Influence of apple phytochemicals in ZnO nanoparticles formation, photoluminescence and biocompatibility for biomedical applications

• Published in: Materials Science & Engineering C Vol. 101; pp. 76 - 87
• Main Authors: Alves, Marta M., Andrade, Suzana M., Grenho, Liliana, Fernandes, Maria H., Santos, Catarina, Montemor, Maria F.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2019; Elsevier BV
• Subjects: Actin; Adequacy; Apple; Apples; Biocompatibility; Biocompatible Materials - pharmacology; Bioimaging; Biomedical materials; Biomedical Technology - methods; Cell Death - drug effects; Cell viability; Crystal defects; Cytoskeleton; Cytotoxicity; Decay; Dermis - cytology; Emission; Fibroblasts; Fibroblasts - cytology; Fibroblasts - drug effects; Fluorescence; Food industry; Food processing industry; Humans; Luminescence; Malus - chemistry; Materials science; Medical imaging; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Microparticles; Microscopy; Mitochondria; Nanoparticles; Near ultraviolet radiation; Photoluminescence; Photons; Phytochemicals; Phytochemicals - chemistry; Phytochemicals - pharmacology; Properties (attributes); Quercetin; Skin; Solutions; Spectrophotometry, Ultraviolet; Sucrose; Sugar; Toxicity; Zinc oxide; Zinc Oxide - chemistry; Bioimaging; Cytotoxicity; Zinc oxide; Apple; Phytochemicals; Photoluminescence
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2019.03.084

The new green-synthesised ZnO nanoparticles (NPs) using apple (var. Starking) phytochemicals present a great potential for bioimaging applications. These NPs, when compared with ZnO microparticles synthesised with pure phytochemicals (quercetin or sucrose), and water, revealed that sizes and shapes were widely dependent on the organic precursors used. Based on these findings, new insights into the synthesis of ZnO NPs using apple phytochemicals were presented. The photoluminescent properties, characterized by steady-state and time resolve photoluminescence measurements, revealed that besides the intense sharp near-UV band edge emission observed for all particles, with sub-nanosecond lifetime, a strong broad emission band peak at 2.20 eV was detected for microparticles, with longer decay times being associate to crystal defects. Additionally, the photoluminescent properties of ZnO particles, further explored by fluorescence lifetime imaging microscopy (FLIM), suggested adequacy for imaging applications. The cytotoxicity, evaluated in human dermal fibroblasts, proving the biosafety of ZnO NPs by an unaffected cellular viability, total mitochondrial activity and F-actin cytoskeleton organization, contrasted with some degree of cytotoxicity depicted for microparticles. The influence of the phytochemicals in ZnO cytotoxicity was discussed. To the authors' best knowledge this is the first report of ZnO NPs synthesised with apple extracts. The novelty of choosing a fruit widely used in the food industry will render affordable NPs through the concept of circular economy. The proved biosafety of these ZnO NPs together with their intrinsic photoluminescent properties, open perspectives for the development of cost-effective bioimaging materials with potential to be further directed into biomedical applications. [Display omitted] •Apple phytochemical pools rendered functionalized ZnO NPs•Pure water and pure phytochemicals (quercetin or sucrose) yielded ZnO microparticles•Both NPs and microparticles have an intense near-UV band edge emission•When apple extracts are used, a great diminishing in visible emissions contributions of NPs is attained•While NPs showed a good biocompatibility on fibroblasts, microparticles evidenced some cytotoxicity