Review
Nanoparticles and their biological and environmental applications

https://doi.org/10.1263/jbb.102.1Get rights and content

Nanoparticles exhibit unique physical properties (such as particle aggregation and photoemission, and electrical and heat conductivities) and chemical properties (such as catalytic activity), and hence have received much attention from scientists and researchers in different areas of biological sciences. In this review, we briefly summarize the major types of nanoparticle that have been used so far and discuss the possible applications of these nanoparticles in biological and environmental research, and the potential environmental and health impacts associated with the use of these nanoparticles.

Section snippets

Types of nanoparticles

Nanoparticles can be classified on the basis of the type of material into metallic, semiconductor and polymeric nanoparticles. Two metallic nanoparticles (that is gold and magnetic nanoparticles) and one semiconductor nanoparticle (that is quantum dots) are described here. Gold nanoparticles are associated colloids with dimensions ranging from 0.8–250 nm (3). They can be conjugated with different biomolecules simply through a biotin-(strept)avidin coupling reaction between biotinylated

Detection of biomolecules

Nanoparticles have been widely used as signal reporters to detect biomolecules in DNA assay, immunoassay and cell bioimaging. Usually, they are derivatized with different functional groups such as nucleic acid-targeted oligonucleotide probes, antibodies and protein to produce nanoprobes (Fig. 1A). Gold nanoparticle-based probes have been used in the identification of pathogenic bacteria in DNA-microarray technology (15). Results indicated that the melting profiles of target/probe hybrids can be

Microbial monitoring and detection

Although there are fewer applications of nanoparticles in environmental studies than in biomedical studies, the use of QDs as a fluorescence labeling system in microbial detection has been successfully demonstrated. Thiolated CdSe-core QDs could be conjugated with wheat germ agglutinin (WGA), a lectin that is commonly found in gram-positive bacteria (31). By reacting with bacterial cells, this QD-conjugated WGA can bind to sialic acid and N-acetylglucosaminyl residues on bacterial cell walls.

Environmental and health impacts

Although nanoparticles have received much attention for their applications in biological studies, various studies have shown the potential adverse effects of nanoparticles on human health and the environment (42). It is likely that waste generated during the production and use of these nanoparticles will appear eventually in various environments. There is a high possibility that human beings will be exposed to these nanoparticles through inhalation, dermal adsorption and digestion. The

Conclusions

Metallic and inorganic nanoparticles exhibit unique properties in terms of particle aggregation, photoemission, electrical and heat conductivity, and catalytic activity. These properties have recently been applied in different biological studies including bio-molecule detection, sample separation, purification and concentration, substrate coding, and signal transduction and amplification. In their application to environmental research, these nanoparticles further enhance the detection

Acknowledgments

This review article is contributed by WTL as the recipient of the Young Asian Biotechnologist Prize in 2005.

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