Modality switching between therapy and imaging based on the excitation wavelength dependence of dual-function agents in folic acid-conjugated graphene oxides.

Owing to its near infrared (NIR) absorption, graphene oxide (GO) is promising for both photothermal (PT) therapy and multiphoton (MP) imaging. Novel therapy/imaging modality switching is proposed here based on the selected excitation wavelength of femtosecond (FS) laser. GO-based destruction of cancer cells is demonstrated when the laser power of 800-nm-wavelength FS laser is increased above 7 mW. However, GO-based imaging is mainly monitored without damaging the sample when using 1200-nm wavelength FS laser in the same laser power range. Folic acid (FA) conjugated graphene oxide (FA-GO) was synthesized for selective cancer cell targeting. Dual-function FA-GO-based cancer cell targeting agents were experimentally optimized to enable therapy/imaging modality switching.

Unfolding displacement measurement method for the aliasing interferometer signal of a wavelength-comb-swept laser.

We demonstrate an unfolding displacement measurement method to overcome the aliasing problem of wavelength-comb-swept laser (WCSL). Compared to the conventional wavelength-swept laser (WSL), the WCSL exhibits an extended coherence length, owing to the narrowing spectral linewidth of the etalon filter. However, the aliasing interference signal induces an unexpected back-bounced phenomenon during displacement measurement because of the discretely distributed comb-like periodic spectra of the etalon filter. By using the dual-reference interferometry method, the back-bounced displacement measurement can be successfully unfolded to extend the measurement range by two times. In addition, we demonstrate a longer-range surface profiling image over 18 mm within the 200 mm of measurement range using a line-field beam of a parallel-swept source-optical coherence tomography system.

Acousto-Optic-Based Wavelength-Comb-Swept Laser for Extended Displacement Measurements.

We demonstrate a novel wavelength-comb-swept laser based on two intra-cavity filters: an acousto-optic tunable filter (AOTF) and a Fabry-Pérot etalon filter. The AOTF is used for the tunable selection of the output wavelength with time and the etalon filter for the narrowing of the spectral linewidth to extend the coherence length. Compared to the conventional wavelength-swept laser, the acousto-optic-based wavelength-comb-swept laser (WCSL) can extend the measureable range of displacement measurements by decreasing the sensitivity roll-off of the point spread function. Because the AOTF contains no mechanical moving parts to select the output wavelength acousto-optically, the WCSL source has a high wavenumber (k) linearity of R² = 0.9999 to ensure equally spaced wavelength combs in the wavenumber domain.

Effects of maternal genetic polymorphisms in vitamin D-binding protein and serum 25-hydroxyvitamin D concentration on infant birth weight.

OBJECTIVE: Vitamin D deficiency is a common problem during pregnancy and might contribute to adverse birth outcomes. Vitamin D-binding protein plays a key role in regulating vitamin D metabolism. We investigated whether maternal genetic variation in GC, the gene encoding vitamin-D binding protein, modulates the relationship between 25-hydroxyvitamin D [25(OH)D] levels and infant birth weight. METHODS: We measured 25(OH)D concentrations in maternal and umbilical cord blood from 356 pregnant women and their infants by liquid chromatography tandem mass spectrometry. We extracted DNA from the maternal blood for genotyping GC single-nucleotide polymorphisms (SNPs). RESULTS: The 25(OH)D concentrations were significantly higher in the maternal blood than in the cord blood, although the concentrations from each source were positively correlated with one another among individuals. Maternal GC SNPs rs12512631 and rs7041 were not significantly associated with infant birth weight. On the other hand, the GC SNPs rs12512631 and rs7041 significantly modified the relationships between the maternal and cord-blood concentrations of 25(OH)D and birth weight. Low 25(OH)D levels in the maternal and cord blood were significantly associated with decreased birth weight among infants born to mothers carrying the rs12512631 'C' allele but not in those born to mothers homozygous for the 'T' allele (P-interaction = 0.043 and 0.0008 for the maternal and cord blood, respectively). Low 25(OH)D levels in the cord blood were significantly associated with decreased birth weight only among infants born to mothers carrying the rs7041 'G' allele (P-interaction = 0.009). CONCLUSIONS: Our findings suggest that the interaction between 25(OH)D status and some maternal GC variants influence the birth weight of infants.

The use of chitosan as a condensing agent to enhance emulsion-mediated gene transfer.

Previously we have formulated a new cationic emulsion, composed of 3beta [N-(N',N'-dimethylaminoethane) carbamoyl] cholesterol and dioleoylphosphatidyl ethanolamine, castor oil and Tween 80, and it efficiently delivered plasmid DNA into various cancer cells with low toxicity. Chitosan is a natural cationic polysaccharide and is able to form polyelectrolyte complexes with DNA, in which the DNA is condensed and protected against nuclease degradation. Based on these facts, chitosan was used as a condensing agent to enhance the transfection efficiency of cationic emulsion-mediated gene delivery vehicle. The particle size, zeta potential and transmission electron micrographs of DNA/emulsion complexes were observed before and after condensation by chitosan. In vitro transfection efficiency of naked or precondensed DNA/emulsion (pcDNA/E) complexes was investigated in human hepatoma cells (HepG2) using flow cytometer, confocal microscope and western blot. In addition, in vivo gene transfer was also evaluated as GFP mRNA expression by reverse transcriptase-polymerase chain reaction. The size of transfection complexes was reduced after the condensation of DNA by chitosan. Moreover, when the pcDNA/E complexes were administered into the mice, the GFP mRNA expression was prolonged in liver and lung until day 6. These results suggest that the use of chitosan enhance the in vitro transfection efficiency and extend in vivo gene transfer.