真空紫外激光解吸/电离单细胞质谱成像装置的研制和调试

开发同时具有亚微米分辨率以及高检测灵敏度的无基质质谱成像方法,对于可视化单细胞生物样品具有重要意义。在此,提出了真空紫外激光解吸/电离飞行时间质谱成像(VUVDI-ToFMSI)方法。通过调整基频光波长至777.7、403.22和255 nm,汞蒸气池中氩气气压至1100 Pa以及温度至240℃,获得接近13μJ/pulse的高强度VUV激光能量;同时,设计的同轴光路聚焦VUV激光至亚微米水平;另外,通过进一步调整偏转电场、离子聚焦电场以及反射电场的电负性以及电压等参数,离子的飞行路径得到矫正与优化。基于这种方法,实现了单个HeLa细胞中外源性药物亚甲基蓝(m/z 284.4)、内源性代谢物离子信号m/z 152.1以及m/z 81.1的纳米级成像(~500 nm/pixel),结果表明它们分别富集在细胞质、细胞核以及核仁内,证明了该方法在绘制单细胞不同区室内外源和内源性化学物质的高分辨以及高灵敏度的成像能力。该VUVDI-ToFMSI平台将为了解更多生物样本的精细结构与功能提供更完整、更深入的化学信息。

Aggregation-induced delayed electrochemiluminescence of organic dots in aqueous media

Full utilization of the excited species at both singlet states(1R*)and triplet states(3R*)is crucial to improving electrochemiluminescence(ECL)efficiency but is challenging for organic luminescent materials.Here,an aggregation-induced delayed ECL(AIDECL)active organic dot(OD)containing a benzophenone acceptor and dimethylacridine donor is reported,which shows high ECL efficiency via reverse intersystem crossing(RISC)of non-emissive 3R*to emissive 1R*,overcoming the spin-forbidden radiative decay from 3R*.By introducing dual donor-acceptor pairs into luminophores,it is found that nonradiative pathway could be further suppressed via enhanced intermolecular weak interactions,and multiple spin-up conversion channels could be activated.As a consequence,the obtained OD enjoys a 6.8-fold higher ECL efficiency relative to the control AIDECL-active OD.Single-crystal studies and theoretical calculations reveal that the enhanced AIDECL behaviors come from the acceleration of both radiative transition and RISC.This work represents a major step towards purely organic,high-efficiency ECL dyes and a direction for the design of next-generation ECL dyes at the molecular level.

Nature-inspired design of droplet-synthesized polymeric nanoelectrode for photoelectrochemical microRNA sensing within single cells

Nanoelectrodes have been shown to be powerful tools for nanoscopic research on single entities,deepening the understanding of heterogeneity and stochastics for single molecules,nanoparticles and cells[1–3].However,despite their importance,current nanoelectrode preparations are highly restrained to flame/electrochemical etching,metal sputtering,electrochemical deposition,etc.[3],resulting in a limited range of materials(mainly gold,platinum and carbon)for potential-resolved detection of redox-active species(Table S1 online).The enrichment of preparation methods to introduce novel materials and mechanisms should prove significant for the development of nanoelectrodes.

High-gain signal-on PEDOT:PSS organic photoelectrochemical transistor biosensing modulated by a MXene/MOFs/NiO Schottky heterojunction

Herein we report a high-gain signal-on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)organic electrochemical transistor(OECT)biosensing using an accumulation-mode PEDOT:PSS OECT modulated by a light-fueled MXene/MOFs/Ni O Schottky heterojunction.In such a system,the MXene/MOFs/Ni O Schottky heterojunction exhibited superior gating effect,as it not only enabled the fast-directional charge transfer but also guaranteed the maximal accessibility of the electrolyte to topped 2D MXene with large surface area.In linkage with a bi-enzyme cascade system,the quinone derivatives produced by the cascade reaction of alkaline phosphatase(ALP)and tyrosinase(TYR)could serve as effective electron acceptors for the representative Ti_(3)C_(2)/PCN-224/Ni O heterojunction,underpinning an innovative method for sensitive detection of ALP activity with a low detection limit of 0.001 U L^(-1).Remarkably,the as-developed system demonstrated a remarkable current gain as high as near 10^(4),which to our knowledge is the highest one among existing OECT biosensory devices.This work represents a generic protocol to develop the novel signal-on PEDOT:PSS OECT platform towards biochemical detection and beyond.

Emerging advances in plasmonic nanoassemblies for biosensing and cell imaging

Integrating discrete plasmonic nanoparticles into assemblies can induce plasmonic coupling that produces collective plasmonic properties,which are not available for single nanoparticles.Theoretical analysis revealed that plasmonic coupling derived from assemblies could produce stronger electromagnetic field enhancement effects.Thus,plasmonic assemblies enable better performance in plasmon-based applications,such as enhanced fluorescence and Raman effects.This makes them hold great potential for trace analyte detection and nanomedicine.Herein,we focus on the recent advances in various plasmonic nanoassembles such as dimers,tetramers,and core-satellite structures,and discuss their applications in biosensing and cell imaging.The fabrication strategies for self-assembled plasmonic nanostructures are described,including top-down strategies,self-assembly methods linked by DNA,ligand,polymer,amino acid,or proteins,and chemical overgrowth methods.Thereafter,their applications in biosensor and cell imaging based on dark-field imaging,surface-enhanced Raman scattering,plasmonic circular dichroism,and fluorescence imaging are discussed.Finally,the remaining challenges and prospects are elucidated.

Single-particle detection of cholesterol based on the host-guest recognition induced plasmon resonance energy transfer

Plasmon resonance energy transfer(PRET) occurs between the plasmonic nanoparticles(NPs) and organic dyes forming donor-acceptor pairs, which has great potential in quantitative analytical chemistry because of its excellent sensitivity under dark-field microscopy(DFM). Herein, we introduce supramolecular β-cyclodextrin(β-CD) to design a host-guest recognition plasmonic nano-structure modified gold nanoparticles(GNPs), while GNPs and rhodamine molecule(RB) act as the donor and acceptor, respectively. In the presence of the target cholesterol, due to the stronger binding of cholesterol with β-CD, RB molecules are released, inducing the inhibition of PRET, as well as the increase of the scattering intensity of GNPs.The proposed strategy achieves a linear range from 0.02 μmol/L to 2.0 μmol/L for cholesterol detection,and reaches a limit of detection(LOD) of 6.7 nmol/L. This host-guest recognition strategy can easily integrate receptor-donor pair into one nanoparticle, which simplifies the construction of the PRET platform,and further provides an effective approach for PRET-based analytical applications. Afterwards, the proposed PRET strategy was successfully applied for the detection of cholesterol in serum samples with high sensitivity and specificity. The proposed method provides an effective clinically potential means for the detection of cholesterol and other disease-related biomarkers.

Cell mechanics and energetic costs of collective cell migration under confined microchannels

Mechanical force between cells relates to many biological processes of cell development.The cellular collective migration comes from cell-cell cooperation,and studying the intercellular mechanical properties helps elucidate collective cell migration.Herein,we studied cell-cell junctions,intercellular tensile force and the related cellular energetic costs in confined microchannels.Using the intercellular force sensor,we found that cells adapt to different confinement environments by regulating intercellular force,and thereby the relationship between collective cell migration and cell-cell junction were verified.Through the observation of cell orientation,actomyosin contractility,energetic costs,and glucose uptake,we can make a reasonable explanation of cell-force driven migration in different confined environments.Under highly confined conditions,the intercellular force and energetic costs are greater,and the cell orientation is more orderly.The collective migration behavior in confined spaces is closely related to the intercellular force and energetic costs,which is helpful to understand the collective migration behaviors in various confined spaces.

核酸功能化金纳米探针在活细胞荧光成像方面的应用

荧光标记的核酸功能化金纳米探针结合了纳米材料与核酸技术的优势,具有增强的稳定性、良好的生物相容性、独特的光学性质及精确的可编程性,开辟了活细胞传感的新纪元.信号放大型的核酸功能化金纳米探针在原位检测含量较低但功能强大的RNA、蛋白质等生物标志物方面尤其表现出明显的优势.本文从活细胞成像分析的角度,重点介绍了荧光标记的核酸功能化金纳米探针的性质、设计原理及应用进展.

Trace Ir(Ⅲ)complex enhanced electrochemiluminescence of AIE-active Pdots in aqueous media

Trace Ir(Ⅲ)complex enhanced aggregation-induced electrochemiluminescence(AIECL)of poly-tetraphenylethene(p TPE)in aqueous media was investigated for the first time.The poly-TPE end-capped by Ir(Ⅲ)complex(Ir@p TPE)and its corresponding model polymer poly-TPE(Ph@pTPE)could be synthesized by Suzuki coupling polymerization reaction of 1,2-bis(4-bromophenyl)-1,2-diphenylethene(M-1)with 1,2-diphenyl-1,2-bis(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)ethene(M-2)and the continuous Suzuki coupling end-capped reaction of poly-TPE-pinacol boronate with(pq)2 Ir(pico)Br and bromobenzene,respectively.Subsequently,the corresponding Ir@p TPE Pdots and Ph@p TPE Pdots encapsulated with poly(styrene-co-maleicanhydride)(PSMA)could be obtained by nanoprecipitation method.Compared with Ph@p TPE Pdots,the Ir@p TPE Pdots with a trace amount of Ir(Ⅲ)complex(1.34‰of Ir(Ⅲ)content,wt)could exhibit 9.9-fold enhancement of the electrochemiluminescence(ECL)signal for visual emission.This work provided a novel strategy on designing highly efficient ECL materials based on trace Ir(Ⅲ)-end capping AIE-active polymer dots.

Visualizing nanopore blinkings in parallel:a high-throughput nanopore array potential for ultra-rapid DNA sequencing

Upon finishing the sequencing of the first complete human genome in 2004[1],the demand for fast DNA reading with less than$1,000 has been fueled by the ever-increasing awareness for personalized medicine and clinical diagnosis[2,3].Plenty of sequencing techniques,from the original Sanger sequencing method to novel sequencing-by-synthesis technologies(Roche,Solexa,SOLi D,etc.)[3],have been developed rapidly in past decades,which are sug-

Appraisal of treatment outcomes in integrative medicine using metabonomics:Taking non-alcoholic fatty liver disease with spleen deficiency syndrome as an example

Objective:Appraisal of treatment outcomes in integrative medicine is a challenge due to a gap between the concepts of Western medicine(WM)disease and traditional Chinese medicine(TCM)syndrome.This study presents an approach for the appraisal of integrative medicine that is based on targeted metabolomics.We use non-alcoholic fatty liver disease with spleen deficiency syndrome as a test case.Methods:A patient-reported outcome(PRO)scale was developed based on literature review,Delphi consensus survey,and reliability and validity test,to quantitatively evaluate spleen deficiency syndrome.Then,a metabonomic foundation for the treatment of non-alcoholic fatty liver disease with spleen deficiency syndrome was identified via a longitudinal interventional trial and targeted metabolomics.Finally,an integrated appraisal model was established by identifying metabolites that responded in the treatment of WM disease and TCM syndrome as positive outcomes and using other aspects of the metabonomic foundation as independent variables.Results:Ten symptoms and signs were included in the spleen deficiency PRO scale.The internal reliability,content validity,discriminative validity and structural validity of the scale were all qualified.Based on treatment responses to treatments for WM disease(homeostasis model assessment of insulin resistance)or TCM syndrome(spleen deficiency PRO scale score)from a previous randomized controlled trial,two cohorts comprised of 30 participants each were established for targeted metabolomics detection.Twenty-five metabolites were found to be involved in successful treatment outcomes to both WM and TCM,following quantitative comparison and multivariate analysis.Finally,the model of the integrated appraisal system was exploratively established using binary logistic regression;it included 9 core metabolites and had the prediction probability of 83.3%.Conclusion:This study presented a new and comprehensive research route for integrative appraisal of treatment outcomes for WM disease and TCM syndrome.Critical research techniques used in this research included the development of a TCM syndrome assessment tool,a longitudinal interventional trial with verified TCM treatment,identification of homogeneous metabolites,and statistical modeling.

Construction of Nanocarriers Based on Endogenous Cell Membrane and Their Application in Nanomedicine

Inspired by the adaptation of cells to the surrounding environment,the combination of cell membrane and nanomaterials has gradually become a new type of biomimetic nanocomposite.The construction of endogenous membrane biomimetic nanocarriers(EMBNs)not only retains the structure of membrane surface protein,but also has the properties of nanoparticles(NPs),also provides the ability of natural interaction between nanomaterials and organisms,thus overcoming the severe challenges faced by traditional nanodelivery systems in clinical application.In this paper,the construction methods of EMBNs are reviewed,focusing on a simple method to prepare membrane proteins.Secondly,EMBNs were classified according a variety of cell membranes.Finally,the unique advantages of EMBNs in nanomedicine are introduced,including improving biocompatibility,homologous targeting ability,prolonging blood circulation time and immune escape abilty.In nanomedicine,such as targeted delivery,phototherapy,immunotherapy and tumor imaging,multifaceted biological interfaces through membrane masking provide a new approach for the development of multifunctional NPs.

A Supersmall Single-Cell Nanosensor for Intracellular K^(+) Detection

Intracellular potassium ions(K^(+))play pivotal roles in many physiological processes.Several K^(+)sensors have been developed for probing cellular K^(+)fluctuations.Nevertheless,the existing solutions are incompatible and impractical for intracellular K^(+)probing.Herein,we report a supersmall biomimetic K^(+)nanosensor to serve as a transmembrane vector capable of electrochemically detecting intracellular K^(+)in a minimally invasive manner.

Chemical Measurement and Analysis: from Phenomenon to Essence

The review summaries our achievements in optical,electrochemical,as well as mass spectrometry analysis and imaging with high sensitivity,specificity,and spatiotemporal resolution.We promoted the plasmonic imaging system,and developed ultra-sensitive plasmonic nanoprobes for the tracking of single molecules in single living cells,as well as plasmonic nanocatalysts for highly efficient energy conversion.In addition,we contributed a lot in electrogenerated chemiluminescence(ECL)analysis and imaging.Pioneering works including localized surface plasmon resonance(LSPR)enhanced ECL,ECL ratiometric detection,BPE based ECL system,multi-color ECL sensing as well as super-resolved ECL imaging have been initiated by our group.Furthermore,we also dedicated in nanopipette based electrochemical analysis in single living cells,as well as ESI-MS analysis on short time scale.

Visualized uranium rapid monitoring system based on self-enhanced electrochemiluminescence-imaging of amidoxime functionalized polymer nanoparticles

The development of uranyl ion detection technology has exhibited its significance in public security and environmental fields for the radioactivity and chemical toxicity of uranyl ion.The WHO standard of uranyl ion makes it necessary to develop highly sensitive uranyl rapid warning system in drinking water monitoring.Herein,a visualized rapid warning system for trace uranyl ion is carried out based on electrochemiluminescence(ECL) imaging technology to give an ultra-low limit of detection(LOD) and high selectivity.Amidoxime,a bi-functional group with both uranyl ion capturing and co-reactive functions,is modified on a conjugated polymer backbone with strong ECL signal to be prepared into three-in-one polymer nanoparticles(PNPs) with self-enhanced ECL property.The captured uranyl ion can enhance the ECL signal of PNPs via resonance energy transfer process to give the LOD as 0.5 ng/L,which is much lower than the known luminescent uranyl sensors.Furthermore,ECL imaging technology is introduced into realizing visualized uranyl rapid warning,and can be successfully applied on natural water samples.This study provides a novel strategy for uranyl rapid warning,and shows its potential meaning in public security and environmental fields.

Photo-stability and Photo-damage of SPASER Nanoparticles under Nanosecond Pulsed-laser

Comprehensive Summary SPASER nanoparticle(NP),with small size,ultranarrow spectral-line and good biocompatibility,is a potential biomedical nanoprobe.However,owning to the striking light absorption capacity of Au-resonator,huge energy could accumulate under strong pumping-laser,which would lead to poor photo-stability and unexpected photo-damage to SPASER NP,and is harmful to its future practical application but hasn't been systematically studied in experiment.

Highly Efficient Near-Infrared Ⅱ Electrochemiluminescence from NaYbF_(4) Core Mesoporous Silica Shell Nanoparticles

Due to less interference in biological imaging,nanomaterials with second near-infrared(NIR-II)window(950–1700 nm)emission have received tremendous attention.However,no reports on NIR-Ⅱ electrochemiluminescence(ECL)imaging exist because of the lack of high-efficiency NIR-Ⅱ ECL luminophores.Herein,we designed and synthesized a NaYbF4@SiO_(2) core–shell nanoparticle for the first time.

Smart Engineering of a Self-Powered and Integrated Nanocomposite for Intracellular MicroRNA Imaging

Over the past 2 years,many DNA motors have been synthesized and run in living cells,but there are still challenges in designing integrated DNA motors self-powered to enable autonomous intracellular walking without auxiliary additives.Herein,we report a smart strategy based on a DNA motor–MnO2 nanocomposite,which successfully meets these requirements of intracellular analysis and enables sensitive imaging of specific microRNAs(miRNAs)in living cells.

Human microbiome brings new insights to traditional Chinese medicine

The human microbiome has become a new frontier of life sciences and plays a crucial role in determining individual and population health.Over thousands of years of medical practice,practitioners of traditional Chinese medicine(TCM)developed an understanding of the importance and activity of commensal microorganisms without access to modern technology.In this review,we examine the theoretical similarities between modern studies of the human microbiome and TCM,and propose feasible strategies to integrate the 2 fields.Advances in our understanding of the human microbiome will also help to modernize the practice of TCM,thereby providing a basis for bridging the gap between modern medicine and TCM.