Significantly improving the colloidal stability of selenium disulfide in water and antifungal activity by using palygorskite clay

Abstract

The easy settling characteristics of selenium disulfide particles result in poor drug efficacy and user experience with the products. Here, four distinct ratios of nanohybrids were obtained by introducing palygorskite clay into selenium disulfide particles. The colloidal stability and antifungal ability of the hybrids were evaluated. The results show that as the palygorskite content in the hybrid increases, its colloidal stability initially exhibits a significant enhancement, followed by a subsequent weakening, reaching the optimal ratio of selenium disulfide to palygorskite at 1:3 (hybrid-25). The results of particle size, zeta potential, and contact angle indicate that colloid stability is mainly determined by the thickness of the particle hydration shell and the intensity of Brownian motion, and is basically independent of the surface charge. The SEM, TEM, XRD, FTIR, and XPS results reveal the formation mechanism of the hybrid, which first forms a package of palygorskite nanorod crystals on the surface (shallow) area of selenium disulfide particles through grinding, and then achieves complete and uniform hybridization of the two through a melting-impregnation method, which results in a leap from micrometer to nanometer. Selenium disulfide mainly exists on the surface of palygorskite crystals and in nanochannels, where selenium strongly interacts with O in SiO and AlO. The hybrid-25 exhibits excellent antifungal ability against Malassezia furfur (minimum inhibitory concentration of 780 μg mL⁻¹) and significantly less hair damage than commercially available selenium disulfide lotion. In short, the SeS₂@palygorskite nanohybrid exhibits excellent colloidal stability in water and satisfactory antifungal ability, making it a promising novel antifungal drug for the treatment of dandruff.