From Tough Pollen to Soft Matter

Often regarded as the diamond of the plant kingdom, the pollen – as a class of material – is at once tough and soft. However, our understanding of how this structural adaptation allows pollen to deliver its biological functionality while displaying the stunning longevity, which often extends to geological time scales remains limited. Thus, the overarching intellectual and scientific vision for this proposal is to develop materials science of pollen. Specifically, we aim to systematically map fundamental relations between processes, structures, and properties spanning full range of relevant multiple length scales and produce comprehensive descriptions of the structure-dynamics-function relations characterizing pollen. We will implement a tightly integrated, highly collaborative, and a narrowly focused research strategy by focusing on a small sub-set of natural and engineered pollen and launching a systematic investigation to arrive at a quantitative map consolidating key structure-dynamics-properties-function relations that characterize the pollen as a material. To systematically alter material composition and structure of the pollen, we will engineer a natural variant using environmentally benign chemical methods. We will investigate the stability and environmental adaptability of a selection of natural and engineered pollens. We hypothesize that the pollen morphology must adopt folding pathways that maintain routes of communication and exchange with the environment, while preserving the structural integrity of the pollen grain. We reason that the fundamental understanding of how the material organization enables the pollen to generate negative feedback loops that respond to environmental assaults will not only provide basic understanding of pollen as a dynamic, responsive material but also yield fundamental design principles for the synthesis of novel pollen-mimetic matter. This will eventually lead to pollen-based materials for applications in drug delivery, tissue engineering, 3D printing, biosensing and beyond.