Driven and Thermal Microparticle Rheology of Complex Biopolymer Systems

Mucociliary clearance is the process by which cilia actively transport mucus from the airway in order to keep a sterile environment in the lung. The flow properties, or the rheology, of mucus is of particular importance when considering mucus function since its modulus and viscosity result in net mucociliary transport. For example, when the protective layer of mucus is too thick, transport stops because the cilia cannot carry the increased load, as is the case in several lung-related pathologies like cystic fibrosis, COPD, and asthma. The 3DFM is an instrument we designed, implemented, and validated in our lab. Evolving significantly over the last several years, the 3DFM is a system that images and manipulates biological specimens in all three spatial dimensions at microscopic length scales. When we subject a bead embedded in a fluid to an applied force, its spatiotemporal response depends on the rheological properties of the surrounding fluid. For example, in a Newtonian fluid the terminal velocity of a bead is inversely proportional to the fluid viscosity. Applying magnetic forces to micron sized spheres or even rod-shaped particles (i.e. bacteria or magnetically permeable nanoparticles) allows us to study the correspondence (or lack thereof) between micro-physical measurements and the canonical characterizations of macroscopic rheology techniques like cone-and-plate rheometers. Also, such a microscale technique is desirable since it is often difficult to acquire sufficient volume of a purified biological sample to test using macroscale rheological techniques such as cone and plate. Biological systems can also be highly heterogeneous and present a challenge for any measurement technique because of this variability. Finally, we must mention the necessity of performing measurements at relevant length scales since evolutionary pressure is the driving force for these biopolymer systems. Here I will argue the usefulness of driven microbead rheology (DMBR) as a measurement technique for soft biopolymer solutions. I begin by explaining the effects of probe shape and make first observations regarding a preference in particle shape for drug delivery. Next, I describe the fundamental measurements in our DMBR system and offer data for well-characterized Newtonian and homogeneous viscoelastic polymer solutions. I will present experimental results and will establish the ability of DMBR as a technique for measuring both linear and nonlinear properties of non-Newtonian fluids. Finally, there will be particular attention on strain-thickening, a dynamic and nonlinear rheological property of mucus that I have observed for the first time at the microscale, making it interesting in understanding mucociliary clearance

Analysis-preserving video microscopy compression via correlation and mathematical morphology: MICROSCOPY VIDEO COMPRESSION BASED ON CORRELATION AND MATHEMATICAL MORPHOLOGY

The large amount video data produced by multi-channel, high-resolution microscopy system drives the need for a new high-performance domain-specific video compression technique. We describe a novel compression method for video microscopy data. The method is based on Pearson's correlation and mathematical morphology. The method makes use of the point-spread function (PSF) in the microscopy video acquisition phase. We compare our method to other lossless compression methods and to lossy JPEG, JPEG2000 and H.264 compression for various kinds of video microscopy data including fluorescence video and brightfield video. We find that for certain data sets, the new method compresses much better than lossless compression with no impact on analysis results. It achieved a best compressed size of 0.77% of the original size, 25× smaller than the best lossless technique (which yields 20% for the same video). The compressed size scales with the video's scientific data content. Further testing showed that existing lossy algorithms greatly impacted data analysis at similar compression sizes

An Automated High-throughput Array Microscope for Cancer Cell Mechanics

Changes in cellular mechanical properties correlate with the progression of metastatic cancer along the epithelial-to-mesenchymal transition (EMT). Few high-throughput methodologies exist that measure cell compliance, which can be used to understand the impact of genetic alterations or to screen the efficacy of chemotherapeutic agents. We have developed a novel array high-throughput microscope (AHTM) system that combines the convenience of the standard 96-well plate with the ability to image cultured cells and membrane-bound microbeads in twelve independently-focusing channels simultaneously, visiting all wells in eight steps. We use the AHTM and passive bead rheology techniques to determine the relative compliance of human pancreatic ductal epithelial (HPDE) cells, h-TERT transformed HPDE cells (HPNE), and four gain-of-function constructs related to EMT. The AHTM found HPNE, H-ras, Myr-AKT, and Bcl2 transfected cells more compliant relative to controls, consistent with parallel tests using atomic force microscopy and invasion assays, proving the AHTM capable of screening for changes in mechanical phenotype

A high throughput array microscope for the mechanical characterization of biomaterials

In the last decade, the emergence of high throughput screening has enabled the development of novel drug therapies and elucidated many complex cellular processes. Concurrently, the mechanobiology community has developed tools and methods to show that the dysregulation of biophysical properties and the biochemical mechanisms controlling those properties contribute significantly to many human diseases. Despite these advances, a complete understanding of the connection between biomechanics and disease will require advances in instrumentation that enable parallelized, high throughput assays capable of probing complex signaling pathways, studying biology in physiologically relevant conditions, and capturing specimen and mechanical heterogeneity. Traditional biophysical instruments are unable to meet this need. To address the challenge of large-scale, parallelized biophysical measurements, we have developed an automated array high-throughput microscope system that utilizes passive microbead diffusion to characterize mechanical properties of biomaterials. The instrument is capable of acquiring data on twelve-channels simultaneously, where each channel in the system can independently drive two-channel fluorescence imaging at up to 50 frames per second. We employ this system to measure the concentration-dependent apparent viscosity of hyaluronan, an essential polymer found in connective tissue and whose expression has been implicated in cancer progression

Can creatine supplementation improve body composition and objective physical function in rheumatoid arthritis patients? A randomised controlled trial.

OBJECTIVE: Rheumatoid cachexia (muscle wasting) in rheumatoid arthritis (RA) patients contributes to substantial reductions in strength and impaired physical function. The objective of this randomised control trial was to investigate the effectiveness of oral creatine (Cr) supplementation in increasing lean mass and improving strength and physical function in RA patients. METHOD: In a double-blind design, 40 RA patients, were randomised to either 12 weeks supplementation of Cr or placebo. Body composition (dual energy x-ray absorptiometry, DXA, and bioelectrical impedance spectroscopy, BIS), strength and objectively-assessed physical function were measured at: baseline, day 6, week 12 and week 24. Data analysis was performed by ANCOVA. RESULTS: Creatine supplementation increased appendicular lean mass (ALM; a surrogate measure of muscle mass) by 0.52 (± 0.13) kg (P = 0.004 versus placebo), and total LM by 0.60 (± 0.37) kg (P = 0.158). The change in LM concurred with the gain in intracellular water (0.64 ± 0.22 L, P = 0.035) measured by BIS. Despite increasing ALM, Cr supplementation, relative to placebo, failed to improve isometric knee extensor (P = 0.408), handgrip strength (P = 0.833), or objectively-assessed physical function (P's = 0.335 - 0.764). CONCLUSION: In patients with RA, creatine supplementation increased muscle mass, but not strength or objective physical function. No treatment-related adverse effects were reported suggesting that Cr supplementation may offer a safe and acceptable adjunct treatment for attenuating muscle loss; this treatment may be beneficial for patients suffering from severe rheumatoid cachexia. This article is protected by copyright. All rights reserved

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

A high throughput array microscope for the mechanical characterization of biomaterials

In the last decade, the emergence of high throughput screening has enabled the development of novel drug therapies and elucidated many complex cellular processes. Concurrently, the mechanobiology community has developed tools and methods to show that the dysregulation of biophysical properties and the biochemical mechanisms controlling those properties contribute significantly to many human diseases. Despite these advances, a complete understanding of the connection between biomechanics and disease will require advances in instrumentation that enable parallelized, high throughput assays capable of probing complex signaling pathways, studying biology in physiologically relevant conditions, and capturing specimen and mechanical heterogeneity. Traditional biophysical instruments are unable to meet this need. To address the challenge of large-scale, parallelized biophysical measurements, we have developed an automated array high-throughput microscope system that utilizes passive microbead diffusion to characterize mechanical properties of biomaterials. The instrument is capable of acquiring data on twelve-channels simultaneously, where each channel in the system can independently drive two-channel fluorescence imaging at up to 50 frames per second. We employ this system to measure the concentration-dependent apparent viscosity of hyaluronan, an essential polymer found in connective tissue and whose expression has been implicated in cancer progression

Australia's north, Australia's future: A vision and strategies for sustainable economic, ecological and social prosperity in northern Australia

The release of the United Nations Sustainable Development Goals and the Paris Climate Change agreement highlighted the importance of global sustainability internationally. Here, we outline a vision and strategies for developing northern Australia that demonstrate how a focus on sustainable prosperity can both expand historical approaches and current government plans and integrate the biophysical realities with the social, political, and cultural characteristics of the region. We highlight examples of the significant horizontal and vertical integration opportunities that this expanded vision and related strategies provide for (a) land (carbon farming, targeted food production systems, and native title arrangements); (b) water (water resources management); (c) energy (renewable energy production, storage, and distribution); (d) workforce (culturally appropriate ecotourism, Indigenous ranger programs, and protected area management); (e) knowledge services (health care and innovative employment opportunities); and (f) governance (greater participatory governance). We found that realisation of even 10% of these emerging opportunities over the next 10years alone could result in economic growth worth over AUD 15 billion and 15,000+ jobs for northern Australia as well as the further ecological and social benefits derived from a sustainable prosperity strategy