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Special Issue "Marine Biomaterials"

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A special issue of Marine Drugs (ISSN 1660-3397).

Deadline for manuscript submissions: closed (31 May 2014)

Special Issue Editor

Guest Editor
Prof. Dr. Hermann Ehrlich

Institute of Experimental Physics, TU Bergakademie Freiberg, Germany
Website | E-Mail
Phone: +00493731 392867
Fax: +0049 3731 394314
Interests: marine biomaterials; biominerals; biocomposites and biomimetics

Special Issue Information

Dear Colleagues,

The biological, chemical and materials diversity of the marine environment is immeasurable and therefore is an extraordinary resource for the discovery of new bioactive substances, drugs, toxins, pigments, enzymes; as well as biopolymers, bioadhesives, bioelastomers and hierarchically structured biocomposites. Recent technological and methodological advances in structure elucidation, genomics, proteomics, organic synthesis, bioinspired materials chemistry, biological assays and biomimetics have resulted in the isolation and clinical evaluation of various novel pharmacological preparations and biomaterials. These compounds range in structural class from simple linear peptides to complex biopolymers. There are no doubts that diversity of biological materials of marine origin is almost equivalent to the marine biodiversity. According to generalized classification of biological materials of marine origin, we pick out:

  • Biomineralized Structures and Biocomposites (skeletal formations, macro- and microscleres, spicules, spines, bristles, cell walls, cyst walls, loricae etc.)
  • Non-mineralized Structures (bioelastomers like abductin, resilin, gorgonin, spongin; antipathin, bioadhesives like byssus and related DOPA-based polymers; biocements and glues)
  • Macromolecular Biopolymers (marine polysaccharides of algal origin; chitin, collagens)
  • Self-made Biological Materials (tubular structures of marine invertebrates like some protists, foraminifera or worms which are made due to co-agglutination of external mineral debris, sand grains or other particles)
Dr. rer. nat. Hermann Ehrlich
Guest Editor

Submission

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Marine Drugs is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs).

Keywords

  • biominerals
  • biocomposites
  • biomimetics
  • biomaterial
  • biosilica
  • bioelastomers
  • calcification
  • chitin
  • collagen
  • corals
  • marine invertebrates
  • spicule

Published Papers (18 papers)

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Research

Jump to: Review

Open AccessArticle Preparation of Photocrosslinked Fish Elastin Polypeptide/Microfibrillated Cellulose Composite Gels with Elastic Properties for Biomaterial Applications
Mar. Drugs 2015, 13(1), 338-353; doi:10.3390/md13010338
Received: 14 November 2014 / Accepted: 26 December 2014 / Published: 9 January 2015
Cited by 4 | PDF Full-text (1418 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N
[...] Read more.
Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N′-dicyclohexylcarbodiimide (DCC), a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI) to yield a photocrosslinkable fish elastin polypeptide. The product was dissolved in DMSO and irradiated with UV light in the presence of a radical photoinitiator. We obtained hydrogels successfully by substitution of DMSO with water. The composite gel with MFC was prepared by UV irradiation of the photocrosslinkable elastin polypeptide mixed with dispersed MFC in DMSO, followed by substitution of DMSO with water. The tensile test of the composite gels revealed that the addition of MFC improved the tensile properties, and the shape of the stress–strain curve of the composite gel became more similar to the typical shape of an elastic material with an increase of MFC content. The rheology measurement showed that the elastic modulus of the composite gel increased with an increase of MFC content. The cell proliferation test on the composite gel showed no toxicity. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessArticle Customizing Properties of β-Chitin in Squid Pen (Gladius) by Chemical Treatments
Mar. Drugs 2014, 12(12), 5979-5992; doi:10.3390/md12125979
Received: 18 September 2014 / Revised: 3 December 2014 / Accepted: 4 December 2014 / Published: 15 December 2014
Cited by 3 | PDF Full-text (916 KB) | HTML Full-text | XML Full-text
Abstract
The squid pen (gladius) from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability
[...] Read more.
The squid pen (gladius) from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessArticle Production, Characterization and Biocompatibility of Marine Collagen Matrices from an Alternative and Sustainable Source: The Sea Urchin Paracentrotus lividus
Mar. Drugs 2014, 12(9), 4912-4933; doi:10.3390/md12094912
Received: 7 July 2014 / Revised: 26 August 2014 / Accepted: 5 September 2014 / Published: 24 September 2014
Cited by 5 | PDF Full-text (1006 KB) | HTML Full-text | XML Full-text
Abstract
Collagen has become a key-molecule in cell culture studies and in the tissue engineering field. Industrially, the principal sources of collagen are calf skin and bones which, however, could be associated to risks of serious disease transmission. In fact, collagen derived from alternative
[...] Read more.
Collagen has become a key-molecule in cell culture studies and in the tissue engineering field. Industrially, the principal sources of collagen are calf skin and bones which, however, could be associated to risks of serious disease transmission. In fact, collagen derived from alternative and riskless sources is required, and marine organisms are among the safest and recently exploited ones. Sea urchins possess a circular area of soft tissue surrounding the mouth, the peristomial membrane (PM), mainly composed by mammalian-like collagen. The PM of the edible sea urchin Paracentrotus lividus therefore represents a potential unexploited collagen source, easily obtainable as a food industry waste product. Our results demonstrate that it is possible to extract native collagen fibrils from the PM and produce suitable substrates for in vitro system. The obtained matrices appear as a homogeneous fibrillar network (mean fibril diameter 30–400 nm and mesh < 2 μm) and display remarkable mechanical properties in term of stiffness (146 ± 48 MPa) and viscosity (60.98 ± 52.07 GPa·s). In vitro tests with horse pbMSC show a good biocompatibility in terms of overall cell growth. The obtained results indicate that the sea urchin P. lividus can be a valuable low-cost collagen source for mechanically resistant biomedical devices. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessArticle Localization and Characterization of Ferritin in Demospongiae: A Possible Role on Spiculogenesis
Mar. Drugs 2014, 12(8), 4659-4676; doi:10.3390/md12084659
Received: 20 May 2014 / Revised: 28 July 2014 / Accepted: 11 August 2014 / Published: 22 August 2014
Cited by 2 | PDF Full-text (1282 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Iron, as inorganic ion or as oxide, is widely used by biological systems in a myriad of biological functions (e.g., enzymatic, gene activation and/or regulation). In particular, marine organisms containing silica structures—diatoms and sponges—grow preferentially in the presence of iron. Using primary sponge
[...] Read more.
Iron, as inorganic ion or as oxide, is widely used by biological systems in a myriad of biological functions (e.g., enzymatic, gene activation and/or regulation). In particular, marine organisms containing silica structures—diatoms and sponges—grow preferentially in the presence of iron. Using primary sponge cell culture from S. domuncula–primmorphs—as an in vitro model to study the Demospongiae spiculogenesis, we found the presence of agglomerates 50 nm in diameter exclusively inside sponge specialized cells called sclerocytes. A clear phase/material separation is observed between the agglomerates and the initial stages of intracellular spicule formation. STEM-HRTEM-EDX analysis of the agglomerates (30–100 nm) showed that they are composed of pseudohexagonal nanoparticles between 5 and 15 nm in size, displaying lattice parameters corresponding to hematite (Fe2O3) and mixed iron oxide phases typically attributed to ferritin. Further analysis, using western blotting, inductively coupled plasma mass spectrometry (ICP-MS), sequence alignment analysis, immunostaining and magnetic resonance imaging (MRI), of mature spicule filaments confirm the presence of ferritin within these organic structures. We suggest that S. domuncula can be classified as a dual biomineralizating organism, i.e., within the same cellular structure two distinct biomineralizing processes can occur as a result of the same cellular/metabolic function, spiculogenesis. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessArticle Preparation and Characterization of Antioxidant Nanoparticles Composed of Chitosan and Fucoidan for Antibiotics Delivery
Mar. Drugs 2014, 12(8), 4379-4398; doi:10.3390/md12084379
Received: 6 May 2014 / Revised: 16 July 2014 / Accepted: 16 July 2014 / Published: 31 July 2014
Cited by 13 | PDF Full-text (2659 KB) | HTML Full-text | XML Full-text
Abstract
In this study, we developed novel chitosan/fucoidan nanoparticles (CS/F NPs) using a simple polyelectrolyte self-assembly method and evaluated their potential to be antioxidant carriers. As the CS/F weight ratio was 5/1, the CS/F NPs were spherical and exhibited diameters of approximately 230–250 nm,
[...] Read more.
In this study, we developed novel chitosan/fucoidan nanoparticles (CS/F NPs) using a simple polyelectrolyte self-assembly method and evaluated their potential to be antioxidant carriers. As the CS/F weight ratio was 5/1, the CS/F NPs were spherical and exhibited diameters of approximately 230–250 nm, as demonstrated by TEM. These CS/F NPs maintained compactness and stability for 25 day in phosphate-buffered saline (pH 6.0–7.4). The CS/F NPs exhibited highly potent antioxidant effects by scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), reducing the concentration of intracellular reactive oxygen species (ROS) and superoxide anion (O2) in stimulated macrophages. The DPPH scavenging effect of CS/F NPs primarily derives from fucoidan. Furthermore, these CS/F NPs activated no host immune cells into inflammation-mediated cytotoxic conditions induced by IL-6 production and NO generation. The MTT cell viability assay revealed an absence of toxicity in A549 cells after exposure to the formulations containing 0.375 mg NPs/mL to 3 mg NPs/mL. Gentamicin (GM), an antibiotic, was used as a model drug for an in vitro releasing test. The CS/F NPs controlled the release of GM for up to 72 h, with 99% of release. The antioxidant CS/F NPs prepared in this study could thus be effective in delivering antibiotics to the lungs, particularly for airway inflammatory diseases. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessArticle Modification of Chitin with Kraft Lignin and Development of New Biosorbents for Removal of Cadmium(II) and Nickel(II) Ions
Mar. Drugs 2014, 12(4), 2245-2268; doi:10.3390/md12042245
Received: 4 February 2014 / Revised: 6 March 2014 / Accepted: 12 March 2014 / Published: 10 April 2014
Cited by 15 | PDF Full-text (1715 KB) | HTML Full-text | XML Full-text
Abstract
Novel, functional materials based on chitin of marine origin and lignin were prepared. The synthesized materials were subjected to physicochemical, dispersive-morphological and electrokinetic analysis. The results confirm the effectiveness of the proposed method of synthesis of functional chitin/lignin materials. Mechanism of chitin modification
[...] Read more.
Novel, functional materials based on chitin of marine origin and lignin were prepared. The synthesized materials were subjected to physicochemical, dispersive-morphological and electrokinetic analysis. The results confirm the effectiveness of the proposed method of synthesis of functional chitin/lignin materials. Mechanism of chitin modification by lignin is based on formation of hydrogen bonds between chitin and lignin. Additionally, the chitin/lignin materials were studied from the perspective of waste water treatment. The synthetic method presented in this work shows an attractive and facile route for producing low-cost chitin/lignin biosorbents with high efficiency of nickel and cadmium adsorption (88.0% and 98.4%, respectively). The discovery of this facile method of synthesis of functional chitin/lignin materials will also have a significant impact on the problematic issue of the utilization of chitinous waste from the seafood industry, as well as lignin by-products from the pulp and paper industry. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessArticle Effects of Chitin and Sepia Ink Hybrid Hemostatic Sponge on the Blood Parameters of Mice
Mar. Drugs 2014, 12(4), 2269-2281; doi:10.3390/md12042269
Received: 25 January 2014 / Revised: 18 March 2014 / Accepted: 25 March 2014 / Published: 10 April 2014
Cited by 4 | PDF Full-text (623 KB) | HTML Full-text | XML Full-text
Abstract
Chitin and sepia ink hybrid hemostatic sponge (CTSH sponge), a new biomedical material, was extensively studied for its beneficial biological properties of hemostasis and stimulation of healing. However, studies examining the safety of CTSH sponge in the blood system are lacking. This experiment
[...] Read more.
Chitin and sepia ink hybrid hemostatic sponge (CTSH sponge), a new biomedical material, was extensively studied for its beneficial biological properties of hemostasis and stimulation of healing. However, studies examining the safety of CTSH sponge in the blood system are lacking. This experiment aimed to examine whether CTSH sponge has negative effect on blood systems of mice, which were treated with a dosage of CTSH sponge (135 mg/kg) through a laparotomy. CTSH sponge was implanted into the abdominal subcutaneous and a laparotomy was used for blood sampling from abdominal aortic. Several kinds of blood parameters were detected at different time points, which were reflected by coagulation parameters including thrombin time (TT), prothrombin time (PT), activated partial thromboplatin time (APTT), fibrinogen (FIB) and platelet factor 4 (PF4); anticoagulation parameter including antithrombin III (AT-III); fibrinolytic parameters including plasminogen (PLG), fibrin degradation product (FDP) and D-dimer; hemorheology parameters including blood viscosity (BV) and plasma viscosity (PV). Results showed that CTSH sponge has no significant effect on the blood parameters of mice. The data suggested that CTSH sponge can be applied in the field of biomedical materials and has potential possibility to be developed into clinical drugs of hemostatic agents. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessArticle The Use of UV-Visible Reflectance Spectroscopy as an Objective Tool to Evaluate Pearl Quality
Mar. Drugs 2012, 10(7), 1459-1475; doi:10.3390/md10071459
Received: 31 March 2012 / Revised: 17 June 2012 / Accepted: 27 June 2012 / Published: 10 July 2012
Cited by 2 | PDF Full-text (1180 KB) | HTML Full-text | XML Full-text
Abstract
Assessing the quality of pearls involves the use of various tools and methods, which are mainly visual and often quite subjective. Pearls are normally classified by origin and are then graded by luster, nacre thickness, surface quality, size, color and shape. The aim
[...] Read more.
Assessing the quality of pearls involves the use of various tools and methods, which are mainly visual and often quite subjective. Pearls are normally classified by origin and are then graded by luster, nacre thickness, surface quality, size, color and shape. The aim of this study was to investigate the capacity of Artificial Neural Networks (ANNs) to classify and estimate the quality of 27 different pearls from their UV-Visible spectra. Due to the opaque nature of pearls, spectroscopy measurements were performed using the Diffuse Reflectance UV-Visible spectroscopy technique. The spectra were acquired at two different locations on each pearl sample in order to assess surface homogeneity. The spectral data (inputs) were smoothed to reduce the noise, fed into ANNs and correlated to the pearl’s quality/grading criteria (outputs). The developed ANNs were successful in predicting pearl type, mollusk growing species, possible luster and color enhancing, donor condition/type, recipient/host color, donor color, pearl luster, pearl color, origin. The results of this study shows that the developed UV-Vis spectroscopy-ANN method could be used as a more objective method of assessing pearl quality (grading) and may become a valuable tool for the pearl grading industry. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessArticle Isolation, Characterization and Biological Evaluation of Jellyfish Collagen for Use in Biomedical Applications
Mar. Drugs 2011, 9(6), 967-983; doi:10.3390/md9060967
Received: 29 April 2011 / Revised: 20 May 2011 / Accepted: 26 May 2011 / Published: 7 June 2011
Cited by 36 | PDF Full-text (873 KB) | HTML Full-text | XML Full-text
Abstract
Fibrillar collagens are the more abundant extracellular proteins. They form a metazoan-specific family, and are highly conserved from sponge to human. Their structural and physiological properties have been successfully used in the food, cosmetic, and pharmaceutical industries. On the other hand, the increase
[...] Read more.
Fibrillar collagens are the more abundant extracellular proteins. They form a metazoan-specific family, and are highly conserved from sponge to human. Their structural and physiological properties have been successfully used in the food, cosmetic, and pharmaceutical industries. On the other hand, the increase of jellyfish has led us to consider this marine animal as a natural product for food and medicine. Here, we have tested different Mediterranean jellyfish species in order to investigate the economic potential of their collagens. We have studied different methods of collagen purification (tissues and experimental procedures). The best collagen yield was obtained using Rhizostoma pulmo oral arms and the pepsin extraction method (2–10 mg collagen/g of wet tissue). Although a significant yield was obtained with Cotylorhiza tuberculata (0.45 mg/g), R. pulmo was used for further experiments, this jellyfish being considered as harmless to humans and being an abundant source of material. Then, we compared the biological properties of R. pulmo collagen with mammalian fibrillar collagens in cell cytotoxicity assays and cell adhesion. There was no statistical difference in cytotoxicity (p > 0.05) between R. pulmo collagen and rat type I collagen. However, since heparin inhibits cell adhesion to jellyfish-native collagen by 55%, the main difference is that heparan sulfate proteoglycans could be preferentially involved in fibroblast and osteoblast adhesion to jellyfish collagens. Our data confirm the broad harmlessness of jellyfish collagens, and their biological effect on human cells that are similar to that of mammalian type I collagen. Given the bioavailability of jellyfish collagen and its biological properties, this marine material is thus a good candidate for replacing bovine or human collagens in selected biomedical applications. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessArticle Polymer Networks Produced by Marine Diatoms in the Northern Adriatic Sea
Mar. Drugs 2011, 9(4), 666-679; doi:10.3390/md9040666
Received: 25 January 2011 / Revised: 5 April 2011 / Accepted: 7 April 2011 / Published: 21 April 2011
Cited by 10 | PDF Full-text (922 KB) | HTML Full-text | XML Full-text
Abstract
Using high resolution molecular technique of atomic force microscopy, we address the extracellular polymer production of Adriatic diatom Cylindrotheca closterium analyzed at the single cell level and the supramolecular organization of gel phase isolated from the Northern Adriatic macroaggregates. Our results revealed that
[...] Read more.
Using high resolution molecular technique of atomic force microscopy, we address the extracellular polymer production of Adriatic diatom Cylindrotheca closterium analyzed at the single cell level and the supramolecular organization of gel phase isolated from the Northern Adriatic macroaggregates. Our results revealed that extracellular polysaccharides freshly produced by marine diatoms can self-assemble directly to form gel network characteristics of the macroscopic gel phase in the natural aquatorium. Based on the experiments performed with isolated polysaccharide fractions of C. closterium and of macroaggregates gel phase, we demonstrated that the polysaccharide self-assembly into gel network can proceed independent of any bacterial mediation or interaction with inorganic particles. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessArticle Biodegradable and Biocompatible Biomaterial, Polyhydroxybutyrate, Produced by an Indigenous Vibrio sp. BM-1 Isolated from Marine Environment
Mar. Drugs 2011, 9(4), 615-624; doi:10.3390/md9040615
Received: 8 March 2011 / Revised: 31 March 2011 / Accepted: 12 April 2011 / Published: 18 April 2011
Cited by 11 | PDF Full-text (149 KB) | HTML Full-text | XML Full-text
Abstract
Polyhydroxybutyrate (PHB) is one of the polyhydroxyalkanoates (PHAs) which has biodegradable and biocompatible properties. They are adopted in the biomedical field, in, for example, medical implants and drug delivery carriers. This study seeks to promote the production of PHB by Vibrio sp. BM-1,
[...] Read more.
Polyhydroxybutyrate (PHB) is one of the polyhydroxyalkanoates (PHAs) which has biodegradable and biocompatible properties. They are adopted in the biomedical field, in, for example, medical implants and drug delivery carriers. This study seeks to promote the production of PHB by Vibrio sp. BM-1, isolated from a marine environment by improving constituents of medium and implementing an appropriate fermentation strategy. This study successfully developed a glycerol-yeast extract-tryptone (GYT) medium that can facilitate the growth of Vibrio sp. BM-1 and lead to the production of 1.4 g/L PHB at 20 h cultivation. This study also shows that 1.57 g/L PHB concentration and 16% PHB content were achieved, respectively, when Vibrio sp. BM-1 was cultivated with MS-GYT medium (mineral salts-supplemented GYT medium) for 12 h. Both cell dry weight (CDW) and residual CDW remained constant at around 8.2 g/L and 8.0 g/L after the 12 h of cultivation, until the end of the experiment. However, both 16% of PHB content and 1.57 g/L of PHB production decreased rapidly to 3% and 0.25 g/L, respectively from 12 h of cultivation to 40 h of cultivation. The results suggest that the secretion of PHB depolymerase that might be caused by the addition of mineral salts reduced PHB after 12 h of cultivation. However, work will be done to explain the effect of adding mineral salts on the production of PHB by Vibrio sp. BM-1 in the near future. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessArticle Assessing Pearl Quality Using Reflectance UV-Vis Spectroscopy: Does the Same Donor Produce Consistent Pearl Quality?
Mar. Drugs 2010, 8(9), 2517-2525; doi:10.3390/md8092517
Received: 12 August 2010 / Revised: 3 September 2010 / Accepted: 13 September 2010 / Published: 20 September 2010
Cited by 8 | PDF Full-text (294 KB) | HTML Full-text | XML Full-text
Abstract
Two groups of commercial quality (“acceptable”) pearls produced using two donors, and a group of “acceptable” pearls from other donors were analyzed using reflectance UV-Vis spectrophotometry. Three pearls with different colors produced by the same donor showed different absorption spectra. Cream and gold
[...] Read more.
Two groups of commercial quality (“acceptable”) pearls produced using two donors, and a group of “acceptable” pearls from other donors were analyzed using reflectance UV-Vis spectrophotometry. Three pearls with different colors produced by the same donor showed different absorption spectra. Cream and gold colored pearls showed a wide absorption from 320 to about 460 nm, while there was just slight reflectance around 400 nm by the white pearl with a pink overtone. Cream and gold pearls reached a reflectance peak at 560 to 590 nm, while the white pearl with pink overtone showed slightly wider absorption in this region. Both cream and gold pearls showed an absorption peak after the reflectance peak, at about 700 nm for the cream pearl and 750 nm for the gold pearl. Two other pearls produced by the same donor (white with cream overtone and cream with various overtones) showed similar spectra, which differed in their intensity. One of these pearls had very high lustre and its spectrum showed a much higher percentage reflectance than the second pearl with inferior lustre. This result may indicate that reflectance is a useful quantitative indicator of pearl lustre. The spectra of two white pearls resulting from different donors with the same color nacre (silver) showed a reflectance at 260 nm, followed by absorption at 280 nm and another reflectance peak at 340 nm. After this peak the spectra for these pearls remained flat until a slight absorption peak around 700 nm. Throughout the visible region, all white pearls used in this study showed similar reflectance spectra although there were differences in reflectance intensity. Unlike the spectral results from white pearls, the results from yellow and gold pearls varied according to color saturation of the pearl. The results of this study show that similarities between absorption and reflectance spectra of cultured pearls resulting from the same saibo donor are negligible and could not be detected with UV-Vis spectrophotometry. Nevertheless, this technique could have a role to play in developing less subjective methods of assessing pearl quality and in further studies of the relationships between pearl quality and that of the donor and recipient oysters. Full article
(This article belongs to the Special Issue Marine Biomaterials)

Review

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Open AccessReview Magnetotactic Bacteria as Potential Sources of Bioproducts
Mar. Drugs 2015, 13(1), 389-430; doi:10.3390/md13010389
Received: 28 August 2014 / Accepted: 17 December 2014 / Published: 16 January 2015
Cited by 10 | PDF Full-text (1690 KB) | HTML Full-text | XML Full-text
Abstract
Magnetotactic bacteria (MTB) produce intracellular organelles called magnetosomes which are magnetic nanoparticles composed of magnetite (Fe3O4) or greigite (Fe3S4) enveloped by a lipid bilayer. The synthesis of a magnetosome is through a genetically controlled process
[...] Read more.
Magnetotactic bacteria (MTB) produce intracellular organelles called magnetosomes which are magnetic nanoparticles composed of magnetite (Fe3O4) or greigite (Fe3S4) enveloped by a lipid bilayer. The synthesis of a magnetosome is through a genetically controlled process in which the bacterium has control over the composition, direction of crystal growth, and the size and shape of the mineral crystal. As a result of this control, magnetosomes have narrow and uniform size ranges, relatively specific magnetic and crystalline properties, and an enveloping biological membrane. These features are not observed in magnetic particles produced abiotically and thus magnetosomes are of great interest in biotechnology. Most currently described MTB have been isolated from saline or brackish environments and the availability of their genomes has contributed to a better understanding and culturing of these fastidious microorganisms. Moreover, genome sequences have allowed researchers to study genes related to magnetosome production for the synthesis of magnetic particles for use in future commercial and medical applications. Here, we review the current information on the biology of MTB and apply, for the first time, a genome mining strategy on these microorganisms to search for secondary metabolite synthesis genes. More specifically, we discovered that the genome of the cultured MTB Magnetovibrio blakemorei, among other MTB, contains several metabolic pathways for the synthesis of secondary metabolites and other compounds, thereby raising the possibility of the co-production of new bioactive molecules along with magnetosomes by this species. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessReview Marine Origin Collagens and Its Potential Applications
Mar. Drugs 2014, 12(12), 5881-5901; doi:10.3390/md12125881
Received: 1 August 2014 / Revised: 11 November 2014 / Accepted: 19 November 2014 / Published: 5 December 2014
Cited by 15 | PDF Full-text (623 KB) | HTML Full-text | XML Full-text
Abstract
Collagens are the most abundant high molecular weight proteins in both invertebrate and vertebrate organisms, including mammals, and possess mainly a structural role, existing different types according with their specific organization in distinct tissues. From this, they have been elected as one of
[...] Read more.
Collagens are the most abundant high molecular weight proteins in both invertebrate and vertebrate organisms, including mammals, and possess mainly a structural role, existing different types according with their specific organization in distinct tissues. From this, they have been elected as one of the key biological materials in tissue regeneration approaches. Also, industry is constantly searching for new natural sources of collagen and upgraded methodologies for their production. The most common sources are from bovine and porcine origin, but other ways are making their route, such as recombinant production, but also extraction from marine organisms like fish. Different organisms have been proposed and explored for collagen extraction, allowing the sustainable production of different types of collagens, with properties depending on the kind of organism (and their natural environment) and extraction methodology. Such variety of collagen properties has been further investigated in different ways to render a wide range of applications. The present review aims to shed some light on the contribution of marine collagens for the scientific and technological development of this sector, stressing the opportunities and challenges that they are and most probably will be facing to assume a role as an alternative source for industrial exploitation. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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Open AccessReview Understanding Nanocalcification: A Role Suggested for Crystal Ghosts
Mar. Drugs 2014, 12(7), 4231-4246; doi:10.3390/md12074231
Received: 19 June 2014 / Revised: 7 July 2014 / Accepted: 8 July 2014 / Published: 23 July 2014
Cited by 3 | PDF Full-text (1846 KB) | HTML Full-text | XML Full-text
Abstract
The present survey deals with the initial stage of the calcification process in bone and other hard tissues, with special reference to the organic-inorganic relationship and the transformation that the early inorganic particles undergo as the process moves towards completion. Electron microscope studies
[...] Read more.
The present survey deals with the initial stage of the calcification process in bone and other hard tissues, with special reference to the organic-inorganic relationship and the transformation that the early inorganic particles undergo as the process moves towards completion. Electron microscope studies clearly exclude the possibility that these particles might be crystalline structures, as often believed, by showing that they are, instead, organic-inorganic hybrids, each comprising a filamentous organic component (the crystal ghost) made up of acidic proteins. The hypothesis is suggested that the crystal ghosts bind and stabilize amorphous calcium phosphate and that their subsequent degradation allows the calcium phosphate, once released, to acquire a hydroxyapatite, crystal-like organization. A conclusive view of the mechanism of biological calcification cannot yet be proposed; even so, however, the role of crystal ghosts as a template of the structures usually called “crystallites” is a concept that has gathered increasing support and can no longer be disregarded. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessReview Applications of Mass Spectrometry to Structural Analysis of Marine Oligosaccharides
Mar. Drugs 2014, 12(7), 4005-4030; doi:10.3390/md12074005
Received: 13 March 2014 / Revised: 28 April 2014 / Accepted: 6 May 2014 / Published: 30 June 2014
Cited by 3 | PDF Full-text (2359 KB) | HTML Full-text | XML Full-text
Abstract
Marine oligosaccharides have attracted increasing attention recently in developing potential drugs and biomaterials for their particular physical and chemical properties. However, the composition and sequence analysis of marine oligosaccharides are very challenging for their structural complexity and heterogeneity. Mass spectrometry (MS) has become
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Marine oligosaccharides have attracted increasing attention recently in developing potential drugs and biomaterials for their particular physical and chemical properties. However, the composition and sequence analysis of marine oligosaccharides are very challenging for their structural complexity and heterogeneity. Mass spectrometry (MS) has become an important technique for carbohydrate analysis by providing more detailed structural information, including molecular mass, sugar constituent, sequence, inter-residue linkage position and substitution pattern. This paper provides an overview of the structural analysis based on MS approaches in marine oligosaccharides, which are derived from some biologically important marine polysaccharides, including agaran, carrageenan, alginate, sulfated fucan, chitosan, glycosaminoglycan (GAG) and GAG-like polysaccharides. Applications of electrospray ionization mass spectrometry (ESI-MS) are mainly presented and the general applications of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) are also outlined. Some technical challenges in the structural analysis of marine oligosaccharides by MS have also been pointed out. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessReview Evolving Marine Biomimetics for Regenerative Dentistry
Mar. Drugs 2014, 12(5), 2877-2912; doi:10.3390/md12052877
Received: 13 March 2014 / Revised: 14 April 2014 / Accepted: 16 April 2014 / Published: 13 May 2014
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Abstract
New products that help make human tissue and organ regeneration more effective are in high demand and include materials, structures and substrates that drive cell-to-tissue transformations, orchestrate anatomical assembly and tissue integration with biology. Marine organisms are exemplary bioresources that have extensive possibilities
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New products that help make human tissue and organ regeneration more effective are in high demand and include materials, structures and substrates that drive cell-to-tissue transformations, orchestrate anatomical assembly and tissue integration with biology. Marine organisms are exemplary bioresources that have extensive possibilities in supporting and facilitating development of human tissue substitutes. Such organisms represent a deep and diverse reserve of materials, substrates and structures that can facilitate tissue reconstruction within lab-based cultures. The reason is that they possess sophisticated structures, architectures and biomaterial designs that are still difficult to replicate using synthetic processes, so far. These products offer tantalizing pre-made options that are versatile, adaptable and have many functions for current tissue engineers seeking fresh solutions to the deficiencies in existing dental biomaterials, which lack the intrinsic elements of biofunctioning, structural and mechanical design to regenerate anatomically correct dental tissues both in the culture dish and in vivo. Full article
(This article belongs to the Special Issue Marine Biomaterials)
Open AccessReview Chemical Structures and Bioactivities of Sulfated Polysaccharides from Marine Algae
Mar. Drugs 2011, 9(2), 196-223; doi:10.3390/md9020196
Received: 22 December 2010 / Revised: 15 January 2011 / Accepted: 26 January 2011 / Published: 8 February 2011
Cited by 247 | PDF Full-text (220 KB) | HTML Full-text | XML Full-text
Abstract
Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal
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Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal biomaterials. In particular, it will provide an update on the structural chemistry of the major sulfated polysaccharides synthesized by seaweeds including the galactans (e.g., agarans and carrageenans), ulvans, and fucans. It will then review the recent findings on the anticoagulant/antithrombotic, antiviral, immuno-inflammatory, antilipidemic and antioxidant activities of sulfated polysaccharides and their potential for therapeutic application. Full article
(This article belongs to the Special Issue Marine Biomaterials)
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