A Novel Approach for Quantifying Magnetic Susceptibility of Aqueous and Organic Solutions.

A new method for measuring the magnetic properties of aqueous and organic solutions is presented. This approach is based on quantifying the force resulting from the sample's interaction with a magnetic field. The experimental setup utilizes neodymium magnets attached to a stepper motor to adjust the distance between the magnets and the test sample, while an analytical balance serves as a strain gauge. Magnetic susceptibility measurements were performed on selected inorganic and organic solutions. A series of finite element simulations allowed us to convert experimental results to physical quantities describing magnetic susceptibilities of substances. The limit of detection (LoD) and limit of quantification (LoQ) values for the developed method of determining magnetic susceptibility were equal to 6.67·10-3 M and 2.02·10-2 M, respectively.

Synergistic Enhancement of Diagnostic Imaging: Synthesis and Preliminary Safety Evaluation of Gadolinium-Doped Carbon Quantum Dots as Dual-Contrast Agent.

The present study explores the synthesis and bio-safety evaluation of gadolinium-doped carbon quantum dots (GCQDs) as a potential dual-contrast agent for diagnostic imaging. GCQDs exhibit both fluorescent and magnetic properties, making them suitable for UV-Vis and magnetic resonance imaging (MRI). The synthesis of GCQDs was achieved via hydrothermal treatment, incorporating gadolinium into the carbon quantum dot matrix. The magnetic properties of GCQDs were analyzed, showing significantly enhanced values compared to gadobutrol, a common MRI contrast agent. However, synthesis constraints limit the gadolinium content achievable in nanodots. To assess the safety of GCQDs, their effects on the embryonic development of zebrafish (Danio rerio) were examined. Various concentrations of GCQDs were tested, observing mortality rates, hatchability, malformations, heartbeats, spontaneous movement, and GCQDs uptake. Dialysis studies indicated that gadolinium ions are incorporated into the internal structure of the carbon nanodots. Zebrafish toxicity tests revealed that while survival rates were comparable to control groups, hatchability decreased significantly with higher gadolinium concentrations in GCQDs. Fluorescence microscopy showed no statistical differences in the fluorescence intensity between groups. These findings suggest that GCQDs could serve as an effective dual-contrast agent, combining the optical imaging capabilities of CQDs with the enhanced MRI contrast provided by gadolinium. This study underscores the need for further research on the synthesis methods and biological interactions of GCQDs to ensure their safety and efficacy in medical applications.

Milk-Derived Carbon Quantum Dots: Study of Biological and Chemical Properties Provides Evidence of Toxicity.

Carbon dots (CDs) are carbon-based zero-dimensional nanomaterials that can be prepared from a number of organic precursors. In this research, they are prepared using fat-free UHT cow milk through the hydrothermal method. FTIR analysis shows C=O and C-H bond presence, as well as nitrogen-based bond like C-N, C=N and -NH2 presence in CDs, while the absorption spectra show the absorption band at 280 ± 3 nm. Next, the Biuret test was performed, with the results showing no presence of unreacted proteins in CDs. It can be said that all proteins are converted in CDs. Photo luminance spectra shows the emission of CDs is 420 nm and a toxicity study of CDs was performed. The Presto Blue method was used to test the toxicity of CDs for murine hippocampal cells. CDs at a concentration of 4 mg/mL were hazardous independent of synthesis time, while the toxicity was higher for lower synthesis times of 1 and 2 h. When the concentration is reduced in 1 and 2 h synthesized CDs, the cytotoxic effect also decreases significantly, ensuring a survival rate of 60-80%. However, when the synthesis time of CDs is increased, the cytotoxic effect decreases to a lesser extent. The CDs with the highest synthesis time of 8 h do not show a cytotoxic effect above 60%. The cytotoxicity study shows that CDs may have a concentration and time-dependent cytotoxic effect, reducing the number of viable cells by 40%.

The Mechanism of Adsorption of Rh(III) Bromide Complex Ions on Activated Carbon.

In the paper, the mechanism of the process of the Rh(III) ions adsorption on activated carbon ORGANOSORB 10-AA was investigated. It was shown, that the process is reversible, i.e., stripping of Rh(III) ions from activated carbon to the solution is also possible. This opens the possibility of industrial recovery of Rh (III) ions from highly dilute aqueous solutions. The activation energies for the forward and backward reaction were determined These are equal to c.a. 7 and 0 kJ/mol. respectively. Unfortunately, the efficiency of this process was low. Obtained maximum load of Rh(III) was equal to 1.13 mg per 1 g of activated carbon.

Synthesis and Catalytic Study of NiAg Bimetallic Core-Shell Nanoparticles.

This publication presents the synthesis of core-shell nanoparticles, where the core was Ni, and the shell was a Ag-Ni nano alloy. The synthesis was based on the reduction of Ni and Ag ions with sodium borohydride in the presence of trisodium citrate as a stabilizer. In order to determine the phase composition of the obtained nanoparticles, an XRD study was performed, and in order to identify the oxidation states of the nanoparticle components, an XPS spectroscopic study was performed. The composition and shape of the particles were determined using the HR-TEM EDS test. The obtained nanoparticles had a size of 11 nm. The research on catalytic properties was carried out in the model methylene blue reduction system. The investigation of the catalytic activity of colloids was carried out with the use of UV-Vis spectrophotometry. The Ag-Ni alloy was about ten times more active than were pure silver nanoparticles of a similar size.

The Influence of Caramel Carbon Quantum Dots and Caramel on Platelet Aggregation, Protein Glycation and Lipid Peroxidation.

Caramel, defined as a coloring agent and as an antioxidant, is used in several kinds of food products and is consumed by many people in different amounts. In our research we showed that the caramelization of sucrose under special conditions leads to the formation of carbon quantum dots (CQDs). So, it makes sense that humans also consume this type of CQDs, and it is theoretically possible for these particles to affect the body. Despite an increasing number of studies describing different types of CQDs, their biosafety is still not clearly understood. In our in vitro research, we examined the effects on platelet aggregation, protein glycation and lipid peroxidation of CQDs and caramel formed from a 20% sucrose solution. In vitro aggregation tests were conducted using freshly collected whole rat blood in a multiplate platelet function analyzer and measurer of electric impedance. The cytotoxic effect of the tested solutions on blood platelets was evaluated based on the release of lactate dehydrogenase. The formation of glycated bovine serum albumin was measured as fluorescence intensity and fructosamine level. The reducing power of the solutions was determined in adipose tissue, and their effect on lipid peroxidation in adipose tissue in vitro was also assessed. By measuring the intensity of hemolysis after incubation in solutions with red blood cell, we assessed their influence on the integration of the red blood cell membrane. All tests were performed in comparison with glucose and fructose and other frequently used sweeteners, such as erythritol and xylitol. Our study showed that caramel and CQDs formed from caramel may influence the glycation process and integrity of the red blood cell membrane, but unlike glucose and fructose, they decrease lipid peroxidation and may reduce Fe (III). Additionally, it is unlikely that they affect platelet aggregation. Compared to glucose and fructose, they may be safer for patients with metabolic disorders; however, further research is needed on the safety and biological activity of caramel and CQD.