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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) Droplet size variation graph with both different flow rates of CP flow rate (1–5 μL/min) and DP (1–5 μL/min). Optical microscopic images of microdroplet generation at the fixed CP (2 μL/min) with four different flow rates of DP. (B) QDP1 = 1 μL/min, (C) QDP2 = 2 μL/min, (D) QDP3 = 3 μL/min, (E) QDP4 = 4 μL/min.
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f2-sensors-12-10136: (A) Droplet size variation graph with both different flow rates of CP flow rate (1–5 μL/min) and DP (1–5 μL/min). Optical microscopic images of microdroplet generation at the fixed CP (2 μL/min) with four different flow rates of DP. (B) QDP1 = 1 μL/min, (C) QDP2 = 2 μL/min, (D) QDP3 = 3 μL/min, (E) QDP4 = 4 μL/min.

Mentions: The production of different sizes of bioactive microcapsules is important to control the amount of loading of biomolecules, cells or biomaterials for further applications. For this reason, the microdroplet-based microfluidic device was fabricated for controlling the size of microcapsules. The size of microdroplets was simply controlled by changing of both CP and DP flow rate in the microfluidic device, and the results are demonstrated in both Figure 2 and Figure S1–S4. Figure 2(A) shows the relationships between the droplet size and CP and DP flow rates in the microfluidic device. Under the same CP flow rate, the high-flow rate of DP generates the relatively large size of microdroplets compared to the low-flow rate of DP. Moreover, as increasing the CP flow rate under the same DP flow rate, the size of produced microdroplets is decreased. These results indicate that high-flow rate of CP strengthens the shearing force and accelerate the detachment of the droplets from the DP flow at the orifice in the microfluidic device. Because of this mechanism, a broad size range of microdroplets from 186 μm to 61 μm was easily obtained using a microfluidic device by controlling both CP and DP.


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) Droplet size variation graph with both different flow rates of CP flow rate (1–5 μL/min) and DP (1–5 μL/min). Optical microscopic images of microdroplet generation at the fixed CP (2 μL/min) with four different flow rates of DP. (B) QDP1 = 1 μL/min, (C) QDP2 = 2 μL/min, (D) QDP3 = 3 μL/min, (E) QDP4 = 4 μL/min.
© Copyright Policy
Related In: Results  -  Collection

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

f2-sensors-12-10136: (A) Droplet size variation graph with both different flow rates of CP flow rate (1–5 μL/min) and DP (1–5 μL/min). Optical microscopic images of microdroplet generation at the fixed CP (2 μL/min) with four different flow rates of DP. (B) QDP1 = 1 μL/min, (C) QDP2 = 2 μL/min, (D) QDP3 = 3 μL/min, (E) QDP4 = 4 μL/min.
Mentions: The production of different sizes of bioactive microcapsules is important to control the amount of loading of biomolecules, cells or biomaterials for further applications. For this reason, the microdroplet-based microfluidic device was fabricated for controlling the size of microcapsules. The size of microdroplets was simply controlled by changing of both CP and DP flow rate in the microfluidic device, and the results are demonstrated in both Figure 2 and Figure S1–S4. Figure 2(A) shows the relationships between the droplet size and CP and DP flow rates in the microfluidic device. Under the same CP flow rate, the high-flow rate of DP generates the relatively large size of microdroplets compared to the low-flow rate of DP. Moreover, as increasing the CP flow rate under the same DP flow rate, the size of produced microdroplets is decreased. These results indicate that high-flow rate of CP strengthens the shearing force and accelerate the detachment of the droplets from the DP flow at the orifice in the microfluidic device. Because of this mechanism, a broad size range of microdroplets from 186 μm to 61 μm was easily obtained using a microfluidic device by controlling both CP and DP.

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