The recovery and conversion of Extracellular Polymeric Substances (EPS) from sewage sludge into bio-based commodities might improve the economics and environmental sustainability of wastewater ...treatment. This contribution explores the application of EPS from anammox granular waste sludge as biosorbent for the removal of heavy metals, specifically lead, copper, nickel, and zinc. Adsorption capacities equivalent or higher than well-established adsorbent media emerged from single-metal biosorption studies (up to 84.9, 52.8, 21.7 and 7.4 mg/gTSEPS for Pb2+, Cu2+, Ni2+ and Zn2+, respectively). Combining spectroscopic techniques, a mechanistic hypothesis for metal biosorption, based on a combination of electrostatic interaction, ion exchange, complexation, and precipitation, was proposed. The adsorption mechanisms of extracted EPS and non-extracted EPS in the native biomass were indirectly compared by means of single-metal biosorption studies performed with pristine granules (adsorbing up to 103.7, 36.1, 48.2 and 49.8 mg/gTSgranules of Pb2+, Cu2+, Ni2+, and Zn2+, respectively). In comparison with pristine anammox granules, EPS showed lower adsorption capacities except for copper and different adsorption pathways as postulated based on the adsorption data interpretation via theoretical models. The multi-metal biosorption tests excluded significant competitions among different heavy metals for the EPS binding sites, thus opening further scenarios for the treatment of complex wastewaters.
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•EPS from anammox granular sludge were valorized as heavy metal biosorbent.•Anammox EPS featured metal-binding capacities higher than common adsorbent media.•Anammox granules and extracted EPS followed different biosorption pathways.•A multifaceted mechanism led to the heavy metal biosorption by anammox EPS.
The composition and colloidal properties of extracellular polymeric substances (EPS) from anammox granular sludge were investigated through a complete set of spectroscopic and scattering techniques. ...To fully characterize EPS, we developed a robust and reproducible extraction/recovery protocol specific for anammox biofilms, based on the change of water affinity under alternated alkaline and acidic conditions, each monitored with Z-potential and dynamic light scattering analysis. This method enabled both extraction as a colloidal suspension and recovery as a solid of large amounts of EPS (0.38 ± 0.04 and 0.21 ± 0.02 g/g, respectively), including for the first time its structural components. The dominance of the proteinaceous fraction was revealed by all methods tested, resulting in the highest protein/carbohydrates ratio reported for biofilms applied in the wastewater sector. The abundance of proteinaceous ordered structures and in particular of cross-β motifs was detected, indicating for the first time the presence of amyloid-like aggregates in anammox EPS, and suggesting the key role of the protein fraction in determining the mechanical properties of the parent biofilm. The robustness and reproducibility of the proposed method fill the current gap towards a reliable full-scale recovery as well as towards an accurate and meaningful investigation of anammox EPS and pave the way for further exploration of their applicative potential thus stimulating the desirable shift from the current wastewater treatment perspective towards biorefinery in a circular economy context.
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•Novel and robust method for the extraction and recovery of (structural) anammox EPS.•Highest reported extraction and recovery yields of 38 and 21%, respectively.•Proteins as main fraction (>60%) with prevalence of ordered secondary structures.•Novel observation of the abundance of amyloid-like cross-β structures.
Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar ...structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H
O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV-vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.
Increasing amounts of engineered nanomaterials such as TiO
2
and CeO
2
are released into air, waters, soils, and sediments. However, assessing the human-made origin of those nanomaterials is rather ...difficult because Ti- and Ce-rich particles are naturally present in soils and sediments at concentrations typically much higher than estimated concentrations of engineered nanomaterials. In addition, analysis is complicated by the interactions and aggregation of nanoparticles with environmental particles. Therefore, more knowledge on the properties of natural nanomaterials is needed to distinguish engineered nanomaterials in natural systems. Here, we extracted soil nanomaterials with six extractants and compared recovery and disaggregation to primary particles. Nanomaterials were characterized for hydrodynamic diameter and zeta potential by dynamic light scattering, size-based elemental distribution by field-flow fractionation coupled with inductively coupled plasma-mass spectroscopy, and morphology by transmission electron microscopy. Results show that nanomaterial concentrations increased from CH
3
COOH–NaCl–water (lowest), to water or NaCl–water, Na
2
CO
3
, Na
4
P
2
O
7
, and NaCl–Na
4
P
2
O
7
(highest). Na
4
P
2
O
7
was the most efficient extractant that induced the release of primary nanomaterials from microaggregates. Although sodium carbonate extracted relatively high concentrations of nanomaterials, the extracted nanomaterials occurred mainly as aggregates of primary nanomaterials. Ultrapure water, sodium chloride and acetic acid resulted in poor nanomaterial extraction and broad size distributions. Elemental ratios illustrate that Ti is associated with Nb, Ta, and V, and that Ce is associated with rare earth elements such as La, Eu, Y, Ho, Er, Tm, and Yb. Our findings indicate that size, size distribution, and elemental ratios can be used as fingerprints to differentiate engineered nanomaterials such as TiO
2
and CeO
2
from natural nanomaterials in complex media.
Extracellular Vesicles (EVs) – cell secreted vesicles that carry rich molecular information of the parental cell and constitute an important mode of intercellular communication – are becoming a ...primary topic in translational medicine. EVs (that comprise exosomes and microvesicles/microparticles) have a size ranging from 40 nm to 1 μm and share several physicochemical proprieties, including size, density, surface charge, and light interaction, with other nano-objects present in body fluids, such as single and aggregated proteins. This makes separation, titration, and characterization of EVs challenging and time-consuming. Here we present a cost-effective and fast colorimetric assay for probing by eye protein contaminants and determine the concentration of EV preparations, which exploits the synergy between colloidal gold nanoplasmonics, nanoparticle–protein corona, and nanoparticle–membrane interaction. The assay hits a limit of detection of protein contaminants of 5 ng/μL and has a dynamic range of EV concentration ranging from 35 fM to 35 pM, which matches the typical range of EV concentration in body fluids. This work provides the first example of the exploitation of the nanoparticle–protein corona in analytical chemistry.
In the past decade(s), fluorescence microscopy and laser scanning confocal microscopy (LSCM) have been widely employed to investigate biological and biomimetic systems for pharmaceutical ...applications, to determine the localization of drugs in tissues or entire organisms or the extent of their cellular uptake (in vitro). However, the diffraction limit of light, which limits the resolution to hundreds of nanometers, has for long time restricted the extent and quality of information and insight achievable through these techniques. The advent of super-resolution microscopic techniques, recognized with the 2014 Nobel prize in Chemistry, revolutionized the field thanks to the possibility to achieve nanometric resolution, i.e., the typical scale length of chemical and biological phenomena. Since then, fluorescence microscopy-related techniques have acquired renewed interest for the scientific community, both from the perspective of instrument/techniques development and from the perspective of the advanced scientific applications. In this contribution we will review the application of these techniques to the field of drug delivery, discussing how the latest advancements of static and dynamic methodologies have tremendously expanded the experimental opportunities for the characterization of drug delivery systems and for the understanding of their behaviour in biologically relevant environments.
Hybrid materials composed of superparamagnetic iron oxide nanoparticles (SPIONs) and lipid self-assemblies possess considerable applicative potential in the biomedical field, specifically, for ...drug/nutrient delivery. Recently, we showed that SPIONs-doped lipid cubic liquid crystals undergo a cubic-to-hexagonal phase transition under the action of temperature or of an alternating magnetic field (AMF). This transition triggers the release of drugs embedded in the lipid scaffold or in the water channels. In this contribution, we address this phenomenon in depth, to fully elucidate the structural details and optimize the design of hybrid multifunctional carriers for drug delivery. Combining small-angle X-ray scattering (SAXS) with a magnetic characterization, we find that, in bulk lipid cubic phases, the cubic-to-hexagonal transition determines the magnetic response of SPIONs. We then extend the investigation from bulk liquid-crystalline phases to colloidal dispersions, i.e., to lipid/SPIONs nanoparticles with cubic internal structure ("magnetocubosomes"). Through Synchrotron SAXS, we monitor the structural response of magnetocubosomes while exposed to an AMF: the magnetic energy, converted into heat by SPIONs, activates the cubic-to-hexagonal transition, and can thus be used as a remote stimulus to spike drug release "on-demand". In addition, we show that the AMF-induced phase transition in magnetocubosomes steers the realignment of SPIONs into linear string assemblies and connect this effect with the change in their magnetic properties, observed at the bulk level. Finally, we assess the internalization ability and cytotoxicity of magnetocubosomes in vitro on HT29 adenocarcinoma cancer cells, in order to test the applicability of these smart carriers in drug delivery applications.
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•A new microemulsion is proposed for the removal of polymers from wall paintings.•The system is based on DDAO, which is a safe and eco-compatible surfactant.•Through SANS analyses, ...the nanostructure of the cleaning system was investigated.•The H2O/DDAO/diethyl carbonate system was successfully used to remove PrimalAC33.•Cleaning tests on archeological Maya wall paintings further confirmed its effectiveness.
Surfactant-based aqueous fluids, such as micellar solutions and microemulsions, are effective, safe and selective media for cleaning operations in conservation of cultural heritage. The search for better-performing systems and eco-friendly cleaning systems is currently a major goal in conservation science. We report here on a ternary o/w microemulsion, composed of diethyl carbonate (DC) as the oil phase and N,N-Dimethyldodecan-1-amine oxide (DDAO) as the surfactant. DDAO is a well known and widely used detergent and solubilizing agent, selected here for its degradability and eco-compatibility. Due to its nonionic/cationic nature, it can be used also when nonionic-based formulations become ineffective because of clouding and phase separation. Moreover, DDAO is insensitive to the presence of divalent metal ions, usually abundant in wall paintings substrates. Small-Angle Neutron Scattering (SANS) provided detailed information about the nanostructure of the surfactant aggregates. Finally, the cleaning effectiveness of the nanofluid was assessed both on fresco mock-ups and on real wall paintings conserved in the archeological site of Tulum, Mexico. Here, conservators successfully used the microemulsion to remove naturally aged films of complex polymer mixtures from the works of art surface.
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