A novel chemical hydrogel was facilely achieved by coupling 1,4-phenylenebisdiboronic acid modified halloysite nanotubes (HNTs-BO) with compressible starch. The modified halloysite nanotubes (HNTs) and prepared hydrogel were characterized by solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscope (TEM). The linkage of B-C in the hydrogel can be degraded into B-OH and C-OH units in the presence of HO and result in the degradation of the chemical hydrogel. Pentoxifylline was loaded into the lumen of the HNTs-BO, and then gave the pentoxifylline-loaded hydrogel. The drug release profile shows that it was no more than 7% dissolved when using phosphate buffer solution (PBS) as the release medium. Notably, a complete release (near 90%) can be achieved with the addition of HO ([HO] = 1 × 10 M), suggesting a high HO responsiveness of the as-formed hydrogel. The drug release results also show that the "initial burst release" can be effectively suppressed by loading pentoxifylline inside the lumen of the HNTs rather than embedding the drug in the hydrogel network. The drug-loaded hydrogel with HO-responsive release behavior may open up a broader application in the field of biomedicine.

A novel fluorescence probe based on modified halloysite nanotubes (HNTs) by using 1-pyrenylboronic acid selectively grafted onto the inner surface of lumen was successfully achieved. The solid-state nuclear magnetic resonance ((13)C and (11)B), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) confirmed that the boronic acid group only binds to alumina at the tube lumen and does not bind the tube's outer siloxane surface. The modified HNTs (HNTs-PY) inherit the spectroscopic properties relating to the pyrene units. Interestingly, the established Al-O-B linkage gives the H2O2-sensitivity to pyrene grafted tubes. HNTs-PY exhibits a highly specific "turn-off" response for hyperoxide over other reactive oxygen species (ROS) and oxidative ions owing to their chemoselective boronate-to-phenol switch. The "turn-off" response can even be tracked when the additional amount of H2O2 was limited to 1 × 10(-6) mol. Thus, the selective modification method under mild conditions for the design of novel organic-inorganic hybrid fluorescence probe may open up a broader application as well as for identification and diagnosis.

Polyphosphonium was facilely grafted onto HNTs in an aqueous phase by a one-step method initiated by Ce(iv) at a mild temperature.

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