Preparation of carbon nanotube-wrapped porous microparticles using a microfluidic device

Carbon nanotubes (CNTs) have been generating much interest because they possess many advantages such as unique chemical, physical, and mechanical properties. CNTs can potentially be used in various fields such as bioengineering, biosensor, and nanotechnology. In particular, CNT polymer composites have good mechanical properties and high electrical conductivity, which are suitable for electrochemical biosensors. In our study, a microfluidic device was used to prepare CNT-attached poly(lactic-co-glycolic acid) (PLGA) microspheres with the narrow size distribution to control the release properties from microspheres. The microfluidic device was fabricated by casting conventional polydimethylsiloxane from a master mold. The PLGA solution and polyvinyl alcohol (PVA) solution were used as the dispersed phase and continuous phase. The PVA solution was coated on the microchannel to maintain their hydrophilicity for stable preparation of microspheres. The amine-functionalized CNTs were attached onto the prepared microspheres by non-ionic bonding. To evaluate their performance as biosensors, laccase was used as an attached enzyme on the microspheres. The morphology of the CNT-wrapped microspheres was inspected using scanning electron microscopy. The activity of the attached laccase on the microspheres was observed spectrophotometrically using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,4-dichlorophenol.