Catechins as Model Bioactive Compounds for Biomedical Applications

Research regarding polyphenols has gained prominence over the years because of their potential as pharmacological nutrients. Most polyphenols are flavanols, commonly known as catechins, which are present in high amounts in green tea. Catechins are promising candidates in the field of biomedicine. The health benefits of catechins, notably their antioxidant effects, are related to their chemical structure and the total number of hydroxyl groups. In addition, catechins possess strong activities against several pathogens, including bacteria, viruses, parasites, and fungi. One major limitation of these compounds is low bioavailability. Catechins are poorly absorbed by intestinal barriers. Some protective mechanisms may be required to maintain or even increase the stability and bioavailability of these molecules within living organisms. Moreover, novel delivery systems, such as scaffolds, fibers, sponges, and capsules, have been proposed. This review focuses on the unique structures and bioactive properties of catechins and their role in inflammatory responses as well as provides a perspective on their use in future human health applications.

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The Potential of Fucose-Containing Sulfated Polysaccharides As Scaffolds for Biomedical Applications

Current Medicinal Chemistry ◽

10.2174/0929867326666181213093718 ◽

2019 ◽

Vol 26 (35) ◽

pp. 6399-6411 ◽

Cited By ~ 2

Author(s):

Cláudia Nunes ◽

Manuel A. Coimbra

Keyword(s):

Tissue Regeneration ◽

Cell Walls ◽

Biomedical Applications ◽

Structural Features ◽

Therapeutic Agents ◽

Sulfated Polysaccharides ◽

Clinical Use ◽

Health Related ◽

Pathogen Inhibition ◽

Health Applications

Marine environments have a high quantity and diversity of sulfated polysaccharides. In coastal regions brown algae are the most abundant biomass producers and their cell walls have fucosecontaining sulfated polysaccharides (FCSP), known as fucans and/or fucoidans. These sulfated compounds have been widely researched for their biomedical properties, namely the immunomodulatory, haemostasis, pathogen inhibition, anti-inflammatory capacity, and antitumoral. These activities are probably due to their ability to mimic the carbohydrate moieties of mammalian glycosaminoglycans. Therefore, the FCSP are interesting compounds for application in health-related subjects, mainly for developing scaffolds for delivery systems or tissue regeneration. FCSP showed potential for these applications also due to their ability to form stable 3D structures with other polymers able to entrap therapeutic agents or cell and growth factors, besides their biocompatibility and biodegradability. However, for the clinical use of these biopolymers well-defined reproducible molecules are required in order to accurately establish relationships between structural features and human health applications.

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Biomedical Uses of Sulfobetaine-Based Zwitterionic Materials

Organic Materials ◽

10.1055/s-0040-1721741 ◽

2020 ◽

Vol 02 (04) ◽

pp. 342-357

Author(s):

Francesco Zaccarian ◽

Matthew B. Baker ◽

Matthew J. Webber

Keyword(s):

Biomedical Applications ◽

Foreign Body Reaction ◽

Inflammatory Responses ◽

Cellular Adhesion ◽

Review Of The Literature ◽

Future Prospects ◽

Protein Fouling ◽

Biomedical Device ◽

The Many ◽

Hydrophilic Coatings

Protein fouling can render a biomedical device dysfunctional, and also serves to nucleate the foreign body reaction to an implanted material. Hydrophilic coatings have emerged as a commonly applied route to combat interface-mediated complications and promote device longevity and limited inflammatory response. While polyethylene glycol has received a majority of the attention in this regard, coatings based on zwitterionic moieties have been more recently explored. Sulfobetaines in particular constitute one such class of zwitterions explored for use in mitigating surface fouling, and have been shown to reduce protein adsorption, limit cellular adhesion, and promote increased functional lifetimes and limited inflammatory responses when applied to implanted materials and devices. Here, we present a focused review of the literature surrounding sulfobetaine, beginning with an understanding of its chemistry and the methods by which it is applied to the surface of a biomedical device in molecular and polymeric forms, and then advancing to the many early demonstrations of function in a variety of biomedical applications. Finally, we provide some insights into the benefits and challenges presented by its use, as well as some outlook on the future prospects for using this material to improve biomedical device practice by addressing interface-mediated complications.

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Modeling of sorption kinetics of U(VI) micro-quantities nanostructured materials with anatase mesoporous structures

Radiochimica Acta ◽

10.1515/ract-2021-1031 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Veniamin Zheleznov ◽

Aleksey Golikov ◽

Tatiana Sokolnitskaya ◽

Sergey Ivannikov

Keyword(s):

Nanostructured Materials ◽

Sorption Kinetics ◽

Uranyl Ion ◽

Competitive Sorption ◽

Hydroxyl Groups ◽

Complex Ions ◽

The Stability ◽

Kinetics Of ◽

Mesoporous Structures ◽

Ionic Forms

Abstract The sorption kinetics of uranyl ions micro-quantities from fluoride solutions by nanostructured materials with anatase mesoporous structures has been studied. Using the model of competitive sorption of ions and positively charged complexes of uranyl ion on deprotonated hydroxyl groups of an anatase, kinetic curves of changes in the ratio of ionic forms of uranium in solution were calculated. Modeling was carried out under the assumption of a two-stage mechanism of uranium complex ions sorption. The modeling considered the influence of the uranyl ion carbonate complexes formation. The shift in equilibrium among ionic forms of uranyl correlates with the stability of the complexes in solution.

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BALLAST WATER POLLUTION RISK ASSESSMENT IN THE BLACK SEA

Mechanical Testing and Diagnosis ◽

10.35219/mtd.2020.4.05 ◽

2021 ◽

Vol 10 (4) ◽

pp. 35-40

Author(s):

Vasile RAŢᾸ ◽

Liliana RUSU

Keyword(s):

Risk Assessment ◽

Black Sea ◽

Marine Environment ◽

Ballast Water ◽

Safety Net ◽

The Black Sea ◽

Natural Food ◽

Economic Activities ◽

Living Organisms ◽

The Stability

Since the emergence of humanity, the marine environment has provided a safety net in many ways, has fostered socio-economic development, creating links between states, between continents. In the same time, it represents a priority source of food for a considerable percentage of the population. The same marine environment also creates solutions to current global problems, as a potential source of sustainable energy for the future. In recent decades, the stability of this ecosystem has been considerably shaken by the various types of pollution resulting from human activities. The Black Sea is not immune to these results from economic activities, such as the transport of goods by water, which creates the context for the migration of living organisms from one geographical region to another. The threat of ecosystems has been intensified by the process of globalization, by changing the natural food chains following the accidental introduction of non- indigenous marine life by discharging ballast water from ship tanks. Risk assessment to limit the effects of this biohazard problem is the first step in a normal regional chain of action..

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Introduction of Surface Loops as a Tool for Encapsulin Functionalization.

10.1101/2021.05.13.444092 ◽

2021 ◽

Author(s):

Sandra Michel-Souzy ◽

Naomi M. Hamelmann ◽

Sara Zarzuela-Pura ◽

Jos M. J. Paulusse ◽

Jeroen J. L. M. Cornelissen

Keyword(s):

Biomedical Applications ◽

Large Scale ◽

Thermotoga Maritima ◽

Scale Production ◽

Structure Property ◽

Protein Subunit ◽

Protein Cages ◽

Notable Increase ◽

The Stability ◽

Surface Loops

Encapsulin based protein cages are nanoparticles with different biomedical applications, such as targeted drug delivery or imaging agents. These particles are biocompatible and can be produced in bacteria, allowing large scale production and protein engineering. In order to use these bacterial nanocages in different applications, it is important to further explore the potential of their surface modification and optimize their production. In this study we design and show new surface modifications of the Thermotoga maritima (Tm) and Brevibacterium linens (Bl) encapsulins. Two new loops on Tm encapsulin with a His-tag insertion after the residue 64 and the residue 127, and the modification of the C-terminal on Bl encapsulin, are reported. The multi-modification of the Tm encapsulin enables up to 240 different functionalities on the cage surface, resulting from 4 potential modifications per protein subunit. We furthermore report an improved protocol giving a better stability and providing a notable increase of the production yield of the cages. Finally, we tested the stability of different encapsulin variants over a year and the results show a difference in stability arising from the tag insertion position. These first insights in the structure-property relationship of encapsulins, with respect to the position of a function loop, allow for further study of the use of these protein nanocages in biomedical applications.

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Active surface centres in vanadium pentoxide/alkali metal sulphate heterogeneous catalysts for 2-propanol decomposition

Canadian Journal of Chemistry ◽

10.1139/v79-392 ◽

1979 ◽

Vol 57 (18) ◽

pp. 2464-2469 ◽

Cited By ~ 6

Author(s):

David Victor Fikis ◽

William John Murphy ◽

Robert Anderson Ross

Keyword(s):

Alkali Metal ◽

Surface Area ◽

Vanadium Pentoxide ◽

Heterogeneous Catalysts ◽

Catalyst Activity ◽

Active Surface ◽

Hydroxyl Groups ◽

Kinetic Measurements ◽

The Stability ◽

The Individual

Infrared spectra of the surfaces of vanadium pentoxide and vanadium pentoxide containing 9.09 mol% caesium and potassium, as sulphates, have been determined after exposure to 2-propanol for various times. Interpretation of the spectra leads to the proposal that the principal source of catalyst activity may be associated with surface hydrogen and hydroxyl groups on V5+ and V4+ sites. The "stability" of the catalysts towards reduction by the alcohol was consistent with the activity series derived from kinetic measurements: V2O5 (pure) < V2O5 (Cs) < V2O5 (K). The degree of sample reduction has also been assessed qualitatively by measurements of the ratio of surface area before to that after reaction and the same catalyst sequence was established. The trend in surface area ratios was similar to that shown by the surface "Tammann" temperatures of vanadium pentoxide and alkali metal sulphates which has been taken to imply that the ease and (or) extent with which the sulphates enter into inter-solid reactions with the oxide in the preparation stage may exert influence on the subsequent reducibility of the individual members of the catalyst series.

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Study on lignin-free lignocellulosic biomass and PSF-PEG membrane compatibility

BioResources ◽

10.15376/biores.16.1.1063-1075 ◽

2020 ◽

Vol 16 (1) ◽

pp. 1063-1075

Author(s):

Abiodun A. Amusa ◽

Abdul L. Ahmad ◽

Jimoh K. Adewole

Keyword(s):

Contact Angle ◽

Fourier Transform ◽

Infrared Spectroscopy ◽

Lignocellulosic Biomass ◽

Biomedical Applications ◽

Composite Membranes ◽

Hydroxyl Groups ◽

Chemical Pretreatment ◽

Physical And Chemical ◽

Porosity Measurements

Lignocellulosic biomass was delignified by combining physical and chemical pretreatment techniques. Then, a polysulfone-polyethylene glycol blend, which was compatible with the lignin-free biomass (0 wt% to 3.0 wt%), was used to fabricate composite membranes. The presence of hydroxyl groups after the pretreatment was evaluated via Fourier transform infrared spectroscopy. The rheology of the polymer solutions was assessed via the viscometric method. Also, the hydrophobicity of the fabricated membranes was determined using contact angle and porosity measurements. The fabricated membranes with near superhydrophobic properties (a contact angle of approximately 140°) based on this study revealed that contactor systems and biomedical applications would benefit from this modification.

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Stability of Engineered Micro or Nanobubbles for Biomedical Applications

Pharmaceutics ◽

10.3390/pharmaceutics12111089 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1089

Author(s):

Beomjin Park ◽

Semi Yoon ◽

Yonghyun Choi ◽

Jaehee Jang ◽

Soomin Park ◽

...

Keyword(s):

Drug Delivery ◽

Biomedical Applications ◽

Ultrasonic Field ◽

Nanometer Scale ◽

Factors Affecting ◽

The Core ◽

Bubble Structure ◽

The Stability ◽

The Relationship

A micro/nanobubble (MNB) refers to a bubble structure sized in a micrometer or nanometer scale, in which the core is separated from the external environment and is normally made of gas. Recently, it has been confirmed that MNBs can be widely used in angiography, drug delivery, and treatment. Thus, MNBs are attracting attention as they are capable of constructing a new contrast agent or drug delivery system. Additionally, in order to effectively use an MNB, the method of securing its stability is also being studied. This review highlights the factors affecting the stability of an MNB and the stability of the MNB within the ultrasonic field. It also discusses the relationship between the stability of the bubble and its applicability in vivo.

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Marine Polysaccharides in Pharmaceutical Applications: Fucoidan and Chitosan as Key Players in the Drug Delivery Match Field

Marine Drugs ◽

10.3390/md17120654 ◽

2019 ◽

Vol 17 (12) ◽

pp. 654 ◽

Cited By ~ 13

Author(s):

Ana Isabel Barbosa ◽

Ana Joyce Coutinho ◽

Sofia A. Costa Lima ◽

Salette Reis

Keyword(s):

Drug Delivery ◽

Tissue Engineering ◽

Biomedical Applications ◽

Chemical Structure ◽

Final Section ◽

Biological Properties ◽

Production Methods ◽

Bioactive Properties ◽

Wide Range ◽

Per Se

The use of marine-origin polysaccharides has increased in recent research because they are abundant, cheap, biocompatible, and biodegradable. These features motivate their application in nanotechnology as drug delivery systems; in tissue engineering, cancer therapy, or wound dressing; in biosensors; and even water treatment. Given the physicochemical and bioactive properties of fucoidan and chitosan, a wide range of nanostructures has been developed with these polysaccharides per se and in combination. This review provides an outline of these marine polysaccharides, including their sources, chemical structure, biological properties, and nanomedicine applications; their combination as nanoparticles with descriptions of the most commonly used production methods; and their physicochemical and biological properties applied to the design of nanoparticles to deliver several classes of compounds. A final section gives a brief overview of some biomedical applications of fucoidan and chitosan for tissue engineering and wound healing.

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Impaired RIPK1 ubiquitination sensitizes mice to TNF toxicity and inflammatory cell death

Cell Death and Differentiation ◽

10.1038/s41418-020-00629-3 ◽

2020 ◽

Author(s):

Matthias Kist ◽

László G. Kőműves ◽

Tatiana Goncharov ◽

Debra L. Dugger ◽

Charles Yu ◽

...

Keyword(s):

Cell Death ◽

Inflammatory Responses ◽

Mapk Signaling ◽

Embryonic Lethality ◽

Mapk Activation ◽

Interacting Protein ◽

Signaling Complex ◽

Ubiquitination Site ◽

Lysine Residues ◽

The Stability

Abstract Receptor-interacting protein 1 (RIP1; RIPK1) is a key regulator of multiple signaling pathways that mediate inflammatory responses and cell death. TNF-TNFR1 triggered signaling complex formation, subsequent NF-κB and MAPK activation and induction of cell death involve RIPK1 ubiquitination at several lysine residues including Lys376 and Lys115. Here we show that mutating the ubiquitination site K376 of RIPK1 (K376R) in mice activates cell death resulting in embryonic lethality. In contrast to Ripk1K376R/K376R mice, Ripk1K115R/K115R mice reached adulthood and showed slightly higher responsiveness to TNF-induced death. Cell death observed in Ripk1K376R/K376R embryos relied on RIPK1 kinase activity as administration of RIPK1 inhibitor GNE684 to pregnant heterozygous mice effectively blocked cell death and prolonged survival. Embryonic lethality of Ripk1K376R/K376R mice was prevented by the loss of TNFR1, or by simultaneous deletion of caspase-8 and RIPK3. Interestingly, elimination of the wild-type allele from adult Ripk1K376R/cko mice was tolerated. However, adult Ripk1K376R/cko mice were exquisitely sensitive to TNF-induced hypothermia and associated lethality. Absence of the K376 ubiquitination site diminished K11-linked, K63-linked, and linear ubiquitination of RIPK1, and promoted the assembly of death-inducing cellular complexes, suggesting that multiple ubiquitin linkages contribute to the stability of the RIPK1 signaling complex that stimulates NF-κB and MAPK activation. In contrast, mutating K115 did not affect RIPK1 ubiquitination or TNF stimulated NF-κB and MAPK signaling. Overall, our data indicate that selective impairment of RIPK1 ubiquitination can lower the threshold for RIPK1 activation by TNF resulting in cell death and embryonic lethality.

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