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Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells / Yuan He

DOI (Published version): 10.23889/Suthesis.43734

Abstract

Atomic force microscopy (AFM) is an important measurement methodology for the study of interactions at the micro and nanoscale. The study of colloidal interactions at microbial cell or membrane surfaces can be significantly extended by the application of AFM imaging and force measurement capabilitie...

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Published: 2018
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa43734
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fullrecord <?xml version="1.0"?><rfc1807><datestamp>2018-09-14T12:00:31.6425306</datestamp><bib-version>v2</bib-version><id>43734</id><entry>2018-09-07</entry><title>Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces &#x2013; Membranes and Cells</title><swanseaauthors/><date>2018-09-07</date><abstract>Atomic force microscopy (AFM) is an important measurement methodology for the study of interactions at the micro and nanoscale. The study of colloidal interactions at microbial cell or membrane surfaces can be significantly extended by the application of AFM imaging and force measurement capabilities to provide unique insights into the surface properties and their relationships. The zeta-potential of membrane and cell surfaces can be mathematically described with Boris Derjaguin, Lev Landau, Evert Verwey and Theodoor Overbeek (DLVO) theories and linked to surface interactions. The research of this thesis analyses AFM force-distance measurements and has developed a FORTRAN program to calculate surface properties from AFM force spectroscopy. In the first instance the developed AFM measurement platform allowed the determination of zeta-potential at the nanoscale across a membrane surface (DK). The mapping of the zeta-potential across a surface within a process relevant environment alongside the measurement of other surface properties is unique to AFM and the presented thesis.The distribution of zeta-potential across the membrane or microbial surfaces was found to be as large as &#xB1;20mV with the average zeta potential ranging from 10mV to a maximum as 35mV depending on the surface and aqueous environment. The results were compared to other zeta potential measuring methods; zeta-sizer for cells and streaming potential for DK membrane surface. Zeta potential mapping across the surfaces could also be achieved with the AFM method.The surface adhesion is a prominent feature of force curves and the research of the thesis extended the FORTRAN program for numerical analysis of the force curve. Maximum adhesion could be measured as more than 10000pN, while minimum could be less than 100pN. Hydrophobicity of cells was also measured to aid interpretation of AFM data. With a combination of reaction equilibrium and Gaussian distribution, the research demonstrates that the method can identify the type of functional groups on the sample surface.To illustrate the application of the developed AFM analysis the influence of chemical additives on the surface interactions was also investigated. The effect of Sodium tripolyphosphate (STP) on zeta potential at bacterial and yeast cell surfaces was studied. The effect of STP was to narrow the distribution of zeta potential from 10 &#x2013; 20mV to 10 &#x2013; 15mV for both yeasts and bacteria. The influence of the antibiotic amoxicillin was also examined and there was a significant adhesion detected with the non-amoxicillin treated cells; maximum of about 3000pN for NCYC-1324 and maximum of around 30000pN for NCYC-1681. The adhesion was reduced to a few hundred pN within 15mins in low amoxicillin (0.1mg/l). A longer time of exposure or higher concentration caused damage to the cell and reduced the validity of the cell adhesion measurement.In conclusion, the work of the thesis has developed an AFM analysis platform that allows the novel interrogation of AFM force-distance curves measured across surfaces. This provides unique insight into the interactions found at the surface which govern the behaviour of colloids and bio-colloids and impacts within medicine, bioprocess engineering and the natural environment.</abstract><type>E-Thesis</type><journal/><publisher/><keywords>Yeast, Membrane, AFM, Colloid</keywords><publishedDay>31</publishedDay><publishedMonth>12</publishedMonth><publishedYear>2018</publishedYear><publishedDate>2018-12-31</publishedDate><doi>10.23889/Suthesis.43734</doi><url/><notes>A selection of third party content is redacted or is partially redacted from this thesis.</notes><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><apcterm/><lastEdited>2018-09-14T12:00:31.6425306</lastEdited><Created>2018-09-07T14:30:47.9370754</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Uncategorised</level></path><authors><author><firstname>Yuan</firstname><surname>He</surname><order>1</order></author></authors><documents><document><filename>0043734-07092018145402.pdf</filename><originalFilename>He_Yuan_PhD_Final_Thesis_Redacted.pdf</originalFilename><uploaded>2018-09-07T14:54:02.9370000</uploaded><type>Output</type><contentLength>4727757</contentLength><contentType>application/pdf</contentType><version>Redacted version - open access</version><cronfaStatus>true</cronfaStatus><embargoDate>2018-09-07T00:00:00.0000000</embargoDate><copyrightCorrect>true</copyrightCorrect></document></documents><OutputDurs/></rfc1807>
spelling 2018-09-14T12:00:31.6425306 v2 43734 2018-09-07 Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells 2018-09-07 Atomic force microscopy (AFM) is an important measurement methodology for the study of interactions at the micro and nanoscale. The study of colloidal interactions at microbial cell or membrane surfaces can be significantly extended by the application of AFM imaging and force measurement capabilities to provide unique insights into the surface properties and their relationships. The zeta-potential of membrane and cell surfaces can be mathematically described with Boris Derjaguin, Lev Landau, Evert Verwey and Theodoor Overbeek (DLVO) theories and linked to surface interactions. The research of this thesis analyses AFM force-distance measurements and has developed a FORTRAN program to calculate surface properties from AFM force spectroscopy. In the first instance the developed AFM measurement platform allowed the determination of zeta-potential at the nanoscale across a membrane surface (DK). The mapping of the zeta-potential across a surface within a process relevant environment alongside the measurement of other surface properties is unique to AFM and the presented thesis.The distribution of zeta-potential across the membrane or microbial surfaces was found to be as large as ±20mV with the average zeta potential ranging from 10mV to a maximum as 35mV depending on the surface and aqueous environment. The results were compared to other zeta potential measuring methods; zeta-sizer for cells and streaming potential for DK membrane surface. Zeta potential mapping across the surfaces could also be achieved with the AFM method.The surface adhesion is a prominent feature of force curves and the research of the thesis extended the FORTRAN program for numerical analysis of the force curve. Maximum adhesion could be measured as more than 10000pN, while minimum could be less than 100pN. Hydrophobicity of cells was also measured to aid interpretation of AFM data. With a combination of reaction equilibrium and Gaussian distribution, the research demonstrates that the method can identify the type of functional groups on the sample surface.To illustrate the application of the developed AFM analysis the influence of chemical additives on the surface interactions was also investigated. The effect of Sodium tripolyphosphate (STP) on zeta potential at bacterial and yeast cell surfaces was studied. The effect of STP was to narrow the distribution of zeta potential from 10 – 20mV to 10 – 15mV for both yeasts and bacteria. The influence of the antibiotic amoxicillin was also examined and there was a significant adhesion detected with the non-amoxicillin treated cells; maximum of about 3000pN for NCYC-1324 and maximum of around 30000pN for NCYC-1681. The adhesion was reduced to a few hundred pN within 15mins in low amoxicillin (0.1mg/l). A longer time of exposure or higher concentration caused damage to the cell and reduced the validity of the cell adhesion measurement.In conclusion, the work of the thesis has developed an AFM analysis platform that allows the novel interrogation of AFM force-distance curves measured across surfaces. This provides unique insight into the interactions found at the surface which govern the behaviour of colloids and bio-colloids and impacts within medicine, bioprocess engineering and the natural environment. E-Thesis Yeast, Membrane, AFM, Colloid 31 12 2018 2018-12-31 10.23889/Suthesis.43734 A selection of third party content is redacted or is partially redacted from this thesis. COLLEGE NANME COLLEGE CODE Swansea University Doctoral Ph.D 2018-09-14T12:00:31.6425306 2018-09-07T14:30:47.9370754 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised Yuan He 1 0043734-07092018145402.pdf He_Yuan_PhD_Final_Thesis_Redacted.pdf 2018-09-07T14:54:02.9370000 Output 4727757 application/pdf Redacted version - open access true 2018-09-07T00:00:00.0000000 true
title Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells
spellingShingle Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells
,
title_short Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells
title_full Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells
title_fullStr Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells
title_full_unstemmed Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells
title_sort Atomic Force Microscopy Study of the Interactions Between Colloids and Surfaces – Membranes and Cells
author ,
author2 Yuan He
format E-Thesis
publishDate 2018
institution Swansea University
doi_str_mv 10.23889/Suthesis.43734
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
document_store_str 1
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description Atomic force microscopy (AFM) is an important measurement methodology for the study of interactions at the micro and nanoscale. The study of colloidal interactions at microbial cell or membrane surfaces can be significantly extended by the application of AFM imaging and force measurement capabilities to provide unique insights into the surface properties and their relationships. The zeta-potential of membrane and cell surfaces can be mathematically described with Boris Derjaguin, Lev Landau, Evert Verwey and Theodoor Overbeek (DLVO) theories and linked to surface interactions. The research of this thesis analyses AFM force-distance measurements and has developed a FORTRAN program to calculate surface properties from AFM force spectroscopy. In the first instance the developed AFM measurement platform allowed the determination of zeta-potential at the nanoscale across a membrane surface (DK). The mapping of the zeta-potential across a surface within a process relevant environment alongside the measurement of other surface properties is unique to AFM and the presented thesis.The distribution of zeta-potential across the membrane or microbial surfaces was found to be as large as ±20mV with the average zeta potential ranging from 10mV to a maximum as 35mV depending on the surface and aqueous environment. The results were compared to other zeta potential measuring methods; zeta-sizer for cells and streaming potential for DK membrane surface. Zeta potential mapping across the surfaces could also be achieved with the AFM method.The surface adhesion is a prominent feature of force curves and the research of the thesis extended the FORTRAN program for numerical analysis of the force curve. Maximum adhesion could be measured as more than 10000pN, while minimum could be less than 100pN. Hydrophobicity of cells was also measured to aid interpretation of AFM data. With a combination of reaction equilibrium and Gaussian distribution, the research demonstrates that the method can identify the type of functional groups on the sample surface.To illustrate the application of the developed AFM analysis the influence of chemical additives on the surface interactions was also investigated. The effect of Sodium tripolyphosphate (STP) on zeta potential at bacterial and yeast cell surfaces was studied. The effect of STP was to narrow the distribution of zeta potential from 10 – 20mV to 10 – 15mV for both yeasts and bacteria. The influence of the antibiotic amoxicillin was also examined and there was a significant adhesion detected with the non-amoxicillin treated cells; maximum of about 3000pN for NCYC-1324 and maximum of around 30000pN for NCYC-1681. The adhesion was reduced to a few hundred pN within 15mins in low amoxicillin (0.1mg/l). A longer time of exposure or higher concentration caused damage to the cell and reduced the validity of the cell adhesion measurement.In conclusion, the work of the thesis has developed an AFM analysis platform that allows the novel interrogation of AFM force-distance curves measured across surfaces. This provides unique insight into the interactions found at the surface which govern the behaviour of colloids and bio-colloids and impacts within medicine, bioprocess engineering and the natural environment.
published_date 2018-12-31T03:55:04Z
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