10 research outputs found
Nanostructured Oxygen Sensor - Using Micelles to Incorporate a Hydrophobic Platinum Porphyrin
Hydrophobic platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP) was physically incorporated into micelles formed from poly(ε-caprolactone)-block-poly(ethylene glycol) to enable the application of PtTFPP in aqueous solution. Micelles were characterized using dynamic light scattering (DLS) and atomic force microscopy (AFM) to show an average diameter of about 140 nm. PtTFPP showed higher quantum efficiency in micellar solution than in tetrahydrofuran (THF) and dichloromethane (CH2Cl2). PtTFPP in micelles also exhibited higher photostability than that of PtTFPP suspended in water. PtTFPP in micelles exhibited good oxygen sensitivity and response time. This study provided an efficient approach to enable the application of hydrophobic oxygen sensors in a biological environment
Micelles as Delivery Vehicles for Oligofluorene for Bioimaging
With the successful development of organic/polymeric light emitting diodes, many organic and polymeric fluorophores with high quantum efficiencies and optical stability were synthesized. However, most of these materials which have excellent optical properties are insoluble in water, limiting their applications in biological fields. Herein, we used micelles formed from an amino-group-containing poly(ε-caprolactone)-block-poly(ethylene glycol) (PCL-b-PEG-NH2) to incorporate a hydrophobic blue emitter oligofluorene (OF) to enable its application in biological conditions. Although OF is completely insoluble in water, it was successfully transferred into aqueous solutions with a good retention of its photophysical properties. OF exhibited a high quantum efficiency of 0.84 in a typical organic solvent of tetrahydrofuran (THF). In addition, OF also showed a good quantum efficiency of 0.46 after being encapsulated into micelles. Two cells lines, human glioblastoma (U87MG) and esophagus premalignant (CP-A), were used to study the cellular internalization of the OF incorporated micelles. Results showed that the hydrophobic OF was located in the cytoplasm, which was confirmed by co-staining the cells with nucleic acid specific SYTO 9, lysosome specific LysoTracker Red®, and mitochondria specific MitoTracker Red. MTT assay indicated non-toxicity of the OF-incorporated micelles. This study will broaden the application of hydrophobic functional organic compounds, oligomers, and polymers with good optical properties to enable their applications in biological research fields
Retention percentage of PtTFPP from PCL-<i>b</i>-PEG micelles.
<p>Retention percentage of PtTFPP from PCL-<i>b</i>-PEG micelles.</p
Photophysical properties of PtTFPP in micelles, THF and CH<sub>2</sub>Cl<sub>2</sub> solutions.
<p>Photophysical properties of PtTFPP in micelles, THF and CH<sub>2</sub>Cl<sub>2</sub> solutions.</p
Response time studied through a saturation of air and nitrogen saturation to the micellar solutions (A) and through the consumption of the oxygen by the oxidation of glucose by glucose oxidase (B).
<p>Concentration of glucose was 0.25 M and the concentration of the glucose oxidase was 10 mg/mL.</p
DLS of the micelles (A) and AFM image of the dried micelles (B).
<p>DLS of the micelles (A) and AFM image of the dried micelles (B).</p
Typical oxygen sensing of the PtTFPP/PCL-<i>b</i>-PEG micelles excited at 390 nm (A).
<p>Stern-Volmer responses of the micelles excited at 390, 405, and 514 nm (B).</p
Chemical structures of PtTFPP and PCL-<i>b</i>-PEG and the schematic drawing of the micelle formation.
<p>Chemical structures of PtTFPP and PCL-<i>b</i>-PEG and the schematic drawing of the micelle formation.</p
Photostability of PtTFPP in PCL-<i>b</i>-PEG micelles (A) and PtTFPP suspended in 5% THF-containing HEPES buffer (B).
<p>Photostability of PtTFPP in PCL-<i>b</i>-PEG micelles (A) and PtTFPP suspended in 5% THF-containing HEPES buffer (B).</p