How do microneedles deliver drugs? HD


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.

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