Polydopamine Coatings in Bone Tissue Engineering

Polydopamine coatings have emerged as a transformative platform for the modification of bone tissue engineering scaffolds. Inspired by mussel adhesive proteins, the polymer forms a conformal layer on diverse substrates under mild conditions, introducing catechol and amine functionalities that enhance surface hydrophilicity, cell adhesion and further biofunctionalisation. By serving as a universal primer, polydopamine facilitates the immobilisation of osteogenic growth factors, peptides and minerals, while improving mechanical integration with native bone. Coatings can induce in situ biomineralisation of hydroxyapatite, regulate osteoblast and stem cell behaviour and modulate resorption by osteoclasts. These attributes make polydopamine a versatile tool to combine osteoinductive and osteoconductive properties, address challenges of implant integration and support the regeneration of critical-sized defects. Recent advances have clarified the mechanisms of mineral nucleation at the interface and demonstrated the efficacy of polydopamine‐functionalised constructs in promoting robust bone formation in vitro and in vivo.

Research from Nature Portfolio

Recent studies have elucidated how polydopamine acts as a priming layer to control mineral nucleation and strengthen the interface between implants and newly formed bone. One investigation revealed that on polydopamine‐coated polymeric substrates, calcium phosphate ions nucleate through a mixed “islanding” and planar growth mode, yielding a bonded interface with increased interfacial strength compared to uncoated surfaces. This finding provides mechanistic insight into how the catechol chemistry of polydopamine influences early biomineralisation pathways.

Further work has demonstrated that polydopamine–laced hydroxyapatite–collagen composites enhance the osteogenic response of bone marrow‐derived mesenchymal stem cells. The coated composite exhibited superior cell attachment, proliferation and mineral deposition in vitro, and when implanted into critical‐size calvarial defects, the material supported substantial new bone formation, particularly in the presence of seeded stem cell aggregates. These outcomes underscore the capacity of polydopamine to bolster both cellular and material factors critical for bone regeneration.

Research from all publishers

A multifunctional nanofibre system incorporated mussel‐inspired polydopamine to modify coaxially electrospun core–shell fibres loaded with alendronate and hydroxyapatite. The polydopamine layer improved scaffold wettability, mechanical strength and enabled sustained sequential release of therapeutic ions and drugs, leading to enhanced osteoblast function, reduced osteoclastogenesis and accelerated bone repair in animal models.

Another study explored the decoration of polydopamine‐functionalised alginate dialdehyde–gelatin scaffolds with milk protein coatings. Optimising protein concentration yielded improved swelling, biomineralisation and stability, while supporting mesenchymal stem cell adhesion, proliferation and osteogenic marker expression. This approach emphasises the synergy between polydopamine adhesion and secondary protein layers for subchondral bone regeneration.

Foundational research on biodegradable PLGA/hydroxyapatite scaffolds showed that a polydopamine coating can immobilise dual osteogenic factors (BMP-2 and IGF-1), achieving sustained release and markedly improving in vitro osteogenic differentiation and in vivo defect healing compared to unmodified constructs. This strategy highlights the versatility of the polydopamine layer for growth factor delivery.

Polydopamine Coatings in Bone Tissue Engineering publication trend

The graph below shows the total number of articles in polydopamine coatings in bone tissue engineering across all publications each year (not limited to Nature Index journals).

Technical terms

Polydopamine: A bioinspired polymer formed by dopamine self-polymerisation, used to functionalise surfaces via catechol chemistry.

Osteoinduction: The process by which progenitor cells are stimulated to differentiate into osteoblasts, initiating new bone formation.

Osteoconduction: Provision of a scaffold or surface that supports the attachment and guidance of new bone growth along its structure.

Biomineralization: The biologically mediated formation of inorganic minerals, such as hydroxyapatite, on or within organic matrices.

Hydroxyapatite: A calcium phosphate mineral that constitutes the primary inorganic component of bone and provides mechanical strength.

Simulated body fluid: An aqueous solution containing ion concentrations similar to human plasma, used to assess mineral deposition on biomaterials.

References

1. Bioinspired core-shell nanofiber drug-delivery system modulates osteogenic and osteoclast activity for bone tissue regeneration. Materials Today Bio (2024).
2. Architecture of β-lactoglobulin coating modulates bioinspired alginate dialdehyde-gelatine/polydopamine scaffolds for subchondral bone regeneration. Acta Biomaterialia (2024).
3. Improving osteogenesis of PLGA/HA porous scaffolds based on dual delivery of BMP-2 and IGF-1 via a polydopamine coating. RSC Advances (2017).
4. Strategies for Using Polydopamine to Induce Biomineralization of Hydroxyapatite on Implant Materials for Bone Tissue Engineering. International Journal of Molecular Sciences (2020).
5. Polydopamine-Laced Biomimetic Material Stimulation of Bone Marrow Derived Mesenchymal Stem Cells to Promote Osteogenic Effects. Scientific Reports (2017).
6. Effects of polydopamine coatings on nucleation modes of surface mineralization from simulated body fluid. Scientific Reports (2020).