Nanoparticles (NPs) are useful as matrixes for the analyses of several types of biomolecules (including aminothiols, peptides, and proteins) and for mass spectrometric imaging through surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS), mainly because of their large surface area, strong absorption in the ultraviolet-near-infrared region, and ready functionalization. Metallic NPs, metal oxide NPs, and semiconductor quantum dots, unmodified or functionalized with recognition ligands, have a strong affinity toward analytes; therefore, they allow the enrichment of biomolecules, leading to improved sensitivity with minimal matrix interference in their mass spectra. SALDI-MS using NPs overcomes the two major problems commonly encountered in matrix-assisted laser desorption/ionization mass spectrometry: the presence of "sweet spots" and the high background signals in the low-mass region. In this tutorial review, we discuss the roles played by the nature, size, and concentration of the NPs, the buffer composition, and the laser energy in determining the sensitivity and mass ranges for the analytes. We describe internal standard SALDI-MS methods that allow the concentrations of analytes to be determined with low variation (relative standard deviations: <10%) and we highlight how the simplicity, sensitivity, and reproducibility of SALDI-MS approaches using various NPs allow the analyses of proteins and small analytes and the imaging of cells. 相似文献
Multifunctional ZrO2 nanoparticles (NPs) and ZrO2-SiO2 nanorods (NRs) have been successfully applied as the matrices for cyclodextrins and as affinity probes for enrichment of
peptides (leucine-enkephalin, methionine-enkephalin and thiopeptide), phosphopeptides (from tryptic digestion products of
β-casein) and phosphoproteins from complex samples (urine and milk) in atmospheric pressure matrix-assisted laser desorption/ionization
(MALDI) mass spectrometry (MS) and MALDI time-of-flight (TOF) MS. The results show that the ZrO2 NPs and ZrO2-SiO2 NRs can interact with target molecules (cyclodextrins, peptides, and proteins), and the signal intensities of the analytes
were significantly improved in MALDI-MS. The maximum signal intensities of the peptides were obtained at pH 4.5 using ZrO2 NPs and ZrO2-SiO2 NRs as affinity probes. The limits of detection of the peptides were found to be 75-105 fmol for atmospheric pressure MALDI-MS
and those of the cyclodextrins and β-casein were found to be 7.5-20 and 115-125 fmol, respectively, for MALDI-TOF-MS. In addition,
these nanomaterials can be applied as the matrices for the analysis of cyclodextrins in urine samples by MALDI-TOF-MS. ZrO2 NPs and ZrO2-SiO2 NRs efficiently served as electrostatic probes for peptide mixtures and milk proteins because 2–11 times signal enhancement
can be achieved compared with use of conventional organic matrices. Moreover, we have successfully demonstrated that the ZrO2 NPs can be effectively applied for enrichment of phosphopeptides from tryptic digestion of β-casein. Comparing ZrO2 NPs with ZrO2-SiO2 NRs, we found that ZrO2 NPs exhibited better affinity towards phosphopeptides than ZrO2-SiO2 NRs. Furthermore, the ZrO2 and ZrO2-SiO2 nanomaterials could be used to concentrate trace amounts of peptides/proteins from aqueous solutions without tedious washing
procedures. This approach is a simple, straightforward, separation-and washing-free approach for MALDI-MS analysis of cyclodextrins,
peptides, proteins, and tryptic digestion products of phosphoproteins.
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Nanoparticle assisted laser desorption/ionization mass spectrometry (NPs-ALDI-MS) shows remarkable characteristics and has a promising future in terms of real sample analysis. The incorporation of NPs can advance several methods including surface assisted LDI-MS, and surface enhanced LDI-MS. These methods have advanced the detection of many thermally labile and nonvolatile biomolecules. Nanoparticles circumvent the drawbacks of conventional organic matrices for the analysis of small molecules. In most cases, NPs offer a clear background without interfering peaks, absence of fragmentation of thermally labile molecules, and allow the ionization of species with weak noncovalent interactions. Furthermore, an enhancement in sensitivity and selectivity can be achieved. NPs enable straightforward analysis of target species in a complex sample. This review (with 239 refs.) covers the progress made in laser-based mass spectrometry in combination with the use of metallic NPs (such as AuNPs, AgNPs, PtNPs, and PdNPs), NPs consisting of oxides and chalcogenides, silicon-based NPs, carbon-based nanomaterials, quantum dots, and metal-organic frameworks.
The sensitivity and efficiency of SALDI-MS or MALDI-MS is mainly dependent on the nature of matrix. A novel approach is proposed for one-pot synthesis of dopamine dithiocarbamate-functionalized gold nanoparticles (DDTC-Au NPs). Their application to quantification of small molecules by surface assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF-MS) and rapid identification of phosphopeptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is investigated. The synthesized DDTC-Au NPs were characterized by UV-visible and FT-IR spectroscopy, H(1)NMR, SEM and TEM. DDTC-Au NPs offers marked improvement on analyte ionization and effectively suppressed the background noise which leads to clean mass spectra. We also demonstrated the use of DDTC-Au NPs as affinity probes for selective enrichment of phosphopeptides from the solutions of microwave tryptic digested casein proteins. Compared with a conventional matrix, DDTC-Au NPs exhibited a high desorption/ionization efficiency for accurate quantification of small molecules including amino acid (glutathione), drugs (desipramine and enrofloxacin) and peptides (valinomycin and gramicidin D) and successfully utilized as novel affinity probes for straightforward and rapid identification of phosphopeptides from casein proteins (α-, β-casein and nonfat milk), showing a great potentiality to the real-time analysis. 相似文献
We report the first use of functionalized Ag2Se nanoparticles (NPs) as effective extracting probes for NPs-based liquid-phase microextraction (NPs-LPME) to analyze hydrophobic peptides and proteins from biological samples (urine and plasma) and soybean in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Surface modified functional groups such as octadecanethiol (ODT) and 11-mercaptoundecanoic acid (MUA) on Ag2Se NPs were found to play an important role for efficient extraction of peptides and proteins from test samples through hydrophobic interactions. The peptides can be efficiently extracted using functionalized Ag2Se NPs as extracting probes in the presence of high concentration of matrix interferences such as 4 M urea, 0.5% Triton X-100 and 3% NaCl. Ag2Se@ODT NPs have shown better extraction efficiency and detection sensitivity for peptides than Ag2Se@MUA NPs, bare Ag2Se NPs and conventional MALDI-MS. The LODs are 20-68 nM for valinomycin and 100-180 nM for gramicidin D using Ag2Se@ODT NPs-LPME in the MALDI-MS. The current approach is highly sensitive and the target analytes can be effectively isolated without sample loss and efficiently analyzed in MALDI-MS. 相似文献
The use of semiconductor cadmium sulphide nanoparticles (CdS NPs) capped with 4-aminothiophenol (ATP) and 11-mercaptoundecanoic acid (MUA) is described for the first time as matrices and as co-matrices for the analysis of peptides and proteins in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). UV-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied for the characterization of functionalized CdS NPs. The synthesized CdS-ATP and CdS-MUA NPs exhibit uniform size distribution with diameter of 15-25 nm and 20-30 nm, respectively. The -NH(2) (ATP) and -COOH (MUA) groups modified on the surfaces of CdS NPs provide ionizable moieties for efficient transfer of protons during the desorption/ionization of analytes. The functionalized CdS NPs have desirable properties for the analysis of peptides in reflectron MALDI-TOF-MS with suppressed background noise and increased mass resolution (4-13-fold) in linear MALDI-TOF-MS. The application of CdS-MUA NPs and SA as the co-matrices in MALDI-MS is demonstrated for the analysis of hydrophobic proteins from soybean. 相似文献
A simple method to synthesize electrostatically self-assembled azides on zinc sulfide nanoparticles (ZnS-N3 NPs) was described and then it was further applied as a multifunctional nanoprobe such as enriching, desalting, accelerating and separation-/washing free nanoprobes for rapid analysis of peptides and proteins and microwave assisted tryptic digested proteins in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The ZnS-N3 NPs were characterized by UV-vis, FT-IR, SEM and TEM spectroscopy. The ZnS-N3 NPs can effectively enrich signal intensities for 2-10 times for various peptides and proteins including HW6, insulin, ubiquitin, cytochrome c, lysozyme, myoglobin and bovine serum albumin (BSA) in MALDI-TOF MS. Furthermore, we also demonstrated that the ZnS-N3 NPs can serve as accelerating probes for microwave assisted tryptic digestion of proteins in MALDI-TOF MS. The applicability of the present method on complex sample analysis such as milk proteins from cow milk and ubiquitin and ubiquitin like proteins from oyster mushroom were also demonstrated. 相似文献
This paper reports a facile synthesis of molybdenum disulfide nanosheets/silver nanoparticles (MoS2/Ag) hybrid and its use as an effective matrix in negative ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The nanohybrid exerts a strong synergistic effect, leading to high performance detection of small molecule analytes including amino acids, peptides, fatty acids and drugs. The enhancement of laser desorption/ionization (LDI) efficiency is largely attributed to the high surface roughness and large surface area for analyte adsorption, better dispersibility, increased thermal conductivity and enhanced UV energy absorption as compared to pure MoS2. Moreover, both Ag nanoparticles and the edge of the MoS2 layers function as deprotonation sites for proton capture, facilitating the charging process in negative ion mode and promoting formation of negative ions. As a result, the MoS2/Ag nanohybrid proves to be a highly attractive matrix in MALDI-TOF MS, with desired features such as high desorption/ionization efficiency, low fragmentation interference, high salt tolerance, and no sweet-spots for mass signal. These characteristic properties allowed for simultaneous analysis of eight different drugs and quantification of acetylsalicylic acid in the spiked human serum. This work demonstrates for the first time the fabrication and application of a novel MoS2/Ag hybrid, and provides a new platform for use in the rapid and high throughput analysis of small molecules by mass spectrometry. 相似文献
Top-down synthesized TiO2 nanowires are presented as an ideal solid matrix to analyze small biomolecules at a m/z of less than 500. The TiO2 nanowires were synthesized as arrays using a modified hydrothermal process directly on the surface of a Ti plate. Finally, the feasibility of the TiO2 nanowires in the anatase phase as a solid matrix. The crystal and electronic structures of the top-down TiO2 nanowires were analyzed at each step of the hydrothermal process, and the optimal TiO2 nanowires were identified by checking their performance toward the ionization of analytes in surface-assisted laser desorption/ionization time-of-flight (SALDI-TOF) mass spectrometry. Finally, the feasibility of the TiO2 nanowires in the anatase phase as a solid matrix for SALDI-TOF mass spectrometry was demonstrated using eight types of amino acids and peptides as model analytes. 相似文献
This report focuses on the heterogeneous distribution of small molecules (e.g. metabolites) within dry deposits of suspensions and solutions of inorganic and organic compounds with implications for chemical analysis of small molecules by laser desorption/ionization (LDI) mass spectrometry (MS). Taking advantage of the imaging capabilities of a modern mass spectrometer, we have investigated the occurrence of “coffee rings” in matrix-assisted laser desorption/ionization (MALDI) and surface-assisted laser desorption/ionization (SALDI) sample spots. It is seen that the “coffee-ring effect” in MALDI/SALDI samples can be both beneficial and disadvantageous. For example, formation of the coffee rings gives rise to heterogeneous distribution of analytes and matrices, thus compromising analytical performance and reproducibility of the mass spectrometric analysis. On the other hand, the coffee-ring effect can also be advantageous because it enables partial separation of analytes from some of the interfering molecules present in the sample. We report a “hidden coffee-ring effect” where under certain conditions the sample/matrix deposit appears relatively homogeneous when inspected by optical microscopy. Even in such cases, hidden coffee rings can still be found by implementing the MALDI-MS imaging technique. We have also found that to some extent, the coffee-ring effect can be suppressed during SALDI sample preparation. 相似文献
The use of mass spectrometry (MS) to acquire molecular images of biological tissues and other substrates has developed into an indispensable analytical tool over the past 25 years. Imaging mass spectrometry technologies are widely used today to study the in situ spatial distributions for a variety of analytes. Early MS images were acquired using secondary ion mass spectrometry and matrix-assisted laser desorption/ionization. Researchers have also designed and developed other ionization techniques in recent years to probe surfaces and generate MS images, including desorption electrospray ionization (DESI), nanoDESI, laser ablation electrospray ionization, and infrared matrix-assisted laser desorption electrospray ionization. Investigators now have a plethora of ionization techniques to select from when performing imaging mass spectrometry experiments. This brief perspective will highlight the utility and relative figures of merit of these techniques within the context of their use in imaging mass spectrometry. 相似文献
A simple, rapid, straightforward and washing/separation free of in-solution digestion method for microwave-assisted tryptic digestion of proteins (cytochrome c, lysozyme and myoglobin) using bare TiO(2) nanoparticles (NPs) prepared in aqueous solution to serve as multifunctional nanoprobes in electrospray ionization mass spectrometry (ESI-MS) was demonstrated. The current approach is termed as 'on particle ionization/enrichment (OPIE)' and it can be applied in ESI-MS, atmospheric pressure-matrix-assisted laser desorption/ionization mass spectrometry (AP-MALDI-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The bare TiO(2) NPs can assist, accelerate and effectively enhance the digestion efficiency, sequence coverage and detection sensitivity of peptides for the microwave-assisted tryptic digestion of proteins in ESI-MS. The reason is attributed to the fact that proteins or partially digested proteins are easily attracted or concentrated onto the surface of TiO(2) NPs, resulting in higher efficiency of digestion reactions in the microwave experiments. Besides, the TiO(2) NPs could act as a microwave absorber to accelerate and enrich the protein fragments in a short period of time (40-60 s) from the microwave experiments in ESI-MS. Furthermore, the bare TiO(2) NPs prepared in aqueous solution exhibit high adsorption capability toward the protein fragments (peptides); thus, the OPIE approach for detecting the digested protein fragments via ESI and MALDI ionization could be achieved. The current technique is also a washing and separation-free technique for accelerating and enriching microwave-assisted tryptic digestion of proteins in the ESI-MS and MALDI-MS. It exhibits potential to be widely applied to biotechnology and proteome research in the near future. 相似文献
The application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) for the analysis of low molecular
weight (LMW) compounds, such as pharmacologically active constituents or metabolites, is usually hampered by employing conventional
MALDI matrices owing to interferences caused by matrix molecules below 700 Da. As a consequence, interpretation of mass spectra
remains challenging, although matrix suppression can be achieved under certain conditions. Unlike the conventional MALDI methods
which usually suffer from background signals, matrix-free techniques have become more and more popular for the analysis of
LMW compounds. In this review we describe recently introduced materials for laser desorption/ionization (LDI) as alternatives
to conventionally applied MALDI matrices. In particular, we want to highlight a new method for LDI which is referred to as
matrix-free material-enhanced LDI (MELDI). In matrix-free MELDI it could be clearly shown, that besides chemical functionalities,
the material’s morphology plays a crucial role regarding energy-transfer capabilities. Therefore, it is of great interest
to also investigate parameters such as particle size and porosity to study their impact on the LDI process. Especially nanomaterials
such as diamond-like carbon, C60 fullerenes and nanoparticulate silica beads were found to be excellent energy-absorbing materials in matrix-free MELDI. 相似文献
Nanomaterials have emerging importance in laser desorption ionization mass spectrometry (LDI–MS) with the ultimate objective
being to overcome some of the most important limitations intrinsically related to the use of conventional organic matrices
in matrix-assisted (MA) LDI–MS. This review provides a critical overview of the most recent literature on the use of gold
nanomaterials as non-conventional desorption ionization promoters in LDI–MS, with particular emphasis on bioanalytical applications.
Old seminal papers will also be discussed to provide a timeline of the most significant achievements in the field. Future
prospects and research needs are also briefly discussed. 相似文献
Biomimetic antireflective silicon nanocones array is used for analysis of small molecules by mass spectrometry. The role of the absorbed laser energy and its distribution in the laser desorption/ionization process has been investigated by varying the antireflective features precisely. By optimizing the antireflective silicon array, the absorbed laser energy can be channeled completely into the desorption/ionization of analytes. The optimized silicon array exhibits excellent performance to detect peptide, amino acid, drug molecule, and carbohydrate without any interference in the low-mass region. 相似文献