Synchrotron radiation-based Fourier-transform infrared spectromicroscopy for characterization of the protein/peptide distribution in single microspheres

The present study establishes a visualization method for the measurement of the distribution and localization of protein/peptide constituents within a single poly-lactide-co-glycolide(PLGA) microsphere using synchrotron radiation–based Fourier-transform infrared spectromicroscopy(SR-FTIR).The representative infrared wavenumbers specific for protein/peptide(Exenatide) and excipient(PLGA) were identified and chemical maps at the single microsphere level were generated by measuring and plotting the intensity of these specific bands.For quantitative analysis of the distribution within microspheres,Matlab software was used to transform the map file into a 3D matrix and the matrix values specific for the drug and excipient were extracted.Comparison of the normalized SR-FTIR maps of PLGA and Exenatide indicated that PLGA was uniformly distributed,while Exenatide was relatively non-uniformly distributed in the microspheres.In conclusion,SR-FTIR is a rapid,nondestructive and sensitive detection technology to provide the distribution of chemical constituents and functional groups in microparticles and microspheres.

An APXPS endstation for gas–solid and liquid–solid interface studies at SSRF

In the past few decades, various surface analysis techniques find wide applications in studies of interfacial phenomena ranging from fundamental surface science,catalysis, environmental science and energy materials.With the help of bright synchrotron sources, many of these techniques have been further advanced into novel in-situ/operando tools at synchrotron user facilities, providing molecular level understanding of chemical/electrochemical processes in-situ at gas–solid and liquid–solid interfaces.Designing a proper endstation for a dedicated beamline is one of the challenges in utilizing these techniques efficiently for a variety of user's requests. Many factors,including pressure differential, geometry and energy of the photon source, sample and analyzer, need to be optimized for the system of interest. In this paper, we discuss the design and performance of a new endstation at beamline02 B at the Shanghai Synchrotron Radiation Facility for ambient pressure X-ray photoelectron spectroscopy studies.This system, equipped with the newly developed hightransmission HiPP-3 analyzer, is demonstrated to be capable of efficiently collecting photoelectrons up to 1500 eV from ultrahigh vacuum to ambient pressure of 20 mbar.The spectromicroscopy mode of HiPP-3 analyzer also enables detection of photoelectron spatial distribution with resolution of 2.8 ± 0.3 lm in one dimension. In addition,the designing strategies of systems that allow investigations in phenomena at gas–solid interface and liquid–solid interface will be highlighted through our discussion.

Interfacial processes and mechanisms of synergistic degradation of dichlorobiphenyl by white rot fungi and magnetite nanoparticles

The rapid increase in the artificial syntheses of organic pollutants has raised widespread concern.However,the mechanisms by which fungi degrade these new organic pollutants in the environment and adapt to environmental stressors remain unclear.In this study,Phanerochaete chrysosporium,a model white rot fungus,was used to explore the interfacial processes and mechanisms for synergistic degradation of 4,4′-dichlorobiphenyl(PCB15)with magnetite nanoparticles.The results showed that after 3 and 5 days of cultivation with Phanerochaete chrysosporium alone,the rates for PCB15 degradation were 32%and 65%,respectively,indicating that the white rot fungus itself was able to degrade the organic pollutant.Moreover,the addition of magnetite nanoparticles significantly enhanced the degradation of PCB15 by Phanerochaete chrysosporium.After cocultivation for 3 and 5 days,the rates for PCB15 degradation increased to 42%and 84%,respectively.Synchrotron radiation-based Fourier transform infrared spectromicroscopy(SR-FTIR)showed that the magnetite particles were tightly adhered to the fungal hyphae and were unevenly distributed on the hyphal surfaces.Furthermore,cocultivation of the fungus and magnetite nanoparticles significantly enhanced the nanozymatic activity of magnetite.A linear regression model provided a significantly negative correlation(r=−0.96,p<0.001)between the nanozymatic activity of the magnetite and the concentration ratio of the PCB15,supporting the hypothesis that white rot fungi degraded the PCB15 by enhancing the nanozyme activity of magnetite.High-resolution X-ray photoelectron spectroscopy(XPS)revealed that the nanozymatic activity of magnetite was mainly governed by oxygen vacancies on the mineral surfaces rather than the iron valence.Together,these findings increase our understanding of the powerful capabilities of fungi in terms of stress resistance and adaptation to extreme environments and provide new insights into fungal-mediated degradation of organic pollutants for soil remediation in contaminated sites.

Applications of synchrotron-based X-ray techniques in environmental science

Synchrotron-based X-ray techniques have been widely applied to the fields of environmental science due to their element-specific and nondestructive properties and unique spectral and spatial resolution advantages.The techniques are capable of in situ investigating chemical speciation,microstructure and mapping of elements in question at the molecular or nanometer scale,and thus provide direct evidence for reaction mechanisms for various environmental processes.In this contribution,the applications of three types of the techniques commonly used in the fields of environmental research are reviewed,namely X-ray absorption spectroscopy (XAS),X-ray fluorescence (XRF) spectroscopy and scanning transmission X-ray microscopy (STXM).In particular,the recent advances of the techniques in China are elaborated,and a selection of the applied examples are provided in the field of environmental science.Finally,the perspectives of synchrotron-based X-ray techniques are discussed.With their great progress and wide application,the techniques have revolutionized our understanding of significant geo-and bio-chemical processes.It is anticipatable that synchrotron-based X-ray techniques will continue to play a significant role in the fields and significant advances will be obtained in decades ahead.