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Title: Semen quality detection using acoustic wave sensors
Author: Atherton, S.
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 2011
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Artificial insemination (AI) is a widely used part of the modern agricultural industry, with the number of animals inseminated globally being measured in the millions per anum. Crucial to the success of AI is that the sperm sample used is of a high Quality. Two factors which determine the quality of the sample are the number of sperm present and their motility. There are numerous methods used to analyse the quality of a sperm sample, but these are generally laboratory based, expensive and in need of a skilled operator to perform the analysis. It would, therefore be useful to have a simple and inexpensive system which could be used outside the laboratory, immediately prior to the insemination of the animal. Presented in this thesis is work developing a time of flight (ToF) technique which makes use of a quartz crystal microbalance (QCM), operating at 5 MHz, as the sensing element. Data is shown developing a device where a 50 μl sample of boar sperm is added to a liquid filled swim channel, which the sperm are allowed to self-propel down and attach to the surface of a QCM at the end. The attachment of the sperm to the surface causes a measurable frequency decrease in the QCM, aproximately 50 Hz. An average effective mass measurement was made using a QCM and gave a value of 8 ± 5 pg per sperm, which was used in conjunction with the frequency change to determine the number rate of sperm reaching the QCM. Additional data is presented to investigate the effect of environmental temperature on the ToF of the sperm, showing a decrease in ToF between 23 0C to 37 0C. The system was also used to investigate increasing the swim speed of the sperm by chemical means. A range of 20 μmol to 100 μmol of progesterone was added to the swim medium and the ToF was shown to decrease as a result. To further develop the system, large commercial electronics were replaced by smaller circuits built in-house. An oscillator circuit based on a Pierce oscillator was used to drive the QCM and a frequency counter circuit making use of a universal frequency to digital converter (UFDC-1) was used to measure the frequency of the QCM. ToF experiments were performed which showed these pieces of equipment to be effective for performing the analysis of sperm samples. The swim cell itself was also refined, resulting in a compact, modular design. Work was performed developing layer-guided, single-port acoustic resonators to replace the QCM as the sensing element in the sperm analysis device. A maximum mass sensitivity of 1110 Hzμg-1cm-2 was found for devices on a LiTaO3 substrate with a 6 μm guiding layer. While viscosity-density sensing experiments found a maximum sensitivity of 488 KHz Pa-1/2 kg1/2 for a 4 μm guiding layer.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available