Surfactant Assisted Hydroxyapatite Nanoparticles: Drug Loading and In Vitro Leaching Kinetics and Antimicrobial Properties

In the present investigation, extremely fine Hydroxyapatite (HAP) powder was prepared through chemical precipitation technique under the influence of a nonionic surfactant (Brij 35-Polyoxyethylene lauryl ether). The samples were sintered at 800 °C to obtain highly pure HAP phase. The functional group present in the HAP powder was confirmed by using Fourier transform infra-red (FTIR) spectroscopy. The change in Phase transformation, the crystallite size and the percentage of crystallinity of the synthesized sample were studied by X-ray diffractometer technique. The Field Emission Scanning Electron Microscope (FESEM) and High-resolution transmission electron microscopy (HRTEM) were used for the structural analysis of porous rod-shaped HAP crystal. Further, drug loading and In Vitro leaching kinetics were conducted for antibiotics-ciproflaxin (CPF). Antimicrobial activity against S. aureus (Gram-positive bacterium) and E. coli (Gram-negative bacterium) was executed for pure HAP as well as for drug loaded HAP.

Preparing stable pigment dispersion utilizing polyoxyethylene lauryl ether as dispersant

Purpose This study aims to evaluate the use of polyoxyethylene lauryl ether (PLE) as a dispersant in the preparation of novel pigment dispersion with enhanced dispersion ability, which can find application in the printing industry. Design/methodology/approach To obtain a good dispersion, PLE was used as a dispersant in pigments dispersion. The colloidal and rheological properties of the PLE-based dispersion, such as particle distribution, zeta potentials and apparent viscosity were evaluated. Findings The particle sizes of the pigment dispersions were within the range of 150 to 200 nm. The measurement of zeta potentials varied between −24 to −32 mV, revealing a strong surface charge interaction between pigments and PLE. Subsequently, its stability to high-speed centrifuge and freeze-thaw treatment was carefully investigated. To demonstrate the coverage of pigment particles by PLE, thermogravimetric analysis was carried out. Moreover, X-ray diffraction was used to disclose the combined impacts of PLE and ultrasonic power on the crystal structures of the pigments. Finally, the coloring performance and leveling properties of pigment dispersions on cotton substrates were evaluated by measuring their K/S values (color strength), rub and color fastness properties, which possessed good results. Research limitations/implications The dispersant used is incompatible with strong oxidizing agents and strong bases. More so, modification to improve its dispersion properties can be studied. Practical implications The use of PLE as a dispersant could be readily used in pigment dispersion processes and other suitable applications. PLE could also be used as a co-surfactant in synergy with other surfactants or dispersants in the dispersion process. Originality/value The use of PLE in pigment dispersion as well as investigating its coloring properties on cotton fabric is novel and can find various applications in the dying, printing and coating industry.