Departmental Seminar – Alexander Jesmer – Chemical Biology Ph.D. Seminar
Jul 28, 2022
1:30PM to 2:30PM
Date(s) - 28/07/2022
1:30 pm - 2:30 pm
Title: Simplemethods for the synthesis of low-fouling, biofunctional polymer coatings
Date: Thursday,July 28, 2022
Location: ABB 164
Host: Dr.Ryan Wylie
Materials in contact with thebiological milieu nonspecifically adsorb proteins which may lead to unwantedcell adhesion and responses or hinder device performance. These interactionslead to complications in ~3% of implant surgeries and prevent multi-day functionof biosensors in complex media. Thus, resistance to these nonspecificinteractions is critical to improve the performance of many implantedbiomaterials and biosensing surfaces.
Thin film coatings of antifoulingpolymers are one of the leading methods for reducing nonspecific interactions,where composition and grafting density are the principal determinants ofcoating performance. For applications requiring specific bioactivity, such assensors, the polymer coating must be both antifouling and functionalizable withcapture ligands. Tethered polymer coatings can be made by surface initiatedpolymerization (“graft-from”) which results in higher density coatings, but thecomplex fabrication limits commercialization and capacity for functionalization.Simpler “graft-to” procedures, where pre synthesized polymers are immobilizedto a surface, are more amenable to translation but suffer from inferiorantifouling properties due to limited densities. New fabrication methods aretherefore required to improve both graft-to and graft-from coatings.
Herein, we developed new and easy to manufacturegraft-from and graft-to procedures to overcome the limited functionality ofgraft-from surfaces and the poor polymer density of graft-to surfaces, whilesimultaneously producing label-free biosensors. Graft-from bilayers of varyingpolymer density were produced in one-pot to achieve low-fouling yet highlyfunctionalizable surfaces. Graft-to surfaces were enhanced by combining polymergrafting with expandable or shrinking medical devices to improve antifoulingproperties and biosensor coatings.
First, we describe the “graft-from” based, pHcontrolled, one-pot production of two-layer poly(carboxybetaine methacrylamide)(pCB) brushes composed of a low-fouling dense layer and a high-loading lowerdensity layer where capture ligand immobilization was improved 6-fold comparedto a single high density layer for biosensor applications. Secondly, towardsimproving fouling of “graft-to” surfaces, the first demonstration ofGraft-then-Shrink, where polymers are grafted to expandable materials wasexplored. Graft-then-Shrink was first applied to a stretched, gold coated,polystyrene substrate coated with thiol-terminated pCB. The thermo-shrinkingincreased polymer surface coating content for enhanced antifouling propertiesand produced micro/nano gold wrinkles to generate a novel LSPR active surface,which was used as a biosensor. Graft-then-Shrink was then extended toelastomeric materials, where thiol terminated pCB and poly(oligo(ethyleneglycol)) methyl ether methacrylate polymers were grafted onto solvent swollensilicone via thiol-maleimide click chemistry, producing strongly antifoulingmaterials.
Together, these methods canimprove antifouling properties of implantable medical devices and has resultedin the development of a new, translatable low-fouling LSPR biosensor for thedetection of biomolecular interactions.