Morphogenesis and nanomanufacturing of synthetic brochosomes and their applications

Choi, Jinsol

Morphogenesis and nanomanufacturing of synthetic brochosomes and their applications

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Author:: Choi, Jinsol
Graduate Program:: Mechanical Engineering
Degree:: Doctor of Philosophy
Document Type:: Dissertation
Date of Defense:: September 10, 2024
Committee Members:: Robert Kunz, Professor in Charge/Director of Graduate Studies
Pak Kin Wong, Outside Field Member
Tak Sing Wong, Chair & Dissertation Advisor
Xiang Yang, Major Field Member
Lauren Zarzar, Outside Unit Member
Keywords:: Leafhopper
Brochosomes
Synthetic Brochosomes
Microfluidics
Nanomanufacturing
Bioinspired Materials
Abstract:: Brochosomes, considered some of the most intricate structures in nature, are three-dimensional microscopic granules typically exhibiting buckyball-like shape with nanoscale cavities. Leafhoppers produce brochosomes in Malpighian tubules, which are convoluted microscopic tubular structures responsible for brochosome synthesis using proteins and lipids. These Malpighian tubules generate a large population of brochosomes that are either highly monodispersed or polydispersed, maintaining consistent surface features within individual leafhopper species. Owing to the sophisticated three-dimensional geometry and the microscopic and nanoscopic dimensions of brochosomes, creating large quantities of their synthetic counterparts has remained an outstanding technological challenge even with state-of-the-art micro- and nanofabrication technologies. Here, we demonstrate a droplet microfluidic system mimicking the capability of Malpighian tubules to generate synthetic brochosomes using amphiphilic block copolymers and surfactants through evaporation-induced self-assembly and interfacial tension-driven morphogenesis processes. This “synthetic leafhopper” system is capable of producing monodispersed or polydispersed synthetic brochosomes of various geometries at a production rate of over 10⁵ particles per second, which is four orders of magnitude higher than the state-of-art 3D printing technology and with molecular resolution. By tuning the ratio of the hydrophobic and hydrophilic domains of the block copolymers and their molecular weight, we produced synthetic brochosomes that closely emulate the surface morphologies of natural brochosomes generated by five different leafhopper species, with particle diameters ranging from 390 nm to 2 µm and pore diameters from 30 nm to 500 nm. The molecular parameters of the block copolymers required to generate synthetic brochosomes with geometry akin to their natural counterparts are similar to the molecular composition of their constituent proteins and lipids, implying that our synthetic leafhopper could offer key insights into the biological production of brochosomes. Our synthetic leafhopper system enables high-throughput manufacturing of micro- and nanoscale synthetic brochosomes at molecular resolution making them suitable for a wide range of applications where uniform particle size and precise control of morphology and geometry are crucial. By using the highly monodispersed synthetic brochosomes, we demonstrated their potential optical applications such as obscurants for directional visibility, broadband antireflective coatings, and structural whitening agents.

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