scholarly journals Inheritance of physico-chemical properties and ROS generation by carbon quantum dots derived from pyrolytically carbonized bacterial sources

2021 ◽  
pp. 100151
Author(s):  
Yanyan Wu ◽  
Hao Wei ◽  
Henny C. van der Mei ◽  
Joop de Vries ◽  
Henk J. Busscher ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Chemical Properties ◽  
Carbon Quantum Dots ◽  
Ros Generation ◽  
Physico Chemical ◽  
Bacterial Sources

scholarly journals Synergy between “Probiotic” Carbon Quantum Dots and Ciprofloxacin in Eradicating Infectious Biofilms and Their Biosafety in Mice

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1809
Author(s):  
Yanyan Wu ◽  
Guang Yang ◽  
Henny C. van der Mei ◽  
Linqi Shi ◽  
Henk J. Busscher ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Open Space ◽  
Carbon Quantum Dots ◽  
Probiotic Bacteria ◽  
Ros Generation ◽  
E Coli ◽  
Protein Levels ◽  
Reactive Protein ◽  
Physico Chemical ◽  
Intestinal Infections

Orally administrated probiotic bacteria can aid antibiotic treatment of intestinal infections, but their arrival at their intestinal target site is hampered by killing in the gastrointestinal tract and by antibiotics solely intended for pathogen killing. Carbon-quantum-dots are extremely small nanoparticles and can be derived from different sources, including bacteria. Here, we hypothesize that carbon-quantum-dots inherit antibacterial activity from probiotic source bacteria to fulfill a similar role as live probiotics in intestinal infection therapy. Physico-chemical analyses indicated that carbon-quantum-dots, hydrothermally derived from Bifidobacterium breve (B-C-dots), inherited proteins and polysaccharides from their source-bacteria. B-C-dots disrupted biofilm matrices of Escherichia coli and Salmonella typhimurium biofilms through extensive reactive-oxygen-species (ROS)-generation, causing a decrease in volumetric bacterial-density in biofilms. Decreased bacterial densities leave more open space in biofilms and have enhanced ciprofloxacin penetration and killing potential in an E. coli biofilm pre-exposed to probiotic B-C-dots. Pathogenic carbon-quantum-dots hydrothermally derived from E. coli (E-C-dots) did not disrupt pathogenic biofilms nor enhance E. coli killing potential by ciprofloxacin. B-C-dots were biosafe in mice upon daily administration, while E-C-dots demonstrated a decrease in white blood cell and platelet counts and an increase in C-reactive protein levels. Therefore, the way is paved for employing probiotic carbon-quantum-dots instead of viable, probiotic bacteria for synergistic use with existing antibiotics in treating intestinal infections.

scholarly journals Carbon Quantum Dots Derived from Different Carbon Sources for Antibacterial Applications

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 623
Author(s):  
Yanyan Wu ◽  
Cong Li ◽  
Henny C. van der Mei ◽  
Henk J. Busscher ◽  
Yijin Ren
Keyword(s):  
Quantum Dots ◽  
Large Scale ◽  
Bacterial Resistance ◽  
Carbon Sources ◽  
Antibacterial Activities ◽  
Carbon Quantum Dots ◽  
Ros Generation ◽  
Physico Chemical ◽  
The Matrix ◽  
Natural Carbon

Nanoparticles possess unique features due to their small size and can be composed of different surface chemistries. Carbon quantum dots possess several unique physico-chemical and antibacterial activities. This review provides an overview of different methods to prepare carbon quantum dots from different carbon sources in order to provide guidelines for choosing methods and carbon sources that yield carbon quantum dots with optimal antibacterial efficacy. Antibacterial activities of carbon quantum dots predominantly involve cell wall damage and disruption of the matrix of infectious biofilms through reactive oxygen species (ROS) generation to cause dispersal of infecting pathogens that enhance their susceptibility to antibiotics. Quaternized carbon quantum dots from organic carbon sources have been found to be equally efficacious for controlling wound infection and pneumonia in rodents as antibiotics. Carbon quantum dots derived through heating of natural carbon sources can inherit properties that resemble those of the carbon sources they are derived from. This makes antibiotics, medicinal herbs and plants or probiotic bacteria ideal sources for the synthesis of antibacterial carbon quantum dots. Importantly, carbon quantum dots have been suggested to yield a lower chance of inducing bacterial resistance than antibiotics, making carbon quantum dots attractive for large scale clinical use.

Biocompatible Carbon Nanodots for Functional Imaging and Cancer Therapy

2018 ◽  
Vol 7 (2) ◽  
pp. 31-45 ◽  
Author(s):  
Alexandre Roumenov Loukanov ◽  
Hristo Stefanov Gagov ◽  
Milena Yankova Mishonova ◽  
Seiichiro Nakabayashi
Keyword(s):  
Drug Delivery ◽  
Quantum Dots ◽  
Cancer Therapy ◽  
Organic Dyes ◽  
Chemical Properties ◽  
Carbon Quantum Dots ◽  
Photon Absorption ◽  
Carbon Nanodots ◽  
Two Photon ◽  
Bio Imaging

This article describes how carbon quantum dots (C-dots) are tiny carbon nanoparticles (less than 10 nm in size) being envisaged to be used in bio-sensing, bio-imaging and drug delivery nanosystems. Their low toxicity and stable chemical properties make them suitable candidates for new types of fluorescent probe, which overcome the common drawbacks of previous fluorescent probes (organic dyes and inorganic quantum dots). In addition, fluorescent C-dots possess a rather strong ability to bind with other organic and inorganic molecules due to their abundant surface groups. For that reason, fluorescent C-dots can be manipulated via series of controllable chemical treatments in order to satisfy the demands in the photocatalytic, biochemical and chemical sensing, bio-imaging, drug delivery and enhanced cell targeting. In recent studies it was described the development of carbon quantum dots with large two-photon absorption cross sections towards two-photon imaging for use in photodynamic cancer therapy. Thus, C-dots have become a rising star in biomedical research with a promising future for the application in nanomedicine.

Quantum Dots as Promising Theranostic Tools Against Amyloidosis: A Review

2019 ◽  
Vol 26 (8) ◽  
pp. 555-563 ◽  
Author(s):  
M.P. Taraka Prabhu ◽  
Nandini Sarkar
Keyword(s):  
Quantum Dots ◽  
Fluorescence Emission ◽  
Chemical Properties ◽  
Type Ii Diabetes Mellitus ◽  
Nano Particles ◽  
Polymerization Process ◽  
Condensation Polymerization ◽  
Medical Sciences ◽  
Amyloid Fibril Formation ◽  
Physico Chemical

Amyloids are highly ordered beta sheet rich stable protein aggregates, which have been found to play a significant role in the onset of several degenerative diseases such as Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, Type II diabetes mellitus and so on. Aggregation of proteins leading to amyloid fibril formation via intermediate(s), is thought to be a nucleated condensation polymerization process associated with many pathological conditions. There has been extensive research to identify inhibitors of these disease oriented aggregation processes. In recent times, quantum dots, with their unique physico-chemical properties have grabbed the attention of scientific community due to its applications in medical sciences. Quantum dots are nano-particles usually made of semiconductor materials which emit fluorescence upon radiation. The wavelength of fluorescence emission varies with changes in size of quantum dots. Several studies have reported significant inhibitory effects of these quantum dots towards amyloidogenesis, thereby presenting themselves as promising candidates against amyloidosis. Further, studies have also revealed amyloid detection capacity of quantum dots with sensitivity and specificity better than conventional probes. In the current review, we will discuss the various effects of quantum dots on protein aggregation pathways, their mechanism of actions and their potentials as effective therapeutics against amyloidosis.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

Physico-chemical properties of the rare-earth metals, scandium, and yttrium

1963 ◽  
Vol 79 (2) ◽  
pp. 263-293 ◽  
Author(s):  
E.M. Savitskii ◽  
V.F. Terekhova ◽  
O.P. Naumkin
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Chemical Properties ◽  
Physico Chemical ◽  
The Rare Earth
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