Impedance spectroscopy: A tool for real‐time in situ monitoring of the degradation of biopolymers

Abstract

241 600 953 235Investigation of the degradation kinetics of biodegradable polymers is essential for the development of implantable biomedical devices with predicted biodegradability. In this work, an impedimetric sensor has been applied for real-time and in situ monitoring of degradation processes of biopolymers. The sensor consists of two platinum thin-film electrodes covered by a polymer film to be studied. The benchmark biomedical polymer poly(D,L-lactic acid) (PDLLA) was used as a model system. PDLLA films were deposited on the sensor structure from a polymer solution by using the spin-coating method. The degradation kinetics of PDLLA films have been studied in alkaline solutions of pH 9 and 12 by means of an impedance spectroscopy (IS) method. Any changes in a polymer capacitance/resistance induced by water uptake and/or polymer degradation will modulate the global impedance of the polymer-covered sensor that can be used as an indicator of the polymer degradation. The degradation rate can be evaluated from the time-dependent impedance spectra. As expected, a faster degradation has been observed for PDLLA films exposed to pH 12 solution.

Micromachined multi‐parameter sensor chip for the control of polymer‐degradation medium

“…As can be seen, after the medium had been changed towards basic conditions (solution 3), a faster decrease of the impedance signal was observed, indicating an accelerated polymer degradation. Such a behaviour is in agreement with our previous results on PDLLA-degradation measurements using an impedimetric sensor [12] and is explained by the accelerated hydrolysis of the ester bonds of PDLLA under alkaline conditions [11].…”

“…More recently, the potential of a chip‐based approach for the real‐time in situ monitoring of the degradation kinetics of biopolymers by applying semiconductor field‐effect devices based on a capacitive electrolyte–insulator–semiconductor (EIS) structure and impedimetric sensors was successfully demonstrated . The polymer‐degradation process is very complex and is affected by a number of factors such as physico‐chemical properties of biopolymers, their sterilization process, storage history and shape . The physico‐chemical parameters affecting the degradation kinetics include, for instance, the polymer structure and morphology (amorphous/crystalline), mechanical properties, hydrophilicity/hydrophobicity, molecular weight, etc.…”

Monitoring of the Enzymatically Catalyzed Degradation of Biodegradable Polymers by Means of Capacitive Field-Effect Sensors

“…As a model polymer, commercial PDLLA with a syndiotactic order of the two enantiomers d - and l -lactic acid, a molecular mass in the range of M w = 10 000–18 000 Da and a free carboxylic acid as the end group was used (RESOMER R 202 H, Evonik Röhm GmbH, Germany). The deposition of the polymer layer on the sensor structure was performed in analogy to the procedure described in previous works. ,− The polymer was solved in methyl ethyl ketone with a concentration of 96 mg/mL and was applied to the sensor surface by means of a spin-coating process. The thickness of the prepared polymer layers was measured using a subset of sensor chips, where part of the polymer layer was scraped off and the height difference of the layer was determined by means of profilometry.…”

Reaction tubes: A new platform for silicon nanophotonic ring resonator sensors

“…Label-free detection is a solution to this involving a transducer that directly measures some physical property of the biological compound. This transducer can be mechanical [2,3], electrical [4,5], or optical [6,7].…”