WHO laboratory manual for the examination and processing of human semen. Sixth Edition

World Health Organisation, J. C. Kirkman-Brown, M. T. Gallagher et al. 2021

The World Health Organisation has launched the 6th Edition laboratory manual for the examination and processing of human semen. Jackson served on the Editorial Board, while Meurig helped write the sperm motility and CASA sections. The manual provides an excellent resource to help scientists, technicians, laboratory experts and healthcare workers worldwide ensure high quality testing of human semen. We are particularly excited that FAST, and flagellar capture more generally, was highlighted as an emerging technology for the future!

Heads and Tails: Requirements for Informative and Robust Computational Measures of Sperm Motility

G. Cupples, M. T. Gallagher, D. J. Smith, J. C. Kirkman-Brown 2021

In this chapter we discussed the potential that computational analysis of sperm motility has for assessing male fertility. We highlight that for this potential to be realised, it is essential that computerised assessments are conducted with the same level of rigour as manual analyses, and how this should be done. Preparation, Imaging, Data Analysis and Mechanics all matter when it comes to trying to reliably and reproducibly assess samples.

Doing more with less: The flagellar end piece enhances the propulsive effectiveness of human spermatozoa

C. V. Neal, A. L. Hall-McNair, J. C. Kirkman-Brown, D. J. Smith, M. T. Gallagher 2020

In this work we showed that the inactive end piece of the tail plays a big role in how quickly and how efficiently sperm swim. Instead of actively bending, the end piece passively relaxes, resulting in faster, more efficient swimming. This effect ranges from a few percent to as large as a 430% increase when compared to a fully active tail. This finding was highlighted in NewScientist and BNR.

Rapid sperm capture: high-throughput flagellar waveform analysis

M. T. Gallagher, G. Cupples, J. C. Kirkman-Brown, D. J. Smith 2019

In this paper we present for the first time the results of analysis using FAST. We demonstrate the FAST capability on hundreds of motile human sperm swimming in both diluted semen and high-viscosity media. 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.

CASA: tracking the past and plotting the future

M. T. Gallagher, D. J. Smith, J. C. Kirkman-Brown 2018

In this review paper we explore the past and present of Computer Aided Sperm Analysis (CASA), discuss clinical uses and potential areas for clinical translation of existing research technologies. In particular we look ahead to the future of computer analysis and potential to revolutionise the science of male fertility, laying out the potential for automated flagellar tracking such as that provided by FAST.

Meshfree and efficient modeling of swimming cells

M. T. Gallagher, D. J. Smith 2018

In this modelling paper we show how the NEAREST code package enables easy and accurate simulation of flagellar motility. Using the NEAREST package we are able to calculate the disturbance to flow around swimming cells, enabling visualisation of the impact a sperm has on its environment without need for complicated experimental protocols, which can be expensive and, on these scales, significantly affected by noise.

The mechanics of hyperactivation in adhered human sperm

E. H. Ooi, D. J. Smith, H. Gadêlha, E. A. Gaffney, J. C. Kirkman-Brown 2014

In this paper we developed an experimental system to reveal the response of individual cells to pharmacological motility stimulus. The system consists of adhering sperm to a surface and imaging flagellar motion before and after perfusion with a compound (in this case the potassium channel modulator 4-aminopyridine). Mathematically analysing the flagellar waveform and combining this data with fluid dynamic modelling then enables the estimation of forces and energy dissipation. A surprising finding was that cells may actually dissipate less energy during hyperactivation than prior to induction of hyperactivation.

Sperm motility: is viscosity fundamental to progress?

J. C. Kirkman-Brown, D. J. Smith 2011

In this review paper we tackle the question of viscosity, and whether it is essential for successful internal fertilisation. Viscous effects play many roles in the migration of sperm through the female tract, be it allowing entrance into the cervix, preventing entrance through use of the female contraceptive pill, or having a significant impact in controlling the migrating sperm and their flagellar waveforms.

Bend propagation in the flagella of migrating human sperm, and its modulation by viscosity

D. J. Smith, E. A. Gaffney, H. Gadâlha, N. Kapur, J. C. Kirkman-Brown 2009

Successfully migrating human sperm are able to push their way through fluids that are over 200 times the viscosity of saline, without significantly slowing down. In this experimental paper we perform high frame rate imaging on the flagellum of human sperm in high viscosity fluidic environments, characterising in detail the development and propagation of the waveform, and its remarkable adaptation to the challenge presented by the surrounding viscous fluid.