Lotus Leaf-Inspired Bone Cement Particles with Ultrahigh Drug Encapsulation Capacity

Nowadays, interest is growing toward drug-loaded inorganic particles with high drug encapsulation capacity to treat bone disease. However, the conventional adsorption method and in situ coprecipitation method always encountered the problem of low drug encapsulation efficiency. The phenomenon of water droplet standing in a near-spherical shape with very small contact area on the lotus leaf inspires us to demonstrate a simple and green strategy to handle this issue. Briefly, the slurry containing bone cement powders, drug, and water is first dripped onto the superhydrophobic surface to form a microreactor, and then the drug will be encapsulated in the confined microreactor due to the self-setting reaction of the bone cement powders with water. Calcium sulfate hemihydrate (CSH), a kind of biocompatible and historical bone cement, is employed to prepare calcium sulfate dihydrate (CSD) bone cement particles. Two kinds of drugs acetaminophen and ibuprofen with different water solubility are further individually embedded into the CSD matrix to investigate the drug encapsulation and release behaviors. The results indicate that the CSD particles with tunable diameters can be easily prepared by changing the volume of the dispensing droplets. Most importantly, the drug encapsulation efficiencies can reach up to 91% for both the hydrophilic and the hydrophobic drug, which are the highest as compared with the other reported methods. It is also indicated that the drug release profiles can be finely controlled by the size of the CSD particles and the drug loading amount. Our strategy provides a novel pathway in the rational design of drug-loaded particles with ultrahigh drug encapsulation efficiency, which shows great advantages in the bone repairing applications