Smart and Safe packaging

In line with the latest innovations in the packaging field, this joint project aims at implementing new and innovative micro- and nanoparticles for the development of active and intelligent packaging solutions dedicated to food and medical packaging applications. More specifically, the project combines two major developments which both falls within the scope of active and intelligent packaging. In this work, a specific focus was given to the development of an antibacterial packaging solution and to the development of smart gas sensors. The antibacterial strategy developed was based on the combination of two active materials - silver nanowires and cellulose nanofibrils - to prepare antibacterial surfaces. The formulation as an ink and the deposition processing has been deeply studied for different surface deposition processes that include coatings or screen-printing. Results showed surfaces that display strong antibacterial activity both against Gram-positive and Gram-negative bacteria, but also interesting properties for active packaging applications such as a highly retained transparency or enhanced barrier properties. Regarding the second strategy, gas sensors have been prepared using a combination of Copper benzene-1,3,5-tricarboxylate Metal Organic Framework and carbon-graphene materials, deposited on flexible screen-printed electrodes. The easy-to-produce and optimized sensors exhibit good performances toward ammonia and toward humidity sensing, proving the versatility and the great potential of such solution to be adapted for different target applications. The results of this project lead to innovative solutions that can meet the challenges raised by the packaging industry

Electrospinning of composite biomaterials: incorporation of bioactive agents and formation of hierarchical nanostructures

This PhD focused on promotion of bioactivity of electrospun fibres. Two methods were used to achieve this objective: using antimicrobial agents and, creating hierar-chical structures.Antimicrobial agents, essential oils and zinc oxide nanoparticles, were encapsulat-ed in polymer nanofibres to promote antimicrobial properties. Tea tree and Manuka essential oils were encapsulated in poly (lactic acid) (PLA) by dissolving in their common solvent acetone and then electrospin. Plasticising effect of essential oils was observed in differential scanning calorimetry (DSC)test. Glass transition temperature of PLA fibres decreased with increasing essential oil concen-tration. This corresponded with mechanical results. Manuka/PLA fibres showed successful result in inhibition of E. coli in antimicrobial test.Zinc oxide nanoparticles have previously been used in electrospun fibres for anti-microbial purpose. To my knowledge, previous studies have only achieved to en-capsulate zinc oxide nanoparticles directly in electrospun fibres. In this thesis, for the first time, zinc oxide nanoparticles were first in-situ synthesised in polyethylene-imine (PEI) and then combined with zein to electrospin fibres. Resulting fibres showed better mechanical properties when compared to pure electrospun zein fi-bres.The second method, creating hierarchical structure, was achieved by phase separa-tion. An unique dual-porosity structure of electrospun poly(ethyl cyanoacry-late)/polycaprolactone (PECA/PCL) was demonstrated. Composition of fibres was confirmed by Fourier-transform infrared spectroscopy (FTIR). Hierarchical structures are believed to favour cell attachment and proliferation by increasing fibre surface roughness and surface-to-volume ratio.</div

Прва међународна конференција о електронској микроскопији наноструктура ELMINA 2018, 27-29 август 2018. Београд, Србија

ELMINA2018 International Conference organized by the Serbian Academy of Sciences and Arts and the Faculty of Technology and Metallurgy, University of Belgrade, as the first in a series of electron microscopy conferences: Electron Microscopy of Nanostructures. The scope of ELMINA2018 will be focused on electron microscopy, which provides structural, chemical and electronic information at atomic scale, applied to nanoscience and nanotechnology (physics, chemistry, materials science, earth and life sciences), as well as advances in experimental and theoretical approaches, essential for interpretation of experimental data and research guidance. It will highlight recent progress in instrumentation, imaging and data analysis, large data set handling, as well as time and environment dependent processes

Templated synthesis of polymer nanocapsules: the role of template characteristics in dictating the efficiency of drug delivery systems

The fabrication and employment of nano-size vehicles for the effective delivery of drugs for therapeutic applications is an emerging and promising field in nanotechnology. Although a diverse range of drug delivery vehicles exist today, most lack the finer control over their size and monodispersity which is essential if they are to be introduced into the body. This thesis exploits template particles for the fabrication of polymeric nanocapsules with structurally unique characteristics. To achieve this, silica nanoparticles acting as templates were first investigated, where the effects of the experimental parameters on the size and monodispersity of the templates was explored and optimised using both single and multivariable experiments, so that the particles could be tailored to their required application. Following template fabrication, a comparison study of two template-facilitated approaches to nanocapsules synthesis were investigate and the combination of the solid core/mesoporous shell (SC/MS) approach along with the polymer material chitosan was found to be the most effective drug delivery system (DDS). Through modification of the same SC/MS approach, seven structurally unique chitosan nanocapsules were fabricated and the size of the vehicle was identified to be the most influential characteristic when comparing the cytotoxic efficiency. The body of this work identifies a promising nanocapsular drug delivery system for the future, which was demonstrated good control over the size and monodispersity of the nanocapsules, a high loading capacity for the water-liable drug curcumin, biocompatibility and high cytotoxic efficiency when the drug is incorporated

I The synthesis and coordination chemistry of novel 1,1,1-tris(aminomethyl)ethane (TAME) derived ligands and their use as size selective fluorescent zinc(II) sensors II The synthesis of strongly and weakly binding ligands with nitrogen, oxygen, and sulfur-donor groups to be used as receptors in fluorescent ratiometric indicators for transition metal ions

The Ni(II)-mediated template synthesis of the novel chelator TAMEpyr, where TAMEpyr =N,N\u27,N -tris(2-pyridylmethyl)-1,1,1-tris(aminomethyl)ethane, and its coordination chemistry with a host of metal ions is presented. Structural data for [Zn(TAMEpyr)]2+ show the propensity of the ligand for an octahedral coordination geometry. Solution studies of TAMEpyr further illustrate the chelator\u27s flexibility. Lastly, the pyridyl groups of the parent ligand TAMEpyr were exchanged with a host of azaheterocycles affording a collection of novel TAME derived chelators. The Ni(II)-template chemistry developed to prepare the novel chelator TAMEpyr was exploited in the preparation of novel Zn(II)-selective fluorescent sensors. The molecules TAMEisoquin and 6,7-DMTI possess the fluorophore-spacer-receptor design motif that is evident in many photoinduced electron transfer (PET) based metal-ion sensors. These molecules display exquisite spectroscopic selectivity for Zn(II) with target-induced fluorescence enhancements of ca. 14 and 17 respectively. The measured quantum yield for [Zn(TAMEisoquin)]2+ was a dismal 1.2%. This was improved, however, to 20% for [Zn(6,7-DMTI)] 2+. The thermodynamic stability imparted to the target analyte from the polydentate N6-donor set was evidenced in the measured K d\u27 of 1.4 fM for [Zn(TAMEisoquin)]2+. Unlike many reported sensors, the TAME-based chelators display excellent selectivity for Zn(II) over Cd(II). Moreover, the synthetic flexibility of the TAME podand for additional functionalization may facilitate the development of novel bifunctional luminescent sensors. Work on TAME derived azacoumarins is presented. Lastly, swelling polymeric networks built from N-isopropylacrylamide (NIPA) have been prepared toward the sensing of Cu(II). The candidate\u27s role in this collaborative project was to synthesize strongly and weakly binding metal ion receptors to be copolymerized into the polyNIPA network. Fluorescent groups were also copolymerized into this network which acted as luminescent reporters upon analyte recognition. Depending on the charge of the bound metal-receptor complex the polymer either became swollen or shrank. Polymer shrinking brought the donor-acceptor pair closer together such that fluorescence resonance energy transfer (FRET) increased. Conversely, reduction of like charges within the polymeric network caused the polymer to swell thus attenuating the measured FRET. This section describes the ligating systems chosen to be incorporated into the polyNIPA systems and the results obtained for the sensing of Cu(II) is presented

Recent Developments of Electrodeposition Coating

This e-book presents a selection of papers focused on some novel aspects of electrodeposited coatings, in particular for medical applications. The biocoatings applied for surface modification of load-bearing implants are still being developed, especially for titanium implants, for which hundreds and thousands of possible technical solutions have been proposed using different techniques and materials. This book is a collection of papers that demonstrate appropriate attempts using various electrodeposition methods. The specific objectives are different, with several looking for improved bioactivity, another for antibacterial properties, and another for increased adhesion on the helix lines on dental implants. The e-book starts with a paper on the methodic development of electrodes for electrowinning. This is followed by paper on the real performance of the surface of dental implants, a subject not often addressed. The next paper focuses on electro-oxidation: a novel two-stage oxidation method, characteristic of the oxide layer on helix line of a model dental implant, and micro-arc oxidation of 3D printed titanium. The last paper focuses on coatings, describing the carbon nanotubes- (hydroxyapatite, chitosan), Eudragit-, and Fe-containing coatings. The e-book concludes with a review of all electrodeposition methods. It is a collection of papers describing novel results in electrodeposition biocoatings, which will be of interest for many scholars and researcher

Smart dressings based on bacterial cellulose for chronic wounds healing and monitoring

In recent years, there has been an upward trend for novel biomass based green materials for dressing chronic wounds, which can assist in wound healing and monitoring. This research focuses on candidate components for smart chronic wound dressings based on bacterial cellulose (BC), which is comprised of two parts: antimicrobial BC nanocomposites for wound dressing, and a BC-derived pH sensor for monitoring chronic wounds. This research demonstrates a novel ability to utilise BC and BC-derived nanocomposites in potential applications for smart wound dressings. In the chapter regarding BC production, samples grown in static from four different Acetobacter bacterial strains are characterized and compared for the first time. SEM and BET results demonstrate a large surface area (>100 m2/g) and XRD analysis reveals high crystallinity (>60%). In vitro cell tests indicate potential biocompatibility. In the BC based pH sensor chapter, a pyrolyzed BC (p-BC) aerogel was incorporated with polyaniline (PANI) and polydimethylsiloxane (PDMS), exhibiting near-Nernst pH sensitivity (50.4 mV/pH). In the chapter on antimicrobial BC nanocomposites, the inorganic BC/silver nanoparticle (BC/AgNP) and organic BC/lysozyme, BC/eggshell membrane (BC/ESM), BC/methylglyoxal (BC/MGO) nanocomposites were fabricated and characterized, with BC/ESM and BC/MGO nanocomposites proposed for the first time. The antimicrobial properties were tested via a disk diffusion method, with BC/MGO exhibiting the greatest antimicrobial activity, with diameters of inhibition zone (DIZ) up to 17.1 ± 0.6 mm against S. aureus and 15.5 ± 0.5 mm against E. coli. Tensile tests show the nanocomposites still retain the high tensile strength of plain BC (>2 MPa). These results indicate that BC and BC-derived nanocomposites are promising candidate materials for smart wound dressings. The future work will focus on more detailed in vitro biocompatibility tests and in vivo wound healing assays

Carbon-Based Nanomaterials for (Bio)Sensors Development

Carbon-based nanomaterials have been increasingly used in sensors and biosensors design due to their advantageous intrinsic properties, which include, but are not limited to, high electrical and thermal conductivity, chemical stability, optical properties, large specific surface, biocompatibility, and easy functionalization. The most commonly applied carbonaceous nanomaterials are carbon nanotubes (single- or multi-walled nanotubes) and graphene, but promising data have been also reported for (bio)sensors based on carbon quantum dots and nanocomposites, among others. The incorporation of carbon-based nanomaterials, independent of the detection scheme and developed platform type (optical, chemical, and biological, etc.), has a major beneficial effect on the (bio)sensor sensitivity, specificity, and overall performance. As a consequence, carbon-based nanomaterials have been promoting a revolution in the field of (bio)sensors with the development of increasingly sensitive devices. This Special Issue presents original research data and review articles that focus on (experimental or theoretical) advances, challenges, and outlooks concerning the preparation, characterization, and application of carbon-based nanomaterials for (bio)sensor development