Table 3.

Comparative analysis of ApoEVs vs. canonical osteogenic proteins/growth factors in bone healing

Comparison dimension	Apoptotic extracellular vesicles (ApoEVs)	Canonical osteogenic proteins/growth factors	Ref.
Signal structure & cargo	Membrane-encapsulated, multimodal carriers that act as integrated “information packages,” capable of co-delivering proteins, lipids, and nucleic acids simultaneously	Primarily soluble proteins (e.g., BMPs, TGF-β, IGFs, FGFs, PDGFs, VEGF) or pathway ligands (e.g., Wnts) that signal through their cognate cell-surface receptors	[86, 110, 115]
Multiplexing & pathway coverage	High intrinsic multiplexing potential: a single vesicle can carry multiple bioactive cues to coordinate diverse cellular programs, including immune modulation, matrix remodeling, osteogenesis, and angiogenesis-osteogenesis coupling	Typically act in a module- or pathway-specific manner. Broader niche coordination requires the sequential action of multiple factors within a network
Spatiotemporal availability	Injury-coupled production: generated locally in damaged tissues during repair/remodeling, as part of apoptosis and subsequent cellular clearance processes	Availability is governed by endogenous expression, release, diffusion, and degradation kinetics. Exogenous supplementation requires controlled delivery to achieve therapeutic timing and localization
Delivery & engineering	The bilayer membrane structure protects cargo and supports direct intercellular transfer. Conceptually well-suited for engineering strategies to enable targeted delivery or depot-based release	Soluble proteins often require additional carriers or depot systems to enhance local retention and dose control. Diffusion and rapid clearance can limit effective therapeutic exposure
Standardization & quality control	Demands rigorous standardization across the entire workflow: from defining the source material, inducing apoptosis, isolating vesicles, and characterizing them (including distinguishing them from EVs released by viable cells)	Molecular identity is well-defined and easily quantifiable. However, biological outcomes are highly dependent on dose, timing, and local presentation, often requiring specialized delivery systems for spatiotemporal control in repair settings