Yuchen Xiang

• Research Associate at Imperial College London

Brillouin imaging (BI) for micromechanical characterization of tissues and biomaterials is a fast-developing field of research with a strong potential for medical diagnosis of disease-modified tissues and cells. Although the principles of BI imply its compatibility with in vivo and in situ measurements, the integration of BI with a flexible cathete...

Brillouin spectroscopy can suffer from low signal-to-noise ratios (SNRs). Such low SNRs can render common data analysis protocols unreliable, especially for SNRs below ∼10. In this work we exploit two denoising algorithms, namely maximum entropy reconstruction (MER) and wavelet analysis (WA), to improve the accuracy and precision in determination o...

Brillouin imaging (BI) has become a valuable tool for micromechanical material characterisation, thanks to extensive progress in instrumentation in the last few decades. This powerful technique is contactless and label-free, thus making it especially suitable for biomedical applications. Nonetheless, to fully harness the non-contact and non-destruc...

Brillouin imaging relies on the reliable extraction of subtle spectral information from hyperspectral datasets. To date, the mainstream practice has been to use line fitting of spectral features to retrieve the average peak shift and linewidth parameters. Good results, however, depend heavily on sufficient signal‐to‐noise ratio and may not be appli...

Background: Metabolites, especially lipids, have been shown to be promising therapeutic targets. In conjugation with genes and proteins they can be used to identify phenotypes of disease and support the development of targeted treatments. The majority of clinically collected tissue samples are stored in formalin-fixed and paraffin embedded (FFPE) b...

Hyperspectral imaging is a powerful bioimaging tool which can uncover novel insights, thanks to its sensitivity to the intrinsic properties of materials. However, this enhanced contrast comes at the cost of system complexity, constrained by an inherent trade-off between spatial resolution, spectral resolution, and imaging speed. To overcome this li...

Laser desorption ionization (LDI) is generally considered to be an inferior ionization modality to matrix assisted LDI (MALDI), providing information solely on lipids with low sensitivity. The current study demonstrates that the combination of ambient LDI with in-source surface-induced declustering provides sensitivity and chemical coverage compara...

To establish infections in human hosts, Pseudomonas aeruginosa must overcome innate immune-generated oxidative stress, such as the hypochlorous acid (HOCl) produced by neutrophils. We set out to find specific biomarkers of oxidative stress through the development of a protocol for the metabolic profiling of P. aeruginosa cultures grown in the prese...

Sustained smouldering, or low-grade activation, of myeloid cells is a common hallmark of several chronic neurological diseases, including multiple sclerosis¹. Distinct metabolic and mitochondrial features guide the activation and the diverse functional states of myeloid cells². However, how these metabolic features act to perpetuate inflammation of...

We report a 2.94 μm OPA with ~100 ps pulse duration, 400 nJ pulse energy and a 500 kHz repetition rate, which enables high resolution (≤10 μm) laser desorption-based mass spectrometry imaging of biological tissue.

To establish infections in human hosts, Pseudomonas aeruginosa must overcome innate immune generated oxidative stress, such as the hypochlorous acid (HOCl) produced by neutrophils. We set out to find specific biomarkers of oxidative stress through the development of a protocol for the metabolic profiling of P. aeruginosa cultures grown in the prese...

The genomic landscape of colorectal cancer (CRC) is shaped by inactivating mutations in tumour suppressors such as APC, and oncogenic mutations such as mutant KRAS. Here we used genetically engineered mouse models, and multimodal mass spectrometry-based metabolomics to study the impact of common genetic drivers of CRC on the metabolic landscape of...

Mass spectrometry imaging (MSI) has been a key driver of groundbreaking discoveries in a number of fields since its inception more than 50 years ago. Recently, MSI development trends have shifted towards ambient MSI (AMSI) as the removal of sample-preparation steps and the possibility of analysing biological specimens in their natural state have dr...

Laser desorption ionisation (LDI) is generally considered to be an inferior ionisation modality to matrix assisted LDI (MALDI), providing information solely on lipids with low sensitivity. The current study demonstrates that the combination of ambient LDI with in-source surface-induced declustering provides sensitivity and chemical coverage compara...

Laser desorption ionisation (LDI) is generally considered to be an inferior ionisation modality to matrix assisted LDI (MALDI), providing information solely on lipids with low sensitivity. The current study demonstrates that the combination of ambient LDI with in-source surface-induced declustering provides sensitivity and chemical coverage compara...

With colorectal cancer (CRC) being the second most common cause of cancer-related deaths worldwide ¹ , there is an urgent need for better diagnostic tools and new, more targeted therapies. Here we used genetically engineered mouse models (GEMMs), and multimodal mass spectrometry-based metabolomics to study the impact of common genetic drivers of CR...

Background: Colorectal adenoma detection using non-invasive faecal-based biomarkers is not yet feasible. Our primary aim was to identify differential metabolomic signatures of colorectal adenomas in faecal samples using a Liquid Chromatography Mass Spectrometry (LCMS) assay. The secondary aim was to translate this assay to an Ambient Mass ionizatio...

Optical microscopy has long been the gold standard to analyse tissue samples for the diagnostics of various diseases, such as cancer. The current diagnostic workflow is time-consuming and labour-intensive, and manual annotation by a qualified pathologist is needed. With the ever- increasing number of tissue blocks and the complexity of molecular di...

Oncogenic KRAS mutations and inactivation of the APC tumor suppressor co-occur in colorectal cancer (CRC). Despite efforts to target mutant KRAS directly, most therapeutic approaches focus on downstream pathways, albeit with limited efficacy. Moreover, mutant KRAS alters the basal metabolism of cancer cells, increasing glutamine utilization to supp...

Brillouin imaging relies on the reliable extraction of subtle spectral information from hyperspectral datasets. To date, the mainstream practice has been using line fitting of spectral features to retrieve the average peak shift and linewidth parameters. Good results, however, depend heavily on sufficient SNR and may not be applicable in complex sa...

Brillouin spectroscopy is a century-old technique that has recently received renewed interest, as modern instrumentation has transformed it into a powerful contactless and label-free probe of micromechanical properties for biomedical applications. In particular, to fully harness the non-contact and non-destructive nature of Brillouin imaging, there...

Brillouin imaging suffers from intrinsically low signal-to-noise ratios (SNR). Such low SNRs can render common data analysis protocols unreliable, especially for SNRs below $\sim10$. In this work we exploit two denoising algorithms, namely maximum entropy reconstruction (MER) and wavelet analysis (WA), to improve the accuracy and precision in deter...

Brillouin microscopy is a technique used to obtain information on the mechanical properties of samples in a non-contact manner. The sample is illuminated using a microscope objective lens (see Figure [1]) and the scattered light, containing both elastic (Rayleigh signal) and inelastic (Brillouin signal) components, is collected by the same lens and...

Brillouin imaging has recently emerged as a powerful technique for its ability to give insight to the mechanical properties of biomaterial. It exploits inelastic scattering of light by acoustic vibrations and maps the tissue stiffness point by point with micron resolution. The non-invasive, real-time nature of the measurements also makes it a poten...

The formation of hierarchical structures consisting of microstripe barriers decorated with nanorough ablated materials prepared by direct laser writing is described. Linear features of circa 25 μm width and 12 μm height are achieved on amorphous and crystalline titania and graphitic carbon films deposited on silicon. Ablated protrusions build up ba...