A research team from the University of Virginia in the United States has pioneered a new type of 3D printing material. This material is compatible with the human immune system and is expected to promote the rapid and safe development of many medical technologies such as artificial organ transplantation and drug delivery. This breakthrough achievement was published in the latest issue of the journal Advanced Materials. The research team demonstrated a method to alter the properties of polyethylene glycol (PEG) and create a stretchable network structure. PEG has been widely used in biomedical technologies such as tissue engineering, but the traditional production method (removing water after crosslinking PEG polymers in water) can lead to structural fragility, crystallization, and inability to maintain integrity during stretching. To solve this problem, the team drew inspiration from the molecular design of manufacturing elastic rubber and adopted a "foldable bottle brush" structure, making the material both strong and highly elastic. Polymer molecules have many flexible side chains radiating from the central skeleton, which can fold like an accordion, storing additional length that can be unfolded, thereby achieving high stretchability. They applied the concept of folded bottle brush polymer to PEG. By exposing the precursor mixture to ultraviolet light for a few seconds, they started polymerization to form a bottle brush structure network, and successfully produced 3D printable, highly stretchable PEG based hydrogels and solvent-free elastomers. Team members stated that by changing the shape of the ultraviolet lamp, many complex structures can be created, providing new possibilities for the future manufacture of artificial organs or drug delivery systems. In addition, experiments have shown that this stretchable 3D printed PEG material is biocompatible, and cell culture tests have confirmed its compatibility with biological tissues, making it suitable for in vivo materials such as organ scaffolds. Looking ahead, this material may be combined with other materials to manufacture 3D printed products with different chemical compositions, which can expand multiple applications. For example, compared to existing solid polymer electrolytes, the new material exhibits higher conductivity and stretchability at room temperature, highlighting its potential as a high-performance solid electrolyte in advanced battery technology. The team stated that they will continue to explore its application prospects in solid-state battery technology. 3D printed biomaterials bring new changes to the field of regenerative medicine such as artificial organ transplantation. At the same time, related technologies are also facing the challenge of how to make 3D printed structures more compatible with the human immune system. Traditional artificial implants may cause rejection reactions or chronic inflammation in the human body. The new 3D printed biomaterials attempt to solve this problem at its root through precise molecular regulation and design. By using this method, 3D printed structures such as bones, cartilage, and even vascular tissue are expected to be truly accepted and integrated by the human body, opening up a new path for highly personalized regenerative medicine treatments. (New Society)