As the primary site for the biotransformation of drugs, the liver is the most focused on organ type in pharmaceutical research. However, despite being widely used in pharmaceutical research, animal models have inherent species differences, while two-dimensional (2D) liver cell monocultures or co-cultures and three-dimensional (3D) liver cell monoculture in vitro liver models do not sufficiently represent the complexity of the human liver’s structure and function, making the evaluation results from these tools less reliable. Therefore, there is a pressing need to develop more representative in vitro liver models for pharmaceutical research. Fortunately, an exciting new development in recent years has been the emergence of 3D liver cell co-culture models. These models hold great promise as in vitro pharmaceutical research tools, because they can reproduce liver structure and function more practically. This review begins by explaining the structure and main cell composition of the liver, before introducing the potential advantages of 3D cell co-culture liver models for pharmaceutical research. We also discuss the main sources of hepatocytes and the 3D cell co-culture methods used in constructing these models. In addition, we explore the applications of 3D cell co-culture liver models with different functional states and suggest prospects for their further development.

Large bone defects resulting from trauma, infection and tumors are usually difficult for the body’s repair mechanisms to heal spontaneously. Generally, various types of bones and orthopedic implants are adopted to enhance bone repair and regeneration in the clinic. Due to the limitations of traditional treatments, bone defect repair is still a compelling challenge for orthopedic surgeons. In recent years, bone tissue engineering has become a potential option for bone repair and regeneration. Amidst the various scaffolds for bone tissue engineering applications, hydrogels are considered a new type of non-toxic, non-irritating and biocompatible materials, which are widely used in the biomedicine field currently. Some studies have demonstrated that hydrogels can provide a three-dimensional network structure similar to a natural extracellular matrix for tissue regeneration and can be used to transport cells, biofactors, nutrients and drugs. Therefore, hydrogels may have the potential to be multifunctional sustained-release drug carriers in the treatment of bone defects. The recent applications of different types of hydrogels in bone defect repair were briefly reviewed in this paper.

Ion-complementary self-assembling peptides have been studied in many fields for their distinct advantages, mainly due to their self-assembly properties. However, their shortcomings, such as insufficient specific activity and poor mechanical properties, also limited their application. For the better and wider application of these promising biomaterials, ion-complementary self-assembling peptides can be modified with their self-assembly properties not being destroyed to the greatest extent. The modification strategies were reviewed by taking RADA16-I as an example. For insufficient specific activity, RADA16-I can be structurally modified with active motifs derived from the active domain of the extracellular matrix or other related active factors. For weak mechanical properties, materials with strong mechanical properties or that can undergo chemical crosslinking were used to mix with RADA16-I to enhance the mechanical properties of RADA16-I. To improve the performance of RADA16-I as drug carriers, appropriate adjustment of the RADA16-I sequence and/or modification of the RADA16-I-related delivery system with polymer materials or specific molecules can be considered to achieve sustained and controlled release of specific drugs or active factors. The modification strategies reviewed in this paper may provide some references for further basic research and clinical application of ion-complementary self-assembling peptides and their derivatives.

In recent years, hydrogels have emerged as promising candidates for bone defect repair due to their excellent biocompatibility, high porosity, and water-retentive properties. However, conventional hydrogels face significant challenges in clinical translation, including brittleness, low mechanical strength, and poorly controlled drug degradation rates. To address these limitations, as a multifunctional polymer, polydopamine (PDA) has shown great potential in both bone regeneration and drug delivery systems. Its robust adhesive properties, biocompatibility, and responsiveness to photothermal stimulation make it an ideal candidate for enhancing hydrogel performance. Integrating PDA into conventional hydrogels not only improves their mechanical properties but also creates an environment conducive to cell adhesion, proliferation, and differentiation, thereby promoting bone defect repair. Moreover, PDA facilitates controlled drug release, offering a promising approach to optimizing treatment outcomes. This paper first explores the mechanisms through which PDA promotes bone regeneration, laying the foundation for its clinical translation. Additionally, it discusses the application of PDA-based nanocomposite hydrogels as advanced drug delivery systems for bone defect repair, providing valuable insights for both research and clinical translation.

Ion-complementary self-assembling peptides have been studied in many fields for their distinct advantages mainly due to their self-assembly properties. However, their shortcomings, such as insufficient specific activity and poor mechanical properties, also limited their application. For better and wider application of this kind of promising biomaterials, ion-complementary self-assembling peptides can be modified with their self-assembly properties not being destroyed to the greatest extent. The modification strategies were reviewed by taking RADA16-Ⅰ as an example. For the insufficient specific activity, RADA16-Ⅰ can be structurally modified with active motifs derived from the active domain of the extracellular matrix or other related active factors. For weak mechanical properties, materials with strong mechanical properties or materials that can undergo chemical crosslinking were used to mix with RADA16-Ⅰto enhance the mechanical properties of RADA16-Ⅰ. To improve the performance of RADA16-Ⅰ as drug carriers, appropriate adjustment of the RADA16-Ⅰ sequence and/ or modification of the RADA16-Ⅰ-related delivery system with polymer materials or specific molecules can be considered to achieve sustained and controlled release of specific drugs or active factors. The modification strategies reviewed in this paper may provide some references for the further basic research and clinical application of ion-complementary self-assembling peptides and their derivatives.