RESUMO
Surface-enhanced Raman scattering (SERS)-based aptasensor platform, using double strand DNA-embedded Au/Ag core-shell nanoparticles, has been developed for the ultrasensitive detection of bisphenol A (BPA) in water. By combining optimally controlled Au/Ag core-shell nanoparticles with the selective BPA binding characteristics of DNA aptamers, a highly sensitive limit of detection (LOD) of 10 fM could be achieved for BPA-spiked tap water over a wide concentration range from 100 nM to 10 fM. This LOD is two or three orders of magnitude lower than that reported for other BPA sensing techniques, and also yields a detection limit that is 100-1000 times lower than the US EPA-defined Predicted No Effect Concentration (PNEC) values in potable water. Total detection time is estimated to be about 40 min including the reaction between aptamer and BPA (30 min) and detection (10 min). This sensing platform is also suitable for field applications since measurement can be performed under aqueous colloidal conditions.
Assuntos
Aptâmeros de Nucleotídeos/química , Compostos Benzidrílicos/análise , Água Potável/química , Nanopartículas Metálicas/química , Fenóis/análise , Análise Espectral Raman/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Poluentes Químicos da Água/análise , Aptâmeros de Nucleotídeos/genética , Monitoramento Ambiental/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Microquímica/instrumentaçãoRESUMO
Epidermal growth factor receptor (EGFR) has been recognized as an important prognostic marker expressed in cancer cells because its activation is associated with key features of cancer including tumor growth, survival, angiogenesis, and metastasis. Cetuximab is the first monoclonal antibody drug that targets EGFR overexpressed in cancer cells. It easily binds to EGFR, thereby down-regulating the receptor, blocking EGFR-mediated tyrosine kinase activity, and inhibiting cellular proliferation. Thus, EGFR-cetuximab binding can be quantified to monitor receptor status and the prognosis of cancer therapy. In this work, we report using SERS imaging to assess the inhibitory effect of cetuximab on EGFR expressed on cancer cells. From SERS mapping images using silica-encapsulated gold nanotags, the localized spatial distribution of EGFR that was not inhibited by cetuximab could be determined. Furthermore, EGFR expression could be accurately quantified through the statistical analysis of surface-enhanced Raman scattering (SERS) spectral data. Our experimental data demonstrate the feasibility of SERS imaging to improve the prognostic efficacy of cetuximab treatment.
Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Biomarcadores Tumorais/imunologia , Neoplasias da Mama/imunologia , Receptores ErbB/imunologia , Imunoensaio/métodos , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos , Linhagem Celular Tumoral , Cetuximab , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Luz , Refratometria/métodos , Reprodutibilidade dos Testes , Espalhamento de Radiação , Sensibilidade e EspecificidadeRESUMO
We report the rapid and highly sensitive trace analysis of mercury(ii) ions in water using a surface-enhanced Raman scattering (SERS)-based microdroplet sensor. Aptamer-modified Au/Ag core-shell nanoparticles have been fabricated and utilized as highly functional sensing probes. All detection processes for the reaction between mercury(II) ions and aptamer-modified nanoparticles were performed in a specially designed microdroplet channel. Small water droplets that included sample reagents were separated from each other by an oil phase that continuously flowed along the channel. This two-phase liquid-liquid segmented flow system prevented the adsorption of aggregated colloids to the channel walls due to localized reagents within encapsulated droplets. The result was reduced residence time distributions. The limit of detection (LOD) of mercury(II) ions in water was determined by the SERS-based microdroplet sensor to be below 10 pM, which is three orders below the EPA-defined maximum contaminant level. This combination of a SERS-based microfluidic sensor with aptamer-based functional nanoprobes can be used for in-the-field sensing platforms, due to its size and simplicity.
Assuntos
Aptâmeros de Nucleotídeos/química , Ouro/química , Mercúrio/análise , Nanopartículas Metálicas/química , Prata/química , Análise Espectral Raman , Carbocianinas/química , Íons/química , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Óleos/química , Água/químicaRESUMO
A micro-battery powered by tritium is being developed to utilize tritium produced from the Wolsong Tritium Removal Facility. The 3D p-n junction device has been designed and fabricated for energy conversion. Titanium tritide is adopted to increase tritium density and safety. Sub micron films or nano-powders of titanium tritide is applied on silicon semiconductor device to reduce the self absorption of beta rays. Until now protium has been used instead of tritium for safety. Hydrogen was absorbed up to atomic ratio of approximately 1.3 and approximately 1.7 in titanium powders and films, respectively.
