Halloysite nanotubes (HNTs) are natural occurring mineral clay nanotubes that have excellent application potential in different fields. However, HNTs are heterogeneous in size, surface charge, and formation of surfacial hydrogen bond, which lead to weak affinity and aggregation at a certain extent. It is very important to modify the HNTs’ surface to expand its applications. In this review, the structural characteristics, performance, and the related applications of surface-modified HNTs are reviewed. We focus on the surface-modified variation of HNTs, the effects of surface modification on the materials and related applications in various regions. In addition, future prospects and the meaning of surface modification were also discussed in HNTs studies. This review provides a reference for the application of HNTs modifications in the field of new nanomaterials.

Halloysite nanotubes (HNTs), due to their unique structures and properties, may play an important role in biomedical applications. In vitro test is usually conducted as a preliminary screening evaluation of the hemocompatibility and cytotoxicity of HNTs for its short term consuming, convenience, and less expense. In this work, HNTs were processed with anticoagulated rabbit blood to detect its blood compatibility. The result of hemolysis test shows that the hemolysis ratios are below 0.5%, indicating nonhemolysis of HNTs. Plasma recalcification time suggests that HNTs are dose‐dependently contributing to blood coagulation in platelet poor plasma (PPP). The effect of platelet activation caused by HNTs was also examined by scanning electron microscopy (SEM). Meanwhile, HNTs were labeled with fluorescein isothiocyanate (FITC) to observe its intracellular distribution in A549 cells under confocal microscopy. CCK‐8 test and TUNEL test of HNTs at different concentration levels were performed in vitro, respectively. Therefore, the potential usage of HNTs in medicine may be very meaningful in oral dosing, dermal application, dental uses, or medical implants.

In this work, an environmentally friendly antibacterial composite was prepared by loading natural halloysite nanotubes (HNTs) with chlorhexidine gluconate (CG). Fourier transform-infrared spectroscopy and X-ray diffraction demonstrated that CG could be successfully loaded on HNTs without changing the crystalline structure of HNTs. In vitro drug release assay showed that CG could be released from HNTs in a sustainable manner and could last as long as about ten days. Inhibition zone test suggested that the new composite displayed significant bacterial killing activity. In addition, the composite was deposited on the surface of cotton fabric by dip-coat technique. Our results showed that the HNTs/CG composite could be distributed on the cotton fabric and possessed better thermal stability and hydrophilicity properties than raw cotton fabric. HNTs/CG-coated cotton fabric exhibited over 98% bacterial reduction of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and still showed over 90% antibacterial activity even after being washed 20 times. MTT test and animal skin irritation tests indicate that HNTs/CG-coated cotton was nontoxic to mouse fibroblast cells (L929) and gave no irritation to the rabbit's skin. Thus, HNTs/CG composite is a safe and promising antibacterial agent and has great potential application in the textile field.

The emergence of nanomedicine has enriched the knowledge and strategies of treating diseases, and especially some incurable diseases, such as cancers, acquired immune deficiency syndrome (AIDS), and neurodegenerative diseases. The application of nanoparticles in medicine is in the core of nanomedicine. Nanoparticles can be used in drug delivery for improving the uptake of poorly soluble drugs, targeted delivery to a specific site, and drug bioavailability. Early diagnosis of and targeted therapies for cancers can significantly improve patients’ quality of life and extend patients’ lives. The advantages of nanoparticles have given them a progressively important role in the nanodiagnosis and nanotherapy of common cancers. To provide a reference for the further application of nanoparticles, this review focuses on the recent development and application of nanoparticles in the early diagnosis and treatment of the three common cancers (lung cancer, liver cancer, and breast cancer) by using quantum dots, magnetic nanoparticles, and gold nanoparticles.