Venegas, Urian
WRIT340
Professor Ramsey
April 29 2013
Jet Injections: The Lorentz-force Actuator
A Brief History:
It is that time again; time to see the dreaded doctor. Fear takes over and the mind is
flooded with a million plans on how to best avoid the doc. You pare frightened by
knowledge that within a couple of hours, some stranger will be puncturing the delicate
surface of your skin with a few centimeters of cold, glossy metal in an attempt to vaccinate
you. However, this vaccine is a necessary evil and carries the potential to save millions of
lives, including your own. You pause, you remember. Hypodermic needles are a thing of
the past, recently replaced by painless Jet injections capable of inserting powder or liquid
medicine directly into your veins, eyes, or tympanic membrane.
Centuries of trial and error have molded a wide array of drug delivery
systems ranging from pills and oral ingestion to rapid methods like direct blood stream
injections via needles [1]. The latter, has dominated quick delivery systems due to its rapid
and cheap nature. As a result, improving direct blood stream delivery methods have
acquired millions for research resulting in its next metamorphosis: Jet Injections. Jet
injections are currently available in the market and continue to grow in use. As of now, two
main types remain dominant; gas powered jet injections and spring loaded jet injections.
They carry the ability to insert liquid and powder forms of medicine and prevail over
traditional hypodermic needles in every conceivable way, except for direct cost.
How does the Lorentz-force actuator work:
Recently, The Massachusetts Institute of Technology has publicly released the
next evolution of jet injection in the form of a Lorentz-force actuator. The Lorentz-force
jet injector, shown in Fig. 1, functions as a highly controllable, needleless injector with the
capacity to instill both liquids and solids (in powdered form) into the skin, eye, or even
tympanic membrane. [2]
Figure1: A 3-D model of the Lorentz-force actuator. Source: [2]
This jet injector is revolutionary because it is neither gas nor spring powered but rather, as
the name suggests, it is powered through the Lorentz-force: an electromagnetic force. As
seen in Fig. 1 the device consists of a magnet in the middle surrounded by a coil of
conductive wire with a piston positioned in the protruding ampoule. When a controllable
current is applied to the system, a Lorentz-force is created resulting in the piston either
moving out of, or into the system [2]. The piston, in turn, pushes drugs of either powdered
or liquid form into or out of the desired location. The beauty of the system lies with the
electromagnetic properties used to operate the jet injector. When current is applied in a
one direction, a magnetic field is induced pushing the piston outward. Induce a current in
the opposite direction, and the piston retracts. Furthermore, the speed at which the piston
shoots out and retracts is dependent on the magnitude of the applied current [3]. As a
result, one can inject a substance near the speed of sound, about 340 m/s, with an applied
pressure of 100 megapascals, in about one millisecond [2]. The drug is then painlessly
injected into a desired location out of an ampoule roughly the diameter of a mosquito
proboscis. Since current drives the device, and current can be controlled over miniscule
amounts of time, the Lorentz-force actuator can change the speed at which it injects a drug,
while it is still injecting it, an attribute not held by existing injectors of any kind. This allows
for the drug to be spread over a specific area at a precise level eliminating unnecessary and
possibly dangerous drug delivery into undesired parts. Furthermore, control over the
current allows for different volumes of substance to be injected at different velocities with
little error. Researchers have even been able connect multiple actuators together allowing
for much higher volumes of a drug to be injected at once, something a traditional
hypodermic needle cannot do [4].
Why it is superior to hypodermic syringes and other jet injections:
To begin, the Lorentz-force actuator is a jet injector by nature. With the brand
of jet injector come the benefits and improved aspects absent in traditional hypodermic
needles and syringes. One of the largest problems facing hypodermic needles is the needle
itself. Not only are a large percentage of the population fearful of the traditional bloodsucking, pain-inducing needle, but its actual physical existence and usage create a myriad
of problems. Hypodermic needles are used to breach the skin, as seen in Fig. 2, and either
inject or absorb liquid drugs or bodily fluids.
Figure 2: A Example of needle penetration Source:
http://www.brooksidepress.org/Products/Administer_IM_SQ_and_ID_Injections/lesson_2_
Section_2.htm
Inherit in this functionality lies the dangers of unwanted transmitted materials between
patients. One simple misuse of a needle on two different individuals could spread life
ending and life altering infectious diseases like AIDS, HIV, or Hepatitis C. When individuals
administer drugs incorrectly, disasters like the 1960 hepatitis outbreak, which killed fifteen
people, occur leading a reevaluation of current standards [1]. As a result of this travesty,
glass syringes, which at the time where the common form of delivery method, were
replaced by cheap disposable plastic ones. Dramatic problems like the spread of
intravenous diseases are not prevalent in current jet injections because there is no
protrusion that physically penetrates the skin, but rather a strong jet of the desired
substance. Only diseases with a long life span and abnormally small spreading capability
carry the threat of transmission. However, this problem can be solved, like syringes, by
replacing the part of the jet injector that physically that touches the skin leading to a safe
and foolproof method of delivery.
Furthermore, jet injections lack the most feared part of any vaccine or
subcutaneous inoculation, the needle. Unfortunately, about 385,000 individuals
accidentally poke, prick, or injure themselves each year [2]. Combine this data with the
disturbing possibility that some of those needles bear life ending or altering diseases and a
recipe for trouble is formed. Jet injections of any form lack this vulnerability because the
nature of the system does not require a sharp object to penetrate the skin. Instead the only
requirement for dispensing the drug is that the ampoule be flush with the skin. This means
no part of the jet injector enters and only the drug, which is shot out of the ampoule,
punctures the epidermal tissue [5]. With this disposed threat, self-administration, for
diabetics or others forced to self-managed, becomes less of a meticulous undertaking and
more of a dull chore. Additionally, jet injectors allow the visually handicapped demographic
to easily self-medicate without the aid of others or the apprehension spurred by pain
should they fail to properly insert the needle.
Advantages over other Jet Injectors:
As of late, spring-loaded and gas powered jet injectors are widely in use.
There are few alternatives to these superior drug delivery systems despite the immense
advantage they hold over traditional hypodermic syringes. Fortunately, the Lorentz-force
actuator is in its testing stages and will undoubtedly dominate all forms of intramuscular
and intravenous drug delivery methods. The Lorentz force actuator is of higher-caliber
when compared to current models of jet injectors for two reasons: controlled delivery
speed and powder drug distribution.
The main selling point on this innovative technology lies with its
revolutionary ability to control the speed at which an individual can inject drugs into the
body. As seen in Fig. 2, the stream operates under a guiding set up principals controlled by
the laws of fluid dynamics, which are specific to each encountered surface. Additionally, the
speed at which the stream is injected is highly controllable because it follows the laws of
electricity and magnetism, previously explained, specifically, how current and magnetic
fields operate. A highly controllable stream means one can manipulate the area receiving
the drug, the duration for which it is received, and the depth of penetration all at the same
time and in a predictable manner, a feat previous jet
Figure 3: A stream of liquid into a pseudo-skin surface via Lorentz-force injector. Source:
[2]
injectors fail to accomplish. Gas jet injectors and spring loaded jet injectors are governed
by the properties of pressure and spring constants, forces that are difficult to control in a
timely manner due the limitations of existing technology. The influence one has over these
delivery techniques is limited to adjusting the speed of the injection prior to the shot [6]. As
a result, gas and spring injectors are inferior if say, a doctor whishes to administer a drug to
a specific area over a controlled amount of time. Trivial as it may seem, situations where a
patient needs aggressive medication to be inserted to a specific area make the attribute of
high controllability paramount.
The future of the Lorentz-force actuator:
In the near future, it is inevitable that posterity will incorporate Lorentz-force
drug injections in all areas current jet injections and hypodermic needles occupy. Scientists
are currently working on how to manipulate powdered drugs in such a way that they
behave as liquids and thus can be injected with similar predictability. Successful trials in
animals, of powdered injection via the Lorentz-force actuator, have been actualized and
human trials are soon to begin. Should human trials prove to be positive, the time
constraint current liquid vaccines come with will be shattered allowing for millions of
people to receive vaccinations in a cheaper and more efficient manner [2]. Since powdered
vaccines do not need to be cooled, there is not time requirement or temperature guidelines,
restrictions all liquid, hypodermic vaccines must abide by.
As is stands, the Lorentz-force actuator is not a cost efficient method through
which vaccines or shots can be administered. The technology is young and requires further
research until is can be a sustainable, everyday household or hospital item. Also, scientists
are still exploring its ability to insert drugs in different parts of the body. The future
implications may result in a universal drug administration device with the ability to inject
and even retract powders and liquids to a wide array of locations on or in the body.
Research in this device will allow for an awesome medical device capable of saving billions
of lives and revolutionizing the medical field.
Bibliography
[1] Jackie Rosenhek. (2009, March). Needle trade. Doctor’s Review. [Online] Available:
http://www.doctorsreview.com/history/needle-trade/
[2] Jennifer Chu. (2012, May 24). Device may inject a variety of drugs without using needles.
MIT News. [Online]. Available: http://web.mit.edu/newsoffice/2012/needleless-injections0524.html
[3] Randall D. Knight, “Electromagnetic Fields and Waves,” Physics for scientists and
engineers a strategic approach. 3rd edition. Glenview Illinois: Person Education, 2004, ch.
34, pp. 1003-1026.
[4] Carl Franzen. (2012, May 25) No more needles: MIT develops high-powered liquid
injection device. TPM IdeaLab. [Online]. Available:
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pers/0808.pdf
[6] Anubahav Arora, Mark Prausnitz, and Samir Mitragotri, (2008, December 8). Microscale device for transdermal drug delivery. National Institute of Health Public Access.
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[7] Roberta Kwok. (2011 May 26). The real issue in vaccine safety. Nature. [Online]. pp.
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[8] C. M. Peterson, J.P. Palmer, L. Jovanovich-Peterson, and S Sparks. (1993, November).
Jet-Injected insulin is associated with decreased antibody production and postprandial
glucose variability when compared with needle-Injected women in gestational diabetic
women. Diabetes Care. [Online]. pp. 1474-1484. Available:
http://care.diabetesjournals.org/content/16/11/1479.full.pdf+html
[9] David W. Parker, “Hypodermic Syringe,” U.S. Patent 6,706,019, March, 16, 2004.
[10] R Kravetz, ‘Hypodermic Syringe’, The American Journal of Gastroenterology, 100
(2005), pp 2614–2615
[11] Shots without needles. Path. [Online]. Available:
http://www.path.org/projects/jet_injector.php
[12] K. Chen, H. Zhou, and G. J. Cheng. (2010, Oct 01). A model on liquid penetration into
soft material with application to needle-free jet injection. Journal of Biomedical Engineering.
[Online]. 132(10).