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.

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>

Fabrication of Hollow Metal Microcapsules with Mesoporous Shell Structure: Application as Efficient Catalysts Recyclable by Simple Magnetic Separation

장다영,김계령,장형규,김건중 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.9

Monodispersed porous NiO and Co_3O_4 microcapsules with a hollow core were synthesized using SBA-16 silica sol and PS as a hard template. The porous hollow microcapsules were characterized by XRD, TEM and N_2adsorption/desorption analysis. After H_2 reduction of metal oxide microspheres, they were conducted as an active catalyst in the reduction of chiral butylronitrile and cyanobenzene. The mesoporous metals having a hollow structure showed a higher activity than a nonporous metal powder and an impregnated metal on the carbon support.

Fabrication of Hollow Metal Microcapsules with Mesoporous Shell Structure: Application as Efficient Catalysts Recyclable by Simple Magnetic Separation

Jang, Da-Young,Jang, Hyung-Gyu,Kim, Gye-Ryung,Kim, Geon-Joong Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.9

Monodispersed porous NiO and $Co_3O_4$ microcapsules with a hollow core were synthesized using SBA-16 silica sol and PS as a hard template. The porous hollow microcapsules were characterized by XRD, TEM and $N_2$ adsorption/desorption analysis. After $H_2$ reduction of metal oxide microspheres, they were conducted as an active catalyst in the reduction of chiral butylronitrile and cyanobenzene. The mesoporous metals having a hollow structure showed a higher activity than a nonporous metal powder and an impregnated metal on the carbon support.

중간세공을 갖는 껍질로 구성된 속이 빈 마이크로 탄소입자의 합성 및 이들의 전기화학적 특성

이예원 ( Yae Won Lee ),양희천 ( Hee Chun Yang ),김건중 ( Geon Joong Kim ) 한국공업화학회 2016 공업화학 Vol.27 No.4

본 연구에서는 구형의 폴리스티렌 구슬을 틀로 사용하여, 크기분포가 좁으면서 속은 비어있고 벽이 다공성인 구조의 탄소 마이크로 캡슐을 합성하였다. 폴리스티렌의 표면은 무기물인 실리카졸이 쉽게 입혀질 수 있도록 폴리비닐피롤리돈(PVP)을 코팅하여 변조하였다. PVP가 코팅된 PS 마이크로 입자표면에 SBA-16 졸을 부착시킨 다음, 실리카층에 존재하는 중간 크기의 세공 내에 탄소원을 채워 넣는 음각식 형뜨기법을 적용함으로써 속이 빈 구조의 탄소 마이크로캡슐을 제조하였다. 탄화과정을 거치고 틀로 사용한 다공성 실리카입자를 HF로 용해하면, 좁은 입자크기분포를 갖는 중간세공이 함유된 계란껍질형의 탄소입자를 얻을 수 있었다. 계란껍질형 탄소 마이크로캡슐 입자의 다공성과 전기화 학적 특성은 XRD, SEM, TEM, 질소분자 흡/탈착분석법 및 cyclic voltammetry법으로 평가하였다. 이들 탄소입자는 슈퍼캐패시터와 같은 전자재료로서 유효하게 사용될 만한 높은 전기전도도와 용량을 나타내었다. In this study, highly monodispersed porous carbon microcapsules with a hollow core were synthesized using polystyrene (PS) beads as a hard template. The surface of PS was first modified with polyvinylpyrollidone (PVP) for the easy attachment of inorganic silica sol. After coating the surface of PVP modified PS microspheres with SBA-16 sol, the carbon microcapsules with a hollow macroporous core were fabricated through reverse replication method by filling carbon sources in the mesopores of silica mold. The hollow carbons having a mesoporous shell structure and narrow particle size distribution could be obtained after the carbonization of carbon source and the dissolution of silica mold by HF solution. The mesoporous characteristics and electrochemical properties of hollow carbon microcapsules were characterized by XRD, SEM, TEM, N2 adsorption/desorption analysis and cyclic voltammetry. They showed the high electric conductivity and capability for use as efficient electro-materials such as a supercapacitor.

中空 坐劑의 약물방출(Ⅰ) : Witepsol H-15 기제로부터의 인도메타신의 방출속도 Release Rate of Indomethacin from Witepsol H-15 Suppository

이화정,구영순 梨花女子大學校 藥學硏究所 1991 藥學硏究論文集 Vol.- No.1

In order to study drug release from the suppository, three types of hollow suppositories and one conventional suppository were prepared using indomethacin (IDM) as a model drug and Witepsol H-15 as a base. The 4 types of suppository prepared are as follows : typeⅠ, conventional suppository containing 50mg of IDM powder, typeⅡ, hollow suppository containing 50mg of IDM powder in the cavity, typeⅢ, hollow suppository containing 25mg of IDM powder in the base and IDM microcapsules (25mg as IDM powder) in the cavity, and type Ⅳ, hollow suppository containing IDM microcapsules (25mg as IDM powder) in the base ans 0.5ml of 5%(w/v) IDM-PEG 300 solution in the cavity. The drug amount released(%) from typeⅡ and Ⅰ within 24hrs was 46.7% and 66.9%, respectively. Comparing with the drug amount released from four types of suppository within initial 2hrs and 24hrs, that of type Ⅳ was high as 32.7% and 76.6%, respectively. IDM-ethycellulose microcapsules passed through 270 mesh sieve and the IDM content was 20.95%.

Poly(vinyl alcohol) hollow microcapsules prepared by emulsification, salting out, and photo cross-linking method

Mi Sun Lee,김진철,Eun Young Mok,Won Cheol Shin,Jong Dai Kim 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.8

Coumarin residues were conjugated to poly(vinyl alcohol) (PVA) by reacting epoxypropoxy coumarin (EPC) with the polymer. According to the peak areas on the 1H NMR spectrum, EPC was calculated to be conjugated to every 283 repeating units (vinyl alcohols). A cyclic photo-dimerization and dedimerization of EPC of PVA-EPC conjugate were observed under a cyclic irradiation of 365 nm and 254 nm. The salting-out of the conjugate significantly took a place in the range of 0-2.0M NaCl, and the phenomenon was observed at a lower concentration than that of unmodified PVA was. Oil-in-water emulsion was prepared as a template for the preparation of hollow microcapsules using chloroform as an oil phase and PVA-EPC as an emulsifier. The emulsion was stable for 24 hr in terms of droplet size. The wall surrounding droplets was built-up by the salting-out of PVA-EPC, and it was cross-linked by the irradiation of 365 nm. After chloroform was evaporated and salt was removed by a dialysis, hollow microcapsules were successfully obtained.

중공 좌제의 약물방출(I) - Witepsol H-15 기제로부터의 인도메타신의 방출속도 -

이화정(Hwa Jeong Lee),구영순(Young Soon Ku) 대한약학회 1991 약학회지 Vol.35 No.3

In order to study drug release from the suppository, three types of hollow suppositories and one conventional suppository were prepared using indomethacin(IDM) as a model drug and Witepsol H-15 as a base. The 4 types of suppository prepared are as follows: type I, conventional suppository containing 50 mg of IDM powder, type II, hollow supository containing 50 mg of IDM powder in the cavity, type III, hollow suppository containing 25 mg of IDM powder in the base and IDM microcapsules (25 mg as IDM powder) in the cavity, and type IV, hollow suppository containing IDM microcapsules (25 mg as IDM powder) in the base and 0.5 ml of 5%(w/v) IDM-PEG 300 solution in the cavity. The drug amount released(%) from type II and I within 24 hrs was 46.7% and 66.9%, respectively. Comparing with the drug amount released from four types of suppository within initial 2 hrs and 24 hrs, that of type IV was high as 32.7% and 76.6%, respectively. IDM-ethylcellulose microcapsules passed through 270 mesh sieve and the IDM content was 20.95%.

Fabrication of spherical CNT skeins formed by self-entangled fibers from hollow type mesoporous silica microcapsules

박근우,유재빈,김건중 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-

Various type CNT balls were fabricated using porous hollow microcapsules, and they were characterizedby XRD, TEM and N2 adsorption/desorption analysis. The CNT Balls tangled together showed extremelyimproved thermal and electrical properties as compared to thefibrous CNTs. Notably increased strainvalues, such as more than 30% strains atfixed stress, with high toughness have resulted in for thoseentangled CNT skeins. Even though the CNT skeins entangled together withfibrous bundles have beenfabricated as a multi wall-type, they could be applied successfully as a DNA separator and highlyconducting electrochemical/rheological materials.

Fabrication of spherical CNT skeins formed by self-entangled fibers from hollow type mesoporous silica microcapsules

Woo Park, Geun,Yoo, Jae Bin,Kim, Geon-Joong Elsevier 2019 Journal of industrial and engineering chemistry Vol.76 No.-

<P><B>Abstract</B></P> <P>Various type CNT balls were fabricated using porous hollow microcapsules, and they were characterized by XRD, TEM and N<SUB>2</SUB> adsorption/desorption analysis. The CNT Balls tangled together showed extremely improved thermal and electrical properties as compared to the fibrous CNTs. Notably increased strain values, such as more than 30% strains at fixed stress, with high toughness have resulted in for those entangled CNT skeins. Even though the CNT skeins entangled together with fibrous bundles have been fabricated as a multi wall-type, they could be applied successfully as a DNA separator and highly conducting electrochemical/rheological materials.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>