.; Nicovich, P. R.; Dickson, R. M. Highly Fluorescent Noble-Metal Quantum Dots. Annu. Rev. Phys. Chem. 2007, 58, 409− 431. (4) Bünzli, J.-C. G. Lanthanide Luminescence for Biomedical Analyses and Imaging. Chem. Rev. 2010, 110, 2729−2755. (5) Yu, S.-J.; Kang, M.-W.; Chang, H.-C.; Chen, K.-M.; Yu, Y.-C. Bright Fluorescent Nanodiamonds: No Photobleaching and Low Cytotoxicity. J. Am. Chem. Soc. 2005, 127, 17604−17605. (6) Fu, C.-C.; Lee, H.-Y.; Chen, K.; Lim, T.-S.; Wu, H.-Y.; Lin, P.-K.; Wei, P.-K.; Tsao, P.-H.; Chang, H.-C.; Fann, W. Characterization and Application of Single Fluorescent Nanodiamonds as Cellular Biomarkers. Proc. Natl. Acad. Sci. U. S. A. 2007, 104, 727−732. (7) Chang, Y.-R.; Lee, H.-Y.; Chen, K.; Chang, C.-C.; Tsai, D.-S.; Fu, C.-C.; Lim, T.-S.; Tzeng, Y.-K.; Fang, C.-Y.; Han, C.-C.; Chang, H.-C.; Fann, W. Mass Production and Dynamic Imaging of Fluorescent Nanodiamonds. Nat. Nanotechnol. 2008, 3, 284−288. (8) Davies, G.; Lawson, S. C.; Collins, A. T.; Mainwood, A.; Sharp, S. J. Vacancy-Related Centers in Diamond. Phys. Rev. B: Condens. Matter Mater. Phys. 1992, 46, 13157−13170. (9) Campbell, B.; Choudhury, W.; Mainwood, A.; Newton, M.; Davies, G. Lattice Damage Caused by the Irradiation of Diamond. Nucl. Instrum. Methods Phys. Res., Sect. A 2002, 476, 680−685. (10) Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y. The Properties and Applications of Nanodiamonds. Nat. Nanotechnol. 2011, 7, 11−23. (11) Chang, B.-M.; Lin, H.-H.; Su, L.-J.; Lin, W.-D.; Lin, R.-J.; Tzeng, Y.-K.; Lee, R. T.; Lee, Y. C.; Yu, A. L.; Chang, H.-C. Highly Fluorescent Nanodiamonds Protein-Functionalized for Cell Labeling and Targeting. Adv. Funct. Mater. 2013, 23, 5737−5745. (12) Alhaddad, A.; Adam, M.-P.; Botsoa, J.; Dantelle, G.; Perruchas, S.; Gacoin, T.; Mansuy, C.; Lavielle, S.; Malvy, C.; Treussart, F.; Bertrand, J.-R. Nanodiamond as a Vector for siRNA Delivery to Ewing Sarcoma Cells. Small 2011, 7, 3087−3095. (13) Zaitsev, A. M. Optical Properties of Diamond: A Data Handbook; Springer-Verlag GmbH: Berlin, 2001. (14) Schirhagl, R.; Chang, K.; Loretz, M.; Degen, C. L. NitrogenVacancy Centers in Diamond: Nanoscale Sensors for Physics and Biology. Annu. Rev. Phys. Chem. 2014, 65, 83−105. (15) Gruber, A.; Drabenstedt, A.; Tietz, C.; Fleury, L.; Wrachtrup, J.; von Borczyskowski, C. Scanning Confocal Optical Microscopy and Magnetic Resonance on Single Defect Centers. Science 1997, 276, 2012−2014. (16) Vaijayanthimala, V.; Cheng, P.-Y.; Yeh, S.-H.; Liu, K.-K.; Hsiao, C.-H.; Chao, J.-I.; Chang, H.-C. The Long-Term Stability and Biocompatibility of Fluorescent Nanodiamond as an In Vivo Contrast Agent. Biomaterials 2012, 33, 7794−7802. (17) Chang, C. W.; Sud, D.; Mycek, M. A. Fluorescence Lifetime Imaging Microscopy. Methods Cell Biol. 2007, 81, 495−524. (18) Faklaris, O.; Garrot, D.; Joshi, V.; Druon, F.; Boudou, J. P.; Sauvage, T.; Georges, P.; Curmi, P. A.; Treussart, F. Detection of Single Photoluminescent Diamond Nanoparticles in Cells and Study of the Internalization Pathway. Small 2008, 4, 2236−2239. (19) Kuo, Y.; Hsu, T.-Y.; Wu, Y.-C.; Chang, H.-C. Fluorescent Nanodiamond as a Probe for the Intercellular Transport of Proteins In Vivo. Biomaterials 2013, 34, 8352−8360.

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Notes

The authors declare no competing financial interest. Biographies Wesley W.-W. Hsiao graduated from the Department of Chemical Engineering at the University of Waterloo in Canada. He obtained his Ph.D. degree in Chemical Biology and Molecular Biophysics from the Taiwan International Graduate Program at Academia Sinica, the national academy of Taiwan. In 2013, he had been awarded top 100 Ph.D. On-the-Job Training Postdoctoral Fellowship, granted by the Taiwan government. He is presently working as a Postdoctoral Research Fellow on fluorescent nanodiamond research at the Institute of Atomic and Molecular Sciences of Academia Sinica. Yuen Yung Hui received his B.S. degree in Physics from the Chinese University of Hong Kong in 1996 and his Ph.D. degree in Physics from the same university in 2003. He worked at the Hong Kong Science and Technology Park on material characterization in the semiconductor industry from 2004 to 2005. Now he is working as a Postdoctoral Research Fellow at the Institute of Atomic and Molecular Sciences of Academia Sinica. His current research interest is focused on bioimaging and quantum sensing with fluorescent nanodiamonds. Pei-Chang Tsai graduated from the Department of Physics at Chung Yuan Christian University in 1996 and obtained his Ph.D. degree in Physics from National Taiwan Normal University in 2009. His expertise lies in lasers and optoelectronics. He has been working as a Postdoctoral Research Fellow at the Institute of Atomic and Molecular Sciences of Academia Sinica on optical and biomedical applications of fluorescent nanodiamonds since 2013. Huan-Cheng Chang received his B.S. degree in Agricultural Chemistry from National Taiwan University in 1981 and his Ph.D. degree in Physical Chemistry from Indiana University at Bloomington in 1990. He joined the Institute of Atomic and Molecular Sciences of Academia Sinica in 1994 and is now a Distinguished Research Fellow. His research interests are focused on the development of new methods, tools, and technologies based on physical chemistry and applying them to solve problems of biological and medicinal significance. He pioneered the development of single bioparticle mass spectrometry and nanodiamond-based optical bioimaging. His current research activities are devoted to the development and applications of surface-functionalized fluorescent nanodiamonds as diagnostic, imaging, sensing, and therapeutic tools.

■

ACKNOWLEDGMENTS The authors gratefully acknowledge the kind support and assistance from our collaborators, C.-C. Han, J.-H. Hsu, J. Yu, 406

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407

Article

Accounts of Chemical Research (20) Igarashi, R.; Yoshinari, Y.; Yokota, H.; Sugi, T.; Sugihara, F.; Ikeda, K.; Sumiya, H.; Tsuji, S.; Mori, I.; Tochio, H.; Harada, Y.; Shirakawa, M. Real-Time Background-Free Selective Imaging of Fluorescent Nanodiamonds In Vivo. Nano Lett. 2012, 12, 5726−5732. (21) Hegyi, A.; Yablonovitch, E. Molecular Imaging by Optically Detected Electron Spin Resonance of Nitrogen-Vacancies in Nanodiamonds. Nano Lett. 2013, 13, 1173−1178. (22) Chapman, R.; Plakhoitnik, T. Background-Free Imaging of Luminescent Nanodiamonds Using External Magnetic Field for Contrast Enhancement. Opt. Lett. 2013, 38, 1847−1849. (23) Sarkar, S. K.; Bumb, A.; Wu, X.; Sochacki, K. A.; Kellman, P.; Brechbiel, M. W.; Neuman, K. C. Wide-Field In Vivo Background Free Imaging by Selective Magnetic Modulation of Nanodiamond Fluorescence. Biomed. Opt. Express 2014, 5, 1190−1202. (24) Wee, T.-L.; Mau, Y.-W.; Fang, C.-Y.; Hsu, H.-L.; Han, C.-C.; Chang, H.-C. Preparation and Characterization of Green Fluorescent Nanodiamonds for Biological Applications. Diamond Relat. Mater. 2009, 18, 567−573. (25) Boudou, J. P.; Curmi, P. A.; Jelezko, F.; Wrachtrup, J.; Aubert, P.; Sennour, M.; Balasubramanian, G.; Reuter, R.; Thorel, A.; Gaffet, E. High Yield Fabrication of Fluorescent Nanodiamonds. Nanotechnology 2009, 20, 235602. (26) Havlik, J.; Petrakova, V.; Rehor, I.; Petrak, V.; Gulka, M.; Stursa, J.; Kucka, J.; Ralis, J.; Rendler, T.; Lee, S. Y.; Reuter, R.; Wrachtrup, J.; Ledvina, M.; Nesladek, M.; Cigler, P. Boosting Nanodiamond Fluorescence: Towards Development of Brighter Probes. Nanoscale 2013, 5, 3208−3211. (27) Dantelle, G.; Slablab, A.; Rondin, L.; Laine, F.; Carrel, F.; Bergonzo, P.; Perruchas, S.; Gacoin, T.; Treussart, F.; Roch, J. F. Efficient Production of NV Colour Centres in Nanodiamonds Using High-Energy Electron Irradiation. J. Lumin. 2010, 130, 1655−1658. (28) Mahfouz, R.; Floyd, D. L.; Peng, W.; Choy, J. T.; Loncar, M.; Bakr, O. M. Size-Controlled Fluorescent Nanodiamonds: A Facile Method of Fabrication and Color-Center Counting. Nanoscale 2013, 5, 11776−11782. (29) Sotoma, S.; Yoshinari, Y.; Igarashi, R.; Yamazaki, A.; Yoshimura, S. H.; Tochio, H.; Shirakawa, M.; Harada, Y. Effective Production of Fluorescent Nanodiamonds Containing Negatively-Charged NitrogenVacancy Centers by Ion Irradiation. Diamond Relat. Mater. 2014, 49, 33−38. (30) Vaijayanthimala, V.; Tzeng, Y.-K.; Chang, H.-C.; Li, C.-L. The Biocompatibility of Fluorescent Nanodiamonds and Their Mechanism of Cellular Uptake. Nanotechnology 2009, 20, 425103. (31) Faklaris, O.; Joshi, V.; Irinopoulou, T.; Tauc, P.; Sennour, M.; Girard, H.; Gesset, C.; Arnault, J. C.; Thorel, A.; Boudou, J.-P.; Curmi, P. A.; Treussart, F. Photoluminescent Diamond Nanoparticles for Cell Labeling: Study of the Uptake Mechanism in Mammalian Cells. ACS Nano 2009, 3, 3955−3962. (32) Perevedentseva, E.; Hong, S.-F.; Huang, K.-J.; Chiang, I.-T.; Lee, C.-Y.; Tseng, Y.-T.; Cheng, C.-L. Nanodiamond Internalization in Cells and the Cell Uptake Mechanism. J. Nanopart. Res. 2013, 15, 1384. (33) Fang, C.-Y.; Vaijayanthimala, V.; Cheng, C.-A.; Yeh, S.-H.; Chang, C.-F.; Li, C.-L.; Chang, H.-C. The Exocytosis of Fluorescent Nanodiamond and Its Use as a Long-Term Cell Tracker. Small 2011, 7, 3363−3370. (34) Wu, T.-J.; Tzeng, Y.-K.; Chang, W.-W.; Cheng, C.-A.; Kuo, Y.; Chien, C.-H.; Chang, H.-C.; Yu, J. Tracking the Engraftment and Regenerative Capabilities of Transplanted Lung Stem Cells Using Fluorescent Nanodiamonds. Nat. Nanotechnol. 2013, 8, 682−689. (35) Lin, H.-H.; Lee, H.-W.; Lin, R.-J.; Huang, C.-W.; Liao, Y.-C.; Fang, J.-M.; Chen, Y.-T.; Lee, T.-C.; Yu, A. L.; Chang, H.-C. Tracking and Finding Slow-Proliferating/Quiescent Cancer Stem Cells with Fluorescent Nanodiamonds. Small 2015, 11, 4394−4402. (36) Moerner, W. E. Single-Molecule Spectroscopy, Imaging, and Photocontrol: Foundations for Super-Resolution Microscopy (Nobel Lecture). Angew. Chem., Int. Ed. 2015, 54, 8067−8093. (37) Hell, S. W. Nanoscopy with Focused Light (Nobel Lecture). Angew. Chem., Int. Ed. 2015, 54, 8054−8066.

(38) Rittweger, E.; Han, K. Y.; Irvine, S. E.; Eggeling, C.; Hell, S. W. STED Microscopy Reveals Crystal Colour Centres with Nanometric Resolution. Nat. Photonics 2009, 3, 144−147. (39) Han, K. Y.; Willig, K. I.; Rittweger, E.; Jelezko, F.; Eggeling, C.; Hell, S. W. Three-Dimensional Stimulated Emission Depletion Microscopy of Nitrogen-Vacancy Centers in Diamond Using Continuous-Wave Light. Nano Lett. 2009, 9, 3323−3329. (40) Tzeng, Y.-K.; Faklaris, O.; Chang, B.-M.; Kuo, Y.; Hsu, J.-H.; Chang, H.-C. Superresolution Imaging of Albumin-Conjugated Fluorescent Nanodiamonds in Cells by Stimulated Emission Depletion. Angew. Chem., Int. Ed. 2011, 50, 2262−2265. (41) Arroyo-Camejo, S.; Adam, M. P.; Besbes, M.; Hugonin, J. P.; Jacques, V.; Greffet, J. J.; Roch, J. F.; Hell, S. W.; Treussart, F. Stimulated Emission Depletion Microscopy Resolves Individual Nitrogen Vacancy Centers in Diamond Nanocrystals. ACS Nano 2013, 7, 10912−10919. (42) Chen, X. D.; Zou, C. L.; Gong, Z. J.; Dong, C. H.; Guo, G. C.; Sun, F. W. Subdiffraction Optical Manipulation of the Charge State of Nitrogen Vacancy Center in Diamond. Light: Sci. Appl. 2015, 4, e230. (43) Chen, E. H.; Gaathon, O.; Trusheim, M. E.; Englund, D. WideField Multispectral Super-Resolution Imaging Using Spin-Dependent Fluorescence in Nanodiamonds. Nano Lett. 2013, 13, 2073−2077. (44) Pfender, M.; Aslam, N.; Waldherr, G.; Neumann, P.; Wrachtrup, J. Single-Spin Stochastic Optical Reconstruction Microscopy. Proc. Natl. Acad. Sci. U. S. A. 2014, 111, 14669−14674. (45) Hui, Y. Y.; Lu, Y.-C.; Su, L.-J.; Fang, C.-Y.; Hsu, J.-H.; Chang, H.-C. Tip-Enhanced Sub-Diffraction Fluorescence Imaging of Nitrogen-Vacancy Centers in Nanodiamonds. Appl. Phys. Lett. 2013, 102, 013102. (46) Beams, R.; Smith, D.; Johnson, T. W.; Oh, S.-H.; Novotny, L.; Vamivakas, A. N. Nanoscale Fluorescence Lifetime Imaging of an Optical Antenna with a Single Diamond NV Center. Nano Lett. 2013, 13, 3807−3811. (47) Jaque, D.; Vetrone, F. Luminescence Nanothermometry. Nanoscale 2012, 4, 4301−4326. (48) Kucsko, G.; Maurer, P. C.; Yao, N. Y.; Kubo, M.; Noh, H. J.; Lo, P. K.; Park, H.; Lukin, M. D. Nanometre-Scale Thermometry in a Living Cell. Nature 2013, 500, 54−58. (49) Neumann, P.; Jakobi, I.; Dolde, F.; Burk, C.; Reuter, R.; Waldherr, G.; Honert, J.; Wolf, T.; Brunner, A.; Shim, J. H.; Suter, D.; Sumiya, H.; Isoya, J.; Wrachtrup, J. High-Precision Nanoscale Temperature Sensing Using Single Defects in Diamond. Nano Lett. 2013, 13, 2738−2742. (50) Plakhotnik, T.; Doherty, M. W.; Cole, J. H.; Chapman, R.; Manson, N. B. All-Optical Thermometry and Thermal Properties of the Optically Detected Spin Resonances of the NV− Center in Nanodiamond. Nano Lett. 2014, 14, 4989−4996. (51) Tzeng, Y.-K.; Tsai, P.-C.; Liu, H.-Y.; Chen, O. Y.; Hsu, H.; Yee, F.-G.; Chang, M.-S.; Chang, H.-C. Time-Resolved Luminescence Nanothermometry with Nitrogen-Vacancy Centers in Nanodiamonds. Nano Lett. 2015, 15, 3945−3952. (52) Acosta, V. M.; Bauch, E.; Ledbetter, M. P.; Waxman, A.; Bouchard, L. S.; Budker, D. Temperature Dependence of the Nitrogen-Vacancy Magnetic Resonance in Diamond. Phys. Rev. Lett. 2010, 104, 070801. (53) Toyli, D. M.; Christle, D. J.; Alkauskas, A.; Buckley, B. B.; Van de Walle, C. G.; Awschalom, D. D. Measurement and Control of Single Nitrogen-Vacancy Center Spins above 600 K. Phys. Rev. X 2012, 2, 031001. (54) Tsai, P.-C.; Chen, O. Y.; Tzeng, Y.-K.; Hui, Y. Y.; Guo, J. Y.; Wu, C.-C.; Chang, M.-S.; Chang, H.-C. Gold/Diamond Nanohybrids for Quantum Sensing Applications. EPJ. Quantum Technol. 2015, 2, 19. (55) Los, G. V.; Wood, K. The HaloTag: A Novel Technology for Cell Imaging and Protein Analysis. Methods Mol. Biol. 2007, 356, 195− 208.

407

DOI: 10.1021/acs.accounts.5b00484 Acc. Chem. Res. 2016, 49, 400−407