RESUMEN
In the past few decades, microbubbles were widely used as ultrasound contrast agents in the field of tumor imaging. With the development of research, ultrasound targeted microbubble destruction technology combined with drug-loaded microbubbles can achieve precise drug release and play a therapeutic role. As a micron-scale carrier, microbubbles are difficult to penetrate the endothelial cell space of tumors, and nano-scale drug delivery system—nanobubbles came into being. The structure of the two is similar, but the difference in size highlights the unique advantages of nanobubbles in drug delivery. Based on the classification principle of shell materials, this review summarized micro/nanobubbles used for ultrasound diagnosis or treatment and discussed the possible development directions, providing references for the subsequent development.
RESUMEN
Malignant tumor is a major disease affecting human health. The nano-delivery system itself has a unique size effect and it can achieve tumor-targeted distribution of drug molecules, improve the therapeutic effect, and reduce the toxic and side effects on normal tissues and cells after functional modification. Patient-derived xenografts (PDX) models can be established by transplanting patient-derived cancer cells or small tumor tissue into immunodeficient mice directly. Compared with the tumor cell line model, this model can preserve the key features of the primary tumor such as histomorphology, heterogeneity, and genetic abnormalities, and keep them stable between generations. PDX models are widely used in drug evaluation, target discovery and biomarker development, especially providing a reliable research platform for the diagnosis and treatment evaluation of nano-delivery systems. This review summarizes the application of several common cancer PDX models in the evaluation of nano-delivery systems, in order to provide references for researchers to perform related research.
RESUMEN
In the research on cancer theranostics, most environment-sensitive drug delivery systems can only achieve unidirectional and irreversible responsive changes under pathological conditions, thereby improving the targeting effect and drug release performance of the delivery system. However, such irreversible changes pose potential safety hazards when the dynamically distributed delivery system returns to the blood circulation or transports to the normal physiological environment. Intelligent reversible drug delivery systems can respond to normal physiological and pathological microenvironments to achieve bidirectional and reversible structural changes. This feature will help to precisely control the drug release of the delivery system, prolong the blood circulation time, improve the targeting efficiency, and avoid the potential safety hazards of the irreversible drug delivery system. In this review, we describe the research progress of intelligent reversible drug delivery system from two main aspects: controlled drug release and prolonged blood circulation time/enhanced cellular internalization of drug.
RESUMEN
Cell-penetrating peptides are composed of positively-charged amino acids that can mediate molecules or nano-carriers across cell membranes. However, most of the known cell-penetrating peptides have no cell-or tissue-specificity, with affinity to almost all types of cells in internalization. The non-specificity of cell-penetrating peptides is a significant obstacle in the application to targeted delivery of imaging probes and therapeutic agents. Accordingly, many studies focused on selective switching of systemically-delivered inert cell-penetrating peptides into active forms in diseased tissues. Tsien groups introduced the concept of activatable cell-penetrating peptides in 2004. Subsequently, a growing number of similar delivery systems (molecular or nano-sized) have been documented, and the sensitive factors have included enzyme, lower pH, light and exogenous component. In this paper, we make an overview of the development of activatable delivery system in recent years.