GUM GUM: Recent Research Produces Rubbery Material to Replace Human Tissue

“GUM GUM BAZOOKA!” (Eiichiro, 1999) the protagonist of hit anime One Piece, Monkey D. Luffy, howls to deliver the finishing blow on his enemy.

As watchers of the acclaimed series know, Luffy’s power is that of the gum-gum fruit, which makes his body act as rubber. This seems like something only to happen in an anime, and while it is likely best that rubber bones stay relegated to that fictional, animated world, recent nanostructures and materials research could provide humans with a multipurpose, synthetic, rubbery substance that works in accordance with the human body. At Chalmers University of Technology in Sweden, researchers in the chemistry, chemical engineering, and applied physics departments have discovered a rubbery substance that has the potential to replace human tissue (Rajasekhara et al., 2019). 

In order to create an synthetic elastomer (material of a solid state but with relatively high amounts of elasticity) that could agree with the human body, scientists rethought the process of making elastomers. Previously, researchers made elastomers by randomly linking polymers - materials created by the linking of macromolecules - together. To create elastomers that are compatible with the human body, they sought a more organized approach. This new elastomer would be used as synthetic tissue, so its creators used a technique called ordered structuring to connect polymers with collagen and elastin, two fibrous proteins prominent in human skin (Rajasekhara et al., 2019).

With the help of state-of-the-art nanostructuring technologies, ordered structuring now makes the creation of elastomeric substances possible. This allows the surface to be lined by a material (namely what would be in contact with organs) with antibacterial peptides, making the elastomer resistant to bacteria so that it will not be damaged by the natural bacteria present in humans. One of the current applications for this elastomer involves catheter tubes. The material is able to carry medicine or blood while remaining decontaminated and also not killing the bacteria. This is helpful because there is an increasing trend of bacteria becoming antibiotic resistant , so it is becoming harder to eliminate them (“Nanostructured rubber-like material…”, 2020). This synthetic elastomer tube does not result in bacteria death, rather bacteria removal.

Beyond bacterial resistance, the elastomer has a variety of unique properties. Its soft and elastic nature means that it can be injected into the body by a cannula or 3D printed into a specific shape, and its nanopores can be filled with medicine to allow the synthetic tissue to cater to patients’ specific needs (“Nanostructured rubber-like material…”, 2020).

In theory, these biological elastomeric tissues could be used to create a being with rubbery bones. But, let's leave the gum-gum fruit abilities to Luffy and appreciate the material for its potential to revolutionize medicine.

References:

Eiichiro, O. (Oda), & Konosuke, U. (Uda). One Piece. Toei Animation.

Nanostructured rubber-like material with optimal properties could replace human tissue. (n.d.). ScienceDaily. https://www.sciencedaily.com/releases/2020/03/200316090334.html 
Rajasekharan, A. K., Gyllensten, C., Blomstrand, E., Liebi, M., & Andersson, M. (2019). Tough Ordered Mesoporous Elastomeric Biomaterials Formed at Ambient Conditions. ACS Nano, 14(1), 241–254. https://doi.org/10.1021/acsnano.9b01924

Attacking Cancer: A Golden Opportunity

You don’t have to be a historian to grasp the significant impact gold has made in the world. From a sought-out treasure to a method of currency, there’s no doubt that this element is one of the most influential metals in human history. Yet, a much less known aspect of gold is its incredible potential in biomedicine. This is especially true of gold nanoparticles in the context of cancer.

Cancer is a condition wherein cells proliferate and divide in an uncontrolled manner. [1] While cancer can often be treated, the side effects of those treatments can be severe and can include possibly hurting non-cancer cells and the immune system. Inducing hyperthermia, or causing a part of the body to heat up, has been shown to have an anticancer potential as it can lead to programmed cell death as well as make tumors more susceptible to radiotherapy. Yet, a central issue arises: unless the heat is localized, other parts of the body can be harmed. This is where gold nanoparticles come in. [2]

In the simplest terms, gold nanoparticles are small pieces of gold. Very small pieces of gold. As a result, gold nanoparticles have a lot of different properties compared to, say, a block of gold that we often think about when talking about the element. For instance, gold nanoparticles are not yellow: particles less than 100 nm are red while bigger particles are blue/purple. [3] These nanoparticles have amazing properties which allow them to act as a contrast in CT scans or assist with drug delivery. [4] Yet, one of the most fascinating applications of these gold nanoparticles is their use in photothermal therapy. Because the blood vessels near the tumor site are often leaky, gold nanoparticles that have been placed in a cancer patient's body will passively concentrate near a tumor. Once they have concentrated, they can be activated by near-infrared light, a special type of light which can easily pass through human tissues. The gold nanoparticles will absorb the light energy and convert it to heat energy near the tumor, essentially stimulating the cancer cells’ deaths. [2]

Has this technique been tested in humans? In fact, yes–a clinical trial done at Mt. Sinai hospital which used gold-silica nanoparticles to treat prostate cancer patients revealed no severe side effects from the treatment. After the gold nanoparticles had concentrated at the tumor site of the patients, they were irradiated by near-infrared light from optical fibers. These nanoparticles absorbed the light and heated the tumor site, essentially destroying it. [5]

The promise of such a localized treatment strategy is encouraging. Hopefully, further research can be done to explore this opportunity that is, indeed, worth its weight in gold.

References

[1] Gupta, N.; Malviya, R. Understanding and advancement in gold nanoparticle targeted photothermal therapy of cancer. Biochimica et Biophysica Acta (BBA) - Reviews on Cancer [Online] 2021. 1875, 188532. https://www.sciencedirect.com/science/article/pii/S0304419X21000305?via%3Dihub (accessed November 2021)

[2] Vines, J.B.; Yoon, J.-H.; Ryu, N.-E.; Lim, D.-J.; Park, H. Gold nanoparticles for photothermal cancer therapy. Front. Chem. [Online] 2019. 7, 167. https://www.frontiersin.org/articles/10.3389/fchem.2019.00167/full (accessed November 2021) 

[3] Sztandera, K.; Gorzkiewicz, M.; Klajnert-Maculewicz, B. Gold Nanoparticles in Cancer Treatment. Mol. Pharmaceutics [Online] 2019. 16, 1-23. https://pubs.acs.org/doi/10.1021/acs.molpharmaceut.8b00810 (accessed November 2021)

[4] Wang, S.; Lu, G. Noble and Precious Metals - Properties, Nanoscale Effects and Applications. In Applications of gold nanoparticles in cancer imaging and treatment; Intechopen: Online, 2017.

[5] Stephens, M. PhysicsWorld. https://physicsworld.com/a/gold-nanoshell-based-cancer-treatment-is-safe-for-the-clinic/ (accessed November 2021)

[6] Pxfuel. https://p1.pxfuel.com/preview/830/131/627/cancer-cells-cells-scan-electron-microscope-scan.jpg (accessed November 2021)