Synthesis and Characterization of Functional Inorganic Nano-Micro Particles and their Role in Innovative Practical Applications

In this thesis, the synthesis of nano-micro particles of crystalline inorganic materials and four different applications involving their use, are presented . Inorganic particles have been synthesized following two main criteria: i) the particle’s dimensions, specific surface area and crystalline phase of the product have been optimized for the practical application; ii) both the synthesis and application should be based on a simple procedure, environmental low impact, economical affordability. In particular, Titanium dioxide nanoparticles have been synthesized by sol-gel hydrolysis of Titanium(IV) isopropoxide in an isopropyl alcohol/water solution. The isopropyl alcohol contained in the solvent mixture act as a capping agent stabilizing the forming nanometric particles, and play also a role in the suspension stability. Synthesized Titanium dioxide reveals good photocatalytic properties directly as synthesized, without needing further thermal treatment. Photoactive Titanium dioxide have been used for NOx pollutants abatement on waste gases produced by a working plant and as self-cleaning coating on photovoltaic Silicon panels, showing good results. Crystalline calcium phosphate nano and micro particles, in particular Hydroxyapatite, Brushite, Monetite and Mg-doped β-Tricalcium phosphate have been synthesized. Two applications of the synthesized Calcium phosphates are reported, both based on the drug delivery concept. Hydroxyapatite nanocrystals were used to adsorbe and retain on their surface anticancer drugs based on a Platinum complex, and release them in response to a pH variation. Phytotherapics active elements have been stabilized by physisorption on Calcium phosphates particles surface. The administration of the obtained suspensions shows good results in terms of plant’s healing, using a lower amount of phytotherapic elements compared to the commercial products.In questa tesi sono riportate sintesi e caratterizzazione di nano-micro particelle di materiale cristallino inorganico, e quattro loro applicazioni. Le particelle inorganiche sono state preparate seguendo due criteri principali: i) le proprietà chimico-fisiche delle particelle devono essere ottimizzate in funzione dell’applicazione; ii) sintesi e applicazione devono essere basate su procedure semplici, con basso impatto ambientale ed economicamente sostenibili. In particolare, nano particelle di Titanio biossido sono state sintetizzate tramite reazione di idrolisi di Titanio(IV) isopropossido in una soluzione di acqua a alcol isopropilico. L’alcol isopropilico presente nella miscela di solventi agisce da agente cappante stabilizzando le nanoparticelle in formazione e dimostra un ruolo nella stabilità della sospensione. Il Titanio biossido prodotto ha rivelato buone proprietà foto catalitiche senza bisogno di ulteriori trattamenti termici. Il Titanio biossido foto attivo è stato applicato con buoni risultati nell’abbattimento di NOx dalle emissioni di uno stabilimento e come strato autopulente su dei pannelli fotovoltaici. Sono state sintetizzate nano e micro particelle di calcio fosfati cristallini, nello specifico Idrossiapatite, Brushite, Monetite and β-Tricalcio fosfato Mg-sostituito. Ne sono riportate due applicazioni, entrambe basate sul concetto di drug delivery. Nanocristalli di Idrossiapatite sono stati utilizzati per adsorbire e ritenere sulla loro superficie farmaci chemioterapici basati su complessi di Platino, e successivamente rilasciare il farmaco in risposta ad una variazione di pH. Alcuni principi attivi fitoterapici sono stai stabilizzati tramite fisisorbimento sulla superficie di particelle di Calcio fosfati in sospensione. La loro applicazione ha dimostrato buoni risultati curativi sulle piante, utilizzando quantitativi di principio attivo molto ridotti rispetto ai prodotti commerciali

Effect of Storage Conditions and Time on the Polyphenol Content of Wheat Flours

Whole wheat flour possesses many nutritional properties because of its abundant bioactive components which are affected by cultivar, but little attention is paid to its relationship with storage conditions. In this study, phenolic extracts of whole wheat flour from four cultivars stored under different conditions (aerated and under vacuum) and different times (0, 2, 4, 8 weeks) were obtained. The total polyphenol (TPC) and flavonoid (TFC) contents, composition of phenolic acids, and antioxidant activities (AA) of phenolic extracts were evaluated. The results showed that Verna exhibited the highest levels of TPC, TFC, and AA for both storage conditions among the four cultivars. Moisture content, TFC, and AA fluctuated during storage. After 8 weeks, the TPC, TFC, and AA decreased with respect to Week 0 in all the cultivars. The TPC losses ranged between 16.39% and 20.88% and TFC losses from 14.08% to 31.18%. The AA losses were approximately 30% from the DPPH assay, but no significant losses were shown in the FRAP assay. However, these parameters were not distinctive between the two storage conditions. The wheat phenolic acid profiles were influenced more by storage time than storage conditions in all cultivars. Overall, the results validate the effect of the storage time on wheat polyphenol

Durable self-cleaning coatings for architectural surfaces by incorporation of TiO2 nano-particles into hydroxyapatite films

To prevent soiling of marble exposed outdoors, the use of TiO2 nano-particles has been proposed in the literature by two main routes, both raising durability issues: (i) direct application to marble surface, with the risk of particle leaching by rainfall; (ii) particle incorporation into inorganic or organic coatings, with the risk of organic coating degradation catalyzed by TiO2 photoactivity. Here, we investigated the combination of nano-TiO2 and hydroxyapatite (HAP), previously developed for marble protection against dissolution in rain and mechanical consolidation. HAP-TiO2 combination was investigated by two routes: (i) in series application of HAP followed by nano-TiO2 (“H+T”); (ii) simultaneous application by introducing nano-TiO2 into the phosphate solution used to form HAP (“HT”). The self-cleaning ability was evaluated before and after prolonged exposure to simulated rain. “H+T” and “HT” coatings exhibited much better resistance to nano-TiO2 leaching by rain, compared to TiO2 alone. In “H+T” samples, TiO2 nano-particles adhere better to HAP (having flower-like morphology and high specific surface area) than to marble. In “HT” samples, thanks to chemical bonds between nano-TiO2 and HAP, the particles are firmly incorporated in the HAP coating, which protects them from leaching by rain, without diminishing their photoactivity and without being degraded by them

Photocatalytic hydroxyapatite-titania nanocomposites for preventive conservation of marble

Soiling of external surfaces is an increasing issue for conservation of architectural heritage. Providing architectural surfaces with self-cleaning ability is one of the most promising routes of preventive conservation. To this aim, several methods have been proposed in the literature, based on the use of photocatalytic TiO2nanoparticles, either directly applied onto the surfaces or incorporated in protective coatings. However, when nano-TiO2is directly applied onto architectural surfaces, the particles are easily removed by rain. When TiO2is incorporated in polymeric coatings, durability issues arise as well, because the photoactivity of TiO2nanoparticles can promote degradation of the polymer. Here, we present an innovative alternative method, based on combination of TiO2nanoparticles and hydroxyapatite (HAP). The incorporation of nano-TiO2into an HAP coating protects the nanoparticles from leaching by rain, thanks to the chemical bonding between TiO2and HAP, without diminishing their photoactivity. As a result, marble treated with HAP-TiO2composites exhibits high self-cleaning ability and high durability, with results superior to those achieve by direct application of nano-TiO2onto the surface, as frequently performed on site

Health-promoting phytochemicals of stinging nettle (Urtica dioica L.) grown under organic farming in Italian environments

Urtica dioica L. (stinging nettle) is a neglected underutilized species, with potential as a future multi-purpose crop. To address the requisite for information on the influence of agronomical factors on health promoting bioactive components in leaf material under organic management, commercial stinging nettle was cultivated in three locations (Emilia Romagna, Italy) and analyzed over four harvests (September 2020 September 2021). Significantly higher levels of polyphenol and flavonoid components as well as antioxidant activity (ferric reducing antioxidant potential [FRAP] and 1,1-diphenyl-2-picrylhydrazyl [DPPH]) were obtainable in May and July in the second cultivation year. Only the location at Lizzano yielded significantly higher biomass in combination with higher polyphenol content and FRAP in May, DPPH in May and July and ascorbate in July and September. Throughout 2021, limiting water supply was the major determinant for the significantly lower yield and higher polyphenol (flavonoid) content, respectively, at the rainfed location of Tresigallo. Temperature and growing degree days were inversely correlated to polyphenol content and antioxidant activity, implicating temperature as the major determinant of the latter under non-limiting water supply in the mountainous region of Lizzano. Provided agronomic practices are implemented, including effective weed removal, uniform water supply (supplementary irrigation) and organic amendments, satisfactory yields are obtainable combined with high levels of bioactive components. This shows promise for stinging nettle cultivation towards increased use in the medicinal/herbalist sector

A quest for supramolecular gelators: silver(I) complexes with quinoline-urea derivatives

The quinoline urea derivatives 1,3-di(quinolin-5-yl) urea (DQ5U), 1-phenyl-3-(quinolin-6-yl) urea (PQ6U), 1-(isoquinolin-5-yl)-3-phenylurea (PiQ5U) and 1-phenyl-3-(3,5-bis(pyrid-2-yl)-1,2,4-triazol-4-yl) urea (PPT4U) have been synthesised and structurally characterized by powder and single crystal X-ray diffraction. Their gelator behaviour in the formation of Ag-complexes has been explored. Compound DQ5U proved capable of gelating the mixed solvent EtOH-DMF 1:2 (v/v) when mixed with 1 equivalent of AgNO3. In the case of PQ6U, two polymorphic forms of the complex [Ag(PQ6U)(2)]NO3, plus the solvated form [Ag(PQ6U)(2)]NO3 center dot CH3CN, were crystallized. Photophysical characterization of the ligands has been conducted in solution, while fluorescence microscopy has been used to examine the microstructure and photophysical properties of the gels formed by PQ5U and DQ5U with AgNO3