Label-Free SERS Sensors for Real-Time Monitoring of Tyrosine Phosphorylation.

Dysregulation of receptor tyrosine kinases (RTKs) has been shown to correlate with cancer cell proliferation and drug resistance. Thus, monitoring the activity of RTKs at a chemical level could provide new biomedical insights and methods to assess the drug efficacy. However, direct monitoring of kinase activity is challenging and most commonly relies on techniques such as Western blotting and ELISAs.

SERS Microsensors for the Study of pH Regulation in Cystic Fibrosis Patient-Derived Airway Cultures.

Acidification of the airway surface liquid in the respiratory system could play a role in the pathology of Cystic Fibrosis, but its low volume and proximity to the airway epithelium make it a challenging biological environment in which to noninvasively collect pH measurements. To address this challenge, we explored surface enhanced Raman scattering microsensors (SERS-MS), with a 4-mercaptobenzoic acid (MBA) pH reporter molecule, as pH sensors for the airway surface liquid of patient-derived in vitro models of the human airway. Using air-liquid interface (ALI) cultures to model the respiratory epithelium, we show that SERS-MS facilitates the optical measurement of trans-epithelial pH gradients between the airway surface liquid and the basolateral culture medium.

SERS microsensors for pH measurements in the lumen and ECM of stem cell derived human airway organoids.

Patient derived organoids have the potential to improve the physiological relevance of disease models. However, the 3D architecture of these self-assembled cellular structures makes probing their biochemistry more complex than in traditional 2D culture. We explore the application of surface enhanced Raman scattering microsensors (SERS-MS) to probe local pH gradients within patient derived airway organoid cultures.

Automatic Cocrystal Detection by Raman Spectral Deconvolution-Based Novelty Analysis.

Cocrystals are important molecular adducts that have many advantages as a means of modifying the physicochemical properties of active pharmaceutical ingredients, including taste masking and improved solubility, bioavailability, and stability. As a result, the discovery of new cocrystals is of great interest to commercial drug discovery programs. Time-consuming manual analysis of the large volumes of data that emerge from large-scale cocrystal screening programs of up to 1000s of preparations poses a challenge.

Fabrication of a Wearable Flexible Sweat pH Sensor Based on SERS-Active Au/TPU Electrospun Nanofibers.

Development of wearable sensing platforms is essential for the advancement of continuous health monitoring and point-of-care testing. Eccrine sweat pH is an analyte that can be noninvasively measured and used to diagnose and aid in monitoring a wide range of physiological conditions. Surface-enhanced Raman scattering (SERS) offers a rapid, optical technique for fingerprinting of biomarkers present in sweat.

A SERS-Active Electrospun Polymer Mesh for Spatially Localized pH Measurements of the Cellular Microenvironment.

Extracellular pH (pHe) is an important chemical factor in many cellular processes and disease pathologies. The routine sampling of pHe could lead to innovative advances in therapeutics. To this end, we have fabricated a novel gold-coated polymer mesh, which facilitates the real-time measurement of pHe via surface-enhanced Raman scattering (SERS).

Time-correlated single photon Raman spectroscopy at megahertz repetition rates.

Significant improvements in time-correlated single photon counting (TCSPC) Raman spectroscopy acquisition times can be achieved through exploitation of megahertz (MHz) laser repetition rates. We have developed a TCSPC Raman spectroscopy system based on a high peak power (>40) pulsed laser, a high pulse repetition rate (40 MHz), a custom /1.5 spectrometer, and a 512 spectral channel × 16 time bin single photon avalanche diode line sensor.

Noninvasive Detection of Ischemic Vascular Damage in a Pig Model of Liver Donation After Circulatory Death.

Background And Aims: Liver graft quality is evaluated by visual inspection prior to transplantation, a process highly dependent on the surgeon's experience. We present an objective, noninvasive, quantitative way of assessing liver quality in real time using Raman spectroscopy, a laser-based tool for analyzing biomolecular composition.

Approach And Results: A porcine model of donation after circulatory death (DCD) with normothermic regional perfusion (NRP) allowed assessment of liver quality premortem, during warm ischemia (WI) and post-NRP.

Intracellular redox potential is correlated with miRNA expression in MCF7 cells under hypoxic conditions.

Hypoxia is a ubiquitous feature of cancers, encouraging glycolytic metabolism, proliferation, and resistance to therapy. Nonetheless, hypoxia is a poorly defined term with confounding features described in the literature. Redox biology provides an important link between the external cellular microenvironment and the cell's response to changing oxygen pressures.

Human cystic fibrosis monocyte derived macrophages display no defect in acidification of phagolysosomes when measured by optical nanosensors.

Background: Defective macrophage phagolysosomal acidification is implicated in numerous lung diseases including Cystic Fibrosis (CF) and may contribute to defective pathogen killing. Conflicting reports relating to phagolysosomal pH in CF macrophages have been published, in part related to the use of pH-sensitive fluorescent probes where potential inadequacies in experimental design can be a contributing factor (e.g.

Untargeted Metabolite Mapping in 3D Cell Culture Models Using High Spectral Resolution FT-ICR Mass Spectrometry Imaging.

Multicellular tumor spheroids (MTS) are a well-established model system for drug development and are a valuable in vitro research tool for use prior to employing animal models. These 3D-cell cultures are thought to display chemical gradients of oxygen and nutrients throughout their structure, giving rise to distinct microenvironments in radial layers, thus, mimicking the pathophysiological environment of a tumor. Little is known about the localized distributions of metabolites within these microenvironments.

Ultra-low background Raman sensing using a negative-curvature fibre and no distal optics.

Measuring Raman spectra through an optical fibre is usually complicated by the high intrinsic Raman scatter of the fibre material. Common solutions such as the use of multiple fibres and distal optics are complex and bulky. We demonstrate the use of single novel hollow-core negative-curvature fibres (NCFs) for Raman and surface-enhanced Raman spectroscopy (SERS) sensing using no distal optics.

Dual purpose fibre - SERS pH sensing and bacterial analysis.

The exploitation of fibre based Raman probes has been challenged by often complicated fabrication procedures and difficulties in reproducibility. Here, we have demonstrated a simple and cost-effective approach for sensing pH through an optical fibre, by employing a wax patterned filter paper-based substrate for surface enhanced Raman spectroscopy (SERS). Through this method, high reproducibility between fibres was achieved.

Raman spectroscopy investigation of biochemical changes in tumor spheroids with aging and after treatment with staurosporine.

There has been increasing use of in vitro cell culture models that more realistically replicate the three-dimensional (3D) environment found in vivo. Multicellular tumor spheroids (MTS) using cell lines or patient-derived organoids have become an important in vitro drug development tool, where cells are grown in a 3D "sphere" that exhibits many of the characteristics found in vivo. Significantly, MTS develop gradients in nutrients and oxygen, commonly found in tumors that contribute to therapy resistance.

MALDI Matrix Application Utilizing a Modified 3D Printer for Accessible High Resolution Mass Spectrometry Imaging.

Successful matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) relies on the selection of the most appropriate matrix and optimization of the matrix application parameters. In order to achieve reproducible high spatial-resolution imaging data, several commercially available automated matrix application platforms have become available. However, the high cost of these commercial matrix sprayers is restricting access into this emerging research field.

Raman spectroscopy and regenerative medicine: a review.

The field of regenerative medicine spans a wide area of the biomedical landscape-from single cell culture in laboratories to human whole-organ transplantation. To ensure that research is transferrable from bench to bedside, it is critical that we are able to assess regenerative processes in cells, tissues, organs and patients at a biochemical level. Regeneration relies on a large number of biological factors, which can be perturbed using conventional bioanalytical techniques.

Inhaled Nanoparticles Accumulate at Sites of Vascular Disease.

The development of engineered nanomaterials is growing exponentially, despite concerns over their potential similarities to environmental nanoparticles that are associated with significant cardiorespiratory morbidity and mortality. The mechanisms through which inhalation of nanoparticles could trigger acute cardiovascular events are emerging, but a fundamental unanswered question remains: Do inhaled nanoparticles translocate from the lung in man and directly contribute to the pathogenesis of cardiovascular disease? In complementary clinical and experimental studies, we used gold nanoparticles to evaluate particle translocation, permitting detection by high-resolution inductively coupled mass spectrometry and Raman microscopy. Healthy volunteers were exposed to nanoparticles by acute inhalation, followed by repeated sampling of blood and urine.

Targeted SERS nanosensors measure physicochemical gradients and free energy changes in live 3D tumor spheroids.

Use of multicellular tumor spheroids (MTS) to investigate therapies has gained impetus because they have potential to mimic factors including zonation, hypoxia and drug-resistance. However, analysis remains difficult and often destroys 3D integrity. Here we report an optical technique using targeted nanosensors that allows in situ 3D mapping of redox potential gradients whilst retaining MTS morphology and function.

Correction: Measuring the effects of fractionated radiation therapy in a 3D prostate cancer model system using SERS nanosensors.

Correction for 'Measuring the effects of fractionated radiation therapy in a 3D prostate cancer model system using SERS nanosensors' by Victoria L. Camus, et al., Analyst, 2016, 141, 5056-5061.

Measuring the effects of fractionated radiation therapy in a 3D prostate cancer model system using SERS nanosensors.

Multicellular tumour spheroids (MTS) are three-dimensional cell cultures that possess their own microenvironments and provide a more meaningful model of tumour biology than monolayer cultures. As a result, MTS are becoming increasingly used as tumor models when measuring the efficiency of therapies. Monitoring the viability of live MTS is complicated by their 3D nature and conventional approaches such as fluorescence often require fixation and sectioning.