Month: May 2005

As some Sciencebase visitors will know, I was on the editorial team that published Sir Harry Kroto’s original paper on fullerenes many moons ago. Now, I see there’s something of a reason not to be cheerful regarding this discovery, at least according to research published by the ACS.

In a challenge to conventional wisdom, scientists have found that buckyballs dissolve in water and could have a negative impact on soil bacteria. The findings raise new questions about how the nanoparticles might behave in the environment and how they should be regulated, according to a report scheduled to appear in the June 1 issue of Environmental Science & Technology.

Recent studies showed that even low concentrations of fullerenes could affect biological systems such as human skin cells, but this latest study is among the earliest to assess how buckyballs might behave when they come in contact with water in nature.

Fullerenes have until been thought of as insoluble in water, which suggests they pose no imminent threat to most natural systems. “We haven’t really thought of water as a vector for the movement of these types of materials,” says Joseph Hughes of Georgia Tech and lead author of the study.

But, Hughes and his collaborators at Rice University in Texas have found that buckyballs combine into unusual nano-sized clumps – which they refer to as “nano-C60” – that are about 10 orders of magnitude more soluble in water than the individual carbon molecules.

In this new experiment, they exposed nano-C60 to two types of common soil bacteria and found that the particles inhibited both the growth and respiration of the bacteria at very low concentrations – as little as 0.5 parts per million. “What we have found is that these C60 aggregates are pretty good antibacterial materials,” Hughes says. “It may be possible to harness that for tremendously good applications, but it could also have impacts on ecosystem health.”

It will be interesting to see how the media takes to these findings, especially given that buckyballs are nanoscale objects. No doubt it will be just one more objection from the chemophobes to the development of new chemical technologies.

UW-Madison’s Biology New Media Center has added a new tool to its gleaming fleet of technology dedicated to making biological concepts come to life. The Z-Corp Three-Dimensional Printer, purchased for $57,000 can create customized and remarkably lifelike 3-D replicas of virtually anything under the sun.

Ted Pan, a technology specialist in the center, exhibited a table full of early experiments with the printer, including double helices, complex proteins, bacteria flagella, animal skulls and – for kicks – a toy sports car. One particularly menacing looking mass of horn-shaped proteins was a replication of the anthrax bacterium. Another model was of a new protein discovered by a UW-Madison scientist, who is bringing handy “copies” of the structure with him to conferences.

The 3D scanner looks very much like a printer, except with a curved glass top that covers the ink-jets and a deep tray of white polymer powder. The jets move back and forth over the tray, creating the object one layer at a time based on a three-dimensional computer image. Most of the larger objects are made hollow to reduce material costs.

The objects come out of the printer fairly brittle, but are then fortified with glues that make them remarkably strong. The printer can make things up to 10 inches tall and literally create moving parts, such as a spool encased with ball bearings.

Pan says that educators are excited about the academic uses of the new device. Even with the level of 3D sophistication in computing, sometimes there is no substitute for picking something up and looking it over.

“The technology has been around for some time and has been widely used by architects and engineers,” Pan says. “What’s newer are the applications as a teaching tool. This is especially useful when teaching about complicated structures like molecules or viruses, where having something in hand makes it easier to conceptualize.”

Pan’s goal is to make the new technology available for broader campus use beginning this fall. He is describing the possibilities of the new tool at the annual Teaching and Learning Symposium in May, which showcases classroom innovation.

Located in the Biotechnology Center, the Biology New Media Center is devoted to enhancing the visual potential of discovery, with video editing suites, large-scale printing, online materials and 3D computer monitors. It can also translate the real into the virtual with a scanning device that makes three-dimensional computer programs out of real objects. The center is widely used not only for instruction, but also for scientific presentations where visual enhancements are crucial.

There is an old WebMD item about why your urine smells funny after eating asparagus. I only bring it up because the stalky delicacy is once again in season; delicious they are too from our local farm shop. Anyway, the WebMD item mentions that it’s the presence of a sulfur compound known as mercaptan in the asparagus (also found in rotten eggs, garlic, onions and skunk scent) that leads to the smell.

The article says, and I quote: “When your digestive tract breaks down this substance, by-products are released that cause the funny scent. The process is so quick that your urine can develop the distinctive smell within 15 to 30 minutes of eating asparagus.”

I’m not sure they’ve got that entirely straight though, it is definitely a sulfur compound being metabolised that releases the methanethiol giving urine the smell, and most researchers would suggest the amino acid methionine is the source. If it weren’t we’d also talk about asparagus poo as well as pee as the breakdown product would be present in both.