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LuxeSci Show Notes: S1E5: Gold

Hello again!  Welcome back to the LuxeSci Podcast, a podcast to re-ignite your wonder by exploring the intersection of science and luxury. I’m Dr. Lex, PhD, infectious disease expert, podcast host and, as i’ve said before, a lover of anything sparkly (this is going to be an ongoing theme). I had originally planned another topic for the second in my trilogy of holiday episodes but since it’s the end of 2021 and I’m hoping against hope that 2022 will be a little better, I thought we should do something big, something shiny, something that has epitomized luxury for millenia…gold.  Yellow gold cycles in and out of fashion but some version of gold is always part of how we adorn ourselves, whether it’s white gold, rose gold or yellow gold.  If you’re of the Christian persuasion, or spent enough time with the Christian nativity story, then you know that gold was one of the gifts that the Magi (Wise Men) brought to Jesus and even then it was associated with luxury (being a King).  So come along and join me for a very royal and scientific look at gold.


  • Background

  • Gold is an element with the symbol Au (from the Latin: aurum) and an atomic number of 79

  • Element - pure substance made up only of atoms with same number of protons in their nuclei (i.e. can’t be broken down further by any chemical reactions)

  • Atomic number - number of protons found in the nucleus of all the atoms of an element (gold - 79 protons).  Determines an element’s place on the periodic table of elements

  • In it’s natural state - gold is a reddish-yellow, dense, soft, malleable (can be hammered or rolled without changing its composition) and ductile (ability of a compound to be drawn into a wire)

  • Gold is extremely inert, (i.e. non-reactive), which is why my partner, who is an electrical engineer choose a gold wedding band, it wouldn’t conduct electricity if he shocked himself.

  • It’s a combination of these properties and gold’s resistance to acid and relative rarity that make it so in demand

  • So where does gold come from?  

  • So this is ridiculously fascinating to me.  Gold is thought to be generated in supernovas when they explode and from the collision of neutron stars and to be present in dust from which the Solar System is formed (isn’t that awesome in the original definition of that word)?

  • Scientists believe that most of the gold present in the early Earth would have sunk to the planetary core because Earth was molten so where did today’s gold come from?

  • Two main theories:

  • It was brought by asteroids during a phase of Earth’s history called the Late Heavy Bombardment (yikes)

  • Most notably - most of the gold that humans can mine is thought to have come from an asteroid that formed the Vredefort crater 2.020 billion years ago.  This crater is thought to have deposited gold in South AFrica, accounting for the richest gold deposits on earth

  • However - analysis of the rocks bearing the gold in this region were laid down 700-950 million years before the Vredofort impact so it wasn’t that asteroid

  • Also – these rocks were covered with a thick layer of lava before the meteor struck so the gold was already there and not alien in origin

  • The asteroid did make the gold-bearing rocks accessible though

  • Fun fact - it’s estimated that 22% of the gold existing on earth today has been extracted from these rocks in SA

  • Theory 2 - gold came to the surface from the deepest regions of the planet (the mantle), which seems the most likely for most of the gold on earth

  • Note - gold is a finite resources, not a renewable resource, fortunately, since it’s so malleable, it can be melted down and re-worked

  • A short history

  • Gold is probably the earliest recorded metal used by humans

  • Gold artifacts first appear in pre-dynastic Egypt and smelting gold goes as far back as the 4th millennium

  • The oldest known map of a gold mine was drawn in the 19th dynasty of ancient Egypt (1320-1200 BC)

  • There is a long, and often sordid history, of gold and gold mining that i don’t have time to cover here but i suggest you look it up

  • One last fun fact - oceans contain gold!  With an average of about 10-30 parts per quadrillion, the earth’s oceans are estimated to hold 15,000 tonnes of gold.  However, redeeming gold from the ocean has been elusive.

  • But just think - the next time you go for a dip in the sea, you’re taking the ultimate luxury bath

  • Cancer research

  • So gold isn’t just for making things look pretty.  There are potential medical applications for this element, primarily in the field of cancer diagnostics and treatment and as usual, i found a great review article about this topic by Singh et al published in the International Journal of Molecular Science in 2018

  • Recent advances in nanotechnology (manipulation of matter on a near-atomic scale to produce new structures, materials and devices)

  • Allowed for many elements to be used to make nanoparticles (a small particle that ranges between 1 to 100 nanometres in size) and nanomaterials (materials of which a single unit small sized between 1 and 100 nm.)

  • Gold nanoparticles possess unique characteristics that make them great for cancer diagnostics and treatment

  • Biocompatibility - won’t elicit too much of a reaction when injected into the body

  • Fluorescence - this shit glows!

  • Tunability - can easily change the size and shape of the particles (because gold is malleable)

  • Surface functionalization - can bind many different types of things to the surface of the particle

  • Synthesis of gold nanoparticles

  • Chemical - involves chemicals and solvents which may not be the best for humans or the environment and also involves extreme conditions which may be hard to replicate from batch to batch

  • Biological - medicinal plants can produce gold nanoparticles (through an extract of their leaves) and microorganisms can adsorb gold and then accumulate gold nanoparticles

  • Drug carriers

  • So what are these very luxurious nanoparticles use for?

  • One answer is the delivery of chemotherapeutic drugs

  • Traditional delivery methods (i.v, oral, etc) deliver the chemotherapy to the whole body, not targeted to the cancer cells.  This leads to only a fraction of the drug getting to the tumor site.

  • Also means side effects for other healthy tissues

  • Can load the drugs into or attached to the nanoparticles and those can be targeted for the tumor cell (by coating the nanoparticle with a tumor-specific antibody for example)

  • One drug, MTX (methotrexate used for some leukemias and non-hodgins lymphoma) showed high cytotoxicity (cell killing) of numerous tumor cell lines and accumulated fasters in the tumor cells

  • This research is still ongoing but shows promise in terms of better targeting the cancer cells

  • As of the writing of this review (2018) - there weren’t many gold nanoparticles approved by the FDA. one of the issues is around cytotoxicity.  While gold is relatively biocompatible, it’s ability to induce cell death is dependent on the size and shape of the nanoparticle. So stay tuned on this topic

  • Vaccines and adjuvants

  • We’ve been a lot about vaccines in the news these days (who’s got their booster?!) most vaccines also include an adjuvant 

  • Pause for a mini immunology lesson (sorry, can’t help myself) there are 3 words that start with the letter A that are important when talking about immunology

  • Antibody - blood protein produced in response to and counteracting a specific antigen. Antibodies combine chemically with substances which the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood

  • Antigen - a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies

  • Adjuvant - a substance which enhances the body's immune response to an antigen

  • Got it?  Great - back to the gold

  • Lev Dykman wrote a review for the Expert Reviews of Vaccines journal in 2020 looking at the literature published on using gold nanoparticles as adjuvants to optimize the performance of vaccines

  • Dr. Dykman found that gold nanoparticles has been used in research settings to prepare antibodies and vaccines against more 45 pathogens (germs)

  • Fun fact - the nanoparticles were shaped into nanospheres, nanocages, nanostars, nanocubes, nanoshells, nanoprisms and nanoclusters (remember, gold is malleable, right?)

  • Animal studies with gold nanoparticle adjuvants found increased response to the vaccine

  • There are several potential mechanisms for this amplification of the immune response including the ability of nanoparticles to more effectively deliver antigens to the lymph node (small particles are better at moving around the body), thus activating the antibody producing cells in the body and generating a more steady and gradual release of antibodies

  • Nanoparticles also concentrate the antigen on what are called antigen-presenting cells (cells that circulate in your body looking for foreign substances then eat it up and present on their cell walls for antibody-producing cells to see) - this enhances the proliferation and activation of cells that help antibody-producing cells (T cells) and the antibody-producing cells themselves (B cells)

  • While not gold nanoparticles, both Moderna and Pfizer mRNA COVID vaccines use lipid nanoparticles to deliver the vaccine antigens - pretty cool, huh?

  • Fun stuff

  • For some historical fun - in a paper published in 1988 in the Journal of the Royal Society of Medicine Dr. RM Hillson talked about the three gifts of the Magi, including gold

  • While we’re just beginning to see the impacts of gold nanoparticles on human health, the search for potable (drinkable) gold has been sought for centuries.  It was thought that potable gold would cure all known diseases and confer immortal youth

  • Alchemy (a form of speculative thought that, among other aims, tried to transform base metals such as lead or copper into silver or gold. It also sought to discover cures for diseases and a way of extending life.) was started by Jbir ibn Hayyan in the 6th century but he and his followers were not successful

  • Scientists didnt give up though.  In the 17th century, when the discipline of chemistry was becoming more defined, gold medicines were still very much en vogue

  • One method was to amalgamate the gold with mercury and make it into a powder - yep, that sounds super safe

  • Another concoction was called Saffron of gold and was made by pouring hydrocholoric acid, water and oil of tartar onto thin gold plates and drying on a paper by a fire but, gently, so it doesn’t explode!! It was said to cause sweat and drive out noxious Humors, to be given for smallpox and measles and to stop vomiting

  • There was a tincture of antimony and gold that was used to beautify some medicines to the eye and prevent nauseaousness - so toxic!!

  • In 1839 - gold was still used to promote secretions of the skin, salivary glands and kidneys and some forms of gold medicines were used to treat the secondary symptoms of syphilis, tumors, chronic skin diseases applied to ulcerations of the uterine cervix and the face (ouch!!)

  • By the end of the 19th century - gold compounds were not officially recognized in the UK but still used in Europe for tertiary syphilis, spinal sclerosis, uterine affections and gold bromide was used to treat hysteria and epilepsy

  • More recently in the 20th century, gold was used against TB. a sulphate of gold and sodium was first used in 1923 and weak solutions of gold inhibited the growth of the tubercule bacilli in culture.   And in 1930, gold salts were introduced as a treatment for rheumatoid arthritis

  • Today’s scientists join a very long history of trying to treat or prevent disease using gold, which as we’ve seen, has many unique and amazing properties and for now, i think i’ll keep to wearing gold jewelry

  • Glossary (lots of words today)

  • Element - pure substance made up only of atoms with same number of protons in their nuclei (i.e. can’t be broken down further by any chemical reactions)

  • Atomic number - number of protons found in the nucleus of all the atoms of an element.  Determines an element’s place on the periodic table of elements

  • Nanotechnology - manipulation of matter on a near-atomic scale to produce new structures, materials and devices)

  • Nanoparticle - a small particle that ranges between 1 to 100 nanometres in size


  • Antibody - blood protein produced in response to and counteracting a specific antigen. 

  • Antigen - a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies

  • Adjuvant - a substance which enhances the body's immune response to an antigen

  • Alchemy -  form of speculative thought that, among other aims, tried to transform base metals such as lead or copper into silver or gold. It also sought to discover cures for diseases and a way of extending life.


Thanks for listening to this episode of LuxeSci.  A very special thank you to my audio engineer, Dimos.  Our theme music is Harlequin Moon by Burdy. If you have a correction, comment or suggestion for a topic, you can reach me at: drlex@luxesci.com.  We’re on Twitter and Instagram at luxescipod and our website is luxesci.podcastpage.io.  If you like us, please subscribe.   Please also leave us a review where ever you listen to podcasts.  See you again in 2 weeks!




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