From passive engineering to immune dialogue: a new regenerative paradigm

In reconstructive and periodontal surgery, the success of regeneration has long been attributed solely to the stimulation of intrinsic cellular programs, such as osteoblastogenesis. However, the persistence of peri-implant inflammation or fibrosis serves as a reminder of a clinical reality: the immune microenvironment orchestrates tissue destiny. The problem addressed by this editorial is the obsolescence of so-called "immune silence" strategies, where biomaterials are designed to be merely inert, thus neglecting the essential dynamic dialogue between immune cells and tissue progenitors.

This article summarises major advances published in August 2026, aiming to validate the transition towards active modulation of the immune niche. The objective is to demonstrate that clinical success now depends on the ability of substitutes to actively engage the host's immune system rather than ignoring it. The central hypothesis is based on the fact that tissue regeneration (bone, periodontal, or cardiac) can be optimised by transforming the biomaterial into a dynamic regulator. The latter must be capable of steering macrophage polarisation, controlling the spatiotemporal release of bioactive ions, and modulating metabolic interactions. For the practitioner, this paradigm shift requires considering each substitute no longer as a passive support, but as an agent capable of dictating the local immune response to promote healing.

Methodological approach to the research theme

This editorial synthesizes the methodologies of four major scientific contributions (volume 14, 2026) focused on the modulation of the immune environment for tissue regeneration. The corpus is divided into two experimental studies and two systematic/conceptual reviews.

• Biomaterial engineering (Liu et al.): Experimental design using polycaprolactone (PCL) nanofiber scaffolds. The protocol integrates polydopamine (PDA) and copper ions to evaluate a synergistic antibacterial and osteogenic strategy based on controlled ion release and recovery.
• Integrated analysis and bioinformatics (Zhao et al.): Study combining bioinformatics analyses with experimental validation to identify genes linked to cell-in-cell (CIC) interactions and immune heterogeneity (immunosuppressive vs. immuno-activated subtypes).
• Review articles (Zhao et al. ; Wang et al.): Systematic and conceptual reviews of the literature on osteoimmunology and cementum regeneration. The authors analyzed the mechanisms of macrophage polarization, bioactive ion release, metabolic reprogramming, and epigenetic modifications.

All of this work is based on a multidisciplinary approach coupling developmental biology, single-cell analysis and experimental validation of interactions between immune cells and specific tissue progenitors.

Results: Towards active modulation of regenerative immunology

This collection of works, synthesizing four major contributions, marks a departure from conventional regeneration strategies. The data presented validate the transition from a concept of "immune silence" to one of active "immune dialogue" between the biomaterial and the host.

1. Biomaterials engineering and ionic control (Liu et al.)

The experimental study on polycaprolactone (PCL) nanofiber scaffolds integrating polydopamine (PDA) and copper ions demonstrated a capacity for controlled ion release and recovery. This system maintains the copper concentration within an optimal therapeutic window, resolving the usual compromise between:

• Antibacterial activity: Effective against pathogens without inducing systemic cytotoxicity.
• Osteogenic promotion: Demonstrated synergy between the scaffold structure and ionic release to promote bone formation.

2. Immune typology and heart failure (Zhao et al.)

Through bioinformatic analysis coupled with experimental validation, the authors identified genes linked to "cell-in-cell" (CIC) interactions as regulators of immune heterogeneity. The results allow for the classification of pathological profiles into two distinct subtypes:

3. Periodontal regeneration and reprogramming (Wang et al.)

The review of cementum regeneration mechanisms highlights the importance of metabolic reprogramming and epigenetic modifications. The authors report that the success of periodontal regeneration depends on manipulating the interactions between stem cells and immune cells, rather than simple stimulation of cementoblastic lineages. Micro-environmental signals act as critical levers to overcome the limitations of traditional therapies.

4. Paradigm shift in bone substitutes (Zhao et al.)

The synthesis of bone substitute modification strategies confirms the efficacy of macrophage polarization. By controlling the release of bioactive ions and integrating responsive systems, next-generation materials adapt dynamically to the local microenvironment, promoting tissue integration rather than simple passive immune exclusion.

From inertia to interaction: a new paradigm

The major takeaway from this collection of work is the shift from a concept of "immune silence" to that of an active "immune dialogue." For the practitioner, this means that the success of a graft or an implant no longer depends solely on the direct stimulation of stem cells or osteoblasts, but on the biomaterial's ability to modulate the immune microenvironment. The study by Liu et al. illustrates this point through the use of polycaprolactone (PCL) scaffolds enriched with copper ions. This device achieves a critical balance: effective antibacterial action coupled with the promotion of osteogenesis, thanks to controlled ion release and recovery kinetics, thus avoiding the usual cytotoxicity of massive doses.

Periodontal complexity and systemic limitations

The analysis by Wang et al. on cementum regeneration highlights that the periodontal niche is a complex ecosystem where metabolism, epigenetic reprogramming, and microbial communities interact. This complexity explains the relative failures of conventional therapies that are "blind" to local immunity. However, the authors point out persistent limitations: the understanding of the spatio-temporal dynamics of immune cells remains incomplete. The transition to routine clinical application will require standardized validation models and better management of biological variability between patients. Furthermore, the integration of artificial intelligence is suggested to predict these complex immune responses in real time.

In concrete terms, for the practitioner:

• Rethinking the substitute: Do not see your biomaterials as passive structures anymore, but as vectors capable of actively directing macrophage polarization towards a pro-regenerative phenotype.
• Antibacterial synergy: The integration of ions (copper type) into guided bone regeneration (GBR) protocols now makes it possible to combine asepsis and osteogenic stimulation, limiting the risk of early infectious failure.
• Periodontal precision: Cementum regeneration requires a multifactorial approach targeting the metabolic and immune microenvironment rather than a simple volumetric filling approach.

Technical lexicon

Osteoimmunology: Disciplinary field exploring the bidirectional interactions between the immune system and bone tissue, essential for understanding how bone substitutes influence regeneration via the modulation of immune cells.

Macrophage polarization: A dynamic process by which macrophages modify their phenotype in response to microenvironmental stimuli, transitioning for example from a pro-inflammatory state to a pro-regenerative state, a key lever for biomaterial integration.

Guided Bone Regeneration (GBR): Surgical strategy using physical barriers (scaffolds) to promote bone growth; the study mentions the use of polycaprolactone (PCL) nanofibers to optimize this process.

Immune microenvironment: Dynamic complex of immune cells, chemical mediators, and signaling factors surrounding a tissue, acting as a conductor for inflammation, fibrosis, and tissue remodeling processes.

CIC (Cell-in-Cell) related genes: Genes regulating cell-in-cell phenomena (one living cell inside another), identified as regulators of immune heterogeneity and potential biomarkers for diagnosis and targeted therapies.

Immune dialogue: Paradigm shift in tissue engineering moving from the design of inert materials ("immune silence") to bioactive materials that actively interact with the host's immune system to guide repair.

Cementum regeneration: A complex process of reconstructing the mineralized tissue covering the tooth root, requiring precise modulation of the periodontal microenvironment (stem cell interactions, epigenetics, and metabolism).

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