• Laser surface modification of polymeric materials for microbiological applications

      Gillett, Alice R.; Waugh, David G.; Lawrence, Jonathan; University of Chester (Elsevier, 2016-04-15)
    • Laser Surface Treatment of a Polymeric Biomaterial: Wettability Characteristics and Osteoblast Cell Response Modulation

      Waugh, David G.; Lawrence, Jonathan; University of Chester (Old City Publishing, 2014)
      Biotechnology has the potential to improve people's quality of life and holds the key to-many unmet clinical needs. In the UK alone the biotechnology market is worth £4.5 billion and estimates of future growth ranks from 10 to 15%. This growth can only be driven by the increased use of inexpensive and easy to manufacture polymeric biomaterials. Although polymer science is a rapidly developing area of research, it remains that one of the most intractable problems encountered in biotechnology is that the performance of polymeric biomaterials depends both upon the bulk and surface properties. In this book the authors describe Their work using lasers to modify the wettability characteristics of nylon 6,6 (as wetting often is the primary factor dictating the adhesion and bonding potential of materials) as a route to enhancing the area in terms of in vitro osteoblast cell response. What is more, modifying wettability characteristics in this way is shown to be a highly attractive means of estimating the biofunctionality of a polymer. The book demonstrates and explains how the generation of a biomimetic polymers and is surface using laser beams provides an in vitro platform on which to deposit and grow cells for either the development of implants or to reconstitute functional tissue. The correlative trends and generic characteristics which are identified are in the book between the laser treatment, wettability characteristics and osteoblast cell response of the nylon 6,6 provide a means to estimate the osteoblast cell response in vivo. The book shows clearly that laser surface modification of polymeric materials has tremendous potential for application within the field of regenerative medicine.
    • Laser surface treatment of polyamide and NiTi alloy and the effects on mesenchymal stem cell response

      Waugh, David G.; Lawrence, Jonathan; Shukla, Pratik; Chan, Chi-Wai; Hussain, Issam; Man, Hau-Chung; Smith, Graham C.; University of Chester ; University of Chester ; University of Chester ; Queen's University, Belfast ; University of Lincoln ; Hong Kong Polytechnic University ; University of Chester (2015-03-18)
      Mesenchymal stem cells (MSCs) are known to play important roles in development, post-natal growth, repair, and regeneration of mesenchymal tissues. What is more, surface treatments are widely reported to affect the biomimetic nature of materials. This paper will detail, discuss and compare laser surface treatment of polyamide (Polyamide 6,6), using a 60 W CO2 laser, and NiTi alloy, using a 100 W fiber laser, and the effects of these treatments on mesenchymal stem cell response. The surface morphology and composition of the polyamide and NiTi alloy were studied by scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS), respectively. MSC cell morphology cell counting and viability measurements were done by employing a haemocytometer and MTT colorimetric assay. The success of enhanced adhesion and spreading of the MSCs on each of the laser surface treated samples, when compared to as-received samples, is evidenced in this work.
    • Modifications of surface properties of beta Ti by laser gas diffusion nitriding

      Ng, Chi-Ho; Lawrence, Jonathan; Waugh, David G.; Chan, Chi-Wai; Man, Hau-Chung; University of Chester (Laser Institute of America, 2015-10)
      β -type Ti-alloy is a promising biomedical implant material as it has a low Young’s modulus but is also known to have inferior surface hardness. Various surface treatments can be applied to enhance the surface hardness. Physical vapour deposition (PVD) and chemical vapour deposition (CVD) are two examples of this but these techniques have limitations such as poor interfacial adhesion and high distortion. Laser surface treatment is a relatively new surface modification method to enhance the surface hardness but its application is still not accepted by the industry. The major problem of this process involves surface melting which results in higher surface roughness after the laser surface treatment. This paper will report the results achieved by a 100 W CW fiber laser for laser surface treatment without the surface being melted. Laser processing parameters were carefully selected so that the surface could be treated without surface melting and thus the surface finish of the component could be maintained. The surface and microstructural characteristics of the treated samples were examined using X-ray diffractometry (XRD), optical microscopy (OM), 3-D surface profile & contact angle measurements and nano-indentation test.