Selecting the correct scaffold model for assessing of the dielectric response of collagen-based biomaterials

Fish collagen (Col) was cross-linked using two methods: dehydrothermal treatment (DHT) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) in the presence of N-hydroxy-succinimide (NHS). For the samples marked Col, Col-DIIT and Col-EDC/NHS, dielectric properties were measured in the frequency range from 100 Hz to 100 kHz and temperatures from 25 to 145 degrees C. In the full temperature range, the average values of relative permittivity and dielectric losses for Col samples are lower than those recorded for Col-DHT and Col-EDC/NHS samples. The peak temperature of the dielectric parameters attributed to the denaturation temperature for Col, Col-DHT and Col-EDC/NHS, respectively, is about 75 degrees C, 83 degrees C and 89 degrees C. In addition, the values of these parameters are much higher in Col-EDC/NHS than in Col-DHT at the same temperature and frequency. The permittivity decrement and conductivity increment, respectively, for Col-EDC/NHS are about 62 and 32 times greater than those given by Col-DHT, which is a consequence of the EDC/NHS crosslinking action. Our electrical and dielectric studies of fish Col cross-linked by EDC/NHS or DHT provide deeper insight into the structure of collagen materials and help improve the synthesis of Col-based scaffolds for tissue engineering.