Interfacial water and its potential role in the function of sericin against biofouling

Pedregal-Cortés, Ricardo; Toríz, Guillermo; Delgado, Ezequiel; Pollack, Gerald H.

doi:10.1080/08927014.2019.1653863

Cited by 12 publications

(10 citation statements)

References 47 publications

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“…Furthermore, due to the physical nature of the exclusion mechanism, this action of propolis should be very generic, rather that particle (or pathogen) specific. Indeed, EZ water has been recognized to exclude a variety of solutes starting from simple salt ions to microparticles and microorganisms [ [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] ]. Hence, colloidal particles in sizes ranging from viruses to bacteria should be effectively rejected.…”

Section: Discussionmentioning

confidence: 99%

“…Many experiments have demonstrated that next to various surfaces possessing hydrophilic functional groups, there is a layer of water that excludes solutes ranging from ions, organic molecules and proteins to polystyrene microspheres and bacterial cells [ [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] ]. Due to those properties, this layer of water has been given a generic name of “exclusion zone” (EZ).…”

Section: Introductionmentioning

confidence: 99%

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Propolis-induced exclusion of colloids: Possible new mechanism of biological action

Kowacz

Pollack

2020

Colloid and Interface Science Communications

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Propolis is a natural product originating from life activity of honeybees. It exhibits wide range of biological properties applicable in medicine, the food industry, and cosmetics. Chemically, propolis is a complex and variable mixture with more than 300 identified biologically active components. Propolis's many health-promoting effects are attributed to different biochemical mechanisms, mediated by often-concerted actions of some of its many constituents. Propolis is considered safe and biocompatible. Yet due to its intrinsic complexity, standardization of propolis preparations for medical use as well as prediction of e.g. pathogen-specific interactions becomes a non-trivial task. In this work we demonstrate a new physical mechanism of propolis action, largely independent of specific nuances of propolis chemistry, which may underlie some of its biological actions. We show that propolis-bearing surfaces generate an extensive exclusion zone (EZ) water layer. EZ is an interfacial region of water capable of excluding solutes ranging from ions to microorganisms. Propolis-generated EZ may constitute an effective barrier, physically disabling the approach of various pathogens to the propolis-functionalized surfaces. We suggest possible implications of this new mechanism for propolis-based prevention of respiratory infections.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Propolis-induced exclusion of colloids: Possible new mechanism of biological action

Kowacz

Pollack

2020

Colloid and Interface Science Communications

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“…[51,52] It has indeed been suggested that due to its hydrophilic character, SS can extract water molecules from spherical micellar (coiled) SF aggregates, which favors self-assembly by promoting inter-and intramolecular hydrogen bonds, and induces a transition into nanofibrils (𝛽-sheets) (Figure 2E). [51] Moreover, since SS is an antifouling polymer, it exhibits a socalled solute exclusion zone in water [53,54] resulting in a decreased solution pH. [55][56][57][58][59] This effectively neutralizes (protonates) the negatively charged amino acids of SF (Asp and Glu) and facilitates inter-and intramolecular hydrogen bonds, [60] likewise inducing the transition from random coils to 𝛽-sheets.…”

Section: Structure and Physicochemical Propertiesmentioning

confidence: 99%

“…[4] The SS component also improves the antimicrobial properties of SS-SF composites by increasing the acidity of the cell medium, which is especially harmful to neutrophilic bacteria (Figure 1). [53,61] It therefore appears from the various studies cited that the combination of SF and SS leads to synergy in the biological and mechanical properties of both materials, such that biomaterials based on these proteins should be attractive for tissue engineering applications.…”

Section: Structure and Physicochemical Propertiesmentioning

confidence: 99%

Immune Response to Silk Sericin–Fibroin Composites: Potential Immunogenic Elements and Alternatives for Immunomodulation

Boni

Bakadia

Osi

et al. 2021

Macromolecular Bioscience

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The unique properties of silk proteins (SPs), particularly silk sericin (SS) and silk fibroin (SF), have attracted attention in the design of scaffolds for tissue engineering over the past decades. Since SF has good mechanical properties, while SS displays bioactivity, scaffolds combining both proteins should exhibit complementary properties enhancing the potential of these materials. Unfortunately, SS-SF composites can generate chronic immune responses and their immunogenic element is not completely clear. The potential of SS-SF composites in tissue engineering, elements which may contribute to their immunogenicity, and alternatives for their preparation and design, to modulate the immune response and take advantage of their useful properties, are discussed in this review. It is known that SS can enhance 𝜷-sheet formation in SF, which may act as hydrophobic regions with a strong affinity for adsorption proteins inducing the chronic recruitment of inflammatory cells. Therefore, tailoring the exposure of hydrophobic regions at the scaffold surface should represent a viable strategy to modulate the immune response. This can be achieved by coating SS-SF composites with SS or other hydrophilic polymers, to take advantage of their antibiofouling properties. Research is still needed to realize the full potential of these composites for tissue engineering.

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“…In any given experimental scenario, some or all of those mechanism may be present. EZ phenomena may have important engineering applications in water filtration, reducing biofouling [ 16 ], and microfluidics [ 6 ]. EZ phenomena also have obvious importance to understanding biological systems and resolving outstanding questions about “biological water” [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Exclusion Zone Phenomena in Water—A Critical Review of Experimental Findings and Theories

Elton

Spencer

Riches³

et al. 2020

IJMS

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The existence of the exclusion zone (EZ), a layer of water in which plastic microspheres are repelled from hydrophilic surfaces, has now been independently demonstrated by several groups. A better understanding of the mechanisms which generate EZs would help with understanding the possible importance of EZs in biology and in engineering applications such as filtration and microfluidics. Here we review the experimental evidence for EZ phenomena in water and the major theories that have been proposed. We review experimental results from birefringence, neutron radiography, nuclear magnetic resonance, and other studies. Pollack theorizes that water in the EZ exists has a different structure than bulk water, and that this accounts for the EZ. We present several alternative explanations for EZs and argue that Schurr’s theory based on diffusiophoresis presents a compelling alternative explanation for the core EZ phenomenon. Among other things, Schurr’s theory makes predictions about the growth of the EZ with time which have been confirmed by Florea et al. and others. We also touch on several possible confounding factors that make experimentation on EZs difficult, such as charged surface groups, dissolved solutes, and adsorbed nanobubbles.

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Interfacial water and its potential role in the function of sericin against biofouling

Cited by 12 publications

References 47 publications

Propolis-induced exclusion of colloids: Possible new mechanism of biological action

Propolis-induced exclusion of colloids: Possible new mechanism of biological action

Immune Response to Silk Sericin–Fibroin Composites: Potential Immunogenic Elements and Alternatives for Immunomodulation

Exclusion Zone Phenomena in Water—A Critical Review of Experimental Findings and Theories

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