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Article ; Online: Vibrational Spectroscopy for In Vitro Monitoring Stem Cell Differentiation

Francesca Ravera / Esen Efeoglu / Hugh J. Byrne

Molecules, Vol 25, Iss 5554, p

2020 Volume 5554

Abstract: Stem cell technology has attracted considerable attention over recent decades due to its enormous potential in regenerative medicine and disease therapeutics. Studying the underlying mechanisms of stem cell differentiation and tissue generation is ... ...

Abstract	Stem cell technology has attracted considerable attention over recent decades due to its enormous potential in regenerative medicine and disease therapeutics. Studying the underlying mechanisms of stem cell differentiation and tissue generation is critical, and robust methodologies and different technologies are required. Towards establishing improved understanding and optimised triggering and control of differentiation processes, analytical techniques such as flow cytometry, immunohistochemistry, reverse transcription polymerase chain reaction, RNA in situ hybridisation analysis, and fluorescence-activated cell sorting have contributed much. However, progress in the field remains limited because such techniques provide only limited information, as they are only able to address specific, selected aspects of the process, and/or cannot visualise the process at the subcellular level. Additionally, many current analytical techniques involve the disruption of the investigation process (tissue sectioning, immunostaining) and cannot monitor the cellular differentiation process in situ, in real-time. Vibrational spectroscopy, as a label-free, non-invasive and non-destructive analytical technique, appears to be a promising candidate to potentially overcome many of these limitations as it can provide detailed biochemical fingerprint information for analysis of cells, tissues, and body fluids. The technique has been widely used in disease diagnosis and increasingly in stem cell technology. In this work, the efforts regarding the use of vibrational spectroscopy to identify mechanisms of stem cell differentiation at a single cell and tissue level are summarised. Both infrared absorption and Raman spectroscopic investigations are explored, and the relative merits, and future perspectives of the techniques are discussed.
Keywords	Keywords: stem cell technology ; vibrational spectroscopy ; Raman spectroscopy ; FTIR absorption spectroscopy ; stem cell differentiation ; spectral markers ; Organic chemistry ; QD241-441
Subject code	571
Language	English
Publishing date	2020-11-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Surface Properties of Saponin—Chitosan Mixtures

Marcel Krzan / Natalia García Rey / Ewelina Jarek / Agnieszka Czakaj / Eva Santini / Francesca Ravera / Libero Liggieri / Piotr Warszynski / Björn Braunschweig

Molecules, Vol 27, Iss 7505, p

2022 Volume 7505

Abstract: The surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that ... ...

Abstract	The surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that saponin-chitosan mixtures present some remarkable properties, such as a strong amphiphilicity of the saponin and high dilational viscoelasticity. We believe this points to the presence of chitosan in the adsorption layer, despite its complete lack of surface activity. We explain this phenomenon by electrostatic interactions between the saponin as an anionic surfactant and chitosan as a polycation, leading to surface-active saponin-chitosan complexes and aggregates. Analysing the SFG intensity of the O-H stretching bands from interfacial water molecules, we found that in the case of pH 3.4 for a mixture consisting of 0.1 g/L saponin and 0.001 g/L chitosan, the adsorption layer was electrically neutral. This conclusion from SFG spectra is corroborated by results from surface tensiometry showing a significant reduction in surface tension and effects on the dilational surface elasticity strictly at saponin/chitosan ratios, where SFG spectra indicate zero net charge at the air–water interface.
Keywords	saponin ; chitosan ; saponin—chitosan interactions ; bio-compatible systems ; biodegradable surfactants ; Organic chemistry ; QD241-441
Subject code	540
Language	English
Publishing date	2022-11-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Effects of Oil Phase on the Inversion of Pickering Emulsions Stabilized by Palmitic Acid Decorated Silica Nanoparticles

Andrés González-González / Natalia Sánchez-Arribas / Eva Santini / José Luis Rodríguez-Villafuerte / Carlo Carbone / Francesca Ravera / Francisco Ortega / Libero Liggieri / Ramón G. Rubio / Eduardo Guzmán

Colloids and Interfaces, Vol 6, Iss 27, p

2022 Volume 27

Abstract: Pickering emulsions stabilized by the interaction of palmitic acid (PA) and silica nanoparticles (SiNPs) at the water/oil interface have been studied using different alkane oil phases. The interaction of palmitic acid and SiNPs has a strong synergistic ... ...

Abstract	Pickering emulsions stabilized by the interaction of palmitic acid (PA) and silica nanoparticles (SiNPs) at the water/oil interface have been studied using different alkane oil phases. The interaction of palmitic acid and SiNPs has a strong synergistic character in relation to the emulsion stabilization, leading to an enhanced emulsion stability in relation to that stabilized only by the fatty acid. This results from the formation of fatty acid-nanoparticle complexes driven by hydrogen bond interactions, which favor particle attachment at the fluid interface, creating a rigid armor that minimizes droplet coalescence. The comparison of emulsions obtained using different alkanes as the oil phase has shown that the hydrophobic mismatch between the length of the alkane chain and the C16 hydrophobic chain of PA determines the nature of the emulsions, with the solubility of the fatty acid in the oil phase being a very important driving force governing the appearance of phase inversion.
Keywords	emulsions ; fatty acid ; hydrophobic mismatch ; phase inversion ; Pickering ; silica nanoparticles ; Chemistry ; QD1-999
Subject code	540
Language	English
Publishing date	2022-04-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The Role of Endogenous Proteins on the Emulsification of Silicone Oils Used in Vitreoretinal Surgery

Irene Nepita / Rodolfo Repetto / Jan O. Pralits / Mario R. Romano / Francesca Ravera / Eva Santini / Libero Liggieri

BioMed Research International, Vol

2020 Volume 2020

Abstract: The present work is aimed at investigating the chemicophysical properties of the interface between silicone oils (SOs) used in vitreoretinal surgery and aqueous solutions, in the presence of surfactant biomolecules. Such molecules are thought to play an ... ...

Abstract	The present work is aimed at investigating the chemicophysical properties of the interface between silicone oils (SOs) used in vitreoretinal surgery and aqueous solutions, in the presence of surfactant biomolecules. Such molecules are thought to play an important role in the formation of SO emulsions in vitrectomised eyes, in which the natural vitreous body has been replaced with a SO. In particular, we have measured the interfacial tension (IT) and the interfacial dilational viscoelasticity (DV) of the interface between SO (Siluron 1000) and serum proteins (albumin and γ-globulins) at various concentrations in a Dulbecco alkaline buffer. The equilibrium IT value is relevant for the onset of emulsification, and the DV influences the stability of an emulsion, once formed. The study is complemented by preliminary emulsification tests. The experimental results show that, when proteins are dissolved in the aqueous solution, the rheological properties of the interface change. The IT decreases significantly for physiological protein concentrations, and the DV modulus achieves high values, even for small protein concentrations. The emulsification tests confirm that, in the presence of proteins, emulsions are stable on the time scale of months. We conclude that the measured values of IT in the presence of serum proteins are compatible with the promotion of droplet formation, which, in addition, are expected to be stable against coalescence. Adsorption of biomolecules at the interface with the SO is, therefore, likely to play an important role in the generation of an emulsion in eyes subjected to vitrectomy. These findings are relevant to identify strategies to avoid or control the formation of emulsions in eyes.
Keywords	Medicine ; R
Subject code	612
Language	English
Publishing date	2020-01-01T00:00:00Z
Publisher	Hindawi Limited
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Adsorption of Sodium Dodecyl Sulfate at Water–Dodecane Interface in Relation to the Oil in Water Emulsion Properties

Llamas, Sara / Davide Orsi / Eva Santini / Fabrizia Salerni / Francesca Ravera / Libero Liggieri / Luigi Cristofolini

Langmuir. 2018 May 02, v. 34, no. 21

2018

Abstract: The control of the behavior of oil in water emulsions requires deeper investigations on the adsorption properties of the emulsion stabilizers at the interfaces, which are fundamental to explain the (de)stabilization mechanisms. In this work, we present ... ...

Abstract	The control of the behavior of oil in water emulsions requires deeper investigations on the adsorption properties of the emulsion stabilizers at the interfaces, which are fundamental to explain the (de)stabilization mechanisms. In this work, we present an extensive study on oil-in-water emulsions stabilized by sodium dodecyl sulfate (SDS) below its critical micellar concentration. Dynamic tensiometry, dilational rheology, and electrical conductivity measurements are used to investigate the adsorption properties at the droplet interface, whereas the aging of the respective emulsions was investigated by monitoring the macroscopic thickness of the emulsion layer, by microimaging and dynamic light scattering (DLS) analysis, to get information on the drop size distribution. In addition, the droplet coalescence is investigated by a microscopy setup. The results of this multitechnique study allow deriving a coherent scenario where the adsorption properties of this ionic surfactant relate to those of the emulsion, such as, for example, the prevention of droplet coalescence and the presence of other mechanisms, such as Ostwald ripening, responsible for the emulsion aging.
Keywords	adsorption ; droplets ; electrical conductivity ; emulsifying properties ; emulsions ; ionic surfactants ; light scattering ; microscopy ; monitoring ; oils ; Ostwald ripening ; rheology ; sodium dodecyl sulfate ; stabilizers
Language	English
Dates of publication	2018-0502
Size	p. 5978-5989.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	2005937-1
ISSN	1520-5827 ; 0743-7463
ISSN (online)	1520-5827
ISSN	0743-7463
DOI	10.1021/acs.langmuir.8b00358
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: A Multistate Adsorption Model for the Adsorption of C 14 EO 4 and C 14 EO 8 at the Solution/Air Interface

Valentin B. Fainerman / Volodymyr I. Kovalchuk / Eugene V. Aksenenko / Francesca Ravera / Libero Liggieri / Giuseppe Loglio / Alexander V. Makievski / Natalia O. Mishchuk / Emanuel Schneck / Reinhard Miller

Colloids and Interfaces, Vol 5, Iss 39, p

2021 Volume 39

Abstract: The dynamic and equilibrium properties of adsorption layers of poly (oxyethylene) alkyl ether (C n EO m ) can be well described by the reorientation model. In its classical version, it assumes two adsorption states; however, there are obviously ... ...

Abstract	The dynamic and equilibrium properties of adsorption layers of poly (oxyethylene) alkyl ether (C n EO m ) can be well described by the reorientation model. In its classical version, it assumes two adsorption states; however, there are obviously surfactants that can adsorb in more than two possible conformations. The experimental data for C 14 EO 4 and C 14 EO 8 (dynamic and equilibrium surface tensions and surface dilational visco-elasticity as measured by bubble profile analysis tensiometry) are used to verify if a reorientation model with more than two possible adsorption states can better describe the complete set data of C n EO m adsorption layers at the water/air interface. The proposed refined theoretical model allows s different states of the adsorbing molecules at the interface. The comparison between the model and experiment demonstrates that, for C 14 EO 4 , the assumption of s = 5 adsorption states provides a much better agreement than for s = 2, while for C 14 EO 8 , a number of s = 10 adsorption states allows an optimum data description.
Keywords	poly (oxyethylene) alkyl ether ; dynamic surface tension ; surface tension isotherm ; dilational surface visco-elasticity ; diffusion controlled adsorption ; reorientation adsorption model ; Chemistry ; QD1-999
Subject code	290
Language	English
Publishing date	2021-07-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Thermodynamics, Kinetics and Dilational Visco‑Elasticity of Adsorbed C n EO m Layers at the Aqueous Solution/Air Interface

Valentin B. Fainerman / Volodymyr I. Kovalchuk / Eugene V. Aksenenko / Francesca Ravera / Libero Liggieri / Giuseppe Loglio / Alexander V. Makievski / Emanuel Schneck / Reinhard Miller

Colloids and Interfaces, Vol 5, Iss 16, p

2021 Volume 16

Abstract: The adsorption behaviour of linear poly(oxyethylene) alkyl ether (C n EO m ) is best described by a reorientation model. Based on a complete set of experimental data, including the adsorption kinetics, the equilibrium surface tension isotherm and the ... ...

Abstract	The adsorption behaviour of linear poly(oxyethylene) alkyl ether (C n EO m ) is best described by a reorientation model. Based on a complete set of experimental data, including the adsorption kinetics, the equilibrium surface tension isotherm and the surface dilational visco-elasticity, the thermodynamic and kinetic adsorption parameters for some C n EO m at the water/air interface were determined. For the study, six C n EO m surfactants were selected ( n = 10, 12 and 14 and m = 4, 5 and 8) and were studied by bubble profile analysis and maximum bubble pressure tensiometry. A refined theoretical model based on a reorientation-adsorption model combined with a diffusion-controlled adsorption kinetics and exchange of matter allowed us to calculate the surface layer composition by adsorbing molecules in different orientations. It turns out that at larger surface coverage, the adsorption rate decreases, i.e., the apparent diffusion coefficients are smaller. This deceleration can be explained by the transition of molecules adsorbed in a state of larger molar surface area into a state with smaller molar surface area.
Keywords	poly(oxyethylene) alkyl ether ; adsorption kinetics ; surface tension isotherm ; dilational surface visco-elasticity ; diffusion-controlled adsorption ; reorientation model ; Chemistry ; QD1-999
Subject code	541
Language	English
Publishing date	2021-03-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Effect of Temperature on the Dynamic Properties of Mixed Surfactant Adsorbed Layers at the Water/Hexane Interface under Low-Gravity Conditions

Volodymyr I. Kovalchuk / Giuseppe Loglio / Alexey G. Bykov / Michele Ferrari / Jürgen Krägel / Libero Liggieri / Reinhard Miller / Olga Yu. Milyaeva / Boris A. Noskov / Francesca Ravera / Eva Santini / Emanuel Schneck

Colloids and Interfaces, Vol 4, Iss 27, p

2020 Volume 27

Abstract: An increase in temperature typically leads to a decrease in the interfacial tension of a water/oil interface. The addition of surfactants to the system can complicate the situation significantly, i.e., the interfacial tension can increase or decrease ... ...

Abstract	An increase in temperature typically leads to a decrease in the interfacial tension of a water/oil interface. The addition of surfactants to the system can complicate the situation significantly, i.e., the interfacial tension can increase or decrease with an increasing temperature. For most concentrations of the two studied surfactants, the cationic tetradecyl trimethyl ammonium bromide (TTAB) and the nonionic tridecyl dimethyl phosphine oxide (C 13 DMPO), the measured interfacial tension of the aqueous mixed surfactant solutions against hexane increases when the temperature decreases between 30 °C and 20 °C. However, with a further temperature decrease between 20 °C and 15 °C, the reverse effect has also been observed at some concentrations, i.e., a decrease of interfacial tension. Additionally, the corresponding dilational interfacial visco-elasticity shows some discrepant temperature effects, depending on the bulk concentration and oscillation frequency. The experiments have been performed with a capillary pressure tensiometer under the conditions of micro-gravity. The reason for the positive and negative interfacial tension and visco-elasticity gradients, respectively, within certain ranges of the temperature, concentration and mixing ratios, are discussed on the basis of all available parameters, such as the solubility and partitioning of the surfactants in the two liquid phases and the oscillation frequency.
Keywords	interfacial dilational viscoelasticity ; mixed surfactant adsorption layer ; water/hexane interface ; drop oscillations ; capillary pressure tensiometry ; effect of temperature ; Chemistry ; QD1-999
Subject code	541
Language	English
Publishing date	2020-07-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Amphiphobic coatings for antifouling in marine environment

Cirisano, Francesca / Alessandro Benedetti / Eva Santini / Francesca Ravera / Libero Liggieri / Michele Ferrari

Colloids and surfaces. 2016 Sept. 20, v. 505

2016

Abstract: Highly hydro and oleophobic materials applied to needs of the marine environment represent a relatively young field achieving growing interest as innovative solution, where technological and ecological aspects allow to be merged, taking into account the ... ...

Abstract	Highly hydro and oleophobic materials applied to needs of the marine environment represent a relatively young field achieving growing interest as innovative solution, where technological and ecological aspects allow to be merged, taking into account the limitations imposed by international laws in terms of environmental protection.In this work a superhydrophobic (SH) coating for seawater applications has been characterized and tested in both laboratory and field conditions, since investigations in real seawater are crucial to evaluate the behaviour of SH surfaces because of a complexity not reproducible in laboratory. Taking into account the real conditions where the surface can operate oleophobicity can be investigated in presence of organic and inorganic pollution. The amphiphobic surface has been also studied to simulate those applications where the surface undergoes to thermal stress like pipelines and desalination plants affected by biofouling.The preliminary wearing test shows the effective resistance to a continuous low velocity impact of micrometric particles of the coating investigated here.Finally, time durability in field tests has been studied as a function of immersion angle in real seawater environment to investigate the role of the coating on early stages of biofilm growth.
Keywords	antifouling agents ; biofilm ; coatings ; desalination ; durability ; hydrophobicity ; marine environment ; pipelines ; pollution ; seawater ; thermal stress
Language	English
Dates of publication	2016-0920
Size	p. 158-164.
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	1500517-3
ISSN	0927-7757
ISSN	0927-7757
DOI	10.1016/j.colsurfa.2016.03.045
Database	NAL-Catalogue (AGRICOLA)

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Article: Effect of silica nanoparticles on the interfacial properties of a canonical lipid mixture

GuzmÃ¡n, Eduardo / Eva Santini / Francesca Ravera / Libero Liggieri / Michele Ferrari

Colloids and Surfaces B: Biointerfaces. 2015 Dec. 01, v. 136

2015

Abstract: The incorporation of silica nanoparticles (NPs) from the subphase into Langmuir lipid monolayers formed by three components, 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC), 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and Cholesterol (Chol), ... ...

Abstract	The incorporation of silica nanoparticles (NPs) from the subphase into Langmuir lipid monolayers formed by three components, 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC), 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and Cholesterol (Chol), modifies the thermodynamic and rheological behavior, as well as the structure of the pristine lipid film. Thus, the combination of structural characterization techniques, such as Brewster Angle Microscopy (BAM) and Atomic Force Microscopy (AFM), with interfacial thermodynamic and dilational rheology studies has allowed us to deepen on the physico-chemical bases governing the interaction between lipid molecules and NPs. The penetration of NPs driven by the interaction (electrostatic or hydrogen bonds) with the polar groups of the lipid molecules affects the phase behaviour (surface pressure-area, ÐâA , isotherm) of the monolayer. This can be easily rationalized considering the modification of the packing and cohesion of the molecules at the interface as revealed BAM and AFM images. Furthermore, oscillatory barrier experiments have allowed obtaining information related to the effect of NPs on the monolayer response under dynamic conditions that presents a critical impact on the characterization of biological relevant systems because most of the processes of interest for these systems present a dynamic character.
Keywords	atomic force microscopy ; cholesterol ; cohesion ; colloids ; hydrogen bonding ; nanoparticles ; rheological properties ; rheology ; silica ; thermodynamics
Language	English
Dates of publication	2015-1201
Size	p. 971-980.
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	1500523-9
ISSN	1873-4367 ; 0927-7765
ISSN (online)	1873-4367
ISSN	0927-7765
DOI	10.1016/j.colsurfb.2015.11.001
Database	NAL-Catalogue (AGRICOLA)

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