An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization,...An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the con- denser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of bi- ological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.展开更多
Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has bee...Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has been termed as hormone refractory. To identify the proteins that mediate progression to the hormone-refractory state, we used protein-chip technology for mass profiling of patients＇ sera. This study included 16 patients with metastatic hormone-refractory prostate cancer who were initially treated with androgen deprivation therapy. Serum samples were collected from each patient at five time points： point A, pre-treatment; point B, at the nadir of the prostate- specific antigen （PSA） level; point C, PSA failure; point D, the early hormone-refractory phase; and point E, the late hormone-refractory phase. Using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, we performed protein mass profiling of the patients＇ sera and identified a 6 640-Da peak that increased with disease progression. Target proteins were partially purified, and by amino acid sequencing the peak was identified as a fragment of apolipoprotein C-I （ApoC-I）. Serum ApoC-I protein levels increased with disease progression. On immunohistochemical analysis, the ApoC-i protein was found localized to the cytoplasm of the hormone-refractory cancer cells. In this study, we showed an increase in serum ApoC-I protein levels in prostate cancer patients during their progression to the hormone-refractory state, which suggests that ApoC-I protein is related to progression of prostate cancer. However, as the exact role of ApoC-I in prostate cancer pathogenesis is unclear, further research is required.展开更多
Mass spectrometry imaging (MSI) technology can simultaneously obtain the spatial distribution of thousands of chemical compounds and has unique advantages compared to other techniques that allow mapping the surface of...Mass spectrometry imaging (MSI) technology can simultaneously obtain the spatial distribution of thousands of chemical compounds and has unique advantages compared to other techniques that allow mapping the surface of bio-tissue. Here, we combined an air flow-assisted desorption electrospray ionization (AFADESI) MSI device with a high-resolution mass spectrometer to optimize the system parameters and achieve more accurate spatial distribution characteristics for compounds of interest while investigating bio-tissue sections. The platform set-up, required instrumentation, sample pretreatment, parameter optimization and bio-tissue characterization are described and discussed.Finally, the parameter conditions that can provide optimal ionic intensity and enhanced resolution were confirmed. The reasonable resolution and sensitivity improvements of AFADESI-MSI have been achieved through tandem a high-resolution mass spectrometer system, therefore, it would be a promising technique for the bio-tissue imaging analysis.展开更多
A simple method was developed for rapid and direct profiling of alkaloids in medical herbs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）. The dry herbs were first gro...A simple method was developed for rapid and direct profiling of alkaloids in medical herbs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）. The dry herbs were first ground to powder and passed through a stainless steel sieve, mixed with the matrix solution to form a homogeneous suspension, which was then directly applied to MALDI analysis. Several matrices were investigated and 2,5- dihydroxybenzoic acid（DHB） was chosen as the optimized one, and the particle with small size was found to favor the analysis. Using this method, the profiles of alkaloids in several medical herbs were readily obtained, and the toxicities of crude and processed Radix Aconiti Lateralis Preparata were compared via the relative intensities of the peaks of the corresponding toxic components shown in their MALDI spectra. This method therefore provides a rapid and reliable protocol for obtaining profiles of alkaloids in medical herbs by using MALDI-TOF MS.展开更多
A novel atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry(AP-MALDIMS)method was established for the facile detection of pesticides in ambient environment.Four kinds of multi-walled car...A novel atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry(AP-MALDIMS)method was established for the facile detection of pesticides in ambient environment.Four kinds of multi-walled carbon nanotubes(MWCNTs)-based matrix were synthesized and utilized to enhance the ionization efficiency of pesticides.Organophosphorus,anilinopyrimidine,carbamate,triazine,triazole and benzimidazole pesticides were directly desorbed and ionized from MWCNTs-based matrix in ambient environment,showing clear background and good sensitivity.In a comparison,Fe3O4-doped MWCNTs improved the intensity of pesticide ions more than the other three matrices.Moreover,MWCNTs-based matrix exhibited better performance than organic matrix.Quantitative analysis of pesticides using APMALDI-MS was validated to be adequate linearity,repeatability and sensitivity.Overall,AP-MALDI-MS combined with MWCNTs-based matrix enables the directly qualitative and quantitative analysis of pesticides in ambient environment.展开更多
Ionization efficiency is an important factor for ion sources in mass spectrometry and ion mobility spectrometry.Using helium as the discharge gas,acetone as the sample,and high-field asymmetric ion mobility spectrome...Ionization efficiency is an important factor for ion sources in mass spectrometry and ion mobility spectrometry.Using helium as the discharge gas,acetone as the sample,and high-field asymmetric ion mobility spectrometry（FAIMS） as the ion detection method,this work investigates in detail the effects of discharge parameters on the efficiency of ambient metastableinduced desorption ionization（AMDI） at atmospheric pressure.The results indicate that the discharge power and gas flow rate are both significantly correlated with the ionization efficiency.Specifically,an increase in the applied discharge power leads to a rapid increase in the ionization efficiency,which gradually reaches equilibrium due to ion saturation.Moreover,when the discharge voltage is fixed at 2.1 kV,a maximum efficiency can be achieved at the flow rate of 9.0 m/s.This study provides a foundation for the design and application of AMDI for on-line detection with mass spectrometry and ion mobility spectrometry.展开更多
Background and Objective: Early diagnosis of nasopharyngeal carcinoma (NPC) is difficult due to the insufficient specificity of the conventional examination method. This study was to investigate potential and consiste...Background and Objective: Early diagnosis of nasopharyngeal carcinoma (NPC) is difficult due to the insufficient specificity of the conventional examination method. This study was to investigate potential and consistent biomarkers for NPC, particularly for early detection of NPC. Methods: A proteomic pattern was identified in a training set (134 NPC patients and 73 control individuals) using the surface-enhanced laser desorption and ionization-mass spectrometry (SELDI-MS), and used to screen the test set (44 NPC patients and 25 control individuals) to determine the screening accuracy. To confirm the accuracy, it was used to test another group of 52 NPC patients and 32 healthy individuals at 6 months later. Results: Eight proteomic biomarkers with top-scored peak mass/charge ratios (m/z) of 8605 Da, 5320 Da, 5355 Da, 5380 Da, 5336 Da, 2791 Da, 7154 Da, and 9366 Da were selected as the potential biomarkers of NPC with a sensitivity of 90.9% (40/44) and a specificity of 92.0% (23/25). The performance was better than the current diagnostic method by using the Epstein-Barr virus (EBV) capsid antigen IgA antibodies (VCA/IgA). Similar sensitivity (88.5%) and specificity (90.6%) were achieved in another group of 84 samples. Conclusion: SELDI-MS profiling might be a potential tool to identify patients with NPC, particularly at early clinical stages.展开更多
Gene expression profile changes in brain regions following traumatic brain injury at the gene level cannot sufficiently elucidate gene expression time, expression amount, protein post-translational processing or modif...Gene expression profile changes in brain regions following traumatic brain injury at the gene level cannot sufficiently elucidate gene expression time, expression amount, protein post-translational processing or modification. Therefore, it is necessary to quantitatively analyze the gene expression profile using proteomic techniques. In the present study, we established a rat model of closed brain injury using Marmarou＇s weight-drop device, and investigated hippocampal differential protein expression using two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry. A total of 364 protein peaks were detected on weak cation exchange-2 protein chips, including 37 differential protein peaks. 345 protein peaks were detected on immobilized metal affinity capture arrays-Cu, including 12 differential protein peaks Further examination of these differential proteins revealed that glucose-regulated protein and proteasome subunit alpha type 3 expression were significantly upregulated post-injury. These results indicate that brain injury can alter protein expression in the hippocampus, and that glucose-regulated protein and proteasome subunit alpha type 3 are closely associated with the occurrence and development of traumatic brain injury.展开更多
A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported. Compared to the conventional dried-droplet method, the efficiency of ionization and sign...A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported. Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved. The mechanism was also analyzed.展开更多
Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how...Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how to compare unknown strains to the known one quickly, semi-automatically and accurately. In this paper, we present a software tool that allows flexibly microbial matching in a user-friendly way, by letting the users to customize comparison parameters including: in vitro transcription enzyme, mass tolerance,minimum fragment length, intensity threshold and corresponding weights. We provide three spectral scoring functions to compute the affin-ity between the species. Therefore, the precision of microbial comparison increases. To test and verify this tool, we employed experimental spectral data based on MALDI-TOFMS and the gene sequences of E.coli and Salmonella. This software is written in Java for cross-platform intention.展开更多
Surface-assisted laser desorption/ionization mass spectrometry(SALDI-MS)uses inorganic nanomaterials as matrixes to facilitate desorption and ionization of analytes.Compared with the traditional matrix-assisted laser ...Surface-assisted laser desorption/ionization mass spectrometry(SALDI-MS)uses inorganic nanomaterials as matrixes to facilitate desorption and ionization of analytes.Compared with the traditional matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)technique,SALDI-MS has the advantages of less interference in the low mass range,better reproducibility and higher salt tolerance.It is highly suitable for the analysis of small molecule compounds.In recent years,researchers have developed a range of nanomaterials that are successfully applied to the field of small molecule drug and metabolite analysis including drug screening and quantification,drug delivery,metabolite profiling,biomarker discovery and so forth.This review summarizes the latest progress of SALDI-MS matrix materials such as metal-based,carbon-based,silica-based nanomaterials and organic framework nanomaterials and their applications.In addition,our perspective of SALDI-MS technology is also discussed for further advancement.展开更多
Native and methyl-esterified sialylated glycans were analyzed with 2,4,6-trihydroxyacetophenone（THAP）and 2,5-dihydroxybenzoic acid（DHB）as matrix by a matrix-assisted laser desorption/ionization time-of-flight mass...Native and methyl-esterified sialylated glycans were analyzed with 2,4,6-trihydroxyacetophenone（THAP）and 2,5-dihydroxybenzoic acid（DHB）as matrix by a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer（MALDI-TOF MS）.High quality negative-ion spectra of commercial sialylated glycan were obtained with THAP as matrix.Detection limit of the glycan was less than 0.1 pmol.After methyl esterification of sialic acid（SA）residue,sialylated glycans were detected sensitively in the positive-ion mode using DHB as matrix.Neutral and sialylated glycans from the mixture of asialofetuin and fetuin were methylesterified and simultaneously recognized in one manipulation.Methyl esterification of SA residue offers a convenient and sensitive way to identify the structure of N-linked glycans for glycan profiling.展开更多
Cancer cell spheroids(CCS) are a valuable three-dimensional cell model in cancer studies because they could replicate numerous characteristics of solid tumors. Increasing researches have used matrix-assisted laser des...Cancer cell spheroids(CCS) are a valuable three-dimensional cell model in cancer studies because they could replicate numerous characteristics of solid tumors. Increasing researches have used matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) to investigate the spatial distribution of endogenous compounds(e.g., lipids) in CCS. However, only limited lipid species can be detected owing to a low ion yield by using MALDI. Besides, it is still challenging to fully characterize the structural diversity of lipids due to the existence of isomeric/isobaric species. Here, we carried out the initial application of MALDI coupled with laser-postionization(MALDI-2) and trapped ion mobility spectrometry(TIMS) imaging in HCT116 colon CCS to address these challenges. We demonstrated that MALDI-2 is capable of detecting more number and classes of lipids in HCT116 colon CCS with higher signal intensities than MALDI. TIMS could successfully separate numerous isobaric/isomeric species of lipids in CCS. Interestingly, we found that some isomeric/isobaric species have totally different spatial distributions in colon CCS. Further MS/MS imaging analysis was employed to determine the compositions of fatty acid chains for isomeric species by examining disparities in signal intensities and spatial distributions of product ions. This work stresses the robust ability of TIMS and MALDI-2 imaging in analyzing endogenous lipids in CCS, which could potentially become powerful tools for future cancer studies.展开更多
文摘An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the con- denser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of bi- ological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.
文摘Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has been termed as hormone refractory. To identify the proteins that mediate progression to the hormone-refractory state, we used protein-chip technology for mass profiling of patients＇ sera. This study included 16 patients with metastatic hormone-refractory prostate cancer who were initially treated with androgen deprivation therapy. Serum samples were collected from each patient at five time points： point A, pre-treatment; point B, at the nadir of the prostate- specific antigen （PSA） level; point C, PSA failure; point D, the early hormone-refractory phase; and point E, the late hormone-refractory phase. Using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, we performed protein mass profiling of the patients＇ sera and identified a 6 640-Da peak that increased with disease progression. Target proteins were partially purified, and by amino acid sequencing the peak was identified as a fragment of apolipoprotein C-I （ApoC-I）. Serum ApoC-I protein levels increased with disease progression. On immunohistochemical analysis, the ApoC-i protein was found localized to the cytoplasm of the hormone-refractory cancer cells. In this study, we showed an increase in serum ApoC-I protein levels in prostate cancer patients during their progression to the hormone-refractory state, which suggests that ApoC-I protein is related to progression of prostate cancer. However, as the exact role of ApoC-I in prostate cancer pathogenesis is unclear, further research is required.
基金supported by the National Instrumentation Program (No. 2016YFF0100304)the National Natural Science Foundation of China(Nos. 21335007, 81773678)+1 种基金the CAMS Innovation Fund for Medical Sciences(No. 2016-12 M-1-009)PUMC Youth Fund and the Fundamental Research Funds for the Central Universities(No. 3332015177)
文摘Mass spectrometry imaging (MSI) technology can simultaneously obtain the spatial distribution of thousands of chemical compounds and has unique advantages compared to other techniques that allow mapping the surface of bio-tissue. Here, we combined an air flow-assisted desorption electrospray ionization (AFADESI) MSI device with a high-resolution mass spectrometer to optimize the system parameters and achieve more accurate spatial distribution characteristics for compounds of interest while investigating bio-tissue sections. The platform set-up, required instrumentation, sample pretreatment, parameter optimization and bio-tissue characterization are described and discussed.Finally, the parameter conditions that can provide optimal ionic intensity and enhanced resolution were confirmed. The reasonable resolution and sensitivity improvements of AFADESI-MSI have been achieved through tandem a high-resolution mass spectrometer system, therefore, it would be a promising technique for the bio-tissue imaging analysis.
基金Supported by the Major State Basic Research Development Program of China(No.2006CB5047060)the National Natural Science Foundation of China(Nos.30672600, 30772721)the Natural Science Foundation of Jilin Province, China (No.20060902)
文摘A simple method was developed for rapid and direct profiling of alkaloids in medical herbs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）. The dry herbs were first ground to powder and passed through a stainless steel sieve, mixed with the matrix solution to form a homogeneous suspension, which was then directly applied to MALDI analysis. Several matrices were investigated and 2,5- dihydroxybenzoic acid（DHB） was chosen as the optimized one, and the particle with small size was found to favor the analysis. Using this method, the profiles of alkaloids in several medical herbs were readily obtained, and the toxicities of crude and processed Radix Aconiti Lateralis Preparata were compared via the relative intensities of the peaks of the corresponding toxic components shown in their MALDI spectra. This method therefore provides a rapid and reliable protocol for obtaining profiles of alkaloids in medical herbs by using MALDI-TOF MS.
基金financially supported by the Science and Technology Development Plan Project of Jilin Province(Nos.20210204098YY,20200201093JC)。
文摘A novel atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry(AP-MALDIMS)method was established for the facile detection of pesticides in ambient environment.Four kinds of multi-walled carbon nanotubes(MWCNTs)-based matrix were synthesized and utilized to enhance the ionization efficiency of pesticides.Organophosphorus,anilinopyrimidine,carbamate,triazine,triazole and benzimidazole pesticides were directly desorbed and ionized from MWCNTs-based matrix in ambient environment,showing clear background and good sensitivity.In a comparison,Fe3O4-doped MWCNTs improved the intensity of pesticide ions more than the other three matrices.Moreover,MWCNTs-based matrix exhibited better performance than organic matrix.Quantitative analysis of pesticides using APMALDI-MS was validated to be adequate linearity,repeatability and sensitivity.Overall,AP-MALDI-MS combined with MWCNTs-based matrix enables the directly qualitative and quantitative analysis of pesticides in ambient environment.
基金supported by National Natural Science Foundation of China(No.61374016)the Changzhou Science and Technology Support Program,China(No.CE20120081)the External Cooperation Program of Chinese Academy of Sciences(No.GJHZ1218)
文摘Ionization efficiency is an important factor for ion sources in mass spectrometry and ion mobility spectrometry.Using helium as the discharge gas,acetone as the sample,and high-field asymmetric ion mobility spectrometry（FAIMS） as the ion detection method,this work investigates in detail the effects of discharge parameters on the efficiency of ambient metastableinduced desorption ionization（AMDI） at atmospheric pressure.The results indicate that the discharge power and gas flow rate are both significantly correlated with the ionization efficiency.Specifically,an increase in the applied discharge power leads to a rapid increase in the ionization efficiency,which gradually reaches equilibrium due to ion saturation.Moreover,when the discharge voltage is fixed at 2.1 kV,a maximum efficiency can be achieved at the flow rate of 9.0 m/s.This study provides a foundation for the design and application of AMDI for on-line detection with mass spectrometry and ion mobility spectrometry.
基金National Science & Technology Pillar Program in the Eleventh Five-year Plan of China (No. 2006BAI02A11)Planned Sci-Tech Project of Guangdong Province (No. 2005B50301006)
文摘Background and Objective: Early diagnosis of nasopharyngeal carcinoma (NPC) is difficult due to the insufficient specificity of the conventional examination method. This study was to investigate potential and consistent biomarkers for NPC, particularly for early detection of NPC. Methods: A proteomic pattern was identified in a training set (134 NPC patients and 73 control individuals) using the surface-enhanced laser desorption and ionization-mass spectrometry (SELDI-MS), and used to screen the test set (44 NPC patients and 25 control individuals) to determine the screening accuracy. To confirm the accuracy, it was used to test another group of 52 NPC patients and 32 healthy individuals at 6 months later. Results: Eight proteomic biomarkers with top-scored peak mass/charge ratios (m/z) of 8605 Da, 5320 Da, 5355 Da, 5380 Da, 5336 Da, 2791 Da, 7154 Da, and 9366 Da were selected as the potential biomarkers of NPC with a sensitivity of 90.9% (40/44) and a specificity of 92.0% (23/25). The performance was better than the current diagnostic method by using the Epstein-Barr virus (EBV) capsid antigen IgA antibodies (VCA/IgA). Similar sensitivity (88.5%) and specificity (90.6%) were achieved in another group of 84 samples. Conclusion: SELDI-MS profiling might be a potential tool to identify patients with NPC, particularly at early clinical stages.
基金the National Natural Science Foundation of China,No. 30471934
文摘Gene expression profile changes in brain regions following traumatic brain injury at the gene level cannot sufficiently elucidate gene expression time, expression amount, protein post-translational processing or modification. Therefore, it is necessary to quantitatively analyze the gene expression profile using proteomic techniques. In the present study, we established a rat model of closed brain injury using Marmarou＇s weight-drop device, and investigated hippocampal differential protein expression using two-dimensional gel electrophoresis and surface-enhanced laser desorption ionization-time of flight-mass spectrometry. A total of 364 protein peaks were detected on weak cation exchange-2 protein chips, including 37 differential protein peaks. 345 protein peaks were detected on immobilized metal affinity capture arrays-Cu, including 12 differential protein peaks Further examination of these differential proteins revealed that glucose-regulated protein and proteasome subunit alpha type 3 expression were significantly upregulated post-injury. These results indicate that brain injury can alter protein expression in the hippocampus, and that glucose-regulated protein and proteasome subunit alpha type 3 are closely associated with the occurrence and development of traumatic brain injury.
文摘A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported. Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved. The mechanism was also analyzed.
文摘Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how to compare unknown strains to the known one quickly, semi-automatically and accurately. In this paper, we present a software tool that allows flexibly microbial matching in a user-friendly way, by letting the users to customize comparison parameters including: in vitro transcription enzyme, mass tolerance,minimum fragment length, intensity threshold and corresponding weights. We provide three spectral scoring functions to compute the affin-ity between the species. Therefore, the precision of microbial comparison increases. To test and verify this tool, we employed experimental spectral data based on MALDI-TOFMS and the gene sequences of E.coli and Salmonella. This software is written in Java for cross-platform intention.
基金State Key Laboratory of Natural and Biomimetic Drugs(Peking University)the National Natural Science Foundation of China(Grant No.21804123)。
文摘Surface-assisted laser desorption/ionization mass spectrometry(SALDI-MS)uses inorganic nanomaterials as matrixes to facilitate desorption and ionization of analytes.Compared with the traditional matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)technique,SALDI-MS has the advantages of less interference in the low mass range,better reproducibility and higher salt tolerance.It is highly suitable for the analysis of small molecule compounds.In recent years,researchers have developed a range of nanomaterials that are successfully applied to the field of small molecule drug and metabolite analysis including drug screening and quantification,drug delivery,metabolite profiling,biomarker discovery and so forth.This review summarizes the latest progress of SALDI-MS matrix materials such as metal-based,carbon-based,silica-based nanomaterials and organic framework nanomaterials and their applications.In addition,our perspective of SALDI-MS technology is also discussed for further advancement.
基金Supported by the National Natural Science Foundation of China(30800193)Grant from Centre for International Mobility(CIMO),Finland
文摘Native and methyl-esterified sialylated glycans were analyzed with 2,4,6-trihydroxyacetophenone（THAP）and 2,5-dihydroxybenzoic acid（DHB）as matrix by a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer（MALDI-TOF MS）.High quality negative-ion spectra of commercial sialylated glycan were obtained with THAP as matrix.Detection limit of the glycan was less than 0.1 pmol.After methyl esterification of sialic acid（SA）residue,sialylated glycans were detected sensitively in the positive-ion mode using DHB as matrix.Neutral and sialylated glycans from the mixture of asialofetuin and fetuin were methylesterified and simultaneously recognized in one manipulation.Methyl esterification of SA residue offers a convenient and sensitive way to identify the structure of N-linked glycans for glycan profiling.
基金supported by the National Natural Science Foundation of China (Nos.22036001, 22276034 and 22106130)。
文摘Cancer cell spheroids(CCS) are a valuable three-dimensional cell model in cancer studies because they could replicate numerous characteristics of solid tumors. Increasing researches have used matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) to investigate the spatial distribution of endogenous compounds(e.g., lipids) in CCS. However, only limited lipid species can be detected owing to a low ion yield by using MALDI. Besides, it is still challenging to fully characterize the structural diversity of lipids due to the existence of isomeric/isobaric species. Here, we carried out the initial application of MALDI coupled with laser-postionization(MALDI-2) and trapped ion mobility spectrometry(TIMS) imaging in HCT116 colon CCS to address these challenges. We demonstrated that MALDI-2 is capable of detecting more number and classes of lipids in HCT116 colon CCS with higher signal intensities than MALDI. TIMS could successfully separate numerous isobaric/isomeric species of lipids in CCS. Interestingly, we found that some isomeric/isobaric species have totally different spatial distributions in colon CCS. Further MS/MS imaging analysis was employed to determine the compositions of fatty acid chains for isomeric species by examining disparities in signal intensities and spatial distributions of product ions. This work stresses the robust ability of TIMS and MALDI-2 imaging in analyzing endogenous lipids in CCS, which could potentially become powerful tools for future cancer studies.
