Chemical vapor deposition (CVD) is among the most utilized techniques to fabricate single-layer graphene on a large substrate. However, the substrate is limited to very few transition metals like copper. On the other hand, many applications involving graphene require technologically relevant substrates like semiconductors and metal oxide, and therefore, a subsequent process is often needed to transfer CVD to the new substrate. As graphene is fragile, a supporting material such as a polymer film, is introduced during the transfer process. This brings unexpected challenges, the biggest of which is the complete removal of this support material without contaminating graphene. Numerous methods have been developed, each having advantages and drawbacks. This review will first introduce the classic transfer method using poly(methyl methacrylate) (PMMA) as the support material. The operating procedure and issues of PMMA residuals will be discussed. Methods to minimize/eliminate contamination will be presented, together with alternative approaches that do not require the use of PMMA.

Carbohydrates constitute the most abundant organic matter in nature, serving as structural components and energy sources, and mediating a wide range of cellular activities. The emergence of nanomaterials with distinct optical, magnetic, and electronic properties has witnessed a rapid adoption of these materials for biomedical research and applications. Nanomaterials of various shapes and sizes having large specific surface areas can be used as multivalent scaffolds to present carbohydrate ligands. The resulting glyconanomaterials effectively amplify the glycan-mediated interactions, making it possible to use these materials for sensing, imaging, diagnosis, and therapy. In this review, we summarize the synthetic strategies for the preparation of various glyconanomaterials. Examples are given where these glyconanomaterials have been used in sensing and differentiation of proteins and cells, as well as in imaging glycan-medicated cellular responses.