In-house Development of Smart Materials for 4D Printing

Three-dimensional (3D) bioprinting is a versatile technique for biomedical applications, and includes organ printing, 3D disease model development, and drug delivery. The bioprintable materials combined with live cells have been utilized as bioinks in 3D bioprinter to fabricate versatile 3D printed structures. The 3D structures developed with smart and responsive materials can change their dimension, a technique similar to self-assembly, unfolding a new branch termed as four-dimensional (4D) printing. This manuscript reviews the details of various bioprintable materials and 3D printers, the application of 3D printing in biomedicine, smart materials, and stimulations for 4D printing. Further, this article also summarizes the regulatory issues and the limitations involved with the bioprinting. The advancements in 3D and 4D printing technology have significantly contributed to the medical field, and adequate research and amalgamation of engineering and science ideas will strengthen the application of this technology and bring solution for the existing problems.Graphical abstract

3D printing technology has revolutionized the way products are manufactured, and it has opened up new possibilities in the field of smart materials. Smart materials are materials that can change their properties in response to external stimuli, such as temperature, pressure, or light. By combining 3D printing technology with smart materials, highly customizable and responsive products are created. The addition of the time dimension to 3D printing has introduced 4D printing technology, which has gained considerable attention in different fields such as medical, art, and engineering. To bridge the gap in knowledge of 4D, this paper assessed the revolution in healthcare with 3D/4D printing and smart materials. Data was generated as part of a broader empirical study which sought to explore healthcare personnel and electrical engineers’ perception on the practices around the use of 3D/4D printing technology and smart materials. The main method used was structured interviews. 12 participant were purposively selected and interviewed including healthcare personnel and electrical engineers form Philippines and Nigeria. The findings reveal an array of activities undertaken using both 3D and 4D. Furthermore, the study revealed that 4D printing is a new generation of 3D printing. Another aspect of the 3D usage is the integration of electrical stimulation and smart implant as a new area of study in healthcare. 3D could also be used to monitoring the smart implant performance. The study also evaluate the possibility of using Internet of things (IoT) in the smart implant as some device embeds smart materials. Smart implant commonly used includes orthopedic applications, such as knee and hip replacement, spine fusion, and fracture fixation. The smart materials used in this technology are important because 3D printing allows printed structures to be dynamic. The paper highpoints is that 4D printing has great potential for the future.

4D printing: Pragmatic progression in biofabrication

Every industry need helps to modify its working style quickly with the improvement of existing technology. New developing technologies improve production speed, reduce industrial process costs, etc. Technical specialists carry out continuous research and development to increase efficiency. A significant advance in 4D printing over 3D Printing is its capacity to alter shape over time because external elements such as pressure, air, heat, water, etc., use controlled impact. 4D Printing has one “D" instead of 3D Printing, and the fourth aspect is time. Therefore, its capacity to alter shape over time is a significant advancement of 4D printing over 3D printing technologies. It is evident that 4D printing will be of tremendous value to manufacturers regarding features and advances in dentistry. Its applications cover medical modelling, surgical guides manufacture, prosthodontics, dentistry, orthodontics, implantology, and dentistry instruments. This paper is brief about 4D printing and its printing of smart materials through 4D printing. Process workflow and Bio-Oriented 4D printable smart materials for dentistry are presented diagrammatically. Further, the paper identifies and discusses the significant potential of 4D printing for dentistry. 4D printing is an innovative technology that uses the inputs from smart materials, and the 3D printed item becomes another structure via the impact of external energy sources such as temperature, light, or other environmental stimuli. The objective is to integrate technology and design to create self-assembly and programmable material technologies that better design, production, and performance.

Transverse mechanical stress and optical birefringence induced into single-mode optical fibre embedded in a smart polymer composite material

The area of 4D printing is a revolutionary one that emerged from the integration of additive manufacturing and polymer science. In this area, materials can change dynamically in response to external stimuli. Complex structures with developing, shape-morphing, and adaptive behaviors can be created by integrating innovative 3D printing technology with intelligent materials, which are naturally sensitive to environmental cues. Polymer chemistry determines these smart materials and discusses the design concepts that control their responsiveness. A particular focus is on incorporating stimuli-responsive polymers, like hydrogels and shape memory polymers, into the 4D printing process. These ensuing structures suggest programmable behavior in response to light, humidity, and temperature variations in the environment. 4D printing has been designated a revolutionary technology with significant implications for sectors looking for dynamic, responsive, and personalized solutions. The study of polymer-based innovative materials in 4D printing presents novel prospects for ingenuity, presenting extraordinary chances for creating and producing materials with dynamic properties. The future of advanced manufacturing is being shaped by this research, which advances our fundamental understanding of intelligent materials and opens up novel applications in various fields.

4D printing applications in medical field: A brief review

Four-dimensional (4D) printing, an evolution of additive manufacturing (AM), integrates stimuli-responsive materials like thermal-induced shape memory polymers (TSMPs) to enable programmable, time-dependent transformations in structures. This review systematically examines recent advancements in TSMPs, 4D printing technologies, and fabrication strategies, emphasizing their interdisciplinary convergence and applications. TSMPs, with their unique phase-separated microstructures, modulus disparity, and tailorable recovery behaviors, form the foundation of 4D-printed systems, enabling innovations in aerospace, healthcare, and soft robotics [1–3, 33–45]. Key printing methods—including fused deposition modeling (FDM), direct ink writing (DIW), PolyJet, stereolithography (SLA), and digital light processing (DLP)—are analyzed for their strengths and limitations. FDM dominates due to cost-effectiveness but faces challenges in resolution and anisotropy [88, 91–93], while SLA and DLP offer high precision and speed but require material optimization [105, 111–115]. Advanced fabrication strategies, such as localized TSMP printing, composite reinforcement with carbon nanotubes or Fe 3O 4 particles, and sacrificial mold templating, expand design possibilities for multi-functional and multi-scale structures [117–120, 140–144]. Despite progress, challenges persist, including environmental sensitivity of TSMPs, interlayer bonding in AM, and dynamic modeling of non-equilibrium thermal responses [74, 77, 146]. Future directions focus on multi-responsive materials, machine learning-driven constitutive models, and sustainable bio-based formulations to address scalability and cyclic durability [31, 77, 147–149]. By bridging material science, computational modeling, and advanced manufacturing, this work provides a roadmap for harnessing 4D-printed TSMPs in real-world applications, from self-deploying biomedical devices to adaptive aerospace systems [28, 85, 137].

4D printing is a pioneer field to produce functional smart devices. The combination of 3D printing and smart material is called as 4D printing. The extra dimension refers to time in order to shape transformation of the printed part during time. FDM is a universal process to 3D printing of thermoplastic polymers. Therefore, for successful and typical 4D printing a deep understanding of every aspect of shape memory polymers especially thermoplastic polymers is necessary. So, in this chapter, shape memory polymers, printing preparation such as filament production and FDM printing parameters, finally applications, previous finding and functional printed parts by FDM have been studied detailed.

PurposeAdditive manufacturing has rapidly developed in terms of technology and its application in various types of industries. With this rapid development, there has been significant research in the area of materials. This has led to the invention of Smart Materials (SMs). The 4D printing is basically 3D printing of these SMs. This paper aims to focus on novel materials and their useful application in various industries using the technology of 4D printing.Design/methodology/approachResearch studies in 4D printing have increased since the time when this idea was first introduced in the year 2013. The present research study will deeply focus on the introduction to 4D printing, types of SMs and its application based on the various types of stimulus. The application of each type of SM has been explained along with its functioning with respect to the stimulus.FindingsSMs have multiple functional applications pertaining to appropriate industries. The 4D printed parts have a distinctive capability to change its shape and self-assembly to carry out a specific function according to the requirement. Afterward, the fabricated part can recover to its 3D printed “memorized” shape once it is triggered by the stimulus.Originality/valueThe present study highlights the various capabilities of SMs, which is used as a raw material in 4D printing.Graphical abstract

The latest advances in additive manufacturing methods (AMM) generally called as three-dimensional (3D) printing has been permitted to design and generate complicated profiles which are not possible with conventional techniques. A new method of creation of an object by layer by layer called it as rapid prototyping technique which is also known as three-dimensional printing. If these methods of printing supposed to be implemented for self-healing smart materials, then it is known as four-dimensional printing. Also, day-to-day advancements in fashion in the lifestyle of public, industries are not capable to satisfy their requirements with conventional manufacturing techniques with conventional materials because of increased cost to alter the design, manufacture and process layout for each fashion style. It is impossible to satisfy with conventional materials as well as processing methods so more competition existed in the present industrial sectors according to market demands as per customer requirements. Advancements in additive manufacturing techniques covered this gap by day-to-day developments in materials and their methods. In this review article, discussed about recent developments of smart materials, innovations in 4D printing and challenges which are faced in the research and development (R&D) divisions, also described about variety of application areas almost in all fields. This paper provides the basic information to the young researchers who are interested in this area.KeywordsRapid prototyping4D printingSelf-healing smart materialsTemperature responsive materialsLight/electric current/magnetic field materials

Additive manufacturing is initially developed to meet the needs in the field of aerospace engineering. As the cost of sending a component into the space to replace the failed part is more than the actual cost of the product the researchers started working on printing machines. This effort of the researchers and research organization bought a 3D printing machine into the picture. Taking the 3D model as reference, the 3D printing machine prints the component by adding the material in layers. Later, the application of 3D printing was extended in many fields like medicine, automobile, and textile industry. Taking a step forward, a private research organization in Cambridge, Massachusetts institute of technology (MIT), has developed a 4D printing machine in 2013. 4D printing is printing a 3D component with smart material to add a fourth dimension called intelligence. Hence, this gave rise to programmable printing. This paper deals with 4D printing technology, materials suitable for printing the component, materials that add strength to the component, applications, challenges, and future scope.

Design for 4D printing: A voxel-based modeling and simulation of smart materials

The advancement of four-dimensional (4D) printing has been fueled by the rise in demand for additive manufacturing and the expansion in shape-memory materials. The printing of smart substances that respond to external stimuli is known as 4D printing. 4D printing allows highly controlled shapes to simulate the physiological milieu by adding time dimensions. The 4D printing is suitable with current progress in smart compounds, printers, and its mechanism of action. The 4D printing paradigm, a revolutionary enhancement of 3D printing, was anticipated by various engineering disciplines. Tissue engineering, medicinal, consumer items, aerospace, and organ engineering use 4D printing technology. The current review mainly focuses on the basics of 4D printing and the methods used therein. It also discusses the time-dependent behavior of stimulus-sensitive compounds, which are widely used in 4D printing. In addition, this review highlights material aspects, specifically related to shape-memory polymers, stimuli-responsive materials (classified as physical, chemical, and biological), and modified materials, the backbone of 4D printing technology. Finally, potential applications of 4D printing in the biomedical sector are also discussed with challenges and future perspectives.

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