'Smart' nanoparticles as drug delivery systems for applications in tumor therapy

Introduction: In the therapy of clinical diseases such as cancer, it is important to deliver drugs directly to tumor sites in order to maximize local drug concentration and reduce side effects. This objective may be realized by using smart' nanoparticles (NPs) as drug delivery systems, because they enable dramatic conformational changes in response to specific physical/chemical stimuli from the diseased cells for targeted and controlled drug release.Areas covered: In this review, we first briefly summarize the characteristics of smart' NPs as drug delivery systems in medical therapy, and then discuss their targeting transport, transmembrane and endosomal escape behaviors. Lastly, we focus on the applications of smart' NPs as drug delivery systems for tumor therapy.Expert opinion: Biodegradable smart' NPs have the potential to achieve maximum efficacy and drug availability at the desired sites, and reduce the harmful side effects for healthy tissues in tumor therapy. It is necessary to select appropriate NPs and modify their characteristics according to treatment strategies of tumor therapy.