Determination of nucleic acid based on increased resonance light-scattering of fluorinated surfactants

The analytical application and spectral investigation of DNA-CPB-emodin and sensitive determination of DNA by resonance Rayleigh light scattering technique

A new sensitive DNA probe containing cetylpyridinium bromide (CPB) and emodin (an effective component of Chinese herbal medicine) was developed using the resonance Rayleigh light scattering (RLS) technique. A novel assay was first developed to detect DNA at nanogram level based on the ternary system of DNA-CPB-emodin. The RLS signal of DNA was enhanced remarkably in the presence of emodin-CPB, and the enhanced RLS intensity at 340.0 nm was in direct proportion to DNA concentration in the range of 0.01-2.72 μg mL(-1) with a good linear relationship. The detection limit was 1.5 ng mL(-1). Three synthetic DNA samples were measured obtaining satisfactory results, the recovery was 97.6-107.3%.

An investigation on the interaction of DNA with hesperetin/apigenin in the presence of CTAB by resonance Rayleigh light scattering technique and its analytical application

Two new systems for measuring DNA at nanogram levels by a resonance Rayleigh light scattering (RLS) technique with a common spectrofluorometer were proposed. In the presence of cetyltrimethylammonium bromide (CTAB), the interaction of DNA with hesperetin and apigenin (two effective components of Chinese herbal medicine) could enhance RLS signals with the maximum peak at 363 and 433 nm respectively. The enhanced intensity of RLS was directly proportional to the concentration of DNA in the range of 0.022-4.4 μg mL(-1) for DNA-CTAB-hesperetin system and 0.013-4.4 μg mL(-1) for DNA-CTAB-apigenin system. The detection limit was 2.34 ng mL(-1) and 2.97 ng mL(-1) respectively. Synthetic samples were measured satisfactorily. The recovery of DNA-CTAB-hesperetin system was 97.3-101.9% and that of DNA-CTAB-apigenin system was 101.2-109.5%.

Spectral study of interaction between poly(L-lysine)-poly(ethylene glycol)-poly(L-lysine) and nucleic acids

Polymer-DNA interactions have attracted considerable interests due to their important application in DNA transfection and cellular drug delivery technologies. In this work, a new detection assay for DNA is proposed with a tri-block copolymer poly(L-lysine)-poly(ethylene glycol)-poly(L-lysine) by resonance light scattering technique with the linear ranges from 0.0656 to 6.56 μg ml⁻¹. The detection limit for DNA is 0.42 ng ml⁻¹. Most coexisting substances do not interfere in the detection. UV-spectra and FTIR-spectra were employed to demonstrate the mechanisms of the interaction that the conformation of the DNA changes because the microenvironment of DNA changes.

Nucleic acids determination using the complex of eriochrome black T and silver nanoparticles in a resonance light scattering technique

A novel method for the determination of nucleic acids by using silver nanoparticle (AgNPs)-eriochrome black T (EBT) as a resonance light scattering (RLS) probe has been developed. Under optimum conditions, there are linear relationships between the quenching extent of RLS intensity and the concentration of nucleic acids in the range of 4.0×10(-9)-4.0×10(-7), 4.0×10(-7)-1.6×10(-6) g mL(-1) for fish sperm DNA (fsDNA) and 4.0×10(-8)-2.0×10(-6) g mL(-1) for yeast RNA (yRNA). Their detection limits (S/N=3) are 2.0 ng mL(-1) and 21 ng mL(-1), respectively. The results indicate that AgNPs can form wirelike aggregates and nanoslices in the presence of the EBT. Whereas, when nucleic acids are added into the AgNPs-EBT system, the dynamic balance of AgNPs-EBT system is destroyed and the nanoparticles undergo dispersion again, leading to the RLS intensity of AgNPs-EBT system quenching. Meanwhile, the conformation of fsDNA is changed by the synergistic effect of AgNPs and EBT.

Resonance scattering detection of trace melamine using aptamer-modified nanosilver probe as catalyst without separation of its aggregations

Nanosilver was modified by aptamer (ssDNA) to obtain a resonance scattering (RS) probe (AgssDNA) for melamine (MA). Based on the catalytic effect of the probe on the Fehling particle reaction, a nanocatalytic RS assay is proposed for the determination of 0.02-1.06 μg L(-1) MA.