Point-of-care Testing：Hybrid paper-based digital microfluidic detection chip
Here, we demonstrate fabrication of paper-based EWOD devices using cellulose paper as substrate and paraffin wax as dielectric hydrophobic layer by a simple pressing treatment for the cellulose paper and melting or spray-coating of paraffin wax.
We optimized the key fabrication parameters according to the surface morphology and hydrophobicity of the obtained wax film, including the pressing pressure, thermal annealing temperature and amount of paraffin wax. Moreover, the EWOD devices fabricated by the spray-coating method demonstrate larger contact angle changes but with smaller contact angle hysteresis under DC electric field when compared with the devices fabricated by the melting method.
Figure1. We fabricated paper-based EWOD devices using cellulose paper as substrate and paraffin wax as dielectric hydrophobic layer, which have been widely used in fabrication of continuous-flow µPAD. The cellulose paper was firstly densified via being pressed under different pressures to reduce the surface roughness and internal void volume. The paraffin wax film was fabricated via two different approaches, including melting method and spray-coating method followed by thermal annealing treatment.
Figure2. BNP quantitative detection of HPDMF chip.
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