Nanotechnology from Nature: Improvements in Ultrasound

Gas vesicles—incredibly tiny organelles found in photosynthetic microorganisms such as bacteria and archaea—can be used for improvements in ultrasound imaging. This seemingly bizarre idea came to engineer Mikhail Shapiro as he was reading an article.

Ultrasound functions by emitting sound waves into people’s tissue and organs. When these waves encounter a structure that has a different density (such as bone), some of the sound waves bounce back and return. If this process is timed, it is possible to establish the depth of the tissue or organ inside the organism, If one times how long this takes, it is possible to establish how deep the tissue or organ is, creating an image of the inside of the body.

This all works well, but there are difficulties if one wants to image something that is not strictly considered major anatomy—for instance, the bloodstream. In the bloodstream, structures known as microbubbles scatter sound waves in a way that allows the flow of blood in the bloodstream to be imaged. However the rather large size of microbubbles does not permit them to be used outside of the bloodstream. One might think the obvious solution to this problem would be to create even smaller microbubbles; however, due to the nature of microbubbles they cannot be made much smaller than they already are.

Taking a completely different approach would allow for a solution: gas vesicles—incredibly small nanostructures—can be used instead of microbubbles in order to image cells. Of course, there are several difficulties and obstacles with this solution as well, but Shapiro and his group have been working on solving these issues. To read more about how gas vesicles may be used in this way, please read this article.

This is an image of gas vesicles. Credit: Mikhail Shapiro/Caltech

Shapiro and others who worked on this project (Patrick Goodwill, Arkosnato Neogy, David Schaffer, and Steven Conolly of UC Berkeley, and Melissa Yin and F. Stuart Foster) have published a paper online in Nature Nanotechnology tiled “Biogenic gas nanostructures as ultrasonic molecular reporters”.

This discovery is very useful in the medical world, as the new ultrasound can help people track and view the growth of many different cell types (such as neurons and tumor cells) using ultrasound. Ultrasound is a very useful medical tool: it is noninvasive, carries few risks, is very easy to use (as it is portable), and is an effective diagnostic method in medicine. Improvements in this technology will lead to the earlier tracking of diseases and, consequently, to improved health in many different fields of medicine such as cardiology, obstetrics, gynecology, musculoskeletal health, and oncology. Detection of a health problem is the first step towards recovery, and often times treatment is given too late. With improved ultrasound techniques, people may benefit from a quicker diagnosis and longer lives.

This discovery is indeed incredible. The fact that it has been inspired by something found in nature—gas vesicles—makes it even more so.  Mikhail Shapiro put it rather well when he said “People have struggled to make synthetic nanoscale imaging agents for ultrasound for many years…To me, it’s quite amazing that we can borrow something that nature has evolved for a completely different purpose and use it for in vivo ultrasound imaging. It shows just how much nature has to offer us as engineers.” Using nature as an inspiration can (and has) lead to many breakthroughs in the medical world. Scientists and engineers alike should use the wonderful resource available to them—and to everyone—in order to make and invent new technologies. These scientists and their research should be supported, as it can be incredibly beneficial to human health and quality of life.

Do you also find that nature has been a useful tool in scientific and technical advances? Do you support scientific research? Please share any thoughts you may have on this discovery (or related discoveries) below.

Faster Internet? Caltech’s New Laser May be the Answer!

I’m sure some of you may have already heard that a new laser developed at Caltech could lead to a faster internet. This information was released over a month ago, and the team performing research has been working on the project for five years.

Credit: Amnon Yariv/Caltech

The optical-fiber network used today still employs the distributed-feedback semiconductor (S-DFB) laser—a laser that was developed over 40 years ago by the same researcher who has been working on the new laser mentioned in this post—to transmit information. Some major modifications in the way the S-DFB laser functions have been made by a team at Caltech in order to create a newer laser with greater ability to transmit information.

To read more about how this laser was developed, please visit the article at Caltech. In order to view the official research paper “High-coherence semiconductor lasers based on integral high-Q resonators in hybrid Si/III-V platforms” on this subject, please visit this link at Caltech or the PNAS paper. A relatively shortened version of the article can also be viewed here.

I find the development of this new laser incredibly promising and sincerely hope that the benefits this laser brings will be worthwhile. In today’s world, astronomical numbers of people use the internet for a wide array of purposes. This makes internet speed a substantial factor in the development of our society.

Please share your thoughts on internet use and speed in the comments section below. Had you heard of this laser prior to reading my post? Do you think the creation of this laser is an important step forward? Feel free to share any opinions you may have regarding this topic.

On a similar note regarding the age of widespread internet use, I would like to briefly discuss internet privacy. I’ve inserted the link to the student blogging challenge post concerning this issue here. Several videos are provided on the site.

In the past few months, I have heard a lot of misconceptions about internet privacy and I would like to clear some things up. Very large amounts of information about every internet user (or nonuser) can be found on the internet. This information ranges from private data posted on secure sites by hospitals concerning the health of individuals, to Google searches (Google records the IP address of every computer that uses the search engine, as well as the account used should the user have a Google account), texts and emails, online purchases (ex Amazon), credit card information (such as items purchased and amount spent), private user information on sites users registered with, posts and comments on social media sites and blogs (Twitter, Facebook, Instagram, and even this blog would be included) and even geographic location (for those who have GPS technology installed in their smartphone(s)).

This may come as a slight shock to the uninformed individual; however, it is important for one to differentiate between the varying degrees of accessibility of the information recorded in these instances. When internet users register for an account on a site, the information they provide the site with can be easily obtained in some cases. Depending on the security of the site, privacy settings, and the Terms of Agreement for the site, this information can be open freely to all who choose to view it. Even if the information is kept private, it can be hacked easily on unsecured sites. Other information, such as texts, emails, GPS location, and Google searches are incredibly difficult to find and hack, due to the resources available to the companies safeguarding the data. This information is not stored in a user-friendly way, so if somebody wishes to acquire this information they must not only be a professional hacker but must also know exactly what they are looking for.

Generally, it would be useful for the average individual to make a conscious effort to limit use of social networking sites, post only information they are comfortable with everybody (including employers, coworkers, friends, enemies, and strangers) viewing online, check privacy settings periodically, and provide unsecured networking sites with vague or false personal information. While it is true that other personal information such as Google searches and credit card data is also present online, the majority of internet users need not worry about others accessing this information: users should instead focus on controlling the availability of more accessible, vulnerable personal data when possible.

Feel free to share your thoughts on internet privacy and related topics below. I look forward to hearing from you.

Light Bending Silicon Chip is Created: Can Function as a Small Projector

At Caltech, a Ali Hajimiri and his group researchers have created a silicon chip that can act as a projector that is lens-free. The results of this research was shared recently: on March 10.

This is a picture of the silicon chip. Photo Credit: Ali Hajimiri/Caltech. Please click the image for more information.

 

In order to understand what is unique about this new way of projecting, one must first understand how regular projectors we use today work. On a very basic level, a beam of light is passed through a very small image. Lenses are used to map each point to a matching, larger point on a bigger screen. To find out more about how projectors today work, click here.

In this new chip, lenses and bulbs are not needed. This is indeed an advantage, because it reduces costs and allows for the production of a smaller device. This chip utilizes what is known as  “integrated optical phased array” (OPA) to project the image. The light source for this chip is a laser diode.

You may find yourself wondering how this new chip works. In the experiments performed at Caltech, the researchers controlled the coherence of light to bend light waves on the edge of the chips, in a sense. The OPA chips change the timing of the light waves, which results in the beam of light changing direction. This process is relatively complex, as there are many different array beams that must merge to create a single beam of light and, consequently, a spot on the screen. Unlike projectors of the past (which were mechanical in nature), this chip is electronic, making it possible for all of the above processes to occur very quickly.

To learn more about the specifics of how this chip works and was created, please visit this link.

In the experiments, the researchers used infrared electromagnetic radiation to display the images rather than light from the visible spectrum. However, there are known ways to extend this technology in such a way that it functions with light from the visible spectrum.

This picture shows the projection of the letters “CIT” using the chip. This projection is one of infrared radiation. Credit: Ali Hajimiri/Caltech. Please click the image for more information.

Below are two very short videos showing the projection of letters using infrared light.

The projection of triangles using infrared radiation. Credit: Ali Hajimiri/Caltech

A projection of the letters “CIT” using infrared radiation. Credit: Ali Hajimiri/Caltech.

There will be various applications for this technology in the future. For instance, such a chip could be integrated in cell phones in order to allow for widespread use. Furthermore, the chip could be used in mapmaking, robotics, geographical measurements, and positioning. Ali Hajimiri said “But I don’t want to limit the device to just a few purposes. The beauty of this thing is that these chips are small and can be made at a very low cost—and this opens up lots of interesting possibilities”.

This technology is far from perfect, but I believe that it could be very useful in the future. The cost of projectors would most definitely be reduced and I know that I would personally want to have such a chip embedded into my phone, as it has the potential for being useful in many situations. For instance, if I were with a large group friends or colleagues and suddenly remembered that I had wanted to show them a video or presentation, it would be possible for me to project this presentation onto a wall or flat surface in the room, avoiding the chaotic situation that might result if the chip were not on my phone and a large number of people attempted to surround me to view such a video or presentation on my phone screen.

Please share your thoughts on this invention below. Would you want to use such an projector yourself? Do you believe it would be useful? What other possible applications do you see for this device? Have you heard of any similar or related research?

 

Nanomotors: Controlled for the First Time in Cells

A group of scientists at PennState have managed to control the movement of gold nanorods—little shards of metal 3 micrometers long and 300 nanometers in diameter—inside living human cells. These nanomotors have the ability to convert energy into movement. In this particular experiment, nanomotors were implanted in HeLa cells—a type of cancerous human cervical cell—set in motion using ultrasonic waves, and guided magnetically. When the ultrasonic waves were emitted at a relatively low frequency, the nanomotors had minute effects on the cells. However, when the power was higher, the nanomotors encountered and destroyed organelles. These nanomotors could be manipulated in such a way as to blend together all cell organelles or even to rupture the cell membrane—in effect destroying the cell. In addition, the nanomotors could be controlled more delicately using magnetic forces.

Gold nanomotors inside a HeLa cell are shown above. The arrows signal the path of the nanomotors. Photo credit: Mallouk lab, Penn State University

The first chemically chemically powered nanomotors were developed roughly ten years ago. However, they needed harmful, toxic fuels in order to function. They were also incapable of movement when placed within biological fluid, making their use in human cells unfeasible.

So what changed? Well, these new and improved nanomotors are capable of transforming acoustic, ultrasonic energy into mechanical movement (rather than relying upon toxic fuel). These ultrasonic waves had the capability of controlling whether the nanomotors moved forward or spinned. An additional benefit of using ultrasonic energy is that the nanomotors have the capacity of moving individually—they do not all have to move in the same pattern.

During this experiment, the cells responded in ways that were before unseen. Tom Mallouk, a researcher that was on the team that developed the chemically powered nanomotors ten years ago as well as the team that developed the more recent acoustically controlled nanomotors, said “This research is a vivid demonstration that it may be possible to use synthetic nanomotors to study cell biology in new ways. We might be able to use nanomotors to treat cancer and other diseases by mechanically manipulating cells from the inside.”

Gold Nanorods inside HeLa Cells (Credit: Mallouk Lab, Penn State University)

The possible applications of these nanomotors are varied and plentiful. As mentioned above, nanomotors could become a possible treatment option for cancer. The ability these nanomotors to move separately from one another would be essential for the utilization of nanomotors to eradicate only cancerous cells while leaving healthy cells unharmed. Other potential uses of nanomotors would include performing surgery within the cell, distributing drugs to cells and tissue, as well as many additional, as well as a number of different possibilities that have yet to be proposed. Mallouk stated “There are lots of applications for controlling particles on this small scale, and understanding how it works is what’s driving us.”

These nanomotors appear to be incredibly promising; however, the suggested applications are still something of the future. As of now, trials using nanomotors to treat cancer have not begun. Regardless of this fact, and of the fact that cancer treatment is incredibly complex and requires not only destroying—but also identifying—cancerous cells, the ability to control the movements of motors on such an incredibly small scale in humans will definitely be an asset. Complications may occur; however, this research is still significant and incredible.

Some may take time to point out the fact that this technology could, in some cases, be misused. There are those who see the potential for a biological weapon that would devastate cells coming about from this newfound ability to manipulate nanomotors in humans. Personally, I find this unlikely. As of now, the technology used to create and direct nanomotors in human cells is incredibly expensive and time consuming, making it an inefficient choice. Additionally, I do not hold the opinion that scientific progress should be stalled or viewed in a negative light because of the possible misuse of technology; people who search only for negative, damaging ways to use inventions will always exist. Discontinuing scientific progress would not be a solution to that issue and would undoubtedly have more negative than positive repercussions.

I believe that a continuation of this nanomotor research, as well as similar research, should be funded in order for us to attain the maximum possible benefit such research could provide.
What is your opinion on this matter? Where do you think this technology might take us in the future? Should further research be supported or discouraged?

 

Sources and additional reading:

Clark, Jack. “Rise of the (tiny) Machines: US Boffins Make Nanomotor Breakthrough.” The Register. N.p., 10 Feb. 2014. Web. 24 Feb. 2014. <http://www.theregister.co.uk/2014/02/10/nanomotor_breakthrough/>.

Sanders, Robert. “Physicists Build World’s Smallest Motor Using Nanotubes and Etched Silicon.” Berkeley.edu. UC Berkeley News, 23 July 2003. Web. 24 Feb. 2014. <http://www.berkeley.edu/news/media/releases/2003/07/23_motor.shtml>.

Weidner, Krista. “Nanomotors Are Controlled, for the First Time, Inside Living Cells.” Eberly College of Science. PennState, 10 Feb. 2014. Web. 24 Feb. 2014. <http://science.psu.edu/news-and-events/2014-news/Mallouk2-2014>.