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Abstract
The ability to visualize directly a large number of distinct molecular species inside cells is increasingly essential for understanding complex systems and processes. Even though existing methods have successfully been used to explore structure-function relationships in nervous systems, to profile RNA in situ, to reveal the heterogeneity of tumour microenvironments and to study dynamic macromolecular assembly, it remains challenging to image many species with high selectivity and sensitivity under biological conditions. For instance, fluorescence microscopy faces a 'colour barrier', owing to the intrinsically broad (about 1,500 inverse centimetres) and featureless nature of fluorescence spectra that limits the number of resolvable colours to two to five (or seven to nine if using complicated instrumentation and analysis). Spontaneous Raman microscopy probes vibrational transitions with much narrower resonances (peak width of about 10 inverse centimetres) and so does not suffer from this problem, but weak signals make many bio-imaging applications impossible. Although surface-enhanced Raman scattering offers high sensitivity and multiplicity, it cannot be readily used to image specific molecular targets quantitatively inside live cells. Here we use stimulated Raman scattering under electronic pre-resonance conditions to image target molecules inside living cells with very high vibrational selectivity and sensitivity (down to 250 nanomolar with a time constant of 1 millisecond). We create a palette of triple-bond-conjugated near-infrared dyes that each displays a single peak in the cell-silent Raman spectral window; when combined with available fluorescent probes, this palette provides 24 resolvable colours, with the potential for further expansion. Proof-of-principle experiments on neuronal co-cultures and brain tissues reveal cell-type-dependent heterogeneities in DNA and protein metabolism under physiological and pathological conditions, underscoring the potential of this 24-colour (super-multiplex) optical imaging approach for elucidating intricate interactions in complex biological systems.
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Zhou J, Gao PF, Zhang HZ, Lei G, Zheng LL, Liu H, Huang CZ. Color resolution improvement of the dark-field microscopy imaging of single light scattering plasmonic nanoprobes for microRNA visual detection. NANOSCALE 2017; 9:4593-4600. [PMID: 28322387 DOI: 10.1039/c6nr09452j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Imaging of light scattering plasmonic nanoparticles (PNPs) with the aid of the dark-field microscopy imaging (iDFM) technique has attracted wide attention owing to its high signal-to-noise ratio, but to improve the color resolution and contrast of dark-field microscopy (DFM) images of single light scattering PNPs in a small spectral variation environment is still a challenge. In this study, a new color analytical method for resolving the resolution and contrast in DFM images has been developed and further applied for colorimetric analysis using the digital image processing technique. The color of single light scattering PNP images is automatically coded at first with the hue values of the HSI color model, and then amplified using the MATLAB program even for marginal spectral changes, leading to significant improvement of the color resolution of DFM images and easy detection with the naked eye. As a proof of concept, this method is then applied to distinguish single PNPs with various sizes and to visually detect hepatocellular carcinoma-associated microRNA. As it greatly improved the color resolution of iDFM and its detection sensitivity, this method shows promise to serve as a better alternative for sensitive visual analysis and spectrometer-based spectral analysis.
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Affiliation(s)
- Jun Zhou
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China. and College of Computer and Information Science, Southwest University, Chongqing 400715, China
| | - Peng Fei Gao
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China.
| | - Hong Zhi Zhang
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China.
| | - Gang Lei
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China.
| | - Lin Ling Zheng
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China.
| | - Hui Liu
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China.
| | - Cheng Zhi Huang
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China. and Chongqing Key Laboratory of Biomedical Analysis (Southwest University), Chongqing Science & Technology Commission, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
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He R, Liu Z, Xu Y, Huang W, Ma H, Ji M. Stimulated Raman scattering microscopy and spectroscopy with a rapid scanning optical delay line. OPTICS LETTERS 2017; 42:659-662. [PMID: 28198892 DOI: 10.1364/ol.42.000659] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Stimulated Raman scattering (SRS) microscopy that is capable of both high-speed imaging and rapid spectroscopy will be advantageous for detailed chemical analysis of heterogeneous biological specimens. We have developed a system based on spectral focusing SRS technology with the integration of a rapid scanning optical delay line, which allows continuous tuning of SRS spectra by scanning a galvo mirror. We demonstrate SRS spectral measurements of dimethyl sulfoxide solution at low concentrations and multi-color imaging of rice pollens and HeLa cells with line-by-line delay tuning to reduce motion artifacts, as well as fast acquisition of SRS spectra at specific regions of interest.
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Yang W, Li A, Suo Y, Lu FK, Xie XS. Simultaneous two-color stimulated Raman scattering microscopy by adding a fiber amplifier to a 2 ps OPO-based SRS microscope. OPTICS LETTERS 2017; 42:523-526. [PMID: 28146518 PMCID: PMC6743724 DOI: 10.1364/ol.42.000523] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Stimulated Raman scattering (SRS) microscopy is a label-free chemical imaging technique. Two-color imaging is often necessary to determine the distribution of chemical species in SRS microscopy. Current multi-color SRS imaging methods involve complicated instrumentation or longer data acquisition time or are limited to transmission imaging. In this Letter, we show that by adding a simple fiber amplifier to a 2 ps laser source and optical-parametric-oscillator-based SRS setup, one can achieve simultaneous two-color or frequency modulation SRS microscopy. The fiber amplifier can generate a wavelength tunable laser of ±10 nm around the Stokes laser wavelength at 1031 nm with average power greater than 200 mW. In vivo and ex vivo lipid-protein imaging of mouse brain and skin is demonstrated. To further demonstrate the potential of this technique in high-speed in vivo imaging, white blood cells in a blood stream are imaged in a live mouse.
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Affiliation(s)
- Wenlong Yang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Ang Li
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- Current address: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Yuanzhen Suo
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Fa-Ke Lu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Neurosurgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, 02115, USA
| | - X. Sunney Xie
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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55
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Fu D, Yang W, Xie XS. Label-free Imaging of Neurotransmitter Acetylcholine at Neuromuscular Junctions with Stimulated Raman Scattering. J Am Chem Soc 2016; 139:583-586. [PMID: 28027644 DOI: 10.1021/jacs.6b10727] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Acetylcholine is an important neurotransmitter that relays neural excitation from lower motor neurons to muscles. It also plays significant roles in the central nervous system by modulating neurotransmission. However, there is a lack of tools to directly measure the quantity and distribution of acetylcholine at the subcellular level. In this Communication, we demonstrate for the first time that label-free imaging of acetylcholine is achieved with frequency-modulated spectral-focusing stimulated Raman scattering (FMSF-SRS) microscopy: a technical improvement over traditional SRS microscopy that effectively removes imaging backgrounds. Moreover, we directly quantified the local concentration of acetylcholine at the neuromuscular junction of frog cutaneous pectoris muscle.
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Affiliation(s)
- Dan Fu
- Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Wenlong Yang
- Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States
| | - Xiaoliang Sunney Xie
- Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States
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Jermyn M, Desroches J, Aubertin K, St-Arnaud K, Madore WJ, De Montigny E, Guiot MC, Trudel D, Wilson BC, Petrecca K, Leblond F. A review of Raman spectroscopy advances with an emphasis on clinical translation challenges in oncology. Phys Med Biol 2016; 61:R370-R400. [DOI: 10.1088/0031-9155/61/23/r370] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Ando J, Palonpon AF, Sodeoka M, Fujita K. High-speed Raman imaging of cellular processes. Curr Opin Chem Biol 2016; 33:16-24. [DOI: 10.1016/j.cbpa.2016.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/03/2016] [Indexed: 12/18/2022]
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58
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Liao CS, Cheng JX. In Situ and In Vivo Molecular Analysis by Coherent Raman Scattering Microscopy. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:69-93. [PMID: 27306307 PMCID: PMC5367927 DOI: 10.1146/annurev-anchem-071015-041627] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Coherent Raman scattering (CRS) microscopy is a high-speed vibrational imaging platform with the ability to visualize the chemical content of a living specimen by using molecular vibrational fingerprints. We review technical advances and biological applications of CRS microscopy. The basic theory of CRS and the state-of-the-art instrumentation of a CRS microscope are presented. We further summarize and compare the algorithms that are used to separate the Raman signal from the nonresonant background, to denoise a CRS image, and to decompose a hyperspectral CRS image into concentration maps of principal components. Important applications of single-frequency and hyperspectral CRS microscopy are highlighted. Potential directions of CRS microscopy are discussed.
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Affiliation(s)
- Chien-Sheng Liao
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907;
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907;
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Yue S, Cheng JX. Deciphering single cell metabolism by coherent Raman scattering microscopy. Curr Opin Chem Biol 2016; 33:46-57. [PMID: 27288951 DOI: 10.1016/j.cbpa.2016.05.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/18/2016] [Indexed: 11/20/2022]
Abstract
Metabolism is highly dynamic and intrinsically heterogeneous at the cellular level. Although fluorescence microscopy has been commonly used for single cell analysis, bulky fluorescent probes often perturb the biological activities of small biomolecules such as metabolites. Such challenge can be overcome by a vibrational imaging technique known as coherent Raman scattering microscopy, which is capable of chemically selective, highly sensitive, and high-speed imaging of biomolecules with submicron resolution. Such capability has enabled quantitative assessments of metabolic activities of biomolecules (e.g. lipids, proteins, nucleic acids) in single live cells in vitro and in vivo. These investigations provide new insights into the role of cell metabolism in maintenance of homeostasis and pathogenesis of diseases.
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Affiliation(s)
- Shuhua Yue
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, PR China.
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Department of Chemistry, Purdue University Center for Cancer Research, Birck Nanotechnology Center, Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA.
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Tokunaga K, Fang YC, Yokoyama H, Ozeki Y. Generation of synchronized picosecond pulses by a 1.06-µm gain-switched laser diode for stimulated Raman scattering microscopy. OPTICS EXPRESS 2016; 24:9617-28. [PMID: 27137575 DOI: 10.1364/oe.24.009617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We propose that a gain-switched laser diode (GS-LD) can be used as a picosecond laser source for stimulated Raman scattering (SRS) microscopy. We employed a 1.06-µm GS-LD to generate ~13-ps pulses at a repetition rate of 38 MHz and amplified them to >100 mW with Yb-doped fiber amplifiers. The GS-LD was driven by 200-ps electrical pulses, which were triggered through a toggle flip-flop (T-FF) so that the GS-LD pulses were synchronized to Ti:sapphire laser (TSL) pulses at a repetition rate of 76 MHz. We found the timing jitter of GS-LD pulses to be approximately 2.7 ps in a jitter bandwidth of 7 MHz. We also show that the delay of electrical pulses can be less sensitive to the optical power of TSL pulses by controlling the threshold voltage of the T-FF. We demonstrate the SRS imaging of polymer beads and of HeLa cells with GS-LD pulses and TSL pulses, proving that GS-LD is readily applicable to SRS microscopy as a compact and stable pulse source.
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