Details

Autor(en) / Beteiligte

• Qian, Hai Sheng
• Guo, Hui Chen
• Ho, Paul Chi-Lui
• Mahendran, Ratha
• Zhang, Yong

Titel

Mesoporous-Silica-Coated Up-Conversion Fluorescent Nanoparticles for Photodynamic Therapy

Ist Teil von

• Small (Weinheim an der Bergstrasse, Germany), 2009-10, Vol.5 (20), p.2285-2290

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2009

Quelle

Access via Wiley Online Library

Beschreibungen/Notizen

• Near‐infrared (NIR)‐to‐visible up‐conversion fluorescent nanoparticles have potential to be used for photodynamic therapy (PDT) in deep tissue because NIR light can penetrate thick tissue due to weak absorption in the optical window. Here a uniform layer of mesoporous silica is coated onto NaYF4 up‐converting nanocrystals, with a large surface area of ≈770 m2 g−1 and an average pore size of 2 nm. A photosensitizer, zinc phthalocyanine, is incorporated into the mesoporous silica. Upon excitation by a NIR laser, the nanocrystals convert NIR light to visible light, which further activates the photosensitizer to release reactive singlet oxygen to kill cancer cells. The photosensitizer encapsulated in mesoporous silica is protected from degradation in the harsh biological environment. It is demonstrated that the photosensitizers loaded into the porous silica shell of the nanoparticles are not released out of the silica while they continuously produce singlet oxygen upon excitation by a NIR laser. The nanoparticles are reusable as the photosensitizers encapsulated in the silica are removed by soaking in ethanol. A uniform layer of mesoporous silica is coated onto NaYF4 up‐converting nanocrystals and a photosensitizer, zinc phthalocyanine (ZnPc), is incorporated into the mesoporous silica (see image). Upon excitation by a near‐infrared (NIR) laser, the nanocrystals convert NIR light to visible light, which further activates the photosensitizer to release reactive singlet oxygen.