composites, photothermal nanollers that may be metallic, polymeric, or carbona­ceous are incorporated in the matrices of SMPs. Metallic nanoparticles generate heat from incident photons (light energy) through the surface plasmonic effect, while polymeric and composite materials exhibit photothermal capabilities due to their strong light absorption [25]. Usually, the light-induced heating is rapid and non-equilibrium in nature. Some common examples of metallic nanostructures include gold nanoparticles (AuNPs), nanorods (AuNRs), and silver nanoparticles (Ag NPs). SMPs such as Poly(ethylene oxide)(PEO) [26], poly(vinyl alcohol) (PVA) [27], and polyurethane [28] are reported as matrices in combination with metallic nanollers such as AuNPs and AuNRs to yield light-responsive SMP com­posites. The visible and NIR regions of the light wavelengths (530, 532, 785, 805, and 860 nm) have mostly been used owing to their benign nature and relatively deeper tissue penetration capabilities [27]. The laser power densities and nanoller content inuence the shape recovery efciency of the SMP composite. This, in turn, allows for precise spatial and temporal control of the entire process, which is bene­cial for biomedical applications.

Given the shortcomings of conventional treatments in meeting patient require­ments, the need for enhanced tissue and organ substitutes is pressing. Tissue engi­neering seeks to produce biomedical scaffolds with diverse functionalities, potentially offering effective solutions. Engineered materials’ ability to change shape holds signicant promise in tissue engineering, as it can facilitate less inva­sive surgical procedures, smooth integration, and replication of the dynamic mor­phologies of natural tissues and organs [40–48]. In Fig. 11.4, the hydrogels changing shapes in an aqueous solution is shown. In cardiac tissue engineering, replicating the intricate architecture of natural tissues is crucial for successful regeneration. Mimicking native cellular environments through biomimetic topo­graphical cues enhances tissue and organ regeneration. Proper alignment of cardio­myocytes is essential for effective mechanical and electrical activation of the heart’s ventricles in cardiac tissue engineering. However, producing complex bio­mimetic tissue scaffolds with integrated topographical cues remains challenging. A possible remedy is provided by materials that can alter shape, allowing for creating dynamic scaffolds with distinctive micropatterns and architectures [44, 49–55]. For instance, Zhang etal. utilized smart natural lipids, such as soybean oil epoxidized acrylate, to create biocompatible, 4D-dynamic shape-changing tissue scaffolds. These thin lm scaffolds, less than 300μm thick, are bent or self-assembled into rolling structures upon external stimulation (e.g., immersion in ethanol for 10min). Human mesenchymal stem cells (hMSCs) were successfully regulated in their behavior by this method, which offered stable surface structures across a wide region, biocompatibility, and excellent integration. hMSCs were able to proliferate along the created micropatterns and form continuous cellular sheets because of the scaffolds’exceptional cell compatibility. Further evidence of these printed scaffolds’high potential for cardiac tissue engineering applications comes from the dramatically elevated marker expression during the cardiomyogenic differentiation of hMSCs. Osteoprogenitor migration, proliferation, differentiation, and extracel­lular matrix (ECM) production are among the dynamic processes involved in bone tissue engineering. Scientists have investigated synthetic and biodegradable shape­memory polymer (SMP) scaffolds for this purpose, which show potential for mini­mally invasive surgical procedures. By using their ability to change shape, these scaffolds may be compressed and placed at the location of a defect to allow for less intrusive operations. Later, they could be activated to expand and regain their previ­ous shape. Furthermore, by better conforming to the uneven boundaries of bone defects, these scaffolds’ shape- memory capabilities offer advantages in bone tissue engineering.