ChemSemBlog

This week was our first time in Chemistry Seminar for 2010, and everyone appeared to be a tiny bit groggy and perhaps not totally ready to jump in and ask 6 questions. Whether your burden is Chemistry Seminar or a frightful bone injury requiring polyaryletherketone implants, life does go on–sometimes without you!

And with that painfully transparent intro, I segway into the talk given by our guest speaker in ChemSem this week, Ryan K. Roeder. Roeder has been conducting research into different ways in which to increase the strength of implants used in bone. In contrast to the types of implants used orally for artificial teeth, bone implants are not made from stainless steel or any kind of mixed transition metal alloy. In addition, this method does not employ the traditional procedure of removing bone from elsewhere in the patient to use in place of lost or decaying bone, a procedure known as autografting.

Rather, Roeder’s work takes him into the field of composite implants which utilize materials capable of expanding and contracting in a very similar fashion to that of real bone. Roeder’s work has led him to use an aromatic class of polymers known as polyaryletherketones. Traditionally, these were used as simple “pins” in bone. However, Roeder mixed this older method with a newer one which involves the diagonal implantation of these composite rods. The mere physics of the procedure validates its usefulness. Multiple randomly-oriented diagonal rods will increase the resistance of the implant to longitudinal tension, thus strengthening the connection while still using the same composite. This technology could improve a proven science for orthopedic patients everywhere.

I felt that the presenter did a decent job of presenting the material. He had the attention of the students much of the time because of the simplicity of the chemistry and the abundance of healthcare-bound members of the audience. I felt that this presentation was slightly less rooted in chemistry than some of the others, but it was still applicable to those present.

To the layperson, this seminar was about new ways to use materials in bone surgery to make them work better.

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Dr. Ryan K. Roeder gave the chemistry seminar on January 14, 2010. He is an associate professor of Aerospace and Mechanical Engineering at the University of Norte Dame.  He received his bachelor degree and Ph.D. in Materials Engineering at Purdue University. Following that, he completed a post-doctoral research in the Department of Orthopedic Surgery.

The presentation that he presented to us was very interesting and informative, which was dealing with implants for spinal fusion. He mainly talked not only how the replacement for bone was synthetically created and what environment is required to create an implant that is very similar to our actual bone.

According to his presentation, variety of materials such as metals, ceramics and polymers can be used in orthopedic implants. However, there were a lot of disadvantages on using metals and ceramic as compare to polymers. So, he proposed on creating new implants that are made with polyetheretherketone, which is PEEK.  IT has the same strength and durability as human bone which helps the bone will not degrade. Since PEEK is not bioactive, it needs to be combined with hydroxyapetite so the cells from the bone with attach to it and be integrated through the implant to fuse the bone. Furthermore, through the whisker synthesis that Roeder and his team found, they could combine Hydroxyapatite crystals can be combined with PEEK to create a new material.

Overall, this seminar was really helpful and engaging. The speaker was also enthusiastic about his presentation and also was good at responding to students during question and answers at the end of the seminar. I learned how the implants for spinal cord were made and what kind of material they use. I just had few questions such as, how long it would take to make one implant and how much cost for one implant.

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Ryan K. Roeder is the head of the Department of Aerospace and Mechanical Engineering and Bioengineering Graduate Program at the University of Notre Dame in Notre Dame, Indiana.  Mr. Roeder is a young man who brought a lot to the table about the topic of Implants for Interbody Spinal Fusion. Ryan Roeder has been a part of the faculty at the University of Notre Dame since 2001 and has taught courses there on bio materials, failure fo materials, mechanical behavior of materials, manufacturing processes for materials and solid mechanics.  Ryan Roeder’s primary research is broadly centered on processing, structure, and property relationships in synthetic bio materials and biological tissues.

This talk however was pointed most directly at spinal fusion.  The challenges of spinal fusion is being able to create a material that is “soft” like bone but that is rigid enough to withstand stress.  Also, other major challenges are creating a material that that body is willing to accept also.  If the structure is too strong then the bone around the implant will gradually deteriorate and wither away.  This creates even more trouble for  a person.  So Mr. Roeder created an idea that he feels will work best.  He is using PEEK which is a Poly Ether Ether Ketone chain.  This material is strong but also “soft” and is very similar to bone.  The PEEK is not what the body or bone looks for to be the material that it attaches to.  The material is found within the PEEK solid material.  They created a stem system that is found within the PEEK that gives the bone something to connect to.  This obviously takes time to happen in the body but once it does the spinal column will be strong once again.  These implants do tend to limit the motion of an individual but when a person is looking at no movement compared to limited movement almost anybody will choose the limited movement over having no movement and these implants are allowing people a last chance resort to fix severe back issues.

Mr. Roeder spoke excellently and answered all the questions with ease.  He knew his materials and was very prepared.  He was extremely easy to understand and to follow.  His abilities to time manage in order to fit everything in within the time constraints was a major plus and I would rate his performance as a 9.5 out of 10.  Great enthusiasm and he seemed to be a really great guy.  He evened stayed after the lecture to answer more questions from the students.  Excellent speaker and excellent topic.

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On January 14, 2010, there was a presentation about disk implants given by Ryan K. Roeder, who is from University of Notre Dame. His presentation title was “Porous and Bioactive Polyaryletherketone Implants.” It was very interesting that the theme of his seminar is related to the material which is used practically in our daily lives. Overall, his presentation attracted me because he explained the way which his product is used as well as the way which he has developed to synthesize the material with various conditions.

He started the seminar introducing the students to the materials which are commonly used when doctors operate on implants. These are metal, ceramics, and polymers. Each of these materials has their own strength and weakness. Especially, whether the material is injectable and bioresorbable, are two standards for implants. One of the products his research focuses on is Polyaryletherketone. This is a good material for replacing disks located between backbones, because it is biocompatible, and bioinert. In addition, it has higher strength than other materials.

In synthesizing Polyarlyetherketone, Roeder changed many variables to obtain the most suitable material for implant in a human body. In variables, there are porosity, amount of HA, and temperature which the material is synthesized at. In particular, the temperature effects on the sintering and mechanical integrity. At higher temperature which is about 375 Celsius, both sintering and mechanical integrity increase.

I would tell my friends that as we grow older, the materials which help supporting our bodies between the bones that are worn out. Therefore, as the level of medical technology increases, the we can discover materials which are able to replace bone.  Roeder’s work takes us down that path.

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The presentation by Dr. Ryan K. Roeder was about using polyaryletherketones as an implant for interbody spinal fusion. The speaker is a young faculty at the University of Notre Dame, and he has taught courses on biomaterials. He has done two year post-doctoral research in the department of orthopaedic surgery at the Indiana University Medical Center which shows his credibility as a speaker for the presentation topic. I thought the speaker’s presentation was a little fast, but it was very professional, enthusiastic, and understandable.

Polyaryletherketones is used clinically for composite hip stems and interbody spinal fusion cages. Structure of the bone tissues included trabecular bone (porous bone on the joints), cortical bone (dense bone composed of osteons, haversian canals, mineralized collagen fibers).

I learned that there are two kinds of implant materials: nonresorbable and bioresorbable. Nonresorbable material was the one that cannot be absorbed by the body, while bioresorbable gets absorbed by the body to replace the material as time passes. I also learned that bones are not just a piece of hard stick. I learned that it is actually somewhat flexible, and it gets fatigued and stressed as we use it, requiring constant tissue repair.

Three questions I came up with included 1) how long does these implant materials last (nonresorbable vs. bioresorbable ones, if bioresorbable ones needs to be replaced), 2) do any of these implant materials that gets put into the body cause allergic reactions?, and 3) how does the flexibility of the implant material compared with that of the original one.

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This week’s presentation, and the first of this new year 2010 was given by Dr. Ryan K. Roeder, an associate professor of Aerospace and Mechanical Engineering at the University of Notre Dame. His presentation had to deal with implants for interbody spinal fusion, focusing specifically on Polyaryletherketone and Hydroxyapatite. The main idea of his presentation was to show us students how to synthetically create a replacement for bone, and how to manipulate the materials and environment to create an implant that is very similar to the actual bones in our body.

The research that Roeder is involved with is creating new implants that are made with polyetheretherketone, known as  PEEK. It has about the same strength and durability as bone, so the bone will not degrade. PEEK is not bioactive, so it needs to be combined with hydroxyapetite so the cells from the bone with attach to it and be integrated through the implant to fuse the bone. The hydroxyapetite needs to be integrated into the PEEK in whisker like crystals, so they will not fall off the PEEK and will still provide surfaces for the bodies cells to attach to. The implant also needs to be porous so that blood vessel can grow through it and extend to the rest of the body.

Overall, this seminar was very well presented. There were many chemistry and engineering aspects but the information was given in a way that facilitated general understanding of the science required to make these spinal fusion implants. It was enjoyable to have a seminar focused on a biotechnological subject that is easy to comprehend.  I personally enjoyed this seminar and would definately look forward to Dr. Roeder presenting again in future seminar periods.

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Dr. Ryan K. Roeder started this term’s ChemSem presentations with his work on bioactive synthetic bone replacements. Though the field of prosthetics and synthetic tissue surgeries has been growing rapidly in the past few years, bones are still currently augmented with metal rods or simple polymers. The rods are much harder than regular bone, causing the bone around them to deteriorate from disuse, the polymers are much softer than regular bone creating potential for creep failures as well as failing to bond to bone in any way. Dr. Roeder’s method involves imbedding hydroxyapatite ‘whisker’ crystals in the surface of the polymer since bone cells have an affinity for the calcium in the crystals. This binding creates a mechanical bond between the synthetic and biological components strengthening the supplement. Much of the presentation discussed the research and ways of developing this polymer.

The presentation itself was very good. Dr. Roeder explained things well and went into mostly sufficient detail. I still found curious the types of alcohol he used for an initial solvent in creating the polymer. Furthermore, I wanted to know about the shear strength of the material considering it has never been tested under such loading. In the case of vertebral bone, shear is a small issue, but if the material were applied to longer and larger bones, it would be important to understand its resistance to side loading forces. Finally I was curious what the cost of the development and continuing production of the PEET polymer with whisker crystals was to understand the financial burden the research of it entails.

Overall the ChemSem was interesting, well presented, and kept the audience engaged and focused. The research that is being conducted seems valuable and applicable on a wide scale. Unfortunately, it seems the product itself is still some distance from being available for use in surgery.

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The lecture this week was very interesting and informative, mainly because of its highly practical nature and the processes by which the chemicals are created. I must admit that at first I wasn’t too excited from just looking at the title of the lecture, but as soon as the speaker began I found that my first impressions were wrong.

One of the things that I learned was that in order for the implants to work effectively they must be able to fuse with the bones they are helping. To do this the polymer substance must be embedded with shards of calcium materials that fuse with the bone and lock the implant into place. Another thing that I learned was that the implants are made with both polymer and ceramic components, the mixture of which allows the material to be as rigid as the design needs it to be.

One thing that I would like to learn more about is what makes polyetheretherketone have similar properties to bone, thus making it a good substance to use for the construction of implants. If I were to describe this lecture to one of my non-science friends, I would say that the lecture was about how the material used in spinal implants was developed and how it works.

As for the speaker, Dr. Ryan K. Roeder works in the Department of Aerospace and Mechanical Engineering and Bioengineering Graduate Program, at the University of Notre Dame, Notre Dame, Indiana. His speaking style was smooth, to the point, and very imformative. He really knows what he is talking about and seems genuinely interested in the topics he was presenting. All in all, the lecture was superb.

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This week’s presentation (January 14, 2010) was given by Ryan K. Roeder, who is an associate professor of Aerospace and Mechanical Engineering at the University of Notre Dame. His presentation was about implants for interbody spinal fusion, focusing especially on Polyaryletherketone and Hydroxyapatite. The main point of his presentation was to show us how to synthetically create a replacement for bone, and how to manipulate the materials/environment to create an implant that is very similar to the actual bones in our body.

According to his presentation, orthopedic implants use a variety of materials, including: metals, ceramics, and polymers. He went on to say that there are disadvantages to each material. For example, metals are stronger than bone, causing the body to depend too much on the metal and not create any bone near the metal. Therefore, he proposed a polymer called Polyaryletherketone (PEAK) and Hydroxy-Apatite (HA). He stressed that the advantages of using PEAK are many, including the fact that it is: biocompatible, radioluscent, high in strength, and similar to bone. The challenge for spinal fusion implant, is that the material being implanted needs to be similar in strength to bone. However, polymers are usually weaker than bone, especially when compared with metals. Even though PEAK is more similar to bone than for example, metals, he proposed that by reinforcing the polymers with another material, the similarity could be further increased. For the reinforcement, he introduced a synthetic Hydroxy-Apatite, that was whisker shaped by manipulating it through chemistry.

Overall, his presentation was very interesting, and engaging. The other students also seemed very attentive and interested in the topic. Although this topic was altogether new to me, I was very interested, and would definitely love to have an opportunity to do research in this area.

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The speaker this past Thursday was Ryan K Roeder, a professor from the University of Notre Dame’s Department of Aerospace and Mechanical Engineering. His presentation was engaging both in topic and style. He was able to deliver the topic in such a way to appeal to students of chemistry despite having heavy engineering aspects to it, and was able to organize his presentation in such a way to keep the audience attentive by bringing to life the research he conducted.

We were able to learn the background of what spinal fusions are as well as the current implants that are being used. From there Roeder was able to illustrate the problems with current implants, and explain the motives for his own research. I found his research interesting because it was able to combine chemistry and engineering in order to accomplish the goals. We were able to learn more about PEEK and calcium phosphate and how they sought to combine them in such a way to make it similar to bone, also I was able to learn new things about spinal fusions as well as possible other applications for PEEK.

It seemed evident that other people thought the topic was interesting just from the amount of questions asked. If I were to describe this presentation to my non science friends I would say that it was about creating better materials in order to use for implants in interbody spinal fusion.

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A spinal fusion is something I hope to never encounter, but for some Americans it is an easy trade off for the pain they had been enduring due to continuing neck and back pain. Just as revolutionary spinal implants were originally, so is the need today for new innovative device materials that better fulfill the job of the implant. Currently used  biomaterials in orthopedic implants are: ceramics, metals, and polymers. Ryan Roeder, Ph.D.  faculty at the University of Notre Dame in the Department of Aerospace and Mechanical Engineering, has zeroed in on polymer implant and device design emerging with a novel new device and design.

The goal of osteointegration is vascularization( 70-90% porosity), cell adhesions, osteoinduction, and bioactivity.  Bioactivity means that the substance elicits a favorable response from the body. Also, a good material is one that is as stiff as bone so that the current bone does not degenerate when the new material is implanted, as is the case when metal is inserted into the spinal.

Polyetherketones (PEEK) used clinically for composite hip stems and interbody spinal fusion cages, is great because it can been seen radiographcially after surgery (as opposed to titanium) and its elasticity is similar to bone, unfortunately it is also very dense. Roeder and his research team created a method called the whisker Synthesis to combined whisker-shaped hydroxyapatite (HA) crystals with PEEK to create a new material possessing the best properties of both compounds singularly.

Summarizing their chemistry, the whisker synthesis is conducted by combining the compounds Ca(OH)2, H3PO4, and lactic acid (the carboxylic acid binds the Ca2+ which keeps it from precipitating too soon) with no agitation at a temperature of 200 degrees Celsius for two hours.  The morphology of the resulting crystals can easily be controlled by how the solution is heated. Quickly heating the crystals decreases the crystal length; a longer heating rate corresponds with long, thin crystals. Roeder’s team also tried another approach to the whisker synthesis, by using a powder form of HA and PEEK, however this method proved to not be as effective. Molding temperature has also proved to be very important in synthesizing an ideal material. At lower molding temperatures (350), polymers do not adhere well to each other; however, crystals on the whiskers containing phosphate are exposed, this is crucial because cells like phosphate and will attach to it forming new bone around the implant.  On the flip side, at higher molding temperatures (375) cell adhesion is improved dramatically, but none of the whiskers are exposed. Currently Roeder and his research team are determining a balance between the two that will be of optimal use.  Once the right combination of HA and PEEK was established Roeder then added salt crystals to the solution which would be washed out later, leaving a very porous material.

Thursday’s lecture was very interesting and informative! I learned the qualities needed for osteointegration, the need for newer spinal fusion technology, and the intricacies of the whisker synthesis. The only questions I have are #1. Where does he see his research going in 10 years? #2. Is it possible to either transform this into an injectable material or create one? And finally,  #3. is there a way to regulate bone growth around the implant?

We started off our seminar chemester (too good to pass up) with a bang, thanks Dr. Roeder for stopping by!

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This presentation was about certain implants for bone so that spinal fusion can occur. The speaker was Ryan. K. Roeder, a younger gentleman that discovered he had a passion in materials engineering. He works at Notre Dame, in the department of aerospace and mechanical engineering.

Currently his research involves processing structure property relationships in synthetic biomaterials and biological tissues. I found this topic to be very interesting.

During this presentation we learned that the biomaterials used in orthopedic implants consist of metals, ceramics, and polymers. Roeder believed that back pain was the number one reason people can’t work. His research consisted of developing a component that would cause bone to grow. They want to develop this component to be placed in between the space of the spinal bone. They have to make sure that this component is biocompatible as well as bioactive. We learned of the hierarchal structure of bone tissue and the ways they can be separated. Bone tissue is separated based on injection and absorbity. I also learned of HA whisker synthesis and that they used carboxylic acid binds the calcium ion so they can control the morphology of the crystal peek in crystal morphology. It was interesting how this process was found to suspend, isolate, and compress.

At the end of this presentation many students seemed to be engaged and really enjoyed the topics being discussed. During the question and answer period the speaker was able to answer all the questions and clarify information that students were confused on. Although I wasn’t encouraged to learn more about the topic or go to the speaker’s school of graduate studies, I found the information to be attention-grabbing. I felt that spinal fusion research is important and can benefit many people in the future.

This presentation was about research that will help solve people’s back problems by developing components that will help fill the space between the spinal bones.

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Ryan Roeder came and talked about “Porous and Bioactive Polyaryletherketone Implants for Interbody Spinal Fusion” and the research he has done for it. What he and his colleagues are trying to make is an implant that can be used for people who experience severe back pain because their inter-vertebral disk has worn away and their spinal cord or nerves are being pinched when they move.

What has currently been used in such replacement procedures are products made with stainless steel, Co-Cr alloys, Ti, or Al. The problem with these materials is that they were the first to be approved and they are not necessarily the best. The harder metals take most of the stress that the bones would normally take, and when this happens the bones are no longer needed and they degrade.

The research that Roeder is involved with is creating new implants that are made with polyetheretherketone, or PEEK. It has about the same strength and durability as bone, so the bone will not degrade. PEEK is not bioactive, so it needs to be combined with hydroxyapetite so the cells from the bone with attach to it and be integrated through the implant to fuse the bone. The hydroxyapetite needs to be integrated into the PEEK in whisker like crystals, so they will not fall off the PEEK and will still provide surfaces for the bodies cells to attach to. The implant also needs to be porous so that blood vessel can grow through it and extend to the rest of the body.

It was a very interesting seminar, with both chemistry and the mechanics for what is being done to make these implants. I would explain this seminar to a non-chemistry friend as being the development of implants to use in the spinal column to relieve back pain.

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Chemistry Seminar on January 14, 2010 was presented by Ryan K. Roeder from the University of Notre Dame Department of Aerospace and Mechanical Engineering Bioengineering Graduate Program. The program is in place to design biomaterials that can be used as orthopedic implants.

These types of implants can be made from metals, ceramics or polymers. The presentation focused on the use of the polymer Polyetheretherketone, also known as PEEK, for spinal fusion implants. Roeder informed us of the advantages and disadvantages of this polymer. Some of the advantages to PEEK are that is its biocompatible, bioinert, has high strength, and has a modulus similar to bone. Some of the disadvantages are that it is not bioactive and BMP or autografting are required.

To give the polymer strength whisker shaped crystals are added to the PEEK polymer. This improves the fatigue life by 4 or 5 times. This means that the implant can withstand a greater amount of loading and unloading pressure. The crystals are made from a calcium compound which encourages binding of new bone to the implant. To make the material porous and bone like salt is added to the solution which can be dissolved out leaving holes in the polymer. Roeder’s research group is currently working on making round salt instead of the standard cube shape so bone can adhere more actively to smooth round holes in the PEEK.

This seminar was very well presented. There were many engineering aspects but the information was given in a way that facilitated basic understanding of the science required to make these spinal fusion implants. It was enjoyable to have a seminar focused on a tangible subject that is easy to comprehend. In telling friends and family about this seminar I would say that it described a new way of making implants to replace disks in the spine.

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The first speaker of the new semester was Ryan Roeder from Notre Dame.  His topic was on porous and bioactive polyaryletherketone implants for interbody spinal fusion.  Spinal fusion is a last ditch effort to relieve a patient’s back pain.  Various metals, ceramics, and polymers can be used as orthopedic implants.  The main focus of Roeder’s study was using polyetheretherketones (PEEKs) and polyaryletherketones (PAEKs).  These materials are biocompatible, meaning that the body will not attack them.  They have a high strength and are able to bear physiological loads without mechanical failure.  However, an autograft is required to osteointegrate PEEKs and PAEKs.  To assist with spinal fusion, hydroxyapatite “whisker” crystals are made in the same chemical manner that the body makes bone.  In his research, Roeder discovered that when synthesizing the crystals, a high heating rate will produce a low crystal length.  So, to make longer crystals, the heating rate must be gradual.  Also, a large amount of fatigue can cause the crystal structures to fail.

Roeder was very professional in his presentation and answered each question thoroughly.  The presentation topic is of great interest to me, as spinal fusion might be used one day to relieve back pain.  When I’m 62 instead of 22, I will likely need such a procedure.  There are a few questions I have regarding the research.  The first is how much strain can a PEEK or PAEK handle before it fails as an orthopedic implant?  Second, what porosity is ideal for the hydroxyapatite crystals?  Finally, are there any materials similiar to hydroxyapatite that could also be used for making the whisker crystals?

Overall, I give this presentation two thumbs up.  To sum it up for a layperson, this project is about making strong implants for spinal fusion in order to relieve back pain.

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