Virus-like particles as catalytic nanoreactors: Confinement effects, characterization strategies, and future opportunities

Virus-like particles (VLPs) are increasingly recognized as programmable, bioinspired nanoscale scaffolds capable of operating as confined catalytic nanoreactors with precise control over molecular transport and reactivity. Their defined capsid architectures create uniform internal reaction volumes and engineered pore systems that regulate substrate diffusion, stabilize encapsulated catalysts, and reshape reaction kinetics and selectivity beyond what is achievable in bulk solution. This review critically examines VLPs as particulate nanoreactors, emphasizing how advances in capsid design, encapsulation strategies, and surface functionalization govern catalytic behavior. We highlight mechanistic insights into how nanoscale confinement influences turnover stability, substrate discrimination, and thermodynamic profiles, including cases where confinement redirects reaction pathways rather than simply enhancing rates. Recent progress in high-resolution and in situ characterization techniques is discussed, demonstrating how real-time monitoring of catalytic events within VLP lumens has strengthened structure–function correlations. Emerging applications in biosensing, sustainable biocatalysis, environmental remediation, and synthetic biology are evaluated with attention to performance metrics and scalability. Finally, key challenges related to structural robustness, manufacturability, and predictive engineering are outlined as critical considerations for industrial translation. VLP-based nanoreactors thus represent a versatile platform bridging biological self-assembly with materials engineering for controlled and environmentally compatible catalytic transformations.