University of Exeter funding: Medical Studies - Self funded PhD

Development of novel nitric oxide-releasing polymers for medical devices. Self funded Medical Studies PhD Ref: 3509

About the Research Project


Lead supervisor: Professor Paul Winyard, College of Medicine and Health 

Project description: 
Infections associated with the employment of urinary catheters and intravenous cannulae are a common cause of hospitalisation, illness and premature death (Chant et al 2011). A single episode of cannula-related septicaemia has been estimated, in the USA, to cost in excess of $10,000 (Warren et al, 2006). Thus, the clinical problem that this project addresses is enormous. The cost of catheter- and cannula-related infections is significant not only in health-care related costs, such as prolonged in-patient stay, but also in blocked catheters requiring urgent hospital admission and increased mortality in intensive care units in patients with septicaemia resulting from infected intravenous cannulae. There is increasing clinical research interest in bacterial biofilm formation on implantable medical devices. Such biofilms are often resistant to conventional antibiotics (Hetrick and Schoenfisch 2006), causing serious illness and failure of the device (e.g. catheter blockage).

This project will apply recent developments in our understanding of the antimicrobial role of NO, together with our studies of the capacity of acidified nitrite to release NO (Duncan et al 1995; Zhang et al 1998; Hardwick et al 2001; Lundberg et al 2004; Gilchrist et al 2010). Acidification of nitrite is now known to be an important mechanism by which NO is generated in the gut and skin of mammals to prevent infection. In addition to inhibiting adherence and growth of pathogenic bacteria, NO powerfully inhibits the activation of blood platelets and thereby prevents blood clotting. This property may well be useful in improving the antithrombotic inner surface of polymer arterial grafts which are made from Dacron or PTFE (polytetrafluoroethylene; Teflon).

The aim of the project is to use this method of NO generation to confer antimicrobial activity to medical devices made from, or coated with, polymers. We have already shown that acidified nitrite can be incorporated into a silicone polymer which will release NO when exposed to water. One exciting aspect of this technology is that it can, in theory, be applied to a large number of different polymers and would therefore need little alteration in the production line of existing plastic medical devices such as catheters, cannulae and implantable devices. An ability to manufacture NO-releasing plastics, that are resistant to the growth of microbial biofilms, could provide a revolutionary solution to the ever-increasing and serious issue of infections associated with medical device implantation. The aim of the project will be to establish: (a) that NO-releasing polymers of several types can be manufactured; (b) the optimum NO release to inhibit the growth of bacterial biofilms.

The supervisory team is uniquely placed, in terms of expertise and the availability of facilities - for biophysical testing of NO diffusion through plastics, for in vitro research, e.g. cell culture and ozone-based chemiluminescence for the detection of NO (full facilities in the IBCS St Luke’s laboratories), and clinical facilities at the RD&E, including the NIHR Clinical Research Facility. Suitable Candidates may have backgrounds in Bioscience, Biomedical Science, Biochemistry, Microbiology, Chemistry, Physics, Materials Science, or related subjects.

For more information about the project and informal enquiries, please contact the primary supervisor: 
Professor Paul Winyard

Information about current fees:

Information about possible funding sources:

Information about Doctoral Loans:


     Chant C, Smith OM, Marshall JC, Friedrich JO (2011) Critical Care Med 39, 1167-73.
     Duncan C, Dougal H, Johnston P, Green S, Brogan R, Leifert C, Smith L, Golden M, Benjamin N (1995) Nature Med 1, 546-51.
     Gilchrist M, Winyard PG, Benjamin (2010) Nitric Oxide 22, 104-109.
     Hardwick JBJ, Tucker AT, Wilks M, Johnston A and Benjamin N (2001) Clin Sci 100, 395–400.
     Hetrick EM, Schoenfisch MH (2006) Chem Soc Rev, 35, 780–9.
     Lundberg JO, Weitzberg E, Cole JA, Benjamin N (2004) Nature Rev Microbiol 2, 593-602.
     Warren DK, Quadir WW, Hollenbeak CS, Elward AM, Cox MJ, Fraser VJ (2006) Crit Care Med. 34, 2084-89
     Zhang Z, Naughton D, Winyard PG, Benjamin N, Blake DR, Symons MCR (1998) Biochem Biophys Res Commun 249, 767-72.

Entry requirements

You should have or expect to achieve at least a 2:1 Honours degree from a UK university, or equivalent, in Bioscience, Biomedical Science, Biochemistry, Microbiology, Chemistry, Physics, Materials Science, or related subjects.

If English is not your first language you will need to meet the English language requirements and provide proof of proficiency. Click here for more information and a list of acceptable alternative tests.

How to apply

To apply, please use the 'Apply Now' button above.

You will need to upload the following documents to the application form. Please note our preferred format is PDF, each file named with your surname and the name of the document, eg. “Smith – CV.pdf”, “Smith – Cover Letter.pdf”, “Smith – Transcript.pdf”:

  • CV
  • Letter of application outlining your academic interests, prior research experience. You should also indicate your reasons for wishing to undertake the project.
  • Transcript(s) giving full details of subjects studied and grades/marks obtained. This should be an interim transcript if you are still studying.
  • Two references (see Reference information section below)
  • If you are not a national of a majority English-speaking country you will need to submit evidence of your current proficiency in English.  For further details of the University’s English language requirements please see

Reference information

If possible, please upload your references to the online application form. If your referees would prefer to send their reference directly to the University, please ask them to send these via email to

References should be in the form of a letter. Referees must email their references to us from their institutional email accounts. We cannot accept references from personal/private email accounts, unless it is a scanned document on institutional headed paper and signed by the referee.

All application documents must be submitted in English. Certified translated copies of academic qualifications must also be provided.

The closing date for applications is midnight (GMT) on 27 January 2020


Application deadline:27th January 2020
Value:This project is self funded
Duration of award:Not applicable
Contact: PGR Enquiries