d-(+)-Galactose-conjugated single-walled carbon nanotubes (SWCNTs) were synthesized for use as biosensors to detect the cancer marker galectin-3. To investigate the binding of galectin-3 to the d-(+)-galactose-conjugated SWCNTs, an electrochemical biosensor was fabricated by using molybdenum electrodes. The binding affinities of the conjugated SWCNTs to galectin-3 were quantified using electrochemical sensitivity measurements based on the differences in resistance together with typical I-V characterization. The electrochemical sensitivity measurements of the d-(+)-galactose-conjugated SWCNTs differed significantly between the samples with and without galectin-3. This indicates that d-(+)-galactose-conjugated SWCNTs are potentially useful electrochemical biosensors for the detection of cancer marker galectin-3.

In this study, the effect of light activated agent, methyl (pyro)pheophorbide-a, which bears non-aromatic cyclic compound, excited with red light from a LED on the viability of S. aureus, S. epidermidis, and E. coli was investigated. All species were susceptible to killing by photosensitization and photodynamic effect was dependent on both the chemical structure and concentration. However, E. coli was not susceptible to concentrations used to obtain a significant kill with the Gram-positive bacteria upon irradiation. To more closely mimic the conditions of wounds, photodynamic therapy was carried out on S. aureus, which is the most important organism that can cause a range of mild to severe infections in skin and burn wounds, in the presence of human blood plasma and human serum albumin, representing a wound fluid model. Results indicate that microorganisms could be successfully photoinactivated by tropolone methyl (pyro)pheophorbide-a derivatives when suspended in phosphate buffered saline. However, changing the medium into 4.5% and 7% HSA/PBS solutions reduced the effectiveness of lethal photosensitization of bacteria. The same results were obtained with human blood plasma. Also, the mechanism of bacterial cell inactivation by a sensitizer and light was studied with reactive oxygen species scavengers. Further evidence of the involvement of singlet oxygen is provided by the protective effect of the singlet oxygen scavenger, sodium azide.

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Carbohydrate-conjugated chlorins were synthesized for use as biosensors for the detection of the galectin-3 cancer marker. We used ELISA, SDS-gel electrophoresis, and Bradford assays to examine the binding of galectins to D-(+)-galactose-and β-lactose-conjugated chlorins. The binding affinities of these conjugated chlorins for galectin-3 were quantified using fluorescence spectroscopy. The fluorescence emission of the carbohydrate-conjugated chlorins decreased as the amount of galectin-3 in the binding reaction increased over a limited concentration range, indicating that carbohydrate-conjugated chlorins are potentially useful fluorescence biosensors for the galectin-3 cancer marker.