Surface Properties of Biomaterials: Antimicrobial Coatings and Surface Analysis
Sponsored by: MS&T Organization
Program Organizers: Susmita Bose, Washington State University; Amit Bandyopadhyay, Washington State University; Thomas Webster, Brown University; Sharmila Mukhopadhyay, Wright State University; Paul Calvert, University of Massachusetts; Mukesh Kumar, Biomet Inc
Wednesday 8:00 AM
October 19, 2011
Room: C216
Location: Greater Columbus Convention Center
Session Chair: Amit Bandyopadhyay, Washington State University; Pranesh Aswath, University of Texas at Arlington
8:00 AM Invited
Surface Modification of Microneedles Using Pulsed Laser Deposition: R. Narayan1; Shaun Gittard1; Nancy Monteiro-Riviere2; Aleksandr Ovsianikov3; Boris Chichkov3; Bret Chisholm4; Shane Stafslien4; 1Univ of North Carolina & North Carolina State Univ; 2North Carolina State Univ; 3Laser Zentrum Hannover e.V.; 4North Dakota State University
Microneedles are small-scale devices that may be used for transdermal drug delivery of nucleic acid- and protein-based pharmacologic agents. In this study, microneedle arrays were fabricated using micromolding or rapid prototyping; pulsed laser deposition (PLD) was subsequently used to deposit silver, a metal that exhibits broad-spectrum antimicrobial activity, on the surfaces of the microneedles. Viability of human epidermal keratinocytes on PLD-modifed and unmodified surfaces was assessed using the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. In vitro testing revealed an absence of Staphylococcus aureus growth beneath the silver-coated microneedle array. Furthermore, inhibited growth was observed in the region surrounding the microneedle array, which was attributed to release of silver. Antimicrobial microneedles may be used in the treatment of diabetes mellitus and other chronic medical conditions.
8:40 AM
Anti-Bacterial and Biological Properties of Plasma Sprayed Silver-Doped Hydroxyapatite Coating: Mangal Roy1; Gary Fielding1; Amit Bandyopadhyay1; Susmita Bose1; 1Washington State University
Implant related infection is a key concern in total joint hip arthroplasties. In order to improve anti-bacterial and biological properties, silver (Ag) doping was used in plasma sprayed hydroxyapatite (HA) coating on titanium substrate. HA powder was doped with 2, 4 and 6 wt% Ag, heat treated at 800 °C and used for plasma spray coating using a 30 kW plasma spray system, equipped with supersonic nozzle. X-ray diffraction (XRD) study confirmed the phase purity and high level of crystallinity of the coatings. The microstructural analysis showed grain size of ~ 30 nm. Adhesive bond strength was measured to ensure mechanical integrity. The anti-bacterial activities of the coatings were evaluated using Pseudomonas aeruginosa. In vitro cell-material interactions and alkaline phosphatase (ALP) protein expressions were evaluated by culturing human fetal osteoblast cells (hFOB). The presentation will include physical and mechanical properties of the coating along with their anti-bacterial and biological properties.
9:00 AM
Improving the Resistance of Ceramic Surfaces to Biofilm Formation: Curtis Larimer1; Ian Nettleship1; Anil Ojha1; 1University of Pittsburgh
Biofilm formed by waterborne bacteria poses a significant challenge to healthcare and medicine. Biofilm is more resistant than planktonic bacteria to antibiotics and other antibacterials. Surfaces that resist or delay biofilm formation are critical in research on medical implants and water treatment. In this study silver nanoparticles were deposited on silica substrates by vertical colloidal deposition (VCD) and then their resistance to mycobacteria biofilm growth was examined under static and flow conditions. The coatings of silver nanoparticles ranged from full coverage (at least one monolayer) to submonolayer coverage. In a dual channel flow cell designed to ensure contact of passing bacteria with the antibacterial surface the initiation and growth of biofilm was observed on silver coated surface versus a non coated control surface.
9:20 AM
Anti-Bacterial and Biological Properties of Plasma Sprayed Strontium and Silver Doped Hydroxyapatite Coatings: Gary Fielding1; Mangal Roy1; Amit Bandyopadhyay1; Susmita Bose1; 1Washington State University
This research focuses on understanding the effects of silver oxide (Ag2O) and strontium oxide (SrO) doping on the anti-bacterial and biological properties of plasma sprayed hydroxyapatite coating. Hydroxyapatite (HA) powder was doped with 2 wt% Ag2O, 1 wt% SrO and a combination of 2 wt% Ag2O and 1 wt% SrO, heat treated at 800 °C for 6h and then used for plasma spray coating. A 30 kW radio frequency (RF) induction plasma spray system, equipped with supersonic nozzle, was used for these coatings. X-ray diffraction (XRD) study confirmed the phase purity and high level of crystallinity of the doped and undoped HA coatings. The microstructure and adhesive bond strength of these coatings were analyzed. Silver ion release was measured using atomic absorption spectrometry (AAS). Anti-bacterial activities of the coatings were evaluated using Pseudomonas aeruginosa bacteria. In vitro cell-material interactions were evaluated by culturing human fetal osteoblast cells (hFOB).
9:40 AM Break
10:00 AM Invited
Nature Inspired Hierarchical Surfaces for Biomedical Devices: Sharmila Mukhopadhyay1; Elizabeth Maurer2; Adam Maleszewsky1; Ian Barney1; Saber Hussain2; 1Wright State University; 2Air Force Research Laboratory
A large variety of elegant and multifunctional structures seen in nature have hierarchical architectures incorporating dendrites, capillaries, or other attachments. If similar structures are adopted in synthetic bio-materials, an immediate advantage will be orders of magnitude increase in surface area without increase in size. This increased surface can be functionalized with nanoparticles, proteins etc. for suitable biomedical applications ranging from tissue scaffolds, sensors to anti-microbial or drug-delivery agents. A key pre-requisite for success in this approach will be creation of robust structures with strongly attached nanotubes or particles on larger solids, followed by controlled functionalization. This presentation will discuss several different multi-scale structures being investigated for this purpose. They are based on carbon-based materials, but can be easily transferred to other biocompatible substrates. Several possible applications such as porous implants offering accelerated cell growth, protein-tethered structures for pathogen sensing, and nano-silver attachment for anti-microbial surfaces will be discussed.
10:20 AM
Antimicrobial Properties of Copper and Its Alloy: David Esezobor1; Samuel Fatoba1; John Etudor1; Solomon Macgregor1; 1University of Lagos
This paper studies the antimicrobial activity of selected metallic, polymeric and ceramic surfaces. It also examines the potential acquisition of copper by food substance exposed to this metal. The antimicrobial activity of materials’ surfaces was evaluated by overlying suspensions of the pathogens on copper, stainless steel, brass, ceramic and synthetic polymer. The results showed a significant reduction of bacterial concentration when human pathogens were kept in contact with dry copper surface at 10oC and room temperature. The amount of live bacteria drops by several orders in magnitude on copper within the first two hours. In contrast, almost no reduction was noticed in the concentration of live organisms on stainless steel, plastics and ceramic plates when the same load of pathogen suspensions, rather some pathogens grow with time. The acquisition of copper by food material experiment showed that the red meat adsorbed copper in a time dependent manner.
10:40 AM
Structure of Trabecular Bone in DMP-1 Deficient Knock Out Mice and Wild Type Mice: Megen Velten1; Paul Dechow2; Jian Feng2; Pranesh Aswath1; 1University of Texas at Arlington; 2Baylor College of Dentistry
Dentin matrix protein 1 (DMP1) is an acidic extracellular protein that is highly expressed in mineralized tissues. It is thought to be particularly important in the remodeling of trabecular bone. To further understand structural changes introduced into the bone matrix during the remodeling process, the femurs of female DMP1 knockout (KO) and wild type (WT) mice were characterized and compared. XANES spectroscopy was used to characterize the local coordination of P, Ca and O using the P L-edge and K-edge spectra, Ca L and K edge spectra and the O K-edge spectra. FTIR and Raman spectroscopy were used to characterize the differences in the phosphate and carbonate structure in the KO and WT mice. Acknowledgement: XANES experiments were carried out at the PGM, SGM and SXRMB beam lines at the Canadian Light Source which is supported by NSERC, NRC, CIHR and University of Saskatchewan.
11:00 AM Student
The Role of Bacterial Attachment to Metal Substrate and Its Effects on Microbiologically Influenced Corrosion (MIC) in Transporting Hydrocarbon Pipelines: Faisal Al-Abbas1; Arshad Bajvani Gavanluei2; David Olson2; Brajendra Mishra2; John Spear2; Anthony Kakpopovie1; 1Saudi Aramco; 2Colorado School of Mines
During oil and gas operations, pipeline networks are subjected to different corrosion deterioration mechanisms, one of which is Microbiologically Influenced Corrosion (MIC) that results from accelerated deterioration caused by different microbial activities present in hydrocarbon systems. Bacterial adhesion is a detrimental step in the MIC process. The MIC process starts with the attachment of planktonic microorganisms to metal surface that lead to the formation of the biofilm and subsequently results in metal deterioration. The tendency of a bacterium to adhere to the metal surface can be evaluated using thermodynamics approaches via interaction energies. In this paper, thermodynamic and surface energy approaches of bacterial adhesion will be reviewed. Also, the factors affecting bacterial adhesion to the metal surface will be presented. In addition, the subsequent physical-chemical interaction between the biofilm and substratum and its implication for Microbiologically Influenced Corrosion (MIC) in pipeline systems will be discussed.
11:20 AM
XPS and Cellular Characterization of Surface Anodized Titanium Alloys for Dental Implant Applications: Rahul Bhola1; Reed Ayers1; Brajendra Mishra1; David Olson1; Timothy Ohno1; 1Colorado School of Mines
Anodically treated titanium alloys (α, α+β and the metastable β) were implanted in to human fetal osteoblast cell cultures. The material tissue interface was evaluated using cell attachment under the SEM and X-ray photo-electron spectroscopy. Ca and P were detected on all materials after in vitro cell culture. TiO2 is present as the dominant phase over all the metal samples.
11:40 AM Cancelled
Surface Analysis of a Beta-Titanium Biomaterial: Kallen Konen1; Keeley Floreen1; K.V. Sudhakar1; 1Montana Tech
Ti-3Al-8V-6Cr-4Mo-4Zr alloy is an important beta type titanium material that is used in biomedical applications. Surface properties are important to understand since cells interact with the material surface first. This is helpful in understanding the bioactive response of the synthetic biomaterial. The investigated alloy was subjected to different heat treatment cycles. One was annealed at 8000C-1hr and was then cooled in air, the other one was solution treated at 8500C-1 hr and aged at 5000C-8 hr, and the final sample was not subjected to any heat treatment. Optical microscopy was carried out to characterize the effect of heat treatment and its influence on grain size. Tests were then conducted to evaluate the chemistry and grain size effects on biomaterials. Texturing and surface functionalization were analyzed. Surface roughness studies were conducted using the digital HiRox microscope. The reactivity and/or wear of the surfaces will also be evaluated.