Advances and Challenges of Fluorescent Nanomaterials for Synthesis and Biomedical Applications.

With the rapid development of nanotechnology, new types of fluorescent nanomaterials (FNMs) have been springing up in the past two decades. The nanometer scale endows FNMs with unique optical properties which play a critical role in their applications in bioimaging and fluorescence-dependent detections. However, since low selectivity as well as low photoluminescence efficiency of fluorescent nanomaterials hinders their applications in imaging and detection to some extent, scientists are still in search of synthesizing new FNMs with better properties. In this review, a variety of fluorescent nanoparticles are summarized including semiconductor quantum dots, carbon dots, carbon nanoparticles, carbon nanotubes, graphene-based nanomaterials, noble metal nanoparticles, silica nanoparticles, phosphors and organic frameworks. We highlight the recent advances of the latest developments in the synthesis of FNMs and their applications in the biomedical field in recent years. Furthermore, the main theories, methods, and limitations of the synthesis and applications of FNMs have been reviewed and discussed. In addition, challenges in synthesis and biomedical applications are systematically summarized as well. The future directions and perspectives of FNMs in clinical applications are also presented.

Adsorption behavior of epirubicin hydrochloride on carboxylated carbon nanotubes.

The aim of this study was to understand the interaction between carboxylated carbon nanotubes (c-CNTs) and anticancer agents and evaluate the drug-loading ability of c-CNTs. We prepared carboxylated multi-walled carbon nanotubes (c-MWNTs) with nitric acid treatment, then evaluated the adsorption ability of c-MWNTs as adsorbents for loading of the anticancer drug, epirubicin hydrochloride (EPI), and investigated the adsorption behavior of EPI on c-MWNTs. Unmodified multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) were included as comparative adsorbents. The results showed that carbon nanotubes were able to form supramolecular complexes with EPI via π-π stacking and possessed favorable loading properties as drug carriers. The Freundilich adsorption model was successfully employed to describe the adsorption process. Because of the high surface area and hydrogen bonding, c-MWNTs' adsorption efficiency was the highest and the most stable and their drug-loading capacity was superior to that of MWNTs. With the increase of pH, the adsorption capacity of EPI on the c-MWNTs increased. Low-temperature facilitated the adsorption. More rapid EPI adsorption rate and higher drug-loading ability were observed from c-MWNTs with smaller diameter. Moreover, the adsorption kinetics of EPI on c-MWNTs could be well depicted by using the pseudo-second-order kinetic model.