(335d) Bio-Microfluidics Based on Non-Swelling Hydrogels

Hydrogels are the more biological relevant
materials than polydimethylsiloxane (PDMS) for microfluidics fabrication.
However, it is impossible to construct the high-precise and size-stable
microchannels inside hydrogels, because the poor mechanical strength and
inherit swelling behavior of hydrogels gradually deform the as-prepared
structure of microchannels under varying environments. To obtain a hydrogel
microfluidic that is able to keep the microchannel sizes exactly same as design,
we propose that non-swelling hydrogel with high mechanical strength is
required. Here we fabricate
the hydrogels by covalently cross-linking of di-acrylated Pluronic F127
(F127-DA). As shown in Figure 1, the F127-DA hydrogel is non-swelling at 37¡ãC in aqueous solution.

Figure
1 Swelling of F127-DA hydrogels at different temperature.

Attributed to the non-swelling property and
high strength of the F127-DA hydrogel, it is easily to achieve the microfluidics
with different channels that present high resolution and exactly same dimension as the designed molds for casting. The obtained
microfluidics are extremely thermo-stable even under autoclaving (Figure 2) and
resist to degradation during long-term incubation, which guarantees the well
retained channel structures in manufacture and application processing.

Figure
2 Morphology of hydrogel chips at different temperature.

As an exemplification, endothelial cells
are cultured in the microfluidic to construct a vessel-on-chip, and the
endothelial functions are detected to verify the feasibility as cell culture
chips (Figure 3).

Figure
3 Endothelial cells inside the chip channel after 6 days perfusion. Red: VEGF;
Green: F-actin; Blue: DAPI.