Gel Separation Research Articles

Insight into peroxidase-mediated Morinda citrifolia L. (noni) fruit juice browning and precipitation and a thermal inactivation strategy.

Peroxidase-mediated enzymatic browning during the process of noni fruit juice causes major color deterioration and precipitation, which negatively affects consumer acceptance of the juice. The purpose of this study was to understand the browning and precipitate formation mechanisms in noni fruit juice and improve its quality. Peroxidase was isolated from noni fruit via gel separation purification and characterized for its kinetic properties. The influences of key phenolic compounds on browning and precipitate formation were investigated via a noni-juice-based model system. The results revealed that the major noni peroxidase was a 50.05 kDa dimer subunit, and peroxidase activity was optimal at pH 6.0 and 30 °C, with an activation energy of 159.50 kJ/mol. Additionally, peroxidase activity was significantly inhibited by glutathione, sodium metabisulfite, and ascorbic acid. The active sites contained histidine and arginine residues. All eight phenolic compounds in juice act as specific substrates for peroxidase-mediated browning. Among them, gallic acid made the most significant contribution to both browning and precipitate formation. To effectively deactivate peroxidase activity while minimizing phenolic compound loss, a thermal treatment of 90 °C for 10 min was identified as the optimal approach. This study provides new insights into improving the quality of noni juice and enzyme browning.

Identification of umami peptides and mechanism of the interaction with umami receptors T1R1/T1R3 in pigeon meat.

Pigeon meat offer an ideal source for extracting fresh flavor peptides. These peptides not only enhance the taste of food but also have potential health benefits, including providing low-sugar, low-sodium, and low-calorie options for individuals with conditions like diabetes, hypertension, and obesity. Therefore, further research into the pigeon industry holds promise for addressing both economic and nutritional needs. To explore umami peptides and their molecular binding mechanisms with umami receptor type 1 member 1 in pigeon meat, an enzymatic hydrolysate product is isolated, analyzed, and subjected to sensory evaluation. Fifteen peptides with high freshness characteristics are separated and identified by ultrafiltration, gel separation, reverse performance liquid chromatography, and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS). The molecular docking results show that the amino acid residue Glu128 is a common ligand binding site for all of the fresh-flavored peptides to taste T1R1/T1R3 receptors and it exerts freshness-presenting effects with 15 fresh-flavored peptides through hydrogen bonding, electrostatic interactions, salt bridges, and hydrophobic interactions. This study provides a theoretical basis and technical support for the subsequent development of flavor peptide products in pigeon meat.

Retracted] Zearalenone regulates endometrial stromal cell apoptosis and migration via the promotion of mitochondrial fission by activation of the JNK/Drp1 pathway.

Following the publication of this article, a concerned reader drew to the Editor's attention that the experimental design of the western blot assay experiments portrayed in Fig. 5A on p. 7804, and the overall organization of this figure, may have been flawed, as mitochondrial and cytosolic proteins were featured in the figure with only one set of supporting control western blot data; in this scenario, the proteins would necessarily have needed to have been obtained from two separate cell samples in different experiments, and blotted on to separate gels. Moreover, there was also a concern that certain of the gels featured possible breaks in their continuity/splicing events, such that the protein bands in the figure were not shown consecutively, as they would have appeared, in the affected slices. After having conducted an internal investigation, the Editor of Molecular Medicine Reports agrees with the reader that there were anomalies associated with the presentation of Fig. 5. Therefore, on the grounds of a lack of confidence in the presented data, the Editor has decided that the article should be retracted from the publication. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused, and we also thank the reader for bringing this matter to our attention. [Molecular Medicine Reports 17: 7797‑7806, 2018; DOI: 10.3892/mmr.2018.8823].

A-163 Stability of apixaban in Li-heparin plasma stored refrigerated over mint green-top tube separator gel

Abstract Background Apixaban is a factor Xa inhibitor used as a direct oral anticoagulant (DOAC). The laboratory was asked to provide measurements of plasma apixaban in the context of studies regarding interaction of apixaban with other therapeutic drugs. One study involved isolation of plasma from to-be-discarded specimens, where such specimens were those originally collected in mint green-top tubes (Li-heparin tubes containing plasma separator gel), and that had been centrifuged and stored refrigerated for 5 days. Whereas apixaban concentration is known to be stable in refrigerated plasma specimens for up to two weeks, stability of apixaban concentration in plasma stored refrigerated for prolonged periods over plasma separator gel was unknown. Our objective was to examine stability of apixaban in plasma stored refrigerated for 5 days over plasma separator gel. Methods Pharmacy records were reviewed to identify inpatients who were prescribed apixaban, and for whom a mint green-top tube specimen (Becton-Dickinson BD Vacutainer PST Gel and Lithium Heparin, #367961) had been drawn for routine chemistry tests. From such specimens, 500 uL aliquots of plasma were obtained on day 1 (A) and day 5 (B) of storage under refrigeration (4 °C). Apixaban concentrations for A and B were measured by LC-MS/MS and compared. Additionally, short term (1 day) stability of apixaban was examined by comparison of replicate measurements of apixaban in a single spiked pooled purple-top plasma specimen (Becton-Dickinson BD Vacutainer K2 EDTA, #367856), with (C) or without (D) exposure to mint green-top tube separator gel for a 24h refrigeration period. Data analyses were conducted using R (version 4.0.5). Results A total of 21 specimen pairs (A, B) were examined. [Apixaban] ranged from 30-1000 ng/mL. The ratio B/A was 1.007 ± 0.034, consistent with no effect on plasma [apixaban] of refrigerated storage over separator gel between day 1 and day 5 (by paired t-test: p>0.8). Experiments for replicates of (C, D) specimens (n = 4, average [apixaban] = 410 ng/mL) gave D/C ratio of 1.009 ± 0.019, consistent with no effect on plasma [apixaban] of short term (1 day) refrigerated storage of plasma over separator gel (by paired t-test: p>0.4). Conclusions For plasma specimens collected and centrifuged in mint-green plasma separator tubes, there was no effect on plasma [apixaban] of refrigerated storage over separator gel for periods of 0-5 days.

A-060 Assessing Glucose Stability: A Comparison of Citrate/NaF, NaF, and Gel Separator Vacuum Tubes in Routine Medical Laboratory Practice

Abstract Background In cases where a glycolysis inhibitor is not utilized, blood cells in vitro can consume glucose. Although current guidelines suggest using citrate-buffered inhibitors or ice-water slurry to mitigate this, practical and financial constraints often hinder adherence to these recommendations. Our objective was to evaluate the difference in glucose concentration in our routine sample management by employing Citrate buffered/NaF, NaF, and Gel Barrier tubes. Methods In this study, we utilized Greiner FCmix citrate-buffered NaF and EDTA tubes (3 mL), Becton Dickinson NaF and EDTA tubes (4 mL), and Becton Dickinson SSTII Gel Barrier tubes (5 mL). Following venipuncture, the tubes were transferred to the laboratory and centrifuged within 30 minutes. Glucose levels of 46 patients' samples were measured using a Cobas 6000 system (c501) employing the Glucose Hexokinase method, which exhibits an intermediate coefficient of variation (CV) of approximately 1.5% and no significant bias, as confirmed by monitoring with Biorad EQAS. Results The mean plasma glucose difference between Citrate-buffered tubes and NaF tube samples was 2.8 mg/dL with a 95% confidence interval (CI) ranging from 2.2 to 3.4 mg/dL (Mean: 0.16 mmol/L; CI: 0.12 - 0.19 mmol/L). The difference in paired samples of NaF plasma and Gel Barrier tubes serum glucose was 3.2 mg/dL with a CI of 2.5 - 3.9 mg/dL (Mean: 0.18 mmol/L; CI: 0.14 - 0.22 mmol/L). Lastly, the mean difference in Citrate-buffered plasma and serum Gel barrier tubes for 46 paired samples was 6.0 mg/dL with a CI of 5.2 - 6.7 mg/dL (Mean: 0.33 mmol/L; CI: 0.29 - 0.37 mmol/L). Conclusions Following guidelines, Citrate-buffered/NaF tubes demonstrate efficacy as glucose stabilizers. When compared to NaF tubes alone within a 30-minute timeframe, the mean difference between the two types of tubes was 2.8 mg/dL. Although NaF tubes are no longer recommended for glucose testing in plasma, they still outperform gel barrier serum tubes by 3.2 mg/dL. Furthermore, compared to citrate/NaF Plasma, serum glucose levels were on average 6.0 mg/dL lower. The preanalytical sample stage poses a significant obstacle to its reliable use for diagnostic or monitoring purposes. Laboratories should consider transitioning to Citrate/NaF tubes, or employ mathematical corrections if utilizing gel separator tubes for glucose testing in their established preanalytical process.

A-056 Investigating Iodine Contrast Contamination in Cortisol and Aldosterone Samples

Abstract Background Primary aldosteronism (PA) is a condition characterized by hypertension resulting from excess secretion of aldosterone. PA caused by a unilateral aldosterone-producing adenoma can be treated with adrenalectomy but requires diagnosis by adrenal vein sampling (AVS). In this procedure, intravenous cosyntropin is administered to stimulate adrenal cortical secretion, followed by obtaining samples from the right and left adrenal veins and IVC. Laterization index is calculated by obtaining the aldosterone:cortisol ratio for each side, with a ratio cutoff ≥3 is used for confirmation. Iodinated contrast media facilitates visualization of catheter positioning during AVS and sometimes results in contamination of samples, evidenced by abnormal gel separator flotation (i.e. gel above plasma). This study had two aims: 1) to determine at what concentration contrast dye causes gel flotation and 2) discern whether contrast media interferes with our cortisol or aldosterone assays. Methods Gel flotation studies were performed by spiking pooled plasma samples with iohexol contrast media (Omnipaque 240, GE Healthcare) at concentrations ranging from 3%-10% v/v and aliquoting into fresh lithium heparin plasma separator tubes (BD, PSTs). Samples were then centrifuged and visually inspected for abnormal gel flotation. Contrast interference studies were performed using three pools of low (5 µg/dL), medium, (30 µg/dL), and high (55 µg/dL) cortisol concentrations. Sample pools were diluted with 20% contrast media or saline (control) and subsequently mixed at different ratios to create a range of dye concentrations (0.5%-18% v/v). Each mixture was assayed in triplicate for cortisol and aldosterone on a cobas e602 (Roche Diagnostics) and LIAISON XL (DiaSorin) immunoanalyzer, respectively. The total allowable error (TEa) was ±0.4 μg/dL or ±20% for cortisol and ±2 ng/dL or ±20% for aldosterone. Results Flotation of the gel separator was observed at a dye concentration of 4.5% v/v and greater. For the cortisol interference study, the bias was <5% for the three pools at all contrast media concentrations. Aldosterone was also measured in these pools, as bias could affect ratios calculated for PA. Aldosterone interference occurred at contrast dye concentrations ranging from 12%-20% v/v. An average positive bias of 34% was observed in aldosterone samples spiked with contrast media relative to the saline control. Compared to sample pool controls without added saline or dye, measurements for cortisol and aldosterone were 19%-22% and 16-25% lower in media- and saline-spiked samples (20% v/v), respectively, indicating a logical dilution effect. Conclusions Contrast dye contamination of AVS specimens can cause gel flotation in lithium heparin PSTs, preventing their analysis. The presence of contrast media at certain concentrations interfered with the DiaSorin aldosterone assay, leading to falsely elevated results. No cortisol assay interference occurred in the presence of contrast media but results were falsely decreased due to sample dilution. Samples collected during AVS may be contaminated with contrast dye causing gel flotation to occur. This is indicative of a minimum contrast media concentration of 4.5% v/v. Aldosterone:cortisol ratios may be inaccurate due to the positive aldosterone immunoassay bias with contrast media contamination. Care should be taken when reporting and interpreting AVS results with suspected contamination.

Critical Insights on Preparation of Platelet-Rich Plasma in Tubes With a Thixotropic Gel Separator.

Thixotropic gels are the preferred choice in the collection of platelet-rich plasma as an easy solution to operator variability. One often unnoticed shortcoming is the entrapment of platelets in the gel layer's uppermost surface. We provide instructions to optimize platelet yield, ie, agitation to re-suspend platelets, setting the optimal G-force and time of centrifugation, and the essential use of a horizontal swing bucket centrifuge. We conclude that this technique represents a new clinical and research direction, particularly to optimize platelet counts. We therefore encourage others to utilize this technique in future endeavors. J Drugs Dermatol. 2024;23(11):979-985. doi:10.36849/JDD.7983.

Use of Near-to-Microporous Silica Gel for Selective Separation of Petroleum Vanadyl Porphyrins from Asphaltene Clusters

Use of Near-to-Microporous Silica Gel for Selective Separation of Petroleum Vanadyl Porphyrins from Asphaltene Clusters

Platelet-Rich Plasma (PRP) Based on Simple and Efficient Integrated Preparation Precises Quantitatively for Skin Wound Repair.

Platelet-rich plasma (PRP) has become an important regenerative therapy. However, the preparation method of PRP has not been standardized, and the optimal platelet concentration for PRP used in skin wound repair is unclear, leading to inconsistent clinical efficacy of PRP. Therefore, the development of standardized preparation methods for PRP and the investigation of the dose-response relationship between PRP with different platelet concentrations and tissue regeneration plays an important role in the development and clinical application of PRP technology. This study has developed an integrated blood collection device from blood drawing to centrifugation. Response surface methodology was employed to optimize the preparation conditions, ultimately achieving a platelet recovery rate as high as 95.74% for PRP (with optimal parameters: centrifugation force 1730× g, centrifugation time 10 min, and serum separation gel dosage 1.4 g). Both in vitro and in vivo experimental results indicate that PRP with a (2×) enrichment ratio is the most effective in promoting fibroblast proliferation and skin wound healing, with a cell proliferation rate of over 150% and a wound healing rate of 78% on day 7.

A false reactive hepatitis B surface antigen result due to dislodged gel from Vacutainer

Abstract: Preanalytical variables play a key role in the correctness of laboratory test results. We report a false reactive result for hepatitis B surface antigen (HBsAg) on serological testing with a relatively low OD. The pilot sample was collected in yellow top BD Vacutainer® (SST™ II Advance 5 mL tube) with separator gel and was marked for serological testing. It was centrifuged at 7000 rpm for 30 min. Serological testing was performed by chemiluminescence on Abbott Architect Plus i1000SR with Abbott kits for HBsAg, anti-HIV, and anti-HCV. This particular sample tested reactive for HBsAg with S/CO of 1.91, S/CO for HBsAgQ2NC (Negative kit control) being 0.19 and that of HBsAgQ2PC (Positive kit control) being 3.65. Repeat testing from the same Vacutainer was also reactive for HBsAg with S/CO of 2.10. Nucleic acid testing was performed and was found to be nonreactive. We repeated serological testing with a sample from fresh frozen plasma of the same donor unit. It was nonreactive. Cross contamination was ruled out by repeat testing of two serial samples before and after this unit number. The serum showed an unusual appearance on visual inspection after centrifugation. By exclusion, we concluded that the gel probably got partially dislodged into the serum, giving a relatively low reading and false reactive result for HBsAg. This highlights the possibility of inert gel not always being inert, the importance of repeat testing from a different sample in case of low reading, the importance of visual inspection, a need for manufacturers and laboratory personnel to consider such preanalytical variables which, though not much mentioned in literature, can affect test results. These results have a multi-fold impact on the donor or patient’s mindset, treatment outcome and/or fate of blood donation. These are definitely preventable if more such guidelines are made available for handy reference in handling such results.

A flexible solid-state asymmetric supercapacitor device comprising cobalt hydroxide and biomass-derived porous carbon.

Development in the field of alternative and renewable energy sources is becoming necessary considering the current energy demands of the growing technologies. The main challenge associated with the produced energy is to store it for future use, such that it can be used when needed. Supercapacitors are among the electrochemical energy storage systems that provides higher power density, faster charging-discharging, high specific capacitance (C S), and long cycling life. Herein, the fabrication of a flexible solid-state asymmetric supercapacitor (ASC) device is reported, where Co(OH)2 hollow spheres and biomass-derived porous carbon (PC) are the cathode and anode, respectively. Co(OH)2 is a highly redox active material, whereas PC is an electric double-layer capacitive (EDLC) material. In this device, aqueous KOH solution (electrolyte) encapsulated in PVA gel (separator) was used to bind the electrodes. This Co(OH)2//PC ASC device exhibited a high C S of 260 F g-1 (at 2 A g-1). It retained ∼91% of the initial C S value (at 6 A g-1) till ∼5000 cycles. Electrochemical impedance spectroscopy (EIS) study confirmed low internal resistance (0.95 Ω) and charge transfer resistance (1.41 Ω) values of Co(OH)2//PC. These results indicate that the high electron transfer process in the electrode-electrolyte interface during the electrochemical reaction, which is responsible for the excellent performance of this ASC device. The high-performance Co(OH)2//PC ASC device exhibited an energy density of 76.7 W h kg-1 at a power density of 1416.9 W kg-1. To demonstrate its practical use, LED lights were illuminated using this Co(OH)2//PC ASC device.

Effect of freezing on physicochemical properties and microstructure of soy protein gels

This study aimed to analyze the dynamic evolution of physicochemical properties and microstructure in soybean protein gels subjected to freezing conditions. SPI, 7S, and 11S were used in experiments. A 12g/100g protein gel was formulated after 1 and 5 days of freezing. Subsequent determination and analysis encompassed various indices, including texture, subunit composition, sulfhydryl group content, water distribution, and microstructure. The findings revealed a significant increase in the hardness of SPI, 7S, and 11S protein gels with prolonged freezing time. The 11S gel exhibited the most substantial increase, followed by SPI and 7S. And the decreases in the water-holding properties of the protein gels were 10.08%, 1.19%, and 49.34%, with the largest decrease in the water-holding properties of the 11S protein gels. Conversely, the water-holding capacity and total sulfhydryl content of SPI, 7S, and 11S protein gels decreased over time during freezing. Subunit distribution analysis indicated darker bands at the top of concentrated and separation gels. The freezing process induced the formation and growth of ice crystals, altering the spatial network structure of protein gels. Consequently, the proportion of free water in all three soybean protein gels increased, leading to enhanced mobility and a looser network structure.

Evaluation of fluorous affinity using fluoroalkyl-modified silica gel and selective separation of poly-fluoroalkyl substances in organic solvents.

In this study, we focused on the fluorous affinity acting among fluorine compounds, and then developed a new separation medium and evaluated their performance. We prepared the stationary phases for a column using silica gel-modified alkyl fluoride and investigated the characteristics of fluorous affinity by comparing them with a typical stationary phase, which does not contain fluorine, using high-performance liquid chromatography (HPLC). In HPLC measurements, we confirmed that while all non-fluorine compounds were not retained, retention of fluorine compounds increased as the number of fluorine increased with the stationary phase. It also revealed that the strength of fluorous affinity changes depending on the types of the organic solvent; the more polar the solvent, the stronger the effect. Additionally, the stationary phase was employed to compare the efficiency of our column with that of a commercially available column, Fluofix-II. The retention selectivity was almost the same, but the absolute retention strength was slightly higher on our column, indicating that the column is available for practical use.

A new assay falsely increases lactate dehydrogenase in plasma but not in serum

IntroductionSerum is the International Federation of Clinical Chemistry (IFCC)-recommended matrix for the measurement of lactate dehydrogenase (LD); however, many laboratories opt for lithium heparin plasma to achieve quicker turnaround times and minimize tube usage.When introducing the new Sigma-Strong IFCC-recommended LDH2 assay from Abbott Laboratories on lithium-heparin collected samples, we observed a rise in the patient median LD activity as well as several samples exhibiting falsely elevated values. Materials and methods120 + serum and plasma samples from consenting patients were collected and evaluated for complete blood count and lactate dehydrogenase using two different assays. Aggregated patient results before and after introduction of the LDH2 assay were compared. ResultsMean LD was 14% higher in plasma than in serum when using the LDH2 assay but only 5% higher when using the previous LDH legacy assay from Abbott Laboratories. Similarly, platelets and leukocytes were 10–30 times higher in plasma than in serum. Aggregated lactate dehydrogenase patient results demonstrated a dramatic increase in patient median following introduction of the LDH2 assay. Various experiments were tried to reduce cellular interference, but the only viable solution we found, apart from reverting to the LDH legacy assay, was to utilize serum tubes. ConclusionWe conclude that lithium-heparin plasma leads to falsely elevated lactate dehydrogenase activity when using the LDH2 assay. These errors can be prevented by using serum collected in gel separator tubes.

Native Mass Spectrometry-Centric Approaches Revealed That Neuropeptides Frequently Interact with Amyloid-β.

Amyloid-β (Aβ) aggregates are recognized as initiators of Alzheimer's disease, and their interaction with the nervous system contributes to the progression of neurodegeneration. Herein, we investigated the frequency at which neuropeptides interact with Aβ and affect the aggregation kinetics and cytotoxicity of Aβ. To this end, we established a native mass spectrometry (MS)-centric workflow for screening Aβ-interacting neuropeptides, and six out of 12 neuropeptides formed noncovalent complexes with Aβ species in the MS gas phase. Thioflavin-T fluorescence assays and gel separation indicated that leptin and cerebellin decreased Aβ aggregation, whereas kisspeptin increased this process. In addition, leptin and cerebellin attenuated Aβ-induced cytotoxicity, which was independent of the influence of metal ions. Leptin can chelate copper from copper-bound Aβ species, reducing the cytotoxicity caused by the aggregation of Aβ and metal ion complexes. Overall, our study demonstrated that neuropeptides frequently interact with Aβ and revealed that leptin and cerebellin are potential inhibitors of Aβ aggregation, providing great insight into understanding the molecular mechanism of Aβ interacting with the nervous system and facilitating drug development.

Differences in Eotaxin Serum Levels between Polytraumatized Patients with and without Concomitant Traumatic Brain Injury-A Matched Pair Analysis.

Background/Objectives: Early detection of traumatic brain injury (TBI) is crucial for minimizing secondary neurological damage. Our study aimed to assess the potential of IL-4, IL-6, IL-7, IL-8, IL-10, TNF, and eotaxin serum levels-as a single clinical tool or combined into a panel-for diagnosing TBI in multiple injured patients. Methods: Out of 110 prospectively enrolled polytrauma victims (median age, 39 years; median ISS, 33; 70.9% male) admitted to our level I trauma center over four years, we matched 41 individuals with concomitant TBI (TBI cohort) to 41 individuals without TBI (non-TBI cohort) based on age, gender, Injury Severity Score (ISS), and mortality. Patients' protein levels were measured upon admission (day 0) and on days 1, 3, 5, 7, and 10 during routine blood withdrawal using one separation gel tube each time. Results: The median serum levels of IL-4, IL-6, IL-7, IL-8, IL-10, and TNF exhibited non-similar time courses in the two cohorts and showed no significant differences on days 0, 1, 3, 5, and 7. However, the median eotaxin levels had similar trend lines in both cohorts, with consistently higher levels in the TBI cohort, reaching significance on days 0, 3, and 5. In both cohorts, the median eotaxin level significantly decreased from day 0 to day 1, then significantly increased until day 10. We also found a significant positive association between day 0 eotaxin serum levels and the presence of TBI, indicating that for every 20 pg/mL increase in eotaxin level, the odds of a prevalent TBI rose by 10.5%. ROC analysis provided a cutoff value of 154 pg/mL for the diagnostic test (sensitivity, 0.707; specificity, 0.683; AUC = 0.718). Conclusions: Our findings identified the brain as a significant source, solely of eotaxin release in humans who have suffered a TBI. Nevertheless, the eotaxin serum level assessed upon admission has limited diagnostic value. IL-4, IL-6, IL-7, IL-8, IL-10, and TNF do not indicate TBI in polytraumatized patients.

The Advances in Phospholipids-Based Phase Separation Gels for the Sustained Release of Peptides, Proteins, and Chemotherapeutics.

Implantable drug delivery systems formed upon injection offer a host of advantages, including localized drug administration, sustained release, minimized side effects, and enhanced patient compliance. Among the various techniques utilized for the development of in situ forming drug implants, solvent-induced phase inversion emerges as a particularly promising approach. However, synthetic polymer-based implants have been associated with undesirable effects arising from polymer degradation. In response to this challenge, a novel category of drug delivery systems, known as phospholipids-based phase separation gels (PPSGs), has emerged. These gels, characterized by their low initial viscosity, exhibit injectability and undergo rapid transformation into in situ implants when exposed to an aqueous environment. A typical PPSG formulation comprises biodegradable components, such as phospholipids, pharmaceutical oil, and a minimal amount of ethanol. The minimized organic solvents in the composition show good biocompatibility. And the relatively simple composition holds promise for industrial-scale manufacturing. This comprehensive review provides an overview of the principles and advancements in PPSG systems, with specific emphasis on their suitability as drug delivery systems for a wide range of active pharmaceutical ingredients (APIs), spanning from small molecules to peptides and proteins. Additionally, we explore the critical parameters and underlying principles governing the formulation of PPSG-based drug delivery strategies, offering valuable insights on optimization strategies.

Analysis of Dimethylsiloxanes in Hydrocarbon Matrices like Marine Fuels Applying a Novel Enrichment Procedure and a Two-Column Gas Chromatography – Mass Spectrometry Measurement

Marine fuels are consumed worldwide in quantities of more than 200 million tons per year. It is not a uniform product, but rather heterogeneous mixtures of hydrocarbons with a wide range of viscosities. Due to the production processes, marine diesel contains dimethylsiloxanes. These lead to damage to marine exhaust catalysts in connection with combustion reactions in the ships’ engines. A novel analytical method, presented here, was developed that allows to investigate these processes and to monitor the dimethylsiloxane contents in complex marine fuel matrices. The key steps of the analytical procedure are analyte enrichment by solid phase extraction (SPE) using thermally activated silica gel and chromatographic separation and measurement by heart-cutting gas chromatography - mass spectrometry. Authentic reference substances for quantification by standard addition are used for the dimethylsiloxane analytes. The clean-up enabled a 90% reduction of the matrix content in the analysis solutions compared to the initial sample. Recovery rates in the range of 87.8% to 111.4% were determined for all analytes (Si3 to Si9). The detection limits of analytes ranged from 0.06 μg/L to 5.68 μg/L. Values of 0.71 μg/L to 23.6 μg/L were determined for the limits of quantification. The newly designed analytical method was successfully applied to real marine fuel samples. The analytical procedure is to be made available to commercial and industrial laboratories as a practical method for controlling siloxane contents in marine fuels to contribute this way to efficiently functioning marine exhaust gas purification.

A MOF-Gel Based Separator for Suppressing Redox Mediator Shuttling in Li-O2 Batteries.

Redox mediators (RMs) are widely utilized in the electrolytes of Li-O2 batteries to catalyze the formation/decomposition of Li2O2, which significantly enhances the cycling performance and reduces the charge overpotential. However, RMs have a shuttle effect by migrating to the Li anode side and inducing Li metal degradation through a parasitic reaction. Herein, a metal-organic framework gel (MOF-gel) separator is proposed to restrain the shuttling of RMs. Compared to traditional MOF nanoparticles, MOF gels form uniform and dense films on the separators. When using Ru(acac)3 (ruthenium acetylacetonate) as an RM, the MOF-gel separator suppresses the shuttling of Ru(acac)3 toward the Li anode side and significantly enhances the performance of Li-O2 batteries. Specifically, Li-O2 batteries exhibit an ultralong cycling life (410 cycles) at a current density of 0.5 A g-1. Moreover, the batteries using the MOF-gel/celgard separator exhibit significantly improved cycling performance (increase by ≈1.6 times) at a high current density of 1.0 A g-1 and a decreased charge/discharge overpotential. This result is expected to guide future development of battery separators and the exploration of redox mediators.

#749 Components in blood collection tubes interfere with the spectral signatures of patients with kidney disease: analysis by infrared microspectroscopy

Abstract Background and Aims Kidney disease is a worldwide public health problem, affecting between 8%-16% of the global population. Chronic Kidney Disease (CKD) is a silent disease and its detection is often late, making the treatment difficult. Considering the emerging Fourier-Transform Infrared spectroscopy (FTIR) as a biophotonic resource for the biomedical sciences, we aimed to identify spectral signatures related to biomarkers of CKD in human blood serum using the microscopy FTIR option. Method Blood serum samples from 17 healthy in comparison to 33 CKD patients were analyzed by micro-reflectance FTIR spectroscopy. The first aspect to be addressed refers to the possible influence of components present in the container tube. Here we showed that separator gel in VACUETTE® tubes is a relevant source of spectral interference which could decrease the accuracy of discrimination from 85% to 65%. Acquiring a diluted gel signal as a background would improve the discrimination performance in spite of some gel bands still present in sample data. Results In this case, our results indicated that vibrations associated with galactose-4-sulfate, CH2 bending of the methylene chains, C=C in lipids and fatty acids, C=N stretching, CH bending vibration from the phenyl rings, N-H bending vibration coupled to C-N stretching and β-sheet of Amide II and ring base are modulated in blood serum samples of chronic kidney disease patients compared to healthy patients. Urinary trypsin inhibitors, fatty acids, phenolic derivatives, tryptophan, and plasminogen were the biomolecules related to these assignments were the biomolecules related to these assignments. Conclusion In conclusion, FTIR is a viable option for fast diagnosis of chronic kidney disease being also a powerful tool for monitoring the disease. Due to its capability of large batch analysis, the micro-FTIR would be an eligible technology for clinical laboratories in healthcare facilities. However, for direct clinical applications, ATR-FTIR would be the option of choice.