Researchers have made semiconducting cadmium sulphide nanoparticles1 using a fluorescent pigment isolated from a marine cyanobacterium. The pigment-labelled CdS NPs could be useful as a biolabel.
Semiconducting CdS NPs possess unique photochemical and photophysical properties. Synthesizing such NPs requires the use of hazardous chemicals. Microorganisms such as fungi, algae, yeast and bacteria are also capable of synthesizing CdS NPs. So far, however, there are few natural agents that can both synthesize and stabilize NPs.
To find such an agent, researchers isolated C-phycoerithrin (C-PE), a fluorescent pigment from the marine cyanobacterium Phormidium tenue . They allowed this pigment to react with a solution of cadmium chloride and sodium sulphide, yielding CdS NPs.
The CdS NPs measured approximately 5 nm in size, and remained so for well over eight months of storage. The researchers found that the fluorescent protein in the pigment contained amino acids such as tyrosine, phenylalanine and tryptophan. These amino acids stabilized the NPs and prevented agglomeration.
In studies with human cell lines, the researchers found C-PE to be non-toxic. Because the CdS NPs were synthesized in the aqueous phase using C-PE, they could be used to make novel fluorescence probes for the ultrasensitive detection of DNA.
The researchers say that the simplicity of their procedure will be useful for producing uniform-size, stable CdS NPs on a commercial scale.
The authors of this work are from: Department of Microbiology, School of Life Sciences, Bharathidasan University, and Department of Metallurgical and Materials Engineering, National Institute of Technology, Tiruchirappalli, and Department of Biotechnology, School of Bioengineering, SRM University, Chennai, Tamil Nadu, India.
