Yuji Higaki,* Riku Furusawa, Takefumi Otsu, Norifumi L. Yamada
"Zwitterionic Poly(carboxybetaine) Brush/Albumin Conjugate Films: Structure and Lubricity"
Langmuir, in press DOI: 10.1021/acs.langmuir.2c01040
“What is the zwitterionic polymer brush/protein conjugate thin film structure and the impact of protein conjugation on the tribological properties?”
We investigated a facile procedure to conjugate proteins to a zwitterionic poly(carboxybetaine) (PCB) brush, and the adaptable wetting performance, nonuniform structure, and lubrication properties of the PCB brush/BSA conjugate films in PBS were addressed. We achieved to produce PCB brush/BSA conjugate films by carbodiimide chemistry and found out an optimum reaction condition by screening. The PCB brush/BSA conjugate films exhibit adaptable interfacial properties due to the amphiphilic nature of BSA. The conjugated BSAs were localized at the liquid side of the conjugate film, and hardly located inside. The BSA conjugation reduced the water content at the top layer, while the carpet PCB brush layer was well-swollen identical to before conjugation. The PCB brush/BSA conjugate films showed improved lubricity in the boundary lubrication regime probably due to the decrease in contact area caused by the raise of elastic modulus through BSA conjugation and electrostatic repulsive interactions. This is the first report shedding light to the nonuniform structure of zwitterionic polymer brush/protein conjugate films in buffer solution and coupled the nonuniform swollen structure with the lubrication performance, then could be a model system for investigating zwitterion/protein composite interfaces, and valid for the design of biomedical apparatus which require lubrication in vivo.
Riku Furusawa was in charge of this project. He has a good mentality to be disciplined and work independently. I’m pleased to have him as a member of the start-up team. He has instilled discipline in our laboratory and fostered a culture of sincere efforts for advances, and the achievements still work on today. He was also helpful to develop the network infrastructure of our laboratory. I wish him all the best in his future life in the company employed.
I appreciate all coauthors who participated in this project. I sincerely acknowledge Prof. Otsu for collaboration in tribology experiments, and Prof. Yamada for management and support in NR experiments.
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