NIR Photothermal‐Responsive Shape Memory Polyurethane with Protein‐Inspired Aggregated Chymotrypsin‐Sensitive Degradable Domains

Abstract

Biodegradable shape memory polymers are promising biomaterials for stents used in minimally invasive surgical procedures such as intestinal stents. Herein, a series of biodegradable shape memory polyurethanes (SMPUs) containing a novel phenylalanine‐derived chain extender (PHP) are synthesized. Inspired by the fact that the function of biomacromolecules such as proteins is rich and varied because of the multiple combinations of the amino acid in highly evolved biosystems, this study finds that the sequence distribution of PHP in SMPU will also have a great influence on the phase structure and degradation behavior, especially the difference of surface morphology caused by degradation. Considering that the transition temperature (Ttrans) of SMPU obtained is higher than physiological temperature, oxidized carbon black (OCB) with the ability of photothermal conversion is introduced into SMPU, which can not only endow SMPU with near‐infrared response shape recovery characteristics, but also enhance phase separation degree and mechanical properties of them. SMPU/OCB composites show excellent shape memory effect and rapid photothermal response, and they can be degraded by chymotrypsin with an adjustable degradation rate. These SMPU/OCB composites show broad potential for application as intestinal stents.

NIR-induced photothermal-responsive shape memory polyurethane for versatile smart material applications

“…13). 43 The carbon black was introduced into the SMPU to provide photothermal-induced shape recovery properties to the PU. In order to enhance the compatibility between SMPU and carbon black, the surface of carbon black was oxidized to increase the carboxyl content, which was conducive to the dispersion of carbon black in SMPU solution in the DMF and SMPU membrane matrix.…”

“…81 Herein, Yang et al (2022) reported a biodegradable PU with NIR light-induced photothermal responsive shape memory property, as a potential implantable material for intestinal stents. 43 A novel chain extender phenylalanine (PHP) derivative with two chymotrypsin cleavage sites was first synthesized. 82 The SMPU was prepared by reacting HDI, PCL-4000 diol, PHP chain extender, and oxidized carbon black (OCB) as photothermal agent (Fig.…”

“…Meanwhile, OCB also acted as a filler distributed uniformly in SMPU, which restricted the movement of the chain segments and increased the T g of the soft segments. 43,83 The T g is a critical parameter that influences various aspects of material performances in biomedical devices, such as mechanical properties, shape memory performance, and processing conditions.…”

Shape memory polyurethane potentially used for vascular stents with water-induced stiffening and improved hemocompatibility

“…2 Due to the good biocompatibility and designability of their chemical structure, shape memory polyurethanes (SMPUs) have potential applications in biomedical devices, especially self-expanding vascular stents. [3][4][5][6][7][8] However, vascular stents made of SMPs or SMPUs are generally confronted with a significant reduction in radial support after shape recovery and are even insufficient to support the narrow parts. 9 When used in vivo, the switching phases of SMPUs are always stiff below the transition temperature (T trans ) but they become flexible to facilitate the shape recovery accompanied by the reduction of stiffness when heated to reach the T trans , 10 and the modulus is dramatically declined in a 37 1C aqueous environment due to the strong plasticization of water.…”