Synthesis And Characterization Of Compound Photosensitizer Of Toluidine Blue And Single Wall Carbon Nanotubes

The surface area of carbon nanotubes(CNTs) is large, and most drug can be compounded to the carbon nanotube surface by the π-π bond. However, CNTs has limitations of poor aqueous solubility and biocompatibility, which significantly and negatively affect the application and development of carbon nanotube as a drug carrier. Photodynamic therapy with high safety and not leading drug resistance, has been used in clinical treatment in several countries. Toluidine blue(TB) is one of the main photosensitizers currently used for photodynamic therapy. However, it has limitations of poor water solubility and easy reunion, which significantly and negatively affect the efficiency of photodynamic therapy.Delivery of TB by using the large surface of carbon nanotubes is expected to inhibit the formation of multimers and improve its photodynamic effects. This paper firstly synthesized toluidine blue carbon nanotube compound photosensitizer by reflux method. CNTs were wrapped by chitosan(CS) or Carboxymethyl chitosan(cm Cs) to improve biocompatibility. The effects of temperature, time, carrier and p H on toluidine blue-carbon nanotube composite photosensitizer synthesis were respectively explored, which is expected to provide a theoretical basis for clinical application and development of TB. The main contents and results are as follows:(1) Tluidine blue-carbon nanotube composite photosensitizer were synthesized using reflow method at different reaction temperature and time. The analysis of their Raman spectra, transmission electron microscope images, fourier transform infrared spectra and visible spectroscopy, manifested: toluidine blue clad on CNTs; little effect of high temperature(90℃) and room temperature(60℃) on the synthesis of compound photosensitizer.TB coating on CNTs have the best effect when the reaction time is 24 h. The strongest absorption in the visible spectrum is located at 611 nm., which have a larger blue shift relatived to that of the TB monomer.(2) CNTs with different size and surface functional groups, which were modified with CS and cm CS, were repectively used to synthesize compound photosensitizer. The analysis of their transmission electron microscope images and visible spectroscopy, showed: little effect of CNTs with different size and surface functional groups on the synthesis of compound photosensitizer. CNTs modified with CS and cm CS is more conducive to the synthesis of complex photosensitizer, and compound photosensitizer of CNTs modified with cm CS has the strongest absorption in the visible spectrum and more.coating TB(3) Compound photosensitizer were respectively synthesized in an acidic(PH = 5) and alkaline(PH = 9) circumstance. The result showed that complex photosensitizer synthetized under basic conditions have stronger absorption of the visible light spectrum and more TB coat on CNTs compared to photosensitizer synthetized under the acidic conditions.