Scaffolds with shape memory behavior for the treatment of large bone defects

Abstract

The aim of the presented study was preparation, analysis of properties, and in vitro characterization of porous shape-memory scaffolds, designed for large bone defects treatment using minimally invasive surgery approach. Biodegradable terpolymers of l-lactide/glycolide/trimethylene carbonate (LA/GL/TMC) and l-lactide/glycolide/ε-caprolactone (LA/GL/Cap) were selected for formulation of these scaffolds. Basic parameters of shape memory behavior (i.e. recovery ratio, recovery time) and changes in morphology (SEM, average porosity) and properties (surface topography, water contact angle, compressive strength) during shape memory cycle were characterized. The scaffolds preserved good mechanical properties (compressive strength about 0.7 to 0.9 MPa) and high porosity (more than 80%) both in initial shape as well as after return from compressed shape. Then the scaffolds in temporary shape were inserted into the model defect of bone tissue at 37°C. After 12 min the defect was filled completely as a result of shape recovery process induced by body temperature. The scaffold obtained from LA/GL/TMC terpolymer was found the most prospective for the planned application thanks to its appropriate recovery time, high recovery ratio (more than 90%), and cytocompatibility in contact with human osteoblasts and chondrocytes.

Influence of Radiation Sterilization on Properties of Biodegradable Lactide/Glycolide/Trimethylene Carbonate and Lactide/Glycolide/ε-caprolactone Porous Scaffolds with Shape Memory Behavior

“…Scaffolds were produced via solvent casting/particulate leaching technique using the same porogen (sodium chloride particles) [17,20]. Obtained scaffolds had a similar average porosity and diameter of pores.…”

“…Using the same procedure of scaffold preparation and methods of their sterilization (not exceeding a dose of 10 kGy), we would like to examine whether the sterility at the sterility assurance level (SAL) of 10 −6 is possible. It is worth mentioning that, as presented in this study, scaffolds sterilized with electron beam at 10 kGy dose were successfully applied for evaluation of their cytotoxicity and shape memory properties in in vitro conditions [17]. …”

“…Results related to effectiveness of proposed scaffolds in minimally invasive surgery for bone defects treatment have already been published by us [17,18]. …”

Responsive Biomaterials: Advances in Materials Based on Shape‐Memory Polymers

“…Interestingly, hydration-responsive chitosanbioglass composite tissue scaffolds have been shown to rapidly fill bone defects in vivo, [54] as have body temperature-responsive copolymers of L-lactide/glycolide/trimethylene carbonate or L-lactide/glycolide/epsilon (Figure 3). [55] Electrospun mats of temperature-responsive biodegradable SMPs based on…”

Biodegradable shape memory polyurethanes with controllable trigger temperature

“…The trigger temperature could be tuned around body temperature by controlling the molecular weight and gel content [35] . Biodegradable terpolymers of L-lactide/glycolide/-caprolactone (LA/GL/Cap) were selected for porous shape-memory scalffolds by Rychter et al [36] . The shape recovery process could be induced around body temperature in 12 min.…”