Nanomedicine system could enhance therapeutic drug effects
FROM RICE NEWS STAFF REPORTS
In an article featured on the cover of the March issue of Nature Nanotechnology, researchers from Rice, the University of Texas Health Science Center at Houston (UT-Houston) and the University of Texas M.D. Anderson Cancer Center present a proof-of-concept study for a new multistage delivery system for imaging and therapeutic applications.
This discovery could go a long way toward making injectable drugs more effective, said senior co-author Mauro Ferrari, adjunct professor in bioengineering at Rice and chair of the Department of Biomedical Engineering at UT-Houston.
“This is next-generation nanomedicine,” he said. “Now, we’re engineering sophisticated nanostructures to elude the body’s natural defenses, locate tumors and other diseased cells, and release a payload of therapeutics, contrasting agents or both over a controlled period. It’s the difference between riding a bicycle and a motorcycle.”
Getting intravenous drugs to their intended targets is no easy task. It’s estimated that only about one of every 100,000 molecules of a drug reaches its desired destination. Physicians are faced with the quandary of increasing the dosage, which can lead to side effects, or reducing the dosage, which can limit the therapeutic benefits. Ferrari said nanotechnology offers new and powerful tools to design and to engineer novel drug-delivery systems and to predict how they will work once inside the body.
“The field of therapeutic nanoparticles began with tiny drug-encapsulated fat bubbles called ‘liposomes,’ now commonly used in cancer clinics worldwide,” Ferrari said. “Targeting molecules were later added to liposomes and other nanovectors to assist in directing them to diseased cells.”
The multistage approach is needed to circumvent the body’s natural defenses or biobarriers, which act as obstacles to foreign objects injected in the bloodstream. To overcome this, Ferrari said, the team developed a multistage delivery system (MDS) comprising micron-size mesoporous particles that were loaded with one or more types of nanoparticles. The nanoparticles, in turn, could carry either active drug agents.
Co-author James Tour, the Chao Professor of Chemistry at Rice, said, “With this system, we have demonstrated the loading, controlled release and simultaneous in-vitro delivery of quantum-dots and carbon nanotubes to human vascular cells.”
In addition to circumventing biobarriers, the researchers are working on the modifications needed to efficiently deliver the MDS to a specific cancer.
“We have preliminary data that shows that we can localize a payload of diagnostic agents, therapeutic agents or a combination of both to target cells,” Ferrari said. “Once on site, the molecules can be released in a controlled way and then the MDS will degrade in 24 to 48 hours, be transformed into orthosilicic acid and leave no trace in the body.”
Ferrari heads both the multi-institutional Alliance for Nanohealth, an eight-member alliance that includes Rice, and UT-Houston’s NanoMedicine Research Center.
The study, titled “Mesoporous Silicon Particles as a Multistage Delivery System for Imaging and Therapeutic Applications,” was co-authored by Ashley Leonard and Katherine Price, both of Rice; Fredika Robertson of M.D. Anderson; and Ennio Tasciotti, Xuewu Liu, Rohan Bhavane, Ming-Cheng Cheng, Kevin Plant and Paolo Decuzzi, all of UT-Houston.
The research was supported by the Department of Defense, NASA, the Texas Emerging Technology Fund and the National Institutes of Health.