Assisted Laser Desorption Ionization Mass Research Articles

Spherical covalent-organic framework-assisted laser desorption ionization mass spectrometry reveals the promotional effect of triphenyl phosphate on breast cancer in mice

Triphenyl phosphate (TPP), a wide-used organophosphate flame retardants (OPFRs), is suspected to be a risk factor for the female-specific cancers, but underlying toxicity mechanisms of environmentally relevant dose exposure remain unclear. Herein, a strategy of spherical covalent organic framework (TPB-BPTP-COF)-assisted laser desorption ionization mass spectrometry (LDI-MS), which benefited from fast analysis speed, facile sample preprocessing, and high throughput, was proposed for unveiling the biomarkers of breast cancer (BC) and the relationship between TPP exposure and progression of BC in mice by serum metabolism analysis. The results displayed that 13 metabolites associated with BC development were up-regulated in experimental group versus healthy control mice. Moreover, long-term exposure to environmentally relevant doses of TPP was found to promote BC, mainly by affecting glycolysis/gluconeogenesis, pyrimidine metabolism, pantothenic acid and CoA biosynthesis, and β-alanine metabolism. This work proved the potential application of COFs as LDI-MS substrates in analyzing complex biological samples, and also revealed the risk of long-term low-dose exposure to TPP in the development of BC.

Using matrix assisted laser desorption ionisation mass spectrometry combined with machine learning for vaccine authenticity screening

The global population is increasingly reliant on vaccines to maintain population health with billions of doses used annually in immunisation programmes. Substandard and falsified vaccines are becoming more prevalent, caused by both the degradation of authentic vaccines but also deliberately falsified vaccine products. These threaten public health, and the increase in vaccine falsification is now a major concern. There is currently no coordinated global infrastructure or screening methods to monitor vaccine supply chains. In this study, we developed and validated a matrix-assisted laser desorption/ionisation-mass spectrometry (MALDI-MS) workflow that used open-source machine learning and statistical analysis to distinguish authentic and falsified vaccines. We validated the method on two different MALDI-MS instruments used worldwide for clinical applications. Our results show that multivariate data modelling and diagnostic mass spectra can be used to distinguish authentic and falsified vaccines providing proof-of-concept that MALDI-MS can be used as a screening tool to monitor vaccine supply chains.

High toxinogenic potential of Staphylococcus aureus from wild ungulates in Brandenburg, Germany with a low level of antibiotic resistance.

Data regarding the occurrence and virulence of Staphylococcus (S.) aureus in wild living animals is rare. However, S. aureus may carry a multitude of virulence factors and express resistance to several antimicrobial substances. Handling game meat may thus lead to serious infections or food poisoning. The aim of this study was to provide insights into the occurrence and characteristics of S. aureus in wild ungulates from Brandenburg, Germany. Nasal swabs of externally healthy-looking wild boars, roe, fallow and red deer were collected in hunts during season 2021/2022 and analyzed for S. aureus by selective enrichment. Species were determined using matrix assisted laser desorption ionization mass spectrometry and tested for phenotypic antimicrobial resistance. Whole-genome sequencing was conducted for genotyping, determination of virulence associated genes and analysis of phylogenetic relationships. S. aureus were recovered from approximately 8% of nasal swabs. However, the strains were only obtained from the sampled wild ruminants. S. aureus isolates were associated with sequence types (ST) 1, ST30, ST133, ST425, ST582 and ST6238. Isolates of ST1 clustered closely together in the phylogenetic analysis. Genes encoding staphylococcal enterotoxin (SE) or SE-like (SEl) were found in 14/17 isolates. In particular, a seh gene was present in 12/17 isolates. Moreover, two isolates harbored a multiplicity of genes encoding SE or SEl. In addition, the toxic shock syndrome toxin encoding tst gene was detected in one isolate. This isolate was resistant to penicillin and cefoxitin and accordingly harbored the blaZ gene. Wild ungulates intended for human consumption may carry potentially virulent S. aureus. In one case, the close phylogenetic relationship of S. aureus isolates indicates a possible intraspecific spread within a common territory. However, for others, the origin or the spread pattern can only be inferred. Handling of animals or their carcasses might contribute to staphylococcal infections in humans. Moreover, food poisoning due to SE producing strains may occur, if recommended hygiene practices are not applied during processing of game meat.

Effect of dynamic exclusion and the use of FAIMS, DIA and MALDI-mass spectrometry imaging with ion mobility on amyloid protein identification

Amyloidosis is a disease characterized by local and systemic extracellular deposition of amyloid protein fibrils where its excessive accumulation in tissues and resistance to degradation can lead to organ failure. Diagnosis is challenging because of approximately 36 different amyloid protein subtypes. Imaging methods like immunohistochemistry and the use of Congo red staining of amyloid proteins for laser capture microdissection combined with liquid chromatography tandem mass spectrometry (LMD/LC–MS/MS) are two diagnostic methods currently used depending on the expertise of the pathology laboratory. Here, we demonstrate a streamlined in situ amyloid peptide spatial mapping by Matrix Assisted Laser Desorption Ionization–Mass Spectrometry Imaging (MALDI-MSI) combined with Trapped Ion Mobility Spectrometry for potential transthyretin (ATTR) amyloidosis subtyping. While we utilized the standard LMD/LC–MS/MS workflow for amyloid subtyping of 31 specimens from different organs, we also evaluated the potential introduction in the MS workflow variations in data acquisition parameters like dynamic exclusion, or testing Data Dependent Acquisition combined with High-Field Asymmetric Waveform Ion Mobility Spectrometry (DDA FAIMS) versus Data Independent Acquisition (DIA) for enhanced amyloid protein identification at shorter acquisition times. We also demonstrate the use of Mascot’s Error Tolerant Search and PEAKS de novo sequencing for the sequence variant analysis of amyloidosis specimens.

Multi-spectroscopic characterization of organic salt components in medicinal plant

The characterization of structure of organic salts in complex mixtures has been a difficult problem in analytical chemistry. In the analysis of Scutellariae Radix (SR), the pharmacopoeia of many countries stipulates that the quality control component is baicalin (≥9% by high performance liquid chromatography (HPLC)). The component with highest response in SR was also baicalin detected by liquid chromatography-mass spectrometry (LC-MS). However, in the attenuated total reflection Fourier transform infrared spectroscopy, the carbonyl peak of glucuronic acid of baicalin did not appear in SR. The results of element analysis, time of flight secondary ion mass spectrometry, matrix assisted laser desorption ionization mass spectrometry and solid-state nuclear magnetic resonance all supported the existence of baicalin magnesium salt. Based on this, this study proposes an analysis strategy guided by infrared spectroscopy and combined with multi-spectroscopy techniques to analyze the structure of organic salt components in medicinal plant. It is meaningful for the research of mechanisms, development of new drugs, and quality control.

Application of graphite carbon black assisted-laser desorption ionization-mass spectrometry for soy sauce product discrimination.

In a previous study, we developed a novel analytical method to directly and simultaneously detect taste- and odor-active compounds using graphite carbon black (GCB)-assisted laser desorption ionization mass spectrometry (LDI-MS). In this study, we aimed to evaluate food quality using a variety of soy sauces using the method to discriminate each product. Graphite carbon black-laser desorption ionization-mass spectrometry allowed the provision of hundreds of MS peaks derived from soy sauces in both positive and negative modes without any tedious sample pretreatments. Principal component analysis using the obtained MS peaks clearly distinguished three soy sauce products based on the manufacturing countries (Japan, China, and India). Moreover, this method identified distinct MS peaks for discrimination, which significantly correlated with their quantitative amounts in the products. Thus, GCB-LDI-MS analysis was established as a simple and rapid technique for food analysis, illustrating the chemical patterns of food products.

Abstract 7088: MALDI-IHC high-plex protein biomarker imaging for fast, non-iterative identification of lung carcinoma subtypes

Abstract Lung cancer is the second most common cancer worldwide, with over 2.2 million new cases in 2020 and is the leading cause of cancer-related deaths worldwide. Most lung cancer (80-85%) is non-small cell (NSCLC), comprising mostly adenocarcinoma and squamous cell carcinoma, while roughly 10-15% of lung cancer is small cell lung cancer (SCLC), also termed neuroendocrine lung cancer. Subtype identification is critical for determining treatment, and with limited samples, it is critical to get the most data possible from each tissue section. NSCLC subtypes can be treated with chemotherapy or targeted drugs, whereas SCLC tends to respond best to a combination of chemotherapy and radiation. While there have been many improvements in the detection and treatment of lung carcinoma, the immuno-histochemical (IHC) confirmation of subtype remains a prolonged and often iterative process. To overcome this limitation, we have developed a new IHC approach which uses antibodies labeled with novel photocleavable mass-tags combined with matrix assisted laser desorption ionization (MALDI) mass spectrometry imaging. The approach, termed MALDI-IHC, provides fast (1 hr/cm2 imaging time) and highly multiplexed IHC (100+-plex) without the need for iterative cycling procedures. Here, we present a 20+-plex panel for the determination of subtype in lung cancer. An antibody panel comprised of established clinical biomarkers was developed to differentiate between the lung carcinoma subtypes and provide potentially prognostic information. This included markers for adenocarcinoma (TTF-1, Napsin A), squamous cell carcinoma (p40, CK5), and small cell lung cancer (CD56, Chromogranin A and Synaptophysin), as well as general carcinoma markers for t cells, b cells, macrophages, and fibroblasts These markers were first validated individually by immunofluorescence and then compared to MALDI-IHC on annotated tissues. Here we present an overview of the antibody validation for the 20+-plex lung carcinoma panel. Biomarker presence and peak signal intensity for the various subtypes was then determined using pathologist classified tissues for normal lung, adenocarcinoma, squamous cell carcinoma and small cell lung cancer. We report application of the MALDI-IHC approach to the simultaneous determination of lung carcinoma subtypes on a 99-core human lung tissue microarray (TMA) comprised of normal, normal adjacent, cancer adjacent, and cancerous tissues. Moreover, because MALDI-IHC is a non-destructive process, it can be followed by conventional H&E staining on the same tissue section for accurate co-registration of traditional pathology annotations with the highly multiplexed MALDI-IHC results. In the future, even larger, 100+-plex antibody panels can be used for precision medicine on a wide range of cancers, in order to determine the molecular subtypes and guide treatment paths. Citation Format: Catherine A. Kita, Kristina Schwamborn, Gargey Yagnik, Kenneth J. Rothschild, Mark J. Lim. MALDI-IHC high-plex protein biomarker imaging for fast, non-iterative identification of lung carcinoma subtypes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7088.

Multimodal, PSMA-Targeted, PAMAM Dendrimer-Drug Conjugates for Treatment of Prostate Cancer: Preclinical Evaluation.

Prostate cancer (PC) is the second most common cancer and the fifth most frequent cause of cancer death among men. Prostate-specific membrane antigen (PSMA) expression is associated with aggressive PC, with expression in over 90% of patients with metastatic disease. Those characteristics have led to its use for PC diagnosis and therapies with radiopharmaceuticals, antibody-drug conjugates, and nanoparticles. Despite these advancements, none of the current therapeutics are curative and show some degree of toxicity. Here we present the synthesis and preclinical evaluation of a multimodal, PSMA-targeted dendrimer-drug conjugate (PT-DDC), synthesized using poly(amidoamine) (PAMAM) dendrimers. PT-DDC was designed to enable imaging of drug delivery, providing valuable insights to understand and enhance therapeutic response. The PT-DDC was synthesized through consecutive conjugation of generation-4 PAMAM dendrimers with maytansinoid-1 (DM1) a highly potent antimitotic agent, Cy5 infrared dye for optical imaging, 2,2',2"-(1,4,7-triazacyclononane-1,4,7-triyl)triacetic acid (NOTA) chelator for radiolabeling with copper-64 and positron emission tomography tomography/computed tomography (PET/CT), lysine-urea-glutamate (KEU) PSMA-targeting moiety and the remaining terminal primary amines were capped with butane-1,2-diol. Non-targeted control dendrimer-drug conjugate (Ctrl-DDC) was formulated without conjugation of KEU. PT-DDC and Ctrl-DDC were characterized using high-performance liquid chromatography, matrix assisted laser desorption ionization mass spectrometry and dynamic light scattering. In vitro and in vivo evaluation of PT-DDC and Ctrl-DDC were carried out in isogenic human prostate cancer PSMA+PC3 PIP and PSMA-PC3 flu cell lines, and in mice bearing the corresponding xenografts. PT-DDC was stable in 1×PBS and human blood plasma and required glutathione for DM1 release. Optical, PET/CT and biodistribution studies confirmed the in vivo PSMA-specificity of PT-DDC. PT-DDC demonstrated dose-dependent accumulation and cytotoxicity in PSMA+ PC3 PIP cells, and also showed growth inhibition of the corresponding tumors. PT-DDC did not accumulate in PSMA- PC3 flu tumors and did not inhibit their growth. Ctrl-DDC did not show PSMA specificity. In this study, we synthesized a multimodal theranostic agent capable of delivering DM1 and a radionuclide to PSMA+ tumors. This approach holds promise for enhancing image-guided treatment of aggressive, metastatic subtypes of prostate cancer.

Characterization of Riemerella anatipestifer Strains Isolated from Various Poultry Species in Poland.

Riemerella anatipestifer (R. anatipestifer) is one of the common pathogens found in poultry flocks, resulting in serious economic losses for the poultry industry due to high mortality, reduced growth rate, poor feed conversion, increased condemnations, and high treatment costs. The aim of this study was to phenotypically characterize phylogenetic relationships and assess the presence of resistance gene strains of R. anatipestifer obtained from various poultry species in Poland. A total of 57 isolates of Riemerella were included in this study. A polymerase chain reaction (PCR) and matrix assisted laser desorption ionization mass spectrometry (MALDI-TOF MS) were used for identification of the strains. The phylogenetic relationship of the R. anatipestifer isolates was determined by analysing the rpoB gene sequence. The susceptibility to antibiotics was evaluated by minimum inhibitory concentration (MIC) in liquid media. All of the field strains of R. anatipestifer were grouped into one of two clades resulting from rpoB gene sequencing. High MIC50 and MIC90 values were obtained for gentamycin, amikacin, and colistin. Low MIC50 and MIC90 values were obtained for amoxicillin cefuroxime, cefoperazone, piperacillin, and trimethoprim/sulfamethoxazole. Among the resistance genes, tet(X) and ermF were identified most frequently. This is the first phenotypic characterization of R. anatipestifer strains obtained from poultry flocks in Poland.

Strategies for MALDI-MS method development to investigate different pharmaceutical drug modalities

High-throughput screening (HTS) is an ultra-high throughput tool that allows the identification of diverse, pharmaceutically active compounds in the early stages of drug discovery, by enabling chemists to screen reactions at micromole/nanomole scales. To eliminate the bottleneck arising from analysis of large libraries, Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) can be utilized as a compatible, ultra-fast, label-free, analysis tool. Upon integrating this technique with suitable liquid handling robots that can accurately spot matrices and analytes on a MALDI plate, chemical reactions can be screened at a sampling rate of <1 s per sample. While earlier efforts to improve MALDI-HTS applications were geared towards the development of automation and data processing tools, a systematic method development study across different drug modalities was needed to understand the contribution of different parameters such as MALDI matrices, choice of matrices, additives, and solvent composition, on MALDI-MS signal intensities of analytes. The current study will demonstrate the importance of initial MALDI-MS method development on small molecules, peptides, antibodies, and antibody drug conjugates. This study is designed as a starting point for MALDI-MS signal optimization, which can eventually lead to the development of effective MALDI-HTS methods for various modalities, thus paving the way for a wide range of applications, including but not limited to conformational analysis.

Automated High-Throughput Matrix Assisted Laser Desorption Ionization Mass Spectrometry Methodology for Formulation Assessment of Polyethylene-Glycol-Conjugated Cytokine Proteins

Biological therapeutics are major contributors to the pharmaceutical pipeline and continue to grow in sales and scope. Additionally, the field's understanding of cancer biology has advanced such that biopharmaceuticals can harness the power of the immune system for oncology treatments. Several of these novel therapeutics are engineered versions of naturally occurring proteins designed to improve therapeutic properties including potency, target engagement and half-life extension. Cytokines, such as interferons and interleukins, are a broad class of signaling proteins which modulate the body's immune response; engineered cytokines have entered the clinic as promising new immuno-oncology therapies. While these therapies hold great promise, their additional structural complexity introduces analytical challenges, and traditional analytical platforms may be ill-suited to effectively assess product development risks. Further, the pharmaceutical industry relies on streamlining approaches for high-throughput experimentation to achieve speed and efficiency for the discovery and development of new modalities. These demands necessitate the use of state-of-the-art techniques to rapidly characterize these new modalities and guide process development and optimization. Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) is a rapid, sensitive and automatable technique amenable for high-throughput analysis of proteins. In this work, we have developed an automated MALDI-MS platform to prepare, acquire and analyze molecular degradation in engineered PEGylated cytokines formulation samples. This orthogonal technique integrated seamlessly with current developability risk assessment workflows, ultimately enabling selection of a final formulation strategy for clinical development.

Non-invasive screening of breast cancer from fingertip smears—a proof of concept study

Breast cancer is a global health issue affecting 2.3 million women per year, causing death in over 600,000. Mammography (and biopsy) is the gold standard for screening and diagnosis. Whilst effective, this test exposes individuals to radiation, has limitations to its sensitivity and specificity and may cause moderate to severe discomfort. Some women may also find this test culturally unacceptable. This proof-of-concept study, combining bottom-up proteomics with Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDI MS) detection, explores the potential for a non-invasive technique for the early detection of breast cancer from fingertip smears. A cohort of 15 women with either benign breast disease (n = 5), early breast cancer (n = 5) or metastatic breast cancer (n = 5) were recruited from a single UK breast unit. Fingertips smears were taken from each patient and from each of the ten digits, either at the time of diagnosis or, for metastatic patients, during active treatment. A number of statistical analyses and machine learning approaches were investigated and applied to the resulting mass spectral dataset. The highest performing predictive method, a 3-class Multilayer Perceptron neural network, yielded an accuracy score of 97.8% when categorising unseen MALDI MS spectra as either the benign, early or metastatic cancer classes. These findings support the need for further research into the use of sweat deposits (in the form of fingertip smears or fingerprints) for non-invasive screening of breast cancer.

Leaves of Cannabis sativa and their trichomes studied by DESI and MALDI mass spectrometry imaging for their contents of cannabinoids and flavonoids.

In recent years, industrial production of Cannabis sativa has increased due to increased demand of medicinal products based on the plant. In these medicinal products, it is mainly the contents of cannabinoids like THCA and CBDA which are of interest, but also the flavonoids of C. sativa have pharmaceutical interest. The primary aim is to study the distribution of the different cannabinoids in leaves of C. sativa and specifically to which extent they are located on the trichomes found on the surface of C. sativa leaves. Desorption electrospray ionization (DESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) provide non-targeted imaging of numerous compounds in the same experiment. Therefore, the distribution of flavonoids is also mapped in the same experiments. Fan leaves from C. sativa were imaged in the lateral dimension using direct DESI-MSI as well as indirect DESI-MSI via a porous PTFE surface using pixel sizes of 150-200 μm. For cross sections of sugar leaves, MALDI-MSI was performed at 20 μm pixel size. From indirect DESI-MSI experiments, a connection was made between the cannabinoid CBGA and capitate-stalked trichomes. Other cannabinoids like THCA/CBDA (isomers, which are not resolved in an MSI experiment) were also detected in the capitate-stalked trichomes, but in addition to this also in the small glandular trichomes. MALDI-MSI experiments on cross sections of sugar leaves confirmed that the cannabinoids were not an integral part of the leaf tissue itself, but originated from the trichomes on the surface of the leaf. The study provides visual evidence that the cannabinoids are produced and accumulated in the trichomes of C. sativa leaves.

Targeting of colorectal cancer organoids with zoledronic acid conjugated to the anti-EGFR antibody cetuximab

BackgroundAntibody-drug conjugates (ADC) are essential therapeutic options to treat solid and hematological cancers. The anti-epidermal growth factor-receptor (EGFR) antibody cetuximab (Cet) is used for the therapy of colorectal carcinoma (CRC)....

Aptamer-conjugated graphene oxide-based surface assisted laser desorption ionization mass spectrometry for selective extraction and detection of Aβ1-42 in an Alzheimer's disease SH-SY5 cell model.

The generation and accumulation of amyloid-beta peptide (Aβ1–42) in amyloid plaques are key characteristics of Alzheimer’s disease (AD); thus, specific detection of Aβ1–42 is essential for the diagnosis and treatment of AD. Herein, an aptamer-conjugated graphene oxide (Apt-GO) sensor was synthesized by π-π and hydrophobic interactions using thiol poly (ethylene glycol) amine (SH-PEG-NH2) as a spacer unit. Then, it was applied to selective capture of Aβ1–42, and the resulting complex was directly analyzed by surface-assisted laser desorption ionization mass spectrometry (SALDI-MS). The results revealed that the Apt-GO could enhance the detection specificity and reduce non-specific adsorption. This method was validated to be sensitive in detecting Aβ1–42 at a low level in human serum (ca. 0.1 μM) within a linear range from 0.1 to 10 μM. The immobilizing amount of aptamer on the GO was calculated to be 36.1 nmol/mg (RSD = 11.5%). In conclusion, this Apt-GO-based SALDI-MS method was sensitive and efficient in selective extraction and detection of Aβ1–42, which proved to be a good option for early AD diagnosis.

In depth investigation of the capabilities and limitations of combined proteomic-MALDI MS based approach for the forensic detection of blood

For the past 7 years, Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDI MS) based methods have been developed and published for the forensic detection of blood in stains and fingermarks. However, in the view of adoption in an operational context, further investigation into the capabilities and limitations of this approach must be conducted. The refinement and testing of this approach must also be tailored to the requirements of the end users, enabling them to address the specific circumstances most encountered in a forensic scenario. The present study delves deeper into the assessment of the applicability of MALDI MS based strategy for the reliable and robust detection of human blood through: (i) a semi-qualitative assessment of the sensitivity of the method, (ii) a wider investigation of the compatibility of the method with the prior application of commonly used presumptive tests and (iii) assessment of the specificity of the method (when blood is present in mixture with other biofluids) and of its robustness, by assessing blood detection from a range of porous materials. The findings strengthen the evidence supporting the adoption of MALDI MS based approaches as a confirmatory test for the forensic detection of human blood in an operational context.

A multimodal pipeline using NMR spectroscopy and MALDI-TOF mass spectrometry imaging from the same tissue sample.

NMR spectroscopy and matrix assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) are both commonly used to detect large numbers of metabolites and lipids in metabolomic and lipidomic studies. We have demonstrated a new workflow, highlighting the benefits of both techniques to obtain metabolomic and lipidomic data, which has realized for the first time the combination of these two complementary and powerful technologies. NMR spectroscopy is frequently used to obtain quantitative metabolite information from cells and tissues. Lipid detection is also possible with NMR spectroscopy, with changes being visible across entire classes of molecules. Meanwhile, MALDI MSI provides relative measures of metabolite and lipid concentrations, mapping spatial information of many specific metabolite and lipid molecules across cells or tissues. We have used these two complementary techniques in combination to obtain metabolomic and lipidomic measurements from triple-negative human breast cancer cells and tumor xenograft models. We have emphasized critical experimental procedures that ensured the success of achieving NMR spectroscopy and MALDI MSI in a combined workflow from the same sample. Our data show that several phospholipid metabolite species were differentially distributed in viable and necrotic regions of breast tumor xenografts. This study emphasizes the power of combined NMR spectroscopy-MALDI imaging to advance metabolomic and lipidomic studies.

Forensic Discrimination of Differentially Sourced Animal Blood Using a Bottom-Up Proteomics Based MALDI MS Approach.

Recently published work has reported the development and application of a bottom-up proteomic approach to distinguish between human and animal blood (down to animal species level), by rapid screening using Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDI MS). In that study, it was additionally observed that intravenous animal blood exhibits different spectral profiles from blood collected within the animal chest cavity as well as from the diluted blood collected within packets of meat. In this follow-up study we explored the resulting hypothesis that, depending on how blood is shed or collected, protein biomarker profiles vary to the extent of systematically permitting a distinction between possible sources of blood (for example, flesh wound versus packaged meat). This intelligence may be important in reconstructing the dynamics of the crime. The combination of statistical analysis and tandem mass spectrometry has yielded additional animal blood markers as well as confirming the ability to correctly determine the animal species from which blood derived, regardless of the retailer selling it (amongst the five investigated). These data confirm the initial hypothesis and demonstrate the opportunity for the proteomics-MALDI combined approach to provide additional intelligence to the investigation of violent crimes when examining blood evidence.

Aptamer-Conjugated Graphene Oxide Based Surface Assisted Laser Desorption Ionization Mass Spectrometry for Selective Extraction and Detection of Aβ1-42

Aptamer-Conjugated Graphene Oxide Based Surface Assisted Laser Desorption Ionization Mass Spectrometry for Selective Extraction and Detection of Aβ1-42

Black Mesoporous TiO2 Nanoparticles for Enhancing Surface Assisted Laser Desorption and Ionization in Mass Spectrum Analysis

AbstractSurface assisted laser desorption ionization mass spectrometry (SALDI‐MS) is a powerful analytical technology for the high‐throughput detection of metabolites, drugs, and other bioactive molecules. The performance of SALDI‐MS in enhancing molecules desorption and ionization mainly depends on the surface properties of matrix utilized. Here, black titanium dioxide (B‐TiO2) nanoparticle is used for the first time as a novel matrix for enhancing laser desorption and ionization (LDI) and demonstrates significant advantages over white titanium dioxide (W‐TiO2). Further, the black mesoporous TiO2 coated Fe3O4 magnetic nanoparticles (B‐mTiO2 MNPs) are designed and prepared, which possess a high molar absorption coefficient, strong magnetic response, higher specific surface area, and ample phosphorylation binding sites. The B‐mTiO2 MNPs exhibit a superior ionization efficiency, low background signal, and good reproducibility (RSD &lt; 10%) in the analysis of compounds with different molecular weights and practical bio‐sample. Salt tolerance of B‐mTiO2 MNPs up to 10 mm PBS, meanwhile, B‐mTiO2 MNPs also provides excellent enrichment efficiency for phosphopeptides (the detection limit low to 5 × 10−10 M).