**7.2 Diamond**

One such substrate material that has recently been gaining in popularity is thin-film diamond. In early reports, very low toxicity was observed when diamond particles were injected as a suspension into live animals. Subsequently, it was established that diamond films as a cell culture substrate can successfully support a wide range of adherent cells. One of the most important properties of the diamond film is that it is bioinert, no coagulation and no inflammatory reactions [11]. One of its further advantages is the controllable electrical conductivity and the possibility of surface patterning.

### **7.3 Graphene oxide (GO)**

Graphene oxide (GO) is a unique material that can be viewed as a single monomolecular layer of graphite with various oxygen containing functionalities such as epoxide, carbonyl, carboxyl and hydroxyl groups. The reduced GO forms (rGO) which contains residual oxygens, some structural defects and other heteroatoms make it more functionally. Nevertheless, since rGO can be made as a thin film from an aqueous dispersion of GO in water and has moderate conductivity, it is attractive for use in electronic devices. In addition to being components in electronic devices, GO and rGO have been used in nanocomposite materials, polymer composite materials, energy storage devices, biomedical applications and catalysis and as a surfactant [12].

One use of GO in the biomedical field is as a component in drug delivery. Functionalized nanographene oxide (nGO) has been used in several studies on targeted delivery of anticancer drugs. Polyethylene glycol (PEG)-functionalized nGO with a champotecin derivative (nGO-PEG-SN38), adsorbed onto the surface, was used as a water- and serum-soluble source of the drug. nGO-PEG-SN38 was shown to be three orders of magnitude more effective than irinotecan (CPT-11), an FDAapproved SN38 prodrug, at reducing the cell viability of human colon cancer cell lines HTC-116 [13]. GO has also been used as a fluorescence quenching material in biosensors which utilise the fluorescence resonance energy transfer (FRET) effect.

### **8. Conclusions**

Nanostructures in their different forms, thin films, matrices, etc., have a wide range of possible utilizations due to their small—comparable to molecules—sizes, their physicochemical activity, etc. Applications/manufacturing methods are presented in this chapter focusing on making interest in life and medical sciences.

*Prologue: Thin-Film Synthesis and Application for Medical and Biological Use DOI: http://dx.doi.org/10.5772/intechopen.84968*
