A Novel Bioactive Suture That Accelerates Wound Tensile Strength Re-establishment And Enhances Wound Healing
Yulong Zhang1, Pin Ha1, Torie Tsuei2, Jean Woo Mok3, Lauren Irwin2, Xiaoxiao Pang1, Shivani Subhedar2, Yeganeh Amini2, Hsin Chuan Pan1, Emily A. Berthiaume4, John Ingrao2, Ben Wu1,2, Zhong Zheng1, Kang Ting1,5, Chia Soo5.
1UCLA dentistry school, Los angeles, CA, USA, 2UCLA Bioengineering, Los angeles, CA, USA, 3UCLA Institute for Society and Genetics, Los angeles, CA, USA, 4UCLA David Geffen School of Medicine, Los angeles, CA, USA, 5UCLA, Orthopaedic Hospital Department of Orthopaedic Surgery, Los angeles, CA, USA.
PURPOSE: Sutures are essential medical devices for tissue approximation to achieve wound healing. Unfortunately, conventional sutures only serve as passive bystanders as they are limited to mechanical approximation, but not biological activation of cells to promote healing. When conventional sutures are applied to wounds with excessive mechanical loading, such as in cleft lip and palate repair, there is a high risk of wound dehiscence. To create improved suture devices, we developed SLI-F06 peptide coated sutures that introduce innovative bioactive properties. The SLI-F06 peptide actively promotes cell migration, cell contraction, and collagen cross-linking. We hypothesize that SLI-F06 coated sutures will accelerate wound tensile strength re-establishment to enhance wound healing.
METHODS: To test our hypothesis, SLI-F06 coated absorbable sutures were fabricated using a scalable, cost-efficient lyophilization process. The suture types (monofilament suture and braided suture) and fabrication procedures (simple lyophilization, polymer coating, and layer-by-layer coating) were compared and optimized based on in vitro characterizations, including scanning electron microscope (SEM), mechanical strength, loading capacity, and release kinetics. In vivo efficacy of the coated sutures was evaluated using primary wound closure on a Yorkshire pig model. 4.0-cm length × 0.5-cm width full thickness wounds (n=6) were prepared and approximated by sutures with or without SLI-F06 coating, respectively. The wound tissues were harvested 4 weeks post-surgery. The breaking strength of the closed wound was measured by Instron, the gross appearance of the wounds was determined by visual analogue scale assessment, and histological analysis was conducted to examine biocompatibility.
RESULTS: Compared to the monofilament sutures, the braided sutures can be loaded with considerably more SLI-F06 peptide (0.039 vs. 0.1 mg/cm). Regardless of the coating method, SLI-F06 coating did not significantly alter the morphology and/or tensile strength of the sutures. The release kinetics of SLI-F06 from the sutures can be adjusted using different coating technologies, and in particular, the layer-by-layer coating technology led to a unique biphasic (immediate and extended) release pattern. Importantly, in Yorkshire pig wounds, using SLI-F06 coated suture resulted in significantly increased wound breaking strength (1.55-fold), an improved gross appearance 4-weeks post-injury, and equivalent inflammatory infiltration as the uncoated suture.
CONCLUSIONS: In summary, our results demonstrate that the innovative SLI-F06 coated sutures successfully promote wound healing by accelerating mechanical strength re-establishment and improving gross appearance, with no detectable adverse effects in this investigation. Unlike passive conventional sutures, these new bioactive SLI-F06 coated sutures significantly improved the wound healing process. Overall, this may decrease adverse clinical outcomes such as wound dehiscence in high risk patients with compromised healing or with high-tension wounds.
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