BREAST IMPLANT SURFACE DEVELOPMENT

UoM administered thesis: Phd

  • Authors:
  • Anai Valencia Lazcano

Abstract

Bilateral breast augmentation is one of the most common cosmetic surgical procedures carried out on women in the western world. Breast augmentation involves increasing the volume of a woman's breasts through surgery by placing a silicone implant in the subglandular or subpectoral cavity. Although a capsule forms inevitably around breast implants as a natural part of healing, it can cause significant morbidity if the capsule becomes firm and contracted, a condition known as breast capsular contracture (BCC). The aetiology of BCC remains unknown however it is characterised by dense fibrocollagenous connective tissue with a local inflammatory response. Host response is influenced by several factors including implant surface texture, chemistry and interactions between cells and the extracellular matrix. Texturing holds the implant in place, thus preventing micromotion at the host prosthesis interface. While in smooth surfaces, the implant moves inside the breast, making the fibroblasts repeatedly produce collagen in response to this host-prosthesis shearing motion. In this thesis, the effect of surface characteristics and specific coatings on the cell-surface interaction has been examined on smooth compared to textured surfaces using commercially available breast implants.The properties of breast implants shells have been characterised using confocal laser microscopy, contact angle measurements, confocal Raman spectroscopy and tensile testing. Confocal laser microscopy was used to evaluate the topographical features and surface roughness of the implant surfaces. Contact angle measurements were carried out to determine the hydrophobicity of the implant surfaces. Chemical characterisation was carried out recording Raman images and spectra of the implants using confocal Raman spectrometer. The mechanical properties of the breast implant shells were measured via tensile testing. Adhesive interactions of breast-derived fibroblasts with breast implant surfaces were examined in-vitro. For this purpose, the effect of four molecule coatings (aggrecan, collagen I, fibronectin, and hyaluronic acid) was evaluated on fibroblast attachment, proliferation, fibroblast morphology, spreading, cytotoxicity and gene expression.Results from in-vitro assays demonstrated cell susceptibility to topography and protein coatings and further showed cytoskeletal re-organisation and modification with specific cell adhesion patterns. Combination of diverse topographies and specific coatings induced differential regulation of the expression of adhesion related genes, such as focal adhesion kinase, paxillin, vinculin, and alpha-actinin on breast fibroblasts.In conclusion, this thesis has demonstrated the extent and strength of cell adhesion and subsequent cell proliferation and differentiation. This is based on the physical interactions between cells and the extracellular environment in the form of topography and on the chemical interactions mediated by specific coatings. Precise characterisation of the silicone breast implant surfaces was achieved. This may play an important role in the development of improved breast implant surfaces with improved qualities leading the development of surfaces that may be less prone to capsular contracture.

Details

Original languageEnglish
Awarding Institution
Supervisors/Advisors
Award date1 Aug 2015