Capturing the Real-Time Hydrolytic Degradation of a Library of Biomedical Polymers by Combining Traditional Assessment and Electrochemical Sensors

Abstract

We have developed an innovative methodology to overcome the lack of techniques for real-time assessment of degradable biomedical polymers at physiological conditions. The methodology was established by combining polymer characterization techniques with electrochemical sensors. The in vitro hydrolytic degradation of a series of aliphatic polyesters was evaluated by following the molar mass decrease and the mass loss at different incubation times while tracing pH and l -lactate released into the incubation media with customized miniaturized electrochemical sensors. The combination of different analytical approaches provided new insights into the mechanistic and kinetics aspects of the degradation of these biomedical materials. Although molar mass had to reach threshold values for soluble oligomers to be formed and specimens’ resorption to occur, the pH variation and l -lactate concentration were direct evidence of the resorption of the polymers and indicative of the extent of chain scission. Linear models were found for pH and released l -lactate as a function of mass loss for the l -lactide-based copolymers. The methodology should enable the sequential screening of degradable polymers at physiological conditions and has potential to be used for preclinical material’s evaluation aiming at reducing animal tests.

Pliable, Scalable, and Degradable Scaffolds with Varying Spatial Stiffness and Tunable Compressive Modulus Produced by Adopting a Modular Design Strategy at the Macrolevel

“…This heterogeneous structure is the reason why mechanical properties of breast tissue differ significantly from those of pure adipose tissue and renders their assessment difficult. − Over time, scaffold degradation and the consequent decrease in mechanical properties will stimulate native tissue growth and scaffold replacement. This requires a pliable scaffold with a more rapid degradation time then that for PCL, others have suggested a need for a supportive structure for 6–8 months or up to a year. , This correlates with our initial degradation data provided on thin PCLDX films, which showed a bulk degradation with polymer reaching the threshold for intracellular digestion in a time frame of 9 months. , It also correlates with the degradation of the mesh. The TIGR Matrix consists of two aliphatic polyesters fibers, one where the mechanical properties are retained for 2 weeks, resulting in a reduced stiffness after this time frame .…”

“…12,14 This correlates with our initial degradation data provided on thin PCLDX films, which showed a bulk degradation with polymer reaching the threshold for intracellular digestion in a time frame of 9 months. 10,34 It also correlates with the degradation of the mesh. The TIGR Matrix consists of two aliphatic polyesters fibers, one where the mechanical properties are retained for 2 weeks, resulting in a reduced stiffness after this time frame.…”

Factors Controlling Degradation of Biologically Relevant Synthetic Polymers in Solution and Solid State

“…In situ techniques, like sum-frequency generation (SFG) and in situ AFM, have been used to characterize chemical and morphological surface changes but are not as accessible as other techniques. Recently, selective electrochemical sensors were developed to trace polymer degradation in real time by measuring pH and degradation product concentrations, but the samples were still removed from solution, washed, and dried for weight-loss measurements . Sensors have also been used to track biodegradation of polymers by enzymes and cell supernatants .…”

“…Recently, selective electrochemical sensors were developed to trace polymer degradation in real time by measuring pH and degradation product concentrations, but the samples were still removed from solution, washed, and dried for weight-loss measurements. 138 Sensors have also been used to track biodegradation of polymers by enzymes and cell supernatants. 139 These advancements in real-time measurements may improve the accuracy of sequential in vitro screenings by reducing the perturbation of the samples from rinsing and drying steps.…”

Degradable biomedical elastomers: paving the future of tissue repair and regenerative medicine

“…It presents new insights into mechanisms for evaluating degradable implants. 53 Enzymatic degradation of substrates in vivo was discussed in detail above, so this is an integral part of performing in vitro simulations. We evaluated the degradation properties of the elastomers using in vitro enzymatic degradation assays, specifically in phosphate buffer solution (PBS) (pH 7.4) using thermoanaerobacter langsdorferi lipase with an activity of 2000 U mL À1 at 37 1C.…”