Standard Liquid Research Articles

Strange sounds

This latter addresses the effects of long-ranged and/or retarded interactions on the bosonic collective modes in the so-called ‘strange metals’. Recently, there have been conflicting reports on the very existence of such stable collective excitations and their properties. Extending a number of approaches that have been previously used in the analyses of the standard Fermi liquid one finds evidence for, both, conventional and novel behaviors of the non-Fermi-liquid counterparts of the zero-, shear-, and other ‘sounds’.

Assessment of diagnostic accuracy of Gazelle: A point-of-care testing device for screening β-thalassemia trait.

Background & objectives Timely detection of population with β-thalassemia trait (BTT) followed by genetic counselling is an advocated method of preventing the birth of a child with β-thalassemia major. In this study we aim to assess the diagnostic accuracy of Gazelle, a point-of-care (POC) testing device, in screening for BTT in hospital laboratory setting. Methods Standards for Reporting Diagnostic Accuracy (STARD) guidelines were followed in developing study design, recruiting study participants and sample size calculation for the current research. A consecutive sample of 446 participants was recruited for this study and was tested for the reference test Gazelle as well as the gold standard cation exchange high performance liquid chromatography (CE-HPLC). Low serum ferritin levels are known to interfere with the production of HbA2 and in turn lead to false negative results. Hence, the study population was divided into two categories with respect to a cut off value of 15ng/dl of serum ferritin and the results were analyzed. Results Overall diagnostic accuracy of Gazelle for detecting BTT was found to be 95.3 per cent with a confidence interval (CI) of (92.9 - 97.1) and the sensitivity was 94.5 per cent with a 95% CI of (84.8 - 98.8). When analyzed by the serum ferritin level the diagnostic accuracy was found to be 94.7 per cent (91.1% - 97.1%) and 95.7 per cent (91.8% - 98.1%) for participants with serum ferritin level as > 15 ng/ml and < 15 ng/ml, respectively. Interpretation & conclusions This study found Gazelle to be a good screening tool for β-thalassemia trait with high sensitivity, specificity and accuracy. However, it is recommended that the final confirmation of the diagnosis done by a diagnostic test like HPLC or Capillary Zone Electrophoresis (CZE).

Digital light processing 3D printing of polymerizable ionic liquids towards carbon capture applications

This study presents new 3D printable materials based on ad-hoc synthesized photocurable imidazolium ionic liquids (ILs) with bis(trifluoromethanesulfonyl)imide (NTf2)− as counterion and two different alkyl chain's structures at the cation, with enhanced CO2 capture properties. The molecular structure of the synthesized ILs was confirmed through NMR technique and a polymerization study was carried out, by means of photorheological tests and FT-IR analyses, on formulations containing a crosslinking monomer (PEGDA). The study confirmed the good reactivity of the formulations that makes them suitable for digital light processing (DLP) 3D printing technique. Simple membranes were then tested through high pressure CO2 uptake analysis to estimate their capture efficiency, comparing the results with the standard room temperature ionic liquid (RTIL) counterpart, and evidencing an increase of CO2 absorption regardless the pressure applied. At last, complex gyroid-like structures incorporating the synthesized ILs were successfully 3D printed, showing the remarkable ability of these materials to be processed with 3D printing technology while maintaining the great CO2 capture performances of ionic liquids. This preliminary work paves the way for the implementation of “ad-hoc” designs to create filters or devices to enhance the CO2 capture.

A Cross-Sectional Exploratory Study of Cardiovascular Risk Biomarkers in Non-Obese Women with and without Polycystic Ovary Syndrome: Association with Vitamin D.

Vitamin D is proposed to have a protective effect against cardiovascular disease, though the mechanism is unclear. Vitamin D deficiency is common in polycystic ovary syndrome (PCOS), where it is strongly related to obesity, insulin resistance (IR) and risk of cardiovascular disease. To determine if the inherent pathophysiology of PCOS or vitamin D levels are linked to dysregulation of cardiovascular risk proteins (CVRPs), a study in non-obese women with PCOS and without IR was undertaken. Our hypothesis was that the levels of vitamin D3 and its active metabolite would be associated with CVRPs comparably in women with and without PCOS. In women with PCOS (n = 29) and controls (n = 29), 54 CVRPs were determined by Slow Off-rate Modified Aptamer (SOMA)-scan plasma protein measurement and correlated to 25-hydroxyvitamin D3 (25(OH)D3) and the active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) measured by gold standard isotope-dilution liquid chromatography tandem mass spectrometry. Women with PCOS had comparable IR and systemic inflammation (normal C-reactive protein) to control women, though had higher free androgen index and anti-Mullerian hormone levels. 25(OH)D3 and 1,25(OH)2D3 levels did not differ between groups. Nine CVRPs were higher in PCOS (p < 0.05) (Galectin-9, Brother of CDO, C-motif chemokine 3, Interleukin-18 receptor-1, Thrombopoietin, Interleukin-1 receptor antagonist protein, Programmed cell death 1 ligand-2, Low-affinity immunoglobulin gamma Fc-region receptor II-b and human growth hormone), whilst 45 CVRPs did not differ. 25(OH)D3 correlated with five CVRPs in PCOS and one in controls (p < 0.05). Despite the women with PCOS not exhibiting overt systemic inflammation, 9 of 54 CVRPs were elevated, all relating to inflammation, and 5 of these correlated with 25(OH)D3, suggesting an ongoing underlying inflammatory process in PCOS even in the absence of obesity/IR.

AgTCNQ nanoshuttle as a novel organic electrochemiluminescence emitter for ultrasensitive label-free detection of aflatoxin B1

The search for novel efficient organic electrochemiluminescence (ECL) emitters is still an active and ongoing topic. Herein, a well-known metal–organic semiconducting charge transfer structure, AgTCNQ, is identified as a promising organic ECL emitter. AgTCNQ nanoshuttles were synthesized and used for the first time to demonstrate robust cathodic ECL emission with K2S2O8 as a coreactant. The ECL mechanism of the AgTCNQ nanoshuttles was investigated, revealing a red-shifted ECL emission attributed to surface states. Leveraging the strong and stable ECL of AgTCNQ nanoshuttles, a label-free ECL immunosensor was developed for the sensitive detection of aflatoxin B1 (AFB1) in Chinese herbal medicine. The immunosensor demonstrated excellent analytical performance with a linear range of 3.16 × 10−15–3.16 × 10−13 g/mL, a low detection limit of 9.33 × 10−16 g/mL, and good stability and reproducibility. Selectivity tests and detection in Chinese herbal medicines validate the specificity and feasibility of the proposed ECL immunosensor for AFB1 detection. The precision and accuracy of the immunosensor are verified by comparison with the standard high-performance liquid chromatography method. Overall, this study introduces a novel type of organic ECL nanoemitter and highlights the potential of AgTCNQ nanoshuttles in the development of sensitive and selective ECL biosensors for diverse analytical applications.

Iron-copper nanozyme mimicking laccase for colorimetric determination of deoxynivalenol in feed

Due to the simplicity of their synthesis, robust stability, and adjustable enzymatic activities, nanozymes are particularly effective in inducing changes in substrate coloration, thus proving to be invaluable tools in colorimetric analysis. In this study, terephthalic acid was employed as an organic ligand to synthesize an iron-copper nanozyme with laccase activity using a one-pot hydrothermal method. Remarkably, the introduction of deoxynivalenol (DON) enhanced the laccase activity, significantly deepening the substrate’s color. The absorbance displayed a strong correlation with DON concentrations ranging from 5 μM to 35 μM, following the linear equation Y = 0.03097x + 0.00883 with a correlation coefficient (R2) of 0.994, and the limit of detection (LOD) was found to be 0.59 μM. This developed colorimetric method was then applied to determination DON in wheat, wheat bran, and corn samples, exhibiting relative standard deviations (RSD) between 1.5 % and 2.8 %. The analytical results were consistent with those obtained using the standard high performance liquid chromatography (HPLC) method. Therefore, this rapid, sensitive, and cost-effective technique promises efficient determination of DON in feed samples.

Battery Electrolyte Design for Electric Vertical Takeoff and Landing (eVTOL) Platforms

AbstractThe development of robust and high‐performance battery systems is crucial for the advancement of Electric Vertical Takeoff and Landing (eVTOL) vehicles for urban air mobility. This study evaluates the performance of different lithium‐ion battery chemistries under Electric Vertical Takeoff and Landing (eVTOL) load profiles. The actual flight data coupled with physical models is used to create discharge profiles for testing on developed lithium‐ion cells for eVTOLs. The performance of a standard liquid electrolyte (1.2 M LiPF6 in EC:EMC), labeled Gen‐2, is benchmarked and compared with a fast‐charging electrolyte (1.2 M LiFSI in EC:EMC), labeled XFC. Cell analysis involves the use of various techniques, such as impedance spectroscopy, polarization curves, and capacity retention measurements. Capacity retention is stable for both systems over 500 cycles, but unique discharge capacity trends are observed for different mission segments. During the initial takeoff hover stages, Gen‐2 electrolytes experience substantial voltage fade, while XFC electrolytes maintain consistent behavior. In general, the Gen‐2 electrolyte demonstrated lower discharge overpotentials and higher decay during cycling compared to the XFC electrolyte. This work highlights the complexity of eVTOL battery behavior and provides insights into battery system design, contributing to the advancement of battery energy storage solutions for urban air mobility.

Dietary Lysine Requirements of Older Adults Stratified by Age and Sex

BackgroundCurrent recommendation for lysine in older adults, 30 mg/kg/d, is based on young adult data. Evidence suggests that amino acid requirements may differ between young and old adults with both sex and age having an effect in the elderly. ObjectivesThis study aimed to define the lysine requirements in healthy older adults using the indicator amino acid oxidation (IAAO) method with L-[1-13C] phenylalanine as the indicator and to compare the derived estimates based on age: 60–69 y and >70 y. MethodsFourteen healthy males and 16 healthy females [>60 y, body mass index (BMI) = 26.3 kg/m2] were randomly assigned to receive 3–7 lysine intakes from 10 to 80 mg/kg/d. Subjects were adapted to a standard liquid diet providing 1.0 g/kg/d protein and adequate energy, for 2 d, with indicator oxidation measurements performed on day 3. The rate of release of 13CO2 from the oxidation of L-[1-13C] phenylalanine was measured in breath. A 2-phase linear mixed-effect model, and parametric bootstrap were used to determine mean lysine requirements and the 95% confidence intervals (CIs). The overlap of the 95% CI between the 2 age groups were used to compare the requirement estimates. The null hypothesis was accepted if the interval contained zero. ResultsThe mean and upper 95% CI of the lysine requirement for females were 32.9 and 40.9 and 46.2 and 53.7 mg/kg/d for those aged 60–69 y and >70 y, respectively. The mean and upper 95% CI of the lysine requirement for the 2 groups of males were not different so was combined to yield a mean and 95% CI of 32.2 and 38.2 mg/kg/d. ConclusionsTo our knowledge, this is the first study to report on the lysine requirement in adults aged >60 y. These results provide a basis from which the adequacy of diets to meet lysine needs of older adults can be assessed.The trial was registered at clinicaltrials.gov as NCT02008955 (https://clinicaltrials.gov/study/NCT02008955).

Nanostructured rhodamine B/aluminosilicate extracted sugarcane bagasse modified with tobacco-derived carbon quantum dot as ratiometric fluorescence probe for determination of tetracycline

Tetracycline (TC), as a widely used antibiotic, is very useful in treating bacterial infections. However, its residues in animal foodstuffs can enter the human body through the food cycle and causes severe and chronic diseases. On the other hand, due to its weak non-biodegradability, it is considered a threat to the environment. In this regard, the development of sensing methods to detect and measure TC is need of the hour. Herein, a dual-emission fluorescence sensor based on porous aluminosilicate structure (ASS) with rough surface hexagonal shape morphology and pore diameter less than 2 nm was prepared. The porous AAS was modified by post-modification method with blue carbon dots (CDT) and rhodamine B (RB) as two fluorophores to develop the ratiometric fluorescence (RF) sensor (CDT-AAS/RB). Nanostructured CDT-AAS/RB emitted two resolved peaks at 445 and 585 nm , which were dramatically quenched in the presence of TC. The RF sensor, with excellent sensitivity, was able to measure TC over the linear range of 0.001–150 μM with a limit of detection of 5.4 nM in the aqueous phosphate buffer. Moreover, the AAS component granted high selectivity and anti-interference ability to the sensor. In addition, the stability of the sensor was greatly improved due to the non-accumulation of CDT nanoparticles and RB molecules in the presence of the AAS. The proposed method was able to determine TC in complex real samples with satisfactory recovery, and the obtained results were validated with standard high-performance liquid chromatography technique.

Isolation of Adeno-associated Viral Vectors Through a Single-step and Semi-automated Heparin Affinity Chromatography Protocol.

Adeno-associated virus (AAV) has become an increasingly valuable vector for in vivo gene delivery and is currently undergoing human clinical trials. However, the commonly used methods to purify AAVs make use of cesium chloride or iodixanol density gradient ultracentrifugation. Despite their advantages, these methods are time-consuming, have limited scalability, and often result in vectors with low purity. To overcome these constraints, researchers are turning their attention to chromatography techniques. Here, we present an optimized heparin-based affinity chromatography protocol that serves as a universal capture step for the purification of AAVs. This method relies on the intrinsic affinity of AAV serotype 2 (AAV2) for heparan sulfate proteoglycans. Specifically, the protocol entails the co-transfection of plasmids encoding the desired AAV capsid proteins with those of AAV2, yielding mosaic AAV vectors that combine the properties of both parental serotypes. Briefly, after the lysis of producer cells, a mixture containing AAV particles is directly purified following an optimized single-step heparin affinity chromatography protocol using a standard fast protein liquid chromatography (FPLC) system. Purified AAV particles are subsequently concentrated and subjected to comprehensive characterization in terms of purity and biological activity. This protocol offers a simplified and scalable approach that can be performed without the need for ultracentrifugation and gradients, yielding clean and high viral titers.

Carboxyethylsilanetriol-Coated Magnetic Nanoparticles as an Ultrasensitive Immunoplatform for Electrochemical Magnetosensing of Cotinine.

In the present study, an innovative and simple electrochemical magneto biosensor based on carboxyethylsilanetriol-modified iron oxide (Fe3O4) magnetic nanoparticles was designed for ultrasensitive and specific analysis of cotinine, an important marker of smoking. Anticotinine antibodies were covalently immobilized on carboxylic acid-modified magnetic nanoparticles, and the cotinine-specific magnetic nanoparticles created a specific surface on the working electrode surface. The use of magnetic nanoparticles as an immobilization platform for antibodies provided a large surface area for antibody attachment and increased sensitivity. In addition, the advantages of the new immobilization platform were reusing the working electrode numerous times, recording repeatable and reproducible signals, and reducing the necessary volume of biomolecules. The specific interaction between cotinine and cotinine-specific antibody-attached magnetic nanoparticles restricted the electron transfer of the redox probe and changed the impedimetric response of the electrode correlated to the concentration of cotinine. The magneto biosensor had a wide detection range (2-300 pg/mL), a low LOD (606 fg/mL), and an acceptable recovery (97.24-105.31%) in real samples. In addition, the current biosensor's measurement results were in good agreement with those found by the standard liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) methods. These results showed that a simple impedimetric immunosensing platform was generated for the cotinine analysis.

Integration of a hamper pad on test strips for improved sensitivity of carbendazim detection

Lateral flow immunoassays (LFIAs) are widely used to determine carbendazim (CBZ) residues in food products due to their advantages of low cost, ease and rapid use, on-site detection capability. However, conventional LFIAs have low detection sensitivity. Although improvements have been made to increase the sensitivity, it is not sufficient. Here, a hamper pad, polyvinyl alcohol coated on a nitrocellulose membrane, was integrated to enhance the sensitivity of LFIA for CBZ detection. The hamper pad was inserted between the conjugated and nitrocellulose pads to delay the flow rate, thereby increasing the possibility of the antibody and target analyte binding. This platform exhibited a fourfold sensitivity increase in CBZ detection compared with the conventional LFIA, and its limit of detection was 1.6 ng/mL. In addition, a single-step operation was successfully applied to detect CBZ in rice (white rice, brown rice, sticky rice, and paddy) and soybean samples, with acceptable recoveries of 93.6%–120.0%. This novel device was compared to the standard high-performance liquid chromatography method, which shows high accuracy with a Kappa coefficient of 0.91. Therefore, improved sensitivity with a rapid, simple, and inexpensive device could facilitate the detection of CBZ residues in agricultural products for on-field screening and improved user-friendliness.

High-Throughput Capillary Liquid Chromatography Using a Droplet Injection and Application to Reaction Screening.

The cycle time of a standard liquid chromatography (LC) system is the sum of the time for the chromatographic run and the autosampler injection sequence. Although LC separation times in the 1-10 s range have been demonstrated, injection sequences are commonly >15 s, limiting throughput possible with LC separations. Further, such separations are performed on relatively large bore columns requiring flow rates of ≥5 mL/min, thus generating large volumes of mobile phase waste when used for large scale screening and increasing the difficulty in interfacing to mass spectrometry. Here, a droplet injector system was established that replaces the autosampler with a four-port, two-position valve equipped with a 20 nL internal loop interfaced to a syringe pump and a three-axis positioner to withdraw sample droplets from a well plate. In the system, sample and immiscible fluid are pulled alternately from a well plate into a capillary and then through the injection valve. The valve is actuated when sample fills the loop to allow sequential injection of samples at high throughput. Capillary LC columns with 300 μm inner diameter were used to reduce the consumption of mobile phase and sample. The system achieved 96 separations of 20 nL droplet samples containing 3 components in as little as 8.1 min with 5-s cycle time. This system was coupled to a mass spectrometer through an electrospray ionization source for high-throughput chemical reaction screening.

Simultaneous Bdellovibrio bacteriovorus–Bacteriophage dosing with SODIS for treatment of environmental water sources

The predatory bacterium Bdellovibrio bacteriovorus HW1 and bacteriophage ABTW1 were applied simultaneously, with solar disinfection (SODIS), for the reduction of Acinetobacter baumannii in environmental water sources. The B. bacteriovorus HW1 and ABTW1 dosing protocol was optimised, with results indicating that the simultaneous application of B. bacteriovorus HW1 and ABTW1 at 0 h resulted in the greatest log reduction (5.66 and 3.97 log based on CFU/mL and GC/mL, respectively) in A. baumannii over the 96 h co-culture period. Similar log reductions (5.24 and 3.85 log reduction based on CFU/mL and GC/mL, respectively) were however, obtained for the initial dosing of B. bacteriovorus at 0 h, and addition of bacteriophage ABTW1 at 24 h. A lyophilised bacteriophage formulation (0.5 M sucrose and 1% gelatine) was then compared to the standard liquid bacteriophage inoculum, with B. bacteriovorus, in upscaled volume trials. However, as similar A. baumannii log reduction results were obtained, the standard bacteriophage liquid inoculum, with B. bacteriovorus, was assessed as a pre-treatment to 6 h SODIS. The B. bacteriovorus HW1-bacteriophage ABTW1 combination as well as the B. bacteriovorus HW1 only pre-treatment, both with SODIS, significantly reduced the A. baumannii cell counts (8.32 and 8.38 log, respectively) to below detection limit (BDL). Molecular analysis however, showed that A. baumannii persisted (∼ 3 log reduction) after the application of all treatment protocols. It is thus recommended that the efficiency of the B. bacteriovorus-bacteriophage combination is further optimised to improve the lytic effect of both biological control agents, particularly the bacteriophage, on their prey.

Development of a SERS aptasensor for the determination of L-theanine using a noble metal nanoparticle-magnetic nanospheres composite.

An ultrasensitive surface-enhanced Raman spectroscopy (SERS) aptamer sensor (aptasensor) using a noble metal nanoparticle-magnetic nanospheres composite was developed for L-theanine detection. It makes use of Fe3O4@Au MNPs and Au@Ag NPs embedded with the Raman reporter 4-mercaptobenzoic acid (4MBA). Au@4MBA@Ag NPs modified by aptamer and Fe3O4@Au MNPs modified by cDNA created the aptasensor with the strongest Raman signal of 4MBA through the specific binding of the aptamer. With the preferred binding of L-theanine aptamer to L-theanine, Au@4MBA@Ag NPs were released from Fe3O4@Au MNPs, causing a linear decrease in SERS intensity to achieve the SERS detection of the L-theanine. The SERS peak of 4MBA at 1078cm-1 was used for quantitative determination. SERS intensity showed a good log-linear relationship within the range 10-10 to 10-6Mof L-theanine. Theaptasensor has a high selectivityfor L-theanine compared with other twelve testedanalytes. Hence, thisaptasensor is a promising analytical tool for L-theanine detection. The developedmethod was appliedto the analysis of real samples, demonstrating excellent performance. The comparison with the standard liquid chromatography mass spectrometry methodshowed an error within 20%.

Point-of-Care Diagnostic Test for Beta-Thalassemia.

Hemoglobin (Hb) disorders are among the most common monogenic diseases affecting nearly 7% of the world population. Among various Hb disorders, approximately 1.5% of the world population carries β-thalassemia (β-Thal), affecting 40,000 newborns every year. Early screening and a timely diagnosis are essential for β-thalassemia patients for the prevention and management of later clinical complications. However, in Africa, Southern Europe, the Middle East, and Southeast Asia, where β-thalassemia is most prevalent, the diagnosis and screening for β-thalassemia are still challenging due to the cost and logistical burden of laboratory diagnostic tests. Here, we present Gazelle, which is a paper-based microchip electrophoresis platform that enables the first point-of-care diagnostic test for β-thalassemia. We evaluated the accuracy of Gazelle for the β-Thal screening across 372 subjects in the age range of 4-63 years at Apple Diagnostics lab in Mumbai, India. Additionally, 30 blood samples were prepared to mimic β-Thal intermediate and β-Thal major samples. Gazelle-detected levels of Hb A, Hb F, and Hb A2 demonstrated high levels of correlation with the results reported through laboratory gold standard high-performance liquid chromatography (HPLC), yielding a Pearson correlation coefficient = 0.99. This ability to obtain rapid and accurate results suggests that Gazelle may be suitable for the large-scale screening and diagnosis of β-Thal.

Environmentally sustainable ethyl levulinate synthesis from delignified sugarcane bagasse using ternary eutectic solvent under MW-xenon irradiation: engine performance and emission assessment.

For the first time, a synergistic energy-efficient combination of microwave-xenon (MW-XE) irradiations in presence of photoactive ternary acidic deep eutectic solvents (TADES) has been applied for intensification of ethyl levulinate synthesis from delignified sugarcane bagasse (DSB) under mild (90min, 90°C) and environmentally benign process conditions. The Taguchi orthogonal designed optimized conditions (20 W/cm3 of MW specific irradiation power input, 1 mol/mol of FeCl3 to citric acid ratio, 90min of reaction time, 150 W of XE specific power input) rendered maximum 61.3mol% of EL yield (selectivity: 87.70 [Formula: see text] 0.5%). Remarkably, synergistic effect of MW and XE irradiation significantly enhanced the EL yield (61.3mol%) compared to the individual MW (34.52mol%) and XE (22.67mol%) irradiation at otherwise optimized reaction conditions. Moreover, the MWXE irradiated reactor (MWXER) exhibited a significant 79.10% increase in EL yield compared to the conventional thermal reactor (CTR), at the expense of 10% less energy consumption. The ethyl levulinate could be recovered efficiently through green protocol from reaction mix resulting in high purity (97 [Formula: see text] 0.5%) and TADES was sustainably reused in the process. The optimally generated product EL when blended (5 and 10 vol.%) with B10 and B20 (10% and 20% biodiesel-diesel blend) could provide 21-31% reduction in HC and 7.3-36% reduction in CO in comparison with petro-diesel. It was also explored that, at similar optimal parametric combinations, the TADES produced 29.5% greater EL yield in comparison with the standard ionic liquid BMIMCl. The life cycle environmental impact analysis (LCEIA) of the overall process revealed that the 5 vol.% EL blending with B10 contributed lowest environmental impacts mitigating marine ecotoxicity, human toxicity, fossil depletion, and climate change by 77.9%, 77.4%, 78.4% and 77.5%, respectively.

Morphology, repulsion, and ordering of red blood cells in viscoelastic flows under confinement.

Red blood cells (RBC), the primary carriers of oxygen in the body, play a crucial role across several biomedical applications, while also being an essential model system of a deformable object in the microfluidics and soft matter fields. However, RBC behavior in viscoelastic liquids, which holds promise in enhancing microfluidic diagnostic applications, remains poorly studied. We here show that using viscoelastic polymer solutions as a suspending carrier causes changes in the clustering and shape of flowing RBC in microfluidic flows when compared to a standard Newtonian suspending liquid. Additionally, when the local RBC concentration increases to a point where hydrodynamic interactions take place, we observe the formation of equally-spaced RBC structures, resembling the viscoelasticity-driven ordered particles observed previously in the literature, thus providing the first experimental evidence of viscoelasticity-driven cell ordering. The observed RBC ordering, unaffected by polymer molecular architecture, persists as long as the surrounding medium exhibits shear-thinning, viscoelastic properties. Complementary numerical simulations reveal that viscoelasticity-induced repulsion between RBCs leads to equidistant structures, with shear-thinning modulating this effect. Our results open the way for the development of new biomedical technologies based on the use of viscoelastic liquids while also clarifying fundamental aspects related to multibody hydrodynamic interactions in viscoelastic microfluidic flows.

Post-collection purity correction for internal standard correction-high performance liquid chromatography-quantitative nuclear magnetic resonance.

Quantitative nuclear magnetic resonance (qNMR) has a potential risk of inaccurate quantification of complex organic compounds with low purity due to incomplete separation of the impurity signals and the target component signals. The high performance liquid chromatography-qNMR (HPLC-qNMR) method removes impurities from the sample by HPLC and accurately determines the purity of the sample by qNMR, avoiding the laborious, time-consuming, and costly step of qualitative and quantitative determination of impurities in conventional mass balance methods. An improved method, named post-collection purity correction for internal standard correction-HPLC-qNMR (ISC-HPLC-qNMR), was developed and demonstrated on a complex compound oxytetracycline with low purity. In this method, a correction factor was introduced to compensate for the inability to achieve 100% purity through the HPLC purification procedure. The purity value with standard deviation of the oxytetracycline study material using this method was 82.00% ± 0.82%, while that obtained from the conventional qNMR with deconvolution was 81.70% ± 0.35%. The consistency of these results demonstrated that the improved method extends the applicability to the samples where HPLC is not capable of purifying complex compounds with low purity to near 100%, especially containing highly similar structural-related impurities. Furthermore, this method allows purification and quantification without the need to identify impurities in the sample, resulting in significant savings of time and cost. Additionally, it effectively compensates for the limitations of qNMR deconvolution in handling peak overlap in the sample.

Tailoring molecular recognition in predesigned multifunctional enzyme mimicking porphyrin imprinted interface for high affinity and differential selectivity; sensing etoposide in lung cancer patients

Nanozymes are cost-effective and robust but they lack specificity and selectivity, limiting their potential practical applications. Herein, molecularly imprinted polymers (MIPs) were grown in combination with multifunctional 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin (THPP) oxidase-like nanozyme to engineer THPP@MIP interface with high affinities and differential selectivity for structurally related target analytes. THPP nanozyme displayed a high level of predefined binding affinity for etoposide (ETO), and served as a predesigned functional monomer to rationally tailor the selectivity of THPP@MIP surface in the presence of different guest molecules. THPP nanozyme in combination with conventional monomers was imprinted on a portable and disposable cellulose paper matrix under UV light to create a UV-cured imprinted interface for optical detection of ETO. The THPP@MIP enzyme mimicking interface, having ETO specific and selective target recognition pockets, catalyzed the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to generate visible blue oxidized TMB (oxTMB) without exogenous hydrogen peroxide (H2O2). The ETO binding on the THPP@MIP surface blocked the channels for TMB access to THPP cavities. The THPP@MIP sensor permitted to detect ETO in the linear range of 0.005–10 μg mL−1, with a limit of detection (LoD) of 0.002 μg mL−1, and showed a remarkable specificity and selectivity against other drug molecules. Furthermore, the THPP@MIP sensor successfully differentiated the serum samples of lung cancer patients and healthy volunteers. The obtained results were validated with standard High performance liquid chromatography-mass spectrometry (HPLC/MS) analysis of the serum samples. Additionally, ETO injection/infusion solutions and ETO-free serum samples were used to perform the matrix effect and recovery studies. This work demonstrates that molecular imprinting with predesigned, enzyme mimicking, high-affinity functional monomer can serve as a highly selective and specific universal interface for broad spectrum sensing applications in various analytical domains.