Chemo-drug Controlled-release Strategies of Nanocarrier in the Development of Cancer Therapeutics.

Nanoparticles are widely used in cancer therapy because of their nanoscale, high surface ratio, multifunctionality and so on. With specific construction of nanoparticles, by choosing magnetic nanomaterials or citric acid-coated nanoparticle, scientists can kill tumor cells effectively and accurately, importantly reducing the side effects of conventional chemotherapy. Scientists not only have designed nanoparticles loaded with therapeutic drugs, but also those equipped with targeted molecules. These works have made nanoparticles multifunctional nanocarriers. As multifunctional nanocarriers, nanoparticles play an important role of drug delivery and normally, enabling drug delivery to tumor tissues is a difficult task. During the period of internal circulation, it is hard to maintain the stability of the nanocarriers not attached to normal cells or serum. With the application of stimulus-responsive nanomaterials, scientists have developed many nanocarriers with controllable drug release. These controllable drug delivery systems can quickly respond to microenvironmental changes (PH, enzyme, etc.) or external stimuli (photo, heat, magnetic or electric fields). Thus, to overcome the side effects of controllable drug delivery systems in vivo, in this article, we summarize the various kinds of stimulus-responsive nanocarriers for cancer therapy and discuss the possibilities and challenges in future application.