In recent decades, drug development has advanced dramatically, enabling treatment for previously untreatable diseases. Many of these new drugs, called biologics, resemble proteins and DNA (coding system) naturally occurring in the body. However, since bacteria and viruses produce similar molecules, the immune system is trained to eliminate foreign proteins and DNA. This defense protects us from infection but can also reduce the effectiveness of biological drugs. Therefore, for biologics to work they need to avoid the immune system and reach the target cells. One solution is using small nanocarriers to protect and deliver the drugs. My PhD project is about investigating calcium phosphate nanoparticles as drug carriers for biological drugs to be able to treat neuroblastoma and glaucoma. But the intention is that the nanocarrier system can, by modest modification, be applied to deliver similar drugs treating various diseases.