Ni0.5Zn0.5Fe2O4 nanoparticles-decorated poly (vinyl alcohol) nanofiber as resonance light scattering probe for determination of sunitinib in serum samples

Nickel zinc ferrite (Ni_0.5Zn_0.5Fe₂O₄) nanoparticles decorated poly (vinyl alcohol) was constructed by the electrospinning method and used for determining the sunitinib amount in real sample. In this study, resonance light scattering (RLS) technique was used for studying the interaction of nanofibers with sunitinib. Similar Ni_0.5Zn_0.5Fe₂O₄ nanoparticles-decorated nanofibers with average diameter of 200 nm and length up to several millimeters were prepared. The morphology and microstructure of the as prepared Ni _0.5Zn _0.5Fe₂O₄ nanoparticles-decorated nanofibers were studied in details. The nanofibers were characterized by energy dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. The nanofibers are formed through assembling magnetic nanoparticles with poly (vinyl alcohol) as the structure-directing template. Under the optimal conditions, the linear dynamic range and RSD were 5.0 × 10^-3-10.0 mg L^-1 and 1.62% (n = 3), respectively. A limit of detection of 1.0 × 10^-3 mg L^-1 sunitinib was obtained from this method. The obtained results showed successful application of the method for the analysis of sunitinib in real samples.

Assay of miRNA in cell samples using enhanced resonance light scattering technique based on self aggregation of magnetic nanoparticles

AIMS

miRNAs are regarded as potential biomarkers correlated with the development and progression of many diseases. However, it is a challenge to construct a sensitive method to detect them without using time-consuming radioactive labeling or complex amplification strategies.

METHODS

A facile resonance light scattering (RLS) system was developed for the detection of miRNA employing magnetic nanoparticles (MNPs) as RLS probes. MNPs were coated with streptavidin. DNA probes were modified on the surface of MNPs based on the specific interaction of streptavidin and biotin forming MNPs@DNA probes. MNPs@DNA probes dispersed in homogeneous media causing low RLS signal.

RESULTS & CONCLUSION

miRNA hybridized with DNA probes resulting in the aggregation of MNPs and inducing the enhancement of RLS intensity. miRNAs were determined successfully with limit of detection at 0.9 picomole per liter (pM). The potential clinical application of the present biosensor was also demonstrated by measuring miRNAs in human normal and cancer cells, and human serum samples.

A simple cyanide sensing probe based on Ag/Fe3O4nanoparticles

The first direct approach in ultra-trace cyanide determination through a simple, selective and rapid reaction by simply-synthesized recyclable Ag/Fe₃O₄nanostructures.

Combining a loop-stem aptamer sequence with methylene blue: a simple assay for thrombin detection by resonance light scattering technique

Schematic illustration of the RLS aptasensor for selective detection of human thrombin.

Nanoscopic poly-DNA-cleaver for breast cancer regression with induced oxidative damage

A novel strategy for efficient "nanodelivery" of DNA-cleaving molecules for breast cancer regression is presented here. The synthetic methodology can be tweaked for controlled delivery and better bioavailability of effective doses of these DNA-cleaving agents through a defined self-assembled polymeric nanoarchitecture. In vitro studies in ER+ and ER- breast cancer human cell lines confirmed an efficient "nano"-delivery of DNA-cleaving molecules and indicated their capability to mediate oxidative damage to nucleobases and/or to the 2-deoxyribose moiety. Prepared E-poly-DNA-cleaver and C-poly-DNA-cleaver were found to be interacting with plasmid DNA pBR322 (pDNA) and active to cause oxidative cleavage of pDNA in the presence of ascorbic acid and H2O2. They were found to be significantly active as DNA cleaving agents in vitro and showed highly improved cancer regression in MCF-7 and MD-MB231 cancer cells compared to small molecule DNA cleaver. Surface conjugated nanoparticles were found to be more effective than noncovalent encapsulation and the small molecule agent, whereas in all the cases RCM was significantly inactive toward DNA cleavage. Blood contact complement activation properties were evaluated to gauge their likelihood to promote acute toxicity following systemic administration. The complement activation analyses together with the blood smear study confirm the feasibility of using these poly-DNA-cleavers without risk of induced immune response.

Chitosan-capped gold nanoparticles for selective and colorimetric sensing of heparin

In this contribution, novel chitosan-stabilized gold nanoparticles (AuNPs) were prepared by mixing chitosan with citrate-reductive AuNPs under appropriate conditions. The as-prepared chitosan-stabilized AuNPs were positively charged and highly stably dispersed in aqueous solution. They exhibited weak resonance light scattering (RLS) intensity and a wine red color. In addition, the chitosan-stabilized AuNPs were successfully utilized as novel sensitive probes for the detection of heparin for the first time. It was found that the addition of heparin induced a strong increase of RLS intensity for AuNPs and the color change from red to blue. The increase in RLS intensity and the color change of chitosan-stabilized AuNPs caused by heparin allowed the sensitive detection of heparin in the range of 0.2-60 μM (~6.7 U/mL). The detection limit for heparin is 0.8 μM at a signal-to-noise ratio of 3. The present sensor for heparin detection possessed a low detection limit and wide linear range. Additionally, the proposed method was also applied to the detection of heparin in biological media with satisfactory results.

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%.