Applications and advances of hydrogels in bone tissue engineering repair related to sports injuries

Abstract

BACKGROUND: Hydrogel, as a highly biomimetic and modifiable biomaterial, shows a broad application prospect in the field of bone tissue engineering. OBJECTIVE: To review the current research status and development trend of hydrogel in bone tissue engineering. METHODS: The PubMed and CNKI databases were searched for articles on the application of hydrogels in bone tissue engineering. Chinese and English search terms were “hydrogel, bone tissue engineering, nanomaterials, bone regeneration mechanism, bone defect repair.” Based on the inclusion and exclusion criteria, 113 articles were included for review. RESULTS AND CONCLUSION: To improve how hydrogels work for bone tissue engineering, researchers have used different strategies to add new functions. These include changing their physical and chemical properties, adding biological components, and strengthening them with other materials. The goal is to make hydrogels more compatible with the body, stronger, able to break down at a controlled rate, and better at delivering drugs. Functionalized hydrogels help bones regenerate through several ways: by influencing how cells interact, regulating growth factors and signaling pathways, controlling mechanical signals and the surrounding environment, and acting as drug and nano-delivery systems. Future research on hydrogels will concentrate on building systems that combine multiple functions. For instance, by adding features that respond to temperature, pH, enzymes, or magnetic fields, the hydrogels can achieve spatiotemporally controlled release of bioactive factors or drugs, enhancing their dynamic intervention capability throughout the bone regeneration process. Developing polymer materials with biodegradability, tunable mechanical properties, and microenvironment adaptability will effectively improve their stability and tissue integration in complex physiological environments. With the aid of high-precision 3D printing technology, scaffolds with controlled structure, functional zoning, and personalized customization can be constructed to match the structural characteristics of individual patient defects.

1. Introduction

Bone tissue, as a dynamic load-bearing tissue, performs multiple physiological functions in the human body, including maintaining body shape, metabolic regulation, and organ protection. Additionally, bone tissue serves as a mineral reservoir, regulating mineral storage and release to maintain mineral homeostasis [1]. However, due to factors such as trauma, infection, tumor, and aging, bone tissue is prone to damage, severely affecting patients' quality of life [2]. Although bone tissue has a certain self-repair capacity, for large bone defects or complex bone injuries, relying solely on endogenous regeneration often fails to meet repair needs [3-6]. Therefore, effectively promoting bone regeneration has become an important research topic in clinical medicine and biomedical engineering.

Currently, treatment strategies for bone defects mainly include autologous bone grafting, allogeneic bone grafting, and xenogeneic bone grafting. Among these, autologous bone grafting is considered the 'gold standard' for bone defect repair due to its good histocompatibility and osteogenic capacity [7-8]. However, this method still has many limitations, such as donor site morbidity, shape mismatch, limited bone source, and postoperative complications [9]. Consequently, bone tissue engineering strategies based on biomaterials have emerged and gradually become an important direction for solving bone defect problems. In recent years, novel therapeutic methods represented by bone tissue engineering scaffolds, nano-drug delivery systems, and 3D printing technology have made significant progress, providing more promising solutions for bone repair [10].

In the field of bone tissue engineering, the extracellular matrix, as a complex biological macromolecular network, plays a crucial role in cell adhesion, proliferation, differentiation, and tissue remodeling [11]. Hydrogels, due to their highly biomimetic three-dimensional network structure, can mimic the microenvironment of the natural extracellular matrix, providing suitable growth scaffolds for cells, thereby promoting osteoblast differentiation and tissue regeneration. Therefore, hydrogels are considered one of the most promising biomaterials in bone tissue engineering [12-13].