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Study on bioresorbable, flexible porous silicon needle patch
Yale Jeon(전예일),Hyungjun Kim(김형준),Chi Hwan Lee(이지환),Dong Rip Kim(김동립) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
Miniaturized needles enable minimally invasive topical delivery of drug molecules to biological targets. Recently, miniaturized porous-silicon (p-Si) needles are emerging as an attractive candidate for intra-tissue drug injection due to their biocompatibility and controlled biodegradability. Here, we discuss the fabrication method and characteristics of bioresorbable miniaturized p-Si needles. To create a bioresorbable drug delivery platform, vertically aligned p-Si needles arrays are integrated into a water-soluble and flexible substrate by using a transfer printing technique. The p-Si needles remain inserted into the tissue and gradually dissolve, allowing for the sustained release of the drug molecules.
Jeon, Min Soo,Jeon, Yale,Hwang, Jeong Hoon,Heu, Chang Sung,Jin, Sangrak,Shin, Jongoh,Song, Yoseb,Chang Kim, Sun,Cho, Byung-Kwan,Lee, Jung-Kul,Kim, Dong Rip Elsevier 2018 Carbon Vol.130 No.-
<P><B>Abstract</B></P> <P>Here, we demonstrate the fabrication of 3D porous carbon scaffolds with tunable pore sizes that are comparable to the sizes of bacterial cells for their effective confinement. We utilized the sphere template method to fabricate the 3D porous carbon scaffolds with excellent pore arrangements and enlarged interconnected areas among the pores. The proposed 3D porous carbon scaffolds trapped about 40 times higher densities of <I>Escherichia coli</I> DH5α than conventional 3D porous reticulated vitreous carbon (RVC) scaffolds. Moreover, the proposed porous scaffolds effectively restrain the detachment of the attached cells from the scaffolds because of their geometries, thereby maintaining about 75% of the initial cell densities under repeated washing, whereas almost all the cells were washed away from the conventional 3D porous RVC scaffolds. This effective confinement of bacterial cells will assist in significantly improving the performance of cell-based biological applications.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Patel, Sanjay K. S.,Jeon, Min Soo,Gupta, Rahul K.,Jeon, Yale,Kalia, Vipin Chandra,Kim, Sun Chang,Cho, Byung Kwan,Kim, Dong Rip,Lee, Jung-Kul American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.21
<P>A viable approach for methanol production under ambient physiological conditions is to use greenhouse gases, methane (CH<SUB>4</SUB>) and carbon dioxide (CO<SUB>2</SUB>), as feed for immobilized methanotrophs. In the present study, unique macroporous carbon particles with pore sizes in the range of ∼1-6 μm were synthesized and used as support for the immobilization of <I>Methylocella tundrae</I>. Immobilization was accomplished covalently on hierarchical macroporous carbon particles. Maximal cell loading of covalently immobilized <I>M. tundrae</I> was 205 mg<SUB>DCM</SUB> g<SUP>-1</SUP> of particles. Among these particles, the cells immobilized on 3.6 μm pore size particles showed the highest reusability with the least leaching and were chosen for further study. After immobilization, <I>M. tundrae</I> showed up to 2.4-fold higher methanol production stability at various pH and temperature values because of higher stability and metabolic activity than free cells. After eight cycles of reuse, the immobilized cells retained 18.1-fold higher relative production stability compared to free cells. Free and immobilized cells exhibited cumulative methanol production of 5.2 and 9.5 μmol mg<SUB>DCM</SUB><SUP>-1</SUP> under repeated batch conditions using simulated biogas [CH<SUB>4</SUB> and CO<SUB>2</SUB>, 4:1 (v/v)] as feed, respectively. The appropriate pore size of macroporous particles favors the efficient <I>M. tundrae</I> immobilization to retain better biocatalytic properties. This is the first report concerning the covalent immobilization of methanotrophs on the newly synthesized macroporous carbon particles and its subsequent application in repeated methanol production using simulated biogas as a feed.</P> [FIG OMISSION]</BR>