Biomedical Engineering Reference
In-Depth Information
(A)
(B)
10 µm
HV
15.00 kV
WD
9.7 mm
mag
5000 ×
det
LFD
HFW
29.8 μm
Doxy
NST
BHU
Figure 21.1
Poly(ε-caprolactone) nanofibers containing doxycycline were successfully electronspun and
evaluated clinically for peridontal diease. (A) Scanning electron micrograph to show the surface mor-
phology of nanofiber. (B) Clinical photograph showing the insertion of the nanofiber into the periodontal
pocket. Reproduced from [52] with permission by the Journal of Clinical and Diagnostic Research.
as antibiotics, can be delivered in a noninvasive, precise, timed, and more importantly,
targeted manner to the desired location within the body [52]. Advantages of such local
drug-delivery systems include: better accessibility, low enzymatic activity, and painless
administration [52]. An example of such a system was reported recently whereby the effec-
tiveness of doxycycline nanofibers, in conjunction with nonsurgical periodontal therapy or
deep cleaning, were evaluated in the treatment of chronic periodontitis [52].
Doxycycline is one of the most common broad-spectrum antibiotics that is effective in
managing most periodontal infections, owing to its low minimum inhibitory concentration
(MIC), its antibacterial protein synthesis and anti-inflammatory properties [53]. In addition,
doxycycline can bind to hard tissue of a periodontal pocket and act as a drug reservoir.
Doxycycline incorporated with biodegradable polymers such as poly(ε-caprolactone) (PCL)
nanofibers have been investigated for the treatment of periodontal infections in which the
nanofibers have been inserted directly into the base of the infected periodontal pocket to fill
its depth and curves (Figure 21.1) [53]. It was shown that such nanofibers were able to
maintain drug concentrations while achieving a sustained release of doxycycline for a
minimum of 19 days with low burst release. Furthermore, in all cases, nanofibers main-
tained their smoothness and flexibility and did not shrink during the treatment period [53].
These properties, together with the ease of implantation of the nanofibers, their cost, and
time effectiveness, can prove ideal in the treatment of infected periodontal diseases.
poss-pcU N
aNocomposite
m
aterial
The materials currently used in soft tissue regener-
ation, which include collagen, hyaluronic acid, silicon, and other filler materials, have several
disadvantages such as high cost, immunogenicity, and the risk of transmitting infectious
diseases. This lack of progress has inspired a fresh perspective and provoked further investi-
gation and development in this field of tissue engineering. Since 2005, our laboratory
have developed biodegradable and nonbiodegradable nanocomposite scaffolds based on
incorporating a polyhedral oligomeric silesquioxane (POSS) nanocage into polyurethanes
for organ regeneration [54, 55]. Polyurethanes are adaptable copolymers that have been used
for biomedical devices for several decades [56].
The nonbiodegradable nanocomposite polymer POSS-PCU consists of POSS combined
with poly(carbonate-urea) urethane, a synthetic polymer already used in medical implants
and devices [55]. The POSS molecule is a nanoparticle, which has dimensions in the order of
