Restructuring the Interface of Silk–Polycaprolactone Biocomposites Using Rigid-Flexible Agents

Abstract

Natural fiber-reinforced biocomposites with excellent mechanical and biological properties have attractive prospects for internal medical devices. However, poor interfacial adhesion between natural silk fiber and the polymer matrix has been a disturbing issue for such applications. Herein, rigid-flexible agents, such as polydopamine (PDA) and epoxy soybean oil (ESO), were introduced to enhance the interfacial adhesion between Antheraea pernyi (Ap) silk and a common medical polymer, polycaprolactone (PCL). We compared two strategies of depositing PDA first (Ap− PDA−ESO) and grafting ESO first (Ap−ESO−PDA). The rigidflexible interfacial agents introduced multiple molecular interactions at the silk−PCL interface. The "Ap−PDA−ESO" strategy exhibited a greater enhancement in interfacial adhesion, and interfacial toughening mechanisms were proposed. This work sheds light on engineering strong and tough silk fiber-based biocomposites for biomedical applications.

Tough silk fibroin hydrogel via polypropylene glycol (PPG) blending for wearable sensors

“…Which leads to increased spacing and reduced crystalline regions in the composite hydrogel, resulting in a more flexible membrane. Moreover, the polar bonds between the silk fibrous molecular chains are disrupted, allowing the molecular chains to slide more easily, thereby increasing the plasticity of the hydrogel 31,32 . However, if the PPG content is further increased, the PPG molecules start to form clusters, separating from the silk fibrous structure.…”

“…Moreover, the polar bonds between the silk fibrous molecular chains are disrupted, allowing the molecular chains to slide more easily, thereby increasing the plasticity of the hydrogel. 31,32 However, if the PPG content is further increased, the PPG molecules start to form clusters, separating from the silk fibrous structure. This disrupts the uniform system and significantly decreases the mechanical properties.…”

Proteins for Applied and Functional Materials

“…In this regard, Zhao et al reported that incorporating polycaprolactone (PCL) into silk fibers can impact the interfacial adhesion of these biocomposites and result in properties relevant to future biomedical applications needing substrates with optimal adhesion. The high compatibility between the protein and the PCL was achieved by including natural additives such as epoxy soybean oil . The potential of altering the morphologies of protein systems by biomacromolecules was also tested by Niu et al, where carboxymethylcellulose was used to tailor the morphologies of colloidal particles from ovalbumin protein .…”