1:30 pm – 2:00 pm:
KEYNOTE: Medical Tubing Process Optimization with Simulation
John Perdikoulias, Compuplast International Inc.
The presentation describes the procedure that was used to optimize a medical tubing extrusion process and shows how simulation was used to quantify a polymer degradation problem and then evaluate solution options. An existing multi-lumen tubing die was also analyzed and optimized to improve production rate and process stability.
2:00 pm – 2:30 pm:
Systems Engineering for Medical Device Development: Application to Insulin Pumps
Marc Horner, ANSYS, Inc.
Ensuring product integrity across every component, subsystem, and system of a medical device has never posed a greater challenge. Engineering organizations are addressing this challenge by increasing the use of modeling and simulation tools across the entire product architecture and throughout the product development cycle – from functional analysis through detailed design to system verification. This approach necessitates the use of a broad array of physics modeling and other software tools. And while each individual tool may be effective at performing deep comprehensive analysis, product groups are often operating in silos, each using their own set of tools, engineering processes, and associated expertise to understand their areas of product performance. This approach can delay the understanding of the complete system, leading to delayed timelines, redesigns, and other unwanted outcomes. Using an insulin pump as an example, this talk will review how digital prototyping and systems engineering can address the needs of interdisciplinary product development teams. This more holistic approach enables engineers from diverse backgrounds to share expertise and experience as they design an optimal product.
2:30 pm – 3:00 pm:
Effects of the Biological Environment on Thermoplastic Polyurethanes
Ajay Padsalgikar, Abbott
Implantable thermoplastic polyurethanes (TPU) have been utilized in the medical industry for decades due to their combination of biocompatibility, abrasion resistance, and processability. Attempts to improve the biological stability of TPUs have been an area of intense activity and have resulted in a number of different formulations [1-5]. It has been observed that the nature of the soft segment in the TPUs is the primary factor in controlling the biostability of the final polyurethane. In many studies [5 – 9] it was seen that siloxane based soft segments presented the best performance in in vitro and in vivo tests and materials based on siloxane based soft segments are most suitable for long term implant applications. In this study, the results from various in vitro and in vivo tests are put together focusing on the performance of a siloxane based TPU (Optim) in cardiac lead insulation applications. The performance of Optim is compared with other materials, primarily polyether based TPUs.
3:00 pm – 3:30 pm:
Accounting for Differences in Modulus and Stress Relaxation Behavior in Plastics Undergoing Chemical Resistance Testing
Mark Yeager, Covestro LLC
Chemical resistance testing via strain fixtures ranks resistance based on the maximum strain at which the plastic can resist an applied strain without loss of mechanical integrity or appearance. While this comparison works well for materials within a family of plastics, such as unfilled polycarbonates, it can be misleading when comparing materials that differ in stiffness and stress relaxation properties. Adjusting for these differences yields a more realistic chemical resistance ranking for most applications.
3:30 pm – 4:00 pm:
Degradation Products of Medical Devices in Complex Biological Environments: Risk Assessment Strategies
Adam Kozak, Cambridge Polymer Group
There is growing interest in the identification, quantitation, and risk assessment of leachable species and degradation products of polymeric medical device components. Degradation and extractable & leachable studies usually follow a two-step program. In the first step, an exaggerated extraction is conducted using simple solvent conditions more aggressive than those anticipated to be realized in a clinical setting in order to determine the complete extraction profile and to identify the potential extraction compounds, desired or undesired. In the second step, a leaching study is conducted that attempts to simulate the clinical environment of the target application. The simulated leaching environment often comprises a more complex biological matrix than those used for extraction, which in turn complicates the chemical analysis assays used to identify and quantify the leaching materials. In this presentation, we show examples of studies that required a more detailed testing assay to identify and quantify compounds coming from implanted medical devices.
4:00 pm – 4:30 pm:
Accelerated Aging of Medical-grade Resings: Q10 Factors and Material Aging Models
Rob Klein, Stress Engineering Services
Accelerated aging is used throughout the Medical Device sector and other sectors to evaluate materials and devices in an accelerated fashion. If used properly, it can shave years off of validation efforts. If used improperly, it can generate misleading or completely incorrect data about the resins and products in question. This paper explores the fundamental principles and provides supporting data. It is critical to understand the four primary modes of aging for polymers: (1) physical aging (embrittlement and loss of free volume); (2) chemical aging, which includes oxidation, chemical damage, sterilization, etc.; (3) sustained strain cracking, creep rupture, and environmental stress cracking; and (4) fatigue. For sustained strain or sustained load environments, stress relaxation and creep are also key factors. A case study is presented for polycarbonate and copolyester resins that are undergoing physical aging, sustained strain cracking, and environmental stress cracking (ESC), and a model presented to account for the various factors.
4:30 pm – 5:00 pm:
Engineered Polymer Surfaces for Superior Performance in Pharmaceutical Applications
Prakash Iyer, Senior Vice President, Inhance Technologies
Inhance Technologies transforms polymeric surfaces to high performing solutions for pharmaceutical packaging, and medical disposables and device manufacturing, improving performance, and security. Using proprietary processes, the surface properties of plastics and elastomers are permanently activated, imparting high barrier properties, lubricity (slip) or bonding properties to facilitate longer product shelf life, preserve product quality, and increase functionality. This unique technology can additionally reduce overall product costs through material substitution and down gauging. This presentation will cover the technologies behind Inhance’s material transformations, the pharmaceutical applications currently utilizing these technologies as well as newer uses on the horizon. Inhance Technologies is a Responsible Care™ Company, ISO certified and operating in many countries around the world. Topics that will be covered during the talk include, – How barrier properties can be imparted to conventional plastics – How tenacious label adhesion and print are achievable for any plastic device – How to replace glass with high performing plastics for diagnostic, assay and medical devices – How silicone-free lubricity can be achieved on elastomer and rubber components.
5:00 pm – 5:30 pm:
Supercritical Carbon Dioxide Assisted Extrusion of Graphene Nanofiller Reinforced Polymers for Biomedical Application
Austin Coffey, Senior Member of Lecturing Staff & Principal Investigator , Waterford Institute of Technology
Over the years, the need for multifunctional medical tubing systems have grown tremendously subsequently increasing the precision tubing design and manufacturing consideration. The requirements smaller dimension along with enhanced mechanical and flexibility characteristics have resulted in elevating the complexity in manufacturing and design considerations, hence higher cost per device. A research gap exists in scientific understanding on the use of nanofillers to match similar characteristics medical tubes. This lack of understanding and industrial transition exists due to filler agglomeration at low aspect ratio and uneven dispersion within the polymer matrix. This study investigates ability of supercritical fluid technology to exfoliate graphene filler particles in order to enhance the mechanical, homogeneity and even dispersion of particles within Pebax matrix. A one step direct scCO2-assisted extrusion to exfoliate and provide even dispersion was demonstrated. These properties were verified using thermomechanical and electrical characterisation.
5:30 pm – 6:00 pm:
The Regulation of Micro-super-hydrophobic Silicone Rubber to the Behavior of Human Lens Epithelial Cells
Liuxueying Zhong, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzho
Purpose: Evaluate the feasibility of compression molding manufactured silicone rubber which the surface infiltrative characteristic is super hydrophobic, realize and compare the effect of super hydrophobic surface to several cellular biological characteristics of human lens epithelial cell line SRA01/04 with ordinary hydrophobic surface. Methods: The silicone rubber of super hydrophobic micro surface and ordinary hydrophobic surface were manufactured by Vacuum defoamation and compression molding, and tested the property of the surface by measuring contact angle, electron microscope scan experiment and evaluation transparency. In vitro, the effect of super hydrophobic silicone rubber on cell proliferation, cell adhesion ability and cell morphological changes by SRA01/04 cells were examined. Results: The surface contact angle of super-hydrophobic silicone was greater than that of smooth silicone (153.8 vs. 116). The super-hydrophobic surface exhibited a micron-scale palisade structureunder scanning electron microscopy. However, cell number per 50× microscopic field on super-hydrophobic surfaces was markedly reduced 24 and 72 h post-seeding compared to smooth surfaces (p<0.01). Cells were cuboidal or spherical after72 h on super-hydrophobic surfaces, and exhibitednumerous surface microvilli with fluff-base polarity, while cells on smooth surfaces exhibited morphological characteristics of EMT.Conclusions: This study applies compression molding manufactured the super hydrophobic surface silicone rubber successfully. The super hydrophobic surface inhibits cell proliferation, adhesion. It could be a novel way to prevent cells’ proliferation with mechanical mechanism. Acknowledgements:This project was supported by the grants from the National Natural Science Foundation of China (81400384).