Intro

In 2021-2022, I developed a novel water-resistant bioplastic concept to be showcased at that year's Dutch Design Week.

I built a lab at Hackspace Manchester and took on the role of researcher to fulfill the project. I successfully produced an MVP (Minimum Viable Product) on time for Dutch Design Week. This is my story.

above synthetic nacre

The brief

Brief was simple: a new biodegradable material intended to replace petrochemical-treated roofing shingles, as it possesses:

Water stability.
Mechanical properties similar to those of wood (specifically, pine).
The ability to be manufactured into a flat sheet.

Lets Build a Lab

Before research can take place, a lab needs to be built. Where better than a little-looked-after corner of the hackerspace? The problem is that there is a hole in the corner that requires a lot of work.

the room needed scaffolding putting up too remove a section duct work that had been placed in the cavity since the building was refurbished.

walls where cleaned floor was sealed, painted and made to look a lot nicer than it was. total area just shy of a shipping container

humble roots

Research started with basic laboratory supplies, taking time to get to work. Most of it was bought second-hand.

Short List Bio-materials

Now, with a laboratory in hand, a starting point was needed, and for that, materials were needed. Four materials were chosen for their physical properties and manufacturing processes. The material from the short list I chose to pursue was a form of mineralized chitosan - a copy ofNacre

SCoBY (Symbiotic Culture of Bacteria and Yeast) leather is a flexible, tough material similar to leather, limited by bio-reactor size. Greatly affected by disturbance on the surface. It does not scale well. The sample was made by Gabriel L.
Paper-based chitosan composites had the strength required, but degraded under water. A sample was made by Gabriel L.
Chitosan hydrogels could be made on a large scale and affordably; however, they lack water stability in their raw form. Modifying its properties is well understood from the literature.
Alginate and mineral alginate cross-linked with calcium chloride. Water-stable, however, too brittle in its current configuration. This sample was prepared by Gabriel L.

Nacre

What is Nacre and why should you care

Natural nacre is a durable composite of Aragonite plates and silk fibroin (1)(2)(3)
Nacre is grown within bi-valves most popular is the Abalon
All members of the Abalone population [4] are in decline due to overfishing
Whilst Synthetic nacre has been reproduced in the lab [1][2][3][6][7] their methods haven’t been observed outside of a lab at scale
Current synthetic nacre relies on unproven manufacture methods. i would like to change this

what makes nacre work

To mimic the Nacre aragonite platelets, needs to be grown in interlocking aligned structure.
Need to promote aragonite growth while inhibiting calcite formation
Directed crystal growth on the a-b-Axis via surface modification of the chitosan with short length peptides. While inhibiting growth on the c-Axis

Nacre making time ( 6 months of barking up the wrong tree)

growing aragonite on cotton

In an early experiment on growing argonite (not "aragonite") cotton, I was finding it difficult to source chitinase (not "chitosan"). These experiments did not work out as expected, because crystals would not adhere to the surface of the fibers.

growing aragonite on chitosan

To grow the crystals on the hydrogel, the film needs to be held down. For this, I made a jig that holds down the film so that it does not curl up.

Results from directed mineralised chitosan films

Following examples from literature, it was possible to grow aragonite outside of a biological system.
Our research into aragonite platelet growth on modified chitosan hydrogels (PMMA) has proven successful. Below, you can see the aragonite crystals are the pointy strands.

Issues with dendritic growth and erratic changes in morphology of the aragonite reduced yields were in the milligrams per litre (mg/L) range, and thus new processes were needed.

lab had grown

results for real this time

A final product was made after changing the protocol, and a series of tests were done to test their suitability. I cannot go into too much detail on what this material is made of or how it's made, but I will show some of the tests below. Below is a sample of the final MVP.=

water test

The samples were cut and placed in water and were observed for a period of one month.

Treated panels were more water stable than untreated panels.
Untreated panels experienced water damage within hours of contact and completely degraded within a month
In contrast, the treated panels showed little to no damage after a week and only a minor color change after a month with no further degradation

non treated samples

treated samples

Displayed at DDW

I had a lot of fun at Dutch Design Week, speaking to a lot of people about biomaterials. Here are some of the pictures from that trip.

the building was shaped like a UFO
and a picture of our table inside

another team had a perfume robot that i helped fix from a overly tight belt and in return i got given some of the robots perfume.

References

[1]E. M. Spiesz et al., “Bacterially Produced, Nacre‐Inspired Composite Materials,” Small, vol. 15, no. 22, p. 1805312, Apr. 2019, doi: https://doi.org/10.1002/smll.201805312.
[2]L.-B. . Mao et al., “Synthetic nacre by predesigned matrix-directed mineralization,” Science, vol. 354, no. 6308, pp. 107–110, Aug. 2016, doi: https://doi.org/10.1126/science.aaf8991.
[3] H.-L. Gao et al., “Mass production of bulk artificial nacre with excellent mechanical properties,” Nature Communications, vol. 8, no. 1, 2017. doi:10.1038/s41467-017-00392-z • [4]NOAA Fisheries, “White Abalone,” NOAA, 2019. https://www.fisheries.noaa.gov/species/white-abalone
[5] (5) “Blue Mussel,” Wikipedia, 23-Sep-2022. Online:. Available: https://en.wikipedia.org/wiki/Blue_mussel#/media/File:Mytilus_edulis_001.jpg. Accessed: 09-Jan-2023:.
[6] (6) E. M. Spiesz, D. T. Schmieden, A. M. Grande, K. Liang, J. Schwiedrzik, F. Natalio, J. Michler, S. J. Garcia, M. E. Aubin‐Tam, and A. S. Meyer, “Bacterially produced, nacre‐inspired composite materials,” Small, vol. 15, no. 22, p. 1805312, 2019.
[7] (7) T. Kato, “Polymer/calcium carbonate layered thin-film composites,” Advanced Materials, vol. 12, no. 20, pp. 1543–1546, 2000. doi:10.1002/1521- 4095(200010)12:20<1543::aid-adma1543>3.0.co;2-p
[8] (8) K. K. Sand, J. D. Rodriguez-Blanco, E. Makovicky, L. G. Benning, and S. L. Stipp, “Crystallization of caco3 in water–alcohol mixtures: Spherulitic growth, polymorph stabilization, and morphology change,” Crystal Growth & Design, vol. 12, no. 2, pp. 842–853, 2011. doi:10.1021/cg2012342