We need to bond a silicone insulator between two gold-plated electrodes. All materials need to be medically approved for nonimplantable use. Can you recommend options to explore?
I would recommend a silicone adhesive to bond the silicone insulator to the gold-plated electrodes. Two possible candidates are Dow Corning’s medical adhesive Type A (an acetoxy cure system) and NuSil’s Med1-4213 (a two-part platinum cure system). Both materials are themselves insulators.
It’s been a number of years since I’ve worked with silicone, so forgive my ignorance. Are there any major providers of systems—i.e., Stratasys, etc.—that manufacture rapid prototyping systems, other then subtractive, that are capable of producing/curing m
Statasys and other companies, I believe, do offer rubber or “siliconelike” materials called TangoPlus, Tangogray, and TangoBlack. The resolution and accuracy available are generally good enough to help validate a design, but they are not a replacement for an actual silicone part. As far as why they have not made a rapid prototyping system for silicone, I am not entirely sure. I am guessing that it is due to the peanut butter consistency of silicone in its uncured state. I am sure that it would be very difficult to lay down a thin enough layer to accurately create a part, not to mention then having to heat it up to cure it.
I am currently working on a medical device in which a needle pierces through a silicone septum. I can’t use silicone oil. Is there any other medical-grade lubricant that can be used to aid the needle through the silicone?
I am not aware of any other medical-grade lubricant. One additive we sometimes use in applications is Zonyl. Teflon can also be loaded into the silicone prior to molding (~15% by weight). This creates some added lubricity throughout the part.
Is there a good way to surface treat silicone in order to make the surface more dirt resistant so that it will not pick up fibers and other debris easily?
A mat finish versus a polished/shiny finish will pick up slightly less FM or “dirt.” There are also surface treatments such as a parylene coating that create a lubricity on the surface and coat the silicone part. The use of ionizing fans to reduce static when handling the part will also reduce FM instances.
It appears that there have been ‘legacy’ materials in widespread EU medical market use—for example, PVC-based tubing and gloves—for more than three decades. However, they are expected to fail the latest ISO 10993 biocompatibility testing, where PVC is sug
Several materials are known to show signs of toxicity in certain biocompatibility tests but are still safe to use. The best examples are latex and nitrile. Latex is the positive control for the cytotoxicity test, and nitrile gloves fail the hemolysis test, yet these materials are still acceptable medical device materials. The first thing you must do is show that the known problem material is not ‘hiding’ other toxic components. This is done by removing the problem material from the test in which it is known to show a positive result. Then, you can evaluate the other materials and processes to determine that the results are being derived from that one problem material only. After that, you can use either an industry search or expert opinions to justify the acceptance of the failure.
We are ready to perform biocompatibility testing on a new catheter-securement device and need to know which tests must be performed and which can be skipped. This is a Class I device consisting of a skin adhesive bandage (3M) topped with a polypropylene l
We would do agar overlay for cytotoxicity, skin sensitization, and primary skin testing, and that’s all.
We currently employ a solvent process using cyclohexanone to bond PVC tubing with an ABS molded hub. We are going to be switching from ABS to Pebax (thermoplastic elastomer). However, because we believe that there are issues with the cyclohexanone creatin
Solvent bonding typically works with amorphous thermoplastics such as PVC, ABS, PC, PMMA, and PS. Pebax belongs to the family of thermoplastic elastomers and generally offers good resistance to solvents. Depending on its grade and softness, it may swell in certain solvents but will not behave like amorphous thermoplastics do. If you replace the ABS with Pebax, you need to switch to a new bonding process. UV-light curable adhesives are a good option, and I would recommend that you try Dymax medical-grade adhesives 204-CTH-F and 209-CTH. They both adhere well to PVC, Pebax, and several other commonly used plastics.