sutures have been studied widely in the recent years due to their advanced
biological properties. Sutures are biomaterial devices used for a wide
range of applications including approximating tissues, connecting hollow
structures and for the ligation of blood vessels. Due to the adaptability of
polymeric sutures to different conditions, they are preferred over other
materials for targeted drug delivery. Sutures have been found to be a
remarkable strategy for the delivery of antibacterial agents or
anti-inflammatory drugs to the surgical site. This system provides
a controlled release profile of drug thus achieving high local drug concentrations
without excessive systemic levels. Polymeric sutures when in used surgical procedures
they do not require separate procedure for placing the drug system like
implants into the surgical bed. Thus avoiding the unwanted generation of nidus
for infection and also prevents hindering the wound healing process. There are two
main types of polymeric sutures: Absorbable sutures and Non-Absorbable sutures.
Among them Absorbable/Biodegradable sutures have undergone immense research
since they have potential for effective drug delivery. On the basis of their
origin, absorbable sutures are further classified into 2 types Natural and Synthetic.
Natural absorbable suture like catgut is obtained from the
connective tissue of beef or sheep intestines. Synthetically derived absorbable
sutures are fabricated using polymers like polyglycolic acid, polylactic acid,
PLGA and Polydioxanone, poliglecaprone 25 and Vicryl – Rapide. These sutures absorb anywhere between
10 days to eight weeks depending on the material used in making them. Non-absorbable sutures are made up of Nylon, polyester, Polyvinylidene
fluoride (PVDF), polypropylene, ultra-high molecular weight polyethylene
(UHMWPE) etc. The material for fabrication of these sutures are selected
depending on their intended application. Silk is the original non-absorbable
suture material derived from an organic protein called fibroin.
The design of suture is a critical parameter because it finally affects the
suture quality. Physical and mechanical properties like suture size, tensile
strength, stiffness etc is important in suture selection in order to avoid
unexpected breakage during use.
Drugs or biomolecules are loaded in/ onto the sutures either during fabrication
or after fabrication, using various techniques namely Electrospinning, Melt
spinning, Dip coating and Radiation Grafting. Recently reported polymeric
sutures provide controlled drug release of various therapeutic agents like
antimicrobials, natural extracts, proteins, transcription factors, plant stem
cells. For achieving a systematic and controlled delivery of drug through this
system it should be designed in a way that it retains its mechanical integrity
as long as it is required to ensure complete wound healing. These are recent
developments in sutures for improving mechanical properties, but designing
sutures with all the desirable properties is still under investigation.