An Impact of Different Silicone Breast Implants on the Bacterial Attachment and Growth

Bacterial biofilms have been implicated with breast implant complications including capsular contracture, double-capsule formation, and breast implant-associated anaplastic large cell lymphoma. However, the relationship between implant surface texture and microbial biofilm formation is insufficiently evaluated. In the present study, we examined the antimicrobial activities of different types of silicone breast implant. The growth of bacterial including Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa was compared using implants with various surface textures, including Hans Smooth, Hans SmoothFine, Allergan Smooth, Eurosilicone Smooth, Eurosilicone Texture, Sebbin Smooth, Sebbin Micro, Sebbin Texture, and Motiva Smooth. Microbial investigation revealed the increased growth of S. aureus on breast implants after 48 h, except Eurosilicone Smooth, Eurosilicone Texture, Hans SmoothFine and Sebbin Smooth material. At 48 hours, there was no major difference between the S. aureus attachment on smooth and textured implants. The results of S. epidermis attachment on the implant after 48 h showed that their growth decreased on surfaces of Motiva Smooth, Sebbin Smooth, and Eurosilicone Smooth. These results indicated that S. epidermis was unable to survive on these breast implants. Eventually, P. aeruginosa count had showed decrease of bacterial count after 48 hours compared to 24 hours in most of the implants except for Eurosilicone Texture, Sebbin Smooth and Sebbin Micro, where the count of P. aeruginosa slightly increased. This indicated that P. aeruginosa was unable to exist on the smooth surfaces. Our results show that the in vitro assay revealed no significant difference between smooth and textured surfaces and showed variable interactions and needed further molecular analysis to assess their adherence nature.

Modelling the combined effect of surface roughness and topography on bacterial attachment

Bacterial attachment is a complex process affected by flow conditions,imparted stresses,and the surface properties and structure of both the supporting material and the cell.Experiments on the initial attachment of cells of the bacterium Streptococcus gordonii(S.gordonii),an important early coloniser of dental plaque,to samples of stainless steel(SS)have been reported in this work.The primary aim motivating this study was to establish what affect,if any,the surface roughness and topology of samples of SS would have on the initial attachment of cells of the bacterium S.gordonii.This material and bacterium were chosen by virtue of their relevance to dental implants and dental implant infections.Prior to bacterial attachment,surfaces become conditioned by the interfacing environment(salivary pellicle from the oral cavity for instance).For this reason,cell attachment to samples of SS pre-coated with saliva was also studied.By implementing the Extended Derjaguin Landau Verwey and Overbeek(XDLVO)theory coupled with convection-diffusion-reaction equations and the surface roughness information,a computational model was developed to help better understand the physics of cell adhesion.Surface roughness was modelled by reconstructing the surface topography using statistical parameters derived from atomic force microscopy(AFM)measurements.Using this computational model,the effects of roughness and surface patterns on bacterial attachment were examined quantitatively in both static and flowing fluid environments.The results have shown that rougher surfaces(within the sub-microscale)generally increase bacterial attachment in static fluid conditions which quantitatively agrees with experimental measurements.Under flow conditions,computational fluid dynamics(CFD)simulations predicted reduced convection-diffusion inside the channel which would act to decrease bacterial attachment.When combined with surface roughness effects,the computational model also predicted that the surface topographies discussed within this work produced a slight decrease in overall bacterial attachment.This would suggest that the attachment-preventing effects of surface patterns dominate over the adhesion-favourable sub-microscale surface roughness;hence,producing a net reduction in adhered cells.This qualitatively agreed with experimental observations reported here and quantitatively matched experimental observations for low flow rates within measurement error.

Particle properties in granular activated carbon filter during drinking water treatment

The elemental composition and bacteria attached in particles were investigated during granular activated carbon （GAC） filtration.The experimental results showed that trapped influent particles could form new,larger particles on GAC surface.The sloughing of individuals off GAC surface caused an increase in effluent particles in the size range from 5 to 25 μm.The selectivity for element removal in GAC filters caused an increasing proportion of metallic elements in the effluent particles.The distribution of molar ratio indicated a complicated composition for large particles,involving organic and inorganic substances.The organic proportion accounted for 40% of total carbon attached to the particles.Compared with dissolved carbon,there was potential for the formation of trihalomethanes by organic carbon attached to particles,especially for those with size larger than 10 μm.The pure carbon energy spectrum was found only in the GAC effluent and the size distribution of carbon fines was mainly above 10 μm.The larger carbon fines provided more space for bacterial colonization and stronger protection for attached bacteria against disinfection.The residual attached bacteria after chorine disinfection was increased to 10 2-10 3 CFU/mL within 24 hours at 25°C.