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Czaja M, Chachaj-Brekiesz A, Skirlińska-Nosek K, Szajna K, Sofińska K, Lupa D, Kobierski J, Wnętrzak A, Szymoński M, Lipiec E. Fabrication of plasmonic probes for reproducible nanospectroscopic investigation of lipid monolayers - The electrochemical etching with DC-pulsed voltage. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 316:124323. [PMID: 38692104 DOI: 10.1016/j.saa.2024.124323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/12/2024] [Accepted: 04/21/2024] [Indexed: 05/03/2024]
Abstract
Tip-enhanced Raman spectroscopy (TERS) is a label-free analytical technique that characterizes molecular systems, potentially even with a nanometric resolution. In principle, the metallic plasmonic probe is illuminated with a laser beam generating the localized surface plasmons, which induce a strong local electric field enhancement in close proximity to the probe. Such field enhancement improves the Raman scattering cross-section from the sample volume localized near the probe apex. TERS provides a high spatial resolution and a great sensitivity, however, it is rather rarely used due to technical limitations causing unstable enhancement and the relative lack of data reproducibility. Despite many scientific efforts for the fabrication of effective TER probes providing robust TER enhancement still requires further investigations. In this work, we explore new possibilities based on preparation of scanning tunnelling microscopy (STM) plasmonic probes, since by nature of the tunnelling effect, they potentially could offer a very high spatial resolution in STM guided TERS experiments. Here we compare two methods of STM-TERS probe preparation for effective spectra acquisition. Our results strongly indicate that an application of square pulse voltage upon the etching procedure significantly improves the quality of the TER data over those obtained with a constant voltage one. To demonstrate the efficiency of our probes we present the results of hyperspectral TER mapping of the 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) monolayer deposited on an ultra-pure and atomically flat gold substrate.
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Affiliation(s)
- Michał Czaja
- Jagiellonian University, Faculty of Physics, Astronomy, and Applied Computer Science, M. Smoluchowski Institute of Physics, Łojasiewicza 11, Kraków 30-348, Poland; Jagiellonian University, Doctoral School of Exact and Natural Sciences, Kraków 30-387, Poland
| | - Anna Chachaj-Brekiesz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, Kraków 30-387, Poland
| | - Katarzyna Skirlińska-Nosek
- Jagiellonian University, Faculty of Physics, Astronomy, and Applied Computer Science, M. Smoluchowski Institute of Physics, Łojasiewicza 11, Kraków 30-348, Poland; Jagiellonian University, Doctoral School of Exact and Natural Sciences, Kraków 30-387, Poland
| | - Konrad Szajna
- Jagiellonian University, Faculty of Physics, Astronomy, and Applied Computer Science, M. Smoluchowski Institute of Physics, Łojasiewicza 11, Kraków 30-348, Poland
| | - Kamila Sofińska
- Jagiellonian University, Faculty of Physics, Astronomy, and Applied Computer Science, M. Smoluchowski Institute of Physics, Łojasiewicza 11, Kraków 30-348, Poland
| | - Dawid Lupa
- Jagiellonian University, Faculty of Physics, Astronomy, and Applied Computer Science, M. Smoluchowski Institute of Physics, Łojasiewicza 11, Kraków 30-348, Poland
| | - Jan Kobierski
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Pharmaceutical Biophysics, Medyczna 9, Kraków 30-688, Poland
| | - Anita Wnętrzak
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, Kraków 30-387, Poland
| | - Marek Szymoński
- Jagiellonian University, Faculty of Physics, Astronomy, and Applied Computer Science, M. Smoluchowski Institute of Physics, Łojasiewicza 11, Kraków 30-348, Poland
| | - Ewelina Lipiec
- Jagiellonian University, Faculty of Physics, Astronomy, and Applied Computer Science, M. Smoluchowski Institute of Physics, Łojasiewicza 11, Kraków 30-348, Poland.
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2
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Gao Y, Zheng P, Meng ZD, Wang HL, You EM, Zhong JH, Tian ZQ, Wang L, He H. Fast Nano-IR Hyperspectral Imaging Empowered by Large-Dataset-Free Miniaturized Spatial-Spectral Network. Anal Chem 2024; 96:9610-9620. [PMID: 38822784 DOI: 10.1021/acs.analchem.4c01211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2024]
Abstract
The emerging field of nanoscale infrared (nano-IR) offers label-free molecular contrast, yet its imaging speed is limited by point-by-point traverse acquisition of a three-dimensional (3D) data cube. Here, we develop a spatial-spectral network (SS-Net), a miniaturized deep-learning model, together with compressive sampling to accelerate the nano-IR imaging. The compressive sampling is performed in both the spatial and spectral domains to accelerate the imaging process. The SS-Net is trained to learn the mapping from small nano-IR image patches to the corresponding spectra. With this elaborated mapping strategy, the training can be finished quickly within several minutes using the subsampled data, eliminating the need for a large-labeled dataset of common deep learning methods. We also designed an efficient loss function, which incorporates the image and spectral similarity to enhance the training. We first validate the SS-Net on an open stimulated Raman-scattering dataset; the results exhibit the potential of 10-fold imaging speed improvement with state-of-the-art performance. We then demonstrate the versatility of this approach on atomic force microscopy infrared (AFM-IR) microscopy with 7-fold imaging speed improvement, even on nanoscale Fourier transform infrared (nano-FTIR) microscopy with up to 261.6 folds faster imaging speed. We further showcase the generalization of this method on AFM-force volume-based multiparametric nanoimaging. This method establishes a paradigm for rapid nano-IR imaging, opening new possibilities for cutting-edge research in materials, photonics, and beyond.
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Affiliation(s)
- Yun Gao
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
| | - Peng Zheng
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
| | - Zhao-Dong Meng
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Hai-Long Wang
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361102, China
| | - En-Ming You
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- School of Ocean Information Engineering, Jimei University, Xiamen 361021, China
| | - Jin-Hui Zhong
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhong-Qun Tian
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Lei Wang
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
| | - Hao He
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Li J, Jahng J, Ma X, Liang J, Zhang X, Min Q, Wang XL, Chen S, Lee ES, Xia XH. Surface-phonon-polariton-enhanced photoinduced dipole force for nanoscale infrared imaging. Natl Sci Rev 2024; 11:nwae101. [PMID: 38698902 PMCID: PMC11065349 DOI: 10.1093/nsr/nwae101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/12/2024] [Accepted: 03/12/2024] [Indexed: 05/05/2024] Open
Abstract
The photoinduced dipole force (PiDF) is an attractive force arising from the Coulombic interaction between the light-induced dipoles on the illuminated tip and the sample. It shows extreme sample-tip distance and refractive index dependence, which is promising for nanoscale infrared (IR) imaging of ultrathin samples. However, the existence of PiDF in the mid-IR region has not been experimentally demonstrated due to the coexistence of photoinduced thermal force (PiTF), typically one to two orders of magnitude higher than PiDF. In this study, we demonstrate that, with the assistance of surface phonon polaritons, the PiDF of c-quartz can be enhanced to surpass its PiTF, enabling a clear observation of PiDF spectra reflecting the properties of the real part of permittivity. Leveraging the detection of the PiDF of phonon polaritonic substrate, we propose a strategy to enhance the sensitivity and contrast of photoinduced force responses in transmission images, facilitating the precise differentiation of the heterogeneous distribution of ultrathin samples.
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Affiliation(s)
- Jian Li
- State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Junghoon Jahng
- Hyperspectral Nano-Imaging Team, Korea Research Institute of Standards and Science, Daejeon 34113, South Korea
| | - Xuezhi Ma
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore 138634, Singapore
| | - Jing Liang
- State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xue Zhang
- State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Qianhao Min
- State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xiao-Liang Wang
- State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Shuangjun Chen
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China
| | - Eun Seong Lee
- Hyperspectral Nano-Imaging Team, Korea Research Institute of Standards and Science, Daejeon 34113, South Korea
| | - Xing-Hua Xia
- State Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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4
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Li J, Liang J, Lan MH, Xia XH. Atomic force microscopy-based nanoscale infrared techniques for liquid environments. Sci Bull (Beijing) 2024; 69:151-153. [PMID: 37993337 DOI: 10.1016/j.scib.2023.11.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Affiliation(s)
- Jian Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jing Liang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Mu-Hao Lan
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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5
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Li J, Liang J, Lan MH, Xia XH. Atomic Force Microscopy-Based Nanoscale Infrared Techniques for Catalysis. J Phys Chem Lett 2023; 14:11318-11323. [PMID: 38064367 DOI: 10.1021/acs.jpclett.3c02937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Atomic force microscopy (AFM)-based nanoscale infrared (nano-IR) techniques have found extensive application in the fields of chemistry, physics, and materials science, enabling the visualization of nanoscale features that surpass the optical diffraction limit. More recently, tentative investigations have been conducted into the use of these techniques in the field of catalysis, particularly in studying interfacial processes involving molecular monolayer samples. IR nanoimaging and nanospectroscopy offer unique perspectives on catalytic processes. Considering the specific characteristics of catalytic processes, this Perspective highlights the need for and reviews the current status of AFM-based nano-IR techniques for catalysis investigations, which aims to contribute to a deeper understanding of the nanoscale mechanisms underlying the catalytic processes.
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Affiliation(s)
- Jian Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jing Liang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Mu-Hao Lan
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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6
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Xie Q, Xu XG. What Do Different Modes of AFM-IR Mean for Measuring Soft Matter Surfaces? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17593-17599. [PMID: 38014870 PMCID: PMC10720454 DOI: 10.1021/acs.langmuir.3c02950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/29/2023]
Abstract
In the past decade, rapidly emerging atomic force microscopy-based photothermal infrared microscopy (AFM-IR) techniques have routinely delivered surface chemical imaging with tens of nanometers spatial resolution. The commercial availability of AFM-IR instruments has accelerated their popularity among soft matter and surface science communities. Various AFM-IR modes exist with different characteristics. In this Perspective, we discuss the challenges and opportunities associated with many AFM-IR modes, clarifying the possible confusion arising from terminologies and describing the possible benefits of using multiple AFM-IR modes for a better understanding of the nanoscale composition organization of the interface.
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Affiliation(s)
- Qing Xie
- Department of Chemistry, Lehigh University, 6 E Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Xiaoji G. Xu
- Department of Chemistry, Lehigh University, 6 E Packer Avenue, Bethlehem, Pennsylvania 18015, United States
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7
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V. D. dos Santos AC, Hondl N, Ramos-Garcia V, Kuligowski J, Lendl B, Ramer G. AFM-IR for Nanoscale Chemical Characterization in Life Sciences: Recent Developments and Future Directions. ACS MEASUREMENT SCIENCE AU 2023; 3:301-314. [PMID: 37868358 PMCID: PMC10588935 DOI: 10.1021/acsmeasuresciau.3c00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/30/2023] [Accepted: 05/30/2023] [Indexed: 10/24/2023]
Abstract
Despite the ubiquitous absorption of mid-infrared (IR) radiation by virtually all molecules that belong to the major biomolecules groups (proteins, lipids, carbohydrates, nucleic acids), the application of conventional IR microscopy to the life sciences remained somewhat limited, due to the restrictions on spatial resolution imposed by the diffraction limit (in the order of several micrometers). This issue is addressed by AFM-IR, a scanning probe-based technique that allows for chemical analysis at the nanoscale with resolutions down to 10 nm and thus has the potential to contribute to the investigation of nano and microscale biological processes. In this perspective, in addition to a concise description of the working principles and operating modes of AFM-IR, we present and evaluate the latest key applications of AFM-IR to the life sciences, summarizing what the technique has to offer to this field. Furthermore, we discuss the most relevant current limitations and point out potential future developments and areas for further application for fruitful interdisciplinary collaboration.
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Affiliation(s)
| | - Nikolaus Hondl
- Institute
of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Victoria Ramos-Garcia
- Health
Research Institute La Fe, Avenida Fernando Abril Martorell 106, 46026 Valencia, Spain
| | - Julia Kuligowski
- Health
Research Institute La Fe, Avenida Fernando Abril Martorell 106, 46026 Valencia, Spain
| | - Bernhard Lendl
- Institute
of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Georg Ramer
- Institute
of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
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8
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Xu XG. Multimodal Nano-IR through Peak Force Infrared (PFIR) Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:563. [PMID: 37613309 DOI: 10.1093/micmic/ozad067.269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Xiaoji G Xu
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania, United States
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9
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Wang H, Lee D, Wei L. Toward the Next Frontiers of Vibrational Bioimaging. CHEMICAL & BIOMEDICAL IMAGING 2023; 1:3-17. [PMID: 37122829 PMCID: PMC10131268 DOI: 10.1021/cbmi.3c00004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 05/02/2023]
Abstract
Chemical imaging based on vibrational contrasts can extract molecular information entangled in complex biological systems. To this end, nonlinear Raman scattering microscopy, mid-infrared photothermal (MIP) microscopy, and atomic force microscopy (AFM)-based force-detected photothermal microscopies are emerging with better chemical sensitivity, molecular specificity, and spatial resolution than conventional vibrational methods. Their utilization in bioimaging applications has provided biological knowledge in unprecedented detail. This Perspective outlines key methodological developments, bioimaging applications, and recent technical innovations of the three techniques. Representative biological demonstrations are also highlighted to exemplify the unique advantages of obtaining vibrational contrasts. With years of effort, these three methods compose an expanding vibrational bioimaging toolbox to tackle specific bioimaging needs, benefiting many biological investigations with rich information in both label-free and labeling manners. Each technique will be discussed and compared in the outlook, leading to possible future directions to accommodate growing needs in vibrational bioimaging.
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Affiliation(s)
- Haomin Wang
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Dongkwan Lee
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Lu Wei
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
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10
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Dorsa A, Xie Q, Wagner M, Xu XG. Lock-in amplifier based peak force infrared microscopy. Analyst 2023; 148:227-232. [PMID: 36537473 DOI: 10.1039/d2an01103d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nanoscale infrared (nano-IR) microscopy enables label-free chemical imaging with a spatial resolution below Abbe's diffraction limit through the integration of atomic force microscopy and infrared radiation. Peak force infrared (PFIR) microscopy is one of the emerging nano-IR methods that provides non-destructive multimodal chemical and mechanical characterization capabilities using a straightforward photothermal signal generation mechanism. PFIR microscopy has been demonstrated to work for a wide range of heterogeneous samples, and it even allows operation in the fluid phase. However, the current PFIR microscope requires customized hardware configuration and software programming for real-time signal acquisition and processing, which creates a high barrier to PFIR implementation. In this communication, we describe a type of lock-in amplifier-based PFIR microscopy that can be assembled with generic, commercially available equipment without special hardware or software programming. We demonstrate this method on soft matters of structured polymer blends and blocks, as well as biological cells of E. coli. The lock-in amplifier-based PFIR reduces the entry barrier for PFIR microscopy and makes it a competitive nano-IR method for new users.
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Affiliation(s)
- Andrea Dorsa
- Department of Chemistry, Lehigh University, 6 E Packer Ave., Bethlehem, PA, 18015, USA.
| | - Qing Xie
- Department of Chemistry, Lehigh University, 6 E Packer Ave., Bethlehem, PA, 18015, USA.
| | - Martin Wagner
- Bruker Nano Surface, 112 Robin Hill Road, Santa Barbara, CA, 93117 USA
| | - Xiaoji G Xu
- Department of Chemistry, Lehigh University, 6 E Packer Ave., Bethlehem, PA, 18015, USA.
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11
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Su HS, Chang X, Xu B. Surface-enhanced vibrational spectroscopies in electrocatalysis: Fundamentals, challenges, and perspectives. CHINESE JOURNAL OF CATALYSIS 2022. [DOI: 10.1016/s1872-2067(22)64157-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Wang L, Wang H, Xu XG. Principle and applications of peak force infrared microscopy. Chem Soc Rev 2022; 51:5268-5286. [PMID: 35703031 DOI: 10.1039/d2cs00096b] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Peak force infrared (PFIR) microscopy is an emerging atomic force microscopy (AFM)-based infrared microscopy that bypasses Abbe's diffraction limit on spatial resolution. The PFIR microscopy utilizes a nanoscopically sharp AFM tip to mechanically detect the tip-enhanced infrared photothermal response of the sample in the time domain. The time-gated mechanical signals of cantilever deflections transduce the infrared absorption of the sample, delivering infrared imaging and spectroscopy capability at sub 10 nm spatial resolution. Both the infrared absorption response and mechanical properties of the sample are obtained in parallel while preserving the surface integrity of the sample. This review describes the constructions of the PFIR microscope and several variations, including multiple-pulse excitation, total internal reflection geometry, dual-color configuration, liquid-phase operations, and integrations with simultaneous surface potential measurement. Representative applications of PFIR microscopy are also included in this review. In the outlook section, we lay out several future directions of innovations in PFIR microscopy and applications in chemical and material research.
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Affiliation(s)
- Le Wang
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA.
| | - Haomin Wang
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA.
| | - Xiaoji G Xu
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA.
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13
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Sifat AA, Jahng J, Potma EO. Photo-induced force microscopy (PiFM) - principles and implementations. Chem Soc Rev 2022; 51:4208-4222. [PMID: 35510630 DOI: 10.1039/d2cs00052k] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Photo-induced force microscopy (PiFM) is a scan probe technique that offers images with spectroscopic contrast at a spatial resolution in the nanometer range. PiFM utilizes the non-propagating, enhanced near field at the apex of a sharp tip to locally induce a polarization in the sample, which in turn produces an additional force acting on the cantilevered tip. This photo-induced force, though in the pN range or less, can be extracted from the oscillation properties of the cantilever, thus enabling the generation of photo-induced force maps. Since its inception in 2010, the PiFM technique has grown into a useful nano-spectrocopic tool that has expanded its reach in terms of imaging capabilities and applications. In this review, we present various technical implementations of the PiFM approach. In addition, we discuss the physical origin of the PiFM signal, highlighting the contributions from dipole-dipole forces as well as forces that derive from photo-thermal processes.
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Affiliation(s)
- Abid Anjum Sifat
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, USA
| | - Junghoon Jahng
- Hyperspectral Nano-imaging Lab, Korea Research Institute of Standards and Science, Daejeon 34113, South Korea
| | - Eric O Potma
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, USA.,Department of Chemistry, University of California, Irvine, CA, USA.
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14
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Abstract
Peak force infrared (PFIR) microscopy achieves nanoscale infrared imaging at sub-10 nm spatial resolution through photothermal mechanical detection of atomic force microscopy (AFM). However, it suffers from a major limitation that only one infrared frequency can be scanned for an AFM frame at a time. To overcome this limitation, we report here dual-color PFIR microscopy that enables simultaneous imaging at two infrared frequencies. This dual-color PFIR microscopy bypasses the limitations of frame drift and distortion of AFM when comparing two images of different infrared frequencies. We benchmark the performance and spatial resolution of this method using structured polymers exhibiting phase separation. We further demonstrate the application of this technique in imaging biological samples by mapping the cell wall of Escherichia coli (E. coli) bacteria. The presence of a bacterial outer membrane was detected without extrinsic labels. This dual-color PFIR microscopy enables simultaneous nondestructive chemical nanoimaging of multiple chemical components and will be useful for potential applications such as in situ dual-channel monitoring of chemical reactions.
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Affiliation(s)
- Qing Xie
- Department of Chemistry, Lehigh University, 6 E. Packer Ave., Bethlehem, Pennsylvania 18015, United States
| | - Jared Wiemann
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Yan Yu
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Xiaoji G Xu
- Department of Chemistry, Lehigh University, 6 E. Packer Ave., Bethlehem, Pennsylvania 18015, United States
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15
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Wang H, Xie Q, Xu XG. Super-resolution mid-infrared spectro-microscopy of biological applications through tapping mode and peak force tapping mode atomic force microscope. Adv Drug Deliv Rev 2022; 180:114080. [PMID: 34906646 DOI: 10.1016/j.addr.2021.114080] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/15/2021] [Accepted: 12/06/2021] [Indexed: 11/19/2022]
Abstract
Small biomolecules at the subcellular level are building blocks for the manifestation of complex biological activities. However, non-intrusive in situ investigation of biological systems has been long daunted by the low spatial resolution and poor sensitivity of conventional light microscopies. Traditional infrared (IR) spectro-microscopy can enable label-free visualization of chemical bonds without extrinsic labeling but is still bound by Abbe's diffraction limit. This review article introduces a way to bypass the optical diffraction limit and improve the sensitivity for mid-IR methods - using tip-enhanced light nearfield in atomic force microscopy (AFM) operated in tapping and peak force tapping modes. Working principles of well-established scattering-type scanning near-field optical microscopy (s-SNOM) and two relatively new techniques, namely, photo-induced force microscopy (PiFM) and peak force infrared (PFIR) microscopy, will be briefly presented. With ∼ 10-20 nm spatial resolution and monolayer sensitivity, their recent applications in revealing nanoscale chemical heterogeneities in a wide range of biological systems, including biomolecules, cells, tissues, and biomaterials, will be reviewed and discussed. We also envision several future improvements of AFM-based tapping and peak force tapping mode nano-IR methods that permit them to better serve as a versatile platform for uncovering biological mechanisms at the fundamental level.
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Affiliation(s)
- Haomin Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Qing Xie
- Department of Chemistry, Lehigh University, Bethlehem, PA 18015, USA
| | - Xiaoji G Xu
- Department of Chemistry, Lehigh University, Bethlehem, PA 18015, USA.
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16
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González-Fialkowski JM, Wang L, Li Y, Xu XG. Nano-Chemical and Mechanical Mapping of Fine and Ultrafine Indoor Aerosols with Peak Force Infrared Microscopy. Anal Chem 2021; 93:16845-16852. [PMID: 34871494 DOI: 10.1021/acs.analchem.1c03659] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Indoor aerosols can adversely affect human health as we increasingly spend more time indoors. One of the aerosol research challenges is measuring fine and ultrafine aerosol particles with nanoscale dimensions. Spectroscopic tools, often diffraction-limited, cannot access the intra-particle heterogeneity. In this work, we extend the non-invasive nanoscopy method of peak force infrared (PFIR) microscopy to study indoor aerosols. Laboratory-generated fine bioaerosols were collected after filtration with a surgical face mask to serve as a benchmark sample, followed by a variety of field-collected indoor aerosols with and without the filtration of a facemask. A general heterogeneity is observed in individual aerosol particles, despite their nanoscale dimension. The presence of protein, triglycerides, and salt is detected through chemical and mechanical mapping. The PFIR microscopy is suitable to identify the composition of fine and ultrafine aerosols. Its application is particularly meaningful for understanding the particle structure to reduce aerosol-related transmission of diseases.
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Affiliation(s)
| | - Le Wang
- Department of Chemistry, Lehigh University, 6 E Packer Avenue, Bethlehem 18015, Pennsylvania
| | - Yongjie Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Avenida da Universidade, Taipa, Macau 999078, China
| | - Xiaoji G Xu
- Department of Chemistry, Lehigh University, 6 E Packer Avenue, Bethlehem 18015, Pennsylvania
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