One-step fabrication method of non-fouling amine-functionalized polyethylene glycol thin film using a single precursor through plasma-enhanced chemical vapor deposition

Fabrication methods to produce an amine-functionalized surface have been widely investigated as it is a promising substrate for biological studies, owing to its ability to stably immobilize various biomolecules. In this study, a biocompatible amine-functionalized polyethylene glycol (aPEG) thin film was fabricated by using plasma-enhanced chemical vapor deposition (PECVD) to overcome the disadvantages of the conventional wet process. A functionalized PEG diamine was used as a single precursor to simplify the fabrication process, and the relationship between the surface functional group density and the plasma power was investigated. Also, the surfaces of the functionalized thin films were quantitatively analyzed to determine the optimal fabrication condition that yields the most excellent surface amine density. The non-fouling resistance of the aPEG thin film and its applicability for biological applications was demonstrated by successfully immobilizing the matrix metalloproteinase-7 (MMP-7) enzyme, which is a well-known biomarker for cancers, with minimal non-specific adsorption (NSA). Our fabrication method was further applied to the modification of rather challenging substrates, including carbon paper, polyethylene terephthalate (PET) film, silicon wafer, polyvinylidene fluoride (PVDF), and successful modification was confirmed by the results of time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis. It is expected that our fabrication method can enable applications of the functionalized thin film in bioscience by presenting a versatile surface modification technique for deposition of biocompatible material onto various substrates, which can be potentially used in disease diagnosis, medical implants, and bioengineering.