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Open Access Technical advance

A method to screen and evaluate tissue adhesives for joint repair applications

Tilo Dehne1*, Rolf Zehbe2, Jan Philipp Krüger3, Aneliya Petrova4, Rafael Valbuena4, Michael Sittinger1, Helmut Schubert2 and Jochen Ringe1

Author Affiliations

1 Tissue Engineering Laboratory and Berlin-Brandenburg Center for Regenerative Therapies, Department of Rheumatology and Clinical Immunology, Charité-Universitätsmedizin Berlin, Föhrer Strasse 15, Berlin 13353, Germany

2 Institute of Materials Science and Technologies, Technische Universität Berlin, Englische Strasse 20, Berlin 10587, Germany

3 TransTissue Technologies GmbH, Charitéplatz 1, Berlin 10117, Germany

4 Institute of Agricultural and Urban Ecological Projects, Humboldt Universität Berlin, Philippstr. 13, Berlin 10115, Germany

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BMC Musculoskeletal Disorders 2012, 13:175  doi:10.1186/1471-2474-13-175

Published: 17 September 2012

Abstract

Background

Tissue adhesives are useful means for various medical procedures. Since varying requirements cause that a single adhesive cannot meet all needs, bond strength testing remains one of the key applications used to screen for new products and study the influence of experimental variables. This study was conducted to develop an easy to use method to screen and evaluate tissue adhesives for tissue engineering applications.

Method

Tissue grips were designed to facilitate the reproducible production of substrate tissue and adhesive strength measurements in universal testing machines. Porcine femoral condyles were used to generate osteochondral test tissue cylinders (substrates) of different shapes. Viability of substrates was tested using PI/FDA staining. Self-bonding properties were determined to examine reusability of substrates (n = 3). Serial measurements (n = 5) in different operation modes (OM) were performed to analyze the bonding strength of tissue adhesives in bone (OM-1) and cartilage tissue either in isolation (OM-2) or under specific requirements in joint repair such as filling cartilage defects with clinical applied fibrin/PLGA-cell-transplants (OM-3) or tissues (OM-4). The efficiency of the method was determined on the basis of adhesive properties of fibrin glue for different assembly times (30 s, 60 s). Seven randomly generated collagen formulations were analyzed to examine the potential of method to identify new tissue adhesives.

Results

Viability analysis of test tissue cylinders revealed vital cells (>80%) in cartilage components even 48 h post preparation. Reuse (n = 10) of test substrate did not significantly change adhesive characteristics. Adhesive strength of fibrin varied in different test settings (OM-1: 7.1 kPa, OM-2: 2.6 kPa, OM-3: 32.7 kPa, OM-4: 30.1 kPa) and was increasing with assembly time on average (2.4-fold). The screening of the different collagen formulations revealed a substance with significant higher adhesive strength on cartilage (14.8 kPa) and bone tissue (11.8 kPa) compared to fibrin and also considerable adhesive properties when filling defects with cartilage tissue (23.2 kPa).

Conclusion

The method confirmed adhesive properties of fibrin and demonstrated the dependence of adhesive properties and applied settings. Furthermore the method was suitable to screen for potential adhesives and to identify a promising candidate for cartilage and bone applications. The method can offer simple, replicable and efficient evaluation of adhesive properties in ex vivo specimens and may be a useful supplement to existing methods in clinical relevant settings.

Keywords:
Tissue adhesive; Bonding strength; Cartilage; Bone; Transplant; Tissue engineering; Joint repair; Test method