Fabrication of multicompartmental particles with geometrical and chemical anisotropy by using the simple micromolding technique

심규락,정성근,이창수 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Recently Particles with geometrical and chemical anisotropy have a great influence on many fields. Herein, we introduce the simple and fast method called the micromolding technique of fabricating multicompartmental particles with geometrical and chemical anisotropy. By using this method, we can fabricate particles with various shape and properties. Especially, in this study, we synthesize particles with the cylindrical shape and co-existing the hydrophobicity and hydrophilicity. Finally, we fabricate multicompartmental and cylindrical particles with a size from several to tens of micrometers using this technique. In conclusion, we simply and rapidly fabricate particles with the cylindrical shape and co-existing the hydrophobicity and hydrophilicity by using the micromolding technique. This synthesized particles will be utilized to many applications of new materials and self-assembly.

미세성형 기술과 패치의 선택적 제거방법을 이용한 이방성의 육각별 입자 제조

심규락,염수진,정성근,강경구,이창수,Shim, Gyurak,Yeom, Su-Jin,Jeong, Seong-Geun,Kang, Kyoung-Ku,Lee, Chang-Soo 한국청정기술학회 2018 청정기술 Vol.24 No.2

본 연구는 입자 내에서 패치의 위치를 정교하게 제어할 수 있는 새로운 친환경 공정기술에 관한 것이다. 물리화학적으로 안정한 소재를 활용한 미세성형 기술과 패치의 위치를 제어할 수 있는 선택적 제거방법을 결합하여 수행하였다. 미세성형 기술에는 이방성 구조의 패치입자의 형상을 안정적으로 구현하기 위하여, perfluoropolyether (PFPE) 마이크로몰드를 사용하였다. 이를 통하여, 소수성의 패치소재가 poly(dimethylsiloxane) (PDMS) 마이크로몰드 내로 확산되는 문제를 극복할 수 있었다. 그리고, 이는 패치의 우수한 형상 안정성과 소수성 패치소재를 이용한 패치입자 제조를 가능하게 하였다. 마지막으로 패치의 위치가 서로 다른 12종의 패치입자를 제조하여 향상된 공정 안정성을 확인하였다. 본 연구에서 제시한 미세성형 기술과 패치의 선택적 제거방법은 패치의 위치가 선택적으로 제어된 이방성의 입자를 적은 공정의 수를 거쳐 빠르게 제조할 수 있는 장점을 가진다. 또한 제조된 패치입자는 방향성이 유도된 자기조립 분야, 조절이 가능한 약물 전달 시스템 등의 다양한 연구에 널리 활용될 수 있으리라 기대한다. This study presents a novel and eco-friendly process that can precisely control the location of the patches on the patch particles. The method of manufacturing these anisotropic hexagram patch particles consists of sequential combinations of two separate methods such as a sequential micromolding technique for fabricating patch particles and a selective localization method for controlling the location of patches on the patch particles. The micromolding technique was carried out using physicochemically stable material as a micromold. In order to fabricate the highly stable patch anisotropic hexagram particles, the perfluoropolyether (PFPE) micromold was used to the process of the micromolding technique because they could prevent the problem of diffusion of hydrophobic monomers while conventional poly(dimethylsiloxane) (PDMS) micromold is limited to prevent the problem of diffusion of hydrophobic monomers. Based on combination methods of the micromolding technique and the selective localization method, the reproducibility and stability have been improved to fabricate 12 different types of anisotropic hexagram patch particles. This fabrication method shows the unique advantages in eco-friend condition, easy and fast fabrication due to less number of process, the feasibility of a mass production. We believe that these anisotropic hexagram patch particles can be widely utilized to the field of the directional self-assembly.

1LP-23 Preparation of di-compartmental particles with anisotropic geometry and chemical property

심규락,염수진,정성근,김종민,이창수 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Janus particles can contain and transfer various materials with different properties, can be relatively easy to obtain the desired structures. Therefore, in this study, we synthesize di-compartmental particles with having both hydrophilic and hydrophobic properties and cylindrical morphology. Micromolding technique is a method to obtain particles through sequential loading and photopolymerization of materials with different properties to the micromold. Herein, we control the compartment of the hydrophilic part and hydrophobic part by adjusting the concentration of the solvent in the solution. Finally, we synthesize di-compartmental and cylindrical particles with different sizes by using the micromolding technique and adjusting the concentration of the solvent. We anticipate that this synthesized particles are utilized to incorporation of different materials and selective release at the target location, formation of particularly desired structure through self-assembly.

미세 성형 방법을 이용한 형광 표지된 이중 분획 입자의 제조

심규락,정성근,홍우경,강경구,이창수 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.6

This study presents fabrication of bi-compartmental particles labeled by multiple fluorescence. To compartmentalize fluorescent expression at the particle, two fluorescent dyes with less overlap of the excitation and emission spectra are selected. To ensure the fluorescence stability, the fluorescent dyes contain acrylate functional groups in the molecules so that they can be cross-linked together with monomers constituting the particle. Strong fluorescent expression and compartmentalization were observed at the particle fabricated using the selected fluorescent dyes through confocal microscopy. Furthermore, long-term fluorescence stability was verified by measuring fluorescent expression and intensity for 4 weeks. We anticipate that the bi-compartmental particles labeled by multiple fluorescence can be widely used for multi-target drug delivery system, analysis of 3 dimensional Brownian motion, and investigation of 3 dimensional complex self-assembled morphologies. 본 연구는 다중 형광이 표지된 이중 분획 입자의 제조에 관한 것이다. 입자 내에서 형광 발현을 분획화하기 위하여, 형광의 여기 및 방출 스펙트럼의 중첩이 적은 두가지의 형광 염료를 선정한다. 또한, 형광 안정성을 확보하기 위하여선정된 형광 염료는 입자를 구성하는 소재와 함께 가교될 수 있도록 분자 내에 아크릴레이트(acrylate) 작용기를 포함한다. 공초점 현미경 촬영을 통하여 선정된 형광 물질을 이용하여 제조된 입자에서 강한 형광 발현 및 형광의 분획화를 확인하였다. 더 나아가 4주 동안 형광 발현 및 세기를 측정하여 장기간의 형광 안정성을 검증하였다. 본 연구에서제조된 다중 형광 표지된 이중 분획 입자는 다중 표적형 약물 전달 체계, 3차원 브라운 운동의 해석 연구, 3차원의 복잡한 자기 조립체 형상의 규명 연구 등에 널리 활용될 수 있으리라 기대한다.

Control of compartment in Janus microcylinder particles using micromolding technique

심규락,정성근,이창수 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Janus microparticles have different chemical properties, such as hydrophobicity and hydrophilicity, and have unique are widely utilized in self-assembly, molecular simulation, and Pickering emulsion. In this study, we fabricate Janus micropaticles with different size and cylindrical morphology. We fabricate Janus microcylinders by using simple micromolding technique. Micromolding technique proceeds in sequential loading of two different photo-curable solutions and photo-polymerization. And, we synthesize Janus microcylinders with different sizes by controlling mold geometry. Finally, we easily fabricated Janus microcylinders with different sizes by simple micromolding technique, and we expect that they are useful in many fields.

Brownian motion of anisotropic particles in microgravity

심규락,정성근,( William V. Meyer ),( Ronald J. Sicker ),( Dan Brown ),이창수 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In the universe, Brownian motion is fascinating phenomena that give great impact in the field of science and engineering. On earth, it is experimentally difficult to observe original Brownian motion of anisotropic particle due to buoyancy-driven force and sedimentation. Their original 3-dimensional (3D) Brownian motion is replaced by quasi 2-dimensional (2D) motion at long time scale because the colloidal particles usually settle down in a liquid due to gravity. Here we report the observation of 3D rotational Brownian motion of anisotropic colloidal particle in International Space Station (ISS) with the Light microscopy module (LMM). We find that the hydrophobic surface enhance their 3D rotational Brownian motion. Our observation is the measurement of 3D rotational Brownian motion of an anisotropic colloidal particle in microgravity where one can connect the combined effects of shape with the amount of a hydrophobic surface present.

Improvement in the Reproducibility of a Paper-based Analytical Device (PAD) Using Stable Covalent Binding between Proteins and Cellulose Paper

홍우경,정성근,심규락,김대영,백승필,이창수 한국생물공학회 2018 Biotechnology and Bioprocess Engineering Vol.23 No.6

Paper-based analytical devices (PADs) have been widely used in many fields because they are affordable and portable. For reproducible quantitative analysis, it is crucial to strongly immobilize proteins on PADs. Conventional techniques for immobilizing proteins on PADs are based on physical adsorption, but proteins can be easily removed by weak physical forces. Therefore, it is difficult to ensure the reproducibility of the analytical results of PADs using physical adsorption. To overcome this limitation, in this study, we showed a method of covalent binding of proteins to cellulose paper. This method consists of three steps, which include periodate oxidation of paper, the formation of a Schiff base, and reductive amination. We identified aldehyde and imine groups formed on paper using FT-IR analysis. This covalent bonding approach enhanced the binding force and binding capacity of proteins. We confirmed the activity of an immobilized antibody through a sandwich immunoassay. We expect that this immobilization method will contribute to the commercialization of PADs with high reproducibility and sensitivity.

2LO-9 Multiplexed digital assay in a three-dimensional paper-based microfluidic analytical device

정성근,진시형,이병진,심규락,김동영,강소립,이창수 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Here, we demonstrate 3-dimensional (3D) paper-based microfluidic channels to control 3D flow for automatic multiplexed digital assay. The 3D channels were fabricated by double-sided printing and lamination process. We print and laminate asymmetrical and symmetrical wax patterns on the paper to form 3D channels, and to create 3D fluidic flow for multiplexed digital assay. The 3D channels contains lateral and vertical channel. The asymmetrical wax-patterns form lateral and vertical channels. The symmetrical wax-patterns form vertical channels when the melted wax make contact with each other. We injected red dye into inlet of channels to track 3D capillary flow in the 3D channel. We conformed that the 3D fluid flow in a thickness of a paper. Based on this concept, we created 3D devices for automatic digital assay to detect glucose and albumin. Therefore, we expect that this method could be an instrument-free and multiplexed assay format for use in developing countries.

미세유체 장치에서 부분젤화법을 이용한 단분산성 펙틴 하이드로젤 미세섬유의 제조

진시형,김채연,이병진,심규락,김동영,이창수 한국청정기술학회 2017 청정기술 Vol.24 No.3

This study introduces a method to easily fabricate highly monodisperse pectin hydrogel microfibers in a microfluidic device by using partial gelation. The hydrodynamic parameters between the pectin aqueous solution and the calcium ions containing oil solution are precisely controlled to form a stable elongation flow of the pectin aqueous solution, and partial gelation of the pectin aqueous solution is performed by the chelating of the calcium ions at the interface between the two phases. The partially gelled pectin aqueous solution is phase-separated from the oil solution in an aqueous calcium chloride solution outside the microfluidic device and is completely gelled to produce monodisperse pectin hydrogel microfibers. The thickness of the pectin hydrogel microfiber is controlled in a reproducible manner by controlling the volumetric flow rate of the initially injected pectin aqueous solution. The pectin hydrogel microfibers were 200 to 500 micrometers in diameter and had a coefficient of variation below 5% under all thickness conditions, indicating that the pectin hydrogel microfibers produced by partial gelation are highly monodisperse. In addition, biomaterials can be immobilized to the pectin hydrogel microfibers produced by a single process, demonstrating the possibility that our pectin hydrogel microfiber can be used as carriers for biomaterials or tissue engineering. 본 연구는 미세유체 장치에서 매우 균일한 펙틴 하이드로젤 미세섬유를 부분젤화법을 통해 손쉽게 제조하는 방법을 소개한다. 펙틴 수용액과 이와 섞이지 않는 칼슘이 분산된 오일용액 사이의 수력학적 변수들을 조절하여 펙틴 수용액의 흐름을 안정적으로 늘어진 유동을 형성하고 두 상의 계면에서 칼슘 이온의 킬레이트화 반응으로 펙틴 수용액을 부분젤화 시킨다. 부분젤화된 펙틴 수용액은 미세유체 장치 외부의 염화칼슘 수용액에서 오일 용액과 상분리 되고 완전히 젤화되어 미세섬유로제조된다. 펙틴 하이드로젤 미세섬유의 굵기는 초기 주입되는 펙틴 수용액의 부피유속을 조절함으로써 재현성 있게 제어된다. 제조된 펙틴 하이드로젤 미세섬유의 직경은 200에서 500 마이크로미터 범위이며 모든 두께 조건에서 5% 이하의 변동계수를 가짐으로써 매우 균일함을 증명하였다. 또한 펙틴 하이드로젤 미세섬유에 생체물질을 단일공정으로 고정화 함으로써생체물질 담지체나 조직공학의 지지체로써 사용될 수 있는 가능성을 보여준다.

미세유체 장치에서 부분젤화법을 이용한 단분산성 펙틴 하이드로젤 미세섬유의 제조

진시형(Si Hyung Jin),김채연(Chaeyeon Kim),이병진(Byungjin Lee),심규락(Kyu-Rak Shim),김동영(Dong Young Kim),이창수(Chang-Soo Lee) 한국청정기술학회 2017 청정기술 Vol.23 No.3

본 연구는 미세유체 장치에서 매우 균일한 펙틴 하이드로젤 미세섬유를 부분젤화법을 통해 손쉽게 제조하는 방법을 소개한다. 펙틴 수용액과 이와 섞이지 않는 칼슘이 분산된 오일용액 사이의 수력학적 변수들을 조절하여 펙틴 수용액의 흐름을 안정적으로 늘어진 유동을 형성하고 두 상의 계면에서 칼슘 이온의 킬레이트화 반응으로 펙틴 수용액을 부분젤화 시킨다. 부분젤화된 펙틴 수용액은 미세유체 장치 외부의 염화칼슘 수용액에서 오일 용액과 상분리 되고 완전히 젤화되어 미세섬유로 제조된다. 펙틴 하이드로젤 미세섬유의 굵기는 초기 주입되는 펙틴 수용액의 부피유속을 조절함으로써 재현성 있게 제어된다. 제조된 펙틴 하이드로젤 미세섬유의 직경은 200에서 500 마이크로미터 범위이며 모든 두께 조건에서 5% 이하의 변동계수를 가짐으로써 매우 균일함을 증명하였다. 또한 펙틴 하이드로젤 미세섬유에 생체물질을 단일공정으로 고정화 함으로써 생체물질 담지체나 조직공학의 지지체로써 사용될 수 있는 가능성을 보여준다. This study introduces a method to easily fabricate highly monodisperse pectin hydrogel microfibers in a microfluidic device by using partial gelation. The hydrodynamic parameters between the pectin aqueous solution and the calcium ions containing oil solution are precisely controlled to form a stable elongation flow of the pectin aqueous solution, and partial gelation of the pectin aqueous solution is performed by the chelating of the calcium ions at the interface between the two phases. The partially gelled pectin aqueous solution is phase-separated from the oil solution in an aqueous calcium chloride solution outside the microfluidic device and is completely gelled to produce monodisperse pectin hydrogel microfibers. The thickness of the pectin hydrogel microfiber is controlled in a reproducible manner by controlling the volumetric flow rate of the initially injected pectin aqueous solution. The pectin hydrogel microfibers were 200 to 500 micrometers in diameter and had a coefficient of variation below 5% under all thickness conditions, indicating that the pectin hydrogel microfibers produced by partial gelation are highly monodisperse. In addition, biomaterials can be immobilized to the pectin hydrogel microfibers produced by a single process, demonstrating the possibility that our pectin hydrogel microfiber can be used as carriers for biomaterials or tissue engineering.