Extremely Uniform Graphene Oxide Thin Film as a Universal Platform for One‐Step Biomaterial Patterning

Abstract

Graphene oxide (GO) has proven to be a highly promising material across various biomedical research avenues, including cancer therapy and stem cell‐based regenerative medicine. However, creating a uniform GO coating as a thin layer on desired substrates has been considered challenging owing to the intrinsic variability of the size and shape of GO. Herein, a new method is introduced that enables highly uniform GO thin film (UGTF) fabrication on various biocompatible substrates. By optimizing the composition of the GO suspension and preheating process to the substrates, the “coffee‐ring effect” is significantly suppressed. After applying a special postsmoothing process referred to as the low‐oxygen concentration and low electrical energy plasma (LOLP) treatment, GO is converted to small fragments with a film thickness of up to several nanometers (≈5.1 nm) and a height variation of only 0.6 nm, based on atomic force microscopy images. The uniform GO thin film can also be generated as periodic micropatterns on glass and polymer substrates, which are effective in one‐step micropatterning of both antibodies and mouse melanoma cells (B16‐F10). Therefore, it can be concluded that the developed UGTF is useful for various graphene‐based biological applications.

Nano-sized graphene oxide coated nanopillars on microgroove polymer arrays that enhance skeletal muscle cell differentiation

“…GO have been used as composing materials for various bio-integrated platforms due to biocompatible characteristics and highly adhesive nature of GO [ 39 , 40 ]. To attach the C2C12 cells to the substrates stably and further control the myogenesis, GO sheets were coated on the substrates through a transfer technique, as previously reported [ 41 ]. The GO could be simply modified on the desired substrate via the drop-coating method.…”

Fabrication of Hydroxyl‐Group‐Rich Reduced Graphene Oxide Film and its Application for Electrochemical Detection of Hydrogen Peroxide

“…To eliminate this uniformity issue that may occur during thermal reduction, the UGTF was first fabricated on the electrode surface under the optimized conditions identified in our previous study. [31] Briefly, GO was spin-coated on an ITO substrate under thermal convection, followed by LOLP treatment. LOLP causes etching and smoothing of the GO film, resulting in the fragmentation of large-scale GO flakes (Figure S2, Supporting Information).…”

“…First, an extremely uniform graphene oxide thin film (UGTF) is formed on an indium tin oxide (ITO)coated glass substrate by means of sequential spin-coating in conjunction with low-oxygen concentration and low-electrical-energy plasma (LOLP) treatment, as reported previously. [31] Thereafter, mild annealing is performed at a low temperature with an ultrashort exposure time (10 s at temperatures <300 °C) (Figure S1, Supporting Information). We hypothesize that owing to the physical properties of UGTF, namely, extremely high uniformity and low thickness, it can be reduced rapidly, resulting in the recovery of conductance and retention of functional hydrophilic moieties.…”

Electrically controlled mRNA delivery using a polypyrrole-graphene oxide hybrid film to promote osteogenic differentiation of human mesenchymal stem cells

“…PPy is a stable material in conventional cultivation conditions and can retain high conductivity for a long period of time [32,33]. On the other hand, GO is a non-conductive carbon-based nanomaterial that possesses both hydrophilic groups (e.g., hydroxyl, epoxide, carbonyl, and carboxyl groups) and hydrophobic domains [34][35][36]. Owing to its distinct amphiphilic characteristics, GO is known to weakly absorb nucleic acids, including siRNAs, mRNAs, and single-strand DNAs, via π-π stacking and hydrogen bonding, and is thus suitable for mRNA loading [37][38][39][40].…”