A modified microfluidic chip for fabrication of paclitaxel-loaded poly(l-lactic acid) microspheres

Abstract

In this article, we present a simple PDMS surface modification method based on poly(vinyl alcohol)/glycerol (PVA/Gly) solution immersion, self-assembled absorption, and heat treatment. The results of contact angle and ATR-FTIR demonstrate the superhydrophilic surface in modified PDMS. It can allow for the stable production of monodisperse droplet in a highly reproducible manner. In addition, we demonstrate the fabrication of monodisperse paclitaxel (PTX) loaded poly(L-lactic acid) (PLLA) microspheres on this kind of modification chip with solvent evaporation. The PLLA microspheres can be adjusted to a range of different sizes depending on the system flow rate. Determination of microsphere size is carried out by optical microscopy and image analysis to reveal less than 4% variation in microsphere size. Compared with the results of published papers, the presented data demonstrate that PTX-loaded PLLA microspheres show good physical properties (spherical and discrete), high-drug loading, encapsulation efficiency, a small initial burst, and sustained-release behavior due to outstanding monodispersity. With the characteristic to prepare high-quality, monodisperse, biodegradable microspheres, the versatile and simple microfluidic method facilitates the development of more reliable and reproducible drug delivery systems, which have great potential to benefit pharmaceutical and biological applications.

Hydrophilic surface modification of PDMS for droplet microfluidics using a simple, quick, and robust method via PVA deposition

“…We evaluated the level of the surface hydrophilicity induced by two commercially available PVA solutions commonly used in PDMS surface modification [27][28][29][32][33][34] . We applied PVA solutions with 87-90% and 99+% hydrolysis degrees on PDMS surfaces that were plasma oxidized under the same conditions (50 W for 1 min) and concluded that the former had a more profound effect on the PDMS surface chemistry both in the short and the long term (Figure 1a).…”

“…Our experimental data show that the PVA-treated PDMS surfaces retain their hydrophilicity in the long term. We leveraged PVA solutions with two distinct hydrolysis degrees (87-90% and 99+%) because these are widely used for surface modification in PDMSbased microfluidics 33,34 . Based on a wettability study, we found that PVA with a hydrolysis degree of 87-90% was more efficient in both the short and long term compared with PVA with a 99+% hydrolysis degree.…”

“…These procedures were developed to control the degree of biomolecule interaction with the PDMS substrate and not to modify the hydrophobicity of the surface with regards to droplet microfluidics. A combination of PVA and glycerol coating was immobilized on a plasma-treated PDMS microfluidic chip to encourage poly(L-lactic acid) microsphere generation 33 . However, this study relied on a continual supply of PVA during microsphere generation.…”

Microfluidic synthesis and post processing of non-spherical polymeric microparticles

“…Whereas the use of solution reactions to generate complex shapes of nano and micro structures almost seems serendipitous, microfluidics technology offers a unique route toward synthesizing such complex, monodisperse particles with predetermined size and shape with relative ease (Takasi and Takeshi 2010;Helgeson et al 2011;He et al 2011). Thus, microfluidics technology is receiving increasing attention for synthesizing customized particles with spherical or non-spherical morphology.…”

Mid-Infrared Spectrometer Using Opto-Nanofluidic Slot-Waveguide for Label-Free On-Chip Chemical Sensing

“…In the absence of a slot-structure, only the tail of guided waves (evanescent wave) could interact with analyte, and this configuration would significantly reduce the sensitivity of the device. To avoid absorption of lightwave by PDMS, which is a mid-IR absorptive between λ = 2.6 μm to λ = 4 μm, 38 we introduced an additional SiO 2 layer that conformally covers the Si−SiO 2 −Si waveguide to prevent direct contact between the SiO 2 slot-waveguide and the PDMS chamber. Figure 3 shows micrographs of the fabricated nanofluidic channels and mid-IR slot-waveguides obtained by scanning electron microscope (SEM).…”