This a scale model of our micro needles.
Obviously this is made out of plaster cast
and is about 6 centimetres high normally a
micro needle could be 600 micrometres high
just greater than half a millimeter in height
and instead of being made from plaster cast
it's made from a hydrogel forming material.
So this is essentially a similar material
to what soft contact lens are made from so
it is hard in the dry state, can penetrate
the skin but it rapidly then takes in fluid
from the viable skin and swells to form a
more jelly like material and it's through
this jelly that we can either deliver medicines
or pick up bio markers and medicines that
are already in the person body from monitoring
purposes and if we insert these into a person's
skin it feels like a cat's tongue or a little
piece of Velcro or an emery board.
There is no pain and no bleeding.
If we consider first of all the advantages
of micro needles as compared to a conventional
hypodermic syringe then we have the minimally
invasive nature of the micro needles so we
are no longer now having a device that will
cause pain and potentially bleeding and could
actually be stuck into another person either
on purpose or by accident so we don't have
the issue of disposal that we would have with
a conventional needle and syringe.
If we think of micro needles as an alternative
to conventional oral administration of medicine
from tablets to capsules we now have the opportunity
to improve the bio availability of macro molecules
like peptides and proteins but also to control
the administration of a whole range of drugs
over several days and this could be particularly
important in elderly patients for examples
who are on numerous medicines and often struggle
to remember to take their tablets.
Video shows the microneedles under an electronic
microscope, then a print at much higher magnification
showing an unused and used microneedle.
Then he shows more images of the microneedles
piercing the skin when in use, again, at very
high magnification
It is vitally important that we are able to
visualise micro needles because clearly our
eye cannot see them they are on such a small
scale.
In this first image we see a light micro graph
of our micro needles that are gold coated
prior to scanning electronic microscopy imaging
and we can see the individual micro structures
and the base plate upon which they are formed.
Our next image shows a scanning electron micrograph
of a single micro needle penetrating through
the stratum corneum which is the outer most
barrier layer of our skin and once our micro
needles are in the skin they will rapidly
take up skin interstitial fluid to form these
discrete hydrogel bulbs and that is what we
see in our next image.
So even though our micro needles become soft
when inserted into skin through the uptake
of fluid what we can see here is a micro needle
that has been removed from the skin and this
indicates that we can remove the micro needles
completely intact and we do not deposit any
polymeric material behind in the skin and
this is what our final two images show so
these are the micro needles inserted into
the skin of my former phd student Martin Garland
in our final image then we see a 3D rendered
image of the entire array of 361 micro needles
inserted into Martin's skin so we can study
the depth of insertion of every single micro
needle and this will be important as we follow
up and try to develop methods of patient application
that are reliable and can be done in the same
way by every patient every time.
