The design and application of functionalized mesoporous silica nanocarrier

With the rapid development of nanotechnology, nanomaterials with unique physical and chemical characteristics, have offered tremendous potential for biomedical application. Among them, mesoporous silica nanoparticles (MSNs), a class of well-established nanoplatforms with different structures and compositions, have been widely used to develop drug delivery systems owing to their unique physical-chemical properties, such as tunable particle/pore size, high surface area and pore volume, easy surface modification, remarkable stability and biocompatibility, and high drug loading efficiency. Moreover, MSN-based nanocarriers with “zero premature release” property have proven to be excellent devices for drug delivery. A variety of fluorescent dyes and pharmaceutical drugs were encapsulated in MSNs for controlled release. In addition, numerous efforts have been made to develop smart nanovalves on the surface of MSN to provide on-command release of drug in response to different stimuli, including light, enzymes, pH, redox, temperature, and competitive molecules. Furthermore, the outer surface of MSN can be modified with various functional groups, that play critical roles (stealth or targeting) in overcoming the multistage barriers found in the drug delivery process. Fabrication of MSN-based, multifunctional, stimuli-responsive drug delivery systems can effectively encapsulate anticancer drugs and can maintain “zero premature release” before reaching the diseased site. Once they arrive at the tumor site with the aid of targeting groups, the nanodevice can be activated by a specific stimulus to release the drug. The delivery of anticancer drugs to a specific target site can alleviate toxic side effects and improve the therapeutic index of drugs; thus, achieving significantly enhanced anticancer efficiency. Herein, we reviewed various strategies for the design of stimuli-responsive, MSN-based drug delivery systems, and multifunctional MSN for targeted cancer therapy.