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Synthesis of bioactive microcapsules using a microfluidic device.

Kim BI, Jeong SW, Lee KG, Park TJ, Park JY, Song JJ, Lee SJ, Lee CS - Sensors (Basel) (2012)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanobio Integration & Convergence Engineering (NICE), National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon 305-806, Korea. kbiset@nnfc.re.kr

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.

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Related in: MedlinePlus

Schematic illustration of the BT spore-encapsulation process and the germination of BT spores in the microcapsules.
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f1-sensors-12-10136: Schematic illustration of the BT spore-encapsulation process and the germination of BT spores in the microcapsules.

Mentions: The major dimensions of microfluidic device were 50 μm of orifice and 100 μm of height for all microchannels, and the detailed dimensions of the microfluidic device and its picture are shown in Figure S1. For the production of microdroplet-based hydrogel beads, the mixture of NIPAM (20%, w/w), MBA (5%, w/w), initiator, and mixture solution of EGFP-displayed BT spores (1.0 × 105 CFU/mL) were injected through the center inlet of PDMS-based microfluidic device as a DP. In order to generate microdroplets, a mixture of G-oil and Abil Em90 as a surfactant was employed as a CP through the other inlets. The overall fabrication processes and the dimension of microfluidic device are schematically illustrated in Figures 1 and S1. In this study, the G-oil and Abil Em90 were selected because it is inert, immiscible with PNIPAM monomer and prevents the potential merging of produced microdroplets. As DP passing through the orifice of the device, the DP flow is squeezed and sheared off by applied CP flow and the orifice to form monodisperse microdroplets.


Synthesis of bioactive microcapsules using a microfluidic device.

Kim BI, Jeong SW, Lee KG, Park TJ, Park JY, Song JJ, Lee SJ, Lee CS - Sensors (Basel) (2012)

Schematic illustration of the BT spore-encapsulation process and the germination of BT spores in the microcapsules.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472820&req=5

f1-sensors-12-10136: Schematic illustration of the BT spore-encapsulation process and the germination of BT spores in the microcapsules.
Mentions: The major dimensions of microfluidic device were 50 μm of orifice and 100 μm of height for all microchannels, and the detailed dimensions of the microfluidic device and its picture are shown in Figure S1. For the production of microdroplet-based hydrogel beads, the mixture of NIPAM (20%, w/w), MBA (5%, w/w), initiator, and mixture solution of EGFP-displayed BT spores (1.0 × 105 CFU/mL) were injected through the center inlet of PDMS-based microfluidic device as a DP. In order to generate microdroplets, a mixture of G-oil and Abil Em90 as a surfactant was employed as a CP through the other inlets. The overall fabrication processes and the dimension of microfluidic device are schematically illustrated in Figures 1 and S1. In this study, the G-oil and Abil Em90 were selected because it is inert, immiscible with PNIPAM monomer and prevents the potential merging of produced microdroplets. As DP passing through the orifice of the device, the DP flow is squeezed and sheared off by applied CP flow and the orifice to form monodisperse microdroplets.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanobio Integration & Convergence Engineering (NICE), National Nanofab Center, 291 Daehak-ro, Yuseong-gu, Daejeon 305-806, Korea. kbiset@nnfc.re.kr

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.

Show MeSH
Related in: MedlinePlus