Day 8 – The End of the Journey

Today marks the final day of my brief yet incomparable time at Chesterfield. I started the day continuing to use the Lulzbots with Natalia. We printed another cylinder out of PCU for dog bone testing and finally got the other printer to work properly! For that one, we used a slightly different polymer that was more rigid at room temperature. Instead of printing a cylinder that would be cut into dog bones later, we directly printed dog bones onto the second Lulzbot, even though they did not turn out great (many of the samples ended up breaking). Natalia also fixed the other material extrusion printer that can go up to 600*C at the nozzle for printing special polymers, and we started some dog bone prints on that as well.

As we waited for the prints to finish, she explained to me some of the science behind the data analysis. There are two main things of importance when analyzing the data from mechanical testing of these dog bones: the stress vs. the strain. The strain is how much distance the sample moves while the stress is the amount of force used by/exerted on the object. As depicted in the graph below, the stress is the y-axis variable and the strain is the x-axis variable. Stress is measured in Megapascals (a standardized measurement of force) and strain is measured in millimeters. The x-mark on each curve represents the stress and strain at which the material breaks. The linear representation of glass in the graph reveals its brittleness: low strain yields high stress because it will break under a lot of force without stretching much. A material like rubber, evidently, will stretch more even when experiencing less stress. The unique corner on the aluminum curve represents the yield strength: the point at which the material will no longer return to its original shape after being stretched since the strain has exceeded the material’s ability to repair. Another interesting note is that the “stiffness” of each material is represented by the slope of the curve before the yield strength.

That’s basically all we did today! It was concise but fun at the same time. What strikes me is that my experience in the past eight days has been so much more beneficial than I had anticipated. I did not expect to understand so much of the information I was given, and it inspires me that there are such dynamic lab groups working on extraordinary projects that are truly aimed towards helping humankind. I think the bigger picture is what got me; the people I met here at Chesterfield are not motivated by publishing papers or pursuing degrees. Rather, they cherish the excitement that comes from developing devices that they know will go to help those in need. I sure will remember all the phenomenal educational learning opportunities I have had, and I definitely will not forget the benevolence and dedication of all the people I have worked with throughout this journey.

Day 7 – Successful Troubleshooting

My visit to Chesterfield was an exciting one today. I worked with Natalia, a PHD student who explained to me various forms of 3D Printing and their pros and cons. See the photo below for a detailed chart of the main different types. For reference, I have worked with Material Extrusion (ultimaker), powder bed fusion (titanium printer), and vat photopolymerization (the carbon printer). Natalia explained how different printers have different tendencies to create structural defects and she is researching how to address and minimize these inconsistencies. For example, material extrusion printers result in printing by layer, so the x and y axis of the structure are relatively strong, but the z-axis may be weaker since the space between layers allows structural weakness. Natalia is testing what settings would be most optimal for printers to minimize this decrease in “weld strength.”

Natalia is currently working with three different materials: PCU (Polycarbonate urethane), the flexible but fairly strong polymer I worked with Friday, PEEK (Poly ether ether ketone) an crysalline polymer, and PEKK (poly ether ketone ketone), an amorphuous polymer. The latter two materials are unique in that they require much higher temperatures than the average 200*C to melt. Normal material extrusion printers can’t attain a temperature that high on their nozzles, so a special material extrusion printer with an enclosure and extra heated build plate is required to print PEEK and PEKK, going up to 450*C. Unfortunately, this printer had some teflon stuck in the spool feeder, so we had to put the whole tube in the oven at 190*C to melt it out. Luckily, we succeeded and reinstalled the tube into the printer after a an hour or two of heating!

After explaining the different material types, Natalia gave me a more detailed tour of the lab. One interesting contraption is the extruder that creates printable materials. Normally, a spool of material of a specified diameter (1.95 or 2.85 mm) is used for material extrusion printing (see the provided image for reference). However, manufactures may not produce materials that come in spools; rather, they come in pellet form. This extruder machine converts these pellets into a usable spool of printing material by melting the material and reforming it into a thread. It’s a shame, however, that the machine is currently broken since the extrusion tip is clogged. The lab members are working on fixing it, but they have no idea what is wrong after multiple attempts to follow standard protocol. In theory, the machine is highly useful for producing spools of important materials that you can’t buy of the shelf in spool form.

Throughout the lab, there are also other components that need fixing. We looked at the Lulzbot, a material extrusion printer with a twist; it has a flexistrude tip that allows for more accurate extrusion since the motor that moves the spool is closer to the tip. On this contraption, Natalia and I worked on fixing one of the resistors that heats up the nozzle, as well as the temperature indicator on the device. Meanwhile, we printed a cylinder of PCU on a second Lulzbot; this cylinder will later be cut with the laser cutter into a dog bone for mechanical testing, similar to what I did on Friday with Will. After a failed attempt and some more troubleshooting, the print was on its way to be done! One fun fact about material extrusion printing that we took into account while printing the cylinders is: a skirt (small ring around object) is required to help with inconsistencies in the extrusion and may also provide support for the structure.

Overall, today was a fun and educational day! Natalia was very friendly and explained the project well – I hope I can learn even more from her tomorrow. Hopefully the last day will be the best one yet!

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Day 6 – Finishing Our Print Jobs

Today at Chesterfield, Brian and I continued to refine our Cary Academy charger horse print before sending it to the carbon printer. The print itself only took about 15 minutes since the job was so short; however, something went awry! Turns out that the models we printed were too thin and did not have enough integrity to stay intact. That, on top of the fact that the ring hole was too big, caused the structure to fracture. So, we went back to the computer and refined the design so it would be thicker and the hole would be smaller. After a lengthy cleanup process, getting the resin off of the products, the new pieces were finally ready to be put into the oven. Brian proceeded to print out more of his reservoir designs since some of the ones from yesterday warped in the oven and did not function properly today. After about an hour, the new reservoir print was complete. Yet another small mishap occurred: one of the tubes in the half moon reservoirs was broken and rendered the entire model to be experimentally useless. Unfortunately, we had to toss those and were only left with three working reservoirs. We cleaned and cleaned until all the resin was sucked out using isopropyl alcohol and a syringe. All the products were put in the oven at the end and we will return back tomorrow to pick them up.

The past two days have been short, giving me some extra time to reflect upon my experience thus far. With only two days left, I am beginning to access the general conclusions I have made regarding the WEP. I never thought this program would have such an effect on my potential career interest. Coming out of junior year, I already knew that I was more of a STEM person and leaned toward engineering. Having taken Advanced Chemistry, chemical engineering and materials science were definitely up for consideration, but my WEP at Duke has truly helped develop my knowledge and further my interests. Dr. Gall’s lab is rather unique since it is a crossroads between mechanical engineering and materials sciences. I have limited knowledge in regards to mechanics and therefore remain apprehensive, yet mixing it in with something I am familiar with (chemistry) gives me an easy opportunity to further explore my potential interests in the two. Additionally, I am in awe of Dr. Gall’s lab particularly because of the drive each student has to achieve success. Dr. Gall is rather entrepreneurial based, meaning all his research goes to creating legitimate products that help people and not just publishing papers. All of these things intrigue me. Dr. Gall’s research compels me to consider the broader spectrum, because there are in fact multiple realms of engineering that share a common goal: to develop applications that further the state of humankind. Ultimately, working in this lab has given me just a glimpse at how far my passion truly extends to.

Charger Horse Keychains (Two Different Batches)

Day 5 – Carbon Printing Fun

After a traffic-packed morning on I-40, I made it back to Chesterfield for another day of fun and adventure! Today, I worked with Brian, a PHD student working to create orthopedic applications. The issue Brian is trying to tackle involves patients that have deteriorated knee joints that require fillers to help their mobility. Often times, the surgery required to install these fillers will lead to bacteria-caused infections, complicating the process and potentially requiring extra-procedures that might damage the patient’s health even more. Once more, there are not many effective methods to apply antibiotics to these infections once the surgeries are complete. Thus, Brian is developing a specially designed reservoir containing antibiotics that is to be put within the bone implants to combat potential infections. Antibiotics are either stored in a paste or a hydrogel inside of the reservoir. The goal of the project is to create a reservoir which will be easily implemented into the fillers, but also to have an extended amount of extrusion time. After a surgery, the reservoir is intended to constantly extrude antibiotics from the paste to the patient’s blood for a period of over 90 days. In order to achieve an extrusion process for such a long time, the reservoir must be carefully designed to let out small amounts of antibiotics over a large period of time. Brian is studying the numerous amounts of designs up for consideration.

Essentially, the design is a half moon shape since that will most easily fit into the knee filler’s open space. Current knee fillers are made of a bone cement material that is not particularly strong, so Brian is making his filler prototypes with a stronger material, RPU 60, a polyurethane. Some of the reservoir prototypes are also being made in the form of cubes for easier testing. As depicted in the images, each of these reservoirs has a holes, or channels, in the walls so that antibiotic paste can disperse into surrounding liquid overtime. The diameter, length, and orientation of these channels are the main factors being tested. As you can see in the image with the half moon samples, there are tiny channels on the walls where the antibiotics can escape. These holes may also connect to tubes that extend into the reservoir. The length of these tubes is a strong factor that affects the time it takes for all the antibiotic paste to disperse into surrounding liquid. The longer the time, the better. Brian has already made hundreds of different reservoir samples using a carbon printer in the lab, and has tested reservoir samples for antibiotic concentration, obtaining massive collections of useful data. One of his designs has exceeded the expected 90 day requirement and reached a 105-day span until all the antibiotics were extruded into surrounding liquid!

Brian creates all of the reservoir samples using a carbon printer: a sophisticated machine that prints using resin and a UV light. This machine even has a foot-motion activated door! First, the desired compound is ejected using a gun into a beaker. The RPU 60 material that Brian uses contains two components that need to be mixed thoroughly before printing. The gun’s tip helps to mix them well. As depicted in the image below, the gun’s nozzle has a long spiral design that receives two separate substances but quickly mixes them thoroughly. After the required amount of resin is extruded from the bottle (77 mL in this print), it is poured into a clear bed in the printer. The door closes, and a platform lowers into the bed to touch it. The technology behind the print lies in the UV light. As UV light shines underneath the bed, any resin exposed to the UV light will solidify. The plate above helps to create a mask above any resin that is not to be solidified. Layer by layer, the plate raises by only a few millimeters per hour to create the print. Each a layer receives a unique mask that will cover parts that don’t need to be solidified and expose parts that do. After about 2 hours, our print was successfully made to an extremely high precision quality. Today, we printed two more unique reservoir designs, a funnel used to aid in pouring the powder into vials to make the antibiotic paste, and a stirring rod. Brian designs all his prints using AutoCad, a highly sophisticated program that allows for extremely precise creations that can take hours upon hours to design.

The finished products were quite a sight! They were stuck to the top plate, as usual, but the carbon printer has some quirky characteristics, one being that a lot of the original resin is stuck to the products. The resin is highly viscous and is a slight pain to clean up. Nevertheless, there are certain cleanup procedures that make the process a little easier. First, the items are pried off of the top plate and placed in a tub of isopropyl alcohol (2-proponal) and shaken until the viscous resin gets off of the solid products. At the same time, the clear tub and top plate are both cleaned out with isopropyl alcohol and acetone is used to wipe down the clear tub’s glass. Though messy, the cleanup process is crucial to ensuring that the finished products set properly and that the printer’s parts can be reused for future prints. To clean the hollow cubes thoroughly, a syringe is used to pump isopropyl alcohol in and out of the small channels to ensure a resin-free product. After everything is sparkling clean, the products are placed in an oven set at 120 *C for 4 hours to allow the material to achieve its highest potential in terms of its structural properties.

In the afternoon, Brian and I designed a Cary Academy charger horse keychain on AutoCad, and we plan to print it out tomorrow using the carbon printer! After much troubleshooting, the design turned out fairly pleasing. Although today was a short day, I learned substantial knowledge about the different medical applications 3D printers can truly bring forth. With all the advanced technology Chesterfield Lab has, there are an endless amount of possibilities for the devices one can create. The sky is truly the limit on this one!

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Day 4 – Projects Galore!

Back at Chesterfield today! Even though it’s Friday, everyone in the lab was working as hard as ever. Will and I started off the morning with a jam-packed session of activity as he explained to me the three main projects he is working on this summer. His first and most prominent project is working with PVA (Polyvinyl alcohol) a soft but sturdy material that has a widespread array of applications. He is currently developing a PVA material to be used in patients with arthritis, specifically with repairs in the joint between the toe and the foot. Overtime, the cartilage in these joints deteriorates, so Will is trying to develop a self-healing material that can act as cartilage for patients. The self-healing properties are extremely important because patients shouldn’t have to obtain replacement fixes again and again. The material is made of PVA, water, and melamine, a nitrogen-rich material used to strengthen the PVA through hydrogen bonding. The PVA samples are made by mixing solid PVA powder and water in a flask that’s placed in a hot oil bath. Overtime, the PVA will dissolve and turn the liquid into an amorphous structure.

The second project we dove into was the use of hydrogels. Will is helping Shelley Huang, a famous breast cancer surgeon and author, develop an injectable biomaterial for breast cancer tumor resection. The goal is to create a colored material that can be injected into the patient’s tissue while retaining its shape around the tumor so surgeons can more easily locate the tumor before surgical operations. In the lab, we tested this theory by injecting an arbitrary facial cream into a matrix of polyethylene glycol and seeing if it would hold its shape. (Refer to the photos for more detail). The polyethylene glycol (yellow jello-like substance) mimics a patients tissue and the facial cream acts as the injectable biomaterial. Ultimately, if it can be proven that something as generic as the facial cream can be injected while retaining its shape, commonly produced creams or gels can be dyed and up for consideration to use to enhance this medical procedure.

It was brought to my attention today that Dr. Ken Gall, the head professor of this lab, owns a startup company known for developing a new material called polycarbonate urethane (PCU). The plastic-like material is slightly malleable yet substantial, so it retains its shape well. Most importantly, it can be 3D printed easily. The astonishing thing is that few materials with the malleability and durability of PCU can be 3D printed on a mass scale. Dr. Gall is using this creation to develop tracheal support structures for patients that may need implants in their throats to breathe properly. The intrinsic qualities of PCU makes it a good material for this application because it will work effectively, last long, and its dimensions can be tailored for each respective patient. Furthermore, the use of such support structures is far more efficacious than simply cutting a hole in a patient’s trachea so they can breathe – it is a viable and cost-effective solution. In the lab, Will is currently testing the PCU using a laser cutters to determine its true durability, but there are already several cases at Duke Hospital in which the PCU tracheal support structures are up for consideration to be used!

In the afternoon, we carried out tests for each of the three projects. For project one, we poured the batch of PVA that will had prepared into dog bone molds so they could be frozen later for testing. For project two, we checked on the test tube we had injected with facial cream earlier to see how it retained its shape; it did fairly well. Finally, for project three, we spent a few hours at the laser cutter making dog bone samples of the PCU. This was hands down the most enjoyable part of the day since I single-handedly cut two dog bones with the laser cutter by myself! I have never worked with a machine so powerful and was happy that Will gave me the opportunity to do so. The dog bones I cut are going to be used for future strength testing to see just how viable PCU will be as a tracheal support material.

Today was a short, but fun day. Looking back at this week, I have come a long way. I have learned about countless test procedures and several unparalleled projects that immediately captivated my interest. Lab work is definitely where a part of my passion lies, yet I am thankful for the weekend to come so I can take a quick break before going back to Chesterfield on Monday.

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Day 3 – Some Hardcore Testing!

This morning was especially exciting; I got to visit several different labs on Duke’s West Campus. Cambre, a graduate student from Atlanta currently studying at Duke, explained to me in detail each of the steps we took today towards a bigger picture. In the morning, we focused mainly on tensile testing, a process by which samples are pulled apart with a significant amount of force until they break. Of course, very detailed data was collected throughout the process. As you can see in the images, the hydraulic press we used for the tensile testing was rather substantial. Each of the silver clamps depicted weighs 50 pounds, and the grip holding each end of the sample exerts 10,000 Newtons of force onto the sample to prevent it from slipping. That’s right, 10,000 Newtons of force! The test is done by moving the upper grip up ever so slightly over time (fractions of a millimeter per second). As the distance between the clamps increases, the force exerted on the sample increases. That way, when it breaks the machine won’t shoot straight up since the top grip is only set to move up at an infinitesimal rate per second that nonetheless makes all the difference. The whole procedure was recorded by a professional camera called an extensometer, which has the ability to measure precision to the ten-thousandth of a millimeter. This helped to document the total displacement of the sample when tensile tested (how much it “stretched”). Unfortunately, I was not able to operate the extremely dangerous machine, but I did get to tape some broken samples back up together for later use!

Cambre also explained the specific shape choice of the samples. As you can see, the titanium alloy samples are made in a dog bone shape, and this is done for multiple reasons. First, the two ends are paddle shaped in order to be easily gripped by testing machines. Second, the middle, or the “gauge” is thinner so that when the samples are tested, all the force is concentrated into that area, forcing it break in that area and not anywhere else on the bone. The connection between the gauge and the paddle is also tapered to prevent any right-angled corners from being a stress absorption point during testing. In the lab today, we tested samples with solid gauges and those with a funky design in the middle called a gyro. The gyros provided a slightly porous gauge section and varied in wall thickness, from 0.25 mm, 0.5 mm and 1.0 mm. We found that the solid filled gauge dog bones required over 10,000 Newtons of pull to break, while those with 0.25 mm thick gyros only required a little over 2000 Newtons to break.

The whole reason for testing all of these seemingly plain dog bones is because we wanted to determine the quality of the laser titanium printer used to create the dog bones. That’s right, Duke has a 3D printer that literally prints titanium! I was lucky enough to take a peek at it after it was just cleaned, so I didn’t have to wear all the extensive safety equipment required to operate the machine. The 3D printing of the titanium is done through powderbed fusion, whereby an extremely thin layer of titanium powder is placed on a building plate in an inert atmosphere (filled with argon), and a laser melts the powder so it can solidify and reform into the desired shape. A sample can take up to 5 days to print depending on its complexity. Today, we were testing the reproducibility, or in simpler terms, the precision of the laser at different portions of the build plate. The laser in the printer is stationary, so when it shoots to a corner of the build plate, some of the energy may be lost when compared to shooting directly done because the distance the laser has to travel is increased. The tensile testing will determine whether or not samples printed at the corner of the build plate and at the center have any quality difference in terms of their strengths.

After Cambre analyzes the data we collected yesterday and determines how the laser’s distance affects the quality of the print, she will move on the printing more useful applications that can be used in medical procedures! She explained how the gyro shape used in some of the dog bones is actually crucial in the medical field because of its design and can be used in potentially many new applications.

In addition to our time spent in the compression lab, we also visited the Pratt Student Shop, a machinery-filled space for engineering students to complete their projects. Cambre happened to be mentoring an undergraduate student and dropped by in the shop to see how things were going. She showed me an extremely powerful machine called a EDM (Electrical Discharge Machine). This $200,000 gargantuan machine took up over half the room, all for the purpose of cutting materials with a thin wire using electrical discharge. Of course, it can cut metals of various strengths, and this is all done while submerged underwater. The student shop also had other massive tools, including several table saws, laser cutters, and rotary cutters.

Overall, today was a bit repetitive, but nonetheless, I learned much more about the mechanical side of engineering. I appreciated the amount of detail Cambre went into explaining the project and learned just how intricate testing can be. I am looking forward to another day at Chesterfield tomorrow, as I will be working with a new graduate student, Will!

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Day 2 – New and Old Creations

Today, I woke up excited to pay another visit to Suite 420 at the Chesterfield Lab in Durham, working on refining yesterday’s project and exploring a new realm of creation. In the morning, Dr. Kirillova and I worked with 3D printing expert Rex; he explained the fundamentals of using a rather sophisticated software to 3D print a model that Dr. Kirillova had in mind. Rex clarified that there are many careful considerations when choosing settings to 3D print a model! These include factors like the material used (PLA, polylactic acid, or PVA, polyvinyl alcohol), the nozzle and Printcore used, the temperature of the Printcore, and the speed at which the object is filled.

At first, the settings we had used to print the object did not make the printer happy and it wouldn’t complete the job at all. After spending a good hour troubleshooting the machine, we finally got our first model. However, it wasn’t our best model because it lacked an outer perimeter, so the volume percent of the filler was not entirely accurate since the model was not a perfect cube. We tried a second time, adding a perimeter layer so that the object would be more substantial and accurate. Surprisingly, it worked well! After Olivia’s return later in the afternoon, we all printed several more models. Dr. Kirillova also brought to my attention that there are several other types of 3D printing used for different applications. Today, we used one called fuse deposition, whereby solid material is melted to print the new models. Other techniques include carbon printing, titanium printing, printing that uses liquid resin, and even bioprinting, whereby living cells are printed in hydrogels!

The purpose of the print today was to combine it with the bone adhesive to test its structural durability. In other words, the PGLA fiber filler that I mentioned yesterday is similar to the PLA (Polylactic Acid) material used today to print the models. We printed porous cubes of different designs, all 28% PLA and 72% open space by volume, so that tetranite could later be applied inside the open spaces within the cube and solidify to create a strong structure. The PLA housing acts almost like a scaffold for the tetranite. These filled cubes can later be strength tested to see how much the PLA structure will help reinforce the brittle tetranite. In theory, these PLA cubes (or those of other shapes) can be used alongside the tetranite to create the most durable, efficient, and biodegradable solution to help mend broken bones together inside bodies! More complex bone repairs will of course require more durability relative to the size of the combination used. Lucky for us, PLA is a biodegradable material despite its plastic-like appearance.

In the afternoon, Olivia and I polished the bone adhesive samples we made yesterday (her titanium and my salt sample). The process consists of placing the cylindrical sample in a mold that will hold it in place while it is sanded against fine sandpaper with water. This helps to smoothen the top and bottom surfaces of the cylinder, so when it undergoes compression testing later, the data collected will be more accurate. In addition, we measured the lengths and widths of the polished samples with a caliper, something I had actually never used before this day! Olivia’s titanium samples were quite easy to polish, and they even gave off a nice shine after they were completed. My salt samples, however, proved to be more brittle, so I was only able to successfully polish two of my four original samples. Nevertheless, I am thankful that I was granted permission to collect my samples and one of the 3D printed models today to bring home; they will serve as a lasting souvenir of an incredibly captivating project!

Tomorrow, I am assigned to work in a compression lab to witness some of the actual strength tests that are performed on the polished bone adhesive samples. This lab will be on Duke’s campus, so I am eager to take the next step of this invigorating journey in a fresh environment!

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Day 1 – Creating Bone Adhesive Samples

This afternoon, I began my Work Experience Program at Dr. Ken Gall’s lab in the Chesterfield at downtown Durham (a Duke labspace). After receiving a short tour of the lab space from a friendly student, I met with the supervisor Dr. Kirillova and Olivia, one of the undergraduate students working in the lab, and we discussed the specific project they are currently working on. Dr. Kirillova is working with another startup, Launchpad Medical LLC,  to create a bioresorbable bone adhesive that can ideally be used efficiently and effectively with future medical patients that require bone treatment. To my surprise, the creation of such mineral-organic bone adhesive was inspired by the sandcastle worm, an animal that secretes unique fluids that has the power to “glue sand together.” I learned today that the bone adhesive used in the lab is formally known as “tetranite,” a powder made up of tetracalcium phosphate (Ca4O(PO4)2) and O-phospho-L-serine. The adhesive is unique in that its initial powder form turns gooey immediately after contacting water and eventually solidifies into a solid. In theory, the adhesive may be applied in between two broken bones and solidify quickly to hold the bones together. The substance’s strength and porosity can be adjusted based on the porosity of the bone marrow being treated. For example, a cortical bone requires a “uniform layer of adhesive” because it is less porous and a cancellous bone will host an “irregular adhesive that penetrates into pores” due to its higher porosity. Additionally, the bone adhesive is biodegradable, so in theory, the adhesive will extinguish itself overtime within the bone and new bone marrow will form to fully heal the broken bone. In fact, previously conducted research on a rabbit revealed that 75% of original bone tissue reformed in just one year after it was originally broken, using the bone adhesive to mend the broken bones back together.

As I mentioned earlier, the bone adhesive can be modified for different strengths and porosity using “fillers.” (Usually, higher porosity will decrease the strength of the adhesive, so finding the right balance for different applications is crucial to the use of these adhesives). The three main fillers I learned about were NaCl, fibers, and powdered titanium, which we tested today in the lab for the first time! Generally, adhesives with added NaCl demonstrate higher porosity and that with added fibers yields higher strength; the titanium has yet to provide conclusions. Today, I learned how the samples of bone adhesives with added fillers are made in the lab prior to being tested for strength and porosity. Olivia prepared samples with added titanium powder, and I had to exciting opportunity to prepare samples with added NaCl.

The process by which the sample is made is quite interesting. I was provided with the luxury of using a pre-made mixture of tetranite and NaCl, but in theory I would have first calculated the right amounts of each separate powder and mixed them together. After massing out the correct amount of the combined powder into a small mixing apparatus, I ensured that the powders were mixed homogeneously to create the most accurate sample. I then pipetted 405 microliters of deionized water into the mixer and quickly mixed the water in before the bone adhesive started to solidify. The immediate reaction between the powder and the water really surprised me at first! To create a sample of a specific shape and size, I put the new gooey substance into a syringe and excreted it into a small cylindrical mold, scraping off the top edges for excess material in order to ensure a smooth sample. The substance fully solidified after about 15 minutes, and I used a drill bit to pop it out of the mold and put it in a phosphate buffered saline. This vial was placed in a warm water bath at  37*C (close to body temperature), and we plan to polish the samples after they sit in the water for another 48 hours. The solid samples will be strength tested in order to predict their strength performance in real-world applications, like when inside patients’ bones.

I am happy to say that my first day at the Chesterfield lab was an exciting and rewarding one. I was delighted to be given the wonderful opportunity to actually create some samples myself! At first, I was a bit apprehensive of my abilities to create a sample that would match the quality of the ones Olivia made. Yet, after about three tries, I can confidently say that I made a sample that was much better than what I had expected. After spending less than four hours in the lab today, I left feeling that I had accomplished something substantial and learned about a project that truly intrigued me. Overall, the state-of-the-art lab equipment in Suite 420 was more impressive than anything I have ever laid my eyes on, and I cannot wait for another day of learning at the lab tomorrow!

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