In situ derivatization of Au nanoclusters via aurophilic interactions of a triphenylphosphine gold(i) salt with neurotransmitters and their rapid MALDI-TOF-MS detection in mice brain tissue extracts

A reactive matrix for in situ chemical derivatisation and specific detection of cis-diol compounds by matrix-assisted laser desorption/ionisation mass spectrometry

Analysis of cis-diol compounds is essential, because they play important roles in cosmetics, food, pharmaceuticals, and living organisms. Herein, we describe the development of a matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) method to analyse cis-diol compounds. In this method, a 6-borono-1-methylquinoline-1-ium (BMQI) reactive matrix was designed for in situ derivatisation of cis-diol compounds based on the boronate affinity interaction between boronic acid and cis-diol groups. Compared to traditional commercial matrices and other boronic acid reagents, BMQI can significantly accelerate the desorption/ionisation process, improve reproducibility, exhibit free background interference, and enhance signal intensity in the analysis of various cis-diol compounds even for amounts as low as 1 nmol. The BMQI-assisted laser desorption/ionisation mass spectrometry (LDI-MS) was successfully applied to the rapid screening and identification of sugar alcohols in different sugar-free foods. This work provides an alternative method to the LDI-MS analysis of cis-diol-containing molecules, and the method can be extended to other food samples and biofluids.

Nanomaterials-assisted metabolic analysis toward in vitro diagnostics

In vitro diagnostics (IVD) has played an indispensable role in healthcare system by providing necessary information to indicate disease condition and guide therapeutic decision. Metabolic analysis can be the primary choice to facilitate the IVD since it characterizes the downstream metabolites and offers real-time feedback of the human body. Nanomaterials with well-designed composition and nanostructure have been developed for the construction of high-performance detection platforms toward metabolic analysis. Herein, we summarize the recent progress of nanomaterials-assisted metabolic analysis and the related applications in IVD. We first introduce the important role that nanomaterials play in metabolic analysis when coupled with different detection platforms, including electrochemical sensors, optical spectrometry, and mass spectrometry. We further highlight the nanomaterials-assisted metabolic analysis toward IVD applications, from the perspectives of both the targeted biomarker quantitation and untargeted fingerprint extraction. This review provides fundamental insights into the function of nanomaterials in metabolic analysis, thus facilitating the design of next-generation diagnostic devices in clinical practice.

Advances in MALDI Mass Spectrometry Imaging Single Cell and Tissues

Compared with conventional optical microscopy techniques, mass spectrometry imaging (MSI) or imaging mass spectrometry (IMS) is a powerful, label-free analytical technique, which can sensitively and simultaneously detect, quantify, and map hundreds of biomolecules, such as peptides, proteins, lipid, and other organic compounds in cells and tissues. So far, although several soft ionization techniques, such as desorption electrospray ionization (DESI) and secondary ion mass spectrometry (SIMS) have been used for imaging biomolecules, matrix-assisted laser desorption/ionization (MALDI) is still the most widespread MSI scanning method. Here, we aim to provide a comprehensive review of MALDI-MSI with an emphasis on its advances of the instrumentation, methods, application, and future directions in single cell and biological tissues.

Sensitive detection of clenbuterol by hybrid iridium/silicon nanowire-enhanced laser desorption/ionization mass spectrometry

There is increasing demand for anti-doping drug monitoring in sports and food safety checks by developing sensitive and fast analytical methods. Here we report the development of hybrid Ir/SiNW as a new MALDI matrix for the detection of small molecules. This matrix is characterized by sufficient UV absorption, low-noise background, and high efficiency in ionization of small molecules. Sensitive detection of clenbuterol (LOD: 0.18 pmol) and a variety of other small molecules has been achieved using the Ir/SiNW matrix with a reproducible performance. Compared to the individual components separately, the matrix of hybrid Ir/SiNW synthesized via in situ growth can promote the MS signal intensity by up to 10 fold under identical experimental conditions. We provide a unique mechanism for the high performance of the hybrid Ir/SiNW matrix with the characteristic properties of hydrogen atom transfer and enhanced protonation at the interface of the hybrid nanostructures. Our approach of using a hybrid Ir/SiNW matrix enables detection of clenbuterol quantitatively in complicated biological samples and in vivo experiments, promising a useful tool for food security and anti-doping drug monitoring in sports.