Low-viscosity Medium Research Articles

A near-infrared fluorescent probe for viscosity: Differentiating cancer cells from normal cells and dual-modal imaging in tumor mice

As a basic parameter of the intracellular microenvironment, viscosity is closely related to the development of cancer. Thus, it is necessary to utilize a sensitive tool to visualize the viscosity in tumor cells and mice, which is helpful for the diagnosis of cancer. Herein, a novel dual-modal probe (IX-V) that has a near-infrared fluorescence (NIRF) and photoacoustic (PA) response to viscosity is synthesized. In low viscosity media, the probe has no fluorescence. With the increase of viscosity, the fluorescence is produced in the near-infrared region due to the inhibition of the TICT process. At the same time, the probe shows different photoacoustic (PA) signals in different viscosity media. Most notably, the viscosity in tumor cells has been imaged successfully by the application of IX-V, and the probe can effectively distinguish cancer cells from normal cells co-cultured in one dish by the difference of fluorescence intensity. In addition, the probe has been used for dual-modal imaging (NIRF and PA) of viscosity in tumor mice, which provides a tool for exploring the relationship between viscosity and diseases. That is to say, IX-V can achieve complementary imaging effects and has great application prospects in the tumor diagnosis.

SELECTION OF SURFACTANT COMPOSITIONS FOR EXTRACTION RESIDUAL OIL RESERVES IN THE CONDITIONS OF HIGH-TEMPERATURE RESERVOIRS OF THE NEOCOMIAN DEPOSITS OF THE BS GROUP FORMATIONS OF WESTERN SIBERIA

Maintaining stable production at fields in the final stage of development requires the use of enhanced oil recovery (EOR) methods that allow the mobilization of residual oil in the reservoir. The introduction of EOR based on surfactant compositions in our country is complicated by the shortage of effective thermostable reagents, which are both expensive and difficult to access. Accordingly, the issues of their import substitution are quite acute. In this work, on the basis of available anionic surfactants and nonionic surfactants, it was possible to compose two multicomponent surfactant compositions (high- and low-concentrated) for the mobilization of residual oil in the conditions of high-temperature reservoirs of the neocomian sediments of the BS group of Western Siberia. To substantiate the the components of the composition and the method of its injection, a set of experimental physico-chemical and filtration testing methods was used. In particular, the interfacial tension, the kinetics of oil film washing, the phase behavior in the oil-watersurfactant system, as well as the pre-displacement of oil after flooding using a linear composite core model of the reservoir were determined. The developed surfactant composition is a synergistic mixture that reduces the interfacial tension at the water/oil boundary to ultra-low values (5·10–3 mN/m at 0.5 % surfactant), which makes it possible to form a low-viscosity medium phase of a type III microemulsion according to the Winsor classification and effectively solubilize oil. A method of injection of surfactant compositions is proposed, according to which a rim of sulfonated polyacrylamide (PAA) with the addition of diethanolamine is injected into the oil reservoir after surfactant edging. Analysis of the dynamics of oil displacement from the linear model of the reservoir after flooding suggested that as a result of the action of a surfactant composition with subsequent injection of a polymer solution with diethanolamine, capillary-trapped oil is first mobilized, and then film oil.

Theoretical analysis and experimental tests of tilting pad journal bearings with shoes made of polymer material and low-boiling liquid lubrication

Selecting the appropriate bearing system for the rotor requires a good knowledge of the available solutions and the operating conditions of the machine. For newly designed machinery operating in adverse conditions, selecting bearings that ensure correct and long-lasting operation can be extremely challenging. Difficulties increase when the machine's operating parameters are beyond the technical capabilities of available technical solutions. This article presents the course of the design process and results of numerical and experimental research of a prototype microturbine that uses an innovative rotor-bearing system. Due to the adverse operating conditions, new tilting pad journal bearings were designed, in which the sliding surfaces of the tilting pads were made of polymeric material and a low-viscosity medium in liquid form was used as the lubricating medium. The basic bearing parameters were selected and pre-checked by numerical calculations. The oil-free turbomachinery design thus developed was subjected to experimental testing under near-real conditions. The results of these tests confirmed that the developed bearings performed very well, ensuring stable operation of the high-speed rotor of the microturbine over a wide speed range. Despite the unfavourable lubrication conditions, no signs of bearing wear were observed. The results obtained indicate a new, promising direction for the development of bearing systems for turbomachinery, in which, with a suitable design of the bearings, a low-boiling working medium in liquid form can be used as a lubricating medium.

Apparent viscosity of high-density fluidized bed and synergistic effect of density and apparent viscosity on particle separation

ABSTRACT For gas-solid fluidization separation, mineral particles are separated under the joint action of bed density and apparent viscosity. In present study, the apparent viscosity of high-density binary mixture media was investigated by the falling ball method. Moreover, the significant effects of bed density and apparent viscosity on simulated mineral pellets and their interactions were investigated. The apparent viscosity model of high-density gas-solid fluidized beds was modified, and it was found that the Pearson correlation coefficient is 0.86. The results show that the apparent viscosity of high-density gas-solid fluidized bed decreases with increasing fluidization gas velocity. When the fluidization number is higher than 1.3, the apparent viscosity is basically stable in the range of 3.96–5.21 Pa·s. Under low apparent viscosity, when the pellet diameter is 20 mm and the density difference ∆ρ is greater than 0.27 g/cm3, gravity is the dominant factor affecting the settling behavior of the pellet. Under high apparent viscosity, the effect of viscous resistance on the settling behavior of pellets is dominant when the ∆ρ is less than 0.27 g/cm3. Based on the performed analyses, the low-viscosity medium can be selected for the separation of large mineral particles. Furthermore, for high-viscosity medium, the influence of bubbles on particle sedimentation can be effectively alleviated and it can be selected for the separation of small particles.

A double-blind controlled clinical trial to evaluate the effects of nasal therapy with Vrihatajivakadya oil on different viscosities in patients with migraine

BackgroundMigraine, characterized by pain of a specific type in one half of the head has a close resemblance with Ardhavabhedaka described in Ayurveda. Nasya karma (nasal therapy) with Vrihatajivakadya oil is indicated in Ardhavabhedaka. Low viscosity oil (LVO) and medium viscosity oil (MVO) prepared by Snehapaka (a specific Ayurveda method for preparation of oil) are advocated in different classical Ayurveda texts for N.karma. The objectivesThis study was done to assess the effects of Vrihatajivakadhya oil on different viscosities in N.karma for the better Ayurveda management of migraine. Material and methodsIn this double-blind randomized controlled trial a total of 90 patients were randomly divided into two groups for N.karma with oil of different viscosities. In the group treated with LVO, 44 patients completed their treatment and one patient was lost in follow-up. In another group treated with MVO, 45 patients were enrolled and completed the intervention. N.karma was done with this oil in the dose of 6 drops per nostril for the duration of 14 days for each participant. The follow-up was done on the 15th day and 45th days. The assessment was done by the Migraine Disability Assessment Score (MIDAS) and Migraine Specific Quality of Life Assessment scale. ResultDuring the trial, significant improvement in both the groups on both parameters was observed. No adverse event was noticed during the study. ConclusionN.karma with MVO had better improvement. No adverse event was noticed during the study. N.karma with these oils is effective and safe for migraine.

Online monitoring of oil film thickness of journal bearing in aviation fuel gear pump

As the key support of aviation fuel pumps, journal bearings are operated under extreme conditions of high temperature, high pressure and low viscosity media, therefore, the broken of the ultra-thin lubrication film is the main cause of lubrication failure and abnormal wear. However, the dynamic hydraulic lubrication (DHL) film is still blind due to the lack of non-destructive online monitoring techniques. This paper presents the study of ultrasonic-based measurement for the dynamic oil film thickness of fuel pump. The circumferential oil film thicknesses in a journal bearing are measured with the complex model and the resonance model, meanwhile, the minimum oil film thickness is extracted by fitting the measured points with the initial circle. Under varying operating conditions, the measured results are verified with classical DHL simulations, and the maximum relative error is shown to be lower than 15%.

P-094 Fundamental understanding of sperm motion in viscoelastic media

Abstract Study question How does viscosity influence the flagellar beating behaviour of free-swimming bull, mouse, and human sperm? Summary answer Sperm flagellar beating behaviour exhibits a transition from an irregular three-dimensional (3D) beating at 5 mPa·s to an organized two-dimensional (2D) waveform at 20 mPa·s. What is known already Sperm migrate in a complex viscoelastic environment through the female reproductive tract. The viscoelastic properties of the oviductal fluid significantly influence the progressive motility of sperm, acting as one of the key guidance mechanisms in vivo. However, the biomechanics of sperm flagellar activity in response to varying viscosity of the oviductal fluid is poorly understood. Understanding sperm flagellar behaviour in physiologically relevant environments is crucial to understanding reproduction and may help to describe unknown causes of infertility. Lack of high-speed high-resolution imaging techniques and automated image-analysis capabilities have been the main barriers to fully describe the flagellar beating behaviour. Study design, size, duration We used a custom-built high-speed high-resolution dark-field microscopy platform to resolve the flagellar dynamics of human, bull, and mouse sperm near surfaces in viscoelastic media ranging in viscosity from 1 to 250 mPa·s. The imaging system includes an automated image analysis algorithm to quantify sperm flagellar waveform and motility characteristics by extracting the flagellar centreline, reconstructing the waveform and calculating tangent-angle profiles. 20 sperm from 3 different bull, mice and humans were analyzed. Participants/materials, setting, methods Bull, mouse, and human sperm were used in this study. In each experiment, a diluted sperm sample in a buffer supplemented with methylcellulose was used and free-swimming sperm were imaged using dark-field microscopy at 200 frames per second. An automated image analysis algorithm was used to extract sperm flagellar centreline and Proper Orthogonal Decomposition (POD) was then used to study sperm flagellar waveform. Statistical analysis was performed using one-way ANOVA. Main results and the role of chance The reconstructed flagellar beating pattern was different for sperm swimming in low and high-viscosity media. Bull sperm exhibited a lower flagellar beating amplitude along the end piece when swimming in a high-viscosity media, a potential energy-efficient strategy to navigate a high viscosity fluid. The first two dominant POD modes (shape modes) describe more than 90% of the beating pattern for all species. Bull sperm exhibited a transition mode with irregular loops in 5 mPa·s buffer, but the flagellar shape cycle created an organised repetitive circular cycle in 1 mPa.s (3D beating) buffer and at viscosities higher than 5 mPa·s (2D beating). Human sperm also indicated a similar behaviour but with the transition happening at higher viscosities. Mouse sperm in high-viscosity media had a lower flagellar beating amplitude across the principal piece and higher beating amplitude across the end piece. The flagellar shape cycle in mouse sperm showed a periodic flagellar beating behaviour at high-viscosities (>20 mPa·s), but a shape cycle with distorted loops at lower viscosities. Our results showed in quantitative detail that increasing viscosity alters sperm flagellar beating pattern, and how sperm migration behaviour in low viscosity media can be distinct from their swimming behaviour in vivo. Limitations, reasons for caution A more comprehensive study of sperm motility parameters such as curvilinear velocity, average path velocity and straight line velocity with a larger sample size is required to fully characterise sperm swimming behaviour as a function of viscosity. Wider implications of the findings The increasing viscosity of the oviductal fluid regulates the sperm flagellar beating behaviour to switch from a 3D swimming behaviour with irregular shape cycles at lower viscosities to a 2D slithering mode with repetitive circular shape cycles at higher viscosities to achieve a more energy-efficient beating pattern for navigation. Trial registration number Not applicable

Investigation on the stability and anti-eccentric load margin of a novel structure bearing lubricated by low viscosity medium

Investigation on the stability and anti-eccentric load margin of a novel structure bearing lubricated by low viscosity medium

Dispersing swimming microalgae in self-assembled nanocellulose suspension: Unveiling living colloid dynamics in cholesteric liquid crystals

Active matter comprises individual energy-consuming components that convert locally stored energy into mechanical motion. Among these, liquid crystal dispersed self-propelled colloids have displayed fascinating dynamic effects and nonequilibrium behaviors. In this work, we introduce a new type of active soft matter based on swimming microalgae and lyotropic nanocellulose liquid crystal. Cellulose is a kind of biocompatible polysaccharide that nontoxic to living biological colloids. In contrast to microalgae locomotion in isotropic and low viscosity media, we demonstrate that the propulsion force of swimming microalgae can overcome the stabilizing elastic force in cholesteric nanocellulose liquid crystal, with the displacement dynamics (gait, direction, frequency, and speed) be altered by the surrounding medium. Simultaneously, the active stress and shear flow exerted by swimming microalgae can introduce local perturbation in surrounding liquid crystal orientation order. The latter effect yields hydrodynamic fluctuations in bulk phase as well as layer undulations, helicoidal axis splay deformation and director bending in the cholesteric assembly, which finally followed by a recovery according to the inherent viscoelasticity of liquid crystal matrix. Our results point to an unorthodox design concept to generate a new type of hybrid soft matter that combines nontoxic cholesteric liquid crystal and active particles, which are expected to open opportunities in biosensing and biomechanical applications.

An in vivo assay to study locomotion in Caenorhabditis elegans

Adaptation in the sensory-mechanical loop during locomotion is a powerful mechanism that allows organisms to survive in different conditions and environments. Motile animals need to alter motion patterns in different environments. For example, crocodiles and other animals can walk on solid ground but switch to swimming in water beds. The nematode Caenorhabditis elegans also shows adaptability by employing thrashing behaviour in low viscosity media and crawling in high viscosity media. The mechanism that enables this adaptability is an active area of research. It has been attributed previously to neuro-modulation by dopamine and serotonin. This study introduces an experimental assay to physiologically investigate the neuronal mechanisms of modulation of locomotion by dopamine. The technique is utilized to test gait switching while imaging the mechanosensory dopaminergic neurons PDE. Results revealed their role to be not limited to touch sensation, but to sensing surrounding environment resistance as well. The significance of such characterization is improving our understanding of dopamine gait switching which gets impaired in Parkinson's disease.-A locomotion pattern switching system was devised to allow studying this process in vivo in the nematode C. elegans.-This system allowed the study of dopaminergic neurons PDE response as the worms switched from crawling to swimming.

Electrical Properties and Strain Sensing Mechanisms in Hybrid Graphene Nanoplatelet/Carbon Nanotube Nanocomposites.

Electrical and electromechanical properties of hybrid graphene nanoplatelet (GNP)/carbon nanotube (CNT)-reinforced composites were analyzed under two different sonication conditions. The electrical conductivity increases with increasing nanofiller content, while the optimum sonication time decreases in a low viscosity media. Therefore, for samples with a higher concentration of GNPs, an increase of sonication time of the hybrid GNP/CNT mixture generally leads to an enhancement of the electrical conductivity, up to values of 3 S/m. This means that the optimum sonication process to achieve the best performances is reached in the longest times. Strain sensing tests show a higher prevalence of GNPs at samples with a high GNP/CNT ratio, reaching gauge factors of around 10, with an exponential behavior of electrical resistance with applied strain, whereas samples with lower GNP/CNT ratio have a more linear response owing to a higher prevalence of CNT tunneling transport mechanisms, with gauge factors of around 3–4.

Facile mitochondria localized fluorescent probe for viscosity detection in living cells

Fluorescent probes act as a powerful tool to understand the function of intracellular viscosity, which are closely associated with many functional disorders and diseases. Herein we report a boron-dipyrromethene (4,4-difluoro-4-borata-3a,4a-diaza-s-indacene, BODIPY) group based new fluorescent probe (BV-1), which was synthesized facilely by a one-step Knoevenagel-type condensation reaction, to detect viscosity in living cells with high selectivity and sensitivity. DFT calculation demonstrated that the unsaturated moiety at the meso-position of BODIPY suppressed the fluorescence via twisted intramolecular charge transfer (TICT) mechanism in low viscosity media. By restricting the rotation of the molecular rotor, the fluorescence would be enhanced significantly with redshift in emission wavelength in high viscosity conditions. The fluorescence intensity ratio (log (I/I0)) at 570 nm showed a good linearity (R2 = 0.991) with the viscosity (log η) in the range of 2–868 cP. And the limit of detection (LOD) and limit of quantification (LOQ) for viscosity were calculated to be 0.16 cP and 0.54 cP, respectively. BV-1 was demonstrated to be mitochondria localized with low cytotoxicity. Utilizing the new probe BV-1, the changes in mitochondrial viscosity caused by monensin or nystatin have been monitored successfully in real time. This work will provide new efficient ways for the development of viscosity probes, which are expected to be used for the study of intracellular viscosity properties and functions.

Design, synthesis and application of a dual-functional fluorescent probe for reactive oxygen species and viscosity.

A fluorescence probe based on cyanine fluorophore was designed and synthesized in this work, which can be used to determine viscosity and reactive oxygen species (e.g., OCl-, ONOO-) at different wavelengths. Under a low viscosity medium, the fluorescence quantum yield of the probe is very low; however, with the increase of the medium viscosity, the probe's emission at 571nm is enhanced by nearly 25-fold due to the inhibition of intramolecular rotations. On the other hand, the probe shows a rapid and linear fluorescence response at 710nm to OCl- or ONOO- within 1min. The different spectral response regions of the probe permit the selective detection of both viscosity and reactive oxygen species. Furthermore, the probe is demonstrated to be cell permeable and capable of detecting the viscosity and the total amount of OCl-/ONOO- in living cells with the help of confocal microscope fluorescence imaging.

A simple benzothiazole-based mitochondrial-targeting fluorescent probe for visualizing and monitoring viscosity in living cell, lung organ tissue, and living mice

The irregular cellular viscosity is associated with disease and malfunction at the cellular level, developing simple but effective fluorescence probe for detection of intracellular viscosity is of great significance. Herein, we report a benzothiazole-based fluorescent probe HBTD-V for sensitive response to viscosity change in biological systems. HBTD-V displays weak emission in low-viscosity media but strong fluorescence in high-viscosity media. Linear fitting of the viscosity titration results provided a good linear relationship between the fluorescence intensity (logI583) and viscosity (logη) within the viscosity range of 13.8–221.5 cp, indicating the capability of the probe for quantitative viscosity detection. Probe HBTD-V also holds some advantages such as excellent photostability, good anti-interference ability, and good mitochondrial targeting ability. Moreover, probe HBTD-V has been successfully employed to image the viscosity variations in living MCF-7 cells, mice lung organ and tissues, as well as in living mice body. The results demonstrate that HBTD-V can serve as a sensitive fluorescence probe for investigating the vital role of viscosity changes in complex biological systems.

Magnetically induced heating by iron oxide nanoparticles dispersed in liquids of different viscosities

The AC magnetically induced heating characteristics of uncoated and silica-coated magnetic iron oxide nanoparticles dispersed in liquids of different viscosities were investigated. The aim was to synthesize and prepare uncoated and silica-coated nanoparticles of maghemite, and evaluate their ability to hyperthermically dissipate heat under an applied AC magnetic field when they are dispersed in liquids of different viscosities. A conceptual approach on the relative contributions of the Néel and the Brownian relaxation mechanisms to the hyperthermic heating of these suspensions is proposed. The microstructure, the physical and chemical properties of the uncoated and silica-coated nanoparticles were assessed by transmission electron microscopy; powder X-ray diffraction; 57Fe Mössbauer spectroscopy; Fourier transform infrared spectroscopy; zeta potential measurements; and conventional chemical analysis. Results of the Rietveld refinement of the XRD patterns and analysis of the collected Mössbauer data are well consistent with maghemite as being the only iron oxide phase. The mean diameters of the uncoated nanoparticles increased from ~6 to 7 nm, to 35 and 78 nm, for added silica coating amounts varying from 1 to 6-fold, respectively. Zeta potential measurements confirmed the efficiency of the nanoparticles sol-gel coating method. When dispersed in low viscosity media (water, triethanolamine, ethylene glycol), uncoated nanoparticles efficiently release heat via both Néel and Brown relaxation mechanisms under an applied oscillating magnetic field, achieving a temperature raise of approximately 21 °C. The silica layers tend to inhibit the Brownian motion of coated particles, making heat dissipation to be preferentially governed by the Néel relaxation of the magnetization vector. This leads to modest rises in temperature of 9 °C when they are dispersed in water or in the PVC (polyvinyl chloride). SAR tests indicate that the maghemite-silica core-shell systems might be useful for advanced technologies in medical practices based on local hyperthermia, particularly in oncology.

Experimental investigation on the effects of aqueous solution in electric discharge machining

The aqueous solution of organic compound plays a crucial role as a dielectric medium in Die sink electrical discharge machining process. Two-phase of the dielectric medium, deionised water and aqueous solution of deionised water and glycerin, used in EDM. It eliminates hazards problem. The machining efficiency increases with the concentration of an organic compound in the aqueous solution at long pulse and discharges current compared to the deionised water. The working dielectric medium consists of deionised water and an aqueous solution of deionised water and glycerin. A constant gap voltage used to prove a constant spark gap in the dielectric medium. The drawback rough surface and relative high wear rate are considered at high discharge current in a straight polarity working condition. A regression equation and mathematical modelling used to optimise the process parameters in the investigation. This also reveals the dielectric medium with high viscosity has better machining performance that low viscosity medium.

Characterization of the Hydrodynamics in the USP Basket Apparatus Using Computational Fluid Dynamics

Computational fluid dynamics (CFD) has been extensively used for the USP paddle apparatus II, but limited CFD studies have been conducted on the USP basket apparatus I. We expanded on past CFD basket studies to consider the presence of a tablet inside the basket, compared predictions to in vivo conditions, and confirmed observations around the complexity of nonuniform hydrodynamics. Tablets near the basket perimeter experienced near 5-fold increase in maximum velocity and surface shear stress compared to tablets placed at the center of the basket. At higher basket speeds, the predicted velocities at the center of the basket were closer to in vivo predictions but the surface shear stress was about 2 orders of magnitude lesser. Simulations with a high viscosity fluid (1 Pa-s) showed a 10-fold increase in shear stress on a tablet but a decrease in strain rate compared to low-viscosity medium (0.001 Pa-s) which could impact dissolution rates. Also presented are the insights into turbulent energy dissipation rates that could help in a priori prediction of dissolution rates. Overall, the CFD analysis presented in this work reveals significant differences between the basket and in vivo conditions and will help inform relevant in vitro testing.

Solid-solution fibrous dosage forms for immediate delivery of sparingly-soluble drugs: Part 2. 3D-micro-patterned dosage forms

In part 1, we have investigated drug release by solid-solution single fibers comprising a sparingly water-soluble drug (ibuprofen) and a highly water-soluble dual excipient (low-molecular-weight hydroxypropyl methyl cellulose (HPMC) and polyoxyl stearate (POS)). In this part, fibrous dosage forms of the same formulation are prepared by 3D-micro-patterning, tested, and modeled. Upon immersion in a small volume of dissolution fluid, the dosage forms rapidly swelled and formed a low-viscosity medium, which subsequently dissolved. The dissolution time increased slightly with volume fraction of the fibers, φs, in the solid dosage form, but was less than 25 minutes even up to φs = 0.65. After dosage form dissolution, the fluid was supersaturated by a factor of two; the drug concentration then gradually decreased to solubility. The solubility was proportional to the concentration of POS, and was enhanced by a factor of six at φs = 0.65 (the most densely-packed dosage form). Theoretical models suggest that the dissolution fluid percolates the contiguous void space almost immediately, and the HPMC-POS fibers expand isotropically as water diffuses in. Because the void space remains contiguous in isotropic expansion, the dissolution fluid continues to percolate through and diffuse into the fibers. Thus, even the densely-packed dosage forms form a low-viscosity medium that deforms and dissolves rapidly. Consequently, the solid-solution fibrous dosage forms enable enhanced release rate, supersaturation, and solubility of sparingly-soluble drugs.

Fermentation of Rice Flour Supernatant Using Lactobacillus Paracasei Cba L74

The concept of functional food has evolved throughout the years. These days we define a food to be functional when it confers a benefit to human health. Lactic acid fermentation is one of the most important and used food processing technologies to produce this type of food. Fermentation of Lactobacillus Paracasei CBA L74 - a homofermentative, gram positive probiotic - on rice flour suspension has been proved to be a successful route to produce functional foods. However, the process was characterized by high energy consumption, low air sparging and complex expensive metabolite separation.A research program has been developed to carry out L. Paracasei fermentation using a low viscosity medium based on rice flour suspension. Fractionation of rice flour suspension provided a medium characterized by low amounts of solids and nutrients at concentration high that support the microorganism growth. Fermentations were carried in a 1L batch reactor equipped with an agitation systems designed to provide uniform mixing. The composition of the medium; cells, glucose, protein, pH, metabolite production as well as L. Paracasei’ growth trend was analysed throughout the process. Fermentation on supernatant obtained from rice flour and water suspension through centrifugation were possible to produce a potential probiotic functional food with a good bacterial charge.

Rapid sperm capture: high-throughput flagellar waveform analysis.

STUDY QUESTIONCan flagellar analyses be scaled up to provide automated tracking of motile sperm, and does knowledge of the flagellar waveform provide new insight not provided by routine head tracking?SUMMARY ANSWERHigh-throughput flagellar waveform tracking and analysis enable measurement of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses, which are not possible by tracking the sperm head alone.WHAT IS KNOWN ALREADYThe clinical gold standard for sperm motility analysis comprises a manual analysis by a trained professional, with existing automated sperm diagnostics [computer-aided sperm analysis (CASA)] relying on tracking the sperm head and extrapolating measures. It is not currently possible with either of these approaches to track the sperm flagellar waveform for large numbers of cells in order to unlock the potential wealth of information enclosed within.STUDY DESIGN, SIZE, DURATIONThe software tool in this manuscript has been developed to enable high-throughput, repeatable, accurate and verifiable analysis of the sperm flagellar beat.PARTICIPANTS/MATERIALS, SETTING, METHODSUsing the software tool [Flagellar Analysis and Sperm Tracking (FAST)] described in this manuscript, we have analysed 176 experimental microscopy videos and have tracked the head and flagellum of 205 progressive cells in diluted semen (DSM), 119 progressive cells in a high-viscosity medium (HVM) and 42 stuck cells in a low-viscosity medium. Unscreened donors were recruited at Birmingham Women’s and Children’s NHS Foundation Trust after giving informed consent.MAIN RESULTS AND THE ROLE OF CHANCEWe describe fully automated tracking and analysis of flagellar movement for large cell numbers. The analysis is demonstrated on freely motile cells in low- and high-viscosity fluids and validated on published data of tethered cells undergoing pharmacological hyperactivation. Direct analysis of the flagellar beat reveals that the CASA measure ‘beat cross frequency’ does not measure beat frequency; attempting to fit a straight line between the two measures gives n}{}{mathrm{R}}^2 values of 0.042 and 0.00054 for cells in DSM and HVM, respectively. A new measurement, track centroid speed, is validated as an accurate differentiator of progressive motility. Coupled with fluid mechanics codes, waveform data enable extraction of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses. We provide a powerful and accessible research tool, enabling connection of the mechanical activity of the sperm to its motility and effect on its environment.LARGE SCALE DATAThe FAST software package and all documentation can be downloaded from www.flagellarCapture.com.LIMITATIONS, REASONS FOR CAUTIONThe FAST software package has only been tested for use with negative phase contrast microscopy. Other imaging modalities, with bright cells on a dark background, have not been tested but may work. FAST is not designed to analyse raw semen; it is specifically for precise analysis of flagellar kinematics, as that is the promising area for computer use. Flagellar capture will always require that cells are at a dilution where their paths do not frequently cross.WIDER IMPLICATIONS OF THE FINDINGSCombining tracked flagella with mathematical modelling has the potential to reveal new mechanistic insight. By providing the capability as a free-to-use software package, we hope that this ability to accurately quantify the flagellar waveform in large populations of motile cells will enable an abundant array of diagnostic, toxicological and therapeutic possibilities, as well as creating new opportunities for assessing and treating male subfertility.STUDY FUNDING/COMPETING INTEREST(S)M.T.G., G.C., J.C.K-B. and D.J.S. gratefully acknowledge funding from the Engineering and Physical Sciences Research Council, Healthcare Technologies Challenge Award (Rapid Sperm Capture EP/N021096/1). J.C.K-B. is funded by a National Institute of Health Research (NIHR) and Health Education England, Senior Clinical Lectureship Grant: The role of the human sperm in healthy live birth (NIHRDH-HCS SCL-2014-05-001). This article presents independent research funded in part by the NIHR and Health Education England. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The data for experimental set (2) were funded through a Wellcome Trust-University of Birmingham Value in People Fellowship Bridging Award (E.H.O.).The authors declare no competing interests.