Monolithic nano-porous polymer in microfluidic channels for lab-chip liquid chromatography

Abstract

In this paper, a nano-porous polymer has been integrated into the microfluidics device as on-chip monolithic liquid chromatography column for separation of chemical and biological samples. Monolithic nano-porous polymer (MNP) was formed and firmly grafted on the surface of the microfluidic channel. Neurotransmitters, 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptamine (serotonin, 5-HT), were successfully separated with the developed on-chip MNP column.

Fig. 1

Fabrication procedures of a TPE microfluidic device, (i) PDMS replica mould from the acrylate master mould, (ii) TPE pouring, (iii) peeling off the semi-cured TPE, (iv) bonding with the PET substrate, (v) PEEK unions attachment and the channel packing with MNP, and b poly(methyl acrylate) monolithic column packing in the channel, (i) introducing a photografting solution into a TPE channel, (ii) UV exposure through PET substrate, (iii) flushing the residual solution by flowing a methanol-based cleaning solution, (iv) introducing the poly(methyl acrylate) mixture solution, (v) UV exposure through PET substrate and (vi) flushing unreacted solutions using the cleaning solution

Fig. 2

The contact angle measurement of the grafting layer on PET substrate

Fig. 3

The poly(methyl acrylate) monolith a without and b with the grafting layer

Fig. 4

The poly(methyl acrylate) monolith column in the microfludic channel a, b without and c, d with the grafting layer. (b) and (d) shows the interface between the monolith and the surface of the microfluidic channel

Fig. 5

Packing efficiency test of the poly(methyl acrylate) monolithic TPE column without and without the grafting layer, a back pressure and b column permeability as a function of the flow rate

Fig. 6

Separation of neurotransmitters mixture at 150 µL/min using the poly(methyl acrylate) monolithic TPE column. [solutes: 5-HIAA and 5-HT(serotonin)]