¹台北市立聯合醫院忠孝院區外科部泌尿科；²國立成功大學光電科學與工程學系；³國立屏東大學應用化學系；⁴國立陽明大學醫學院泌尿學科

Che-Wei Hsu¹, Nei-Chi Cheng², Mei-Yi Liao³, Chih-Chia Huang², Yi-Chun Chiu^{1, 4}

¹Division of Urology, Dept. of Surgery, Taipei City Hospital Zhongxiao Branch, Taipei, Taiwan

²Dept. of Photonics, National Cheng Kung University, Tainan, Taiwan

³Dept. of Applied Chemistry, National Pingtung University, Pingtung, Taiwan

⁴ Dept. of Urology, School of Medicine, National Yang-Ming University, Taipei, Taiwan

 

Bladder cancer is one of the most common cancer of the genitourinary tract. There are limited treatment options for patients with recurrent non-muscle-invasive bladder cancer.
Photodynamic therapy (PDT), which uses an interaction between absorbed light and a retained photosensitizing agent to destroy tissue, has been used to treat bladder cancer.
Toxic effect of nanoparticles on nonmalignant cells is the primary concern of their medical applications. T24 and SV-HUC-1 cell line were established from human urinary bladder cancer cells and human normal urothelial cells respectively.
Herein, we use gold nanoparticles (NPs) combined with methylene blue (MB), called Au@MB NPs, as a photosensitizer under exposure of laser illumination and measure the cell toxicity in different cell line.

For Au@MB NPs, 1 mL 5 mM HAuCl4 solution were mixed with fresh 2.5 mM tannic acid at room temperature, evolving for 30 min before addition of MB was performed. We started fractional adding 5 mM 25 μL MB per 5 minutes a time. In the end, the solution were purified by centrifugation at 10000 rpm for ten minutes with de-ionized water for 2 times.
T24 cells were incubated with Au@MB NPs (0-10 ppm [Au]) for 45 mins, 2 hours and 4 hours followed by illumination with 660 nm laser light (125 mW/cm2) for 8mins. Afterwards, the illuminated cells were incubated for 24 hours and the cell viability were measured by Thiazolyl Blue Tetrazolium Bromide (MTT) assay.
Normal human urothelial cells (SV-HUC-1) were used to evaluate the toxic effect of Au@MB NPs on normal tissues. SV-HUC-1 cells were incubated with Au@MB NPs for 4 hours, followed by illumination with 660 nm laser light (125 mW/cm2) for 8mins. Cell viability was assessed by MTT assay.

T24 cells treated various concentrations of Au@MB NPs were all alive after short incubation time (45 mins). When increasing incubation time to 2 hours, 10 ppm [Au] Au@MB NPs could reduce the cell viability to 57.2 %. For longer incubation time (4 hours), the cell viability was decreased to 26.6 % (Fig. 1). The cell viability of SV-HUC-1 cells treated with Au@MB NPs followed by laser illumination was nearly no decreased (96.01± 11.68 %) (Fig. 2).

 

Au@MB NPs successfully performed efficiency for bladder cancer cells in PDT. This in vitro result demonstrated that Au@MB NPs were targeting toward cancer cells rather than normal urothelial cells, which showed the promising application of Au@MB NPs in PDT for bladder cancer treatment.

Figure 1. Cytotoxicity of Au@MB NPs in T24 cell line with different concentration and various incubation time.

Figure 2. Cytotoxicity of Au@MB NPs in SV-HUC-1 cell line with different concentration and various incubation time.