Nanoparticles are classified based on their composition, structure, and origin into several major categories:
By Composition:
- Metal nanoparticles: Gold, silver, copper, platinum, aluminum – known for electrical conductivity and catalytic properties
- Metal oxide nanoparticles: Zinc oxide, titanium dioxide, iron oxide – valued for antimicrobial, UV-blocking, and magnetic properties
- Ceramic nanoparticles: Silica, alumina – used for mechanical strength and thermal stability
- Polymeric nanoparticles: Biodegradable polymers like PLGA, chitosan – ideal for drug delivery
- Lipid-based nanoparticles: Liposomes, solid lipid nanoparticles – pharmaceutical carriers
- Carbon-based nanoparticles: Carbon nanotubes, graphene, fullerenes – exceptional mechanical and electrical properties
- Semiconductor nanoparticles: Quantum dots (CdSe, ZnS) – unique optical properties for imaging and displays
By Dimensionality:
- Zero-dimensional (0D): Quantum dots, spherical nanoparticles – all dimensions at nanoscale
- One-dimensional (1D): Nanowires, nanotubes, nanorods – one dimension extends beyond nanoscale
- Two-dimensional (2D): Nanosheets, graphene, thin films – two dimensions extend beyond nanoscale
By Origin:
- Engineered nanoparticles: Intentionally synthesized for specific applications
- Incidental nanoparticles: Byproducts of industrial processes or combustion
- Natural nanoparticles: Found in volcanic ash, ocean spray, biological systems
Each type offers unique properties suited to specific applications, from electronics and catalysis to medicine and environmental remediation.