Pollen: An Immediate Solution from Nature
https://doi.org/10.1038/s41467-020-15294-w Transformation of hard pollen into soft matter @ Nature Communications
As a materials scientist, discovering new class of materials is an exciting journey and even translating humble, natural materials into potentially useful applied materials for human life is tremendously rewarding. However, history has also shown that many such findings require waiting for the right time for emerging technological developments to match up with industrial needs. For example, lithium ion battery technology and carbon buckyballs were discovered long ago, but they were not applied to real life until technological progress and societal needs matured to the point of needing such advanced technologies. Now, while we continue to look forward to new synthetic and engineered innovations, we also face unprecedented environmental challenges from non-natural materials like plastics and need to gain inspiration from nature and its miraculous resources.
One exciting example is natural pollen, which is the humble workhorse of plant life that has fascinating material properties. There are many myths associated with pollen. If you hear about pollen, your brain automatically gives you a signal to remind you about “Allergy” or “Allergic Reaction”. However, the material properties of pollen are too good to be abandoned based on this issue alone. Indeed, pollen grains are remarkably useful microcapsules that can be easily transformed into non-allergenic forms and are excellent candidates to build plastic replacements if one can find a way to transform their shape. Pollen grains are microscale capsules that are produced by plants and have unique material properties that make them “practically indestructible”1. The outer coating of pollen shells is composed of sporopollenin, which is considered the diamond of biopolymers. The allergy-causing proteins of pollen can be removed in order to leave the durable sporopollenin shell in the form of a safe, non-allergenic hollow microcapsule. Just as important, pollen is naturally produced by plants in excessively large quantities in order to ensure reproductive success, while the vast majority of pollen grains are left unused. All of these advantageous features and many more make pollen renewably abundant, eco-friendly, safe, and cheap. Towards this goal, we recently developed a very simple method – similar to the basic steps in traditional soapmaking in light of to keep the processing as simple and as cheap as possible – that can transform super-strong pollen grains into soft, flexible building blocks. Using industry manufacturing strategies, these pollen-based building blocks can be easily turned into a wide range of useful materials. The paper herein describes the first example of designing pollen-based building blocks that can be further translated into different classes of materials including sponges, sheets, and polymer gels. Combined with the power of 3D/4D printing, there are nearly limitless options to develop and manufacture natural pollen-based materials that could replace non-natural plastics in the near future.
1 Birks, H. J. B., Birks, H. H. & Ammann, B. The fourth dimension of vegetation. Science 354, 412-413 (2016).