Friday, December 10, 2010

Nanobots: Truth is “Cooler” than Fiction

I am often proven wrong (just ask my wife), but usually not so quickly.  This time it took only 4 days.

On Tuesday, at the request of the NRC Education and Outreach Office’s Joyce Palmer, I spoke to a group of students who make up the Rockin' Robots, a FIRST LEGO League team from Faith Lutheran School in Marietta.  In particular, these elementary students are tasked, through the 2010 Body Forward Challenge, with exploring “the cutting-edge world of Biomedical Engineering to discover innovative ways to repair injuries, overcome genetic predispositions, and maximize the body's potential, with the intended purpose of leading happier and healthier lives.”  Joyce wanted to know if I could address some of their questions related to bionanotechnology and provide a dose of reality.  I prepared myself to dash water on their images of nanorobots coursing through the bloodstream fixing problems and keeping us fit and healthy.  I remember thinking the movie Fantastic Voyage (based on the Isaac Asimov novel) was really cool at their age (and it had Raquel Welch in it).

I listened carefully, and with growing amazement, as the student leader of the team described their plan to use synthetic sandcastle worm glue to improve the healing of broken bones in the body.  This concept is based on the research of Russell Stewart (University of Utah).  He went on to explain that they would target the site of the breakage by coupling the delivery system with antibodies to osteoprotegerin, which is produced in the body to stimulate bone growth and increase bone density.  Finally, a liposome delivery system was chosen for the project.  My preconceived notions took another hit when I read on the team’s website (Osteo Repairo, a play on a Hogwarts spell) that they “first thought we would use nanobots to get there because they are cool and really small but then we kicked things around …and asked what could bond with the antibodies and he [Team Coach Dr. Shawn Jobe] explained about liposomes. Some of us have never heard of liposomes. Zach really thought they were awesome and Ethan built a model of one.  After that we were all in with liposomes as a delivery method.”

Clearly, these students did not require me to lecture them on the difference between the promises of nanotechnology and the hype that is often used in both fiction and marketing.  They were well-grounded in the facts and only needed me to clarify some of the subtleties (although I confessed to them that I am not an expert in the specific areas of their research).  We discussed options for getting the treatment into the bloodstream (including microneedle patches), and I cautioned them that antibodies can have non-specific binding that could lead to unwanted delivery consequences.

Finally, my crow-eating was complete when I read this morning about a new drug delivery concept from the Laboratory for Nanobioelectronics at UC San Diego that involves “the directed delivery of common polymeric and liposomal drug carriers using catalytic nanomotors.”  In particular, the futuristic image of an autonomous nanomachine, the specific image I tried to minimize in my discussion with the students, is now one step closer to reality.  As lead researcher Joseph Wang puts it: “We are all motivated towards realizing the vision of the 1966 movie Fantastic Voyage vision and by the potential to enhance medical treatment.”

I guess the Rockin’ Robots are not the only ones who think nanobots are “cool and really small.”

Friday, December 3, 2010

It's All Chemistry

I attended the Georgia Tech School of Mechanical Engineering's Gegenheimer Lecture on Innovation yesterday.  While the speaker, GT alumna Prof. Robin Murphy (Texas A&M), presented an interesting discussion on the use of robots in search and rescue, with considerable attention paid to the interaction between humans and robots, it was the student’s question I happened to hear on my way out that really attracted my attention. This student wanted to know, in the spirit of innovation, if there was something the speaker believed but that others may not.

I found this a thought-provoking inquiry, and spent the next several moments during my walk back to my office considering my own beliefs (scientifically speaking) and how they mesh within the larger scholarly community.  In particular, I thought back about 10 years, during the early days of the current nanotechnology revolution and of my impression at that time, with a soupcon of righteous indignation as a card-carrying chemist, that this “new” technology is nothing more than chemistry with a fancy new name.  While I have since softened this stance as I gain more knowledge of the breadth of this enterprise, fundamentally I still believe that chemistry contains the elemental principles behind most of nanoscience and nanoengineering.  Particles, materials, surfaces, and even devices are all manifestations of inter-atomic and inter-molecular forces (the domain of chemistry) that take on added importance when the materials themselves are on the same scale as their constituent components.  The reason a gecko can walk on the ceiling is because the combined van der Waals forces between the millions of nano-sized spatulae on its feet and the ceiling surface are greater than the opposing force of gravity.  This is the take-home message I drill into students: There is nothing scientifically new that occurs on the nano-scale, but rather the same interactions and forces we have known about since the advent of organized science take on added magnitude compared to the macro-scale forces.

The centrality of chemistry in our everyday lives was even used by my American Chemical Society colleague Don Hicks when he created a viral marketing campaign (see the bumper magnet below) a few years ago to spur public recognition of the value of our science.

All of this makes the news article I read earlier this week even more grating.  It seems a research team from the University of Missouri has developed a new process for gold nanoparticle synthesis that avoids the toxic reagents normally used in such reactions.  Instead, the researchers discovered that phytochemicals found in cinnamon (yes, that spice that is omnipresent in our kitchens this time of year) can act as effective reducing agents for turning gold salts into gold nanoparticles.  This green process is wonderful and I applaud their ingenuity.  However I was taken aback by this assessment:  "The procedure we have developed is non-toxic," Kannan said. "No chemicals are used in the generation of gold nanoparticles, except gold salts. It is a true 'green' process." 

This reminded me of the challenge by the Royal Society of Chemistry a few years ago for anyone to produce a material that is “chemical-free.”  Needless to say, no one has claimed the prize.