A laser scanning confocal imaging-surface plasmon resonance （LSCI-SPR） instrument integrated with a wavelength-dependent surface plasmon resonance （SPR） sensor and a laser scanning confocal microscopy （LSCM） is ...A laser scanning confocal imaging-surface plasmon resonance （LSCI-SPR） instrument integrated with a wavelength-dependent surface plasmon resonance （SPR） sensor and a laser scanning confocal microscopy （LSCM） is built to detect the bonding process of human IgG and fluorescent-labeled affinity purified antibodies in real time. The shifts of resonant wavelength at different reaction time stages are obtained by SPR, corresponding well with the changes of the fluorescence intensity collected by using LSCM. The instrument shows the merits of the combination and complementation of the SPR and LSCM, with such advantages as quantificational analysis, high spatial resolution and real time monitor, which are of great importance for practical applications in biosensor and life science.展开更多
In this work, we describe an approach of detecting biomarkers by Surface Plasmon Resonance imaging (SPRi) technique in real samples. Two C-Reactive Protein (CRP)-antibody immobilization methods were used: The first me...In this work, we describe an approach of detecting biomarkers by Surface Plasmon Resonance imaging (SPRi) technique in real samples. Two C-Reactive Protein (CRP)-antibody immobilization methods were used: The first method was based on direct physisorption of CRP-antibody onto gold surface;the second one was based on oriented CRP-antibody with protein G intermediate layer. The two developed immunosensors were tested against CRP antigen in phosphate buffer saline solution with the SPRi technique. The response of the developed immunosensors was reproducible and stable. The detection limit of 10 pg·mLǃ and 50 pg·mLǃ CRP-antigen was observed with and without protein G respectively with this technique. Moreover, the developed SPRi immunosensor was used for CRP-antigen detection in human plasma. A detection limit of 5 ng·mLǃ and 10 ng·mLǃ was obtained with and without protein G respectively. These obtained results were compared to those obtained with QCM (Quartz Crystal Microbalance) and Enzyme-Linked Immunosorbent Assay (ELISA) techniques.展开更多
Localized surface plasmon resonance(LSPR)can be supported by metallic nanoparticles and engineered nanostructures.An understanding of the spatially resolved near-field properties and dynamics of LSPR is important,but ...Localized surface plasmon resonance(LSPR)can be supported by metallic nanoparticles and engineered nanostructures.An understanding of the spatially resolved near-field properties and dynamics of LSPR is important,but remains experimentally challenging.We report experimental studies toward this aim using photoemission electron microscopy(PEEM)with high spatial resolution of sub-10 nm.Various engineered gold nanostructure arrays(such as rods,nanodisk-like particles and dimers)are investigated via PEEM using near-infrared(NIR)femtosecond laser pulses as the excitation source.When the LSPR wavelengths overlap the spectrum of the femtosecond pulses,the LSPR is efficiently excited and promotes multiphoton photoemission,which is correlated with the local intensity of the metallic nanoparticles in the near field.Thus,the local field distribution of the LSPR on different Au nanostructures can be directly explored and discussed using the PEEM images.In addition,the dynamics of the LSPR is studied by combining interferometric time-resolved pump-probe technique and PEEM.Detailed information on the oscillation and dephasing of the LSPR field can be obtained.The results identify PEEM as a powerful tool for accessing the near-field mapping and dynamic properties of plasmonic nanostructures.展开更多
A laboratory-made tumor cell detection device was fabricated based on both surface plasmon resonance imaging（SPRi） and image processing.In this device,a gravity-induced flow injection chip（gFIC） was exploited to r...A laboratory-made tumor cell detection device was fabricated based on both surface plasmon resonance imaging（SPRi） and image processing.In this device,a gravity-induced flow injection chip（gFIC） was exploited to replace a pump.Also two charge coupled devices（CCDs） were used to detect HepG2 cells by SPRi and image processing,respectively.The results of two CCDs are associated.Protein A was used to modify the sensing surface.The inlet angle was carefully adjusted for the device to get an enhanced image.In the test,the contrast among cell solutions at different concentrations can be easily distinguished.The other CCD using image processing can tell false-positive in some degree.This detection is label-free,real time,and precise.展开更多
A homemade array surface plasmon resonance （SPR）-based imaging biosensor was used to develop sensitive and fast immunoassays to determine sulfamethoxazole （SMOZ） and sulfamethazine （SMT） in buffer. Two conjugati...A homemade array surface plasmon resonance （SPR）-based imaging biosensor was used to develop sensitive and fast immunoassays to determine sulfamethoxazole （SMOZ） and sulfamethazine （SMT） in buffer. Two conjugations of sulfonamide-bovine serum albumin （BSA） were separately immobilized on two different rows of the array chip with one row as reference. The immobilization was carried out in the instrument to monitor the quantity of the conjugations immobilized. The antibody mixed with the sulfonamide in the buffer was injected over the surface of the chip to get a relative response which was inversely proportional to the concentration of the sulfonamide in the PBS buffer. Two calibration curves were constructed and the limit of detection for sufamethoxazole in buffer was 3.5 ng/mL and for sulfamethazine 0.6 ng/mL. The stability and specificity of the antibody were also studied. The monoclonal antibody did not bind with BSA.展开更多
We studied the near-field properties of localized surface plasmon resonances in finite linear gold nanochains using photoemission electron microscopy(PEEM).The localization of the electromagnetic field in the near-fie...We studied the near-field properties of localized surface plasmon resonances in finite linear gold nanochains using photoemission electron microscopy(PEEM).The localization of the electromagnetic field in the near-field region was mapped at high spatial resolution.By tuning the excitation laser wavelength,we can obtain the near-field spectra,from which the energy splitting between longitudinal(L)and transverse(T)plasmon modes can be revealed.In particular,the L-mode red shifts and the T-mode blue shifts with increasing chain length.The red shift of the L-mode is highly dependent on the gap distance.In contrast,the T-mode almost remains constant within the range of gap distance we investigated.This energy splitting between the L-mode and the T-mode of metallic chains is in agreement with previous far-field measurements,where it was explained by dipole-dipole near-field coupling.Here,we provide direct proof of this near-field plasmon coupling in nanochains via the above-described near-field measurements using PEEM.In addition,we explore the energy transport along the gold nanochains under excitation at oblique illumination via PEEM measurements together with numerical simulations.展开更多
Gold nanoparticles(AuNPs) interact with light and have strong and tunable surface plasmon resonance,which can be detected using multiple imaging modalities.These provide an unique opportunity for their potential appli...Gold nanoparticles(AuNPs) interact with light and have strong and tunable surface plasmon resonance,which can be detected using multiple imaging modalities.These provide an unique opportunity for their potential applications in optical imaging for early detection of cancer.In this review,we summarized nanoparticles targeting properties for cancer,plasmon optical properties of AuNPs,application of AuNPs for cancer optical imaging.Also discussed is the safety of AuNPs.展开更多
There is an increasing demand for advanced optical imaging techniques that can detect and resolve nanosize objects at a spatial resolution below the optical diffraction limit, especially in three-dimensional （3D） ce...There is an increasing demand for advanced optical imaging techniques that can detect and resolve nanosize objects at a spatial resolution below the optical diffraction limit, especially in three-dimensional （3D） cellular environments. In this study, using a polarization-activated localization scheme based on the orientation-dependent properties of anisotropic plasmonic metal nanoparticles （MNPs）, ＂photoswitchable＂ imaging of single gold nanorods （AuNRs） was accomplished not only in two dimensions but also in three dimensions. Moreover, the Rayleigh scattering background arising from the congested subcellular structures was efficiently suppressed. Thus, we obtained the 3D distributions of both the position and the orientation of the AuNRs inside the cells and investigated their intemalization kinetics. To our knowledge, this is the first demonstration of the confocal-like 3D imaging of non-fluorescence nanoparticles with a high resolution and almost zero background. This technique is easy to implement and should greatly facilitate MNP studies and applications in biomedicine and biology.展开更多
基金supported by the Instrument Developing Project of the Chinese Academy of Sciences (Grant No.YZ200740)the National Natural Science Foundation of China (Grant Nos.60978034 and 10974019)the National High Technology Research and Development Program of China (Grant No.2009AA03Z318)
文摘A laser scanning confocal imaging-surface plasmon resonance （LSCI-SPR） instrument integrated with a wavelength-dependent surface plasmon resonance （SPR） sensor and a laser scanning confocal microscopy （LSCM） is built to detect the bonding process of human IgG and fluorescent-labeled affinity purified antibodies in real time. The shifts of resonant wavelength at different reaction time stages are obtained by SPR, corresponding well with the changes of the fluorescence intensity collected by using LSCM. The instrument shows the merits of the combination and complementation of the SPR and LSCM, with such advantages as quantificational analysis, high spatial resolution and real time monitor, which are of great importance for practical applications in biosensor and life science.
文摘In this work, we describe an approach of detecting biomarkers by Surface Plasmon Resonance imaging (SPRi) technique in real samples. Two C-Reactive Protein (CRP)-antibody immobilization methods were used: The first method was based on direct physisorption of CRP-antibody onto gold surface;the second one was based on oriented CRP-antibody with protein G intermediate layer. The two developed immunosensors were tested against CRP antigen in phosphate buffer saline solution with the SPRi technique. The response of the developed immunosensors was reproducible and stable. The detection limit of 10 pg·mLǃ and 50 pg·mLǃ CRP-antigen was observed with and without protein G respectively with this technique. Moreover, the developed SPRi immunosensor was used for CRP-antigen detection in human plasma. A detection limit of 5 ng·mLǃ and 10 ng·mLǃ was obtained with and without protein G respectively. These obtained results were compared to those obtained with QCM (Quartz Crystal Microbalance) and Enzyme-Linked Immunosorbent Assay (ELISA) techniques.
基金This study was supported by funding from the Ministry of Education,Culture,Sports,Science,and Technology of Japan:KAKENHI Grant-in-Aid for Scientific Research No.23225006,Nanotechnology Platform(Hokkaido University)and the Low-Carbon Research Network of Japan.
文摘Localized surface plasmon resonance(LSPR)can be supported by metallic nanoparticles and engineered nanostructures.An understanding of the spatially resolved near-field properties and dynamics of LSPR is important,but remains experimentally challenging.We report experimental studies toward this aim using photoemission electron microscopy(PEEM)with high spatial resolution of sub-10 nm.Various engineered gold nanostructure arrays(such as rods,nanodisk-like particles and dimers)are investigated via PEEM using near-infrared(NIR)femtosecond laser pulses as the excitation source.When the LSPR wavelengths overlap the spectrum of the femtosecond pulses,the LSPR is efficiently excited and promotes multiphoton photoemission,which is correlated with the local intensity of the metallic nanoparticles in the near field.Thus,the local field distribution of the LSPR on different Au nanostructures can be directly explored and discussed using the PEEM images.In addition,the dynamics of the LSPR is studied by combining interferometric time-resolved pump-probe technique and PEEM.Detailed information on the oscillation and dephasing of the LSPR field can be obtained.The results identify PEEM as a powerful tool for accessing the near-field mapping and dynamic properties of plasmonic nanostructures.
基金Supported by the National Natural Science Foundation of China（Nos.31070772,31270907,21275129）.
文摘A laboratory-made tumor cell detection device was fabricated based on both surface plasmon resonance imaging（SPRi） and image processing.In this device,a gravity-induced flow injection chip（gFIC） was exploited to replace a pump.Also two charge coupled devices（CCDs） were used to detect HepG2 cells by SPRi and image processing,respectively.The results of two CCDs are associated.Protein A was used to modify the sensing surface.The inlet angle was carefully adjusted for the device to get an enhanced image.In the test,the contrast among cell solutions at different concentrations can be easily distinguished.The other CCD using image processing can tell false-positive in some degree.This detection is label-free,real time,and precise.
基金The authors greatly acknowledge the financial support from the National Natural Science Foundation of China(No.60027001 and 60302003)the National High Technology Research and Development program of China(No.20060100Z3044).
文摘A homemade array surface plasmon resonance （SPR）-based imaging biosensor was used to develop sensitive and fast immunoassays to determine sulfamethoxazole （SMOZ） and sulfamethazine （SMT） in buffer. Two conjugations of sulfonamide-bovine serum albumin （BSA） were separately immobilized on two different rows of the array chip with one row as reference. The immobilization was carried out in the instrument to monitor the quantity of the conjugations immobilized. The antibody mixed with the sulfonamide in the buffer was injected over the surface of the chip to get a relative response which was inversely proportional to the concentration of the sulfonamide in the PBS buffer. Two calibration curves were constructed and the limit of detection for sufamethoxazole in buffer was 3.5 ng/mL and for sulfamethazine 0.6 ng/mL. The stability and specificity of the antibody were also studied. The monoclonal antibody did not bind with BSA.
基金Grants-in-Aid for Scientific Research(Grant Nos.JP18H05205,JP17H01041,JP17H05245,and JP17H05459)We acknowledge the support from the Nanotechnology Platform(Hokkaido University)and Dynamic Alliance for Open Innovation Bridging Human,Environment and Materials(Five-Star Alliance)of MEXT.QSun also acknowledges the support from the National Natural Science Foundation of China(NSFC)(No.11527901).
文摘We studied the near-field properties of localized surface plasmon resonances in finite linear gold nanochains using photoemission electron microscopy(PEEM).The localization of the electromagnetic field in the near-field region was mapped at high spatial resolution.By tuning the excitation laser wavelength,we can obtain the near-field spectra,from which the energy splitting between longitudinal(L)and transverse(T)plasmon modes can be revealed.In particular,the L-mode red shifts and the T-mode blue shifts with increasing chain length.The red shift of the L-mode is highly dependent on the gap distance.In contrast,the T-mode almost remains constant within the range of gap distance we investigated.This energy splitting between the L-mode and the T-mode of metallic chains is in agreement with previous far-field measurements,where it was explained by dipole-dipole near-field coupling.Here,we provide direct proof of this near-field plasmon coupling in nanochains via the above-described near-field measurements using PEEM.In addition,we explore the energy transport along the gold nanochains under excitation at oblique illumination via PEEM measurements together with numerical simulations.
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Gold nanoparticles(AuNPs) interact with light and have strong and tunable surface plasmon resonance,which can be detected using multiple imaging modalities.These provide an unique opportunity for their potential applications in optical imaging for early detection of cancer.In this review,we summarized nanoparticles targeting properties for cancer,plasmon optical properties of AuNPs,application of AuNPs for cancer optical imaging.Also discussed is the safety of AuNPs.
基金Acknowledgements This work was supported by the National Natural Sdence Foundation of China （Nos. 91027037, 21127009, 21425519 and 21221003）, Hunan University 985 fund, Tsinghua University Startup fund, the Natural Science Foundation of Zhejiang Province （No. LY16B050006） and Wenzhou Medical University Setup fund （No. QTJ15022）.
文摘There is an increasing demand for advanced optical imaging techniques that can detect and resolve nanosize objects at a spatial resolution below the optical diffraction limit, especially in three-dimensional （3D） cellular environments. In this study, using a polarization-activated localization scheme based on the orientation-dependent properties of anisotropic plasmonic metal nanoparticles （MNPs）, ＂photoswitchable＂ imaging of single gold nanorods （AuNRs） was accomplished not only in two dimensions but also in three dimensions. Moreover, the Rayleigh scattering background arising from the congested subcellular structures was efficiently suppressed. Thus, we obtained the 3D distributions of both the position and the orientation of the AuNRs inside the cells and investigated their intemalization kinetics. To our knowledge, this is the first demonstration of the confocal-like 3D imaging of non-fluorescence nanoparticles with a high resolution and almost zero background. This technique is easy to implement and should greatly facilitate MNP studies and applications in biomedicine and biology.
