Formation and thermodynamic stability of (polymer+porphyrin) supramolecular structures in aqueous solutions

Costa, Viviana C. P. da; Hwang, Barrington; Eggen, Spencer E.; Wallace, Megan J.; Annunziata, Onofrio

doi:10.1016/j.jct.2014.02.025

Cited by 7 publications

(5 citation statements)

References 40 publications

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“…71 To minimize effects related to minor differences in the thermodynamic activities of the buffer components, ionic strength and pH, the filtrate obtained from the ultrafiltration procedure was used as the titrand. The dendrimer volume fraction inside the ITC cell after injection k was calculated using 71…”

Section: Isothermal Titration Calorimetrymentioning

confidence: 99%

“…The excess internal energy associated with dendrimer-dendrimer interactions was measured by Isothermal Titration Calorimetry (ITC) using the MicroCal iTC200 System from GE Healthcare Life Sciences. 71 All experiments were performed at 25.0 1C. In these experiments, dendrimer aqueous salt solution were exhaustively dialyzed against an aqueous salt buffer (ACES, pH 7.0, 0.10 M; sodium sulfate, 0.030 M; ionic strength, 0.14 M) and concentrated by ultrafiltration.…”

Section: Isothermal Titration Calorimetrymentioning

confidence: 99%

“…The use of the factors, V AE 0.5 kn, instead of V represents small corrections taking into account sample displacement outside the ITC cell. 71 The mathematical expression shown for V D Q (k) /V in Section 3 is then inserted into eqn (2). Note that superscript ''k'' will be omitted in Section 3 since V D Q/V is a continuum function of the sample composition.…”

Section: Isothermal Titration Calorimetrymentioning

confidence: 99%

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Unusual liquid–liquid phase transition in aqueous mixtures of a well-known dendrimer

Costa

Annunziata

2015

Phys. Chem. Chem. Phys.

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Liquid-liquid phase separation (LLPS) has been extensively investigated for polymer and protein solutions due to its importance in mixture thermodynamics, separation science and self-assembly processes. However, to date, no experimental studies have been reported on LLPS of dendrimer solutions. Here, it is shown that LLPS of aqueous solutions containing a hydroxyl-functionalized poly(amido amine) dendrimer of fourth generation is induced in the presence of sodium sulfate. Both the LLPS temperature and salt-dendrimer partitioning between the two coexisting phases at constant temperature were measured. Interestingly, our experiments show that LLPS switches from being induced by cooling to being induced by heating as the salt concentration increases. The two coexisting phases also show opposite temperature response. Thus, this phase transition exhibits a simultaneous lower and upper critical solution temperature-type behavior. Dynamic light-scattering and dye-binding experiments indicate that no appreciable conformational change occurs as the salt concentration increases. To explain the observed phase behavior, a thermodynamic model based on two parameters was developed. The first parameter, which describes dendrimer-dendrimer interaction energy, was determined by isothermal titration calorimetry. The second parameter describes the salt salting-out strength. By varying the salting-out parameter, it is shown that the model achieves agreement not only with the location of the experimental binodal at 25 °C but also with the slope of this curve around the critical point. The proposed model also predicts that the unusual temperature behavior of this phase transition can be described as the net result of two thermodynamic factors with opposite temperature responses: salt thermodynamic non-ideality and salting-out strength.

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Section: Isothermal Titration Calorimetrymentioning

confidence: 99%

Section: Isothermal Titration Calorimetrymentioning

confidence: 99%

Section: Isothermal Titration Calorimetrymentioning

confidence: 99%

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Unusual liquid–liquid phase transition in aqueous mixtures of a well-known dendrimer

Costa

Annunziata

2015

Phys. Chem. Chem. Phys.

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“…In our case, both dye and polymer PSS backbone are anionic, therefore we can suggest that decay of the J-aggregates is favored by electrostatic repulsive forces; such a driving force acts to disintegrate different molecular assemblies including dimers [37]. At the same time, one can expect attractive interaction of the dye anion and positive PEDOT backbone in the dye-PEDOT:PSS mixture.…”

Section: Behavior Of Complex Solutionsmentioning

confidence: 60%

Interplay of monomers, dimers and J-aggregates of thiamonomethinecyanine dye with PEDOT and PSS in the dye–PEDOT:PSS composite system

2015

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“…Porphyrin-polymer complexes were extensively used in the last decade for both various analytical, industrial and medical applications and also for developments in theoretical chemistry [15].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Porphyrin-Polymeric Materials and their Amazing Applications: A Review

Fagadar‐Cosma

Făgădar-Cosma

Bîrdeanu

2016

J. Res. Updates Polym. Sci.

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Porphyrins are versatile multifunctional biomimetic molecules that are obtained by condensation of pyrrole with the desired aromatic aldehydes. The porphyrin structure can be synthetically modified by either introduction of various peripheral functional groups or metals in its core, allowing creation of various porphyrin derivatives that exhibit amazing optoelectronic properties. This feature makes porphyrins molecules extremely useful especially in hybrid combination with photonic, electronic and magnetic compounds. This review is focused on the more recently obtained porphyrin-polymeric materials and on their various analytical, industrial and medical applications. The study underlines the assembling capacity of these porphyrin-polymer hybrids to form supramolecular tunable architectures by means of the association of more building block units. Porphyrin-polymer nano-and micro-materials play a preeminent role in sensing applications involving chromophores in the formulation of organic solar cells-due to their capacity to generate photo induced charge separation centers-and as new materials with interesting catalytic properties. Besides these technical applications, the photobactericidal activity of these porphyrin-polymer materials was evaluated against Gram positive and Gram negative strains bacteria and they represent an alternative to antibiotics in order to overcome the growing bacterial multiresistance. Polymer functionalization with porphyrin is commonly used to overcome some drawbacks such as self-quenching and photo-toxicity to the skin produced by the bare porphyrins, when used as photosensitizers in the non-invasive Photodynamic therapy of cancer (PDT).

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Formation and thermodynamic stability of (polymer+porphyrin) supramolecular structures in aqueous solutions

Cited by 7 publications

References 40 publications

Unusual liquid–liquid phase transition in aqueous mixtures of a well-known dendrimer

Unusual liquid–liquid phase transition in aqueous mixtures of a well-known dendrimer

Interplay of monomers, dimers and J-aggregates of thiamonomethinecyanine dye with PEDOT and PSS in the dye–PEDOT:PSS composite system

Hybrid Porphyrin-Polymeric Materials and their Amazing Applications: A Review

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