The past decade has witnessed a growing interest in the application of nanotechnology to medicine. A major focus in this field is the design and engineering of particles for targeted therapy and diagnostics, as particles can facilitate high payloads, prolong the circulation time of drugs, improve drug targeting and solubility, and provide controlled-release of the therapeutics into the bloodstream or targeted tumor tissues. The presentation will cover our research on the development of engineered particles for cardiovascular disease, tumour targeting, HIV and drug delivery to the inner ear. Various assembly strategies to generate multifunctional and responsive particles that target, stimulate or distort cells for therapeutic delivery will be discussed. Recent studies on the development of nanostructured particles for efficient cargo encapsulation, triggered release and antibody-mediated targeting will also be highlighted. It will be shown that engineered particles with well-controlled physicochemical properties can be used to uncover several key principles that govern particle-cell interactions, knowledge that is critical for future development of particle carriers for biomedicine applications.