(236f) Carboxy SNARF-1 Nanoreactors Protected From Dye-Protein Interactions, with Fast pH Response and Reduced Photobleaching

A nanoreactor with dual-wavelength fluorescence function for pH detection is developed in this project. The pH nano-sensor is made with calcium phosphate coated phosphatidylcholine liposomes with encapsulation of carboxy-SNARF-1 (cSNARF-1) dye. Particle mean size was analyzed to be 150 nm in diameter by using transmission electron microscopy and dynamic light scattering. Comparative analyses of fluorescence pH titration were performed with pH nano-sensor and pure dye carried out in water, and in the presence of the plasma, albumin and IgG The results show that the dye encapsulated nanoreactor minimized the serious distortions of the pH titration plots in the presence of albumin and plasma. The modified Henderson-Hasselbach equation was used to estimate the pKa values of the pure dye and dye encapsulated nanoreactor in different solution. The results indicate that when the dye encapsulated in nanoreactor, pH values were stable over time, photobleaching resistant, and reproducible under cyclic pH changes. The stopped flow fluorometric device was used to measure pH response time of dye encapsulated nanoreactor and revealed less than 200 msec. The fluorescence microscope was used to observe the particles and detect their colorimetric response in reference to the pH change. The observation also shows pH nano-sensor particles can maintain it integrity under continuous illumination up to 80 min. The dual-wavelength fluorescence dye encapsulated in nanoreactor shows a quick pH measurement, the shell coating provided the protection and extended pH range sensor ideal for use in biological system, microfluidics device and other complicate micro/nano environments.