Applications of Microdroplet Technology for Algal Biotechnology

Background: Microfluidics allows manipulation of small volumes of fluids through channels with dimensions of tens to hundreds of micrometres. Microdroplet technology is a form of microfluidics in which small (10-200 μm diameter) monodispersed aqueous droplets are generated, manipulated and analysed in various ways. This multidisciplinary field provides an exciting new platform for single-cell studies of both eukaryotic microalgae and cyanobacteria, with considerable potential for enhancing algal biotechnology. Methods: Growth of several species of microalgae has been studied in detail using microfluidics and microdroplets, and individual cells have been screened and sorted according to lipid content or ethanol production. Here we provide an overview of the devices, and the range of technological advances that are being pursued. Conclusion: Microdroplet technology is an emerging technology platform that can be used in a variety of applications, including monitoring of growth characteristics at the single-cell level and high-throughput screening of algal populations. Microdroplet platforms are being developed that will allow determination of individual cell characteristics to allow screening across a population, and thus to identify and select candidate cells for biotechnological feedstocks. As the potential of this emerging technical platform is recognized, the technology will become more accessible, so that it can soon be adopted and used by researchers, without the need for specialized prior knowledge of microfluidics or expensive equipment. The platform is amenable for use with species of both microalgae and cyanobacteria.SAC acknowledges the funding from EC within the EU FP7 DEMA project, grant agreement n°309086. RB was supported by a doctoral training grant from the Engineering and Physical Sciences Research Council (EPSRC) of the UK.This is the author accepted manuscript. The final version is available from Bentham Science via http://dx.doi.org/10.2174/221155010566616020200255

Label-Free Analysis and Sorting of Microalgae and Cyanobacteria in Microdroplets by Intrinsic Chlorophyll Fluorescence for the Identification of Fast Growing Strains.

Microalgae and cyanobacteria are promising organisms for sustainable biofuel production, but several challenges remain to make this economically viable, including identification of optimized strains with high biomass productivity. Here we report on a novel methodology for the label-free screening and sorting of cyanobacteria and microalgae in a microdroplet platform. We show for the first time that chlorophyll fluorescence can be used to measure differences in biomass between populations of picoliter microdroplets containing different species of cyanobacteria, Synechocystis PCC 6803 and Synechococcus PCC 7002, which exhibit different growth dynamics in bulk culture. The potential and robustness of this label-free screening approach is further demonstrated by the screening and sorting of cells of the green alga Chlamydomonas reinhardtii encapsulated in droplets.Author R.J.B. was supported by a Doctoral Training Grant from the Engineering and Physical Sciences Research Council (EPSRC) of the UK (Reference EP/P505445/1), and author J.J.L. was in receipt of a studentship from the Biotechnology and Biological Sciences Research Council (BBSRC) of the U.K. as part of the Cambridge BBSRC-DTP Programme (Reference BB/J014540/1). Authors S.A.-C., C.A., and A.G.S. acknowledge funding from the EC within the FP7 DEMA project, Grant Agreement No. 309086, and authors Z.Y., C.A., and A.G.S. were in receipt of funding from BBSRC sLoLa Award Reference BB/L002957/1.This is the final version of the article. It first appeared from the American Chemical Society via https://doi.org/10.1021/acs.analchem.6b0236

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Research data supporting “Label-free analysis and sorting of microalgae and cyanobacteria in microdroplets by intrinsic chlorophyll fluorescence for the identification of fast growing strain”

Original or unprocessed data is provided in support of the article “Label-free analysis and sorting of microalgae and cyanobacteria in microdroplets by intrinsic chlorophyll fluorescence for the identification of fast growing strain”. The data is structured into three folders named: (1) ANDOR fluorescence images and spreadsheet; (2) Fluorescence spectra for cyano and microalgae used for Figure 1A and 1B; (3) Files compling the data for Figure 2, growth curves, chlorophyl detection in droplets and micrographs of cyano in dropletsEPSRC [EP/P505445/1], BBSRC [BB/J014540/1, sLoLa BB/L002957/1], EC [FP7 DEMA project: no. 309086