[HN Gopher] Dual antibacterial properties of copper-coated nanot...
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Dual antibacterial properties of copper-coated nanotextured
stainless steel
Author : westurner
Score : 90 points
Date : 2024-05-20 23:23 UTC (12 hours ago)
(HTM) web link (onlinelibrary.wiley.com)
(TXT) w3m dump (onlinelibrary.wiley.com)
| westurner wrote:
| "Dual Antibacterial Properties of Copper-Coated Nanotextured
| Stainless Steel" (2024)
| https://onlinelibrary.wiley.com/doi/10.1002/smll.202311546 :
|
| > Abstract: _Bacterial adhesion to stainless steel, an alloy
| commonly used in shared settings, numerous medical devices, and
| food and beverage sectors, can give rise to serious infections,
| ultimately leading to morbidity, mortality, and significant
| healthcare expenses. In this study, Cu-coated nanotextured
| stainless steel (nSS) fabrication have been demonstrated using
| electrochemical technique and its potential as an antibiotic-free
| biocidal surface against Gram-positive and negative bacteria. As
| nanotexture and Cu combine for dual methods of killing, this
| material should not contribute to drug-resistant bacteria as
| antibiotic use does. This approach involves applying a Cu coating
| on nanotextured stainless steel, resulting in an antibacterial
| activity within 30 min. Comprehensive characterization of the
| surface revealing that the Cu coating consists of metallic Cu and
| oxidized states (Cu2+ and Cu+), has been performed by this study.
| Cu-coated nSS induces a remarkable reduction of 97% in Gram-
| negative Escherichia coli and 99% Gram-positive Staphylococcus
| epidermidis bacteria. This material has potential to be used to
| create effective, scalable, and sustainable solutions to prevent
| bacterial infections caused by surface contamination without
| contributing to antibiotic resistance._
|
| - "This modified stainless steel could kill bacteria without
| antibiotics or chemicals" (2024)
| https://phys.org/news/2024-05-stainless-steel-bacteria-antib...
| westurner wrote:
| "Scientists create virucidal silicon surface without any
| chemicals" (2023)
| https://news.ycombinator.com/item?id=39196781#39196822 :
|
| "Piercing of the Human Parainfluenza Virus by Nanostructured
| Surfaces" (2024)
| https://pubs.acs.org/doi/10.1021/acsnano.3c07099 :
|
| > _We used reactive ion etching to fabricate silicon (Si)
| surfaces featuring an array of sharp nanospikes with an
| approximate tip diameter of 2 nm and a height of 290 nm. The
| nanospike surfaces exhibited a 1.5 log reduction in infectivity
| of human parainfluenza virus type 3 (hPIV-3) after 6 h, a
| substantially enhanced efficiency, compared to that of smooth
| Si._
| ceejayoz wrote:
| What happens if you breathe the coating in?
| westurner wrote:
| Copper toxicity > Signs and symptoms:
| https://en.wikipedia.org/wiki/Copper_toxicity#Signs_and_symp...
| :
|
| > _The US EPA lists copper as a micronutrient and a toxin. [11]
| Toxicity in mammals includes a wide range of animals and
| effects such as liver cirrhosis, necrosis in kidneys and the
| brain, gastrointestinal distress, lesions, low blood pressure,
| and fetal mortality. [12][13][14] The Occupational Safety and
| Health Administration (OSHA) has set a limit of 0.1 mg /m3 for
| copper fumes (vapor generated from heating copper) and 1 mg/m3
| for copper dusts (fine metallic copper particles) and mists
| (aerosol of soluble copper) in workroom air during an eight-
| hour work shift, 40-hour work week. [15] Toxicity to other
| species of plants and animals is noted to varying levels. [11]_
|
| A reasonable production process would need to contain and could
| probably reuse copper emissions
| greenavocado wrote:
| If you ever spend time within a few hundred meters of other
| cars such as while driving around or walking along a road you
| are inhaling large amounts of aerosolized metal particles from
| brake dust. If you want a large sample to verify this
| phenomenon, pull up to a semi tractor trailer as the truck
| brakes to a sudden stop such as when slowing down on the
| freeway upon hitting heavy traffic and take a good whiff.
| ceejayoz wrote:
| Are they specifically _engineered_ to be deadly to cells,
| though?
| callalex wrote:
| Can you explain the relevance of this question? I think
| it's likely I'm missing something, but your question sounds
| like: "Yes, volcano eruptions have killed innumerable
| people and species...but were they _specifically
| engineered_ as killing machines?? Gotcha!"
| serf wrote:
| here's the relevance :
|
| a bow and arrow and a gun both shoot projectiles. One of
| them has more regulation due to improved efficacy at
| shooting projectiles.
|
| The presumption here would be that the materials designed
| for killing cells would do so in a drastically better
| fashion than materials that are designed for better brake
| performance but which also coincidentally shed harmful
| particles.
|
| Using your concept : it would raise questions if we heard
| about a human-lead effort to develop the most cataclysmic
| volcano eruption ever produced.
|
| I didn't get the premise that it's supposed to be a
| gotcha; it's not. It's just a different thing. We gain
| benefit from better brakes, it's not all loss.
| Aloisius wrote:
| Engineered? It's metallic copper.
| ceejayoz wrote:
| And "nanotextured stainless steel"?
|
| Asbestos is just... rock.
| Aloisius wrote:
| Yes. They etched stainless steel.
|
| I'm not seeing the comparison to asbestos which is
| dangerous regardless of form.
| ceejayoz wrote:
| Asbestos is dangerous _because_ of its form. It isn't
| inherently toxic, it just pokes your lung tissues to
| death.
|
| This is why I find a new material with "nanoprotrusions
| measuring 20-30 nm" in an article talking about
| "nanodaggers" killing cells somewhat concerning.
| thsksbd wrote:
| Specifically SiO2 which does not dissolve
| numpad0 wrote:
| Is rock safe?
| actionfromafar wrote:
| Against scissors, yes.
| thsksbd wrote:
| But at these length scales these materials are very
| corrodable, even stainless steel. They wont last long in
| the body.
|
| Unlike, say, textures silica that was on here a few months
| ago. Then I raised this exact concern since SiO2 wont just
| disappear.
| westurner wrote:
| How much longer do brake pads on trucks with regenerative
| braking last?
|
| Though, wouldn't a differently shaped initial acceleration
| torque curve save synthetic tire microplastics from the
| ocean, while we figure out how to make dandelion rubber
| tires?
| hinkley wrote:
| Last time I went in the dude mentioned offhand that my
| current model of brake pads wouldn't be for sale by the time
| I needed new pads because mine were sintered (with?) copper.
|
| Might be state by state but sounds like it's on people's
| radar at least.
| BenFranklin100 wrote:
| As an aside, an argument in favor of mass transit vs electric
| cars, is that EVs do nothing to reduce particulate matter
| pollution from tires and breaks.
| DarmokJalad1701 wrote:
| > is that EVs do nothing to reduce particulate matter
| pollution from tires and breaks
|
| Except for not using brakes for the most part. EV brakes
| typically last for the life of the car.
|
| https://en.wikipedia.org/wiki/Regenerative_braking
| BenFranklin100 wrote:
| And your tires?
| InitialLastName wrote:
| Your quote:
|
| > EVs do nothing to reduce particulate matter pollution
| from tires and breaks.
|
| "Substantially reduce particulate matter pollution from
| brakes" sounds like doing "something", not "nothing", to
| me.
| BenFranklin100 wrote:
| Which is why I used a logical conjunction.
|
| https://www.oecd-ilibrary.org/sites/4a4dc6ca-
| en/1/3/3/index....
| coldtea wrote:
| If one thought EVs did something help with one of the
| two, they'd have omitted it from the list of things "EVs
| do nothing" to help with.
|
| Something that helps with X cannot be said to do nothing
| to help with "the problem of X and Y". If they reduce it
| for tires, then they do reduce the problem of
| "particulate matter pollution from tires and breaks" -
| proportionally to how much the latter contributes to said
| problem.
| abakker wrote:
| Well, you were the one who grouped them. The reality is
| that EVs wear tires equivalently fast to other similar
| weight vehicles and wear brakes very very slowly. And
| reduce carbon emissions. And noise.
| BenFranklin100 wrote:
| I grouped them together,because overall EVs appear to
| have marginally less non-exhaust particulate matter
| pollution than gas vehicles:
|
| https://www.oecd-ilibrary.org/sites/4a4dc6ca-
| en/1/3/3/index....
|
| In other words, the road to a mostly pollution free
| transit future will be laid with tracks rather than
| asphalt.
| bdamm wrote:
| It will be laid by first understanding reality, which
| includes the enormous road network we have today and the
| social motivations to expand it. Just bleating about how
| great it would be if everyone used transit isn't going to
| change a damn thing.
|
| EVs are a solid and realistic step towards reducing our
| worst pollution problems. Widely available car sharing
| and autonomous vehicles would be a great solution to the
| last mile and even reducing the problem of so much space
| being used for parking, while improving the walkability
| of our cities. Look towards possibilities that can work,
| instead of clinging to models that can't address the
| problems of today.
| geraldwhen wrote:
| Never in America. We live too spread out, and many cities
| lack coherent work centers.
| rickydroll wrote:
| Thanks to regenerative braking, my brake disks rust long
| before they wear out. Tire particulates are an engineering
| problem that will be solved long before the social problem
| of convincing people to live close enough to make public
| transit practical.
| BenFranklin100 wrote:
| And your tires?
| greenavocado wrote:
| I'm never going to take public transit in the United
| States if I can help it because there are too many
| unhinged psycopaths and it takes just one. When I visit
| Europe it's all I take day in day out. Except certain
| parts of Paris and the UK which have had lots of recent
| arrivals. But even the new arrivals are less insane than
| many of the characters found on US public transit.
| bragr wrote:
| As opposed to in traffic? Plenty of road raging psychos
| out driving cars.
| Hextinium wrote:
| The conclusion is that the US just has more psychos. But
| the restraint of wrecking their vehicle to accost me
| holds them in line. On public transit they can accost me
| and nothing stops them.
| InitialLastName wrote:
| Unless there's a ramification of electromagnetism that I'm
| missing, cars that do the bulk of their braking through
| regeneration require their conventional brakes to absorb
| far less energy, reducing the particulate matter generated.
| rnewme wrote:
| However they're much much heavier, generating more tire
| and brake dust.
| galangalalgol wrote:
| And unless the mass transit is tireless, it will be even
| heavier. Tire wear and this microplastics go up with the
| square of axle weight, so individual transportation is
| actually better from that standpoint.
| urban_winter wrote:
| But mass transit carries more people per wheel, and the
| weight of the bus does not scale linearly with the
| carrying capacity, so it doesn't automatically follow
| that "individual transportation is actually better...". I
| doubt that 50 EVs carrying one person each generate less
| tyre wear than one bus carrying 50 people.
| XorNot wrote:
| Road damage is a function of the power of 4[1] generally.
|
| A BYD bus weighs 18 tons and carries 32 people including
| the driver. [2]
|
| A BYD Atto 3[3] carries upto 5 people and weighs 1.8 tons
| unloaded.
|
| The proportional road wear function of the BYD Atto would
| be about 10 (1.8^4). For the bus it would be (18^4)
| 104,976.
|
| So the bus is 10,000 times more wear then the car. Per
| passenger it's 3000 wear units for the bus versus ~10 for
| the car.
|
| [1] https://en.m.wikipedia.org/wiki/Fourth_power_law
|
| [2] https://en.m.wikipedia.org/wiki/BYD_K_series
|
| [3] https://ev-database.org/car/1782/BYD-ATTO-3
| LargoLasskhyfv wrote:
| Roads are for walking, bicycling and
| repair/cleaning/utility/emergency services. Deliveries go
| by subterran pallet-delvicery networks, to be last-miled
| by freight-cycles. Mass-transit by rails. Long-transit by
| maglev or air.
|
| Fuck cars!
| adrianN wrote:
| The average car carries 1.2 people, how many does the
| average bus carry?
| silver_silver wrote:
| I did some research and it seems this is already a
| problem with ICE vehicles because of the pickup/SUV
| trend.
|
| I don't know how precise this data is, but apparently the
| top selling models in the US are [1]:
|
| 1. Ford F-150 (1,846-2,584 kg)
|
| 2. Chevrolet Silverado (2,029-2,272 kg)
|
| 3. Toyota RAV4 (1,530-1,640 kg)
|
| 4. _Tesla Model Y_ (1,884-1,998 kg)
|
| 5. Honda CR-V (1,500-1,681 kg)
|
| 6. Dodge Ram (2,176-3,418 kg)
|
| 7. GMC Sierra (2,029-2,272 kg)
|
| 8. Toyota Camry (1,480-1,660 kg)
|
| 9. Toyota Tacoma (2,007-2,032 kg)
|
| 10. _Tesla Model 3_ (1,611-1,836 kg)
|
| They do seem to average 200-300 kg more than a comparable
| ICE model but as a whole they're not tremendous outliers.
|
| [1]: https://www.edmunds.com/most-popular-cars/
| infogulch wrote:
| Regenerative braking means that if you drive them right EVs
| can have factory brake pads at 100k+ miles that look new.
| https://x.com/niccruzpatane/status/1785043593427640326
| ZeroGravitas wrote:
| This also allows for use of drum brakes, which have rare
| issues of overheating when used alone but are fine with
| regen doing most of the work. Those contain the abrasion
| materials within themselves.
|
| Some EVs already use them but to become common it'll
| probably require new regulations like the EU is planning
| to overcome the "ugh factor" because they used to be the
| cheap, low end options.
| xyzzy_plugh wrote:
| In what scenario would you be exposed to the aerosolized
| coating, assuming it is aerosolized at all?
| callalex wrote:
| The history of ewaste recycling is horrifying and is worth
| thinking about before making more in the future. And I'm
| using ewaste as the friendly term for hazmat/hazardous
| materials. All too often they end up in a huge burn pile that
| uneducated impoverished children set on fire and then climb
| and forage in.
| ceejayoz wrote:
| Same scenarios I'm exposed to Teflon; widespread use
| everywhere long before we know the safety profile. If it's
| effective, folks are going to want it in hospitals, school
| buses, hand railings at public places, elevator buttons, the
| works.
|
| It took decades for the risks of PFAS materials to properly
| surface.
| Aloisius wrote:
| Copper has a very long safety record. Comparing it to PFAS
| is ridiculous.
| ceejayoz wrote:
| I'm more wondering about the nanotextured steel.
| thsksbd wrote:
| You're right to be concerned. Material innovators should
| be open about these things.
|
| Copper is toxic, but at these levels shouldnt be a
| concern.
|
| Nano stuff are nasty, but since copper in the body cannot
| last long (corrosive environment), the nano particles
| will quickly disappear.
|
| This is likely to be far more benign than other nano
| materials.
|
| The question is, will this survive outside a lab?
| dylan604 wrote:
| It depends on what's being compared. Anything that has a
| known negative effect that is intentionally suppressed in
| order to maximize profits all fall into the same category
| to me regardless of that the "it" actually is. At the
| same time, we have plenty of historical evidence where a
| new thing was thought to be the greatest thing since
| sliced bread and rushed to market only to be found that
| it is pretty nasty stuff. We can now test the new thing
| much more rigorously if only someone wants to spend the
| money and possible delay in profits which is no company
| ever.
| numpad0 wrote:
| Copper is not safe, which is kind of the point.
| DannyBee wrote:
| That safety record says that copper dust/particles are
| _definitely_ toxic to humans and there are plenty of
| instances of it getting into things it should not so I 'm
| not sure what you are trying to say.
|
| If copper found its way into everything as invidiously as
| pfas has, that would be really bad
| refurb wrote:
| Teflon - poly(tetrafluoroethylene), is used in medical
| implants in the human body.
|
| I wouldn't about it.
|
| PFAS? That's different.
| duffpkg wrote:
| As someone that has built and operated large multipractice and
| acute care facilities some of the most vicious fights I've had
| with medical entities and boards is about changing hardware back
| to the older brass/copper which is inherently antibacterial and
| only needs cleaning with soap/water to self disinfect versus
| stainless steel which needs cleaning with bleach and can foster
| or even lead to the creation of resistant and other problematic
| bacteria. The objections were mostly about the visual appearance.
| I am not sure I see the advantage to this new material over the
| good old brass/copper. There is a perceived cost premium to it
| but it isn't meaningful in practice. This paper alleges this new
| process is cheaper but I would be incredibly dubious of that. At
| ClearHealth we were successful in substantially reducing hospital
| acquired infection (HAI) rates at managed facilities to industry
| best in part because of our "reversion" to copper/brass hardware.
|
| One of the most obvious signs you are in a well managed health
| system is seeing copper/brassy touch surfaces instead of
| stainless.
|
| https://www.copper.org/publications/newsletters/ba-news/2010...
| https://en.wikipedia.org/wiki/Antimicrobial_properties_of_co...
| https://www.statnews.com/2020/09/24/as-hospitals-look-to-pre...
| koolba wrote:
| From the Wikipedia page:
|
| > The oligodynamic effect was discovered in 1893 as a toxic
| effect of metal ions on living cells, algae, molds, spores,
| fungi, viruses, prokaryotic, and eukaryotic microorganisms,
| even in relatively low concentrations.[7] This antimicrobial
| effect is shown by ions of copper as well as mercury, silver,
| iron, lead, zinc, bismuth, gold, and aluminium.
|
| So I can justify wearing a bunch of oversized gold chains as
| "for my health"?
| nelox wrote:
| Go the whole-hog and dip yourself in mercury.
| westurner wrote:
| Do the useful properties of copper change with oxidation?
|
| Silver is also antimicrobial, and also expensive.
|
| FWIU nanospikes in silicon achieved virucidal outcomes in small
| trials as well.
|
| Is copper virucidal without nanospikes?
|
| (On this topic, Hemp textiles are antimicrobial / bactericidal:
| https://news.ycombinator.com/item?id=39196781#39197019 )
|
| "Scientists create virucidal silicon surface without any
| chemicals" https://pubs.acs.org/doi/10.1021/acsnano.3c07099
| https://news.ycombinator.com/item?id=39196822
| duffpkg wrote:
| Oxidation is a problem as is physical debris but touch
| surfaces are cleaned at least daily in a hospital setting
| anyway. Plain old Copper/brass that has been used since
| forever is virucidal without any special treatment.
| jahewson wrote:
| A frequently touched surface isn't going to have a problem
| with oxidation:
|
| https://en.m.wikipedia.org/wiki/Statue_rubbing
| aitchnyu wrote:
| So the people rubbing breasts of statues to a shine were
| doing it for uh... serious reasons?
| technofiend wrote:
| Nosocomial infections are terrifying because they're often
| things that have as you said survived in a very harsh
| environment. Thank you for doing your part to reduce them.
| jahewson wrote:
| Set up a company selling remarkably over-priced "medical" door
| handles and healthcare providers will fall over themselves to
| buy them.
| DannyBee wrote:
| Copper is of course, chemically incompatible with most
| disinfectants and cleaners and will corrode. Which is one
| reason it stopped being used when ammonia/etc became super
| common. They are less common now in straight form (even Windex
| is no longer mainly ammonia unless you use the original formula
| version)
|
| So solid copper/brass i can get behind because it probably
| doesn't affect lifetime meaningfully, but I am very curious how
| the coating in the article withstands splashes of ammonia or
| peroxides or other things used to clean the floors or windows.
| FieryTransition wrote:
| I was wondering about this too, it's not viable to have a
| coating which necessitates changing equipment periodically.
| It will add logistical problems and waste. I think you are
| right in that using solid metals instead, makes more sense,
| given antibacterial properties have been known to exist for
| these for a while. The question is if all types of pathogens
| can be removed without damaging the equipment, or if material
| research could create an alloy which just like stainless
| steel, could make the metal form an oxidation layer which
| would protect it in case of contact with corrosive liquids.
| garyclarke27 wrote:
| Wood also has excellent antimicrobial properties e.g. makes a
| much safer cutting board than plastic
| Traubenfuchs wrote:
| ...but you can easier wash plastic in the dishwasher, while
| wooden cutting boards get warped and destroyed.
| jschveibinz wrote:
| 50-75 years ago, brass handles were the norm on public buildings
| like schools, government buildings, factory buildings, hospitals,
| etc.
|
| Can we please stop changing things that don't need to be changed?
| BartjeD wrote:
| Copper gets stolen a lot these days. Even from cables. So door
| handles might not be the best idea.
| RF_Savage wrote:
| Brass handrails and large door handles do regularly get
| stolen here.
| hoseja wrote:
| The solution is to punish and prevent theft, not to give up.
| coldtea wrote:
| Both of those are hopeless as the US crime stats show
| despite the medieval punishment system.
|
| It's more about preventing the root cause of crime: culture
| and economy.
| sirwitti wrote:
| Which unfortunately is not a solution since harsher
| punishments have shown to not prevent crime.
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