2, CECAD Imaging Facility, Cologne, , Germany
3, Max Planck Institute for the Science of Light, Erlangen, , Germany
For the interconnection between a synthetic material and living matter, hollow mesoporous silica particles have gained intense attention due to their high biocompatibility and stability in biological milieu. Related to their inner core they exhibit a high loading capacity suitable for drug delivery vehicles. In this work ellipsoidal hollow mesoporous silica (HMS) capsules were synthesized via hard template method, using ellipsoidal hematite particles as core material. The hematite core was synthesized through a solvothermal process, coated with a silica sol followed by acidic leaching, leading to HMS capsules. The porosity of as-prepared particles was analyzed using nitrogen adsorption-desorption method revealing a pore size of circa 4 nm and a high surface area of 308.8 m2/g. To determine cytotoxicity, cell viability test (MTT) towards human kidney cells (HEK293) was performed clearly demonstrating that no reduction of cell viability was observed even at high concentrations of 100 µg/ml. Uptake studies using confocal microscopy were carried out using human cervical cancer cells (HeLa) which could show the successful internalization over a period of 24 hours. For testing their capability as drug delivery vehicle, a hydrophilic antibiotic (ciprofloxacin) and a hydrophobic anticancer (curcumin) compound were loaded and a pH dependent release under physiological conditions at 37°C was monitored via UV-Vis spectroscopy. Ciprofloxacin-loaded HMS particles with a concentration of 10 µg/ml were also tested towards gram negative bacteria (E.coli) revealing a complete growth inhibition over 18 hours. This study demonstrates the suitability of as-prepared hollow silica capsules as drug delivery vehicles for a broad range of drugs.