Amphiphilic diblock copolymers as functional surfaces for protein chromatography

Abstract

Stationary phase plays a crucial role in the operation of a protein chromatography column. Conventional resins composed of acrylic polymers and their derivatives contribute to heterogeneity of the packing of stationary phase inside these columns. Alternative polymer combinations through customized surface functionalization schemes which consist of multiple steps using static coating techniques are well known. In comparison, it is hypothesized that a single-step scheme is sufficient to obtain porous adsorbents as stationary phase for tuning surface morphology and protein immobilization. To overcome the challenge of heterogeneous packing and ease of fabrication at a laboratory scale, a change in the form factor of separation materials has been proposed in the form of functional copolymer surfaces. In the present work, an amphiphilic, block copolymer, poly(methyl methacrylate-co-methacrylic acid) has been chosen and fully characterized for its potential usage in protein chromatography. Hydrophilicity of the acrylic copolymer and abundance of carboxyl groups inherently on the copolymer surface have been successfully demonstrated through contact angle measurements, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) studies. Morphological studies indicate presence of a microporous region (nearly 1 to 1.5 µm pore size) that could be beneficial as a cation exchange media as part of the stationary phase in protein chromatography.

Template-assisted fabrication of moon-shaped channels for protein breakthrough analysis

“…With varying ACP concentration from 5 to 15% (w/v), it was interesting to observe that micropore size also varied from large pores to smaller pores (Figure 10 and image analysis of the SEM images wherever possible). It was consistent with the observations on a microporous region recently reported with ACP surface (or ACP-modified PDMS surface) by our research group [26].…”

“…Prerequisites for this process include preparation of (a) different concentrations (in %(w/v)) of acrylic copolymer solution (ca. 0.5 g poly(methyl methacrylate-co-methacrylic acid) dissolved in 5 ml tetrahydrofuran (THF) for 10%(w/v)) [26] and leave it undisturbed after initial mixing ∼ 5 to 6 hours for complete dissolution and (b) PDMS microchannel (170 μ m) using the templatebased micromolding method, as mentioned in the earlier section. 5 M sodium hydroxide solution was then passed through the microchannel at an inlet flow rate of 10 μ g ml −1 for about 15 to 20 minutes using syringe pump (NE-300, New Era Pump Systems, USA).…”

“…From electron microscopy and preparation of samples with 45 o section cut, by our research group [26].…”