Non-aggregating resorbable calcium phosphosilicate nanoparticles (CPNPs) are bioconjugated to targeting molecules that are specific for particular cells. The CPNPs are stable particles at normal physiological pH. Chemotherapy and imaging agents may be integrally formed with the CPNPs so that they are compartmentalized within the CPNPs. In this manner, the agents are protected from interaction with the environment at normal physiological pH. However, once the CPNPs have been taken up, at intracellular pH, the CPNPs dissolve releasing the agent. Thus, chemotherapeutic or imaging agents are delivered to specific cells and permit the treatment and/or imaging of those cells. Use of the bioconjugated CPNPs both limits the amount of systemic exposure to the agent and delivers a higher concentration of the agent to the cell. The methods and principals of bioconjugating CPNPs are taught by examples of bioconjugation of targeting molecules for breast cancer, pancreatic cancer, and leukemia.