RESEARCH PAPER In vitro cytotoxic effects of modified zinc oxide quantum dots on breast cancer cell lines (MCF7), colon cancer cell lines (HT29) and various fungi Zahra Fakhroueian • Alireza Mozafari Dehshiri • Fatemeh Katouzian • Pegah Esmaeilzadeh Received: 29 December 2013 / Accepted: 28 April 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract An important ideal objective of this study was to perform surface functionalization of fine (1–3 nm) ZnO quantum dot nanoparticles (QD NPs) in order to inhibit decomposition and agglomeration of nanoparticles in aqueous media. Polymers, oily herbal fatty acids, PEG (polyethylene glycol), and organosi- lanes are the main reagents used in these reactions, because they are completely soluble in water, and can be used as biological probes in nanomedicine. Veg- etable fatty acid-capped ZnO (QD NPs) was fabricated by dissolving at a suitable pH after sol–gel method in the presence of nonionic surfactants as efficient templates with a particular HLB (hydrophilic-lipo- philic balance) value (9.7 and 8.2). In the present research, we focused on the cellular toxicity of fine zinc oxide QD NPs containing particular blue fluorescence for targeted delivery of MCF7 and HT29 cancer cell lines. The IC50 values were determined as 10.66 and 5.75 lg/ml for MCF7 and HT29, respectively. These findings showed that ZnO QDs have low toxicity in normal cells (MDBK) and can display potential application in cancer chemother- apy in the near future. These properties could result in the generation of a promising candidate in the field of nanobiomedicine. The robust-engineered ZnO QD NPs showed their antibacterial and antifungal activ- ities against Bacillus anthracis, Staphylococcus aur- eus, Klebsiella pneumonia, and Staphylococcus epidermidis bacteria and also different fungi such as Microsporum gypseum, Microsporum canis, Tricho- phyton mentagrophytes, Candida albicans, and Can- dida tropicalis, compared with the standard antibiotic agents like Gentamicin and Clotrimazol. Keywords ZnO quantum dots  Surface modification  Breast cancer lines MCF7  Colon cancer cell lines HT29  Cytotoxic MDBK test  Selective toxicity  Antifungal drug  Anticancer Introduction Nanoparticles are nowadays making important con- tributions to the development of novel aims of drug delivery in cancer, and can provide a platform due to their solubility in water, surface modifications, Z. Fakhroueian (&) School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran e-mail: fakhroueian@ut.ac.ir A. M. Dehshiri Department of Traditional Pharmacy, Faculty of Traditional Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran F. Katouzian Microbiology Department, Azad University of Pharmaceutical Science, Tehran, Iran P. Esmaeilzadeh Biomedical Materials Group, Institute of Pharmacy, Martin Luther University, Halle-Wittenberg, Germany 123 J Nanopart Res (2014) 16:2483 DOI 10.1007/s11051-014-2483-2