• Dashtimoghadam, Erfan
• Vantankhah-Varnosfaderani, Mohammad
• Zhang, Daixuan
• Fahimipour, Farahnaz
• Sheyko, Sergey

Abstract

Soft-to-hard and hard-to-soft transition is universally adapted by living species as one of their survival strategies (e.g. defense mechanisms in echinoderms), as well as by various technologies (e.g. biomedical devices like orthopedic/dental casting). Adaptation of tissue implants both hard and soft shapes have distinct yet coexisting roles. To this end, it is required that the transition occurs at body temperature and modulus drops to a biological level of ~1-100 kPa. While adjusting the melting temperature typically involves variation of chemical composition, the modulus is limited by chain entanglements to >105 Pa. Herein we report a distinct methodology to enable a significant modulus drop 105-106 times from GPa to kPa utilizing crystallizable bottlebrush architecture. These single-component biocompatible hard-to-soft switchable materials have softness and transition temperature that can be individually tuned to match biological tissue mechanics. Specifically, we synthesized a series of bottlebrush networks based on polycaprolactone with various side-chain length and cross-link density. The synthesized networks were investigated for their mechanical and thermal properties using dynamic mechanical analysis and differential scanning calorimetry. Further, the efficiency of tissue-adaptive matrices fabricated into microneedle patches was investigated on release profile a model drug. The developed architecturally encoded design of synthetic biomaterials is readily expandable for other biocompatible and biodegradable polyesters.

Topics

• density
• impedance spectroscopy
• chemical composition
• differential scanning calorimetry
• casting
• biomaterials
• bottlebrush
• melting temperature
• dynamic mechanical analysis