ORIGINAL ARTICLE Sensitivity of A-549 human lung cancer cells to nanoporous zinc oxide conjugated with Photofrin Muhammad Fakhar-e-Alam & Syed Muhammad Usman Ali & Zafar Hussain Ibupoto & Khun Kimleang & M. Atif & Muhammad Kashif & Foo Kai Loong & Uda Hashim & Magnus Willander Received: 8 April 2011 /Accepted: 1 September 2011 /Published online: 1 October 2011 # Springer-Verlag London Ltd 2011 Abstract In the present study, we demonstrated the use of nanoporous zinc oxide (ZnO NPs) in photodynamic therapy. The ZnO NPs structure possesses a high surface to volume ratio due to its porosity and ZnO NPs can be used as an efficient photosensitizer carrier system. We were able to grow ZnO NPs on the tip of borosilicate glass capillaries (0.5 μm diameter) and conjugated this with Photofrin for efficient intracellular drug delivery. The ZnO NPs on the capillary tip could be excited intracellularly with 240 nm UV light, and the resultant 625 nm red light emitted in the presence of Photofrin activated a chemical reaction that produced reactive oxygen species (ROS). The procedure was tested in A-549 cells and led to cell death within a few minutes. The morphological changes in necrosed cells were examined by microscopy. The viability of control and treated A-549 cells with the optimum dose of UV/visible light was assessed using the MTT assay, and ROS were detected using a fluorescence microscopy procedure. Keywords Lung cancer (A-549) cells . MTT assay Photofrin . Cell viability . Nanoporous zinc oxide (ZnO NPs) . Reactive oxygen species (ROS) . Photodynamic therapy (PDT) Introduction Activation of a photosensitizer/nanomaterial system by UV light (240 nm) results in tissue necrosis by direct killing or vascular blockade due to singlet oxygen release from the mitochondria [1–3]. In the field of nanomedicine and nanotechnology numerous nanomaterial metal oxides of variable chemistry and architecture have been introduced for cancer diagnosis and treatment, and involve the use of multifunctional engineering devices [4–6]. There are many emerging applications involving the use of nanomaterials that make use of the physical, chemical and biological behavior of materials at the nanoscale size [7, 8]. It is considered that nanotechnology will have a positive impact on basic sciences and in particular on clinical applications such as photodynamic therapy (PDT) [9]. M. Fakhar-e-Alam : S. M. U. Ali (*) : Z. H. Ibupoto : K. Kimleang : M. Willander Department of Science and Technology, Campus Norrköping, Linköping University, SE-60174 Norrköping, Sweden e-mail: syeal@itn.liu.se M. Fakhar-e-Alam e-mail: fakharphy@gmail.com M. Fakhar-e-Alam Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650, Pakistan S. M. U. Ali Department of Electronic Engineering, NED University of Engineering and Technology, Karachi 75270, Pakistan M. Atif Laser Diagnosis of Cancer, Physics and Astronomy Department, College of Science, King Saud University, Riyadh, Saudi Arabia M. Kashif : F. K. Loong : U. Hashim Nano Biochip Research Group, Institute of Nano Electronic Engineering (INEE), University Malaysia Perlis (UniMAP), 01000 Kangar, Perlis, Malaysia M. Atif National Institute of Laser and Optronics, Nilore, Islamabad 45650, Pakistan Lasers Med Sci (2012) 27:607–614 DOI 10.1007/s10103-011-0989-8