Grafting of oligodeoxynucleotide hairpin onto membrane surface to improve its anti-fouling performance

• An oligodeoxynucleotide was first grafted onto PAN membrane.
• The grafted membranes demonstrated an improvement in anti-fouling capacity.
• The adsorption of protein on membrane was controllable by adjusting the pH values.

Polyacrylonitrile (PAN) membrane has been widely used in traditional ultrafiltration processes. However, the nonspecific adsorption of proteins on PAN membrane reduces the flux and increases the operation cost by requiring extra process of cleaning. Generally, hydrophilic and electrically neutral reagents such as polyzwitterionic materials were used to improve its anti-fouling performance. In the present study, a negatively charged oligodeoxynucleotide with a hairpin structure was first grafted onto PAN membrane to improve its anti-fouling capacity. The oligodeoxynucleotide modified (OPAN) membranes were characterized in terms of chemical composition, morphology, and surface properties indicating that the oligodeoxynucleotide could successfully be bonded onto the PAN membrane. The anti-protein-fouling properties of the membrane were tested using static protein adsorption and dynamic-filtration experiments. The experimental results indicate that the flux ecovery rate of the OPAN membrane was much higher than that of the pure PAN membrane. The improved anti-fouling performance of the membrane is suggested to be attributed to the steric hindrance and electrostatic repulsion between the oligodeoxynucleotides and the proteins.

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