Computational Fluorescence Suppression in Shifted Excitation Raman Spectroscopy.

Fiber-based Raman spectroscopy in the context of in vivo biomedical application suffers from the presence of background fluorescence from the surrounding tissue that might mask the crucial but inherently weak Raman signatures. One method that has shown potential for suppressing the background to reveal the Raman spectra is shifted excitation Raman spectroscopy (SER). SER collects multiple emission spectra by shifting the excitation by small amounts and uses these spectra to computationally suppress the fluorescence background based on the principle that Raman spectrum shifts with excitation while fluorescence spectrum does not. We introduce a method that utilizes the spectral characteristics of the Raman and fluorescence spectra to estimate them more effectively, and compare this approach against existing methods on real world datasets.

Tri-mode optical biopsy probe with fluorescence endomicroscopy, Raman spectroscopy, and time-resolved fluorescence spectroscopy.

We present an endoscopic probe that combines three distinct optical fibre technologies including: A high-resolution imaging fibre for optical endomicroscopy, a multimode fibre for time-resolved fluorescence spectroscopy, and a hollow-core fibre with multimode signal collection cores for Raman spectroscopy. The three fibers are all enclosed within a 1.2 mm diameter clinical grade catheter with a 1.4 mm end cap. To demonstrate the probe's flexibility we provide data acquired with it in loops of radii down to 2 cm. We then use the probe in an anatomically accurate model of adult human airways, showing that it can be navigated to any part of the distal lung using a commercial bronchoscope. Finally, we present data acquired from fresh ex vivo human lung tissue. Our experiments show that this minimally invasive probe can deliver real-time optical biopsies from within the distal lung - simultaneously acquiring co-located high-resolution endomicroscopy and biochemical spectra.

Evaluation of new or repurposed treatments for COVID-19: protocol for the phase Ib/IIa DEFINE trial platform.

INTRODUCTION: COVID-19 is a new viral-induced pneumonia caused by infection with a novel coronavirus, SARS-CoV-2. At present, there are few proven effective treatments. This early-phase experimental medicine protocol describes an overarching and adaptive trial designed to provide safety data in patients with COVID-19, pharmacokinetic (PK)/pharmacodynamic (PD) information and exploratory biological surrogates of efficacy, which may support further development and deployment of candidate therapies in larger scale trials of patients positive for COVID-19. METHODS AND ANALYSIS: Define is an ongoing exploratory multicentre-platform, open-label, randomised study. Patients positive for COVID-19 will be recruited from the following cohorts: (a) community cases; (b) hospitalised patients with evidence of COVID-19 pneumonitis; and (c) hospitalised patients requiring assisted ventilation. The cohort recruited from will be dependent on the experimental therapy, its route of administration and mechanism of action. Randomisation will be computer generated in a 1:1:n ratio. Twenty patients will be recruited per arm for the initial two arms. This is permitted to change as per the experimental therapy. The primary statistical analyses are concerned with the safety of candidate agents as add-on therapy to standard of care in patients with COVID-19. Secondary analysis will assess the following variables during treatment period: (1) the response of key exploratory biomarkers; (2) change in WHO ordinal scale and National Early Warning Score 2 (NEWS2) score; (3) oxygen requirements; (4) viral load; (5) duration of hospital stay; (6) PK/PD; and (7) changes in key coagulation pathways. ETHICS AND DISSEMINATION: The Define trial platform and its initial two treatment and standard of care arms have received a favourable ethical opinion from Scotland A Research Ethics Committee (REC) (20/SS/0066), notice of acceptance from The Medicines and Healthcare Products Regulatory Agency (MHRA) (EudraCT 2020-002230-32) and approval from the relevant National Health Service (NHS) Research and Development (R&D) departments (NHS Lothian and NHS Greater Glasgow and Clyde). Appropriate processes are in place in order to be able to consent adults with and without capacity while following the necessary COVID-19 safe procedures. Patients without capacity could be recruited via a legal representative. Witnessed electronic consent of participants or their legal representatives following consent discussions was established. The results of each study arm will be submitted for publication in a peer-reviewed journal as soon as the treatment arm has finished recruitment, data input is complete and any outstanding patient safety follow-ups have been completed. Depending on the results of these or future arms, data will be shared with larger clinical trial networks, including the Randomised Evaluation of COVID-19 Therapy trial (RECOVERY), and to other partners for rapid roll-out in larger patient cohorts. TRIAL REGISTRATION NUMBER: ISRCTN14212905, NCT04473053.

Sub millimetre flexible fibre probe for background and fluorescence free Raman spectroscopy.

Using the shifted-excitation Raman difference spectroscopy technique and an optical fibre featuring a negative curvature excitation core and a coaxial ring of high numerical aperture collection cores, we have developed a portable, background and fluorescence free, endoscopic Raman probe. The probe consists of a single fibre with a diameter of less than 0.25 mm packaged in a sub-millimetre tubing, making it compatible with standard bronchoscopes. The Raman excitation light in the fibre is guided in air and therefore interacts little with silica, enabling an almost background free transmission of the excitation light. In addition, we used the shifted-excitation Raman difference spectroscopy technique and a tunable 785 nm laser to separate the fluorescence and the Raman spectrum from highly fluorescent samples, demonstrating the suitability of the probe for biomedical applications. Using this probe we also acquired fluorescence free human lung tissue data.