UV–Vis Reflection–Absorption Spectroscopy at air–liquid interfaces

Rubia-Payá, Carlos; Miguel, Gustavo de; Martín‐Romero, María T.; Giner‐Casares, Juan J.; Camacho, Luis

doi:10.1016/j.cis.2015.08.012

Cited by 19 publications

(15 citation statements)

References 90 publications

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“…[24] The amount of QD_F present at the phospholipid interface could be quantitatively monitored by in situ UV-vis reflection spectroscopy at the air/water interface. [25] The UV-vis band at the air/water interface confirmed the aggregation of the QD_F at the DPPC monolayer when compared to the UV-vis absorption spectrum recorded for a bulk solution of QD_F, see Fig. 4A.…”

Section: Resultssupporting

confidence: 55%

Fluorinated CdSe/ZnS quantum dots: Interactions with cell membrane

Argudo

Martín‐Romero

Camacho

et al. 2019

Colloids and Surfaces B: Biointerfaces

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Section: Resultssupporting

confidence: 55%

Fluorinated CdSe/ZnS quantum dots: Interactions with cell membrane

Argudo

Martín‐Romero

Camacho

et al. 2019

Colloids and Surfaces B: Biointerfaces

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“…The molecular arrangements for both configurations obtained in the simulations were quantitatively analyzed by applying the extended dipole model to the data obtained by UV–vis reflection experiments. This model establishes a quantitative relation between the relative geometry of the transition dipoles and the shift of the UV–vis reflection bands when aggregation occurs . The position of the UV–vis band of the OPESH supramolecular aggregate (λ N ) with respect to isolated OPESH (λ mon ) can be calculated using where h and c are the Planck’s constant and speed of light in a vacuum, respectively, J 1 i is the interaction energy between the dipoles corresponding to the reference molecule and each i molecule of the lineal aggregate, and N is the aggregation number, N = 2, 3, .... As shown in Figure c,d, the transition dipoles of the OPE groups are placed parallel to each other.…”

Section: Resultsmentioning

confidence: 99%

“…This model establishes a quantitative relation between the relative geometry of the transition dipoles and the shift of the UV−vis reflection bands when aggregation occurs. 59 The position of the UV−vis band of the OPESH supramolecular aggregate (λ N ) with respect to isolated OPESH (λ mon ) can be calculated using…”

Section: ■ Introductionmentioning

confidence: 99%

Mechanosensitive Gold Colloidal Membranes Mediated by Supramolecular Interfacial Self-Assembly

et al. 2017

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The ability to respond toward mechanical stimuli is a fundamental property of biological organisms at both the macroscopic and cellular levels, yet it has been considerably less observed in artificial supramolecular and colloidal homologues. An archetypal example in this regard is cellular mechanosensation, a process by which mechanical forces applied on the cell membrane are converted into biochemical or electrical signals through nanometer-scale changes in molecular conformations. In this article, we report an artificial gold nanoparticle (Au NP)-discrete π-conjugated molecule hybrid system that mimics the mechanical behavior of biological membranes and is able to self-assemble into colloidal gold nanoclusters or membranes in a controlled and reversible fashion by changing the concentration or the mechanical force (pressure) applied. This has been achieved by rational design of a small π-conjugated thiolated molecule that controls, to a great extent, the hierarchy levels involved in Au NP clustering by enabling reversible, cooperative non-covalent (π-π, solvophobic, and hydrogen bonding) interactions. In addition, the Au NP membranes have the ability to entrap and release aromatic guest molecules reversibly (K = 5.0 × 10 M) for several cycles when subjected to compression-expansion experiments, in close analogy to the behavior of cellular mechanosensitive channels. Not only does our hybrid system represent the first example of a reversible colloidal membrane, but it also can be controlled by a dynamic mechanical stimulus using a new supramolecular surface-pressure-controlled strategy. This approach holds great potential for the development of multiple colloidal assemblies within different research fields.

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“…To gain further insight into the surface concentration of the Fmoc-dipeptide derivatives at the air/water interface, in situ UV-vis reflection spectroscopy was applied. 52 The UV-vis reflection signal neglects any contribution from the bulk solution, instead arising exclusively from the enhancement of reflection of the incoming radiation by absorbance of molecules located at the air/water interface according to the equation ( 1):…”

Section: Resultsmentioning

confidence: 99%

Optimization of Amino Acid Sequence of Fmoc-Dipeptides for Interaction with Lipid Membranes

et al. 2019

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Fmoc-dipeptides appear as a highly relevant building block in smart hydrogels and nanovehicles for biological applications. The interactions of the Fmoc-dipeptides with the cell membrane determine the efficiency of the nanomaterials based on the Fmoc-dipeptides, as the internalization of nanovehicles for drug delivery. Here we aim at the understanding of the interplay of the interactions between the Fmoc-dipeptides and a phospholipid surface as a function of the aminoacid sequence. The DMPA (1,2-dimyristoyl-sn-glycero-3-phosphate) phospholipid in Langmuir monolayers was used as a model cell surface. A set of seven derivatives of Fmocdipeptides with a broad range of hydrophobicity were included. Mixed monolayers composed by DMPA:Fmoc-dipeptide in equimolar ratio were built and characterized in situ at the air/water interface. Surface pressure-molecular area isotherms (A), Brewster Angle Microscopy (BAM) and UV-vis reflection spectroscopy (ΔR) were combined to provide a holistic picture on the interactions of the Fmoc-dipeptide with the phospholipid molecules. An increase in the hydrophobicity led to an enhanced interaction of the Fmoc-dipeptide and DMPA molecules. The compression of the mixed monolayer could displace a significant fraction of the Fmoc-dipeptide from the monolayer. A high hydrophobicity promoted self-assembly of the Fmoc-dipeptides over interaction with the phospholipid surface. The interplay of these two phenomena was analyzed as a function of the aminoacid sequence of the Fmoc-dipeptides. The toxicity effect of Fmoc-FF could be observed and detailed at the molecular level. This study suggests that the adjustment of the hydrophobicity of the Fmoc-dipeptides within a defined range might optimize their efficiency for the interaction with the lipid membranes. A semiquantitative guide for the chemical design of Fmoc-dipeptides for biological applications is proposed herein.

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UV–Vis Reflection–Absorption Spectroscopy at air–liquid interfaces

Cited by 19 publications

References 90 publications

Fluorinated CdSe/ZnS quantum dots: Interactions with cell membrane

Fluorinated CdSe/ZnS quantum dots: Interactions with cell membrane

Mechanosensitive Gold Colloidal Membranes Mediated by Supramolecular Interfacial Self-Assembly

Optimization of Amino Acid Sequence of Fmoc-Dipeptides for Interaction with Lipid Membranes

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