Beer-brewing ‘biobots’ could boost the drinks industry by speeding up fermentation. Researchers in Czechia encapsulated yeast and iron oxide nanoparticles in a biocompatible polymer to create self-propelling biobots, which can be retrieved from beer samples magnetically – eliminating the need for filtration steps.
To read the entire article, click here: https://www.chemistryworld.com/news/biocatalytic-biobots-brew-beer-better/4017318.article
Two coumarin compounds with nearly identical structures but contrary fluorescent properties have been isolated from the orange climber plant. One may find use in biomedical imaging due to its unconventional behaviour when aggregated in solutions.
To read the entire article, click here: https://www.chemistryworld.com/news/orange-climbers-make-fluorescent-blue-molecules/4017351.article
A new analytical method has enabled continuous real-time monitoring of the biosynthesis of sialic acid, an important component of cell surfaces, via NMR. Described as a magnifying glass by lead researcher Christian Hackenberger from the Leibniz Research Institute for Molecular Pharmacology in Germany, the NMR technique allowed them to observe individual enzymatic steps and, for the first time, directly measure their conversion velocities in situ.
Read the entire article here: https://www.chemistryworld.com/news/nmr-reveals-sialic-acid-biosynthesis-in-real-time/4017299.article
Using dental calculus from Neanderthals and Palaeolithic humans, researchers have reconstructed ancient microbial genes and engineered modern bacteria to produce their previously unknown metabolites. The approach will allow natural product researchers to ‘add a new dimension and go back in time’ according to bioorganic chemist Pierre Stallforth from the Hans Knöll Institute in Jena, Germany, who led the project.
To read the full article, click here: https://www.chemistryworld.com/news/ancient-microbial-natural-products-reconstructed-from-neanderthal-dental-plaques/4017421.article
Two newly uncovered documents offer a more nuanced account of Rosalind Franklin’s contribution to the discovery of the DNA double helix. The findings challenge some of the prevailing narratives surrounding the discovery for which James Watson, Francis Crick and Maurice Wilkins received the Nobel prize in 1962.
By many popular accounts, the key insight that helped crack the mystery of DNA’s structure came when Wilkins showed Watson an x-ray image from Franklin’s lab without her permission. Writing in Nature, researchers Matthew Cobb and Nathaniel Comfort note that this image, known as photo 51, is ‘treated as the philosopher’s stone of molecular biology’ with Franklin often painted as having ‘sat on the image for months without realising its significance, only for Watson to understand it at a glance’.
However, during a recent visit to an archive at Churchill College in Cambridge, UK, Cobb and Comfort discovered two previously overlooked documents – an unpublished news item that was drafted for Time magazine at the time of the double helix discovery, and a letter from one of Franklin’s colleagues to Crick – that cast new light on the discovery of the double helix. ‘Franklin did not fail to grasp the structure of DNA. She was an equal contributor to solving it,’ they write.
To read the entire article, click here: https://www.chemistryworld.com/news/overlooked-documents-shed-new-light-on-double-helix-discovery/4017384.article
Generic drugs offer low-cost alternatives to brand-name drugs and account for over ¾ of the prescriptions filled in Canada. Despite this, many people have lingering doubts, fears or negative perceptions of generic equivalents. Why?
According to Health Canada, a “generic drug is pharmaceutically equivalent to the brand name drug: it contains the identical medicinal ingredients, in the same amounts and in a similar dosage form. Generic medications may have different non-medicinal ingredients than the brand name drug, but the company must show that these do not affect the safety, efficacy, or quality of the drug compared to the brand name drug.”
Simply put, in all the ways that count, generic drugs are the same as name-brand options but cost significantly less. Assuming a generic version of their medication is available, why would a consumer choose the pricier option?
According to various surveys and studies, there are a few reasons. A big one is brand trust. Just as some people favour Ford vehicles or Apple computers, pharmaceutical companies have brand recognition and inspire brand loyalty. Whether conscious or unconscious, warranted or not, due to branding, experience or something ephemeral, patients often express a preference for specific brand names.
This ties in with another fairly major factor, how long a drug has been around. Several studies have shown that consumers prefer older drugs, even when newer drugs are equally safe and efficacious. In most countries, generic versions of a pharmaceutical aren’t approved by regulatory authorities until the original manufacturer’s patent protection has worn off. Typically, this amounts to somewhere between 8 and 15 years. In Canada, the US and the UK, drug patents are 20 years in length. However, the time taken to test drugs and get them approved for sale eats into this monopoly period, meaning that by the time a new drug gets to market, a generic version is typically about a decade away.
Even though generic drugs are pharmaceutically equivalent to their name-brand counterparts, they still undergo rigorous safety testing. Nonetheless, the perceived age of the name-brand option can influence how patients feel about the generic choice. A 2020 study found that “although there is a small segment of the population that chooses the newer option, believing it to be of greater efficacy, most consumers believe that an older drug is both safer and more efficacious.” Even when participants were given a “no preference” option, more than half still opted for the older medication. The researchers found a “consistent pattern in which, on average, participants thought that older products were both more effective and safer, even when they were clearly informed (and they know they were informed) otherwise.” Essentially, consumers’ goodwill and trust in a drug seem to grow with age.
Another element of this situation is revealed by a 2020 study that found patients more willing to choose generic drugs for conditions perceived to be less serious, like the flu, compared to those considered more serious, like a cardiac disease. This only further implicated the perception of efficacy and safety in why people choose name brands over generic ones.
This apparent trust of age is echoed in the findings of a 2022 study that found COVID-19 mRNA vaccines judged as safer and more effective when perceived to be older. By changing the events and discoveries shown on a timeline, researchers were able to influence how old participants perceived mRNA vaccines to be. They found that “accounting for participants’ vaccination status, Covid-19 mRNA vaccines received more support – they were judged as better, safer, and more as something people ought to take – when the technology undergirding their development was perceived as having longer existence.”
Image source: https://www.tandfonline.com/doi/full/10.1080/15534510.2022.2116105
Perhaps the most changeable factor in consumers choosing brand name is also one of the most predictable: education. When patients are sufficiently informed on the realities of generic drugs, the reasons not to pick them mostly evaporate. For the vast majority of people in the vast majority of situations, generic drugs offer a cheaper choice with no drawbacks. A 2016 survey found that roughly 1/3 of participants did not fully understand why both generic and name-brand drugs existed, and this comprehension was not affected by education level.
While the landscape is generally shifting towards a positive attitude towards generic drugs, work remains to be done to get the message across fully. If in doubt, ask your doctor if generic versions of your drugs are right for you. You could get a positive surprise on your next pharmacy bill!
This article was written for the McGill Office of Science and Society. View the original here: https://www.mcgill.ca/oss/article/medical/generic-drugs-and-ambivalent-attitudes
Even if it might gross us out now, experts predict that edible insects will play a significant role in our future diets. Not only are these bugs rich in protein and nutrients, but they can also be farmed more sustainably. For example, farmed crickets have a water footprint roughly 1/3 the size of beef cattle, require 50-90% less land, and emit 100 times less greenhouse gas during the farming process. In addition, where most of a cow is inedible to humans, roughly 80% of a cricket can be eaten, meaning less waste.
All things considered, it is in our best interest to get comfortable with eating insects. Unless you’re allergic to shellfish, that is.
Shellfish allergies are highly prevalent throughout the world, particularly in places where consumption is high. It’s estimated that 2% of people worldwide show immune responses to shellfish. In the U.S., roughly 6.5 million individuals have a shellfish allergy, making it twice as common as a peanut allergy. Shellfish plus seven other common allergens (milk, eggs, fish, tree nuts, peanuts, wheat and soy) make up 90% of food allergies in the U.S. that are not outgrown after childhood.
It’s not only through eating shellfish that one can have an allergic reaction. Occupational exposure at shellfish processing plants can cause reactions, often just through inhaling the airborne particles of crustaceans.
Unfortunately, the edible-insect revolution is not very welcoming for the many affected by a shellfish allergy. Upon consumption of crickets, mealworms or other insects, individuals with shellfish allergies have a good chance of having an allergic reaction. This is even true for the occupational exposure route, with reports of cricket farm or pet store workers sensitive to shellfish having reactions.
The high potential for cross-allergic reactions between insects and shellfish might only make sense once you look at their phylogenetic tree. Shellfish is a colloquial term encompassing any ocean-dwelling animal with an exoskeleton. Almost none of them are actually fish. Bearers of the shellfish moniker come from three different phyla: Mollusca, containing mollusks like snails, clams, and octopi; Echinodermata, containing echinoderms like sea urchins and sea cucumbers; and crustaceans like shrimp and lobster, which are actually a subset of the phylum Arthropoda.
Photo source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5306157/
You might know arthropods as all the things we typically call “bugs,” like spiders, millipedes, and all sorts of insects. Crustaceans like crayfish or prawns are, quite literally, just the bugs of the sea. With this evolutionary relationship in mind, it’s easier to imagine how immune systems often fail to differentiate between bugs of the land and the ocean.
Photo source: https://www.animalwised.com/classification-of-invertebrates-chart-with-definitions-and-examples-3657.html
Most shellfish allergies are due to the immune system reacting to proteins. There are a few different proteins in shellfish responsible (around 34), including arginine kinase and sarcoplasmic calcium-binding protein, but the overwhelming majority of those with shellfish allergies show sensitivity to the protein tropomyosin.
As Dr. Zachary Rubin, pediatric allergist, wrote to me, “The majority of people allergic to shellfish are allergic to a protein called tropomyosin, which is also found in many insects, so it’s not usually a good idea to consume insect-containing foods if you have a shellfish allergy.”
If you’ve studied biology or seen the famous “The Inner Life of the Cell” animation, you might recognize tropomyosin as one of the proteins integral to our muscles contracting. Without tropomyosin, I couldn’t move my fingers to type this article. But if tropomyosin is found in the proteins of most animals, why are so many people allergic to shellfish tropomyosins but not other animal tropomyosins?
It comes down to the sequence of amino acids that make up a tropomyosin protein. You can think of a protein as a chain, with each individual link being an amino acid. A protein chain can be constructed of many different combinations of amino acids in various orders to create countless distinct proteins with unique properties.
All tropomyosin proteins are similar to a certain degree—otherwise, they wouldn’t be tropomyosin proteins—but even working within these bounds, tropomyosin is afforded significant variation in its amino acid sequence between different animals. Some animals are more similar to others. Across various crustacean species such as prawns, crabs, and lobsters, amino acid identities can reach 95–100% similarity. The tropomyosin amino acid sequence is well preserved across shellfish, even though they belong to two different genetic phyla: Arthropoda and Mollusca.
Tropomyosin is the culprit allergen for cross-reactions between those allergic to shellfish and insects like crickets, fruit flies, grasshoppers, cockroaches, locusts, and dust mites.
One 2020 study found that certain insect species elicited less of an immune response from shrimp tropomyosin allergic patients. Mealworm larvae, waxworm larvae and superworm larvae may represent less allergenic insect options.
Another specific aspect of shellfish tropomyosins that may contribute to their allergenicity is their high thermostability. When proteins are heated, most will melt. Typically, this means that they are no longer active. Having lost their 3D structure, the proteins can’t be recognized by receptors or other important molecules and isn’t detectable by the immune system.
Treating proteins under high heat to denature them can be a strategy for making hypoallergenic products. The tricky thing is that the temperature needed to denature changes based on the protein. For example, tropomyosins happen to have very high melting points. This thermostability is thought to contribute to the highly allergenic nature of these proteins since treatment with heat, or even high pressure, isn’t sufficient to render them anallergenic.
Unfortunately, due mainly to tropomyosin and a handful of other allergenic proteins, the edible insect revolution is not for those with shellfish allergies. Given the popularity of alternative protein choices for pet foods, you may want to keep the shellfish-insect connection in mind when choosing kibble for your furry friends.
This article was written for the McGill Office of Science and Society. View the original here: https://www.mcgill.ca/oss/article/health-and-nutrition/edible-insect-revolution-not-those-shellfish-allergies
The difference between hypoallergenic and anallergenic pet foods is subtle but important. The Greek prefix hypo- means “lacking” or “less.” Hence, someone who is hypothermic is lacking in heat, and someone who is hypoglycemic has less blood glucose than they should. The prefix a- (or an- when it proceeds a word that starts with a vowel) is also Greek but means “no,” “not,” or “absence of.” We see this in terms like apolitical (not political) or anorexia (absence of appetite). Thus, hypoallergenic dog food contains fewer allergens, whereas anallergenic dog food contains none (or as close to none as possible).
What does that actually mean for pet food? Well, for most cats and dogs, proteins are the primary allergen, so hypoallergenic foods tend to use partially hydrolyzed proteins or proteins that have been broken down into smaller pieces and are therefore less likely to be recognized by an animal’s immune system, triggering a reaction. They tend to use a single source of protein instead of a blend and a single source of carbohydrates. Hypoallergenic pet foods often avoid the most common allergens for cats or dogs, sometimes employing specific parts of these animals—hydrolyzed chicken liver is common—or novel and “weird” protein sources like kangaroo, rabbit, or soybeans.
The problem is that roughly 25-50% of dogs will still have allergic reactions when fed hydrolyzed diets derived from proteins they’re allergic to. This may be due to incomplete hydrolyzation, leaving protein fragments still big enough to be recognized by the immune system, or even just cross-contamination from some part of the manufacturing process. For dogs like this, veterinarians often turn to anallergenic diets.
Proteins are long chains of amino acids. Their mass is measured in a unit called a Dalton (Da), or more commonly, a kilo-Dalton (kDa) because scientists prefer working with smaller numbers whenever possible. Protein masses can vary widely. For example, insulin has a mass of roughly 5.8 kDa, whereas ATP synthase, the enzyme responsible for powering everything we do, has a mass close to 600 kDa. Alcohol dehydrogenase, the enzyme that processes any alcohol we drink, weighs roughly 170 kDa.
There isn’t a consensus on how big a protein needs to be to potentially trigger an immune response, but we can confidently say that the smaller the protein, the lesser the chance. Hypoallergenic dog food tends to have proteins in the 3-15 kDa range. Conversely, Royal Canin’s Anallergenic food—debuted in 2012 after over a decade of research—was the first pet food considered to contain extensively hydrolyzed proteins. It contains proteins that are 95% less than 1 kDa and 88% broken down to the level of single amino acids!
In one randomized, double-blind crossover study of 10 dogs with cutaneous adverse food reactions, the Royal Canina Anallergenic diet did not trigger an allergy flare-up in a single participant. In contrast, a hydrolyzed chicken liver diet (a typical protein source for hypoallergenic dog foods) triggered a flare-up in 40%.
Despite being a feat of scientific engineering designed to help dogs and cats get relief from a condition without many other treatments, there remains a degree of controversy around Royal Canin’s Anallergenic food. Why? Because its protein source is hydrolyzed poultry feathers.
Pet food marketing has long relied on messages about feeding your dog as you would the other members of your family or avoiding “filler” ingredients. Unfortunately, this has resulted in demonizing ingredients like corn meal or hydrolyzed poultry feathers, even when all science supports their inclusion. Despite appeal-to-nature infused commercials referring to domestic dogs as “wolves” or “carnivores,” your Shih Tzu has evolved quite a bit from her wolf days and has different dietary requirements.
Dogs are not carnivores and haven’t been for thousands of years. They can digest grains quite well and benefit significantly from modern advancements in food processing, just like humans. Raw diets are dangerous for a multitude of reasons, and just because you wouldn’t want to eat an ingredient like hydrolyzed poultry feathers doesn’t mean it isn’t perfectly beneficial to your pet. Not to mention, as the poultry feathers are so extensively broken down before being included in kibble, it makes about as much sense to consider them feathers as you’d consider a single brick a cathedral.
All of the dogs in the above-mentioned crossover study readily ate the feather-based food, and such diets seem acceptable even for the more traditionally discerning cats. Despite claims to the contrary, hydrolyzed poultry feathers are well-digested by both cats and dogs.
Other attempts to demonize poultry feathers as a source of protein rely on characterizing them as a “waste product” of human meat processing—as if that’s a bad thing. For sustainability purposes, utilizing every part of an animal is far preferable to disposing of a perfectly functional ingredient. Claims that Royal Canin is only using feathers to benefit their own pockets are equally nonsensical, given how expensive the extensive hydrolyzation process is, the extensive research and development funding that went into perfecting it, and how much cheaper it would be to continue to use the conventional protein sources they already have.
Anallergenic food is a powerful tool for veterinarians and pet owners to diagnose and treat severe pet allergies that, prior to its invention, often had no great treatments. The demonization of by-products, highly processed ingredients, or whatever else you want to call hydrolyzed poultry feathers is unscientific rubbish that will almost certainly lead to pets who would benefit from this food not getting it. It’s high time we overcame our fear of the unknown and instead marvelled at how science can find unique new solutions to age-old problems.
This article was written for the McGill Office of Science and Society. View the original here: https://www.mcgill.ca/oss/article/pet-allergies-feathers-may-be-unexpected-solution
Everyone seems to have an opinion on making the best cup of tea. People who have weighed in on this topic range from royal butlers to George Orwell, but despite many claims of it being definitively settled—often by science—the debate rages on.
From the ideal water temperature to the source of the tea leaves, the best material for a pot (china, earthenware, or pewter, according to Orwell, never silver!), the best shape of a cup, or whether it is sacrilege to add sugar, there are a lot of variables in brewing tea. However, one of the most hotly contested ones is not whether to add milk or not, but in what order.
Adding milk to tea has a few benefits, according to the experts. It can help counteract the tannin’s astringent or bitter aspects and adds a few calories and nutrients to an otherwise nutritionally bereft beverage. Modern research also shows that adding milk can decrease the staining effects of tea on teeth and, presumably, mugs and pots as well.
A commonly circulated theory posits that first pouring milk into a china teacup helps avoid the heat shock of directly filling it with hot fresh tea and stops low-quality china from cracking. Some sources claim that the practice of pouring tea into a cup before milk, therefore, became a subtle way to brag about the quality of your china. While it’s hard to validate this theory, tea before milk is the preferred pouring order of the British Royal Family, who are likely to take an opportunity to boast their riches.
Regardless of its origins, almost all guides and sources now agree that tea should be poured into a cup first and milk (if desired) second. As for the claims that science has somehow settled this debate, besides a few industry-funded “studies” (really more like PR stunts) and a press release from the Royal Society of Chemistry based on research that was either never done or never published, I can’t find any actual scientific discussion of whether it’s better to add your milk or tea to your mug first.
Although, if a research group wants to study this in the future, they’ll likely benefit from ISO 3103, a publication from the International Organization for Standardization (ISO) that details standardized steps with which to brew a cup of tea for the purposes of comparison. The ISO is a non-governmental organization that exists for the express purpose of developing standards that are applicable across all 167 member countries for technical and manufacturing purposes. ISO 3103 was approved by all member countries, with the exception of Ireland, which objected on technical grounds due to the omission of a teapot warming step.
As I said, almost everyone seems to have strong opinions on this topic. I think I’ll be keeping my tea-brewing method to myself.
This article was written for the McGill Office of Science and Society. View the original here: https://www.mcgill.ca/oss/article/history-you-asked/should-you-add-milk-tea-or-tea-milk
his year’s [Nobel] Prize in Chemistry deals with not overcomplicating matters” says Johan Åqvist, Chair of the Nobel Committee for Chemistry. It has a simple and catchy name: Click Chemistry.
There is a certain chemical reaction that is often referred to as the click reaction. But that’s a bit of a misnomer. Click chemistry is a framework or methodology for doing chemistry. Specifically, making complex organic molecules, mainly pharmaceutical ones.
A very short aside: the meaning of “organic” in organic chemistry is very different than its meaning in “organic food”. A food being labelled organic means it adheres to a set of guidelines that differ in each country, but generally are hypothetically better for the environment (but the same nutrition wise) and avoid using certain fertilizers and pesticides. Organic chemistry, meanwhile, just means that the molecules involved are made up almost entirely of carbon to carbon and carbon to hydrogen bonds, with some oxygen and nitrogen atoms thrown in for good measure.
With that out of the way, let’s take a look at the click chemistry sensation that has been sweeping the nations!
Just prior to the 21st century, K. Barry Sharpless got to thinking about the way we research new potential drug molecules. The most complex chemical structures weren’t made by chemists, they were made by nature. Far more often than not, researchers were inspired by an effect observed in nature. Chemists would then spend months or years trying to synthesize the same, compound that the plant, animal, or microorganism made nearly effortlessly.
For researchers, effortless it was not. To build a complicated chemical structure could take dozens and dozens of steps, each of which needed to be optimized, and which generated waste and by-products. It was time consuming, money consuming and energy consuming—both in the literal sense, as lab equipment can use a lot of electricity, and for the researchers. Purifying the desired product at each step was a pain, and a properly disposing of toxic waste generated during each step posed an environmental concern. Barry Sharpless wondered if there wasn’t a better way of approaching this challenge.
It was in 2001 when he realized that nature was the key, but not in the way we’d previously thought. Where other chemists tried to imitate nature, using scores of different highly specialized chemical reactions to perfectly mimic natural compounds, Sharpless took a different viewpoint. He observed that nature builds all of the molecules it needs out of around 35 carbon-based building blocks, none of which are really that complex. Nearly infinite compounds can be created from just a few relatively small molecules, just by linking them together with a nitrogen or oxygen atom. It’s how DNA is made, as well as sugars and proteins.
Sharpless argued for a minimalist, streamlined approach to synthesizing complex molecules, wherein only a handful of really good (i.e. high-yielding and widely applicable) reactions would be used. He envisioned using a small range of organic “building blocks” derived from petrochemicals joined together by these really good reactions, to synthesize large chemical structures that could function as drugs or have other purposes.
The Nobel committee likens it to the IKEA flatpack approach. Having built an apartment’s worth of IKEA furniture in the last week, I love this analogy. Basically, builders (chemists) are provided with all of the necessary furniture parts (the building blocks), along with simple to use hardware like Allen keys (the very good reactions), and instructions that are easy enough for anyone to follow to put it all together.
Barry Sharpless defined criteria for being considered one of these excellent reactions—which he named “click reactions”—since they worked so well that they essentially just clicked molecules together like Lego. To be considered part of click chemistry, a reaction needs a few characteristics:
Image Source: https://www.nobelprize.org/uploads/2022/10/fig2_ke_en_22_clickReaction.pdf
As I wrote above, there is one reaction that has become synonymous with click chemistry, to the point that it’s often referred to as simply “the click reaction”: the copper catalyzed azide-alkyne cycloaddition, or CuAAC (Cu is the periodic table shortform for copper). Barry Sharpless discovered it, but across the world in Denmark, at almost exactly the same time, so did Morten Meldal. Although Sharpless described its potential as enormous, neither researcher really knew that they were ushering in a new age of organic chemistry.
CuAAC quickly became the epitome of click chemistry. Before long it was it was the go-to for attaching nearly any two organic molecules together. Among many reasons it was so heavily embraced include how well it works, and the triazole linkage that it creates. Triazoles are quite stable, and are part of several important drugs, like fluconazole, a widely used antifungal medication. The CuAAC reaction sped up drug development tremendously and enabled all kinds of research that would have previously been very impractical, if not impossible.
However, there was one problem with the CuAAC reaction: its copper catalyst. Unfortunately, copper is highly toxic to living things. Some attempts were made to develop and include other compounds that could sequester the copper and prevent it from harming cells, but the next breakthrough came in 2004. This is where the third winner of the 2022 Nobel Prize in Chemistry comes in- Carolynn R. Bertozzi.
Wanting to study the complex sugars that sit on the surface of certain cells, Bertozzi was inspired by click chemistry’s simple and efficient nature. But, wanting to apply click chemistry to living cells meant finding a copper-free way of catalyzing the reaction. Looking back to the literature of 1961, she was inspired to use a ring-shaped molecule that was very unhappy being a ring.
Much like if you bend a pool noodle into a circle, molecules can often be bent into rings. But just like the pool noodle, they are clearly strained. The moment they’re given a chance, the molecule will spring open, just like the pool noodle when you let go. Bertozzi was able to harness that energy and create an incredibly powerful tool for studying molecular biology: the strain-promoted alkyne-azide cycloaddition,or SPAAC. With the toxic copper catalyst eliminated, researchers were off to the races! The applications for labelling and creating compounds that can be used in living cells or animals are numerous. I should know—it was absolutely integral to my M.Sc. thesis research!
We haven’t yet seen the full research impact of click chemistry, and we’ve already seen a lot. I have no doubt that Sharpless, Meldal and Bertozzi’s innovations will go down as defining moments in scientific history. Their impact on scientific research can’t be overstated, and therefore their potential to improve the lives of many. As the The Royal Swedish Academy of Sciences wrote, “In addition to being elegant, clever, novel and useful, it also brings the greatest benefit to humankind.”
This article was written for the McGill Office of Science and Society. View the original here: https://www.mcgill.ca/oss/article/medical-did-you-know/lesson-nature-what-click-chemistry-and-why-it-won-nobel-prize
Ada McVean 
