RESUMO
The reshaping of the world's aging population has created an urgent need for therapies for chronic diseases. Regenerative medicine offers a ray of hope, and its complex solutions include material, cellular, or tissue systems. We review basics of regenerative medicine/stem cells and describe how the field of molecular imaging, which is based on quantitative, noninvasive, imaging of biological events in living subjects, can be applied to regenerative medicine in order to interrogate tissues in innovative, informative, and personalized ways. We consider aspects of regenerative medicine for which molecular imaging will benefit. Next, genetic and nanoparticle-based cell imaging strategies are discussed in detail, with modalities like magnetic resonance imaging, optical imaging (near infra-red, bioluminescence), raman microscopy, and photoacoustic microscopy), ultrasound, computed tomography, single-photon computed tomography, and positron emission tomography. We conclude with a discussion of "next generation" molecular imaging strategies, including imaging host tissues prior to cell/tissue transplantation.
RESUMO
Recently, co-delivery of siRNA and anticancer drugs has drawn much attention in the treatment of drug-resistant cancers. Drug resistance is exhibited by cancer cells, which limits the efficacy of chemotherapy. When siRNA and anticancer drugs are delivered into cancer cells simultaneously, the siRNA is expected to silence the genes related to drug resistance, decreasing the drug efflux pumps and activating the cell's apoptosis pathways. In a timeframe following the release of siRNA, the accumulation of the co-delivered anti-cancer drug inside of the cancer cells will increase, resulting in promoted chemotherapeutic effects. Several classes of nanocarriers have been designed based on polymers for co-delivery, including surface-modified polymer nanoparticles (NPs), polymer micelles, dendrimers, polymer nanocapsules, polymer-modified liposomes, and polymer-modified silica and gold NPs. Compared with separate delivery, co-delivery showed significant advantages in the treatment of drug-resistant cancers. This review focuses on polymers in the co-delivery of siRNA and anticancer drugs, and summarizes key advances in the recent several years.