nanoreactors

Nanoreactors are nanoscale reaction environments in which chemical transformations occur within confined spaces, typically ranging from 1 to 1000 nanometers. They cover a variety of architectures, including encapsulated nanoparticles, polymeric capsules, liposomes, dendrimers, mesoporous silica particles, metal–organic frameworks, and surfaces functionalized to host reactive sites. In these systems, confinement and the local microenvironment influence reaction rates, selectivity, and pathways by modulating concentrations, diffusion, solvation, and heat transfer.

Designs of nanoreactors rely on self-assembly, templating, or selective functionalization of cores and shells. Common motifs include core–shell nanoparticles with active catalytic cores, porous shells that permit substrate access, and stimuli-responsive materials that activate or release reactive species under triggers such as pH, temperature, or light. Some nanoreactors integrate catalysts directly within the confined space, while others use protective compartments to stabilize sensitive active components.

Mechanistically, confinement can increase effective molarity, reduce side reactions, and enable tandem or cascade reactions within a single vessel. Immobilizing catalysts within nanoreactors aids separation and reuse, and protective shells are used to preserve enzyme activity in biocatalysis. In several cases, nanoreactors enable unique selectivity by creating distinct microenvironments that differ from bulk solution.

Applications span catalytic synthesis, fine- and pharmaceutical chemistry, polymerization, photocatalysis, and electrocatalysis. Nanoreactors also find use in biosensing and nanomedicine, where enzymes or catalysts are carried and shielded while performing reactions in targeted settings.

Key advantages include improved selectivity, milder conditions, enhanced safety, and easier product separation. Challenges involve reproducibility, scale-up, material stability, potential leakage, and detailed characterization of nanoscale processes. Ongoing research aims to integrate nanoreactors with flow systems and real-time monitoring for more efficient production.