Biomedical Engineering Reference
In-Depth Information
temperature recordings and mechanical contact during ablation were demonstrated on beating
rabbit and rat hearts.
Similarly, the company CardioMEMS has developed a wireless, battery-less, RF-activated
pressure sensor the size of a paper clip that is implanted into the pulmonary artery and that has
demonstrated a 30% lower risk of ending up in the hospital for heart failure. he device, which
is now approved by the FDA, is activated with a wand-like device as it is positioned over the
implant area. he pressure sensor transmits real-time data to an external unit, which then com-
municates this information to the patient's physician (who can efectively monitor the patient
remotely without requiring the patient to come to the hospital, thus reducing the cost of health-
care and increasing the quality of life substantially).
8.4.3 “Gecko” Surgical Tape
A large collaborative team led by Jefrey Karp at Harvard Medical School has developed a bio-
degradable polymeric tape that sticks to tissue because its surface is covered with nanopillars
(
Figure 8.18
)—a strategy inspired on the feet of Geckos. he adhesion strength of nanopat-
terned
poly(glycerol sebacate acrylate) (PGSA)
was nearly twofold greater than the adhesion
strength of lat unpatterned polymer. he surface of the pillars is coated with a sugar-based
“glue” to close a surgical incision, and because it is made of poly(glycerol sebacate acrylate)
(PGSA), it completely degrades over time. PGSA is an elastomer that can be made more or less
stretchable (e.g., for a heart patch) and can be loaded with drugs that help tissue heal (i.e., “active
band-aids”).
a
b
Silicon template
UV light
10 µm
PGSA
prepolymer
PGSA pillars
1 µm
Patterned
PGSA elastomer
3
2.5
2
1.5
0.37
2.
2
c
0.40
0.
87
0.18
2.7
0.40
2.1
1
0.5
0
Oxidized-Dextran
coating
0
0.2
0.4
Tip diameter/pitch
FIGURE 8.18
Biodegradable.“gecko-inspired”.adhesive.surface..(From.A..Mahdavi,.L..Ferreira,.C..
Sundback,.J..W..Nichol,.E..P..Chan,.D..J..D..Carter,.C..J..Bettinger,.S..Patanavanich,.L..Chignozha,.
E..Ben-Joseph,.A..Galakatos,.H..Pryor,.I..Pomerantseva,.P..T..Masiakos,.W..Faquin,.A..Zumbueh,.
S..Hong,.J..Borenstein,.J..Vacanti,.R..Langer,.and.J..M..Karp,.“A.biodegradable.and.biocompatible.
gecko-inspired.tissue.adhesive,”.
Proc. Natl. Acad. Sci. U. S. A.
,.105,.2307-2312,.2008..Copyright.
(2008).National.Academy.of.Sciences,.U..S..A.)
