ABSTRACT
Current treatments for cancer and the central nervous system diseases are limited,partly due to the difficulties posed by the insolubility,poor distribution of drugs among cells and lack of selectivity of drugs,the inability of drugs to cross cellular barriers and blood brain barrier (BBB).Carbon nanotubes (CNTs) possess many distinct properties including good electronic properiies,remarkably penetrating capability on the cell membrane,high drug-loading and pH-dependent therapeutic unloading capacities,thermal properties,large surface area and easy modification with molecules,which render them as a suitable candidate to deliver drugs to cancer and brain.CNTs as a drug delivery could achieve a high efficacy,enhance specificity and diminish side effects.Whereas CNTs have been primarily employed in cancer treatment,a few studies have focused on the treatment and diagnosis of the central nervous system diseases using CNTs.Here,we review the current progress of in vitro and in vivo researches of CNTs-based drug delivery to cancer involving CNTs-based tumor-targeted drug delivery systems (DDS),photodynamic therapy (PDT) and photothermal therapy (PTT).Meanwhile,we also review the current progress of in vitro and in vivo researches of CNTs-based drug delivery to brain.
ABSTRACT
OBJECTIVE Hypericin, a powerful naturally photosensitizer in photodynamic therapy (PDT), is suitable for treating skin diseases involving excess capillary proliferation. In the present study, we aimed to evaluate the skin penetrability of a topically applied hypericin, expecting reducing the risk of prolonged skin photosensitivity, which often occurs after systemic administration. METHODS The Franz diffusion cell assay was performed to evaluate different penetration enhancers. In vivo studies, fluorescence microscopy was performed to examine the distribution of hypericin in the skin, macroscopic and microscopic analyses were also carried out to detect pathological changes in the skin after topical hypericin-PDT treatment. Immunohistochemistry was used to determine the expression of PECAM-1 in the treated skin. RESULTS 5% menthol facilitated hypericin penetrate the skin of nude mice most. The results of in vivo assays revealed that hypericin penetrated nude mice skin, spread to the dermis, and resulted in obvious photosensitivity reaction on the dermal capillaries. Moreover, skin injured by the photosensitive reaction induced by hypericin was replaced by normal skin 7 d after hypericin-PDT treat?ment. CONCLUSION Topical hypericin could penetrate nude mouse skin well and be great potential in PDT treatment of skin diseases.