Size-Dependent Biological Activities of Fluorescent Organosilane-Modified Zinc Oxide Nanoparticles

Mariana Buşilă, Aurel Tăbăcaru, Viorica Muşsat, Bogdan Ştefan Vasile, Ionela Andreea Neaşu, Teresa Pinheiro, Catarina Roma-Rodrigues, Pedro V. Baptista, Alexandra R. Fernandes, António Pedro Matos, Fernanda Marujo Marques

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Surface modification of zinc oxide nanoparticles (ZnO NPs) is a strategy to tune their biocompatibility. Herein we report on the synthesis of a series of fluorescent ZnO NPs modified with 2-10% (3-glycidyloxypropyl)trimethoxysilane (GPTMS) to investigate the fluorescence properties and to explore their applications in microbiology and biomedicine. The obtained ZnO NPs were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). Size reduction occurred from ca. 13 nm in unmodified ZnO to 3-4 nm in silane-modified samples and fluorescence spectra showed size-dependent variation of the photoemission bands' intensity. The antibacterial and cytotoxic activities were investigated on Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, and in ovarian (A2780) and prostate (PC3) cancer cells by tetrazolium/formazan-based methods. The antibacterial effect was higher for E. coli than S. aureus, while the cytotoxic activity was similar for both cancer cells and varied with the particle size. Cell death by apoptosis, and/or necrosis versus autophagy, were explored by flow cytometry using an Annexin V based-method and transmission electron microscopy (TEM). The main mechanism of ZnO NPs toxicity may involve the generation of reactive oxygen species (ROS) and the induction of apoptosis or autophagy. This work revealed the potential utility of GPTMS-modified ZnO NPs in the treatment of bacterial infection and cancer.

Original languageEnglish
Pages (from-to)137-152
Number of pages16
JournalJournal of biomedical nanotechnology
Issue number2
Publication statusPublished - 1 Feb 2020


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