菁染料的研究及应用已有100多年的历史，近年来，它们在生物方面的应用研究已取得一定的成果。本文就近几年菁染料及其衍生物在生物医疗方面的研究及进展情况加以综述，特别阐述了这类染料用作荧光探针在生物大分子标识以及作为光敏剂在光动力疗(PDT)中用于恶性肿瘤的诊断与治疗这两方面的研究进展。

Novel smart materials can be synthesized and designed at the molecular level by attaching well characterized and tailored functionalities to be used in in vitro and in vivo oximetry. A series of porphyrins and metalloporphyrins were synthesized and their EPR and UV-vis spectra studied. The steric hindrance and electronic effects of the substituted groups and the characteristics of different metal ions were the major contributors in influencing the properties of the compounds. As a result, their EPR and UV-vis spectra changed. Through studying the EPR spectroscopic properties of these compounds, we hope that novel EPR oximetry materials can be found and this will help to extend the applications of EPR oximetry in vivo.

New electron paramagnetic resonance (EPR) oximetry probes were identified in the class of carbon black materials. These compounds exhibit very high oxygen sensitivity and favorable EPR characteristics for biological applications. At low pO2, the linewidth is particularly sensitive to changes in oxygen tension (sensitivity of 750 mG/mmHg). The application of the probes for oximetry was demonstrated in vivo: the pO2 was measured in muscle in which the blood flow was temporarily restricted as well as in tumor-bearing mice during a carbogen breathing challenge. The responsiveness to pO2 was stable in muscle for at least 3 months. No toxicity was observed using these materials in cellular experiments and in histological studies performed 2, 7, and 28 days after implantation. In view of their EPR characteristics (high sensitivity) as well as the well-characterized production procedure that make them available on a large scale, these probes can be considered as very promising tools for future developments in EPR oximetry. Magn Reson Med 51:1272-1278, 2004.

Langmuir-Blodgett films of mixtures of fatty acids (FA) and a merocyanine dye (DS), bearing one long alkyl chain and one carboxylic group, were prepared at a nitrogen-pure water interface. The films exhibit a distinct and highly anisotropic J-band near 605 nm, even though they do not contain any metallic or ammonium cations. Although an isotropic band was seen in the region of 500-550 nm, the contribution of the J-aggregates was extracted from the observed visible and IR absorption spectra by using the difference in the polarization of the bands. This analysis indicates a change in the electronic structure of DS in the J-aggregates, probably corresponding to intramolecular charge transfer. Furthermore, this analysis also suggests that in this metalfree case, the formation of the J-aggregates is strongly affected by the hydrogen bonding between the carboxylic groups in two DS and that between the carboxylic groups in DS and FA.

Head-to-tail molecular arrangements of J-aggregates modify not only the excited state, but also the ground state of the dye chromophore therein. To clarify such modification of the ground state, which is related with the aggregation mechanism, infrared absorption spectroscopy has been applied to J-aggregates of two alkylated merocyanine dyes, 6MeDS and DO, formed in their pure or mutually mixed Langmuir-Blodgett films. Some vibrational modes have been found to be softened upon the J-aggregation. The nature of these vibrational modes has been determined by density functional calculations. Then, it has been concluded that the J-aggregation induces an enhancement of intramolecular charge transfer both in the 6MeDS and DO cases, although these two dyes are largely different in their tendency to form J-aggregates.