Development of bioactive nano-fiber thread that can incorporate and release various growth factors

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 18500365
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Biomedical engineering/Biological material science
• Research Institution: Osaka City University
• Principal Investigator: KAZUKI Kenichi Osaka City University, Graduate School of Medicine, Associate Professor (80254407)
• Co-Investigator(Kenkyū-buntansha): TAKAOKA Kunio Osaka City University, Graduate School of Medicine, Professor (30112048) ; OKADA Mitsuhiro Osaka City University, Graduate School of Medicine, 登録医 (40309571)
• Project Period (FY): 2006 – 2007
• Keywords: Fibroblast Growth Factor; FGF / Drug Delivery System; DDS / Biodegradable synthetic polymer / Tendon suture / Tendon wound healing / 腱治癒

Research Abstract

We have developed a new bioactive thread that can promote tendon healing processes. A network structure in the nano-fiber thread can contain various growth factors and biodegradable synthetic polymers, and so this thread in itself is able to have the bioactive function of drug delivery system (DDS). We used the combination of basic fibroblast growth factor (bFGF) which enhanced reparative processes after tendon injury and polyethylene glycol (PEG) which was one of the biodegradable synthetic polymers.
We used an in vivo rabbit tendon repair model (n=40). This nano-fiber thread was soaked in PEG (500mg) with or without bFGF solution (500μg/ml). The flexor tendon of the rabbit's hind limb was cut sharply and repaired by end to end suture, according to the method of Kessler using 5-0 nylon threads and peripheral running suture using nano-fiber thread coated with PEG and bFGF (FGF Group) or with PEG only (PEG Group). The suture sites were examined histologically (hematoxylin-eosin staining) and biomechanically (ultimate load) at 3 and 6 weeks after surgery.
Histologic analysis showed that the epitenon thickening and cellular infiltration at the repaired site were vigorous in FGF Group at 3 and 6 weeks. Biomechal analysis showed that the ultimate load was significantly higher in FGF Group (31.8±3.8N) compared with PEG Group (24.3±3.4N) at 3 weeks after surgery. At 6 weeks the ultimate load in FGF Group (52.5±3.5N) was higher compared with PEG Group (43.7±4.7N), but there was no significant difference.
We developed a new bioactive nano-fiber thread incorporating FGF that induced an increase of biomechanical strength and a thickening of the epitenon layer in vivo. This system can accelerate tendon healing at an early stage and may become a therapeutic tool to be used in surgery.