More Nanoparticle Bondage

In a previous entry, I mentioned a technique whereby gold nanoparticles could be attached to the exterior of fungal cells to form unusual hybrid materials. Once the gold scaffolding was complete, the fungi could be removed (digested), leaving behind 3 dimensional gold structures. This started me thinking that there might be a rich field of exploration here, finding simple ways of attaching metal nanoparticles like gold to new substrates in the hopes of creating new 3-dimensional structures with unusual properties. Even better, many of these techniques would be based on aqueous chemistry, which make them especially appealing (to me at least).

Of course, within a week or two of that article, two more articles appeared which demonstrated that other research groups are already way ahead of me in this area.

In the first paper, J. P. Hinestroza and coauthors at Cornell University (Ithaca, NY) and the University of California, Davis, described a method of applying silver nanoparticles to porous nylon fibers, resulting in fibers with strong antibacterial properties. By using AQUEOUS chemistry techniques (pH control, isoelectric points, citrate stabilization, etc.), they found they could control the resulting properties of the final material. When you consider the fact that the original gold and silver nanoparticles can be easily produced by reducing aqueous solutions of the metal salts, you begin to realize just how much fun this type of project could be for an aqueous inorganic chemist like myself.

In the second paper, Y. Yin and co-workers at the University of California, Riverside, described the synthesis of gold nanoparticle catalysts supported on silica-encapsulated Fe3O4 spheres and protected by a porous silica shell. The purpose of the silica shell was to fix the gold nanoparticles in place for catalysis. Apparently the resulting material were found to be a good catalyst for the liquid-phase reduction of 4-nitrophenol with NaBH4. Interestingly, the purpose of placing the catalyst onto Fe3O4 cores was to give the researchers a convenient way of separating the catalyst from the reaction mixture. Nice.

I'm predicting a whole slew of papers are going to start appearing which involve placing gold and silver nanoparticles on every material imaginable.

Of course, maybe that's already happened and I just haven't noticed yet.

Ah yes..., it feels good to be blogging again.

Merry Christmas

I naively thought all the extra time I would have available to me during my career transition would translate into my having more time to devote to this blog. I actually do have extra time, despite all the inevitable timesinks (job search, buying presents, rearranging my office at home, etc.). However, I've also discovered that it's a lot harder for me to update this blog if I am not following a regular schedule throughout the day. So I ask you to bear with me as I begin to develop a regular routine.

I hope everyone has a very merry Christmas today.

Update

Well that didn't take long. I am officially a patient now. Damn viruses.

Another Use for Copper

I've just returned from a 5 day visit with my parents in Missouri (which partly explains my recent lack of postings). It was great to visit, but it's always good to come back home again. Unfortunately, "home" is 20 degrees colder, my wife's computer had stopped working, and everyone in the house has some sort of vicious stomach virus. I briefly considered going to a motel, but my wife would have killed me.

Really.

So I spent Monday passing out medicines, cleaning up various messes, mostly eating by myself, and fixing the computer. The computer's working now, which is more than I can say for the rest of the family. I've already resigned myself to the inevitability of becoming a patient myself within the next couple of days. Perhaps I should invest in some copper bedsheets.

Why copper, you ask?

I have previously discussed the anti-bacterial properties of silver and gold. The list of purchasable items containing silver grows daily, and includes bandages, socks, towels, bedsheets, ointments, plastic food containers, soaps, and washing machines. Gold is not at that level of marketability yet, with gold-laced soap being the main use of its anti-bacterial properties. So it only makes sense that copper, the third element in the 1B group, also exhibits some of these same properties. In fact, in Chili, the biggest suppler of copper, copper fibers are being added to socks, towels, pillow cases and underwear. Copper sponge filters are being tested for their ability to purify water. I suspect it won't be long before this becomes a new marketing opportunity.

Despite their anti-fungal properties, these elements may also be used in conjunction with fungi. In a novel approach, fungi are being used as templates for stabilizing gold nanoparticles. Under the right conditions, fungi can absorb microscopic metal particles onto their surfaces, creating unusual clusters of nanoparticles, and resulting in metal-fungus hybrids which are able to catalyze certain reactions. It's certainly a novel way of doing bioinorganic chemistry.

Gotta go. I hear some rather vile noises emanating from my son's bedroom.