This toxin-independent treatment would allow doctors and hospitals to carry out one general treatment rather than multiple toxin-specific treatments.
“This is a new way to remove toxins from the bloodstream,” Liangfang Zhang, a nanoengineering professor at the UCSD Jacobs School of Engineering, said in a press release on April 14. “Instead of creating specific treatments for individual toxins, we are developing a platform that can neutralize toxins caused by a wide range of pathogens.”
In a lab study conducted on mice with MRSA (methicillin-resistant Staphylococcus aureus), a strain of antibiotic resistant bacterium, 89 percent of the mice pre-injected with “nanosponges” survived lethal doses while those post-injectionedinjected resulted in a 44 percent survival rate. MRSA is responsible for many infections in humans that are difficult to treat.
The “nanosponges” are wrapped in red blood cell membranes to avoid being attacked by the immune system. Liangfang Zhang and his lab at UCSD created this red blood cell cloaking technology by expanding on their previous research that demonstrated that nanoparticles disguised as red blood cells could safely travel in the bloodstream.
The team used a centrifuge to separate red blood cells from a blood sample. The cells were then placed in a solution causing them to swell and burst, releasing hemoglobin and leaving the skin behind which is then mixed with the ball-shaped nanoparticles.
A “nanosponge” has a diameter of approximately 85 nano-meters — 3000 times smaller than a red blood cell, allowing thousands of “nanosponges” to be created from one red blood cell membrane.
Using the cloaking technology, “nanosponges” protect red blood cells by diverting harmful agents from the vital cells and absorbing the toxins. The liver incurred no noticeable damages after metabolizing both the “nanosponges” and collected toxins.
Test-tube experiments demonstrated that the number of toxins each “nanosponge” could absorb was dependent on the toxin. Numbers ranged from 85 monomers for alpha-haemolysin toxin produced by MRSA to 850 monomers of melittin, the active component of bee venom.
The researchers are now working to apply their work to create approved therapies. Researcher “Jack” Che-Ming Hu said one of the first applications would be an anti-virulence treatment for MRSA. Hu earned his Ph.D. in bioengineering from UCSD in 2011. The team says that the next step is to conduct clinical trials.
Zhang and his team of engineers at the Jacobs School of Engineering published their findings in Nature Nanotechnology on April 14 and will present part of their work on April 18 at Research Expo, the annual graduate student research and networking event for the engineering department.