Dendrimer-based drug and imaging conjugates: design considerations for nanomedical applications

Dendrimers are members of a versatile, fourth new class of polymer architecture (i.e. dendritic polymers after traditional linear, crosslinked and branched types) [1]. Typically, dendrimers are used as well-defined scaffolding or nanocontainers to conjugate, complex or encapsulate therapeutic drugs or imaging moieties. As a delivery vector, the dendrimer conjugate linker or spacer chemistry plays a crucial part in determining optimum drug delivery to disease sites by conserving active drug efficacy while influencing appropriate release patterns. This review focuses on several crucial issues related to those dendrimer features, namely the role of dendrimers as nanoscaffolding and nanocontainers, crucial principles that might be invoked for improving dendrimer cytotoxicity properties, understanding dendrimer cellular transport mechanisms and the exciting role of dendrimers as high-contrast MRI imaging agents. The review concludes with a brief survey of translational efforts from research and development phases to clinical trials that are actively emerging.