Calcium phosphate particles coated with humic substances: A potential plant biostimulant from circular economy

Nowadays, the use of biostimulants to reduce agrochemical input is a major trend in agriculture. In this work, we report on calcium phosphate particles (CaP) recovered from the circular economy, combined with natural humic substances (HSs), to produce a plant biostimulant. CaPs were obtained by the thermal treatment of Salmo salar bones and were subsequently functionalized with HSs by soaking in a HS water solution. The obtained materials were characterized, showing that the functionalization with HS did not sort any effect on the bulk physicochemical properties of CaP, with the exception of the surface charge that was found to get more negative. Finally, the effect of the materials on nutrient uptake and translocation in the early stages of development (up to 20 days) of two model species of interest for horticulture, Valerianella locusta and Diplotaxis tenuifolia, was assessed. Both species exhibited a similar tendency to accumulate Ca and P in hypogeal tissues, but showed different reactions to the treatments in terms of translocation to the leaves. CaP and CaP\u2013HS treatments lead to an increase of P accumulation in the leaves of D. tenuifolia, while the treatment with HS was found to increase only the concentration of Ca in V. locusta leaves. A low biostimulating effect on both plants\u2019 growth was observed, and was mainly scribed to the low concentration of HS in the tested materials. In the end, the obtained material showed promising results in virtue of its potential to elicit phosphorous uptake and foliar translocation by plants

On the use of superparamagnetic hydroxyapatite nanoparticles as an agent for magnetic and nuclear in vivo imaging

The identification of alternative biocompatible magnetic NPs for advanced clinical application is becoming an important need due to raising concerns about iron accumulation in soft issues associated to the administration of superparamagnetic iron oxide nanoparticles (NPs). Here, we report on the performance of previously synthetized iron-doped hydroxyapatite (FeHA) NPs as contrast agent for magnetic resonance imaging (MRI). The MRI contrast abilities of FeHA and Endorem® (dextran coated iron oxide NPs) were assessed by 1H nuclear magnetic resonance relaxometry and their performance in healthy mice was monitored by a 7 Tesla scanner. FeHA applied a higher contrast enhancement, and had a longer endurance in the liver with respect to Endorem® at iron equality. Additionally, a proof of concept of FeHA use as scintigraphy imaging agent for positron emission tomography (PET) and single photon emission computed tomography (SPECT) was given labeling FeHA with 99mTc-MDP by a straightforward surface functionalization process. Scintigraphy/x-ray fused imaging and ex vivo studies confirmed its dominant accumulation in the liver, and secondarily in other organs of the mononuclear phagocyte system. FeHA efficiency as MRI-T2 and PET-SPECT imaging agent combined to its already reported intrinsic biocompatibility qualifies it as a promising material for innovative nanomedical applications. STATEMENT OF SIGNIFICANCE: The ability of iron-doped hydroxyapatite nanoaprticles (FeHA) to work in vivo as imaging agents for magnetic resonance (MR) and nuclear imaging is demonstrated. FeHA applied an higher MR contrast in the liver, spleen and kidneys of mice with respect to Endorem®. The successful radiolabeling of FeHA allowed for scintigraphy/X-ray and ex vivo biodistribution studies, confirming MR results and envisioning FeHA application for dual-imaging

Determination of collagen by pyrolysis/GC-MS. Evaluation of the degree of conservation of archeological bones from Vicenne (Italy) by comparison with XRD, TGA and FTIR analysis

Human bones and teeth are frequently recovered at archaeological sites. Their state of preservation may depend on the mode and the burial environment. The content of collagen and the degree of crystallinity of carbonate hydroxyapatite (HA) are among the indicators adopted to evaluate the conservation status of bones. Analytical pyrolysis (Py) [1] together with X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA), were used at this scope. In this work, a new quantitative procedure in Py was employed to characterise residual proteins in five bone samples from the medieval necropolis of Vicenne-Campochiaro (Molise, Italy)[2]. The yields of cyclic dipeptides (2,5-diketopiperazines, DKPs) evolved form the pyrolysis of the samples, including the cyclo(proline-hydoxyproline) as distinctive marker of collagen, were determined by GC-MS with and without silylation. The detection of DKPs enabled the identification of collagen in all the analysed samples, in accordance to the FTIR spectra showing the characteristic amide peak. The presence of organic matter along with that of carbonatic phases was confirmed and estimated by TGA. XRD data showed that the samples mainly contained HA having different degrees of crystallinity; small amounts of quartz and calcite were also detected in some samples. The quantitative experimental data were combined to provide a relative estimate of the degree of conservation of the bone samples. The bones of an adult young female (t.139) and an aged male (t.165) resulted to be the worst and best preserved, respectively. The tombs were located in the same area where the acidity of the soil has damaged nearly all the skeletons. The skeleton from t.165 was almost complete, whereas the one from t.139 was lacking in many bones. Therefore biological (age-at-death, sex) and ritual (care, depth) factors as well as specific conditions of each burial could be involved in the observed different preservation state

Bio-oils from biomass slow pyrolysis: a chemical and toxicological screening

Bio-oils were produced from bench-scale slow-pyrolysis of three different biomass samples (corn stalks, poplar and switchgrass). Experimental protocols were developed and applied in order to screen their chemical composition. Several hazardous compounds were detected in the bio-oil samples analysed, including phenols, furans and polycyclic aromatic hydrocarbons. A procedure was outlined and applied to the assessment of toxicological and carcinogenic hazards of the bio-oils. The following hazardous properties were considered: acute toxicity; ecotoxicity; chronic toxicity; carcinogenicity. Parameters related to these properties were quantified for each component identified in the bio-oils and overall values were estimated for the bio-oils. The hazard screening carried out for the three bio-oils considered suggested that: i) hazards to human health could be associated with chronic exposures to the bio-oils; ii) acute toxic effects on humans and eco-toxic effects on aquatic ecosystems could also be possible in the case of loss of containment; and iii) bio-oils may present a marginal potential carcinogenicity. The approach outlined allows the collection of screening information on the potential hazards posed by the bio-oils. This can be particularly useful when limited time and analytical resources reduce the possibility to obtain detailed specific experimental data

Magnetic calcium phosphates nanocomposites for the intracellular hyperthermia of cancers of bone and brain

Magnetic hyperthermia is limited by the low selective susceptibility of neoplastic cells interspersed within healthy tissues, which we aim to improve on. Materials & methods: Two superparamagnetic calcium phosphates nanocomposites, that is, iron-doped hydroxyapatite and iron oxide (Mag) nanoparticles coated with amorphous calcium phosphate (Mag@CaP), were synthesized and tested for selective activity against brain and bone cancers. Results: Nanoparticle uptake and intracellular localization were prerequisites for reduction of cancer viability in alternate magnetic fields of extremely low power. Sheer adsorption onto the outer membrane was not sufficient to produce this effect, which was extremely significant for Mag@CaP and iron-doped hydroxyapatite, but negligible for Mag, demonstrating benefits of combining magnetic iron with calcium phosphates. Conclusion: Such selective effects are important in the global effort to rejuvenate clinical prospects of magnetic hyperthermia

Magnetic Labelling of Mesenchymal Stem Cells with Iron-Doped Hydroxyapatite Nanoparticles as Tool for Cell Therapy

Superparamagnetic nanoparticles offer several opportunities in nanomedicine and magnetic cell targeting. They are considered to be an extremely promising approach for the translation of cell-based therapies from the laboratory to clinical studies. In fact, after injection, the magnetic labeled cells could be driven by a static magnetic field and localized to the target site where they can perform their specific role. In this study, innovative iron-doped hydroxyapatite nanoparticles (FeHA NPs) were tested with mesenchymal stem cells (MSCs) as tools for cell therapy. Results showed that FeHA NPs could represent higher cell viability in'respect to commercial superparamagnetic iron oxide nanoparticles (SPION) at four different concentrations ranging from 10 \u3bcg/ml up to 200 \u3bcg/ml and would also upregulate an early marker involved in commitment and differentiation of MSCs. Moreover, FeHA NPs were uptaken without negatively affecting the cell behavior and their ultrastructure. Thus obtained magnetic cells were easily guided by application of a static magnetic field. This work demonstrates the promising opportunities of FeHA NPs in MSCs labeling due to the unique features of fast degradation and very low iron content of FeHA NPs compared to SPIONs. Likewise, due to the intrinsic properties of FeHA NPs, this approach could be simply transferred to different cell types as an effective magnetic carrier of drugs, growth factors, miRNA, etc., offering favorable prospects in nanomedicin

Calcium phosphate nanoparticle precipitation by a continuous flow process: A design of an experiment approach

Calcium phosphate nanoparticles (CaP NPs) are an efficient class of nanomaterials mainly used for biomedical applications but also very promising in other sectors such as cosmetics, catalysis, water remediation, and agriculture. Unfortunately, as in the case of other nanomaterials, their wide application is hindered by the difficulty to control size, morphology, purity and degree of particle aggregation in the translation from laboratory to industrial scale production that is usually carried out in batch or semi-batch systems. In this regard, the use of continuous flow synthesis can help to solve this problem, providing more homogenous reaction conditions and highly reproducible synthesis. In this paper, we have studied with a design of experiment approach the precipitation of citrate functionalized CaP NPs aided by sonication using a continuous flow wet chemical precipitation, and the effect of some of the most relevant process factors (i.e., reactant flow rate, sonication amplitude, and maturation time) on the physico-chemical properties of the NPs were evaluated. From the statistical data analysis, we have found that CaP NP dimensions are influenced by the reactor flow rate, while the crystalline domain dimensions and product purity are influenced by the maturation process. This work provides a deeper understanding of the relationships between reaction process factors and CaP NP properties, and is a relevant contribution for the scale-up production of CaP NPs for nanomedical or other applications

Role of Diisocyanate Structure on Self-Healing and Anticorrosion Properties of Waterborne Polyurethane Coatings

Organic coatings are extensively investigated as possible solution to prevent or at least retard the occurring of corrosion processes on metal surfaces. Their actual breakthrough is still hampered by the risk of barrier properties loss because of local failure of the coating integrity. To address this issue, self-healing coatings, which are intrinsically able to recover from damages upon exposure to external stimuli, are currently gaining increasing attention. Herein, waterborne polyurethanes (PU) are synthesized, and a Diels–Alder adduct is added into the polymeric backbone to endow the material with self-healing functionality. The effect of different diisocyanate in PU synthesis is explored, namely isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate (HMDI), and hexamethylene diisocyanate. The obtained results highlight the key role of the interactions among soft and hard segments in ultimately defining the coating performances. Actually, the combination of Fourier transform infrared spectroscopy, atomic force microscopy and X-ray diffration analysis reveals that the HMDI-based PU have showed the best balance in terms of H-bonding strength among hard segments and crystallinity degree in the soft ones. This allows to reach a good compromise in terms of mechanical resistance, anticorrosion properties, and self-healing ability