Diverse material platforms have been applied to diagnostics, drug delivery, and therapeutics.

The scale of those materials ranges from nanometers to micrometers, which is determined from the required properties for specific applications. Nano-sized materials have a similar size compared to the biological molecules such as proteins, DNA, and intracellular molecules, leading to their use as an efficient cargo for the intracellular delivery. Micron sized material platform has larger than the cells and could encapsulate the small molecules, proteins and even cells to deliver to specific local tissues. Macro-scale materials with a millimeter size-regime act as a depot of drug and even smaller sized material platforms for controlled release and actuation. In this talk, engineering of several material platforms with different scales will be described to reveal their uses in controlled drug and cell delivery, and in situ manipulation of endogenous cells for the potential application to the treatment of diseases.