How are nanoparticles made?

How are nanoparticles made?

Nanoparticles are synthesized through two fundamental approaches: 

Top-Down Methods: Breaking down bulk materials into nanoscale particles through mechanical milling, lithography, etching, or laser ablation. While straightforward, these methods often produce irregular particle sizes, introduce contaminants, and struggle to achieve uniform properties at scale. 

Bottom-Up Methods: Building nanoparticles atom-by-atom or molecule-by-molecule through chemical reactions. This approach includes: 

• Chemical synthesis: Precipitation, sol-gel, hydrothermal, and solvothermal methods where chemical reactions in solution produce nanoparticles with controlled properties 

• Gas-phase synthesis: Flame spray pyrolysis, chemical vapor deposition, and inert gas condensation 

• Biological synthesis: Using microorganisms, plants, or enzymes to produce nanoparticles (green synthesis) 

Key Synthesis Parameters: Regardless of method, controlling nanoparticle properties requires precise management of: 

• Reagent concentrations and purity 

• Reaction temperature and time 

• pH and ionic strength 

• Mixing and flow dynamics 

• Surface stabilizers and capping agents 

Modern continuous flow reactor systems enable precise control over these parameters, producing nanoparticles with consistent size, morphology, and performance characteristics that batch methods cannot reliably achieve.