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Biointerfaces are significantly affected by electrolytes according to the Hofmeister series. This work reports a systematic investigation on the effect of different metal chlorides, sodium and potassium bromides, iodides and thiocyanates, on the ESI/MS spectra of bovine serum albumin (BSA) in aqueous solution at pH = 2.7. The concentration of each salt was varied to maximize the quality of the ESI/MS spectrum, in terms of peak intensity and bell-shaped profile. The ESI/MS spectra of BSA in the absence and in the presence of salts showed a main protein pattern characterized by the expected mass of 66.5 kDa, except the case of BSA/RbCl (mass 65.3 kDa). In all systems we observed an additional pattern, characterized by at least three peaks with low intensity, whose deconvolution led to suggest the formation of a BSA fragment with a mass of 19.2 kDa. Only NaCl increased the intensity of the peaks of the main BSA pattern, while minimizing that of the fragment. NaCl addition seems to play a crucial role in stabilizing the BSA ionized interface against hydrolysis of peptide bonds, through different synergistic mechanisms. To quantify the observed specific electrolyte effects, two "Hofmeister" parameters (H s and P s ) are proposed. They are obtained using the ratio of (BSA-Salt)/BSA peak intensities for both the BSA main pattern and for its fragment. SYNOPSIS: NaCl stabilizes BSA ion and almost prevents fragmentation due to denaturing pH., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

We examine Hofmeister specific ion effects of electrolytes added to protein solution under conditions minimizing electrostatic attraction between cations and positively charged protein. Hemoglobin (Hb) in aqueous solution at the denaturing pH = 2.7 is investigated in the presence of several metal chlorides, along with sodium and potassium bromides, iodides and thiocyanates, using electrospray ionization mass spectrometry (ESI-MS). Salt concentration was varied to maximize peak intensity and bell-shaped profile in the ESI-MS spectrum. The α-chain of myoglobin is identified as the main pattern of the ESI-MS spectra in all Hb-salt systems. Both peak intensity and quality of the bell-shaped profile of the protein spectrum decrease in the cation order: K + > > Mg 2+  > Li + > > Na +  > Ca 2+  ≈ Cs +  > Rb + for Hb-Metal Chloride systems, and decrease in the anion order: Cl -  > Br -  > I -  > SCN - for systems of both Hb-NaX and Hb-KX salts. To quantify salt addition effects two Hofmeister specific electrolyte parameters H S , and P S are proposed. H S is the mean (Hb-salt)/Hb peak intensity ratio, measured for the nine peaks used for ESI-MS spectra deconvolution, taken at the same m/z values of the Hb profile. P S is the ratio between H S standard deviation and H S , and provides a specific perturbation parameter measuring the loss of protein structure. These two Hofmeister parameters give clear evidence of the effects induced either by KCl, MgCl 2 and LiCl that enhance protein peak intensity, or by NaBr, NaI, NaSCN and KSCN that induce the protein fragmentation, due to electrolyte-mediated dissociation., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Mesoporous silica nanoparticles (MSNs) were functionalized with amino groups (MSN-NH 2 ) and then with hyaluronic acid, a biocompatible biopolymer which can be recognized by CD44 receptors in tumor cells, to obtain a targeting drug delivery system. To this purpose, three hyaluronic acid samples differing for the molecular weight, namely HA S (8-15 kDa), HA M (30-50 kDa) and HA L (90-130 kDa), were used. The MSN-HA S , MSN-HA M , and MSN-HA L materials were characterized through zeta potential and dynamic light scattering measurements at pH = 7.4 and T = 37 °C to simulate physiological conditions. While zeta potential showed an increasing negative value with the increase of the HA chain length, an anomalous value of the hydrodynamic diameter was observed for MSN-HA L , which was smaller than that of MSN-HA S and MSN-HA M samples. The cellular uptake of MSN-HA samples on HeLa cells at 37 °C was studied by optical and electron microscopy. HA chain length affected significantly the cellular uptake that occurred at a higher extent for MSN-NH 2 and MSN-HA S than for MSN-HA M and MSN-HA L samples. Cellular uptake experiments carried out at 4 °C showed that the internalization process was inhibited for MSN-HA samples but not for MSN-NH 2 . This suggests the occurrence of two different mechanisms of internalization. For MSN-NH 2 the uptake is mainly driven by the attractive electrostatic interaction with membrane phospholipids, while MSN-HA internalization involves CD44 receptors overexpressed in HeLa cells., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Lipid based formulations, endowed of long term stability as a result of the formation of lamellar liquid crystals, were prepared using the natural lipids lecithin and glycerol trioleate in water, and characterized using optical microscopy, SAXRD and NMR. The formulations, designed as possible carriers for lysozyme and caffeine, were evaluated for structural features and stability after the loading of the guest molecules. Release experiments were performed at 37 °C using the PBS medium. No burst release was observed either for lysozyme or caffeine. Although lysozyme released from the lipid formulations does not fully retain its biological activity, the investigated liquid crystal stabilized formulations display a promising potential as drug and cosmetic carriers for topical applications, due to their high biocompatibility., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A dynamic, rheological, and structural characterization of aqueous gel-like systems containing hydroxypropyl guar gum (HPG), borax and glycerol is presented in this paper. The role of glycerol, which is introduced as a plasticizer in the formulation, is investigated by means of 11 B NMR and 1 H NMR PGSTE measurements in order to clarify its contribution to the gel network formation and its interaction with borax, with whom it forms a complex. The effect of gels components on the rheological behaviour and on the activation energy related to the relaxation process of the system was assessed by means of rheology. The results obtained suggest that the mechanical properties of these gels can be tuned and controlled by modulating the formulation in a wide range of compositions. Moreover, a structural characterisation has been also carried out by means of Small Angle X-ray Scattering (SAXS) to highlight the role of the various components on the mesh size of the network. The structural and mechanical characteristics of these systems suggest their potential use for applicative purposes. In this regard, one of the gel set up has been successfully tested as cleaning agent on the surface of a XIX stucco fragment coming from the La Fenice theatre (Venice, Italy) for the removal of a dirt layer composed by dust and particulated matter originated during a fire in 1996., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This short review highlights the effect of electrolytes on the performance of proteins-mesoporous silica conjugates which can open interesting perspectives in biotechnological fields, particularly nanomedicine and biocatalysis. Indeed therapeutic proteins and peptides represent a challenging innovation for several kinds of diseases, but since their self-life in biological fluids is very short, they need a stealth protective carrier. Similarly, enzymes need a solid support to improve thermal stability and to allow for recycling. Ordered mesoporous silica materials represent a valid choice as widely demonstrated. Both proteins and silica mesoporous materials possess charged surfaces, and here, the crucial role of pH, buffer, ionic strength and electrolyte type is posed in relation with loading/release of proteins onto/from the silica support through the analysis of adsorption and release processes. A delicate interplay of electrostatic and van der Waals interactions arises from considering electrolytes' effects on the two different charged surfaces. Clear outcomes concern the effect of pH and ionic strength. Protein loading onto the silica matrix is favored by an adsorbing solution having a pH close to the protein pI, and by a high ionic strength that reduces the Debye length. Release is instead favored by an adsorbing solution characterized by an intermediate ionic strength, close to the physiological values. Significant specific ions effects are shown to affect both proteins and silica matrices, as well as protein adsorption onto silica matrices. Further work is needed to quantify specific ion effects on the preservation of the biological activity, and on the release performance., (Copyright © 2015 Elsevier B.V. All rights reserved.)

We present here an innovative, fluorescent, monoolein-based cubosome dispersion. Rather than embedded within the monoolein palisade, the fluorescent imaging agent, namely dansyl, was conjugated to the terminal ethylene oxide moieties of the block copolymer Pluronic F108. We discuss the physicochemical and photophysical properties of this fluorescent Pluronic and of a cubosome formulation stabilized by a mixture of dansyl-conjugated and non-conjugated Pluronic, also including an anticancer drug (quercetin). Furthermore, we performed biocompatibility tests against HeLa cells to assess internalization and cytotoxicity features of this nanoparticles aqueous dispersion. Cryo-TEM, SAXS, and DLS analysis, proved the bicontinuous cubic inner nanostructure and the morphology of this fluorescent cubosome dispersion, while photophysical measurements and biocompatibility results basically validate their potential use for theranostic nanomedicine applications., (Copyright © 2015 Elsevier B.V. All rights reserved.)

This review highlights the key role of NMR techniques in demonstrating the molecular aspects of the self-assembly of surfactant molecules that nowadays constitute the basic knowledge which modern nanoscience relies on. The aim is to provide a tutorial overview. The story of a rigorous scientific approach to understand self-assembly in surfactant systems and biological membranes starts in the early seventies when the progresses of SAXRD and NMR technological facilities allowed to demonstrate the existence of ordered soft matter, and the validity of Tanford approach concerning self-assembly at a molecular level. Particularly, NMR quadrupolar splittings, NMR chemical shift anisotropy, and NMR relaxation of dipolar and quadrupolar nuclei in micellar solutions, microemulsions, and liquid crystals proved the existence of an ordered polar-apolar interface, on the NMR time scale. NMR data, rationalized in terms of the two-step model of relaxation, allowed to quantify the dynamic aspects of the supramolecular aggregates in different soft matter systems. In addition, NMR techniques allowed to obtain important information on counterion binding as well as on size of the aggregate through molecular self-diffusion. Indeed NMR self-diffusion proved without any doubt the existence of bicontinuous microemulsions and bicontinuous cubic liquid crystals, suggested by pioneering and brilliant interpretation of SAXRD investigations. Moreover, NMR self-diffusion played a fundamental role in the understanding of microemulsion and emulsion nanostructures, phase transitions in phase diagrams, and particularly percolation phenomena in microemulsions. Since the nineties, globalization of the knowledge along with many other technical facilities such as electron microscopy, particularly cryo-EM, produced huge progresses in surfactant and colloid science. Actually we refer to nanoscience: bottom up/top down strategies allow to build nanodevices with applications spanning from ICT to food technology. Developments in the applied fields have also been addressed by important progresses in theoretical skills aimed to understand intermolecular forces, and specific ion interactions. Nevertheless, this is still an open question. Our predictive ability has however increased, hence more ambitious targets can be planned. Nanomedicine represents a major challenging field with its main aims: targeted drug delivery, diagnostic, theranostics, tissue engineering, and personalized medicine. Few recent examples will be mentioned. Although the real applications of these systems still need major work, nevertheless new challenges are open, and perspectives based on integrated multidisciplinary approaches would enable both a deeper basic knowledge and the expected advances in biomedical field., (© 2013.)