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Stimulated Raman scattering tomography for rapid three-dimensional chemical imaging of cells and tissue

Advanced Photonics 2024年第2期6卷 20-31页

作者： Weiqi Wang Zhiwei Huang National University of singapore College of Design and EngineeringOptical Bioimaging LaboratoryDepartment of Biomedical EngineeringSingapore

Three-dimensional(3D)imaging is essential for understanding intricate biological and biomedical systems,yet live cell and tissue imaging applications still face challenges due to constrained imaging speed and strong scattering in turbid media.Here,we present a unique phase-modulated stimulated Raman scattering tomography(PM-SRST)technique to achieve rapid label-free 3D chemical imaging in cells and tissue.To accomplish PM-SRST,we utilize a spatial light modulator to electronically manipulate the focused Stokes beam along the needle Bessel pump beam for SRS tomography without the need for mechanical z scanning.We demonstrate the rapid 3D imaging capability of PM-SRST by real-time monitoring of 3D Brownian motion of polystyrene beads in water with 8.5 Hz volume rate,as well as the instant biochemical responses to acetic acid stimulants in MCF-7 cells.Further,combining the Bessel pump beam with a longer wavelength Stokes beam(NIR-II window)provides a superior scattering resilient ability in PM-SRST,enabling rapid tomography in deeper tissue areas.The PM-SRST technique providestwofold enhancement in imaging depth in highly scattering media(e.g.,polymer beads phantom and biotissue like porcine skin and brain tissue)compared with conventional point-scan SRS.We also demonstrate the rapid 3D imaging ability of PM-SRST by observing the dynamic diffusion and uptake processes of deuterium oxide molecules into plant roots.The rapid PM-SRST developed can be used to facilitate label-free 3D chemical imaging of metabolic activities and functional dynamic processes of drug delivery and therapeutics in live cells and tissue.

关键词： stimulated Raman scattering tomography deep tissue Raman imaging spatial light modulation

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Mitochondria-specific near-infrared photoactivation of peroxynitrite upconversion luminescent nanogenerator for precision cancer gas therapy

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Acta Pharmaceutica Sinica B 2024年第1期14卷 378-391页

作者： Hui Yu Aliya Tiemuer Xufeng Yao Mingyuan Zuo Hai-Yan Wang Yi Liu Xiaoyuan Chen Department of Biomedical Engineering School of EngineeringChina Pharmaceutical UniversityNanjing 211198China School of Mechanical Engineering Southeast UniversityNanjing 211189China Departments of Diagnostic Radiology SurgeryChemical and Biomolecular Engineeringand Biomedical EngineeringYong Loo Lin School of Medicine and College of Design and EngineeringNational University of SingaporeSingapore 119074Singapore Clinical Imaging Research Centre Centre for Translational MedicineYong Loo Lin School of MedicineNational University of SingaporeSingapore 117599Singapore Nanomedicine Translational Research Program Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117597Singapore Institute of Molecular and Cell Biology Agency for ScienceTechnologyand Research(A*STAR)ProteosSingapore 138673Singapore

Gas therapy is emerging as a highly promising therapeutic strategy for cancer treatment.However,there are limitations,including the lack of targeted subcellular organelle accuracy and spatiotemporal release precision,associated with gas therapy.In this study,we developed a series of photoactivatable nitric oxide(NO)donors NRh-R-NO(R=Me,Et,Bn,iPr,and Ph)based on an N-nitrosated upconversion luminescent rhodamine scaffold.Under the irradiation of 808 nm light,only NRh-Ph-NO could effectively release NO and NRh-Ph with a significant turn-on frequency upconversion luminescence(FUCL)signal at 740 nm,ascribed to lower N-N bond dissociation energy.We also investigated the involved multistage near-infrared-controlled cascade release of gas therapy,including the NO released from NRh-Ph-NO along with one NRh-Ph molecule generation,the superoxide anion O_(2)^(⋅−)produced by the photodynamic therapy(PDT)effect of NRh-Ph,and highly toxic peroxynitrite anion(ONOO‒)generated from the co-existence of NO and O_(2)^(⋅−).After mild nano-modification,the nanogenerator(NRh-Ph-NO NPs)empowered with superior biocompatibility could target mitochondria.Under an 808 nm laser irradiation,NRh-Ph-NO NPs could induce NO/ROS to generate RNS,causing a decrease in the mitochondrial membrane potential and initiating apoptosis by caspase-3 activation,which further induced tumor immunogenic cell death(ICD).In vivo therapeutic results of NRh-Ph-NO NPs showed augmented RNS-potentiated gas therapy,demonstrating excellent biocompatibility and effective tumor inhibition guided by real-time FUCL imaging.Collectively,this versatile strategy defines the targeted RNS-mediated cancer therapy.

关键词： Near infrared Photo-triggered Mitochondrion Upconversion luminescent bioimaging Peroxynitrite Nanogenerator Gas therapy In vivo

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The synthesis of fluorescent nanoclusters based on the etching reaction

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Nano Research 2024年第5期17卷 4631-4638页

作者： Hongbin Lin Yitao Cao Qiaofeng Yao Tiankai Chen Huiting Shan Jianping Xie Joint School of National University of singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117585Singapore National and Local Joint Engineering Research Center of MPTES in High Energy and Safety LIBs Engineering Research Center of MTEES(Ministry of Education)and Key Laboratory of ETESPG(GHEI)South China Normal UniversityGuangzhou 510006China Tianjin Key Laboratory of Molecular Optoelectronic Sciences Key Laboratory of Integrated Organic CircuitsMinistry of EducationDepartment of ChemistrySchool of ScienceTianjin UniversityTianjin 300072China

Thiolate-protected atomically precise nanoclusters(NCs)demonstrate a series of unique luminescent characteristics attributed to their various peculiar electronic structures.Therefore,fluorescent NCs present extraordinary practical values in biosensing and bioimaging research fields.Nevertheless,restricted by the types of fluorescent NCs,there are great difficulties in promoting the development of NCs in fluorescent research areas.As a result,it is of significant necessity for researchers to develop new synthetic pathways to produce high-quality fluorescent NCs.According to the analysis about the structural characteristics of fluorescent NCs,some general features like longer motif and higher ligand-to-metal ratio can be found,consistent to some presented regularities in etching reaction.Consequently,in this work,we used Au_(25)(MHA)_(18)(MHA=6-mercaptohexanoic acid)as a model nanocluster and utilized the etching reaction to systematically explore etching products and their corresponding luminescent properties.Moreover,we also identified three main reaction processes in the entire etching reaction process,which can generate new metal nanocluster species with various fluorescent properties.Hence,the etching reaction will provide a good platform to produce new luminescent metal NC species.

关键词： etching reaction metal nanoclusters fluorescent properties fluorescent conversion

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Classification of Plant Endogenous States Using Machine Learning-Derived Agricultural Indices

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Plant Phenomics 2023年第3期5卷 474-483页

作者： Sally Shuxian Koh Kapil Dev Javier Jingheng Tan Valerie Xinhui Teo Shuyan Zhang Dinish U.S. Malini Olivo Daisuke Urano Temasek Life Sciences Laboratory National University of SingaporeSingaporeSingapore Department of Biological Sciences National University of SingaporeSingaporeSingapore Translational Biophotonics Laboratory Institute of Bioengineering and BioimagingAgency for ScienceTechnology and Research(A*STAR)SingaporeSingapore Institute of Materials Research and Engineering(IMRE) Agency for ScienceTechnology and Research(A*STAR)SingaporeSingapore

Leaf color patterns vary depending on leaf age,pathogen infection,and environmental and nutritional stresses;thus,they are widely used to diagnose plant health statuses in agricultural fields.The visible-near infrared-shortwave infrared(VIS-NIR-SWIR)sensor measures the leaf color pattern from a wide spectral range with high spectral resolution.However,spectral information has only been employed to understand general plant health statuses(e.g.,vegetation index)or phytopigment contents,rather than pinpointing defects of specific metabolic or signaling pathways in plants.Here,we report feature engineering and machine learning methods that utilize VIS-NIR-SWIR leaf reflectance for robust plant health diagnostics,pinpointing physiological alterations associated with the stress hormone,abscisic acid(ABA).Leaf reflectance spectra of wild-type,ABA2-overexpression,and deficient plants were collected under watered and drought conditions.Drought-and ABA-associated normalized reflectance indices(NRIs)were screened from all possible pairs of wavelength bands.Drought associated NRIs showed only a partial overlap with those related to ABA deficiency,but more NRIs were associated with drought due to additional spectral changes within the NIR wavelength range.Interpretable support vector machine classifiers built with 20 NRIs predicted treatment or genotype groups with an accuracy greater than those with conventional vegetation indices.Major selected NRIs were independent from leaf water content and chlorophyll content,2 well-characterized physiological changes under drought.The screening of NRIs,streamlined with the development of simple classifiers,serves as the most efficient means of detecting reflectance bands that are highly relevant to characteristics of interest.

关键词： drought reflectance indices

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Peptides-modified polystyrene-based polymers as high-performance substrates for the growth and propagation of human embryonic stem cells

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Chinese Chemical Letters 2022年第6期33卷 2901-2905页

作者： Fen Yang Da Zhang Quanming Zhou Mengchu Li Chengliang Xie Shaoyun Li Xuan Wang Wei Wang Ying Guo Qicai Xiao Yong Wang Liqian Gao School of Pharmaceutical Sciences(Shenzhen) Sun Yat-sen UniversityShenzhen 518107China Institute of Bioengineering and bioimaging Singapore 138669Singapore

As human stem cells with the special pluripotency play important roles in the innovative drug discovery and regenerative medicine,development of extracellular matrix(ECM)mimetics or functional materials that can support stem cell growth and propagation is of high significance.Despite numerous efforts spent,one major limitation restricting the wide applications of stem cells to the clinical translation is the lack of efficient strategies for low cost and large-scale stem cell production under xeno-free culture conditions.Herein,we reported a new strategy with peptides-modified polystyrene-based polymers coated onto the surface of coverslips for the growth and reproduction of human embryonic stem cells(h ESCs).The modified peptides are the active parts of proteins which has been shown to contribute to the pluripotent stem cell attachment or proliferation.The peptides were linked to the glass coverslips coated by the polymer materials via chemical crosslinking,and the composite substrates successfully maintain the longterm growth of HUES-7,H7 and DF699.Our study shows that the coating of polystyrene-derived polymer modified by our developed peptides is a good matrix for long-term growth and reproduction of stem cells.This polystyrene-derived polymer substrate can be produced in large scale and stored for a long time.The most important thing is that it can support the growth of undifferentiated human pluripotent stem cells(h PSCs)for more than ten passages,which could provide a new and relatively easy way to amplify h ESCs in vitro.

关键词： Extracellular matrix Stem cell Peptide Coverslip Polystyrene

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DNA-binding proteins studied by mechanical manipulation and AFM imaging of single DNA molecules

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Biophysics Reports 2022年第4期8卷 212-224页

作者： Xiaodan Zhao Xuyao Priscilla Liu Jie Yan Department of Physics National University of Singapore Centre for bioimaging Sciences National University of Singapore Mechanobiology Institute National University of Singapore

The functions of DNA-binding proteins are dependent on protein-induced DNA distortion, the binding preference to special sequences, DNA secondary structures, the binding kinetics and the binding affinity. Recent rapid progress in single-molecule imaging and mechanical manipulation technologies have made it possible to directly probe the DNA binding by proteins, footprint the positions of the bound proteins on DNA, quantify the kinetics and the affinity of protein–DNA interactions, and study the interplay of protein binding with DNA conformation and DNA topology. Here, we review the applications of an integrated approach where the single-DNA imaging using atomic force microscopy and the mechanical manipulation of single DNA molecules are combined to study the DNA–protein interactions. We also provide our views on how these findings yield new insights into understanding the roles of several essential DNA architectural proteins.

关键词： AFM imaging Single-molecule manipulation Magnetic tweezers Optical tweezers DNA-protein interactions DNA supercoiling DNA distortion

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Micro-and nano-fiber probes for optical sensing,imaging,and stimulation in biomedical applications

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Photonics Research 2020年第11期8卷 1703-1724页

作者： Xia Yu Shuyan Zhang Malini Olivo Nanxi Li School of Instrumentation and Optoelectronic Engineering Beihang UniversityBeijing 100083China singapore bioimaging consortium Agency for ScienceTechnologyand Research(A*STAR)Singapore 138667Singapore Institute of Microelectronics Agency for ScienceTechnologyand Research(A*STAR)Singapore 138634Singapore

The flexibile nature of optical fiber enables it to offer remote-access capabilities,which could be used in many biomedical applications.This review focuses on different micro-and nano-structured fiber probes for applications in biosensing,imaging,and stimulations.The modifications to fiber could extend design freedom from waveguide optimization to functional material integration.Fiber probes with optimized waveguide structures or integrated functional materials could achieve enhanced optical mode interaction with biosamples,and hence obtain ultrasensitive biosensors with a remarkably low limit of detection.Furthermore,bioimaging with a high spatial resolution can be obtained by engineering dispersion and nonlinearity of light propagation in the fiber core or designing a metal-coated tapered fiber tip with a sub-wavelength aperture.Flat metasurfaces can be assembled on a fiber tip to achieve a large depth of focus and remove aberrations.Fiber is also a compact solution to realize the precise delivery of light for in vivo applications,such as deep brain stimulation.The optical beam size,shape,and direction could be steered by the probe parameters.Micro-and nano-technologies integrated with fiber contribute to various approaches to further improve detection limit,sensitivity,optical resolution,imaging depth,and stimulation precision.

关键词： fiber waveguide stimulation

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Polariton lasing in Mie-resonant perovskite nanocavity

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Opto-Electronic Advances 2024年第4期7卷 27-42页

作者： Mikhail A.Masharin Daria Khmelevskaia Valeriy I.Kondratiev Daria I.Markina Anton D.Utyushev Dmitriy M.Dolgintsev Alexey D.Dmitriev Vanik A.Shahnazaryan Anatoly P.Pushkarev Furkan Isik Ivan V.Iorsh Ivan A.Shelykh Hilmi V.Demir Anton K.Samusev Sergey V.Makarov UNAM-Institute of Materials Science and Nanotechnology National Nanotechnology Research CenterDepartment of Electrical and Electronics EngineeringDepartment of PhysicsBilkent UniversityAnkara 06800Turkey ITMO University School of Physics and EngineeringSt.Petersburg 197101Russia Abrikosov Center for Theoretical Physics MIPTDolgoprudnyiMoscow Region 141701Russia LUMINOUS!Center of Excellence for Semiconductor Lighting and Displays School of Electrical and Electronic EngineeringSchool of Physical and Mathematical SciencesSchool of Materials Science and EngineeringNanyang Technological UniversitySingapore 639798Singapore Department of Physics Engineering Physics and AstronomyQueen’s UniversityKingstonOntario K7L 3N6Canada Science Institute University of IcelandDunhagi 3IS-107ReykjavikIceland Experimentelle Physik 2 Technische Universität DortmundDortmund 44227Germany Qingdao Innovation and Development Center Harbin Engineering UniversityQingdao 266000China

Deeply subwavelength lasers(or nanolasers)are highly demanded for compact on-chip bioimaging and sensing at the nanoscale.One of the main obstacles for the development of single-particle nanolasers with all three dimensions shorter than the emitting wavelength in the visible range is the high lasing thresholds and the resulting overheating.Here we ex-ploit exciton-polariton condensation and mirror-image Mie modes in a cuboid CsPbBr3 nanoparticle to achieve coherent emission at the visible wavelength of around 0.53μm from its ultra-small(≈0.007μm3 or≈λ3/20)semiconductor nanocav-ity.The polaritonic nature of the emission from the nanocavity localized in all three dimensions is proven by direct com-parison with corresponding one-dimensional and two-dimensional waveguiding systems with similar material parameters.Such a deeply subwavelength nanolaser is enabled not only by the high values for exciton binding energy(≈35 meV),re-fractive index(>2.5 at low temperature),and luminescence quantum yield of CsPbBr3,but also by the optimization of po-laritons condensation on the Mie resonances with quality factors improved by the metallic substrate.Moreover,the key parameters for optimal lasing conditions are intermode free spectral range and phonons spectrum in CsPbBr3,which govern polaritons condensation path.Such chemically synthesized colloidal CsPbBr3 nanolasers can be potentially de-posited on arbitrary surfaces,which makes them a versatile tool for integration with various on-chip systems.

关键词： nanolaser perovskite polariton Mie resonance exciton-polariton

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Characterization of amyloid-β precursor protein intracellular domain-associated transcriptional complexes in SH-SY5Y neurocytes

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Neuroscience Bulletin 2012年第3期28卷 259-270页

作者： Wulin Yang Amy Yong Chen Lau Shuizhong Luo Qian Zhu Li Lu School of Biotechnology and Food Engineering Hefei University of TechnologyHefei 230009China Laboratory of Metabolic Medicine Singapore Bioimaging Consortium(SBIC)Agency for ScienceTechnology and Research(A*STAR)Singapore Department of Anatomy Shanxi Medical UniversityTaiyuan 030001China

Objective Alzheimer＇s disease （AD） is one of the major disorders worldwide. Recent research suggests that the amyloid-β precursor protein intracellular domain （AICD） is a potential contributor to AD development and progression. The small AICD is rapidly degraded after processing from the full-length protein. The present study aimed to apply a highly efficient biotinylation approach in vitro to study AICD-associated complexes in neurocytes. Methods By coexpressing Escherichia coli biotin ligase with biotinyl-tagged AICD in the SH-SY5Y neuronal cell line, the effects of AICD overexpression on cell proliferation and apoptosis were analyzed. Besides, AICD-associated nuclear transcriptional complexes were purified and then examined by mass spectrometry. Results Our data showed that AICD overexpression not only affected cell proliferation but also led to apoptosis in differentiated SH-SY5Y cells. Moreover, biotinylation allowed single-step purification of biotinylated AICD-associated complexes from total nuclear extract via high-affinity biotin-streptavidin binding. Following this by mass spectrometry, we identified physically associated proteins, some reported previously and other novel binding partners, CUX1 and SPT5. Conclusion Based on these results, a map of the AICD-associated nuclear interactome was depicted. Specifically, AICD can activate CUX1 transcriptional activity, which may be associated with AICD-dependent neuronal cell death. This work helps to understand the AICD-associated biological events in AD progression and provides novel insights into the development of AD.

关键词： Alzheimer＇s disease amyloid-β precursor protein AICD biotinylation apoptosis

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SURFACE-ENHANCED RAMAN SCATTERING:PRINCIPLES,NANOSTRUCTURES,FABRICATIONS,AND BIOMEDICAL APPLICATIONS

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Journal of Innovative Optical Health Sciences 2008年第2期1卷 267-284页

作者： CLEMENT YUEN WEI ZHENG ZHIWEI HUANG bioimaging Laboratory Department of Bioengineering Faculty of EngineeringNational University of Singapore Singapore 117576

This article gives an overview of the development and applications of the surfaceenhanced Raman scattering(SERS)techniques in biomedicine.We first introduce the fundamental principles of the SERS mechanisms.We also present the different fabrication techniques of SERS nanostructures and substrates.Finally,the importance and potential roles of the SERS nanostructures and substrates in biomedical applications are summarized.

关键词： Surface-enhanced Raman scattering surface plasmon nanotechnology

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