Rapid and Robust Workflows Using Different Ionization, Computation, and Visualization Approaches for Spatial Metabolome Profiling of Microbial Natural Products in .

Ambient mass spectrometry (MS) technologies have been applied to spatial metabolomic profiling of various samples in an attempt to both increase analysis speed and reduce the length of sample preparation. Recent studies, however, have focused on improving the spatial resolution of ambient approaches. Finer resolution requires greater analysis times and commensurate computing power for more sophisticated data analysis algorithms and larger data sets.

Storing liquid chromatographic separations on surface energy traps: decoupling the LC and the mass spectrometer.

We report a micro-fractionation device for high performance liquid chromatography-mass spectrometry to archive chromatographic separations on an array of optimized surface energy traps (SETs). The method has the potential to significantly alter nanoflow LC-MS workflow, decoupling separation and analysis. The wetting characteristics of the SETs cause the HPLC eluent stream to spontaneously split into droplet microfractions.

SpectraX: A Straightforward Tool for Principal Component Analysis-Based Spectral Analysis.

The analysis of complex spectra is an important component of direct/ambient mass spectrometry (MS) applications such as natural product screening. Unlike chromatography-based metabolomics or proteomics approaches, which rely on software and algorithms, the work of spectral screening is mostly performed manually in the initial stages of research and relies heavily on the experience of the analyst. As a result, throughput and spectral screening reliability are problematic when dealing with large amounts of data.

Micro "Hyper-Channels" on Laser-Refined Cellulose Structures.

Controlled liquid transportation is widely applied in both academia and industry. However, liquid transport applications are limited by parameters such as driving forces, precision, and velocity. Herein, a simple laser-refining technology is presented to produce micro "hyper-channels".

Open Port Interface for Coupling Capillary Electrophoresis and Mass Spectrometry: Performance Evaluation for Capillary Isoelectric Focusing.

Capillary electrophoresis (CE) combined with mass spectrometry (MS) is a powerful analytical technique that utilizes the resolving power of CE and the mass-detection capabilities of MS. In many cases, CE is coupled to MS via a sheath-flow interface (SFI). This interface has a simple design and can be easily constructed; however, it often suffers from issues such as MS signal suppression, interference of MS and CE electrical circuits, and the inability to set an optical point of detection close to the capillary end due to the specific design of the coupling union.

LMJSSP for analysis of prophylactic lubricants, spermicides and residues.

DNA evidence in sexual assault cases have proven increasingly difficult to obtain and analyse due to increased condom use. With more interest in alternatives to DNA evidence, prophylactic lubricants, spermicides and residues may be interesting prospects. Current interest in the analysis of prophylactic residues focuses on the evaluation and identification of lubricants and constituents, primarily through gas chromatography or Fourier transform infrared spectroscopy.

3D printer platform and conductance feedback loop for automated imaging of uneven surfaces by liquid microjunction-surface sampling probe mass spectrometry.

Rationale: Molecular imaging of samples using mass spectrometric techniques, such as matrix-assisted laser desorption ionization or desorption electrospray ionization, requires the sample surface to be even/flat and sliced into thin sections (c. 10 μm). Furthermore, sample preparation steps can alter the analyte composition of the sample.

Hyperspectral Visualization-Based Mass Spectrometry Imaging by LMJ-SSP: A Novel Strategy for Rapid Natural Product Profiling in Bacteria.

Mass spectrometry imaging (MSI) has been widely used to discover natural products (NPs) from underexplored microbiological sources. However, the technique is limited by incompatibility with complicated/uneven surface topography and labor-intensive sample preparation, as well as lengthy compound profiling procedures. Here, liquid micro-junction surface sampling probe (LMJ-SSP)-based MSI is used for rapid profiling of natural products from Gram-negative marine bacteria on nutrient agar media without any sample preparation.

Investigating electrochemical deposition of gold on commercial off-the-shelf 3-D printing materials towards developing sensing applications.

The COVID-19 pandemic highlighted the inaccessibility of quick and affordable clinical diagnostics. This led to increased interest in creating low-cost portable electrochemical (EC) devices for environmental monitoring and clinical diagnostics. One important perspective is to develop new fabrication methods for functional and low-cost electrode chips.

Discontinuously Dewetting Solvent Arrays: Droplet Formation and Poly-Synchronous Surface Extraction for Mass Spectrometry Imaging Applications.

We describe a new liquid tissue stamping method called poly-synchronous surface extraction (PSSE) that utilizes an omniphobic substrate patterned with hydrophilic surface energy traps (SETs), which when wet with a solvent form a dense microdroplet array. When contacted with a tissue sample, each droplet locally extracts analytes from the tissue surface, which subsequentially can be analyzed by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-IMS) or ambient ionization-MS techniques. Optimization of the patterned surface with six different solvents was carried out to increase the droplet density, height, and reproducibility of volume deposition.

Realizing new designs of multiplexed electrode chips by 3-D printed masks.

Creating small and portable analytical methods is a fast-growing field of research. Devices capable of performing bio-analytical detection are especially desirable with the onset of the global pandemic. Lab-on-a-chip (LOC) technologies, including rapid point-of-care (POC) devices such as glucose sensors, are attractive for applications in resource-poor settings.

Rapid Mass Spectrometric Calibration and Standard Addition Using Hydrophobic/Hydrophilic Patterned Surfaces and Discontinuous Dewetting.

The rapid calibration chip (RCC) is a device that uses the fast and reproducible wetting behavior of hydrophilic/hydrophobic patterned surfaces to confine a series of differently sized droplets on a substrate to obtain a calibration curve. Multiple series of droplets can be formed within seconds by dipping an RCC into a calibration solution. No pipetting, sequential droplet deposition, or advanced equipment is required.

Application of Intraoperative Mass Spectrometry and Data Analytics for Oncological Margin Detection, A Review.

Objective: A common phase of early-stage oncological treatment is the surgical resection of cancerous tissue. The presence of cancer cells on the resection margin, referred to as positive margin, is correlated with the recurrence of cancer and may require re-operation, negatively impacting many facets of patient outcomes. There exists a significant gap in the surgeon's ability to intraoperatively delineate between tissues.

The liquid micro junction-surface sampling probe (LMJ-SSP); a versatile ambient mass spectrometry interface.

Ambient ionization methods have become important tools in mass spectrometry. The LMJ-SSP can significantly simplify/reduce lengthy sample preparation requirements associated with mass spectrometry analysis. Samples may be introduced through direct contact, insertion and droplet injection, enabling applications from drug discovery and surface analysis to tissue profiling and metabolic mapping.

Fabrication and characterization of laser-heated, multiplexed electrospray emitter.

We present a one-step fabrication method for a new multiplexed electrospray emitter with nine parallel micronozzles. The nozzles were formed by wet chemical etching of the end of a microstructured silica fiber containing nine 10 μm flow channels. By carefully adjusting the water flow through the channels while etching, we controlled the shape of the conical micronozzles and were able to obtain conditions under which the micronozzles, together with the flow channels, formed optical micro-axicon lenses.

Ice recrystallization inhibition activity varies with ice-binding protein type and does not correlate with thermal hysteresis.

Ice-binding proteins (IBPs) inhibit the growth of ice through surface adsorption. In some freeze-resistant fishes and insects, circulating IBPs serve as antifreeze proteins to stop ice growth by lowering the freezing point. Plants are less able to avoid freezing and some use IBPs to minimize the damage caused in the frozen state by ice recrystallization, which is the growth of large ice grains at the expense of small ones.

Detection of Opioids on Mail/Packages Using Open Port Interface Mass Spectrometry (OPI-MS).

Opioids (and their more potent synthetic analogues) are used therapeutically as effective pain killers; however, recreational use and consequent overdoses are implicated in the deaths of thousands of people across the world annually. Trafficking of opioids and other illegal drugs through international mail has become a significant challenge for law enforcement personnel. Hundreds of millions of letters are sorted by the U.

Open sessile droplet viscometer with low sample consumption.

This paper reports a portable viscometer that requires less than 10 μL of sample for a measurement. Using a two-droplet Laplace-induced pumping system on an open microfluidic substrate, the device measures the viscosity of a liquid by determining the time required for one droplet to completely pump into a second droplet. The pumping behaviour follows the Hagen-Poiseuille and Laplace relations where the flow rate, Q, is proportional to the liquid's kinematic viscosity, μ.

Hydrophobic/hydrophilic patterned surfaces for directed evaporative preconcentration.

The deposition of micro- and nanolitre volumes is crucial in sessile droplet microfluidic systems. Several techniques exist for the fabrication of surfaces with patterned wettabilities; however, many of these fabrication techniques are time-consuming and complex. Here, we present a device that allows for deposition of multiple droplets within seconds followed by directed evaporative preconcentration.

Light activated synthesis of the atomically precise fluorescent silver cluster Ag(Capt).

Metal clusters of gold and silver with highly tunable optical and electronic properties are attractive candidates for next generation medical imaging and therapy. Of these two most commonly studied metals, silver clusters often exhibit superior optical properties (i.e.

Facile actuation of aqueous droplets on a superhydrophobic surface using magnetotactic bacteria for digital microfluidic applications.

Magnetic actuation provides a low-cost, simple method for droplet manipulation on a digital microfluidic platform. The impetus to move the droplets on a low friction surface can come from internal superparamagnetic particles or paramagnetic salts. Recently, the use of microbes for bio-actuation has been established, where the thrust produced by the microbes can be exploited to exert the force required for droplet movement.

Facile Actuation of Organic and Aqueous Droplets on Slippery Liquid-Infused Porous Surfaces for the Application of On-Chip Polymer Synthesis and Liquid-Liquid Extraction.

Digital microfluidics employs water-repellant surfaces to exquisitely manipulate droplets of water for chemical analysis. However, the actuation and manipulation of organic droplets is still relatively unexplored as it is significantly more difficult to synthesize organic-repellent surfaces compared to water-repellent surfaces. Here, we present the fabrication of slippery liquid-infused porous surfaces (SLIPS) based on a porous polymer monolithic approach.

Reliable identification of prostate cancer using mass spectrometry metabolomic imaging in needle core biopsies.

Metabolomic profiling can aid in understanding crucial biological processes in cancer development and progression and can also yield diagnostic biomarkers. Desorption electrospray ionization coupled to mass spectrometry imaging (DESI-MSI) has been proposed as a potential adjunct to diagnostic surgical pathology, particularly for prostate cancer. However, due to low resolution sampling, small numbers of mass spectra, and little validation, published studies have yet to test whether this method is sufficiently robust to merit clinical translation.

Organic-free, versatile sessile droplet microfluidic device for chemical separation using an aqueous two-phase system.

This work presents a novel portable, versatile sessile droplet microfluidic (SDMF) device to perform liquid manipulation operations such as confining, splitting and colorimetric detection. Furthermore, chemical isolations based on an aqueous two-phase system (ATPS) for separating an analyte of choice from a complicated sample matrix can be carried out. ATPS extractions can replace conventional liquid-liquid extractions and take away the need for harmful organic solvents.