A holocellulose framework with anisotropic microchannels for directional assembly of copper sulphide nanoparticles for multifunctional applications

Abstract

Abstract A holocellulose framework (HCFW) with anisotropic microchannels, which is synthesized via a facile top–down strategy, is demonstrated to be an ideal anisotropic substrate to guide the directional assembly of CuS nanoparticles (CuS NPs) along the walls of microchannels. The oxygen-containing groups on the surface of HCFW and its abundant low tortuosity of channels contribute to the high loading (ca. 22.7 wt%) and homogeneous dispersion of CuS NPs as well as the fast outdiffusion of cytotoxic substances (such as Cu(I)/Cu(II)), hence endowing the composite with an outstanding antibacterial activity which achieves approximatively 100% of growth inhibition ratios for Escherichia coli and Staphylococcus aureus and extremely low minimal inhibitory concentrations of 8 μg mL−1 for these both bacteria. For drug delivery application, the release of doxorubicin hydrochloride (DOX) from CuS NPs@HCFW is well regulated by solution pH. A maximum cumulative release capacity of DOX (78.3%) is achieved at pH of 2.2. The cancer therapy capability of DOX-loaded CuS NPs@HCFW is also validated in vivo. Moreover, CuS NPs@HCFW has a strong antibiotic removal ability (~100% complete removal of ciprofloxacin within 120 min) by virtue of adsorption and catalytic oxidation in the presence of potassium peroxymonosulfate. These inspiring results not only indicate the high potential of CuS NPs@HCFW for antibacterial, pH-responsive drug delivery and antibiotic removal applications, but also provide a new sight for the development of novel anisotropic composites by using anisotropic HCFW for more extensive uses.