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Advancement of adhesives technology has been limited in orthopedics, which still has a striking reliance on metal hardware to help facilitate fracture healing. Despite an obvious clinical need, bone adhesives are not currently available on the market. Testing the bone adhesion strength and other aspects of the adhesive performance is extremely complex. This paper presents standardized methodology for in vitro assessment of bone-to-bone adhesion strength. Two test configurations (lap shear and butt joint) were used to comparatively assess the adhesion strength of four commercially available adhesive material, poly(methyl methacrylate) cement (CMW), glass-ionomer cement (FUJI), dimethacrylate resin (SB) and cyanoacrylate resin (VB), which were allowed to set under two environmental conditions (air and water). Under dry conditions, both test configurations generally yielded similar measurements of adhesion strength, which was around 1.1, 2.8 and 9.1 MPa for CMW, FUJI and VB, respectively. The dry adhesion strength for SB measured using the butt configuration (2.5 MPa) was 43.2% higher compared to that measured using lap shear (1.4 MPa). In a wet environment, the measured adhesion strength generally decreased and was dependent on the test configuration used. The failure mode of the samples adhered using CMW was adhesive, while that using FUJI, SB and VB was a combination of both adhesive and cohesive, independent of the test configuration and the setting condition. This proposed methodology is comparable to ASTM standards and can be used to study the effect of different biomaterial formulations as well as test parameters on the bone-to-bone adhesion strength, in a reproducible manner. [ABSTRACT FROM AUTHOR]

Surgical sealants are widely used in cardiothoracic and vascular surgery essentially for hemostasis and sealing. Their adhesive properties have mainly been studied by clinical experiments. The objective of this study is to measure adhesion of the three main types of surgical sealant used in cardiothoracic and vascular surgery under normalized realistic conditions. The bulge-and-blister test was used to quantify adhesive performances of three types of surgical adhesives: cyanoacrylates, polyethylene glycol (PEG), and aldehydes. Samples were composed of two circular layers of equine pericardium glued by the surgical sealant studied. Comparative adhesion testing was carried out in eight samples bonded with a Dermabond ® (cyanoacrylate), five samples with Bioglue ® (aldehyde), four samples with Coseal ® (PEG), and thirteen samples bonded with an industrial cyanoacrylate. Scanning electron microscope (SEM) observations of cross-sections of samples glued by Dermabond ® and environmental scanning electron microscopy (ESEM) images of samples composed of equine pericardium glued by Bioglue ® were also performed. The average value of the adhesion energy is 2.3+/−1.5 J.m −2 for samples glued with Dermabond ® , 6.04+/−1.61 J.m −2 with Bioglue ® , 2.37+/−1.25 J m −2 with Coseal ® , 3.74+/−1.33 J m −2 with the industrial cyanoacrylate glue in surgical conditions. SEM observations of cross-sections of samples glued by Dermabond ® showed a failure at the interface between the glue and the pericardial layer. ESEM observations have revealed a majority of regions where the glue is not linked to the pericardium. Adhesive performance measurements and microscopy observations in surgical conditions show that surgical sealants adhesion is weak and explain their poor efficacy in clinical practice. To improve adhesion in the surgical field, we need to focus on achieving a better cohesion between the adhesive and the substrate by modifying conditions adhesive bonding and consequently tend toward cohesive failure. [ABSTRACT FROM AUTHOR]

Abstract: The idea of being able to glue bone fragments with a suitable biocompatible adhesive remains highly attractive to orthopaedic surgeons. Yet despite decades of research, no suitable system that fully meets all the many requirements for such an adhesive has yet been identified. This article reviews the requirements and challenges of developing a bone adhesive for fracture repair and also the substantial progress that has been made. Developments in bone adhesives can roughly be classified into two groups: synthetic and biologically-derived/inspired. Early examples of synthetic adhesives include poly(methyl methacrylate) and related polymers, cyanoacrylates and polyurethanes. These materials are characterised by relatively good mechanical properties but often lack the required biocompatibility and biodegradability. More recent adhesive systems based on lactide–methacrylate chemistry therefore attempt to address these issues. Similarly, there is renewed interest in glass ionomer cements and calcium/magnesium phosphate cements. Biological adhesives include fibrin and gelatin-based systems. These have good biocompatibility and biodegradability but lack the cohesive strength to have good adhesion to bone and are used chiefly in soft tissue applications. Newer examples that are looking more promising include adhesives inspired by mussel adhesive proteins and the “sandcastle glue” of the marine worm Phragmatopoma californica. As well as the challenge to develop the adhesive systems themselves a further need is for greater consistency in the testing of adhesion to bone both in vitro/ex vivo and in vivo. Test methods in the literature are reviewed together with considerations for the design of such tests. [Copyright &y& Elsevier]

Silk fibroin is a natural proteinaceous material that can be readily obtained from the cocoons produced by domesticated silkworms (Bombyx mori). Due to remarkable physicochemical properties, this protein has been extensively investigated, and found promising applications in biomedicine and bioengineering. Over the past three decades, its potential use as a component of surgical adhesives/sealants has been also occasionally explored. This review discusses critically the existing research literature, showing both the achievements and the limitations or disputable results. An inescapable conclusion is that more research work is needed to establish a functional relevance for silk fibroin in surgical adhesive formulations. So far as the author is aware, all publications related to the topic are covered in this review. [ABSTRACT FROM AUTHOR]