Shanghai Ninth People's Hospital Announces New Patent for Orthopedic Tissue Engineering Material

On February 6, 2024, a patent titled “Preparation Method and Application of Strontium-Doped Calcium Silicate-Silk Fibroin Composite Material” was publicly disclosed for the first time by Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine. This patent utilizes strontium-doped calcium silicate-silk fibroin composite as a scaffold structure, holding promise to provide a more ideal scaffold material for the rapid functional repair of bone defects.

Patent Timeline, sourced from Patsnap

This patent originates from the National Natural Science Foundation of China General Program project, “Research on Strontium-Doped Calcium Silicate/Silk Fibroin Scaffolds Loaded with Adipose-Derived Stem Cells to Promote Functional Reconstruction of Jaw Defects,” which was conducted from January 2015 to December 2018 under the leadership of Dr. Xu Yuanjin, Chief Physician in the Department of Oral and Maxillofacial Surgery at Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, and his team.

Bone tissue engineering is a scientific field dedicated to developing materials capable of repairing or replacing human bone tissue using biological and engineering approaches. With breakthroughs in materials science, medicine, and biology, there are increasingly higher demands for orthopedic tissue repair. Consequently, bio-based materials that exhibit superior biocompatibility and functionality, and that can promote bone tissue regeneration, have become a focal point of research in bone tissue engineering.

These materials are mainly divided into several major categories, namely those based on metal modification.Biomaterials, Bioceramic Materials, Polymer Materials, and Composite Materials。

Metallic materials were among the first to be applied in bone repair and regeneration due to their favorable mechanical properties. Among these, titanium alloys have been widely used because of their excellent mechanical performance and biocompatibility. The team led by Liu Zhongjun at Peking University Third Hospital employed customized 3D-printed porous titanium alloy implants for the repair of large segmental bone defects, achieving early restoration of limb function and reliable long-term integration at the “implant-bone” interface, thereby significantly improving therapeutic outcomes.

Ceramic materials exhibit excellent stability. Academician Zhang Xingdong of Sichuan University discovered and confirmed that non-living porous calcium phosphate ceramics can induce bone regeneration, a function typically characteristic of bioactive substances. He proposed the concept of "osteoinductive biomaterials." When calcium phosphate bioceramics are implanted into the human body, they gradually degrade over time and are replaced by new bone tissue. This process elicits no foreign body reaction and enables permanent rehabilitation.

Polymer materials include natural polymers such as collagen, hyaluronic acid, and chitosan, as well as synthetic polymers such as polymethyl methacrylate and polyurethane. The team led by Academician Zhang Xingdong of Sichuan University reported in Science Advances that biomimetic polyetherketoneketone materials can induce bone regeneration.

Composite materials are formed by combining inorganic materials with polymers. Among these, hydroxyapatite/chitosan composites represent a highly promising class of biomaterials, exhibiting excellent comprehensive mechanical and biological properties. Wang Fei et al., in their study published in *Chinese Journal of Tissue Engineering Research*, fabricated a ternary composite of nano-hydroxyapatite/chitosan/polylactide using the particle leaching method. The study demonstrated that its compressive strength closely matched that of human cancellous bone, and it showed the highest levels of alkaline phosphatase activity and osteocalcin expression in assays inducing osteogenic differentiation.

Of course, the scope of biomaterials extends far beyond bone tissue engineering.In recent years, biomaterials have gained increasing prominence in fields such as anti-aging and tissue engineering. Their superior properties and versatile capabilities have demonstrated diverse application potential in clinical treatment and disease research.。

For example, in the anti-aging medical aesthetics sector, Professor Robert Langer from the Massachusetts Institute of Technology (MIT) reported on a silicone polymer known as XPL in *Nature Materials* in 2017. Human clinical studies revealed that this material can eliminate under-eye bags, possesses strong moisturizing capabilities, provides protection against ultraviolet (UV) radiation, and is water-resistant. This material serves as a “second skin” for humans.

In the field of regenerative tissue engineering, Professor David J. Mooney of Harvard University simulates the natural extracellular matrix using materials such as hydrogels to promote in vivo tissue and organ regeneration and targeted destruction. In 2018, the team published a paper in PNAS, employing a 3D cell culture system that allows independent control over matrix stiffness, stress relaxation, and adhesive ligand density, thereby systematically exploring transcriptional programs influenced by different combinations of biophysical parameters via RNA-seq.

In the field of drug delivery, Professor Younan Xia of the Georgia Institute of Technology in the United States has designed and prepared a novel nanocarrier material with excellent biocompatibility and temperature-controlled repeatability. When loaded with doxorubicin (DOX) and IR780, both in vitro and cellular experiments achieved the desired outcomes: rapid drug release in response to near-infrared irradiation, thereby rapidly killing tumor cells.

From the perspective of technological research, research institutes and teams both domestically and internationally have pursued diverse directions in the study of biomedical materials, applying them across various fields of clinical medicine. Related research continues to be a hotspot and frontier in the international biomedical sector.