Abstract
Polybutylene terephthalate (PBT) nonwovens were successfully grafted with poly(glycidyl methacrylate) (polyGMA) using a heat induced grafting approach with the thermal initiator benzoyl peroxide (Bz2O2). This grafting method resulted in complete, uniform, and conformal grafted layers around the PBT fibers that could be further functionalized as ion exchangers for protein capture. Protein binding capacities as high as 200 mg/g were achieved for ion exchange PBT nonwovens grafted to 20% weight gain using this heat induced grafting method. Compared to UV grafted polyGMA PBT nonwovens, the rates of protein adsorption are several times faster for the heat grafted polyGMA PBT nonwoven, reaching equilibrium within minutes; UV grafted polyGMA ion exchange PBT nonwovens require hours to reach equilibrium. This indicates that polyGMA grafts formed by heat induced grafting are thinner, and therefore more dense, than UV grafted layers with the same % weight gain. To further investigate the structural differences between the two grafting methods, targets of various molecular weights (ATP, lysozyme, BSA, hIgG) were adsorbed to the materials. Increasing the target size resulted in a decrease of target molecules bound for both grafting methods. However, the heat grafted nonwovens exhibited a much stronger dependence of protein molecular weight on protein capture, indicating that heat induced grafting results in a polyGMA layer that has a smaller free volume between chains available for protein binding compared to the UV grafting method. Protein adsorption isotherms for the two grafting methods confirmed that both methods resulted in similar strengths of protein binding, with dissociation constants on the order of Kd = 10–6 M which is consistent with ion exchange binding on polymer brush networks. Heat grafted polyGMA ion exchange PBT nonwovens showed excellent protein binding and elution.
Highlights
Nonwovens fabric membranes, broadly defined as web structures in which the random fibers and filaments are bonded together mechanically, thermally, or chemically, are used in numerous applications from medicine to electronics.[1]
Equilibrium binding capacities as high as 200 mg/g were observed for the heat grafted nonwovens grafted to 24% weight gain functionalized as a cation exchanger for binding of hIgG
Kinetics of protein adsorption indicated that the heat grafted nonwovens were capable of achieving equilibrium binding on the order of minutes compared to the UV grafted nonwovens that required several hours to reach equilibrium
Summary
Broadly defined as web structures in which the random fibers and filaments are bonded together mechanically, thermally, or chemically, are used in numerous applications from medicine to electronics.[1] Surface initiated polymerization of nonwoven fabric membranes is a useful technique for introducing a thin polymer layer with substantially different surface properties on the material being grafted.[2,3] In bioseparations, polymer grafting has been used to functionalize polyolefin and polyester based nonwoven fabric membranes to create high capacity protein capture devices.[4−10] Polyolefin and polyester are inexpensive thermoplastic polymers commonly used in high-rate nonwoven manufacturing technologies. A direct comparison is drawn between the heat induced and the UV induced polyGMA grafting of PBT nonwovens since UV grafting is the primary methodology for vinyl grafting of polyester and polyolefin membranes and has been investigated extensively for grafting of polyGMA onto PBT nonwovens.[4,9,10,13] For these reasons, in this investigation, it is the benchmark for comparison of the heat grafted PBT nonwovens regarding graft morphology, chemical functionalization, protein binding capacity, thermodynamics of protein adsorption, and binding kinetics
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
