Modern Westernized medicine is constantly developing novel clinical and surgical practices. These practices have been created in response to rapid advancements in technology and society’s desire for better, faster and more reliable treatments. The current need for reliable clinical practices has created a relatively new discipline known as bioengineering (Griffith, 2001). Bioengineering incorporates molecular and genomic medicine, material sciences and modern technology to create novel clinical practices.
Biological engineers have successfully created skin, bladder, bone, liver and kidney cells out of animal or human stem cells (Griffith, 2001; Solchaga, Penick and Welter, 2011). However, one of the most researched and successfully manufactured cells are cartilage cells, also called chondrocytes. Typically, chondrocytes are grown from stem cells on scaffolds comprised of collagen hydrogels and interlocking nanofibers (de Moraes, et al., 2012). Scaffolds are three-dimensional templates designed both to support these cells and provide a location for extracellular matrices (ECM) to grow. ECMs are made of different proteins and polysaccharides that aid in maintaining cellular homeostasis and functions (Alberts, Johnson and Lewis, 2002). As the ECM grows, the scaffold degrades so the cells can thrive independently in the three-dimensional shape of the initial scaffold (Kisiday et al., 2002).
Arguably, the material chosen to create the scaffold is one of the most important aspects of growing artificial tissues. Scaffolds need to be biocompatible with chondrocytes and not degrade into harmful compounds, that can damage new and native cells (Kisiday et al., 2002). Scaffolds are commonly made of peptide-based biomaterials that can self-assemble into stable hydrogels. Peptides such as KLD-12 (Figure 1) and EAK12 have traditionally been used to grow chondrocytes (Kisiday et al., 2002; Zhang, Holmes, Lockshin and Rich, 1993). These particular peptides, and other similar peptides, have been used to create successful scaffolds due to their unique characteristics such as charged amino sequences, hydrophobicity and hydrophilicity. For instance, KLD-12 has alternating hydrophobic and hydrophilic side chains (Kisiday et al., 2002). When an amino acid sequence has alternating hydrophobic and hydrophilic side chains, the resulting peptide has β-sheet geometry (Zhang et al., 1993). The charges can be considered one driving force for the self-assembly of β-sheet structures within these peptides (Kisiday et al., 2002). Once the β-sheet structures are formed, the peptides are dissolved in an electrolyte solution, which causes them to intertwine into nanofibers.
Once the scaffold is made, the stem cells are casted onto the scaffolds and are left to grow for up to 30 days (Kisiday et al., 2002). After the cells mature, they are inserted into the bed of an open wound to grow with the damaged host cells. Once inserted, the cells amalgamate with the host cells and close the wound. This treatment has only been tested on animals, yielding satisfactory results. Even though this technology is not used in modern clinical practice, research in this field can provide hope that one day Westernized medicine will be able to rely on stem cells to save victims of severe wounds, burns and skin diseases. As medicine continues to advance, new fields such as bioengineering are created allowing for research in what can be considered futuristic medicine to develop and potentially prosper.
Works Cited:
Alberts, B., Johnson, A. and Lewis, J., 2002. Molecular Biology of the Cell. 4th ed. New York: Garland Science, p.1104.
Griffith, L.G., 2001. Advances in Biomedical Engineering. JAMA, [online] 285(5), p.556. 10.1001/jama.285.5.556 [Accessed 18 Sep. 2014].
Kisiday, J., Jin, M., Kurz, B., Hung, H., Semino, C., Zhang, S. and Grodzinsky, A.J., 2002. Self-assembling peptide hydrogel fosters chondrocyte extracellular matrix production and cell division: implications for cartilage tissue repair. Proceedings of the National Academy of Sciences of the United States of America, [online] 99(15), pp.9996–10001. 10.1073/pnas.142309999 [Accessed 18 Sep. 2014].
De Moraes, M.A., Paternotte, E., Mantovani, D. and Beppu, M.M., 2012. Mechanical and biological performances of new scaffolds made of collagen hydrogels and fibroin microfibers for vascular tissue engineering. Macromolecular bioscience, [online] 12(9), pp.1253–64. 10.1002/mabi.201200060 [Accessed 22 Sep. 2014].
Solchaga, L.A., Penick, K.J. and Welter, J.F., 2011. Chondrogenic differentiation of bone marrow-derived mesenchymal stem cells: tips and tricks. Methods in molecular biology (Clifton, N.J.), [online] 698, pp.253–78. Available at: 10.1007/978-1-60761-999-4_20 [Accessed 9 Sep. 2014].
Zhang, S., Holmes, T., Lockshin, C. and Rich, A., 1993. Spontaneous assembly of a self-complementary oligopeptide to form a stable macroscopic membrane. Proceedings of the National Academy of Sciences of the United States of America, [online] 90(8), pp.3334–8. Available at: 7682699 [Accessed 23 Sep. 2014].
Comments
7 Responses to “Amino Acids: a Scaffold to a Better Future”
Hey guys! I decided to write this blog post because it covered some of the biochemistry we looked at in first year and in my biochem 2L06 course now. This post has elements of biochemistry, materials science, engineering and biology. This relates to current topics in iSci for me as a second year student since we have discussed cell bio in neurosciences and talked briefly about protein structure relating to function. I hope you enjoy reading it and comment on it so I can have a great final product.
Thank you and enjoy!
– Dakota
Great post Dakota!
Every time you introduced a new term or idea it was very well explained. This created good flow and made a very complex topic relatively easy to understand. Although there is currently little application in human medicine the potential of this concept is fantastic and it is very interesting to learn the specifics behind the technique. My only suggestion would be to make the introduction paragraph a bit more specific as the topic is quite specific and the introduction is in comparison a little vague.
Really enjoyed this!
Lindsey
Hey Dakota (aka superstar),
FIRST OF ALL, your title was amazing and really intrigued me to read the post! So kudos on that! Here are some little suggestions.
1) I don’t think westernized medicine in your first paragraph needs a capital. I’m not too sure, I just didn’t think it was necessary.
2) I would consider rewording the sentence “Scaffolds need to be biocompatible with chondrocytes and not degrade into harmful compounds so as to minimize damage to both new and native cells” It was a little awkward. Maybe change it to “…..not degrade into harmful compounds, that can damage new and native cells”
3) The sentence “The charges can be considered one driving force for the self-assembly of β-sheet structures with these peptides” should be within not with maybe?
Also that image was a great addition to your post and really provided a nice visual! Great job!
HAVE FUN EDITING,
YOUR BIG SIB 🙂
Amazing blogpost Dakota!
I remember doing a similar blogpost talking about how fingers can be completely regenerated using extracellular matrix. The substance they use is Matristem. You may want to look into it for further insight!
Some improvements I would recommend is to talk a little more about ECMs. I am not well versed on this topic anymore but I believe ECM’s create some sort of field that aids with the regeneration of cells and cannot be overlooked. You may want to look more into this if you have space. Also some general information about ECMs would be helpful as “maintaining cellular homeostasis” is a bit vague.
Another recommendation would be to omit unnecessary information to leave space for more depth in other parts. For example “These nanofibers are three orders of magnitude smaller than most known nanofibers.” As you do not supplement the text by identifying the significance of this smaller magnitude and neither is it helping to get your main message across, it seems unnecessary.
Overall, I found this blogpost very informative and more importantly, easy to follow and comprehend. I didn’t have to reread it to make sense of what you were saying but rather to help myself make a vivid picture. Props for that.
Nafis Wazed 🙂
Hi Dakota,
I enjoyed reading your post! It was informative and had a logical flow, making it easy to understand. As others have mentioned, you used the image of KLD-12 very effectively.
Just some recommendations:
– In the first paragraph, you might want to try saying either “The current dependency” or “The current need”, since I don’t think both are necessary.
– When talking about KLD-12, you can try combining the two sentences that discuss “alternating hydrophobic and hydrophilic side chains” to avoid the repetition.
– Similarly, your first three sentences start with “once” in the final paragraph, so consider changing at least one of the transitions to make it easier on the reader. Also, this paragraph does not flow as well as your others. In the paragraph before, you were talking about scaffolds, then peptides, but then included some seemingly tangential information at the end of the paragraph. I could be wrong, though, so if it is important to include, just make sure it flows into your final paragraph.
– I found this sentence a bit ambiguous: “This treatment has only been used on animals with satisfactory results”. I think you mean that the treatment has only been tested on animals, as opposed to humans, and all those trials showed satisfactory results. However, the sentence could also suggest that the treatment has been tested on both animals and humans, but only the animal trials produced satisfactory results.
Other than that, your post was very well done, and I look forward to reading your final version!
Devora
Hi guys thanks for the comments. I am going to address each one by person.
Lindsey
– Thank you I was hoping that I was able to make this topic simple, but not too simple
– I ended up changing my conclusion which I think will make the introduction make more sense. I am starting off broad, getting very detailed then bringing the post back broad and back to being about Westernized medicine
Vince (best big sib ever)
– I changed the wording that you suggested. I think it flows much better now
– In most of the literature I looked into Westernized was capitalized so I think it should be fine. I also made sure I capitalized it every time to ensure consistency
Nafis
– I got rid of the information about the nanofibers like you suggested. I just thought it was such an interesting fact haha, but you were right, it was not needed nor enhanced my writing
– I am not going to expand on the ECM for two reasons:
1. I would be way over the word count
2. I think that it is so complicated that if I did get into it, it would make my post more confusing and take away from the points I am trying to make about scaffolds
Devora
– I made the changes you suggested in the first and last paragraph
– I hope I have made them flow better and relate to one another better as well. I think changing my last sentence was also a good idea and aids in the flow of my post
– I made the clarification you also suggested regarding animal testing
– I however did not change the sentences about the “alternating hydrophobic and hydrophilic side chains” because how ever I re-worded it it sounded awkward. I hope it is not too confusing left how it is
Thank you all for the comments, they definitely improved my post!
– Dakota
Dakota,
I think the change in the conclusion makes the overall flow much better and I get where you are coming with by starting very general it just sometimes seems unrelated.
Really like the revisions!
Lindsey