1
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Schorr HC, Schultz ZD. Digital surface enhanced Raman spectroscopy for quantifiable single molecule detection in flow. Analyst 2024; 149:3711-3715. [PMID: 38895849 PMCID: PMC11229883 DOI: 10.1039/d4an00801d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 06/12/2024] [Indexed: 06/21/2024]
Abstract
Surface enhanced Raman scattering (SERS) provides a label free method of analyzing molecules from diverse and complex signals, potentially with single molecule sensitivity. The chemical specificity inherent in the SERS spectrum can identify molecules; however signal variability arising from the diversity of plasmonic environments can limit quantification, particularly at low concentrations. Here we show that digitizing, or counting SERS events, can decrease the limit of detection in flowing solutions enabling quantification of single molecules. By using multivariate curve resolution and establishing a score threshold, each individual spectrum can be classified as containing an event or not. This binary "yes/no" can then be quantified, and a linear region can be established. This method was shown to lower the limit of detection to the lowest physical limit, and lowered the limit of detection by an order of magnitude from the traditional, intensity based LOD calculations.
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Affiliation(s)
- Hannah C Schorr
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
| | - Zachary D Schultz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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2
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Morder CJ, Schultz ZD. A 3D printed sheath flow interface for surface enhanced Raman spectroscopy (SERS) detection in flow. Analyst 2024; 149:1849-1860. [PMID: 38347805 PMCID: PMC10926779 DOI: 10.1039/d3an02125d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/23/2024] [Indexed: 03/10/2024]
Abstract
Surface enhanced Raman spectroscopy (SERS) is an effective technique for detecting molecules in aqueous solutions due to its insensitivity to water, which makes it especially useful for biological samples. Utilizing SERS in flow can aid in a variety of applications such as metabolomics, pharmaceuticals, and diagnostics. The ability to 3D print complex objects enables rapid dissemination of prototypes. A 3D printed flow cell for sheath flow SERS detection has been developed that can incorporate a variety of planar substrates. The 3D printed flow cell incorporates hydrodynamic focusing, a sheath flow, that confines the analyte near the SERS substrate. Since the SERS signal obtained relies on the interaction between analyte molecules and nanostructures, sheath flow increases the detection efficiency and eliminates many issues associated with SERS detection in solution. This device was optimized by analyzing both molecules and particles with and without using sheath flow for SERS detection. Our results show that the flow rates can be optimized to increase the SERS signal obtained from a variety of analytes, and that the signal was increased when using sheath flow. This 3D printed flow cell offers a straightforward method to disseminate this technology and to facilitate online SERS detection.
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Affiliation(s)
- Courtney J Morder
- Department of Chemistry and Biochemistry, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210, USA.
| | - Zachary D Schultz
- Department of Chemistry and Biochemistry, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210, USA.
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3
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Itoh T, Procházka M, Dong ZC, Ji W, Yamamoto YS, Zhang Y, Ozaki Y. Toward a New Era of SERS and TERS at the Nanometer Scale: From Fundamentals to Innovative Applications. Chem Rev 2023; 123:1552-1634. [PMID: 36745738 PMCID: PMC9952515 DOI: 10.1021/acs.chemrev.2c00316] [Citation(s) in RCA: 86] [Impact Index Per Article: 86.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Indexed: 02/08/2023]
Abstract
Surface-enhanced Raman scattering (SERS) and tip-enhanced Raman scattering (TERS) have opened a variety of exciting research fields. However, although a vast number of applications have been proposed since the two techniques were first reported, none has been applied to real practical use. This calls for an update in the recent fundamental and application studies of SERS and TERS. Thus, the goals and scope of this review are to report new directions and perspectives of SERS and TERS, mainly from the viewpoint of combining their mechanism and application studies. Regarding the recent progress in SERS and TERS, this review discusses four main topics: (1) nanometer to subnanometer plasmonic hotspots for SERS; (2) Ångström resolved TERS; (3) chemical mechanisms, i.e., charge-transfer mechanism of SERS and semiconductor-enhanced Raman scattering; and (4) the creation of a strong bridge between the mechanism studies and applications.
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Affiliation(s)
- Tamitake Itoh
- Health
and Medical Research Institute, National
Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi-cho, Takamatsu, 761-0395Kagawa, Japan
| | - Marek Procházka
- Faculty
of Mathematics and Physics, Institute of Physics, Charles University, Ke Karlovu 5, 121 16Prague 2, Czech Republic
| | - Zhen-Chao Dong
- Hefei
National Research Center for Physical Sciences at the Microscale, University of Science and Technique of China, Hefei230026, China
| | - Wei Ji
- College
of Chemistry, Chemical Engineering, and Resource Utilization, Northeast Forestry University, Harbin145040, China
| | - Yuko S. Yamamoto
- School
of Materials Science, Japan Advanced Institute
of Science and Technology (JAIST), Nomi, 923-1292Ishikawa, Japan
| | - Yao Zhang
- Hefei
National Research Center for Physical Sciences at the Microscale, University of Science and Technique of China, Hefei230026, China
| | - Yukihiro Ozaki
- School of
Biological and Environmental Sciences, Kwansei
Gakuin University, 2-1,
Gakuen, Sanda, 669-1330Hyogo, Japan
- Toyota
Physical and Chemical Research Institute, Nagakute, 480-1192Aichi, Japan
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4
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Zoltowski CM, Shoup DN, Schultz ZD. Investigation of SERS Frequency Fluctuations Relevant to Sensing and Catalysis. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:14547-14557. [PMID: 37425396 PMCID: PMC10327581 DOI: 10.1021/acs.jpcc.2c03150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The excitation of plasmon resonances on nanoparticles generates locally enhanced electric fields commonly used for sensing applications and energetic charge carriers can drive chemical transformations as photocatalysts. The surface-enhanced Raman scattering (SERS) spectra from mercaptobenzoic acid (MBA) adsorbed to gold nanoparticles (AuNP) and silica encapsulated gold nanoparticles (AuNP@silica) can be used to assess the impact of energetic charge carriers on the observed signal. Measurements were recorded using a traditional point focused Raman spectroscopy and a wide-field spectral imaging approach to assess changes in the spectra of the different particles at increasing power density. The wide-field approach provides an increase in sampling statistics and shows evidence of SERS frequency fluctuations from MBA at low power densities, where it is commonly difficult to record spectra from a point focused spot. The increased spectral resolution of the point spectroscopy measurement provides improved peak identification and the ability to correlate the frequency fluctuations to charged intermediate species. Interestingly, our work suggests that isolated nanoparticles may undergo frequency fluctuations more readily than aggregates.
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Affiliation(s)
| | | | - Zachary D. Schultz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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5
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Shoup D, Scarpitti BT, Schultz ZD. A Wide-Field Imaging Approach for Simultaneous Super-Resolution Surface-Enhanced Raman Scattering Bioimaging and Spectroscopy. ACS MEASUREMENT SCIENCE AU 2022; 2:332-341. [PMID: 35996539 PMCID: PMC9389649 DOI: 10.1021/acsmeasuresciau.2c00013] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
High spatial resolution imaging and chemical-specific detection in living organisms is important in a wide range of fields from medicine to catalysis. In this work, we characterize a wide-field surface-enhanced Raman scattering (SERS) imaging approach capable of simultaneously capturing images and SERS spectra from nanoparticle SERS tags in cancer cells. By passing the image through a transmission diffraction grating before it reaches an array detector, we record the image and wavelength dispersed signal simultaneously on the camera sensor. Optimization of the experiment provides an approach with better spectral resolution and more rapid acquisition than liquid crystal tunable filters commonly used for wide-field SERS imaging. Intensity fluctuations inherent to SERS enabled localization algorithms to be applied to both the spatial and spectral domain, providing super-resolution SERS images that are correlated with improved peak positions identified in the spectrum of the SERS tag. The detected Raman signal is shown to be sensitive to the focal plane, providing three-dimensional (3D) sectioning abilities for the detected nanoparticles. Our work demonstrates spectrally resolved super-resolution SERS imaging that has the potential to be applied to complex physical and biological imaging applications.
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Affiliation(s)
- Deben
N. Shoup
- Department
of Chemistry and Biochemistry, The Ohio
State University, Columbus, Ohio 43210, United States
| | - Brian T. Scarpitti
- Department
of Chemistry and Biochemistry, The Ohio
State University, Columbus, Ohio 43210, United States
| | - Zachary D. Schultz
- Department
of Chemistry and Biochemistry, The Ohio
State University, Columbus, Ohio 43210, United States
- Comprehensive
Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
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6
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de Albuquerque CDL, Zoltowski CM, Scarpitti BT, Shoup DN, Schultz ZD. Spectrally Resolved Surface-Enhanced Raman Scattering Imaging Reveals Plasmon-Mediated Chemical Transformations. ACS NANOSCIENCE AU 2021; 1:38-46. [PMID: 34966910 PMCID: PMC8700175 DOI: 10.1021/acsnanoscienceau.1c00031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/26/2021] [Accepted: 10/28/2021] [Indexed: 02/08/2023]
Abstract
![]()
Challenges investigating
molecules on plasmonic nanostructures
have limited understanding of these interactions. However, the chemically
specific information in the surface-enhanced Raman scattering (SERS)
spectrum can identify perturbations in the adsorbed molecules to provide
insight relevant to applications in sensing, catalysis, and energy
conversion. Here, we demonstrate spectrally resolved SERS imaging,
to simultaneously image and collect the SERS spectra from molecules
adsorbed on individual nanoparticles. We observe intensity and frequency
fluctuations in the SERS signal on the time scale of tens of milliseconds
from n-mercaptobenzoic acid (MBA) adsorbed to gold
nanoparticles. The SERS signal fluctuations correlate with density
functional theory calculations of radicals generated by the interaction
between MBA and plasmon-generated hot electrons. Applying localization
microscopy to the data provides a super-resolution spectrally resolved
map that indicates the plasmonic-induced molecular charging occurs
on the extremities of the nanoparticles, where the localized electromagnetic
field is reported to be most intense.
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Affiliation(s)
| | - Chelsea M Zoltowski
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Brian T Scarpitti
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Deben N Shoup
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zachary D Schultz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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7
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Anik MI, Mahmud N, Al Masud A, Hasan M. Gold nanoparticles (GNPs) in biomedical and clinical applications: A review. NANO SELECT 2021. [DOI: 10.1002/nano.202100255] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Muzahidul I. Anik
- Department of Chemical Engineering University of Rhode Island South Kingstown Rhode Island USA
| | - Niaz Mahmud
- Department of Biomedical Engineering Military Institute of Science and Technology Dhaka Bangladesh
| | - Abdullah Al Masud
- Department of Chemical Engineering Bangladesh University of Engineering and Technology Dhaka Bangladesh
| | - Maruf Hasan
- Department of Biomedical Engineering Military Institute of Science and Technology Dhaka Bangladesh
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8
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Zong C, Chen CJ, Wang X, Hu P, Liu GK, Ren B. Single-Molecule Level Rare Events Revealed by Dynamic Surface-Enhanced Raman Spectroscopy. Anal Chem 2020; 92:15806-15810. [PMID: 33237721 DOI: 10.1021/acs.analchem.0c02936] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) is a powerful tool to monitor various interfacial behaviors providing molecular level information with high spatial and temporal resolutions. However, it is a challenge to obtain SERS spectra with high quality for analytes having a weak binding affinity with plasmonic nanostructures due to the short dwell time of the analyte on the surface. Here, we employed dynamic SERS, an acquisition method consisting of the rapid acquisition of a series of consecutive SERS spectra, to study the adsorption/desorption behavior of R6G on Ag surfaces. We demonstrated that the signal-noise ratio of SERS spectra of mobile molecules can be improved by dynamic SERS even when the acquisition time cannot catch up with the diffusion time of the molecule. More interestingly, we captured the neutral R6G0 state (spectroscopically different from the dominated positive R6G+ state) of R6G at the single-molecule level, which is a rare molecule event hardly detectable by traditional SERS. Dynamic SERS provides near real-time molecular vibrational information with an improved signal-noise ratio, which opens a new avenue to capture metastable or rare molecule events for the comprehensive understanding of interfacial processes related to catalysis and life science.
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Affiliation(s)
- Cheng Zong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chan-Juan Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiang Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Pei Hu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Guo-Kun Liu
- State Key Laboratory of Marine Environmental Science, Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Center for Marine Environmental Chemistry & Toxicology, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Bin Ren
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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9
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Wang C, Xiao L, Dai C, Nguyen AH, Littlepage LE, Schultz ZD, Li J. A Statistical Approach of Background Removal and Spectrum Identification for SERS Data. Sci Rep 2020; 10:1460. [PMID: 31996718 PMCID: PMC6989639 DOI: 10.1038/s41598-020-58061-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 01/10/2020] [Indexed: 11/24/2022] Open
Abstract
SERS (surface-enhanced Raman scattering) enhances the Raman signals, but the plasmonic effects are sensitive to the chemical environment and the coupling between nanoparticles, resulting in large and variable backgrounds, which make signal matching and analyte identification highly challenging. Removing background is essential, but existing methods either cannot fit the strong fluctuation of the SERS spectrum or do not consider the spectra’s shape change across time. Here we present a new statistical approach named SABARSI that overcomes these difficulties by combining information from multiple spectra. Further, after efficiently removing the background, we have developed the first automatic method, as a part of SABARSI, for detecting signals of molecules and matching signals corresponding to identical molecules. The superior efficiency and reproducibility of SABARSI are shown on two types of experimental datasets.
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Affiliation(s)
- Chuanqi Wang
- University of Notre Dame, Department of Applied and Computational Mathematics and Statistics, Notre Dame, IN, 46556, United States
| | - Lifu Xiao
- The Ohio State University, Department of Chemistry and Biochemistry, Columbus, OH, 43210, United States
| | - Chen Dai
- University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, IN, 46556, United States.,Harper Cancer Research Institute, South Bend, IN, 46617, United States
| | - Anh H Nguyen
- University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, IN, 46556, United States
| | - Laurie E Littlepage
- University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, IN, 46556, United States.,Harper Cancer Research Institute, South Bend, IN, 46617, United States
| | - Zachary D Schultz
- The Ohio State University, Department of Chemistry and Biochemistry, Columbus, OH, 43210, United States.,University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, IN, 46556, United States.,Harper Cancer Research Institute, South Bend, IN, 46617, United States
| | - Jun Li
- University of Notre Dame, Department of Applied and Computational Mathematics and Statistics, Notre Dame, IN, 46556, United States. .,Harper Cancer Research Institute, South Bend, IN, 46617, United States.
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10
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dos Santos DP, Temperini MLA, Brolo AG. Intensity Fluctuations in Single-Molecule Surface-Enhanced Raman Scattering. Acc Chem Res 2019; 52:456-464. [PMID: 30668089 DOI: 10.1021/acs.accounts.8b00563] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Around 20 years ago, the first reports of single-molecule surface-enhanced Raman scattering (SM-SERS) caused a revolution in nanotechnology. Several researchers were quick to recognize the importance of a technique that can provide molecular vibrational fingerprinting at the SM level. Since then, a large amount of work has been devoted to the development of nanostructures capable of SM-SERS detection. A great effort has also been geared toward elucidating the different mechanisms that contribute to the effect. The understanding of the concept of plasmonic SERS hotspots, the role of chemical effects, and the dynamics of atomic and cluster rearrangements in nanometric domains has significantly advanced, driven by new computational and experimental methods used to study SM-SERS. In particular, SERS intensity fluctuations (SIFs) are now recognized as a hallmark of SM-SERS. Interpretation of SM-SERS data must take into consideration temporal and spatial variations as a natural consequence of the extreme localization inherent to surface plasmon resonances. Further analysis of variations in spectral signature, due to either molecular reorientation or photo (or thermal) processes, pointed to a new area that combines the power of SERS fingerprinting at the SM level to modern concepts of catalysis, such as hot-electrons-driven chemistry. This large body of work on the fundamental characteristics of the SM-SERS effect paved the way to the interpretation of other related phenomena, such as tip-enhanced Raman scattering (TERS). Despite all the fundamental progress, there are still very few examples of real applications of SM-SERS. In recent years, our research group has been studying SIFs, focused on different ways to use SM-SERS. The obvious application of SM-SERS is in analytical chemistry, particularly for quantification at ultralow concentrations (below 1 nM). However, quantification using SM-SERS faces a fundamental sampling problem: the analytes (adsorbed in very small amounts, i.e., low surface coverage) must find rare SERS hotspots (areas with intense electric field localization that yields SERS). This limitation leads to strong temporal and spatial variations in SERS intensities, which translates into very large error bars in an experimental calibration curve. We tackled this problem by introducing the concept of "digital SERS". This approach provided a roadmap for SERS quantification at ultralow concentrations and a potential pathway for a better understanding of the "reproducibility problem" associated with SERS. In this Account, we discuss not only the analytical applications but also other implementations of SM-SERS demonstrated by our group. These include the use of SM-SERS as a tool to probe colloidal aggregation, to evaluate the efficiency of SERS substrates, and to characterize the energy of localized resonances. SERS involves a series of random processes: hotspots are rare; surfaces/clusters constantly reconstruct; and molecules diffuse, adsorb, and desorb. All these pathways contribute to strong fluctuations in SERS intensities. Our work indicates that a statistical view of the effect can lead to interesting insights and the potential to fulfill the promise of this SM technique for real-world applications.
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Affiliation(s)
- Diego P. dos Santos
- Departamento de Físico-Química, Instituto de Química, Universidade Estadual de Campinas, CP 6154, CEP 13083-970, Campinas, SP, Brazil
| | - Marcia L. A. Temperini
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26.077, CEP 05513-970, São Paulo, SP, Brazil
| | - Alexandre G. Brolo
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria V8W 3 V6, BC Canada
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11
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Zong C, Xu M, Xu LJ, Wei T, Ma X, Zheng XS, Hu R, Ren B. Surface-Enhanced Raman Spectroscopy for Bioanalysis: Reliability and Challenges. Chem Rev 2018; 118:4946-4980. [PMID: 29638112 DOI: 10.1021/acs.chemrev.7b00668] [Citation(s) in RCA: 876] [Impact Index Per Article: 146.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Surface-enhanced Raman spectroscopy (SERS) inherits the rich chemical fingerprint information on Raman spectroscopy and gains sensitivity by plasmon-enhanced excitation and scattering. In particular, most Raman peaks have a narrow width suitable for multiplex analysis, and the measurements can be conveniently made under ambient and aqueous conditions. These merits make SERS a very promising technique for studying complex biological systems, and SERS has attracted increasing interest in biorelated analysis. However, there are still great challenges that need to be addressed until it can be widely accepted by the biorelated communities, answer interesting biological questions, and solve fatal clinical problems. SERS applications in bioanalysis involve the complex interactions of plasmonic nanomaterials with biological systems and their environments. The reliability becomes the key issue of bioanalytical SERS in order to extract meaningful information from SERS data. This review provides a comprehensive overview of bioanalytical SERS with the main focus on the reliability issue. We first introduce the mechanism of SERS to guide the design of reliable SERS experiments with high detection sensitivity. We then introduce the current understanding of the interaction of nanomaterials with biological systems, mainly living cells, to guide the design of functionalized SERS nanoparticles for target detection. We further introduce the current status of label-free (direct) and labeled (indirect) SERS detections, for systems from biomolecules, to pathogens, to living cells, and we discuss the potential interferences from experimental design, measurement conditions, and data analysis. In the end, we give an outlook of the key challenges in bioanalytical SERS, including reproducibility, sensitivity, and spatial and time resolution.
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Affiliation(s)
- Cheng Zong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Mengxi Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Li-Jia Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Ting Wei
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Xin Ma
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Xiao-Shan Zheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Ren Hu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
| | - Bin Ren
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China
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12
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Süleymanoğlu E. Mg 2+-induced DNA compaction, condensation, and phase separation in gene delivery vehicles based on zwitterionic phospholipids: a dynamic light scattering and surface-enhanced Raman spectroscopic study. J Biol Inorg Chem 2017; 22:1165-1177. [PMID: 28924921 DOI: 10.1007/s00775-017-1492-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/28/2017] [Indexed: 01/08/2023]
Abstract
Despite the significant efforts towards applying improved non-destructive and label-free measurements of biomolecular structures of lipid-based gene delivery vectors, little is achieved in terms of their structural relevance in gene transfections. Better understanding of structure-activity relationships of lipid-DNA complexes and their gene expression efficiencies thus becomes an essential issue. Raman scattering offers a complimentary measurement technique for following the structural transitions of both DNA and lipid vesicles employed for their transfer. This work describes the use of SERS coupled with light scattering approaches for deciphering the bioelectrochemical phase formations between nucleic acids and lipid vesicles within lipoplexes and their surface parameters that could influence both the uptake of non-viral gene carriers and the endocytic routes of interacting cells. As promising non-viral alternatives of currently employed risky viral systems or highly cytotoxic cationic liposomes, complexations of both nucleic acids and zwitterionic lipids in the presence of Mg2+ were studied applying colloidal Ag nanoparticles. It is shown that the results could be employed in further conformational characterizations of similar polyelectrolyte gene delivery systems.
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Affiliation(s)
- Erhan Süleymanoğlu
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Gazi University, 06330, Ankara, Turkey.
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13
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Bailey KA, Schultz ZD. Tracking Bulk and Interfacial Diffusion Using Multiplex Coherent Anti-Stokes Raman Scattering Correlation Spectroscopy. J Phys Chem B 2016; 120:6819-28. [PMID: 27322504 PMCID: PMC4962611 DOI: 10.1021/acs.jpcb.6b04304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Multiplex coherent anti-Stokes Raman scattering correlation spectroscopy (CARS-CS) is shown as a label-free, chemically specific approach for monitoring the molecular mobility of particles in solution and at interfaces on the millisecond time scale. The CARS spectral range afforded by broadband excitation facilitates a quantitative measurement for the number of particles in the focal volume, whereas the autocorrelation of spectral data elucidates dynamic events, such as diffusion. The measured diffusion coefficients for polymer beads ranging from 100 nm to 1.1 μm in diameter are on the order of 10(-8)-10(-9) cm(2)/s, in good agreement with predicted Stokes-Einstein values. Diffusion at different interfaces shows particles are fastest in bulk medium, marginally slower at the liquid/glass interface, and 1.5-2 times slower rate at the air/liquid interface. Multivariate curve resolution analysis of distinct spectral features in multiplex CARS measurement distinguishes different composition lipid vesicles in a mixture diffusing through the focal volume. The observed diffusion is consistent with results obtained from single particle tracking experiments. This work demonstrates the utility of multiplex CARS correlation spectroscopy for monitoring particle diffusion from different chemical species across diverse interfaces.
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Affiliation(s)
- Karen A. Bailey
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Zachary D. Schultz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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14
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Riordan CM, Jacobs KT, Negri P, Schultz ZD. Sheath flow SERS for chemical profiling in urine. Faraday Discuss 2016; 187:473-84. [PMID: 27034996 PMCID: PMC4920711 DOI: 10.1039/c5fd00155b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The molecular specificity and sensitivity of surface enhanced Raman scattering (SERS) makes it an attractive method for biomedical diagnostics. Here we present results demonstrating the utility and complications for SERS characterization in urine. The chemical fingerprint characteristics of Raman spectra suggest its use as a label free diagnostic; however, the complex composition of biological fluids presents a tremendous challenge. In particular, the limited number of surface sites and competing absorption tend to mask the presence of analytes in solution, particularly when the solution contains multiple analytes. To address these problems and characterize biological fluids we have demonstrated a sheath-flow interface for SERS detection. This sheath-flow SERS interface uses hydrodynamic focusing to confine analyte molecules eluting out of a column onto a planar SERS substrate where the molecules are detected by their intrinsic SERS signal. In this report we compare the direct detection of benzoylecgonine in urine using DSERS with chemical profiling by capillary zone electrophoresis and sheath-flow SERS detection. The SERS spectrum from the observed migration peaks can identify benzoylecgonine and other distinct spectra are also observed, suggesting improved chemical diagnostics in urine. With over 2000 reported compounds in urine, identification of each of the detected species is an enormous task. Nonetheless, these samples provide a benchmark to establish the potential clinical utility of sheath-flow SERS detection.
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Affiliation(s)
- Colleen M Riordan
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Kevin T Jacobs
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Pierre Negri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Zachary D Schultz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
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15
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Kerman S, Chen C, Li Y, Van Roy W, Lagae L, Van Dorpe P. Raman fingerprinting of single dielectric nanoparticles in plasmonic nanopores. NANOSCALE 2015; 7:18612-8. [PMID: 26490057 DOI: 10.1039/c5nr05341b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Plasmonic nano-apertures are commonly used for the detection of small particles such as nanoparticles and proteins by exploiting electrical and optical techniques. Plasmonic nanopores are metallic nano-apertures sitting on a thin membrane with a tiny hole. It has been shown that plasmonic nanopores with a given geometry identify internal molecules using Surface Enhanced Raman Spectroscopy (SERS). However, label-free identification of a single dielectric nanoparticle requires a highly localized field comparable to the size of the particle. Additionally, the particle's Brownian motion can jeopardize the amount of photons collected from a single particle. Here, we demonstrate that the combination of optical trapping and SERS can be used for the detection and identification of 20 nm polystyrene nanoparticles in plasmonic nanopores. This work is anticipated to contribute to the detection of small bioparticles, optical trapping and nanotribology studies.
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Affiliation(s)
- Sarp Kerman
- imec, Kapeldreef 75, Leuven, B3001, Belgium.
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16
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Suga K, Yoshida T, Ishii H, Okamoto Y, Nagao D, Konno M, Umakoshi H. Membrane Surface-Enhanced Raman Spectroscopy for Sensitive Detection of Molecular Behavior of Lipid Assemblies. Anal Chem 2015; 87:4772-80. [DOI: 10.1021/ac5048532] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Keishi Suga
- Division
of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan
| | - Tomohiro Yoshida
- Division
of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan
| | - Haruyuki Ishii
- Department
of Chemical Engineering, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Yukihiro Okamoto
- Division
of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan
| | - Daisuke Nagao
- Department
of Chemical Engineering, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Mikio Konno
- Department
of Chemical Engineering, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Hiroshi Umakoshi
- Division
of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan
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17
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Bailey MR, Pentecost AM, Selimovic A, Martin RS, Schultz ZD. Sheath-flow microfluidic approach for combined surface enhanced Raman scattering and electrochemical detection. Anal Chem 2015; 87:4347-55. [PMID: 25815795 PMCID: PMC4415045 DOI: 10.1021/acs.analchem.5b00075] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The combination of hydrodynamic focusing with embedded capillaries in a microfluidic device is shown to enable both surface enhanced Raman scattering (SERS) and electrochemical characterization of analytes at nanomolar concentrations in flow. The approach utilizes a versatile polystyrene device that contains an encapsulated microelectrode and fluidic tubing, which is shown to enable straightforward hydrodynamic focusing onto the electrode surface to improve detection. A polydimethyslsiloxane (PDMS) microchannel positioned over both the embedded tubing and SERS active electrode (aligned ∼200 μm from each other) generates a sheath flow that confines the analyte molecules eluting from the embedded tubing over the SERS electrode, increasing the interaction between the Riboflavin (vitamin B2) and the SERS active electrode. The microfluidic device was characterized using finite element simulations, amperometry, and Raman experiments. This device shows a SERS and amperometric detection limit near 1 and 100 nM, respectively. This combination of SERS and amperometry in a single device provides an improved method to identify and quantify electroactive analytes over either technique independently.
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Affiliation(s)
- Matthew R Bailey
- †University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, Indiana 46556, United States
| | - Amber M Pentecost
- ‡Saint Louis University, Department of Chemistry, St. Louis, Missouri 63103, United States
| | - Asmira Selimovic
- ‡Saint Louis University, Department of Chemistry, St. Louis, Missouri 63103, United States
| | - R Scott Martin
- ‡Saint Louis University, Department of Chemistry, St. Louis, Missouri 63103, United States
| | - Zachary D Schultz
- †University of Notre Dame, Department of Chemistry and Biochemistry, Notre Dame, Indiana 46556, United States
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18
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Asiala S, Schultz ZD. Surface enhanced Raman correlation spectroscopy of particles in solution. Anal Chem 2014; 86:2625-32. [PMID: 24502388 PMCID: PMC3966183 DOI: 10.1021/ac403882h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 02/06/2014] [Indexed: 01/26/2023]
Abstract
Surface enhanced Raman correlation spectroscopy (SERCS) is shown as a label-free, chemically specific method for monitoring individual polymer beads and lipid vesicles interacting with a 2-D planar surface enhanced Raman (SERS) substrate in solution. The enhancement afforded by the SERS substrate allows for spectral data to be acquired in series at rates between 31 and 83 Hz. Auto- and cross-correlation of spectral data facilitates the measurement of diffusion constants for particles ranging in radius from 50 to 500 nm while discriminating signal associated with the target analyte from extraneous fluctuations. The measured diffusion coefficients are on the order of 10(-10)-10(-11) cm(2)/s, a factor of 40 times slower than predicted from the Stokes-Einstein equation, suggesting that particles are experiencing hindered diffusion at the surface. The enhanced signals appear to originate from particles less than 5 nm of the SERS substrate, consistent with adsorption to the surface. This work provides a means to measure and monitor surface interactions and demonstrates the utility and limits of SERS detection in solution over planar SERS substrates.
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Affiliation(s)
- Steven
M. Asiala
- Department of Chemistry and
Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Zachary D. Schultz
- Department of Chemistry and
Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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19
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Negri P, Jacobs KT, Dada OO, Schultz ZD. Ultrasensitive surface-enhanced Raman scattering flow detector using hydrodynamic focusing. Anal Chem 2013; 85:10159-66. [PMID: 24074461 DOI: 10.1021/ac401537k] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Label-free, chemical specific detection in flow is important for high throughput characterization of analytes in applications such as flow injection analysis, electrophoresis, and chromatography. We have developed a surface-enhanced Raman scattering (SERS) flow detector capable of ultrasensitive optical detection on the millisecond time scale. The device employs hydrodynamic focusing to improve SERS detection in a flow channel where a sheath flow confines analyte molecules eluted from a fused silica capillary over a planar SERS-active substrate. Increased analyte interactions with the SERS substrate significantly improve detection sensitivity. The performance of this flow detector was investigated using a combination of finite element simulations, fluorescence imaging, and Raman experiments. Computational fluid dynamics based on finite element analysis was used to optimize the flow conditions. The modeling indicates that a number of factors, such as the capillary dimensions and the ratio of the sheath flow to analyte flow rates, are critical for obtaining optimal results. Sample confinement resulting from the flow dynamics was confirmed using wide-field fluorescence imaging of rhodamine 6G (R6G). Raman experiments at different sheath flow rates showed increased sensitivity compared with the modeling predictions, suggesting increased adsorption. Using a 50 ms acquisition, a sheath flow rate of 180 μL/min, and a sample flow rate of 5 μL/min, a linear dynamic range from nanomolar to micromolar concentrations of R6G with a limit of detection (LOD) of 1 nM is observed. At low analyte concentrations, rapid analyte desorption is observed, enabling repeated and high-throughput SERS detection. The flow detector offers substantial advantages over conventional SERS-based assays such as minimal sample volumes and high detection efficiency.
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Affiliation(s)
- Pierre Negri
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana, 46556 United States
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