Study on the resonance light-scattering spectrum of lysozyme-DNA/CdTe nanoparticles system

The interactions of lysozyme and calf thymus DNA (ctDNA) or thioglycolic acid (TGA) modified CdTe nanoparticles in aqueous solution have been studied by resonance light-scattering (RLS) spectroscopy. At pH 7.2 Britton-Robinson (BR) buffer solution and pH 7.4 phosphate buffered saline (PBS), the RLS signals of ctDNA and TGA modified CdTe nanoparticles were greatly enhanced by lysozyme in the region of 220-750 nm characterized by the peak around 306 and 353 nm, respectively. Under optimal conditions, the increase of RLS intensity of the two systems is proportional to the concentration of lysozyme. The linear range is 0.1-25 microg/ml for the lysozyme-ctDNA system, and 0.2-10.7 microg/ml for the lysozyme-TGA modified CdTe nanoparticles system. The detection limit is 0.041 microg/ml for the lysozyme-ctDNA system, and 0.083 microg/ml for the lysozyme-TGA modified CdTe nanoparticles system, respectively. Meanwhile lysozyme can also be used as a probe to determine the ctDNA. The increase of RLS intensity of the system is also proportional to the concentration of ctDNA. The linear range is 0.078-13 microg/ml. The detection limit is 0.024 microg/ml. Three kinds of samples were analyzed with satisfactory results.