Next generation sustainable materials
At TMIG, we focus on discovering natural materials as sustainable alternatives for current materials. We have pioneered the development of pollen processing to unlock its potential to be a new material for diverse real-world applications.
Be part of the change towards a sustainable future.

What is pollen?

Pollen is a powdery substance produced by the anthers of most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains, which encapsulates male gametes. Every plant species has a unique pollen grain structure, ensuring that plant reproduction is selective by only ensuring plant stigmas only accept pollen grains from compatible sources. Pollen grains have a hard outermost protective layer made up of sporopollenin that protects the genetic material from environmental conditions and as a delivery vehicle during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of gymnosperms. Upon release from the parent plants, pollen become dehydrated and the individual grains fold onto themselves – a structurally intricate process termed “harmomegathy”. Conversely, pollen are able to undergo architectural remodeling during pollen tube growth, initiated by an organized sequence of enzymatically-controlled reactions, which leads to the opening up of the pollen aperture. Biologically, this process is spatially-controlled within the structure of the pollen wall by converting as-synthesized esterified pectin molecules into a de-esterified form.
Picture: Pollen grains have a hollow microcapsule structure, function-driven shape, and ornamental architecture. The hard outermost exine layer is made up of sporopollenin, which is a strong, cross-linked biopolymer that protects the genetic material, while the inner intine layer is composed of elastic, load-bearing cellulose/hemicellulose microfibril network structures and pectin.
What properties of pollen make it attractive for use as a material?
It is worthy to note that the concept of transforming pollen into a valuable commodity to achieve pollen-based materials innovation as a sustainable solution stemmed from the realization of the sheer abundance of raw pollen in nature. Plants produce large quantities of pollen. For example, the maximum yield of Helianthus tuberosus L. is 57.8-212.7 kg/ha during the season of blooming and fully-grown pine trees produce around 200-300 kg/ha in a year (1). While most plants produce enormous quantities of pollen to ensure reproductive success, most ends up as “bio-waste”. Most of these pollen particles can be easily collected from the natural environment through manual sampling or with the aid of a suction pump; most of these methods are already available and used by commercial harvesters (e.g., in bee pollen harvesting for health supplements).
Sustainable
Abundance
Ref: 6abc Philadelphia
The environmental and climate impact of using pollen-based materials is clear. Taking papermaking as an example, the current cellulose-based technologies require cutting down trees and other plants, resulting in significantly negative impact on the environment and the eco-system. Pollen, on the other hand, is intrinsically renewable. They can be collected year after year without detrimental effects on the trees and plants. Pollen-based materials, therefore, are the truly eco-friendly alternative compared to cellulose-based materials.
Robust
Resilience
Ref: Birks, H. J. B., Birks, H. H., & Ammann, B. (2016). The fourth dimension of vegetation. Science, 354(6311), 412-413.
Plant sporoderm is well known for its indestructibility and its long-term spanning millions of years (2). Their size or the aspect ratio will not change even under harsh chemical (such as a variety of hot strong acids and alkalis) and physical conditions (such as under long-time stirring) regardless of its hollow structure or shape.
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Denisow, Tymoszuk & Dmitruk. Nectar and pollen production of Helianthus tuberosus L.–an exotic plant with invasiveness potential. Acta Botanica Croatica 78, 135-141 (2019)
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Birks, Birks & Ammann. The fourth dimension of vegetation. Science 354, 412-413 (2016).
What are specific advantages of pollen as materials compared to other biomaterials (cellulose, lignin, chitin, etc.) that have already been produced in large scale?
Biomaterials are widely used for practical applications, and their raw materials are typically derived from their natural resources through complicated extraction processes. Depending on the processing methods and sources, the properties of raw materials are not always well-controlled. Moreover, after extraction, their powder or liquid forms need to be re-formulated for final products. To extract raw materials from natural resources, the natural systems in most cases need to be sacrificed. An example would be the manufacture of conventional paper, which involves mechanical logging, debarking and chipping of forest trees to produce woodchips, which then are chemically processed into cellulose-based pulp. Subsequent screening, bleaching, and washing are necessary to decolorize the pulp to produce final paper products. Environmental concerns not only arise due to the logging of forest trees, (i.e., leading to increased greenhouse gases in the atmosphere, desertification, and loss of biodiversity, etc.) but also due to the high energy requirements of the multi-step process and harsh chemicals used (1).
On the contrary, pollen is a renewable resource often regarded as ‘bio-waste’, being naturally released into the environment in large quantities. Pollen grains are an established microscale biological system with excellent mechanical properties, chemical stabilities, and biocompatibility. The pollen grain itself can be used as a biomaterial system without breaking it down into its constituent biomolecules. Furthermore, compared to other biomaterials, pollen, due to its complex multifunctional nature, is highly versatile and can be processed into different material forms and transformed into materials with highly tunable properties for different applications. At TMIG, our approach allows pollen grains to become processible as microscale building blocks by transforming the pollen grains into pollen microgels (2). Pollen microgels can be stacked and assembled with strong adhesion between microgels, forming macroscale applications such as films, sheets, sponges, and blocks depending on processing methods (3-6). Furthermore, these processes are simple, scalable, and cost-effective since the starting material, pollen microgels, are highly uniform, micro-scale and measurable, as opposed to other molecular-based biomaterial systems. Due to structural diversity of pollen grains which vary in accordance with their plant species, the properties of pollen microgels can be modulated by selecting pollen from appropriate species and by varying the parameters of the transformation process, thus diversifying the resultant material properties of pollen-based products.

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Zhao, Z.; Deng, J.; Tae, H.; Ibrahim, M. S.; Suresh, S.; Cho, N. Recyclable and Reusable Natural Plant‐Based Paper for Repeated Digital Printing and Unprinting. Adv. Mater. 2022, 34 (19), 2109367.
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Fan, T.-F.; Park, S.; Shi, Q.; Zhang, X.; Liu, Q.; Song, Y.; Chin, H.; Ibrahim, M. S. B.; Mokrzecka, N.; Yang, Y. Transformation of Hard Pollen into Soft Matter. Nat. Commun. 2020, 11 (1), 1449.
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Chen, S.; Shi, Q.; Jang, T.; Ibrahim, M. S. B.; Deng, J.; Ferracci, G.; Tan, W. S.; Cho, N.-J.; Song, J. Engineering Natural Pollen Grains as Multifunctional 3D Printing Materials. Adv. Funct. Mater. 2021, 31 (49), 2106276. https://doi.org/10.1002/adfm.202106276.
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Zhao, Z.; Deng, J.; Tae, H.; Ibrahim, M. S.; Suresh, S.; Cho, N. Recyclable and Reusable Natural Plant‐Based Paper for Repeated Digital Printing and Unprinting. Adv. Mater. 2022, 34 (19), 2109367.
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Hwang, Y.; Ibrahim, M. S. B.; Deng, J.; Jackman, J. A.; Cho, N.-J. 3D Pollen Sponge: Colloid-Mediated Fabrication of a 3D Pollen Sponge for Oil Remediation Applications (Adv. Funct. Mater. 24/2021). Adv. Funct. Mater. 2021, 31 (24), 2170173. https://doi.org/10.1002/adfm.202170173.
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Hwang, Y.; Kim, M. K.; Zhao, Z.; Kim, B.; Chang, T.; Fan, T. F.; Ibrahim, M. S.; Suresh, S.; Lee, C. H.; Cho, N.-J. Plant-Based Substrate Materials for Flexible Green Electronics. Adv. Mater. Technol. 2022, 7 (12), 2200446. https://doi.org/10.1002/admt.202200446.
Will there be any allergenic concerns when using pollen as biomaterials?
Significant research works on pollen-based drug carrier systems in the material science and pharmaceutical field have demonstrated that well-treated pollen grains (or defatted pollen grains) were bio-safe without causing any allergy (1-7).
To avoid potential biosafety issues due to allergy, we similarly utilize only defatted pollen for our process to transform pollen grains into soft microgel particles. Defatted pollen is treated with 10 w/v% potassium hydroxide to remove its internal cytoplasmic content, which contains allergens (8). As a result, all pollen-based materials derived from this process are free of allergens and completely safe for use in biomedical applications.

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Fan, Hwang, Potroz, Lau, Tan, Ibrahim, Miyako & Cho. Degradation of the sporopollenin exine capsules (SECs) in human plasma. Applied Materials Today 19, 100594 (2020).
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Mundargi, Potroz, Park, Seo, Tan, Lee & Cho. Eco-friendly streamlined process for sporopollenin exine capsule extraction. Scientific reports 6, 19960 (2016).
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Mundargi, Potroz, Park, Park, Shirahama, Lee, Seo & Cho. Lycopodium spores: a naturally manufactured, superrobust biomaterial for drug delivery. Advanced Functional Materials 26, 487-497 (2016).
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Mundargi, Potroz, Park, Shirahama, Lee, Seo & Cho. Natural sunflower pollen as a drug delivery vehicle. Small 12, 1167-1173 (2016).
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Paunov, Mackenzie & Stoyanov. Sporopollenin micro-reactors for in-situ preparation, encapsulation and targeted delivery of active components. Journal of Materials Chemistry 17, 609-612 (2007).
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Uddin & Gill. Ragweed pollen as an oral vaccine delivery system: mechanistic insights. Journal of Controlled Release 268, 416-426 (2017).
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Diego-Taboada, Maillet, Banoub, Lorch, Rigby, Boa, Atkin & Mackenzie. Protein free microcapsules obtained from plant spores as a model for drug delivery: ibuprofen encapsulation, release and taste masking. Journal of Materials Chemistry B 1, 707-713 (2013)
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Fan, T.-F.; Park, S.; Shi, Q.; Zhang, X.; Liu, Q.; Song, Y.; Chin, H.; Ibrahim, M. S. B.; Mokrzecka, N.; Yang, Y. Transformation of Hard Pollen into Soft Matter. Nat. Commun. 2020, 11 (1), 1449.
Image : Mundargi, R. C., Potroz, M. G., Park, J. H., Seo, J., Tan, E. L., Lee, J. H., & Cho, N. J. (2016). Eco-friendly streamlined process for sporopollenin exine capsule extraction. Scientific reports, 6(1), 19960.