ZnO Nanostructures for Tissue Engineering Applications

This review focuses on the most recent applications of zinc oxide (ZnO) nanostructures for tissue engineering. ZnO is one of the most investigated metal oxides, thanks to its multifunctional properties coupled with the ease of preparing various morphologies, such as nanowires, nanorods, and nanoparticles. Most ZnO applications are based on its semiconducting, catalytic and piezoelectric properties. However, several works have highlighted that ZnO nanostructures may successfully promote the growth, proliferation and differentiation of several cell lines, in combination with the rise of promising antibacterial activities. In particular, osteogenesis and angiogenesis have been effectively demonstrated in numerous cases. Such peculiarities have been observed both for pure nanostructured ZnO scaffolds as well as for three-dimensional ZnO-based hybrid composite scaffolds, fabricated by additive manufacturing technologies. Therefore, all these findings suggest that ZnO nanostructures represent a powerful tool in promoting the acceleration of diverse biological processes, finally leading to the formation of new living tissue useful for organ repair

Porous Zinc Oxide Thin Films: Synthesis Approaches and Applications

Zinc oxide (ZnO) thin films have been widely investigated due to their multifunctional properties, i.e., catalytic, semiconducting and optical. They have found practical use in a wide number of application fields. However, the presence of a compact micro/nanostructure has often limited the resulting material properties. Moreover, with the advent of low-dimensional ZnO nanostructures featuring unique physical and chemical properties, the interest in studying ZnO thin films diminished more and more. Therefore, the possibility to combine at the same time the advantages of thin-film based synthesis technologies togetherwith a high surface area and a porous structuremight represent a powerful solution to prepare ZnO thin films with unprecedented physical and chemical characteristics that may find use in novel application fields. Within this scope, this review offers an overview on the most successful synthesis methods that are able to produce ZnO thin films with both framework and textural porosities. Moreover, we discuss the related applications, mainly focused on photocatalytic degradation of dyes, gas sensor fabrication and photoanodes for dye-sensitized solar cells

BIOMIMETIC NON - IMMUNOGENIC NANOASSEMBLY FOR THE ANTITUMOR THERAPY

Nanoassembly ( 1 ) for inducing apoptosis in cancer cells comprising : a core ( 2 ) comprising at least a nanoparticle of a nano structured and semiconductor metal oxide , said nanoparticle being monocrystalline or polycrystalline ; a shell ( 3 ) formed by a double phospholipid layer and proteins derived from an extracellular biovesicole chosen between an exosome , an ectosome , a connectosome , an oncosome and an apoptotic body , and an oncosome , said core ( 2 ) being enclosed inside said shell ( 3 ) ; and a plurality of targeting molecules ( 4 , 4 ' , 4 " ) of said cancer cells , preferably mono clonal antibodies ( 4 , 4 ' , 4 " ) , said molecules ( 4 , 4 , 4 " ) being anchored to the external surface of said biovesicole

Nanoparticle-assisted ultrasound: a special focus on sonodynamic therapy against cancer

At present, ultrasound radiation is broadly employed in medicine for both diagnostic and therapeutic purposes at various frequencies and intensities. In this review article, we focus on therapeutically-active nanoparticles (NPs) when stimulated by ultrasound. We first introduce the different ultrasound-based therapies with special attention to the techniques involved in oncological field, then we summarize the different NPs used, ranging from soft materials, like liposomes or micro/nano-bubbles, to metal and metal oxide NPs. We therefore focus on the sonodynamic therapy and on the possible working mechanisms under debate of NPs-assisted sonodynamic treatments. We support the idea that various, complex and synergistics physical-chemical processes take place during acoustic cavitation and NP activation. Different mechanisms are therefore responsible for the final cancer cell death and strongly depends on not only the type and structure of NPs or nanocarriers, but also on the way they interact with the ultrasonic pressure waves. We conclude with a brief overview of the clinical applications of the various ultrasound therapies and the related use of NPs-assisted ultrasound in clinics, showing that this very innovative and promising approach is however still at its infancy in the clinical cancer treatment

Assessment of antioxidant and drug releasing properties of cellulose fabrics functionalized with polymeric nanoparticles as potential biofunctional garments

Drug administration through skin raised a great interest as a not invasive and sustained method to deliver active substances both at topical and systemic levels. Biofunctional textiles are a new class of materials that combine conventional fabrics with advanced drug delivery systems in order to develop a wearable functional biomaterial [1]. The present research aims to functionalize cellulosic fabrics (e.g. cotton and viscose) with curcumin (CUR)-loaded polycaprolactone (PCL) nanoparticles (NPs) in order to assess their potential as biofunctional garments. The NPs were produced by the flash nanoprecipitation technique in a confined impinging jet mixer. Such technology was proven to be a simple and scalable approach to produce polymeric nanoparticles; moreover it was successfully applied to curcumin encapsulation [2]. Nanoparticles were then characterized in terms of size and zeta potential by dynamic light scattering (DLS), while the loading capacity (LC%) and encapsulation efficiency (EE%) were measured by exploiting fluorescence spectroscopy. Cotton and viscose fabrics were functionalized by imbibition with the NPs suspensions and the effectiveness of the treatment was observed under wide-field fluorescence microscopy. The release properties of the nanoparticles suspensions were studied in vitro in a multicompartment rotating cell, while the curcumin release from textile support was tested ex vivo in a Franz diffusion cell using porcine skin as membrane. Furthermore, the antioxidant activity of the NPs and of the functionalized fabrics was measured by electron paramagnetic resonance spectroscopy. Curcumin loaded NPs were successfully prepared with good control of particle size and loading capacity, high stability over several days and encapsulation efficiency higher than 99%. Nanoparticles were successfully attached to the textiles material as evidenced by fluorescent imaging. The prepared materials showed an improved antioxidant activity and the capability of controlling curcumin release both in vivo and ex vivo. The present research shows the possibility of producing biofunctional materials by simple and scalable process and opens a route for a new generation of garments that can benefit people health

In-vitro evaluation of bioactive and biodegradation properties of mesoporous ZnO architectures

Currently there is strong interest in the development of smart piezoelectric biomaterials for tissue engineering, where piezoelectricity may actively promote the growth, proliferation and differentiation of cells. [1] Piezoelectric Zinc Oxide (ZnO) materials may be easily prepared in high-surface area structures by several techniques, and captured considerable attention due to their biocompatibility and antibacterial properties. [2] Despite being widely investigated for sensors and energy harvesting applications, [3] the study of ZnO-based materials for tissue engineering is still in its infancy. Herein, we propose a preliminary investigation on the in-vitro bioactive and biodegradation behavior of high-surface area mesoporous ZnO layers, after soaking in Simulated Body Fluid (SBF) solution for different times. The ZnO samples were obtained by thermal oxidation of Zn layers sputtered on silicon substrates. The morphology, crystal structure, and chemical composition of the ZnO samples were studied before and after in-vitro tests. Our results show the rapid formation of CaP structures after soaking in SBF for few hours, then resulting into the formation of a CaP-rich layer onto the whole ZnO surface for prolonged soaking times. The mesoporous ZnO architecture was preserved during the overall in-vitro experimental analyses, with negligible release of biodegradation products from the ZnO structure. [1] C. Ribeiro, V. Sencadas, D.M. Correia, and S. Lanceros-Méndez, Colloids. Surf. B, 136 (2015) 46-55. [2] Y. Zhang, T. R. Nayak, H. Hong, and W. Cai, Curr. Mol. Med. 13 (2013) 1633-1645. [3] M. Laurenti, G. Canavese, A. Sacco, M. Fontana, K. Bejtka, M. Castellino, C.F. Pirri, and V. Cauda, Adv. Mater. 27 (2015) 4218-4223