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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

(A) Microscopic images of polymerized PNIPAM microbeads. Scale bars are 50 μm; (B) FT-IR spectra of NIPAM and PNIPAM.
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f3-sensors-12-10136: (A) Microscopic images of polymerized PNIPAM microbeads. Scale bars are 50 μm; (B) FT-IR spectra of NIPAM and PNIPAM.

Mentions: As shown in Figure S1, the average produced droplet size was around 62 μm. After the produced microdroplets were polymerized, the monomers inside the droplets were polymerized and microcapsules were fabricated. During the polymerization process, the microcapsules maintained their uniform spherical shapes even after the polymerization, as shown in Figure 3, and the average produced PNIPAM microcapsules were 60.29 ± 2.19 μm in diameter, which is similar to the average size of microdroplets. There are slight changes of the diameter, and no shape changes were observed, as shown in Figure 3. This result demonstrates the successful fabrication of monodisperse microcapsules.


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)

(A) Microscopic images of polymerized PNIPAM microbeads. Scale bars are 50 μm; (B) FT-IR spectra of NIPAM and PNIPAM.
© Copyright Policy
Related In: Results  -  Collection

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

f3-sensors-12-10136: (A) Microscopic images of polymerized PNIPAM microbeads. Scale bars are 50 μm; (B) FT-IR spectra of NIPAM and PNIPAM.
Mentions: As shown in Figure S1, the average produced droplet size was around 62 μm. After the produced microdroplets were polymerized, the monomers inside the droplets were polymerized and microcapsules were fabricated. During the polymerization process, the microcapsules maintained their uniform spherical shapes even after the polymerization, as shown in Figure 3, and the average produced PNIPAM microcapsules were 60.29 ± 2.19 μm in diameter, which is similar to the average size of microdroplets. There are slight changes of the diameter, and no shape changes were observed, as shown in Figure 3. This result demonstrates the successful fabrication of monodisperse microcapsules.

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