Blood Plasma Proteins Research Articles

The effect of ethyl alcohol solution with a reduced content of deuterium on the development of chronic alcohol intoxication in the experiment

Background. Protium/deuterium isotope exchange reactions can have a significant effect on the metabolic systems of cells and the whole organism. An imbalance in isotope homeostasis can have both a protective and a negative effect under various pathological conditions.
 Aim. To determine the nature of the influence of an ethyl alcohol solution with a reduced content of deuterium on the development of chronic alcohol intoxication in rats.
 Material and methods. The study was performed on five groups of rats, 10 animals in each: the first group control, the second and third groups alcoholization for 1 month, the fourth and fifth groups alcoholization for 2 months. At the same time, rats of the third and fifth groups received a solution of ethyl alcohol with a reduced content of deuterium. For the development of alcohol intoxication, the animals received a 10% ethanol solution in the 1st week, a 20% solution in the 2nd week, and a 30% ethanol solution starting from the 3rd week. Water with a reduced content of deuterium was obtained using an installation developed at the Kuban State University by the method of electrolytic separation. In the blood plasma of laboratory animals, markers of cytolysis (activity of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase) and oxidative stress (content of thiol groups, glutathione concentration, activity of catalase, glutathione peroxidase, and glutathione reductase) were determined. To analyze the data, nonparametric KruskalWallis and MannWhitney tests were used, which were calculated using the StatPlus program.
 Results. As a result of the studies, it was found that the activity of alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase against the background of ethyl alcohol introduction to animals in water with a reduced content of deuterium during 2 months of the experiment was increased to the level of median values of 51.7; 65.7 and 174.8 U/l, respectively. These indicators statistically significantly exceeded the values of similar parameters of the groups of rats treated with alcohol solution in ordinary distilled water by 22% (p=0.0129), 45% (p=0.0236) and 55% (p=0.0123), respectively. In the study of the SH-groups level (0.29 u.o.d.100/g of protein) in blood plasma and the concentration of glutathione (1.46 mol/ml) in the erythrocyte suspension in animals of the fifth group, values that were reduced relative to the fourth groups by 1217% were determined.
 Conclusion. Isotopic modification of an ethanol solution, aimed at reducing the level of deuterium, is accompanied by a more severe course of chronic alcohol intoxication; this is confirmed by the greater severity of the cytolytic syndrome and the imbalance of the antioxidant system.

Hacking techniques improve health and nutritional status of nestling White-tailed Eagles.

Birds of prey frequently feature in reintroductions and the hacking technique is typically used. Hacking involves removing large nestlings from donor populations, transferring them to captivity, feeding them ad libitum. Potentially, via the hacking method, the stress of captivity and disruption of parental feeding may be detrimental. Alternatively, the provision of ad libitum food may be advantageous. Although hacking has underpinned reintroduction project successes there has been no research on how the method may affect the health and nutritional status of translocated birds during captivity. We compared blood chemistry data from 55 young White-tailed Eagles, translocated from Norway as part of the species' reintroduction to Scotland, from sampling soon after arriving in captivity and again (≈42 days later) before their release. Numerous significant differences between the first and second samples were found, but no significant interactions showed that the sexes responded similarly to captivity. According to hematological and biochemical metrics, individuals showed several changes during captivity, including in red blood cell parameters, plasma proteins, and white cellular parameters related to the immune system, that indicated improved health status. Captivity with ad libitum food was associated with decreased urea and uric acid values: high values can indicate nutritional stress. Urea values became more normally distributed before release, indicating that ad libitum food had reduced nutritional differences between early nestlings in the season and later ones. Despite plentiful food, both sexes lost body mass before release, suggesting an inherent physiological mechanism to improve flight performance in fledglings. We conclude that hacking improved the health and nutritional status of released eagles which is likely to enable birds to cope with greater costs of exploratory behavior which they may require in reintroduction projects. In this context, we note the absence of survival differences between hacked and wild raptors in previous research.

Developmental changes in the extent of drug binding to rat plasma proteins

Binding of therapeutics to proteins in blood plasma is important in influencing their distribution as it is their free (unbound) form that is able to cross cellular membranes to enter tissues and exert their actions. The concentration and composition of plasma proteins vary during pregnancy and development, resulting in potential changes to drug protein binding. Here, we describe an ultrafiltration method to investigate the extent of protein binding of six drugs (digoxin, paracetamol, olanzapine, ivacaftor, valproate and lamotrigine) and two water soluble inert markers (sucrose and glycerol) to plasma proteins from pregnant and developing rats. Results showed that the free fraction of most drugs was lower in the non-pregnant adult plasma where protein concentration is the highest. However, plasma of equivalent protein concentration to younger pups obtained by diluting adult plasma did not always exhibit the same extent of drug binding, reinforcing the likelihood that both concentration and composition of proteins in plasma influence drug binding. Comparison between protein binding and brain drug accumulation in vivo revealed a correlation for some drugs, but not others. Results suggests that plasma protein concentration should be considered when using medications in pregnant and paediatric patients to minimise potential for fetal and neonatal drug exposure.

Interactions of fentanyl with blood platelets and plasma proteins: platelet sensitivity to prasugrel metabolite is not affected by fentanyl under in vitro conditions

BackgroundClinical trials indicate that fentanyl, like morphine, may impair intestinal absorption and thus decrease the efficacy of oral P2Y12 inhibitors, such as clopidogrel, ticagrelor, and prasugrel. However, the ability of fentanyl to directly negate or reduce the inhibitory effect of P2Y12 receptor antagonists on platelet function has not been established. A series of in vitro experiments was performed to investigate the ability of fentanyl to activate platelets, potentiate platelet response to ADP, and/or diminish platelet sensitivity to prasugrel metabolite (R-138727) in agonist-stimulated platelets. The selectivity and specificity of fentanyl toward major carrier proteins has been also studied.MethodsBlood was obtained from healthy volunteers (19 women and 12 men; mean age 40 ± 13 years). Platelet function was measured in whole blood, platelet-rich plasma and in suspensions of isolated platelets by flow cytometry, impedance and optical aggregometry. Surface plasmon resonance and molecular docking were employed to determine the binding kinetics of fentanyl to human albumin, α1-acid glycoprotein, apolipoprotein A-1 and apolipoprotein B-100.ResultsWhen applied at therapeutic and supratherapeutic concentrations under various experimental conditions, fentanyl had no potential to stimulate platelet activation and aggregation, or potentiate platelet response to ADP, nor did it affect platelet susceptibility to prasugrel metabolite in ADP-stimulated platelets. In addition, fentanyl was found to interact with all the examined carrier proteins with dissociation constants in the order of 10–4 to 10–9 M.ConclusionsIt does not seem that the delayed platelet responsiveness to oral P2Y12 inhibitors, such as prasugrel, in patients undergoing percutaneous coronary intervention, results from direct interactions between fentanyl and blood platelets. Apolipoproteins, similarly to albumin and α1-acid glycoprotein, appear to be important carriers of fentanyl in blood.

Biomechanical activation of blood platelets via adhesion to von Willebrand factor studied with mesoscopic simulations.

Platelet adhesion and activation are essential initial processes of arterial and microvascular hemostasis, where high hydrodynamic forces from the bloodflow impede coagulation. The process relies on von Willebrand factor (VWF)-a linear multimeric protein of blood plasma plays a pivotal role in mechanochemical regulation of shear-induced platelet aggregation (SIPA). Adhesive interactions between VWF and glycoprotein receptors GPIb are crucial for platelet recruitment under high shear stress in fluid. Recent advances in experimental studies revealed that mechanical tension on the extracellular part of GPIb may trigger a cascade of biochemical reactions in platelets leading to activation of integrins [Formula: see text] (also known as GPIIb/IIIa) and strengthening of the adhesion. The present paper is aimed at investigation of this process by three-dimensional computer simulations of platelet adhesion to surface-grafted VWF multimers in pressure-driven flow of platelet-rich plasma. The simulations demonstrate that GPIb-mediated mechanotransduction is a feasible way of platelet activation and stabilization of platelet aggregates under high shear stress. Quantitative understanding of mechanochemical processes involved in SIPA would potentially promote the discovery of new anti-platelet medication and the development of multiscale numerical models of platelet thrombosis and hemostasis.

Enhanced Tumor Uptake and Retention of Cyanine Dye-Albumin Complex for Tumor-Targeted Imaging and Phototherapy.

Heptamethine cyanine dyes are widely used for in vivo near-infrared (NIR) fluorescence imaging and NIR laser-induced cancer phototherapy due to their good optical properties. Since most of heptamethine cyanine dyes available commercially are highly hydrophobic, they can usually be used for in vivo applications after formation of complexes with blood plasma proteins, especially serum albumin, to increase aqueous solubility. The complex formation between cyanine dyes and albumin improves the chemical stability and optical property of the hydrophobic cyanine dyes, which is the bottom of their practical use. In this study, the complexes between three different heptamethine cyanine dyes, namely clinically available indocyanine green (ICG), commercially available IR-786 and zwitterionic ZW800-Cl, and bovine serum albumin (BSA), were prepared to explore the effect of cyanine dyes on their tumor uptake and retention. Among the three complexes, IR-786©BSA exhibited increased tumor accumulation with prolonged tumor retention, compared to other complexes. Moreover, IR-786 bound to BSA played an important role in tumor growth suppression due to its cytotoxicity. To achieve complete tumor ablation, the tumor targeted by IR-786©BSA was further exposed to 808 nm laser irradiation for effective photothermal cancer treatment.

Fractional Composition of Protein in Blood Plasma of Carp (Cyprinus carpio) under the Aliphatic Amines

The effect of different concentrations of methylamine and propylamine in water on content and fractional composition of plasma proteins of the two-year-old carp (<i>Cyprinus carpio</i> L.) was studied. The total protein content in the blood plasma carp increased under methylamine concentration 0.009 mg/dm<sup>3</sup>, whereas its concentration 0.005 and 0.007 mg/dm<sup>3</sup> and all considered concentration of propylamine (0.04, 0.06 and 0.08 mg/dm<sup>3</sup>) did not affect total protein content. The main portion of proteins in the carp's blood plasma was formed by proteins of the molecular weight 52-54, 68-72 and 90 kDa, whereas content of proteins of the molecular weight 35, 80, 100, 150-170, 340 and 900 kDa was notably lower. After 72 h of exposition under different methylamine concentration, content of proteins of the molecular weight 25, 90 and 100 kDa increased, at the same time content of proteins of the molecular weight 35-52, 150-170 and 180-190 kDa decreased, and content of other proteins did not change. Changes of the proteins' fractional composition under the propylamine impact depended on its concentration and consisted in elevated content of proteins of the molecular weight 90 and 100 kDa, lower content of the fractions 150-170 and 180-190 kDa, and constant content of other fractions.

Хроническая сердечная недостаточность с сохраненной фракцией выброса на фоне предиабета и абдоминального ожирения: компартменты жировых депо и кардиометаболические маркеры

Aim: to assess the fat depot compartments and some cardiometabolic risk markers in patients with chronic heart failure with preserved ejection fraction (CHFpEF), prediabetes and abdominal obesity. Patients and Methods: this randomized open single-center study was carried out in the Research Institute for Therapy and Preventive Medicine — Branch of the Federal Research Center Institute of Cytology and Genetics of the Siberian Branch of the RAS and included 64 subjects (32 of them were males) with CHFpEF, prediabetes and abdominal obesity. The standard general clinical examination and laboratory tests, measurements of NT-proBNP and high-sensitivity C-reactive protein (CRP) in blood plasma, as well as ultrasonography for imaging epicardial and preperitoneal fat depots (lipometry) were used to evaluate patients. Results: median age of the studied male patients was 58.00 [54.25; 60.00] years, female patients — 58.00 [56.00; 59.00] years. Males had a higher body weight as compared to females (р=0.036). The level of NT-proBNP in women was lower than in men (p=0.036), just as the glomerular filtration rate (р=0.034). The thickness of the epicardial and preperitoneal fat layers were similar in men and women, while the subcutaneous fat layer was thicker in women (р=0.001). Male patients with grade 3 obesity had the lowest NT-proBNP concentration in blood plasma. In women with grade 2 and 3 obesity the concentration of high-sensitivity C-reactive protein (CRP) in blood plasma was higher than in women with overweight and grade 1 obesity (р=0.047). A moderate linear relationship between NT-proBNP and high-sensitivity CRP levels was found in female patients (r=0.375, p=0.034). Conclusion: body weight measurements, glomerular filtration rates and NT-proBNP concentrations in blood plasma were higher in the studied sample of men as compared to those in women. Male patients with grade 3 obesity had the minimal NT-proBNP level (just slightly above the diagnostic limit). The highest high-sensitivity CRP measurements were reported in women with grade 2 and 3 obesity which underscores their proinflammatory status. No significant differences in the visceral epicardial and preperitoneal fat compartments were found between male and female patients. KEYWORDS: chronic heart failure with preserved ejection fraction, prediabetes, obesity, NT-proBNP, C-reactive protein, epicardial fat, premesenteric fat, subcutaneous fat, males, females. FOR CITATION: Tsygankova O.V., Evdokimova N.E., Latyntseva L.D. Chronic heart failure with preserved ejection fraction amid prediabetes and abdominal obesity: fat depot compartments and cardiometabolic risk markers. Russian Medical Inquiry. 2023;7(1):22–29 (in Russ.). DOI: 10.32364/2587-6821-2023-7-1-22-29.

Offline Peptide Fractionation and Parallel Reaction Monitoring MS for the Quantitation of Low-Abundance Plasma Proteins.

Mass spectrometry (MS)-based protein quantitation is an attractive means for research and diagnostics due to its high specificity, precision, sensitivity, versatility, and the ability to develop multiplexed assays for the "absolute" quantitation of virtually any protein target. However, due to the large dynamic range of protein concentrations in blood, high abundance proteins in blood plasma hinder the detectability and quantification of lower-abundance proteins which are often relevant in the context of different diseases. Here we outline a streamlined method involving offline high-pH reversed-phase fractionation of human plasma samples followed by the quantitative analysis of specific fractions using nanoLC-parallel reaction monitoring (PRM) on a Q Exactive Plus mass spectrometer for peptide detection and quantitation with increased sensitivity. Because we use a set of synthetic peptide standards, we can more efficiently determine the precise retention times of the target peptides in the first-dimensional separation and specifically collect eluting fractions of interest for the subsequent targeted MS quantitation, making the analysis faster and easier. An eight-point standard curve was generated by serial dilution of a mixture of previously validated unlabeled ("light") synthetic peptides of interest at known concentrations. The corresponding heavy stable-isotope-labeled standard (SIS) analogues were used as normalizers to account for losses during sample processing and analysis. Using this method, we were able to improve the sensitivity of plasma protein quantitation by up to 50-fold compared to using nanoLC-PRM alone.

Absolute Quantitative Targeted Proteomics Assays for Plasma Proteins.

Preclinical and clinical trials require rapid, precise, and multiplexed analytical methods to characterize the complex samples and to allow high-throughput biomarker monitoring with low consumption of sample material. Targeted proteomics has been used to address these challenges when quantifying protein abundances in complex biological matrices. In many of these studies, blood plasma is collected either as the main research or diagnostic sample or in combination with other specimens. Mass spectrometry (MS)-based targeted proteomics using multiple reaction monitoring (MRM) or parallel reaction monitoring (PRM) with stable isotope-labeled internal standard (SIS) peptides allows robust characterization of blood plasma protein via absolute quantification. Compared to other commonly used technologies like enzyme-linked immunosorbent assay (ELISA), targeted proteomics is faster, more sensitive, and more cost-effective. Here we describe a protocol for the quantification of proteins in blood plasma using targeted MRM proteomics with heavy-labeled internal standards. The 270-protein panel allows rapid and robust absolute quantitative proteomic characterization of blood plasma in a 1h gradient. The method we describe here works for non-depleted plasma, which makes it simple and easy to implement. Moreover, the protocol works with the two most commonly used blood plasma collection methods used in practice, namely, either K2EDTA or sodium citrate as anticoagulants.

Роль связывания кортикостероидов с белками плазмы крови у облучённых животных в реализации эффектов радиопротекторов

The article presents a comparative analysis of radioprotectors RS-10 and RS-11 ability to enhance radioresistance in animals exposed to radiation that is based on results of research on protein-steroid interaction in acute radiation sickness. The importance of the research is caused by the need to conduct a comprehensive analysis of the mechanisms of radioprotective action of synthetic radioprotectors, including the revealing of the role of corticosteroid binding to blood plasma proteins in irradiated animals. The aim of the research was to investigate the impact of RS-10 and RS-11 radioprotectors on the binding of corticosteroids to blood plasma proteins in irradiated animals. 90 male Chinchilla rabbits weighing 2.5-3.0 kg were included in the experimental research. At the initial stage of the research the response of the adrenal cortex and the processes of their binding to blood plasma proteins after administration of RS-10 and RS-11 to intact animals was studied; at the next stage the same rates were used for the follow-up of the animals exposed to radiation after prophylactic administration of the radioprotectors. The rabbits were totally irradiated with gamma rays at a dose of 8 Gy that caused acute radiation sickness of the IV degree. The RS-10 (chitosan bitartrate) at the dose of 10.0 mg/kg and the RS-11 (similar to RS-10, but with a lower average molecular mass) at the dose of 2-7 mg/kg were intravenously injected to rabbits 15 minutes before the irradiation. Control animals were injected with an equal volume of the saline. The total content of 11-oxycorticosteroids (11-OCS) in the blood plasma was quantitated with the use of the fluorometric method in the author's modification. The amount of free corticosteroids was quantified as the difference between their content in the whole plasma and in its protein fraction after the gel-filtration chromatography with Sephadex G-25. The binding capacity of corticosteroid-binding globulin (CBG) was determined by gel filtration in the author's modification. The results of the study demonstrated the rise of the concentration of the blood plasma corticosteroids in the first hours after the RS-10 and RS-11 injection to intact animals, the amount of the free hormone increased as well. The effect of RS-10 on the rise of the free hormone levels was more pronounced as compared to the RS-11 effect. The impact of both radioprotectors on the elevation of the amount of 11-OCS binding to blood plasma proteins was similar. The introduction of RS-10 and RS-11 to the animals did not have effect on the binding capacity of the blood plasma proteins. The mechanism of radioprotective action of RS-10 and RS-11 in irradiated animals is the establishment of the optimal response of the adrenal cortex in the first hours after irradiation. The difference of the early adrenocortical response in animals irradiated and protected due to the injection of RS-10 and RS-11 from the optimal response varying towards strengthening or weakening, is the indicator of the radiation sickness severity. Prophylactic administration of RS-10 and RS-11 to irradiated animals at the height of the disease inhibited the reduction of the binding capacity of the CBG, resulting in the rise of the free hormone level at the higher total level of hormones in the blood is inhibited as well. In the mechanism for reducing post-radiation hypercorticism, with the use of the radioprotectors of RS-10 and RS-11, the main importance is the lower degree of the CBG binding capacity impairment rather than the change in the overall level of blood hormones. The higher prophylactic effect of RS-11 compared to RS-10 is confirmed by the significantly high rate of the binding ability of the CBG at the height of radiation sickness and the lower mortality among the animals involved in the experimental research.

Fabrication and development of a microfluidic paper-based immunosorbent assay platform (μPISA) for colorimetric detection of hepatitis C.

Paper-based microfluidics is an emerging analysis tool used in various applications, especially in point-of-care (PoC) diagnostic applications, due to its advantages over other types of microfluidic devices in terms of simplicity in both production and operation, cost-effectiveness, rapid response time, low sample consumption, biocompatibility, and ease of disposal. Recently, various techniques have been developed and utilized for the fabrication of paper-based microfluidics, such as photolithography, micro-embossing, wax and PDMS printing, etc. In this study, we offer a fabrication methodology for a microfluidic paper-based immunosorbent assay (μPISA) platform and the detection of Hepatitis C Virus (HCV) was carried out to validate this platform. A laser ablation technique was utilized to form hydrophobic barriers easily and rapidly, which was the major advantage of the developed fabrication methodology. The characterization of the μPISA platform was performed in terms of micro-channel properties using bright-field (BF) microscopy, and surface properties using scanning electron microscopy (SEM). At the same time, sample volume and liquid handling capacity were analyzed quantitatively. Ablation speed (S) and laser power (P) were optimized, and it was shown that one combination (10P60S) provided minimal deviation in micro-channel dimensions and prevented deterioration of hydrophobic barriers. Also, the minimum hydrophobic barrier width, which prevents cross-barrier bleeding, was determined to be 255.92 ± 10.01 μm. Furthermore, colorimetric HCV NS3 detection was implemented to optimize and validate the μPISA platform. Here, HCV NS3 in both PBS and human blood plasma was successfully detected by the naked eye at concentrations as low as 1 ng mL-1 and 10 ng mL-1, respectively. Moreover, the limit of detection (LoD) values for HCV NS3 were acquired as 0.796 ng mL-1 in PBS and 2.203 ng mL-1 in human blood plasma with a turnaround time of 90 min. In comparison with conventional ELISA, highly sensitive and rapid HCV NS3 detection was accomplished colorimetrically on the developed μPISA platform.

INTENSITY OF OXIDATIVE PROCESSES IN BLOOD AND LEVEL OF APOPTOSIS IN BLOOD LYMPHOCYTES IN RADIOLOGISTS/X-RAY TECHNOLOGIES EXPOSED TO SMALL DOSES OF IONIZING RADIATION.

to determine the presence of changes in peripheral blood parameters, characterizing its redox state, and the level of apoptosis of lymphocyte in radiologists/x-ray technologies who, due to their official duties, are exposed to small doses of ionizing radiation. The work was performed on blood samples of 45 professionals radiologists/x-ray technologies and 52 conventionally healthy individuals (control group). The content of malondialdehyde and sulfhydryl groups of proteins and peptides (-SH) in blood plasma was determined; catalase enzyme activity and the ratio of pro-antioxidant processes in hemolysates, the level of superoxide anion-radical (О2-) generation, the total production offree radical compounds (reactive forms of oxygen and nitrogen) and the level of apoptosis of peripheral blood lymphocytes (PBL). The content of malondialdehyde in the blood of professionals was increased by 1.49 times and the contentof -SH was decreased by 1.67 times compared to conventionally healthy individuals. An increase in the level of О2-production by 1.56 times was observed for PBL. The obtained results indicate a shift in the ratio between antioxidant and pro-oxidant processes towards the latter, which is confirmed by a 1.49-fold increase of this index. The levelfor PBL apoptosis was reduced by 1.35 times. For professionals, against the background of increased generation of О2-, a reliable direct correlation was observed between the indicator of apoptosis and the total production of free radical compounds, and between the latter and the level of apoptosis of lymphocytes, which was not noted for the conventionally healthy individuals group. A change in the ratio between pro- and antioxidant processes in the blood was found for professionals who are in contact with sources of ionizing radiation, which indicates the possibility of the development of oxidative stress, and the consequence of a reduced level of apoptosis of lymphocytes may be the danger of accumulating genetic damage in these cells.

The Blood Profile of Indonesian Native Chickens that Reared in Semi-Intensive System

The objective of the study was to evaluate the blood profile of Indonesian native chickens reared in a semi-intensive raised system. A total number of 68 chickens from four strains (Red Lurik, Wareng, Ranupane, and Putih) were used as samples. Chickens were challenged for 14 d in a semi-intensive raised system. Blood sampling was obtained from the pectoralis vein of the wing. The ANOVA and Duncant’s test were applied for data analysis. The observed variables consist of hemoglobin, erythrocytes, hematocrit, total blood plasma protein, leukocytes, and leukocyte differentiation. The results showed that chicken strains had a very significant difference (P < 0.01) in blood protein and hematocrit variables, a significant effect (P < 0.05) on hemoglobin levels, and no difference (P > 0.05) on the number of erythrocytes, leukocytes, and leukocyte. The highest hemoglobin level was found in the Ranupane strain (13.48 g dL-1). The highest blood protein and hematocrit values were found in the Putih strain at 7.60 g 100 mL-1 and 42.45 %, respectively. In conclusion that chicken strains of Lurik, Wareng, Ranupane, and Putih have different blood profiles (hemoglobin, blood protein, hematocrit, erythrocytes, leukocytes, and leukocyte differentiation). Consequently, the native chicken strain was normal even in a reared semi-intensive system.

Differences in Human Plasma Protein Interactions between Various Polymersomes and Stealth Liposomes as Observed by Fluorescence Correlation Spectroscopy.

A significant factor hindering the clinical translation of polymersomes as vesicular nanocarriers is the limited availability of comparative studies detailing their interaction with blood plasma proteins compared to liposomes. Here, polymersomes are self-assembled via film rehydration, solvent exchange, and polymerization-induced self-assembly using five different block copolymers. The hydrophilic blocks are composed of anti-fouling polymers, poly(ethylene glycol) (PEG) or poly(2-methyl-2-oxazoline) (PMOXA), and all the data is benchmarked to PEGylated "stealth" liposomes. High colloidal stability in human plasma (HP) is confirmed for all but two tested nanovesicles. In situ fluorescence correlation spectroscopy measurements are then performed after incubating unlabeled nanovesicles with fluorescently labeled HP or the specific labeled plasma proteins, human serum albumin, and clusterin (apolipoprotein J). The binding of HP to PMOXA-polymersomes could explain their relatively short circulation times found previously. In contrast, PEGylated liposomes also interact with HP but accumulate high levels of clusterin, providing them with their known prolonged circulation time. The absence of significant protein binding for most PEG-polymersomes indicates mechanistic differences in protein interactions and associated downstream effects, such as cell uptake and circulation time, compared to PEGylated liposomes. These are key observations for bringing polymersomes closer to clinical translation and highlighting the importance of such comparative studies.

Attomolar detection of hepatitis C virus core protein powered by molecular antenna-like effect in a graphene field-effect aptasensor

Biosensors based on graphene field-effect transistors have become a promising tool for detecting a broad range of analytes. However, their performance is substantially affected by the functionalization protocol. In this work, we use a controlled in-vacuum physical method for the covalent functionalization of graphene to construct ultrasensitive aptamer-based biosensors (aptasensors) able to detect hepatitis C virus core protein. These devices are highly specific and robust, achieving attomolar detection of the viral protein in human blood plasma. Such an improved sensitivity is rationalized by theoretical calculations showing that induced polarization at the graphene interface, caused by the proximity of covalently bound molecular probe, modulates the charge balance at the graphene/aptamer interface. This charge balance causes a net shift of the Dirac cone providing enhanced sensitivity for the attomolar detection of the target proteins. Such an unexpected effect paves the way for using this kind of graphene-based functionalized platforms for ultrasensitive and real-time diagnostics of different diseases.

Insight into synergetic effects of serum albumin and glucose on the biodegradation behavior of WE43 alloy in simulated body fluid

The biodegradation rate of Mg alloy medical devices, such as screws and plates for temporary bone fracture fixation or coronary angioplasty stents, is an increasingly important area of study. In vitro models of the corrosion behavior of these devices use revised simulated body fluid (m-SBF) based on a healthy individual’s blood chemistry. Therefore, model outputs have limited application to patients with altered blood plasma glucose or protein concentrations. This work studies the biodegradation behavior of Mg alloy WE43 in m-SBF modified with varying concentrations of glucose and bovine serum albumin (BSA) to (1) mimic a range of disease states and (2) determine the contributions of each biomolecule to corrosion. Measurements include the Mg ion release rate, electrolyte pH, the extent of hydrogen evolution (as a proxy for corrosion rate), surface morphology, and corrosion product composition and effects. BSA (0.1 g l–1) suppresses the rate of hydrogen evolution (about 30%) after 24 h and—to a lesser degree—Mg2+ release in both the presence and absence of glucose. This effect gets more pronounced with time, possibly due to BSA adsorption on the Mg surface. Electrochemical studies confirm that adding glucose (2 g l–1) to the solution containing BSA (0.1 g l–1) caused a decrease in corrosion resistance (by around 40%), and concomitant increase in the hydrogen evolution rate (from 10.32 to 11.04 mg cm–2 d–1) to levels far beyond the tolerance limits of live tissues.

Investigation of relationship between tau PET SUVR and an indicator of post‐translational modification of tau in human blood plasma using electrochemical assay

AbstractBackgroundHuman tau protein is a well‐known biomarker to predict and diagnose the progress of Alzheimer’s disease [1]. The tau protein undergoes various post‐translational modificiation (PTM) of tau such as phosphorylation, O‐glycosylation, nitration, and glycation. Recently, abnormal phosphorylation of tau protein is observed in AD patients, while the level of O‐GlcNAcylation on tau protein is relatively elevated in brains of normal controls [2]. Reference: [1] L.M. Ittner et al. Nature Reviews Neuroscience, 12 (2011) 67. [2] C. Alquezar et al. Frontiers in Neurology, 11 (2021) 595532:Method(Figure 1) To investigate tau protein in human blood plasma and its PTM, a novel type of electrochemical sensor demonstrated and obtained Taumeter, an indicator as relative impedance changes of phosphorylated tau and O‐glycosylated tau, using secondary antibodies Finally, the as‐obtained Taumeter and PET SUVR were investigated for a relationship.ResultWe investigated the clinical relationship between Taumeters for AT8 and AT270 and tau PET SUVR, respectively, obtained from human blood plasma from normal control (NC, n=9), mild cognitive impairment (MCI, n=14), and Alzheimer’s disease (AD, n=13). In the case of AT8, it was observed that average Taumeters in MCI and AD were 2.86 and 4.73 times higher than those in NC (p=0.078 between NC and AD) (Figure 2a). In the case of AT270, average Taumeters in MCI and AD were 1.84 and 4.24 times higher than those in NC (p=0.057 between NC and AD) (Figure 2b). In further study, Taumeters for AT8 and AT270 correlated with tau PET SUVR (r=0.151, p=0.384 and r=0.575, p<0.001) (Figure 2c‐d).ConclusionIn this study, we investigated Taumeter reflecting PTM of tau proteins using secondary antibodies (O‐GlcNAc antibody, AT8, and AT270) in human blood and tau PET scan to investigate the relationship of Taumeter and tau PET SUVR in NC, MCI, and AD. As a result, it can be carefully implied that Taumeter has the relationship with the progress of AD.

Analysis of the level of oxidative stress by assessing the damage to the plasma protein serum albumin under the influence of an oxidizing agent

Oxidative stress, which leads to oxidative modification of various macromolecules, including proteins, is now considered an important pathogenetic link in many diseases. In this work, oxidative damage to a blood plasma protein, bovine serum albumin BSA, under the action of an oxidizing agent, hydrogen peroxide H2O2, was studied by spectrofluorometric method. The H2O2 concentration-dependent quenching of the intrinsic fluorescence of BSA is shown. BSA fluorescence quenching constants in hydrogen peroxide solutions are calculated by mathematical modeling methods. The dependences found in the fluorescence quenching constants are explained both by oxidative damage to the microenvironment of BSA tryptophan residues and by changes in the native conformation of protein globules upon oxidative damage. More significant peroxide damage to BSA occurs at lower pH values due to the fact that H2O2, as an oxidizing agent, acts more strongly in an acidic environment. The registered quenching of the protein's own fluorescence when damaged by an oxidizing agent can be used as a medical method for assessing the level of oxidative stress in the body in the diagnosis of a number of diseases.

Silk fibroin and recombinant elastin blend nano-coatings for implantable medical devices

Silicone breast implants are conventionally used to reconstruct the shape and size of the breast in breast cancer patients. However, rate of failure of implants due to formation of capsular contracture is significantly high. Recent studies have shown that coating the surface of the implant with a biocompatible polymer can mitigate this risk. Here, we have modified the surface of implant using a biocompatible natural biopolymer silk fibroin (SF). Further, we have developed formulations of SF with a recombinantly produced elastin-like-peptide (ELP) and compared their performance with a known anti-fouling hydrophilic polymer - polyethylene oxide (PEO). Microscopic and spectroscopic characterization confirm the formation of uniform coatings. These coatings have been also characterized for their ability to resists crack formation. Further, the coatings have been evaluated for their biological performance. Our studies show that addition of 25 wt% of ELP to SF significantly enhances the crack resistance for the coatings. In addition, SF/ELP coatings reduce the adsorption of blood plasma proteins by more than 80%. Preliminary analysis shows that the SF/ELP blend coatings are non-cytotoxic and support adhesion, growth and proliferation of fibroblast cells. The study therefore demonstrates that SF/ELP coatings have the potential to mitigate the risk of breast implant failure.