Abstract
Thermoresponsive bio-only gels that yield sufficiently large strokes reversibly and without large hysteresis at a well-defined temperature in the physiological range, promise to be of value in biomedical application. Within the present work we demonstrate that electron beam modification of a blend of natural collagen and elastin gels is a route to achieve this goal, viz. to synthesize a bioresorbable gel with largely reversible volume contractions as large as 90% upon traversing a transition temperature that can be preadjusted between 36 °C and 43 °C by the applied electron dose. Employing circular dichroism and temperature depending confocal laser scanning microscopy measurements, we furthermore unravel the mechanisms underlying this macroscopic behavior on a molecular and network level, respectively and suggest a stringent picture to account for the experimental observations.
Highlights
Our circular dichroism (CD) measurements indicate a gradual change in elastin structure due to heating, which is in line with a gradual decrease of the radius of gyration reported for elastin-like polymers with increasing temperature in previous studies[19] and presently results in build-up of an increasing compressive stress on the network backbone
In contrast to well-established tensile loading[20], the network backbone is susceptible to Euler buckling under compressive loading, leading to network collapse once a critical load is exceeded[21]
We propose that the observed sharp contraction transition occurs exactly at the point, where the elastin-generated stresses equal the critical load σcrit of the network backbone
Summary
After irradiation of the solution with 60 kGy the secondary structure of the protein changes as indicated by decrease and shift of the negative Cotton effect from 203 nm to 197 nm and the loss of the band at 222 nm. The alpha-helical structure of elastin is lost after irradiation and changes the protein to random coil This feature of partial protein denaturation by electron beam treatment has been found in the case of egg white protein at 16 kGy18. Electron beam treatment successively shifts the peak from 200 nm to 197 nm which coincides with disappearance of the plateau region This leads to the conclusion that irradiation increases the amount of coil structures and decreases the alpha-helical content as detected before for elastin. The same holds true for the triple-helix of collagen whereas the random coil structure contribution is temperature insensitive as well as little affected by irradiation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
