title: Synthesis of bioactive microcapsules using a microfluidic device.
abstract: Bioactive microcapsules containing Bacillus thuringiensis (BT) spores were generated by a combination of a hydro gel, microfluidic device and chemical polymerization method. As a proof-of-principle, we used BT spores displaying enhanced green fluorescent protein (EGFP) on the spore surface to spatially direct the EGFP-presenting spores within microcapsules. BT spore-encapsulated microdroplets of uniform size and shape are prepared through a flow-focusing method in a microfluidic device and converted into microcapsules through hydrogel polymerization. The size of microdroplets can be controlled by changing both the dispersion and continuous flow rate. Poly(N-isoproplyacrylamide) (PNIPAM), known as a hydrogel material, was employed as a biocompatible material for the encapsulation of BT spores and long-term storage and outstanding stability. Due to these unique properties of PNIPAM, the nutrients from Luria-Bertani complex medium diffused into the microcapsules and the microencapsulated spores germinated into vegetative cells under adequate environmental conditions. These results suggest that there is no limitation of transferring low-molecular-weight-substrates through the PNIPAM structures, and the viability of microencapsulated spores was confirmed by the culture of vegetative cells after the germinations. This microfluidic-based microencapsulation methodology provides a unique way of synthesizing bioactive microcapsules in a one-step process. This microfluidic-based strategy would be potentially suitable to produce microcapsules of various microbial spores for on-site biosensor analysis.
authors.affiliation: Center for Nanobio Integration & Convergence Engineering (NICE), National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon 305-806, Korea. kbiset@nnfc.re.kr
authors.forename: Byeong Il
authors.initials: BI
authors.lastname: Kim
authors.forename: Soon Woo
authors.initials: SW
authors.lastname: Jeong
authors.forename: Kyoung G
authors.initials: KG
authors.lastname: Lee
authors.forename: Tae Jung
authors.initials: TJ
authors.lastname: Park
authors.forename: Jung Youn
authors.initials: JY
authors.lastname: Park
authors.forename: Jae Jun
authors.initials: JJ
authors.lastname: Song
authors.forename: Seok Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Chang-Soo
authors.initials: CS
authors.lastname: Lee
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D001413:Bacillus thuringiensis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015374:Biosensing Techniques / Q000295:instrumentation; D001709:Biotechnology / Q000295:instrumentation; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D020100:Hydrogels / Q000737:chemistry; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D008863:Microspheres; D010316:Particle Size; D013171:Spores, Bacterial / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D020100:Hydrogels; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C052970:poly-N-isopropylacrylamide
keywords: NIPAM; hydrogel; microcapsulation; microfluidic device; spore