Category: Science News

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One printed heart, please

It goes without saying that 3D printing is cool*. The ability to think up any three dimensional structure, design it in a 3D design software and have it materialize blows my mind. Granted, I’m making it sound like it’s a very easy and fast process and I know that’s often not the case, but I also know that for a lot of engineering and physics laboratories, the ability to relatively quickly print a model or prototype for anything is extremely useful. In addition, it’s an amazing educational resource. You can print model organs, molecular structures, planets, … and have something physical to show or throw around during a science demo.

Just to name a few reasons why 3D printing is cool.

What is possible even cooler is the potential of printing tissues and organs. And now, for the first time according to a group of researchers in Tel Aviv, it has happened: a complete 3D heart was printed.

They started with some cells isolated from a sheet of fatty tissue from a human patient. These cells were reprogrammed to what’s called pluripotent stem cells. Pluripotent stem cells have the potential to give rise to many different cell types , depending on the biochemical cues they get – for example by changing the formulation of the culture media, which contains nutrients, hormones and other components to “feed” the cells.

In this case, the cells were driven towards being heart muscle cells and blood vessel cells. By mixing these cells with a personalized hydrogel, consisting of collagen (remember, from the reindeer eyes?) and glycoproteins (proteins have a sugar molecule connected to it), the researchers created a “bioink”, a material that could be used to print cardiac tissue in the same way a 3D printer prints 3D structures using a plastic “ink”.

3D printing a mini-heart (image credit AFP or licensors)

While the 3D printed heart – currently around the size of a rabbit’s heart – cannot beat yet, the possibility to be able to print custom organs, starting from a patient’s own cells and therefore eliminating an immune response, is of major importance for medical applications. To enable heart function, the heart cells would have to be taught how to contract in an organized manner, and create a beating heart.

Beating has already been achieved in heart organoids. Organoids are little mini-organs grown in a petri dish, that mimic the organization and function of an organ in a living organism. The difference between 3D printed organs and organoids, is that organoids are allowed to form their own structure and cell types, driven by the media cocktail they are given, while 3D printing positions already differentiated cells in a 3D scaffold. Heart organoids, starting from one or a few reprogrammed cells, grow into structured groups of cells that spontaneously start beating.

Organoid hearts beating

These organoids, however, don’t really mimic the structure of the heart unless you “force” structure by growing these mini-hearts in a mold, basically geometrically confining the cells to form a predefined structure.

A model of a pumping heart was developed last year, creating an in vitro biomimetic system that could help with drug discovery and studying cardiac diseases. While it doesn’t look as much as a heart as the 3D printed one developed by the Israeli research group, it’s still pretty amazing to watch this little blob of tissue beating under electrical stimulation:


In any case, I hope to see a combined version of all of the above: a 3D printed, functional heart. Nevertheless, this first (though debatable if they actually were the first) 3D printed heart is pretty awesome and has a lot of potential applications in medicine and clinical research. Not to mention that it looks pretty cool:

3D confocal image of the printed heart (Advanced Science, scale bar = 1mm)

Sources used:

Noor N., Shapira A., Edri R., Gal I., Wertheim L., Dvir T. 3D Printing of Personalized Thick and Perfusable Cardiac Patches and Hearts. Adv. Sci. (2019), 1900344. https://doi.org/10.1002/advs.201900344

Ma Z., Wang J., Loskill P., Heubsch N., Koo S., Svedlund F.L., Marks N.C., Hua E.W., Grigoropoulos C.P., Conklin B.R., Healy K.E. Self-organizing human cardiac microchambers mediated by geometric confinement. Nat. Comm. 6 (2015), 7413. https://doi.org/10.1038/ncomms8413

Li R.A., Keung A., Cashman T.J., Backeris P.C., Johnson B.V., Bardot E.S., Wong
A.O.T., Chan P.K.W., Chan C.W.Y, Costa K.D. Bioengineering an electro-mechanically functional miniature ventricular heart chamber from human pluripotent stem cells. Biomaterials 163 (2018), 116-127. https://doi.org/10.1016/j.biomaterials.2018.02.024

*Sudden realization that most (if not all) of this blog is me saying “Hey, did you hear about this science thing, it’s really cool!!”

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Supermassive black hole

Step one – press play on this video:

Step two – stare into this picture for the full 3-and-a-half minutes (that’s the length of the song, you’re free to stare for longer):

20190410-78m

Credit: Event Horizon Telescope Collaboration

Step three – find out more…

Oh hey, scientists have taken the first ever picture of a black hole. This is amazing.

Note: I intend to write another blog post this week, I just wanted to share this black hole news!

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150 years of elements

Here’s a riddle for you: what hangs in every chemistry class in middle and high school, leads to the creation of several nerdy t-shirts, and celebrated is 150th birthday yesterday?

Okay, it’s not a very funny riddle. Nor is it a very difficult one. The answer is: the periodic table of elements, first published on the 6th of March 1869 – exactly 150 years minus-one-day ago – by the Russian chemist Dmitri Mendeleev.

Professor scheikunde Dmitri Mendelejev in zijn bureau aan de universiteit van Sint-Petersburg.

Professor Dmitri Mendeleev

From Alchemy to Chemistry

In the olden days, we would have turned to alchemists to ask our questions about fundamental elements and what stuff makes up stuff. Even though alchemy was not really a “science” in the pure sense of the word – it relied heavily on spiritualism, philosophy and even magic – it set the stage for what would later become chemistry. And while alchemists were mostly trying to turn random metallic rocks into gold, or brew an elixir for eternal life, they were the first that attempted to identify and organize the different substances occurring in nature. The Elements.

The earliest basic elements were considered to be earth, water, air, and fire. The discovery of what we might call “chemical elements” really kicked off in 1669 in Germany, by a merchant by the name of Henning Brand. Like many chemists-avant-la-lettre (alchemists), he was trying to discover the Philosopher’s stone. However, like many muggles, he was not acquainted with Nicolas Flamel and did not succeed (Side note: Nicolas Flamel was actually based on a real person!). Instead, while distilling urine – as you would while trying to create eternal life – he discovered a glow-in-the-dark substance: phosphorous. And with that, the element finding had begun.

Chemistry can be considered to have originated in 1789, when Antoine-Laurent de Lavoiser wrote what is said to be the first modern chemistry textbook. In this book, he defined an element as a substance that can not be broken down into a simpler substance. A fundamental particle. This definition lasted until the discovery of subatomic particles (electrons, protons, and neutrons) in the 1930s. Lavoisier’s list of elements included things like oxygen, hydrogen, and mercury, but also light.

Dalton’s symbols of the elements. 1806 (Wellcome Images). Combine numbers 24 and 28 with some gin and get a nice cocktail.

Let’s glaze over most of the 19th century, where multiple different scientists realized that the atomic weights of elements were multiples of that of hydrogen (William Prout) and how there was a certain periodicity in terms of physical and chemical properties when the elements were arranged according to their atomic weights (Alexandre-Emile Béguyer de Chancourtois). The early attempts to classify the elements were based on this periodicity, and eventually, our Mendeleev came along.

“Chemical Solitaire”

The Russian chemist Dmitri Mendeleev is the father of the modern periodic table. In fact, in Belgium, we call the periodic table of elements “Mendeleev’s table of elements”. After (allegedly) playing “chemical solitaire” on long train journeys – quite common in Russia, I’m sure – he came up with a classification method based on arranging the elements by atomic mass and classifying them according to their properties. Elements in one group (column) have the same number of valance electrons: the number of electrons in the outer shell of the atom and available to react with other elements. Elements in the same column therefore from bonds with other elements in the same way, and form similar types of materials.

Because there were some gaps in the table – some atomic weights missing – he predicted the existence of elements that were yet to be discovered, and what their chemical properties would be. And this is what made his classification method so ground-breaking.

And indeed, in 1885 germanium was discovered, with properties – as predicted – similar to silicon. Same for gallium in 1875 (similar properties as aluminum) and scandium in 1879 (similar properties as boron), filling up some gaps in his periodic table.

The periodic table from Osnovy khimīi by Dmitry Ivanovich Mendeleyev, 1834-1907. S.-Peterburg : Tip. t-va “Obshchestvenna︠i︡a polʹza, 1869-1871.

The gaps are filled

Since 1869, the gaps in the periodic table have been filled, and new elements are discovered or created every few years adding to the high end of the table. The last update to the periodic table was in 2016, when the elements nihonium (113), moscovium (115), tennessene (117) and oganesson (118) were added to the list.

So today – okay, yesterday – we celebrated 150 years of chemical element classification, the anniversary of the periodic table of elements, and the collective pain of decades of highschoolers memorizing atomic masses and the number of valance electrons.

The table of elements as usually taught today, with pictures of applications for each element (from https://elements.wlonk.com/index.htm).

Inspired by the coverage by vrt nws.

The interactive table of elements in the cover picture is from
http://periodictable.com/

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A matter of kilos

It’s been the topic of a weighted discussion for quite some time, but today it has been decided: “Le Grand K” will no longer be used to define a kilogram.
“Le Grand K” is not a big box of Special K, but a platinum-iridium cylinder stored by the International Bureau of Weights and Measures in an underground vault in Paris that has defined a kilogram of mass since 1889. There are a few official copies, and many more copies, so each country has their own kilogram to calibrate to.
Last Friday (November 16th) the kilogram has been redefined so it no longer depends on a material object. Because a material object can be scratched, chipped or destroyed. Or stolen. Or accidentally thrown into the bin. And it can degrade – in fact, “Le Grand K” weighs about  50 µg lighter than its six official copies. You don’t really want to gold – ahem, I mean platinum-iridium – standard for weight to change in weight, right?
So now the kilogram will be defined based on a universal, unchangeable constant. Much better, I think you would agree. The constant of choice here is the Plank’s constant, a number that converts the macroscopic wavelength of light to the energy of individual constants of light. Representatives from 58 countries universally agreed on this new definition, so from next year, the kilogram will be constant forever.
The ampere (electrical current), the kelvin (temperature) and the mole (amount of chemical substance) have also been redefined. That means that all seven units in the International System of Units (S.I.) will be defined by universal constants:
meter unit of length
  • Originally defined as a 10-millionth of the distance between the North Pole and the Equator along the meridian through Paris, later as the distance between two scratches on a bar of platinum-iridium metal
  • Since 1983 defined as the distance traveled by a light beam in vacuum in 1/299,792,458th of a second, with 299,792,458 m/s being the universally constant speed of light.
kilogram unit of mass
  • Initially defined in terms of one liter of water, but since as a small ~47 cm3 cylinder stored in a basement in Paris.
  • Now redefined in terms of the Plank constant h = 6.62607015×10−34 J*s (J = kg*m2*s−2)
second unit of time
  • Originally defined as 1/86,400th of a day
  • Since 1967 it has been defined as the time it takes an atom of cesium-133 to vibrate 9,192,631,770 times
ampere unit of electrical current
  • Originally defined as a tenth of the electromagnetic current flowing through a 1 cm arc of a circle with a 1 cm radius creating a field of one oersted in the center
  • Now redefined in terms of the fixed numerical value of the elementary charge e (1.6602176634×10−19 C with C = A*s and second defined as above)
kelvin unit of temperature
  • The centigrade scale was originally defined by assigning the freezing and boiling point of water as 0 °C and 100 °C respectively. Note: absolute zero is the lowest temperature (0K =  -273.16 °C)
  • Now redefined in terms of the Boltzmann constant k = 1.380649×10−23 J⋅K−1
mole unit to describe the amount of substance
  • Since 1967 defined as the amount of substance which has as many elementary particles as there are atoms in 0.012 kg of carbon-12.
  • Now one mole substance contains exactly 6.02214076 × 10^23 particles. This constant is known as Avogadro’s number*
candela unit to describe the intensity of light
  • Originally taken as the luminous intensity of a whale blubber candle in the late 19th century.
  • Since 1979 the light intensity of a monochromatic source that emits radiation with a frequency 5.4 x 1014 hertz and has a radiant intensity of 1/683 watt per steradian in a given direction **
So that was “this week in science.” I’ll leave y’all with a related joke:

kilogram

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Sources/Further reading:

The international system of units: en.wikipedia.org/wiki/International_System_of_Units
The new kilogram was in the news: www.nytimes.com/2018/11/16/science/kilogram-physics-measurement.html and www.theregister.co.uk/2018/11/17/amp_kelvin_kilogram/
Comic from xkcd.com

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* Avocado’s number, however, states that 6.02214076 × 10^23 guacas make up one guacamole. (I knooooow, I already made this joke).
** I have to be honest and say that I have no idea what this all means

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A Nobel Cause

So, the news is out. At least in terms of the sciency Nobel Prizes (sorry Economic Sciences, you don’t really count here), the 2018 Laureates have all been announced, so here’s a short overview of what was Nobel-Prize-Worthy this year:
1. Nobel Prize in Chemistry (press release)
And… *drumroll* the Nobel prize in Chemistry goes to Prof. Frances H. Arnold, Prof. George Smith and Sir Gregory Winter for their contributions to protein biology, where they all worked on directed evolution of proteins.
Directing protein evolution is used to create proteins with a specific function that can be used in biofuel, pharmaceutical, and medicine manufacturing. Half of the Nobel Prize was awarded to Prof. Arnold, who works on directed evolution of enzymes (proteins that are used to accelerate or direct chemical reactions). The other half, that of Prof. Smith and Sir Winter, celebrated a method called phage display. This process uses viruses to develop specific proteins that can be used for medical purposes.
My personal excitement for this prize:
Well, Prof. Arnold is a professor in bioengineering, which is, in my opinion, an underacknowledged field, so that’s pretty cool. And this has nothing to do with the fact that I’ve studied bioengineering. Nothing at all.


2. The Nobel Prize in Physiology or Medicine (press release)
The Nobel prize in Physiology or Medicine was awarded to Jim Allison and Tasuku Honjo for their work in cancer therapy. By now, the concept of “immune therapy” may not sound extremely new anymore. However, just think about how amazing it is: someone’s immune system (in other words, an attack system that is already present in your body) can be used to fight cancer cells (which isn’t really straightforward – cancer cells originate from normal cells so are not detected as “foreign” by the immune system).
My personal interest in this prize: 
First of all, yay for biology completely highjacking the Nobel Prizes. But on the topic: radiotherapy and chemotherapy are both notorious to have a huge amount of side effect. By effectively using the natural defense system of the body, immune therapy usually is a lot less taxing on a patient, which I think is a laudable goal.
https://twitter.com/NobelPrize/status/1046694080883949568


3. The Nobel Prize in Physics (press release)

*Final Drum Roll, please*
The Nobel Prize in Physics is all about lasers (Did you know that LASER is an acronym for “Light Amplification by Stimulated Emission of Radiation? Well, you do know). Arthur Ashkin was honors for his development of optical tweezers (which I will simply explain by referring you to my fabulous friend who has worked with optical tweezers herself) and the other half was awarded to Donna Strickland and Gerard Mourou for their work on laser pulses. The most known application of laser pulses is in laser eye surgery.
My personal input to this prize:
I have two thoughts, first, how has this not won a Nobel Prize yet? Actually, to be honest, I think that quite often when the Nobel Prizes, which is probably why they get a Nobel Prize in the first place. The other thought has to do with the same reason why this prize has been in the press a lot: it has been 55 years since a woman won a physics Nobel prize. Only two other women have a Nobel Prize in Physics to their name: Marie Skłodowska-Curie (obviously!) and Maria Goeppert-Mayer (go google her, now).
https://twitter.com/NobelPrize/status/1047061973966512130
Some thoughts on women and Nobel Prizes
Historically, science has always been pretty male-dominated. And even now, women are underrepresented in research: worldwide the female share of persons employed in R&D is approximately 30% and I will not even get into high-level academics here.
In terms of Nobel Prizes, as of this year, there have been 49 women who have won Nobel Prizes (that’s all of them), compared to 844 men. In the sciency fields, five women have won the Nobel Prize in Chemistry (2.8%), twelve have won the Nobel Prize in Physiology or Medicine (5.6%), and – as stated – three have won the Nobel Prize in Physics (1.4%). Actually, only one woman has won the Nobel Memorial Prize in Economic Sciences (also 1.4%), but that doesn’t really count as a science anyway!
In any case, none of the Nobel Prizes have a good track record, and it makes me a bit sad that “First woman Physics Nobel winner in 55 years” is a news headline, but ah well, we may have come some part of the way but we are not there yet.
And until we are, having positive role models of all shapes and sizes and sexes for STEM fields is crucial. As a wannabe science-communicator, or science-populizer if you will, one of my aims is exactly that. So that every child can look up to a scientist and think “that could be me!”
And – even if I say so myself – I think that’s a pretty noble cause.

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An ignobel cause

Disclaimer: if you’re a bit hungry and/or know that reading about spaghetti will make you hungry, I suggest you go eat some spaghetti before you continue reading… But if you do, keep at least a few strands uncooked, you might need it later on.

An odd article popped up on my go-to news site the other day. And then the day after that, an article on the same topic popped up in the newspaper I was reading. It was an article reporting on the science of breaking an uncooked spaghetti.

No, I’m not joking.

And apparently, the research solves a decade-old problem. I never knew spaghetti could pose a decade-old problem, except for maybe the secret spaghetti-sauce recipe of an Italian-American family but that’s a century-old problem, I would say.

So if you’d go into your kitchen now, take a strand of uncooked spaghetti, hold it at the ends, and start bending it until it snaps, you will see what this mystery is all about. Most probably, you have now ended up with three or more bits of spaghetti. If you are super bored or think snapping spaghetti is super-fun (this is what Richard Feynman apparently thought), you can try it again. And you will notice the spaghetti almost never snaps into two pieces. Or you can just take my word for it…

In 2005, some French physicists came up with a theoretical solution to why spaghetti never breaks into two, because this unsolved mystery Richard Feynman broke his head about merited some further research…
When a very thin bar (or strand of spaghetti) is being bent, this will cause the strand to break somewhere near the middle. This first break will cause a “snap-back” effect which essentially causes a vibration to travel through the rest of the strand, causing even more points of fracture, which results in three or more pieces. In other words, is very rare to end up with exactly two pieces of spaghetti.

These French researchers were rewarded with an Ig Nobel prize for their finding. An Ig Nobel prize is a prize that is rewarded “for achievements that first make people LAUGH then make them THINK” and also the reason for my best quiz achievement ever.*

crack-control-1
Experiments (above) and simulations (below) show how dry spaghetti can be broken into two or more fragments, by twisting and bending. (Image: MIT)

And now, years later, mathematicians from MIT have added to that research by coming up with a way to ensure a dry spaghetti strand does break exactly in two: by first twisting the spaghetti before bending it. The twisting part causes stresses in the spaghetti strand that counteract the snapback effect when it eventually breaks. When the spaghetti does break in to, the energy release from a “twist wave” (where the spaghetti pieces untwist themselves) ensures there is no extra stress that would cause more fracture points. So there we go: the spaghetti breaks in exactly two pieces as long as you twist it enough.

crack-control-2
Experiments (above) and simulations (below) show how dry spaghetti can be broken into two or more fragments, by twisting and bending. (Image: MIT)

Now, this theory isn’t only limited to breaking spaghetti. Understanding stress distributions and breaking cascade also have some practical applications, according to the authors: the same principles can be applied to other thin bar-like structures, such as multifibers, nanotubes, and microtubules.
Now, if you haven’t already, go get yourself some spaghetti.

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* The question: who has one both an Ig Nobel and a Nobel prize and for what?
The whole table looked very confused and I just said very confidently “André Geim, levitating a frog and graphene” so it turns out a degree in nanotech is super useful for winning quizzes. (Actually, I’m not even sure we won and I doubt it was thanks to me answering that one question correctly, but I’m pretty sure I will never live up to that moment ever again.)

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Octopuses suck! (but not like that)

You might know the frustration of trying to get a suction cup to stick: cleaning the sucker and surface over and over again, pushing on the sucker for increasing amounts of time and with increasing amounts of force… But nothing helps, the basket of shower gels and shampoos, or whatever you’re trying to attach to a wall/window/door (or maybe you are trying to climb a tower) just slowly slides down – if you’re lucky – or falls to the ground – on your toes, if you’re not so lucky.

Well, there might be some hope. Researchers are looking to nature to find a solution to this everyday frustration – because I’m positive this was the incentive: minimising shower rage. There is a whole field based on nature-inspired solutions and products, mostly grouped under the name Biomimetics, because why would you try to reinvent the wheel if nature has evolved a useful means of transportation?

Back to the suckers. In June, I came across a News&Views article that made me do a double take. You see, I had a brief moment of surprise when I thought the Nature journal had taken a liking to hentai (if you don’t know what this is, please do not google it, you have been warned). But it was not what I thought; “How to suck like an octopus” dealt on materials science, and how to make rubber sheets that can stick to surfaces. In other words: how to make better suckers!

It turns out that octopuses use suction cups to attach to rocks and to grab things. And it turns out the special shape of their suckers enhances that adhesion. Boom, let’s try and create a material that does the same!

Inspired by Octopus vulgaris, researchers tried to recreate the ideal adhesive material that sticks well to surfaces but also is able to detach easily. Octopus vulgaris‘ trick is a dome-shaped bulge at the bottom of the suction cup (see figure). This “dome in a cup” structure – mimicked by micrometre-sized hole with a dome in it (see figure, again) – enhances adhesion to wet surfaces by providing capillary forces between the dome and the substrate.

On dry surfaces, the presence of the domes does not increase adhesion but doesn’t cause any decreased adhesion either. The only difference between the octopus suckers is that octopuses have muscles in the suckers to flex, expand and contract them, increasing control of the adhesion and detachment. There are still some things to mimic then; it’s always nice to have something for the “Future Work” bit of a paper.

I think biomimetics is like super cool, though I have to admit that sometimes the applications seem unrealistic or too far-fetched; in this case, the authors suggest applications in manufacturing – transport of materials – and biomedical applications such as wound dressing. However, I still believe there is great value in biomimetic research: better understanding – the biomimetic device can teach us of the workings of the in natura equivalent (I know that’s not what in natura means) – and it’s just fun to do!
The News&Views author agrees:

“Applications aside, understanding and mimicking the fundamental science of attachment strategies used by sea creatures can just be plain fun.”

546358a-f1
Octupus vulgaris suckers contain dome-shaped bulges. Flexible biomimetic rubber sheets containing an array of micrometre-sized holes with a bulge in each hole.

References:
Original Letter: http://www.nature.com/nature/journal/v546/n7658/full/nature22382.html
Suction Cup Guy: https://www.youtube.com/watch?v=7XCk3AtUbvA