Preserving the inflated structure of lyophilized sporopollenin exine capsules with polyethylene glycol osmolyte

Michael K. Corliss,Chuan Kiat Bok,Jurriaan Gillissen,Michael G. Potroz,정하람,Ee-Lin Tan,Raghavendra C. Mundargi,조남준 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.61 No.-

Extracted from natural pollen grains, sporopollenin exine capsules (SECs) are robust, chemically inert biopolymer shells that posess highly uniform size and shape characteristics and that can be utilized as hollow microcapsules for drug delivery applications. However, it is challenging to extract fully functional SECs from many pollen species because pollen grains often collapse, causing the loss of architectural features, loading volume, and bulk uniformity. Herein, we demonstrate that polyethylene glycol (PEG) osmolyte solutions can help preserve the native architectural features of extracted SECs, yielding inflated microcapsules of high uniformity that persist even after subsequent lyophilization. Optimal conditions were first identified to extract SECs from cattail (Typhae angustfolia) pollen via phosphoric acid processing after which successful protein removal was confirmed by elemental (CHN), mass spectrometry (MALDI-TOF), and confocal laser canning microscopy (CLSM) analyses. The shape of SECs was then assessed by scanning electron microscopy (SEM) and dynamic image particle analysis (DIPA). While acid-processed SECs experienced high degrees of structural collapse, incubation in 2.5% or higher PEG solutions significantly improved preservation of spherical SEC shape by inducing inflation within the microcapsules. A theoretical model of PEG-induced osmotic pressure effects was used to interpret the experimental data, and the results show excellent agreement with the known mechanical properties of pollen exine walls. Taken together, these findings demonstrate that PEG osmolyte is a useful additive for preserving particle shape in lyophilized SEC formulations, opening the door to broadly applicable strategies for stabilizing the structure of hollow microcapsules.

Chemical processing strategies to obtain sporopollenin exine capsules from multi-compartmental pine pollen

Arun Kumar Prabhakar,Hui Ying Lai,Michael G. Potroz,Michael K. Corliss,박재현,Raghavendra C. Mundargi,조대호,방사익,조남준 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-

Pine pollen is widely used in traditional Chinese medicine and has been consumed as a food product for thousands of years. Owing to wind pollination, its pollen grains are composed of a sporoplasmic central cavity along with two empty air sac compartments. While this architectural configuration is evolutionarily optimized for wind dispersal, such features also lend excellent potential for encapsulating materials, especially in the context of preparing sporopollenin exine capsules (SECs). Herein, we systematically evaluated one-pot acid processing methods in order to generate pine pollen SECs that support compound loading. Morphological properties of the SECs were analysed by scanning electron microscopy (SEM) and dynamic imaging particle analysis (DIPA), and protein removal was evaluated by CHN elemental analysis and confocal laser scanning microscopy (CLSM). It was identified that 5-h acidolysis with 85% w/v phosphoric acid at 70 C yielded an optimal balance of high protein removal and preservation of microcapsule architecture, while other processing methods were also feasible with an additional enzymatic step. Importantly, the loading efficiency of the pine pollen SECs was three-times greater than that of natural pine pollen, highlighting their potential for microencapsulation. Taken together, our findings outline a successful strategy to prepare intact pine pollen SECs and demonstrate for the first time that SECs can be prepared from multi-compartmental pollen capsules, opening the door to streamlined processing approaches to utilize pine pollen microcapsules in industrial applications.

Chemical processing strategies to obtain sporopollenin exine capsules from multi-compartmental pine pollen

Prabhakar, A.K.,Lai, H.Y.,Potroz, M.G.,Corliss, M.K.,Park, J.H.,Mundargi, R.C.,Cho, D.,Bang, S.I.,Cho, N.J. Korean Society of Industrial and Engineering Chemi 2017 Journal of industrial and engineering chemistry Vol.53 No.-

Pine pollen is widely used in traditional Chinese medicine and has been consumed as a food product for thousands of years. Owing to wind pollination, its pollen grains are composed of a sporoplasmic central cavity along with two empty air sac compartments. While this architectural configuration is evolutionarily optimized for wind dispersal, such features also lend excellent potential for encapsulating materials, especially in the context of preparing sporopollenin exine capsules (SECs). Herein, we systematically evaluated one-pot acid processing methods in order to generate pine pollen SECs that support compound loading. Morphological properties of the SECs were analysed by scanning electron microscopy (SEM) and dynamic imaging particle analysis (DIPA), and protein removal was evaluated by CHN elemental analysis and confocal laser scanning microscopy (CLSM). It was identified that 5-h acidolysis with 85% w/v phosphoric acid at 70<SUP>o</SUP>C yielded an optimal balance of high protein removal and preservation of microcapsule architecture, while other processing methods were also feasible with an additional enzymatic step. Importantly, the loading efficiency of the pine pollen SECs was three-times greater than that of natural pine pollen, highlighting their potential for microencapsulation. Taken together, our findings outline a successful strategy to prepare intact pine pollen SECs and demonstrate for the first time that SECs can be prepared from multi-compartmental pollen capsules, opening the door to streamlined processing approaches to utilize pine pollen microcapsules in industrial applications.

Preserving the inflated structure of lyophilized sporopollenin exine capsules with polyethylene glycol osmolyte

Corliss, Michael K.,Bok, Chuan Kiat,Gillissen, Jurriaan,Potroz, Michael G.,Jung, Haram,Tan, Ee-Lin,Mundargi, Raghavendra C.,Cho, Nam-Joon THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.61 No.-

<P><B>Abstract</B></P> <P>Extracted from natural pollen grains, sporopollenin exine capsules (SECs) are robust, chemically inert biopolymer shells that posess highly uniform size and shape characteristics and that can be utilized as hollow microcapsules for drug delivery applications. However, it is challenging to extract fully functional SECs from many pollen species because pollen grains often collapse, causing the loss of architectural features, loading volume, and bulk uniformity. Herein, we demonstrate that polyethylene glycol (PEG) osmolyte solutions can help preserve the native architectural features of extracted SECs, yielding inflated microcapsules of high uniformity that persist even after subsequent lyophilization. Optimal conditions were first identified to extract SECs from cattail (<I>Typhae angustfolia</I>) pollen <I>via</I> phosphoric acid processing after which successful protein removal was confirmed by elemental (CHN), mass spectrometry (MALDI-TOF), and confocal laser canning microscopy (CLSM) analyses. The shape of SECs was then assessed by scanning electron microscopy (SEM) and dynamic image particle analysis (DIPA). While acid-processed SECs experienced high degrees of structural collapse, incubation in 2.5% or higher PEG solutions significantly improved preservation of spherical SEC shape by inducing inflation within the microcapsules. A theoretical model of PEG-induced osmotic pressure effects was used to interpret the experimental data, and the results show excellent agreement with the known mechanical properties of pollen exine walls. Taken together, these findings demonstrate that PEG osmolyte is a useful additive for preserving particle shape in lyophilized SEC formulations, opening the door to broadly applicable strategies for stabilizing the structure of hollow microcapsules.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Identified that polyethylene glycol (PEG) osmolyte can prevent SEC particle collapse. </LI> <LI> Chemical route to extract SECs from cattail pollen was achieved successfully. </LI> <LI> Model of PEG-induced osmotic pressure effects agrees with experimental data. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>