American Chemical Society AMA: I am Paul S. Weiss, professor of chemistry and much more at UCLA. Ask me anything about nanoscience and nanotechnology!



Hi Reddit, my name is Paul Weiss. I am Distinguished Professor of Chemistry & Biochemistry, of Materials Science & Engineering, and at the California NanoSystems Institute where I lead an interdisciplinary research group focused on understanding and controlling chemistry, physics, biology, and materials at the smallest scales.

I am also the founding, and current, Editor-in-Chief of ACS Nano one of the top scientific journals in nanoscience and nanotechnology.

I have to sign off now. Thank you Redditors for the great AMA discussion and questions! I will try to add a few links later, as noted below. /PSW

Are nanobots actually possible?

If yes, what do you think they'll be like? Clusters of enzymes that catalyse a particular series of reactions; or microscopic metallic insect-like creatures?


Our abilities to have molecules and assemblies move under control or responsively are very limited. (I work in this area - see ) On the other hand, there are proofs of principle in biology, viruses, biomolecular machines, etc. Our first successes in making molecular machines have been with hybrids, where we make (relatively small) modifications to biomolecules and assemblies or even modify viruses and parts of cells to function in some new or better way. One can (and Nature does) cluster enzymes and have them work in an assembly line. Here is an example from Nature (in ACS Nano): Here is a illustration of the synthesis and assembly of the proteins making up a biological nanoassembly: /PSW

Do you feel that the meaning and implications of "nanotechnology" have evolved over the years? In what ways? How do you feel about the evolution of the term?


Yes, the term is evolving, both for specialists and the public. I think it is critical to communicate to the public (and each other) what we are doing and what we are trying to do, rather than letting science fiction versions of nanoscience and nanotechnology determine that perception. Many of the other questions relate in some way to this issue and that is one reason I am happy to do this AMA! /PSW

  • Every science seems to have an idea of a turning point, or a hurdle to cross before things break loose. What is this hurdle for nanotech? E.g Quantum computing for CS, gene therapy for medical. Certain advancements that would change the science once harnessed.
  • What is the major focus for nano-chemistry? Batteries, conductive layers for circuilt boards, non-scratch coatings etc?

Turning point: I see a number of key milestones. One was realizing that the properties of nanomaterials are different than either molecules or bulk materials. To some extent, that realization came during the 19th century, but there was not so much we could do about it. That led to the second turning point: doing something about it. My view, is that came about once we could visualize the nanoscale world, with the invention of the scanning tunneling microscope (STM) in the early 1980's. While there were earlier techniques, the STM and its cousins, generalized the idea that we could "look around" at the nanoscale and it led both directly and indirectly to a revolution in our ability to make structures, too. More recently, there has been a revolution in our ability to make structures and to combine nanomaterials and that has led to the discovery of new properties. These have applications in many fields from devices to energy to medicine and more. (We will get back to those issues on other questions.)

There are many different focuses for nanoscience in chemistry. Batteries and energy storage are important with great upside potential. One surprise (to me and to us as editors at ACS Nano is that electrochemistry does not get the attention it deserves. See: /PSW

Hi Dr. Weiss, thank you for participating in this AMA.

The general public probably has a poor understanding of what nanotechnology actually entails. There have been countless books, tv shows, and movies that use the phrase as a sci-fi plot point without much explanation.

What are some examples of nanotechnology being put to use in everyday life? What would you consider to be the greatest piece of nanotechnology that current exists today?


I agree that views and perception of nanotechnology are strongly influenced by sci-fi etc. I help with some movies, TV shows, games, etc. through the Science Entertainment Exchange - - and otherwise, for that reason. (Here is an article on the last Terminator movie: ) I feel that it is incumbent upon those of us in Los Angeles, especially, to help in this regard. Also, it is great fun. Those in the entertainment industry are very similar to scientists. They are driven, have OCD, are intense, etc. Once one gets over the "You're so famous!" vs "You're so smart" thing, we are off to the races.

Nanotechnology is responsible for all our computers, smart devices, etc. as well as being the basis for paints (replacing the role lead once played), sunscreen, and so on. Increasing numbers of medical diagnostics (and eventually also therapies) will be based on nanotechnology - we will get to that below. /PSW

How has battery technology affected your research? Is there any significant drawbacks with the lack of battery progression over the years?


Drawbacks- absolutely! We have already glimpsed how we could do better if we had better battery technologies.

Until recently, I did not think that I personally had much to offer in this area. Then, one of my students, Andrew Serino, and a colleague in Materials Science & Engineering, Bruce Dunn, convinced me that the exquisite control that we have over surface functionalization could be of use, so we have put one toe in the water (and Andrew is probably working on a manuscript right now!). /PSW

US Senator Ron Wyden once said: "My own judgment is that the nanotechnology revolution has the potential to change America on a scale equal to, if not greater than, the computer revolution." Do you agree with this statement? What industry do you see nanotechnology having the greatest impact on in the near future?


I would argue that nanotechnology has been partly responsible for the computer revolution. ;-) Seriously, it is not a competition. Both fields are moving the world forward. We have already seen incredible impact on information technology.

One of the key aspects of nano is that it is also the scale of function in biology. We can use nanoscience and nanotechnology to understand biology and then hopefully turn it around and learn to interact more effectively with biological systems.

My colleague, collaborator, and wife, Anne Andrews (also AMA, and an editor at ACS Chemical Neuroscience) likes to say, "The brain has always been nano," because that is the synapse scale (10-20 nanometers) and thus the scale of function. I am glad of that happy coincidence, as it is how and why we first got together! For more on studying the brain, see: For nano and other tools for studying the microbiome, see: (and please admire the table of contents painting by Andrea Selby!) /PSW

As nanotechnology begins to enter the market for consumer use, will new disposal protocols become necessary to prevent nanoparticles from accumulating in unwanted places (rivers, lakes, etc.)? How have laboratories handled the safe disposal of such small objects?


I LOVE this question! Absolutely! It makes complete sense to think of product life cycles and recycling of materials. Materials can be made to dissolve or can be recaptured. We have a great effort in nano-environmental health and safety, and a focus in ACS Nano from the start. We have brought together experts from around the world to move the field forward (one example: - but also see papers and perspectives by our editor Andre Nel and others) and to address regulation, as well, and its relevance to safe commercialization. (see ) /PSW

What's the cleverest nano-scale tool you've created or seen?


I think that invention of the scanning tunneling microscope was the most important tool invented. Many further developments followed or were inspired by it. The inventors, Gerd Binnig, Christoph Gerber, and the late Heine Rohrer, did not expect to get atomic resolution, but it really changed the world. See my Conversation with Heine in our very first issue: /PSW

What areas of nanoscience are being unfairly neglected? Which one gets too much attention?


This question brings me back to an earlier one. Basic, fundamental electrochemistry is critical to so many energy harvesting and energy storage processes, it is shocking that it does not receive more attention and support. (Again, see: ) /PSW

Do you think the current publication system in science is damaging the scientific community?. How do you think it can be improved?


I think that some publishers have become (or started out) predatory in taking money to publish papers. I am a big fan of journals published by scientific societies and also push those societies to look out for the interests of scientists in their operations. There is a great deal more to discuss here, but I will say (and will follow up below) that we have done everything we can at ACS Nano to keep the interests of science and (next) scientists as our highest priorities. We have gone out of our way to be fair to our authors (, readers, and referees) and to look for research and research groups that we have not previously known (it is part of our review of each issue that we publish). We operate differently than other journals, but hopefully what we are doing will start to rub off on others as we get increasing support from the scientific community. /PSW

Hi Paul, Big fan.

In your opinion, do electrons traverse a single molecule through space, or through bonds, or both?


Thanks so much! Electrons traverse through all of the above. This is something we know from early STM images and their interpretation. /PSW

Do you think that using nanotechnology for cancer treatments is a realistic endeavor? What would be some problems associated with this?


The goal is to combine targeting, responsive delivery, and reporting all into one nanomaterial. On the other had, I like to say that another definition of a nanomaterial is something that gets cleared by the liver, kidneys, or spleen. So, if you are targeting those organs, you are in luck.

In fact, there is much we do not understand about cancer biology. There are linked biochemical pathways that need to be addressed simultaneously. Approaching cancers in this way may be more productive than thinking of organs. Nano and other approaches can be helpful in combined therapies in this regard.

Some of the problems include getting through regulatory requirements with materials that are not perfectly defined. Marc Davis at Caltech had an interesting article in PNAS describing this process where he tried to use the simplest possible design in order to make it through the regulatory process (it is not jumping out at me, but I will try to post a link later).

I do think that there is promise for cancer, but there are also many other diseases that deserve attention and might be more straightforwardly addressed via nanotherapies. /PSW

Hi Dr Weiss, thanks for doing this. I've spoken with some of your grad students before, and one of their projects that seemed quite fascinating was the development of a physical, nanoscale neutral network. I wasn't able to find any relevant publications on your website to read more, but do you think you could explain how that works? How is memory stored and the network "trained" in this situation?


We have not yet published this work (nor gotten it to work yet), but stay tuned! /PSW

1) Has the way you refer to nanotechnology changed as the term has gained traction in the public imagination. Has the word become a bit of a dirty term like "cold fusion" did?

2) Do you think our current legislation/safety standards reflects the actual hazards of nanomaterials compared to traditional chemical forms e.g. ability to penetrate cell wall etc.


1) I think the public imagination re nano is up for grabs at the moment. That is one reason that it is so important to let people know what we are doing and why (and thereby, what nano is).

2) Nanomaterials cannot be treated as conventional chemicals in terms of safety, simply because there are too many of them (i.e., there are not enough animals and not enough money on the planet to do conventional testing). I think (and we have published a number of articles of various sorts on this idea) that hierarchical strategies can identify broad classes of materials that are safe to commercialize vs those that require further attention both in terms of materials characterization and safety issues. See: /PSW

Will the rise of quantum computing have a big impact on nanotechnology in the future? And if so, how?


There is a good possibility of a significant role for nanotechnology in the development of quantum computing. If quantum computing became available (and I pay loose attention to the topic), then our capabilities of calculating structures, properties, and function of nanomaterials may be enhanced. How much, we do not know as the first algorithms are just being developed now. See the work of Alán Aspuru-Guzik at Harvard, for example: /PSW

Hello Dr. Weiss, Do you think nanotechnology when associated with biomolecules, i.e. macromolecules like proteins, lipids and polysaccharides be considered in the same light as inorganic nanotechnology?

Do you think that the scientific community should distinguish the nanometric parameters when it comes to nanochemistry of biomolecules.


Progress in both areas is moving rapidly. As I mentioned above, the scale of function in biology is the nanoscale, so there are unique opportunities to interact with biological systems. Inorganic nanomaterials also interact with biological systems. Some of the same tools and methods of characterization apply. Sometimes, we learn from one side or the other and translate advances back and forth. The bottom line for me is that I do not see any great divide. /PSW

How far are we from actual programmable matter on the atomic/molecular level , or matter-assemblers? Are there theoretical avenues towards configuring and assembling materials "on the fly"?


Once upon a time, I was the first one to move atoms around on a surface (when I was a postdoc at IBM in 1989, but I did not spell anything). I just wanted to see what was underneath, so I moved clusters of atoms (and individual molecules) with the scanning tunneling microscope.

I do not see an "assembler" as terribly useful in that molecules and materials follow the rules of chemistry. Thus, one cannot create arbitrary materials that do not follow those rules.

On the other hand, there are biological examples of converting codes (DNA/RNA) to proteins and then further conversions with enzymes (about 100 different reactions are known) to greater chemical diversity. That is how we go from ~21,000 genes in humans to ~1,000,000 proteins (that also includes mix and match in the coding). We can imagine co-opting the strategies of or modifying biological molecular machines to make more diverse materials and a number of groups work on that (e.g. Peter Schultz at Scripps - his website is rather out of date, so it might be better to do a search of papers/talks/etc.).

We have also found programmability in self- and directed assembly (our group and others), programmed linkers (here is a paper from Chad Mirkin that came out today: ), and other strategies. These do not involve machines and assemblers, but rather designed interactions, selective exposure, and controlled conditions. In a way, this is also how biology works. /PSW

As ACS Nano is approaching its 10 year anniversary, what has it been like working with the journal since it's inception? Specifically, what was it like getting it started, what have been some of your favorite successes, and is there anything you would like to see change looking to the future?


It has been incredibly exciting to work on ACS Nano from even before the start. We had a fantasy about how it would work and how we would progress when we started. To our surprise, it happened!

We decided we wanted to help guide, advance, and accelerate progress in the field by bringing ideas together from many different fields. We wanted rigor in what we published in that others would be able to follow the research described in papers (we felt the field was plagued by the publication of communications that lacked important details and in many cases later turned out to be wrong, in part because the key missing pieces in the research had not been done). We were able to get support of key authors and advisors around the world who felt the same way.

We also set it up to be intellectually stimulating for us as editors. Who would not want to talk to Dawn Bonnell, Paula Hammond, Grant Willson (our original three associate editors) every day? I always do! So, we set the journal up to be a collaboration between editor/scientists, rather than farming out manuscripts and forgetting about them. Now, we have expanded greatly in terms of editors - (with more in the coming year). We have kept the strong collaboration going and choose editors who are thoughtful, critical, broad, fair, and social. That is part of the reason that you often see us together at meetings. It is also why we put together so many thought pieces on what the challenges and opportunities lie ahead for the field (here is a recent example - ). I mentioned the technology roadmaps for the BRAIN and National Microbiome Initiatives above. More are to come.

It is also why we do everything we can to treat our authors fairly - we are author/scientists, too. Every manuscript is seen by at least two of us and any editor can champion a paper and only scientists make decisions. We are very tough on each other. We are also always looking for who in the world has something exciting to report or to say. We are all also extremely active and are always circling the globe for our science (we try to announce talks editors are giving on Twitter @acsnano, if you would like to find us in person).

It has continued to be a great joy all around.

Our goal is to become the public face of nanoscience and nanotechnology, so that when non-scientists read about work that we have published in whatever newspaper or magazine in the world or hear about it online, on TV, or on radio, when they hear "published in ACS Nano" they know what that means. We are on our way, in that we (intentionally) get a great deal of public attention for what we publish, and we work hard to establish those contacts for our authors and for our field.

Hang in there as I think you will see much more to come. /PSW

Hello thank you for doing this AMA! As someone very interested in nanoengineering, and wanting to pursue it as a career, what would you suggest is the best place to start in terms of an educational background?


I would choose a basic area of engineering (or science) and focus on the core curriculum. While doing that, get in a research group early, ideally one with interdisciplinary work (and people with a diverse range of backgrounds). Also, while taking your classes, look for interesting seminars and visitors across all relevant fields of nanoscience and nanotechnology - get on the listserves for the series and if you have a nanocenter, keep track of what they are doing there in terms of seminars, conferences, etc.

Good luck and I look forward to meeting you in the nano world and ours! /PSW

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