Bio-functional coating for biodegradable metallic implants inhibits corrosion and prevents inflammation and infection.
Commonly used metallic implants include stainless
steels, titanium, and cobalt-chromium-based alloys. These biomaterials are somewhat limited and can
cause negative affects on the body, such as the
release of toxic metallic ions and/or particles through
corrosion or wear processes. These toxins can lead to
inflammatory issues in patients. Permanent metallic fixtures can trigger infections, increasing the
liklihood of repeat surgeries and an increase in
healthcare cost. Current metallic biomaterials have
vastly different propeties than natural bone tissue,
resulting in stress shielding effects that can lead to
reduced stimulation of new bone growth and
decreased implant stability.
Several challenges exist for
the long term presence of
metallic implants, especially
in applications that require
only short-term support for
healing. Although metals
present these concerns, they
are much more dependable
than polymers and ceramics. This leads to the development
and research of biodegradable
metals. This is a new concept
within medicine that presents
solutions to the problems that
are raised with the use of
traditional metals.
Magnesium (Mg) and its alloys are being explored as a potential biodegradable metallic implants by researchers
at Wichita State University. This substance can provide both better physiological repair, as well as superior
reconstruction of vascular tissues with minimum inflammatory response. The body’s fourth most plentiful metal
is magnesium, and some studies have shown that its ions are able to inhibit platelet activation. The corrosion of
magnesium-based implant involves the formation of a non-toxic by-product that is harm to the body.
APPLICATION:
Wichita State researchers have developed coating on magnesium
to control its biodegradation, surface modification for localized
therapeutic delivery, development of in-vitro biodegradation test
methods and modeling to predict biodegradation behavior. Their
focus on this is to eliminate the concerns of metallic implants by
coating each implant in a harmless, biodegradable substance.
The global orthopedic trauma ĕxation devices market is expected
to grow from $5.5 billion in 2012 to $9.3 billion by 2020.
Currently, stainless steel, cobalt, and titanium are the most
common metals used for implants. Mismatch in bone and metal
properties leads to many complications and repeat surgeries. The
use of biodegradable metals is the natural next step in improving
metallic implants.
BIODEGRADABLE METALLIC IMPLANTS:
Magnesium based materials and its alloys are one of the materials under investigation for its potential
applicability as a metallic biodegradable implant. With a density of 1.74 grams per cubic centimenter,
it is considered a lightweight material. It is 1.6 times less dense than aluminum and 4.5 times less dense
than steel. The potential is there for it to serve as a lightweight, biodegradable implant material that
would remain present in the body and
maintain its mechanical integrity over a
predetermined time scale while the tissue
heals.
Dr. Mahapatro and his team’s invention
demonstrates a hybrid coating strategy
that provides a corrosion-inhibiting,
bio-functional coating for magnesium
based materials for development of
biodegradable metallic implants. This
coating consists of two layers. The first is a base coating that provides long term corrosion resistance. The top
layer is a functional coating that caters to bio-functionality requirements including: drug delivery for prevention
of stent restenosis, tissue integration, and antibacterial properties for orthopedic fracture management devices.
A magnesium based implant has the capability to be installed similarly to metallic implants through a
surgical process; however, the biodegradation of Dr. Mahapatro’s invention is much better for the body.
There are adhesive elements to the implant that connect the biodegradable device to the at-risk area.
The device is resistant to biocorrosion, and at the same time, it will eventually be biodegraded as the tissue
it was replacing heals and redevelops. There is little toxicity involved in this process, which makes it a much
more suitable and desirable piece of equipment. Eventually, the implant will be non-existent, and the patient
will have a healed body part.