Yan‐Yan Song

Amphiphilic TiO(2) nanotube arrays are fabricated by a two-step anodization procedure combined with hydrophobic monolayer modification after the first step. These tubes can be used as biomolecular carriers, where the outer hydrophobic barrier provides an efficient cap against drug leaching to the environment. By utilizing the photocatalytic ability of TiO(2), a precisely controlled removal of the cap and a highly controlled release of the hydrophilic payload (drug) can be achieved.

We have successfully sculptured a variety of copper films with open interconnected macroporous walls and nanoparticles using hydrogen bubbles as the dynamic template. In this process, the hydrogen bubbles arising from the electrochemical reduction of H+ in the deposition process functioned as the dynamic template for metal electrodeposition. Cu was electrodeposited and grew within the interstitial spaces between the hydrogen bubbles to form a macroporous film of Cu nanoparticles on the substrate, showing a typical integration of micro−nanostructure. The pore diameters and wall thickness of the porous copper films were successfully tailored by adjusting the concentration of the electrodeposition electrolyte, the applied current density, and the concentration of the surfactant (cetyltrimethylammonium bromide, CTAB). Water contact angle measurements showed that the hydrophobicity of the prepared porous structures could be tuned by changing the pore size and wall thickness.

In biomedical applications, polyethylene glycol (PEG) functionalization has been a major approach to modify nanocarriers such as nano-graphene oxide for particular biological requirements. However, incorporation of a PEG shell poses a significant diffusion barrier that adversely affects the release of the loaded drugs. This study addresses this critical issue by employing a redox-responsive PEG detachment mechanism. A PEGylated nano-graphene oxide (NGO-SS-mPEG) with redox-responsive detachable PEG shell is developed that can rapidly release an encapsulated payload at tumor-relevant glutathione (GSH) levels. The PEG shell grafted onto NGO sheets gives the nanocomposite high physiological solubility and stability in circulation. It can selectively detach from NGO upon intracellular GSH stimulation. The surface-engineered structures are shown to accelerate the release of doxorubicin hydrochloride (DXR) from NGO-SS-mPEG 1.55 times faster than in the absence of GSH. Confocal microscopy shows clear evidence of NGO-SS-mPEG endocytosis in HeLa cells, mainly accumulated in cytoplasm. Furthermore, upon internalization of DXR-loaded NGO with a disulfide-linked PEG shell into HeLa cells, DXR is effectively released in the presence of an elevated GSH reducing environment, as observed in confocal microscopy and flow cytometric experiments. Importantly, inhibition of cell proliferation is directly correlated with increased intracellular GSH concentrations due to rapid DXR release.