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Advanced Healthcare Materials Oct 2018Diatoms are unicellular photosynthetic algae enclosed in porous 3D nanopatterned silica enclosures called "frustules." The diatom frustules are made from biosilica... (Review)
Review
Diatoms are unicellular photosynthetic algae enclosed in porous 3D nanopatterned silica enclosures called "frustules." The diatom frustules are made from biosilica self-assembled into intricate porous shells that feature unique properties including high specific surface area, biocompatibility, tailorable surface chemistry, thermal stability, and high mechanical and chemical resistance. The ability to cultivate diatoms in artificial environments and their abundant availability of diatom frustules as mineable fossilized mineral deposits (diatomite or diatomaceous earth; DE) make diatom silica a promising natural alternative to synthetic porous silica for a broad range of biomedical, environmental, agricultural, and energy applications. This review article provides a comprehensive and current account of the use of natural DE silica materials in biomedical applications focused mainly on drug delivery with some highlights on biosensing, tissue engineering, and clotting agents. The article also covers some basic physical and chemical aspects of DE material such as purification, surface chemical functionalization, biocompatibility, and cellular uptake that are critical for the development of an efficient drug carrier.
Topics: Diatoms; Drug Carriers; Drug Delivery Systems; Porosity; Silicon Dioxide
PubMed: 30118185
DOI: 10.1002/adhm.201800552 -
Molecules (Basel, Switzerland) Dec 2023Heparin, a highly sulfated glycosaminoglycan, is a naturally occurring anticoagulant that plays a vital role in various physiological processes. The remarkable...
Heparin, a highly sulfated glycosaminoglycan, is a naturally occurring anticoagulant that plays a vital role in various physiological processes. The remarkable structural complexity of heparin, consisting of repeating disaccharide units, makes it a crucial molecule for the development of commercial drugs in the pharmaceutical industry. Over the past few decades, significant progress has been made in the development of cost-effective adsorbents specifically designed for the adsorption of heparin from porcine intestinal mucosa. This advancement has been driven by the need for efficient and scalable methods to extract heparin from natural sources. In this study, we investigated the use of cationic ammonium-functionalized diatomaceous earth, featuring enhanced porosity, larger surface area, and higher thermal stability, to maximize the isolated heparin recovery. Our results showed that the higher cationic density and less bulky quaternary modified diatomaceous earth (QDADE) could adsorb up to 16.3 mg·g (31%) of heparin from the real mucosa samples. Additionally, we explored the conditions of the adsorbent surface for recovery of the heparin molecule and optimized various factors, such as temperature and pH, to optimize the heparin uptake. This is the introductory account of the implementation of modified diatomaceous earth with quaternary amines for heparin capture.
Topics: Animals; Swine; Diatomaceous Earth; Heparin; Anticoagulants; Temperature; Intestinal Mucosa
PubMed: 38138471
DOI: 10.3390/molecules28247982 -
International Journal of Molecular... Aug 2022A neoteric round sieve diatomite (De) decorated with sea-urchin-like alpha-type iron trioxide (α-FeO) synthetics was prepared by the hydrothermal method and further...
A neoteric round sieve diatomite (De) decorated with sea-urchin-like alpha-type iron trioxide (α-FeO) synthetics was prepared by the hydrothermal method and further calcination. The results of the electromagnetic (EM) parameters of α-FeO-decorated De (α-FeO@D) showed that the minimum reflection loss (RL) of α-FeO@D could reach -54.2 dB at 11.52 GHz and the matched absorber thickness was 3 mm. The frequency bandwidth corresponding to the microwave RL value below -20 dB was up to 8.24 GHz (9.76-18 GHz). This indicates that α-FeO@D composite can be a lightweight and stable material; because of the low density of De (1.9-2.3 g/cm), the density of α-FeO@D composite material is lower than that of α-FeO (5.18 g/cm). We found that the combination of the magnetic loss of sea-urchin-like α-FeO and the dielectric loss of De has the most dominant role in electromagnetic wave absorption and loss. We focused on comparing the absorbing properties before and after the formation of sea-urchin-like α-FeO and explain in detail the effects of the structure and crystal shape of this novel composite on the absorbing properties.
Topics: Diatomaceous Earth; Microwaves
PubMed: 36012621
DOI: 10.3390/ijms23169362 -
Materials (Basel, Switzerland) Feb 2022In this study, the potential use of waste diatomaceous earth from the production of diatomaceous earth for filtration purposes, as an alternative raw material for foam...
In this study, the potential use of waste diatomaceous earth from the production of diatomaceous earth for filtration purposes, as an alternative raw material for foam glass production, was explored. The chemical and mineralogical composition and the high temperature behavior of waste diatomite were studied to assess its suitability for foam glass production. Glass-ceramic foams were prepared using NaOH solution as a foaming agent, via a hydrate mechanism. The influence of different pretreatments and firing temperatures on the foam's structure, bulk density and compressive strength was investigated. High temperature behavior was studied using TG/DTA analysis and high temperature microscopy. Phase composition was studied using X-ray diffraction analysis. Glass-ceramic foam samples of a high porosity comparable to conventional foam glass products were fabricated. The pretreatment temperature, foaming temperature and sintering holding time were found to have a significant influence on foam properties. With increased pretreatment temperature, pyrogenic carbon from the thermal decomposition of organic matter contained in the raw material acted as an additional foaming agent and remained partially unoxidized in prepared foams. The bulk densities of prepared samples ranged from 150 kg/m to 510 kg/m and their compressive strengths were between 140 and 1270 kPa.
PubMed: 35207924
DOI: 10.3390/ma15041384 -
Molecules (Basel, Switzerland) Dec 2021Nowadays, we are tackling various issues related to the overuse of synthetic insecticides. Growing concerns about biodiversity, animal and human welfare, and food... (Review)
Review
Nowadays, we are tackling various issues related to the overuse of synthetic insecticides. Growing concerns about biodiversity, animal and human welfare, and food security are pushing agriculture toward a more sustainable approach, and research is moving in this direction, looking for environmentally friendly alternatives to be adopted in Integrated Pest Management (IPM) protocols. In this regard, inert dusts, especially diatomaceous earths (DEs), hold a significant promise to prevent and control a wide range of arthropod pests. DEs are a type of naturally occurring soft siliceous sedimentary rock, consisting of the fossilized exoskeleton of unicellular algae, which are called diatoms. Mainly adopted for the control of stored product pests, DEs have found also their use against some household insects living in a dry environment, such as bed bugs, or insects of agricultural interest. In this article, we reported a comprehensive review of the use of DEs against different arthropod pest taxa, such as Acarina, Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, Ixodida, Lepidoptera, when applied either alone or in combination with other techniques. The mechanisms of action of DEs, their real-world applications, and challenges related to their adoption in IPM programs are critically reported.
Topics: Animals; Arthropods; Diatomaceous Earth; Insect Control; Insecticides
PubMed: 34946567
DOI: 10.3390/molecules26247487 -
Animals : An Open Access Journal From... Feb 2019Fossil shell flour (FSF), also known as Diatomaceous earth, or diatomite, consists of amorphous silicates with important physical and chemical characteristics, including... (Review)
Review
Fossil shell flour (FSF), also known as Diatomaceous earth, or diatomite, consists of amorphous silicates with important physical and chemical characteristics, including porosity and permeability, low density and thermal conductivity, tiny particle size, high surface area, solubility, hydrophobia, and absorption capabilities, which are molecular filter actors, substituting their integral cations without physical changes. The substance is nontoxic, cheap, and readily available in large quantity in many countries. Recently, FSF has been modified as additives for several uses. Recent studies have supported its use as animal growth promoter, vaccine adjuvant in livestock, water purifier, mycotoxin binder, inert dust applications in stored-pest management, pesticide, animal feed additive, as a natural source of silicon in livestock and as natural anthelmintic. Numerous advantages of FSF include its low-cost and availability, its nontoxic characteristics, and the fact that food grade diatomaceous earth is safe for human consumption. In this paper, we review the main uses of FSF in the livestock industry, with reference to similar works earlier published that elucidate their important roles.
PubMed: 30813550
DOI: 10.3390/ani9030070 -
Biotechnology Advances Nov 2022Phospholipids are unique and versatile molecules, essential in a variety of biological systems. Moreover, their diverse structures and amphiphilic properties endorse... (Review)
Review
Phospholipids are unique and versatile molecules, essential in a variety of biological systems. Moreover, their diverse structures and amphiphilic properties endorse their indispensable and unparalleled roles in research and industrial-related applications. However, in most cases of applications, naturally occurring phospholipids are either deficit in structural variety or insufficient in quantity; therefore, novel methods must be developed for the synthesis of new molecules or modification of natural structures. To identify sustainable and environmentally friendly approaches, this work reviews the latest progress in the acquisition of structurally defined phospholipids (designer phospholipids) from natural resources, including structural retrieval, redesign and synthesis of designer phospholipids via chemo-/enzymatic approaches. This review additionally highlights the opportunity to use biological systems to direct the production of specific phospholipid species through genetic engineering via defined metabolic pathways, and functionalization of natural phospholipids through synthetic modifications: substitutions, removals or additions of specific functional groups. A particular focus is given to the establishment of chemical and biological systems for the synthesis of isotopically labelled phospholipids for biomedical applications. The application of green chemistry principles in semi-synthesis of phospholipids including extended use of greener biocatalysts and diatomaceous earth and reduced use of hazardous and toxic solvents is also summarized.
Topics: Diatomaceous Earth; Phospholipids; Solvents
PubMed: 35914627
DOI: 10.1016/j.biotechadv.2022.108025 -
Environmental Science and Pollution... Feb 2021In the present study, we evaluated the insecticidal efficacy of diatomaceous earth (DE) and pirimiphos-methyl for the control of phosphine-susceptible and...
In the present study, we evaluated the insecticidal efficacy of diatomaceous earth (DE) and pirimiphos-methyl for the control of phosphine-susceptible and phosphine-resistant populations of Tribolium castaneum (Herbst) and Sitophilus oryzae (L.). Insecticides were applied on wheat or rice at two doses: DE was applied at 1000 and 2000 ppm and pirimiphos-methyl at 1 and 5 ppm. Adult mortality was measured after 7, 14, and 21 days of exposure, and progeny production capacity on the treated substrates was evaluated 65 days later. For T. castaneum, we found that DE, at 2000 ppm, was able to provide 100% control of two of the three populations tested, while for the third population mortality reached only 84%. Similarly, there were differences in mortality levels after exposure to DE-treated grains between the two S. oryzae populations tested. At 1 ppm, pirimiphos-methyl was not effective for any of the T. castaneum populations tested, but complete mortality was recorded for all populations at 5 ppm. In general, populations of S. oryzae were more susceptible than those of T. castaneum, for both commodities. Our data indicate that both insecticides can be used with success in phosphine resistance management programs, but there are populations of a given species that may be less susceptible, which constitutes a preliminary screening essential.
PubMed: 33635464
DOI: 10.1007/s11356-021-12971-1 -
Frontiers in Veterinary Science 2022Water is one of the primary vectors for African swine fever virus (ASFV) transmission among swine herds. However, the low concentrations of ASFV in water represent a...
Water is one of the primary vectors for African swine fever virus (ASFV) transmission among swine herds. However, the low concentrations of ASFV in water represent a challenge for the detection of the virus by conventional PCR methods, and enrichment of the virus would increase the test sensitivity. In this study, aiming to enrich ASFV in water quickly and efficiently, a rapid and efficient water-borne virus enrichment system (MDEF, modified diatomaceous earth by ferric hydroxide colloid) was used to enrich ASFV in water. After enrichment by MDEF, conventional real-time PCR (qPCR) was used for ASFV detection. ASFV were inactivated and diluted in 10 L of water, of which 4 mL were collected after 60 min treatment using the MDEF system. Two thousand five hundred times reduction of the sample volume was achieved after enrichment. A high adsorption rate of about 99.99 (±0.01)% and a high recovery rate of 64.01 (±10.20)% to 179.65 (±25.53)% was achieved by using 1g modified diatomaceous earth for 10 L ASFV contaminated water. The limit of qPCR detection of ASFV decreased to 1 × 10 GU ml (genomic units per milliliter) from 1 × 10 GU ml after concentrating the spiked water from 10 L to 4 ml. Preliminary application of MDEF allowed successful detection of African swine fever virus (ASFV), porcine circovirus type 2 (PCV2), and pseudorabies virus (PRV) in sewage. Thus, the combination of modified diatomaceous earth and real-time PCR is a promising strategy for the detection of viruses in water.
PubMed: 36619955
DOI: 10.3389/fvets.2022.1045190 -
Journal of Food Protection Jan 2021Almonds rejected as inedible are often used for production of almond oil. However, low-quality almonds are frequently contaminated with aflatoxins, and little is known...
ABSTRACT
Almonds rejected as inedible are often used for production of almond oil. However, low-quality almonds are frequently contaminated with aflatoxins, and little is known regarding transfer of aflatoxins to almond oil during processing. In this study, oil was produced from reject almonds by hexane extraction. Of 19 almond samples that were naturally contaminated with aflatoxins, 17 oil samples contained measurable amounts of aflatoxins, and aflatoxin content of contaminated oil was correlated with aflatoxin content of the nuts. However, oil aflatoxin levels were not correlated with the oxidation level of the oil as measured by percent free fatty acids and peroxide value. Adsorbents used in oil refining were tested for their ability to remove aflatoxins from contaminated oil. Fuller's earth and bentonite were the most effective, removing 96 and 86% of total aflatoxins from contaminated oil samples, respectively. Treatment with diatomaceous earth, in contrast, had no effect on aflatoxin levels in oil. These results show that oil refining steps using mineral clay adsorbents may also function to remove aflatoxins from contaminated oil.
Topics: Aflatoxins; Nuts; Plant Oils; Prunus dulcis
PubMed: 32882027
DOI: 10.4315/JFP-20-229