Biomedical Engineering Reference
In-Depth Information
TABLE 3.4
Types of Nanosystems with Their Sizes, Characteristics, and Application
Type of Nanosystem
Characteristics
Applications
Carbon nanotubes
Size: 0.5-3 nm and
20-1000 nm length
• Third allotropic crystalline form of carbon
sheets either single layer (single-walled
nanotube, SWNT) or multiple layer
(multi-walled nanotube, MWNT)
• These crystals have remarkable strength
and unique electrical properties
(conducting, semiconducting, or insulating)
• Functionalization enhanced solubility,
penetration to cell cytoplasm and to nucleus,
as carrier for gene delivery, peptide delivery
Nanocrystals
Quantum dots
Size: 2-9.5 nm
• Broad UV excitation and high
photostability
• Bright fluorescence
• Semiconducting properties
• Narrow emission
• Long-term multiple color imaging of liver
cell
• DNA hybridization
• Immunoassay
• Receptor-mediated endocytosis
• Labeling of breast cancer marker HeR
2
surface of cancer cells
Iron oxide nanocrystal
Size: 4-5 nm;
Hydrodynamic radius:
15-25 nm
• Superparamagnetism
• Magnetic resonance imaging (disease
detection such as cancer, arthritis, and
atherosclerosis)
• Intracellular monitoring
Dendrimer
Size: <10 nm
• Highly branched, nearly monodisperse
polymer system produced by controlled
polymerization
• Three main parts—core, branch, and
surface
• Long circulatory, controlled delivery of
bioactives
• Targeted delivery of bioactives to
macrophages
• Liver targeting
Silica nanoparticles
Size: 10 nm-50 μm
• Silanized and coated with oligonucleotide.
Observable by fluorescence method
• Efficient nucleic acid hybridization
• Detection of DNA
• Nanobiosensor for trace analysis
Polymeric micelles
Size: 10-100 nm
• Amphiphilic block copolymer micelles
• High drug entrapment, payload, and
biostability
• Long circulatory, target specific active and
passive drug delivery
• Diagnostic value
Liposomes
Size: 50-100 nm
• Phospholipid vesicles
• Biocompatible
• Good entrapment efficiency
• Offer easy surface functionalization
• Long circulatory time
• Offer passive and active delivery of gene,
protein, peptide, and various other bioactives
Metallic nanoparticles
Size: <100 nm
• Gold and silver colloids
• Very small size resulting in high surface
area available for functionalization
• Better stability
• Drug and gene delivery
• Highly sensitive diagnostic assays
• Thermal ablation and radiotherapy
enhancement
Polymeric nanoparticles
Size: 10-1000 nm
• Biocompatible and biodegradable
• Offer complete drug protection
• Excellent carrier for controlled and sustained
delivery of drugs
• Stealth and surface-modified nanoparticles
can be used for active and passive delivery of
bioactives
Nanoshells
• Nanoshells typically have a silicon core
that is sealed in an outer metallic core
• By manipulating the ratio of wall to core,
the shells can be precisely tuned to scatter
or absorb very specific wavelengths of light
• Gold-encased nanoshells have been used to
convert light into heat, enabling the
destruction of tumors by selective binding to
malignant cells
Source:
Data adapted from Nahar, M. et al. 2006.
Crit Rev Ther Drug Carrier Syst
23(4): 259-318.
