| Silicone is used as a coating on
needles enabling a smooth, comfortable puncture
Commonly known for their use in the pharmaceutical and vitamin
industry, researchers are looking into new niche uses for
industrial minerals, such as helping in the fight against
cancer, or prevention against Alzheimers disease. As
surgeons and medical companies move away from metal to plastic
implants, the role of minerals grows in surgical applications
Though the medical industry will
unlikely be the main driver behind production, the importance
of minerals in medicine is undeniable as a niche and developing
use for pure, high-grade minerals.
Lithium carbonate tablets have been
used as a medication to treat a number of mental health issues
including depression, mania and bipolar disorder, working to
affect the levels and activity of certain chemicals in the
Evidence has indicated that lithium
may also be used to prevent Alzheimers disease, a
progressive mental deterioration occurring in middle or old
age, due to generalised degeneration of the brain.
A report published by Nunes et
al in 2007, Lithium and risk for Alzheimers
disease in elderly patients with bipolar disorder,
outlined that the prevalence of Alzheimers was
significantly less in a group of elderly patients with bipolar
disorder on continuous lithium treatment than in a similar
group without lithium therapy.
The report discussed whether there
is a possibility of lithium having a preventative effect
against Alzheimers disease and if it might potentially
prevent the disease through a prophylactic effect on mood
According to the study, the rate of
dementia increased by 13% with every depressive disorder
episode, and 6% for those with bipolar disorder. If lithium
reduces the number of episodes, it might potentially be able to
prevent dementia in this way.
Taking lithium also inhibits
glycogen synthase kinase 3 (GSK-3) alpha and GSK-3 beta in the
brain, another potential avenue which may contribute to the
prevention of Alzheimers disease.
Dr E B Ilgren, consultant scientist
and physician formally of the University of Oxford, spoke to
IM about the possibility of lithium being used
as a preventative treatment for Alzheimers disease.
He noted that although some
evidence indicates using lithium would be advantageous, so far
no preventative studies have been carried out specifically for
Ilgrens joint paper,
Environmental Lithium Exposure in the North of Chile
outlines that: We still know almost nothing about the
effects of lithium on normal people particularly in terms of
brain function, and states that the risks of high doses
of lithium must still be explored.
Four main issues relevant to the
human risk assessment for lithium need to be addressed; the
effects of lithium on reproduction; its effects on human
development; repeated dose toxicity; and exposure related
observations in humans.
Ilgren outlines that so far any
trials to explore effects on development and reproductive
toxicology have only been carried out on animals, which have no
human relevance, while exposure related observations in humans
have been limited, and existing data is not sufficient for
The way forward then, Ilgren said,
is to finish characterising the population in the north of
Chile, which was historically heavily lithium loaded with no
outward signs of lithium toxicity. These populations were
studied forty years ago as part of a broader study, meaning
that the names of participants and their historical lithium
concentrations are still available for study today.
[We need to] examine them for
evidence of individual and population based effects
attributable to the long term, low dose environmental exposure
demonstrating manifestations strongly suggestive of effects
that would be due to lithium and its ability to reduce brain
degeneration clinically, radiologically and
pathologically, Ilgren told IM.
Population characterisation is
already underway, and Ilgren hopes that if enough funding comes
through, it can be completed in the next two years.
The next step then would be
to identify periods of exposure critical to these attributable
effects so one would know when to start preventative treatment
and for how long, he added.
Ilgren hopes that if clear evidence
can be demonstrated that lithium is neuroprotective and helps
to prevent the development of Alzheimers disease, it can
start being used as a treatment in the next five to 10
However he stressed that the
treatment is not a certainty and that more research and trials
are certainly needed before this small but important niche use
for high grade lithium can be implemented.
Silicone is a durable synthetic
polymer of silicon with carbon and oxygen that can be in a
solid, liquid or gel form. It has numerous medical uses, such
as in antacids, contact lenses, artificial joints, pacemakers
and cosmetic implants. It is also used in polishes and
lubricants, and for less obvious applications like equipment
In August 2012, silicone technology
company NuSil published a paper on the advantages of coating
needles with six different coatings to relieve their
penetration and drag forces.
The study compared penetration
forces of both coated and uncoated needles to compare the
effectiveness of the companys needle coating materials in
lowering the force needed to penetrate and pass through a
Hypodermic needles generally have
rough surfaces which cause friction, resulting in a certain
level of damage to the skin and causing discomfort for
Although the shape of needles
themselves - tri-bevelled, meaning they have sloping edges,
with an elliptical opening and an elongated tube - eases
penetration, the metal itself still causes friction, which
according to NuSils paper prevents a smooth, comfortable
MED-6613-2, the companys
silica-reinforced pigmented cured silicone elastomer was found
to be the most effective coating in providing lubrication
effects for needles, although coating the needles used for the
study with any of the silica sample materials resulted in
significantly lower drag forces than the uncoated control
Nuclear protection and
The Tohoku 9.0 magnitude earthquake
and resulting tsunami that struck Japan on 11 March 2011 was
one of the most devastating events in the countrys
history, claiming over 15,000 lives and causing a nuclear
disaster which sparked panic buying of potassium iodide (KI)
The Center for Disease Control and
Prevention (CDC) explains that KI tablets are stable iodine in
a medical form, which is needed by the body to make thyroid
hormones, though most KI intake comes from the food we eat.
In the case of a nuclear disaster
like that in Japan, radioactive iodine is released into the air
where it can be breathed in, or it can contaminate the local
food or drink supply through which it can cause internal
contamination if ingested.
Radioactive iodine absorbed by the
thyroid can injure the gland, but taking KI tablets will cause
the gland to absorb stable iodine instead, blocking the gland
from absorbing any more iodine - radioactive or otherwise - for
around 24 hours.
KI tablets however only work to
protect the thyroid - they do not protect the rest of the body
and cannot reverse damage already caused by radioactive
According to the CDC Guideline for
Disinfection and Sterilization in Healthcare
Facilities published in 2008, Iodine solutions can also be
used as an antiseptic before a procedure, while iodophors, a
combination of iodine and solubilising agent carrier, have been
used as both antiseptics and disinfectants.
The guideline points to several
reports which have documented that an iodophor demonstrates a
faster bactericidal activity than a full strength iodine
solution, although the reasoning behind this is unclear. The
solutions work by penetrating cell walls of microorganisms
quickly, causing a lethal effect by disrupting protein, nucleic
acid structure and synthesis in a cell, thus killing the
Another use for iodine in medicine
is during certain types of x-rays used to diagnose urinary
X-ray beams, which produce images
of the bodys internal structure, are absorbed in varying
amounts depending on the density of the material being X-rayed.
Bone for example shows up as white, while air in a
persons lungs would appear black.
During an intravenous urogram
(IVU), a contrast medium is necessary to provide more detail on
an X-ray image. In such cases iodine solution is usually
injected into the veins, which then moves to the bladder and
kidney, allowing for greater detail on the subsequent X-ray
Bone substitution and
Hydroxyapatite (HA), is a naturally
occurring mineral form of calcium and phosphorous with similar
properties to the mineral element in human bones, and it is
because of this similarity that it is often used as a coating
for medical implants.
Biomedical coatings provider APS
Materials Inc. is a provider of HA coatings for medical devices
such as hip and knee replacements and dental implants, allowing
for cement-less implants, promoting osseointegration between
the bone and orthopaedic implants.
According to the company, one of
the issues of cemented implants is that they can loosen over
time, potentially generating wear debris, which can trigger an
immune response in the human body as it is recognised as a
Many reports suggest that HA
coatings precipitate faster bone fixation and a reduction of
pain and recovery time for implant patients, says
As time passes, dental and
orthopaedic implants coated with HA show a greater success rate
in terms of the overall function of the implant. HA coatings
(É) are unique in that they are capable of connecting
structurally and functionally with human bone, the
HA and other calcium mixtures can
also be injected or applied manually for use as bone substitute
for voids or gaps in the skeletal system caused by previous
surgery or trauma, for example in extremities, craniofacial,
the spine and pelvis.
Part of the kaolin family,
halloysite is a rare clay which has contributed to medical
research as it has been used to target circulating tumour cells
in the body.
Cancer metastasis is when a tumour
spreads to different parts of the body via circulating tumour
cells which are released into the bloodstream and flow to
another part of the body where they stick to a surface (such as
organs). Halloysite could provide the key to detection and
eventual manipulation of these cancer cells.
We have been developing some
procedures to try and isolate and detect tumour cells in the
blood stream, Michael R. King, associate professor of
biomedical engineering at Cornell University, US, told
The detection of circulating cancer
cells is difficult given their tiny proportion in a millilitre
of blood in comparison to millions of white blood cells and
billions of red blood cells, but they can be detected by
creating surfaces that mimic the interior surface of blood
cells which cancer cells adhere to in the body. The adhesion
does not come from halloysite but instead from a group of
proteins called selectins.
Halloysites benefit lies in
that a layer of it applied to the created surface basically
repels the numerous white blood cells that accumulate as the
bodys immune system activates. In doing this, it greatly
increases the purity of tumour cells in the sample and as such
means that circulating tumour cells can be targeted with
While this is not strictly a cancer
cure, it would prevent the cancer from metastasising around the
body and forming new cancers.
As halloysite does not allow the
accumulation of white blood cells it could be used as
biomaterial, having the potential of preventing the immune
system from attacking the foreign body with a wide range of
applications in the medical industry, including in preventing
the body attacking implants.
Though some minerals, such as
lithium to treat bipolar disorders and magnesia for an upset
stomach, are used as a treatment, others function as a carrier
for medicine in tablets, pills and syrups.
Talc, calcium carbonate, phosphate
and kaolin all appear in medicines as a carrier or as a
Overall, high value minerals
inÊpharmaceuticals and medical applications are never
going to be the big business drivers for the worlds
largest miners due to their speciality applications and low
However, as new uses are explored and the medical industry
evolves, minerals are being used in increasingly varied
applications, offering for many producers a significant bonus
if the company can provide a high quality product.