Introduction: Microfluidics refers to the science and technology of fluid flow at the microscale. Nowadays, microfluidic devices are ubiquitous, which makes it crucial to develop rapid and accessible microchip fabrication methods to realize all their potential applications. This work presents three alternative low-cost microfluidic device fabrication methods, accessible for fast prototyping in low-income or non-specialized laboratories.

Methods: Three alternative methods for microfluidic device fabrication that require low equipment investment and commercially available materials are compared: a) 3D precision cutting on adhesive sheets (simile crystal acetate, PVC film, packaging tapes, etc.) using computer numerical control (CNC) laser engraving (Neje® DK-8-KZ, 405nm wavelength, 1500 mW)); b) PDMS chip obtention from a master mold implemented on a chemically engraved copper-laminated board. The mold is obtained using chemical etching after transferring the channel design using laser prints and a heat source. Then, the soft lithography process is carried out on the mold with PDMS. The chip is sealed with a self-adhesive PCV film. c) 3D digital light processing (DLP) resin printing (Hellbot Apolo Pro printer). The chip is designed in a computer-aided design software environment (Fusion 360) where the printing parameters are configured. A ready-to-use chip is obtained.

Results and Discussion: The three proposed methods successfully achieved microfluidic device fabrication. The chips are capable of transporting fluids by capillarity and by external pumping. Each of these methodologies is low-cost and has advantages and disadvantages when compared to the others. The versatility and affordability of these protocols significantly expand the possibilities for research and experimentation in microfluidics, allowing a broader range of laboratories and professionals to contribute to the advancement of this discipline.

Conclusions: Low-cost microfluidic device fabrication can be achieved with the three affordable methodologies proposed and commercially available materials.

The development and deployment of monoclonal antibodies (mAbs) for therapeutic applications hinge on meticulous functional characterization to ensure efficacy and safety. This critical review delves into the characterization processes for a GLP-1 analog used in diabetes treatment and a high molecular weight mAb for arthritis. Despite promising clinical outcomes, these biologics encounter significant challenges, such as proteolytic degradation and immunogenic responses. Binding assays, activity assessments, and in vivo studies offer insights into their therapeutic mechanisms, yet discrepancies between laboratory and clinical responses highlight the need for rigorous assay optimization. Addressing these challenges involves innovative approaches and robust validation protocols. For GLP-1 analogs, detailed binding assays are essential to confirm receptor specificity and activity, while in vivo studies are critical for understanding pharmacokinetics and pharmacodynamics. For high molecular weight mAbs targeting arthritis, overcoming immunogenicity requires advanced engineering techniques to enhance biocompatibility and reduce adverse reactions. The continuous advancement in mAb development is propelled by these innovative methodologies, ensuring that new therapeutics meet the stringent requirements for clinical success. Ultimately, this progress enriches the treatment landscape for various diseases, offering improved outcomes for patients and expanding the potential of biologic therapies. Through ongoing research and development, the characterization and optimization of mAbs remain pivotal in translating laboratory discoveries into effective clinical treatments.

Introduction: Thrombosis is a global health concern that is linked to a number of cardiovascular events and their related death rates. At present, there is a need for the mathematical description of the process of thrombus formation in order to introduce new devices and decrease a number of complications.

Methods: We proposed a mathematical model of thrombus formation in a vessel, taking into account the coagulation and blood flow effects on fibrin clot growth. The mathematical formulation includes non-steady Navier–Stokes equations and incompressibility equations to describe the blood motion and five coupled convection–diffusion reaction equations to describe the temporal and spatial evolution of thrombus. The sub-model of blood coagulation including the kinetics of metabolites (VIIIa and Xa factors, thrombin, protein C, and fibrin concentrations) was adopted. A special equation connecting thrombus growth rate and fibrin concentration based on the proposed hypothesis was also introduced.

Results and Discussion: The concentrations of the components of the blood coagulation cascade were computed. The dependence of thrombus size on velocity magnitudes was also obtained. Additionally, pressure distribution and wall shear stress were evaluated. The maximum flow rate increased by 14% with a thrombus size of 16 mm³. The proposed model describes changes in the key metabolites of the blood coagulation cascade. The results were compared with clinical and in vitro data from the literature and showed a good corelation.

Conclusions: A simulation of thrombus growth is planned to be incorporated into problems related to the mid- and long-term predictions of cardiovascular devices' behavior, such as grafts, stents, and artificial aortic valves.

This research was funded by the Ministry of science and higher education of the Russian Federation (Project № FSNM-2024-0009).

Authors and Affiliations:

Nikita Pil (nikitapil32@gmail.com) * / Biofluids laboratory, Perm National Research Polytechnic University, Perm, Komsomolskiy Prospect 29

Alex G. Kuchumov (kychymov@inbox.ru) / Biofluids laboratory, Perm National Research Polytechnic University, Perm, Komsomolskiy Prospect 29

Introduction:
Nowadays, the therapeutic administration of essential oils is gaining high interest. For instance, oregano oil possesses remarkable effects, such as antioxidant, anti-inflammatory, antibacterial, antifungal and antiviral activity. However, it is characterized by low aqueous solubility, which makes its application difficult and compromises its effects. Loading the oil into nanoparticles is an appropriate strategy to improve its use. Nanogels prepared from natural polymers are considered alternative nanosized drug delivery systems capable of improving the characteristics of hydrophobic substances.

Methods:
Oregano oil was loaded into nanogels prepared from chitosan and albumin by emulsification. The nanogel system was physicochemically characterized via DLS, TEM, IR and XRD analysis. A dialysis method was applied to study its in vitro release. The antiviral activity of the nanoparticles loaded with oregano oil was tested on Betacoronavirus 1 (S379 Riems) using a direct treatment approach. The MTT dye assay was applied for measurement of the cell viability. The cytopathic effect was evaluated microscopically.

Results and Discussion:
The encapsulation efficiency of the oil in the nanogel particles was approx. 40%. The nanogels possessed a small mean diameter of 26 nm, a narrow size distribution and a positive zeta-potential (+20.6 mV). TEM confirmed their small size. The in vitro dissolution test showed that approx. 100% of the oil was released for 24 h. The IR and XRD analyses confirmed the successful entrapment of the oil. The nanoparticles showed more than 40% protection of the treated cells at concentrations between 15 and 30 µg/mL as compared to the non-treated virus-infected control.

Conclusions:
Nanogels prepared from the natural polymers chitosan and albumin could be considered appropriate carriers for the delivery of oregano oil. Their moderate activity against Betacoronavirus 1 could be a platform for further investigations of the pharmacodynamics and possible combinations with clinically applied chemotherapeutics.

This work presents a physiological-based model of the process of insulin production in relationship to the presence of glucose in the intestinal tract. Insulin is secreted by pancreatic β-cells in the Islets of Langerhans and it plays a fundamental role in both the proper functioning of the energy metabolism and glucose homeostasis. This process is regulated and influenced by numerous factors, such as glucose, but there are numerous other substances that can influence the release of insulin; among these there are the GIP (glucose-dependent insulinotropic peptide) and the GLP-1 (glucagon-like peptide), hormones secreted by the intestine as a response to the nutrients ingested. These two polypeptides are called ”incretins”, and they have an ”insulinotropic” effect, increasing the insulin production while suppressing glucagon. The effects of these two incretin hormones are the cause of greater insulin blood concentrations during an Oral Glucose Tolerance Test in comparison to what is observed after an Intra-Venous Glucose Tolerance Test. This work presents a mathematical model constituted by eight ordinary differential equations aiming to reproduce both the insulin production modulated by the incretins as well as their time course over time following a bolus of oral-administered glucose. The proposed model adapts very well to the observations and a sensitivity analysis was employed to assess the most sensitive parameters in determining the trend of the variables of interest.

The objective of this study was to develop a multicompartmental mathematical model that allows for the reproduction of the function of the gastrointestinal system in silico. This model was used to test the bioavailability of drugs, which is defined as the fraction of a drug administered orally that reaches the systemic circulation. This study employed an innovative approach that considered the individual variability of patients in order to calibrate the therapy using non-invasive preclinical data and accessible measurements. The model is a physiologically based pharmacokinetic (PBPK) model, which aims to overcome the simplifications typically adopted in the literature. It employs the typical tools of chemical engineering, transport phenomena, and human physiological and anatomical knowledge. The developed pharmacokinetic model is not limited to representing the transport of drugs and their interactions with ingested foods; it also describes several physiological aspects that quantitatively regulate the distribution, absorption, and elimination of drugs. Nevertheless, the model only contains a limited number of parameters: the permeability constants of jejunum, ileum, and colon membranes and the drug removal rates in both the blood and cellular compartments. The model was validated by testing it on two drugs, ketoprofen and ibuprofen, which yielded satisfactory results in accordance with the existing literature.

Three-dimensional printing, especially the technology of fused deposition modelling (FDM), is more and more often used for the production of different objects, especially those that are produced only in small numbers or that have complicated shapes that cannot be produced in a different way. The increase in 3D-printed objects, on the other hand, leads to an increase in polymeric waste that has to be taken into account. One way to reduce this problem is using biodegradable thermoplastic polymers instead of petroleum-based plastics, which are responsible for “white pollution”. Amongst the biodegradable, biobased polymers used for 3D printing, poly(lactic acid) (PLA) is most commonly used, while polyhydroxyalkanoates (PHA) and a few other materials are also under investigation for 3D printing. PLA, however, has a much slower degradation rate under environmental conditions than other biopolymers and actually needs commercial composting. This is why a study was performed investigating the printability of different biobased FDM filaments with better biodegradability. In addition, the mechanical properties and surface morphology of the 3D-printed objects were compared with those of PLA and PETG. Due to the potential use of such filaments in tissue engineering and other biomedical applications, the chemical stability and the possibility of autoclaving the biobased materials were also successfully tested. The results of this study show the potential of new biobased FDM filaments for biomedical and biotechnological applications.

Introduction: Natural enzymes play crucial roles in various biomedical fields, particularly in biosensing. Nevertheless, their use is often limited by high costs and limited stability. Therefore, there is an urgent need to develop artificial alternatives with enzyme-like properties and enhanced stability for low-cost biomedical applications. Nanozymes have emerged as a promising alternative to natural enzymes, offering advantages such as mimicking enzymatic functions, high catalytic stability, easy modification, and low fabrication costs. These attributes make nanozymes highly suitable for use in biosensors to amplify signals and improve detection performance. Precisely designing single-atom nanozymes (SANs) at the atomic level to achieve isolated metal active sites can significantly enhance their enzyme-like catalytic activity, thereby boosting their performance in biomedical applications.

Methods: We designed various SANs to mimic the structure of heme-based enzymes' active centres, achieving enzyme-like properties comparable to natural ones. Specifically, Fe-N-C-based SANs are reasonably designed via different strategies, including a secondary-atom-assisted method, MnO_x nanoconfinement, an ion-imprinted approach, and P atom adjustment strategies, etc.

Results: The SANs demonstrated superior robustness compared to natural enzymes, maintaining excellent stability under varying pH levels and temperatures. Their exceptional catalytic specificity for hydrogen peroxide suggests they could effectively replace natural peroxidases in high-sensitivity biosensing. To explore practical applications, we developed electrochemical sensors, immunosorbent assays, intercellular nanoprobes, and lateral-flow immunoassays based on SANs for biosensing and bioimaging.

Conclusions: The developed SANs exhibit excellent enzyme-like activity, selectivity, and stability due to their unique electronic and geometrical properties. These features offer substantial potential for substituting natural enzymes in various biomedical applications. To continuously monitor human health, we further integrated SANs into wearable microgrids. This development aims to meet the demands for autonomous, self-powered, self-regulated, and flexible wearable energy management and sensors, thereby enabling comprehensive healthcare monitoring and advanced human--machine interfacing.

In the realm of haematology, the transition from manual microscopic examination to automated cell morphology analysers as the gold standard remains an unachieved milestone. A pivotal impediment to this advancement is the inadequacy in the volume and fidelity of labelled cellular samples essential for the training of artificial intelligence (AI)-driven cell classification models. The process of deriving labeled cells from digital microscopic imagery necessitates meticulous human curation, which, given the extensive quantity of cells required, becomes onerous and fraught with quality control challenges.

This manuscript introduces an innovative methodology designed to significantly enhance the efficiency of the labelling process. Initially, we employed some techniques to mitigate the confounding effects of erythrocyte populations on leukocyte identification, thereby expediting subsequent cellular sorting procedures. Subsequently, leveraging state-of-the-art cell sorting technology, we executed label-free segregation of a targeted leukocyte subset, exemplified by monocytes, culminating in the acquisition of a highly purified monocyte suspension. We adhered to established slide preparation and staining protocols, such as the Wright--Giemsa staining method, to fabricate blood smears that preserve cellular morphology with minimal alteration. In the final phase, human annotators perform batch labelling of monocytes through the mediation of digital microscopic imagery of the smears. Consequently, the resultant digital microscopic images predominantly feature monocytes, with a negligible presence of other leukocyte classes.

By delineating non-monocytic cells with the annotation "not monocytes," annotators can efficiently designate the remaining cells as monocytes, thereby achieving batch labelling of the specified leukocyte class.

This approach not only augments the efficacy of manual labelling but also diminishes the laboriousness associated with the task, with the anticipation of concurrently elevating the calibre of labelling accuracy.

Medicinal plant extracts, rich in bioactive compounds like alkaloids, flavonoids, and terpenoids, exhibit diverse biological activities and are increasingly researched for pharmaceutical use. Algeria, abundant in medicinal plants, includes Tetraclinis articulata from the Cupressaceae family, traditionally used to treat various diseases due to its potent bioactive compounds. The leaves of T. articulata are especially valued for their therapeutic properties in Algerian traditional medicine. This study aimed to assess the antibacterial activity of an aqueous extract from T. articulata leaves against Klebsiella pneumoniae, alongside phytochemical analysis. The plant extracts were prepared by decoction; the phenolic compounds and flavonoids were screened using FeCl3 and Shinoda tests, respectively. The antibacterial activity was evaluated using the agar well method with Chloramphenicol as the reference antibiotic, and the Minimum Inhibitory Concentration (MIC) was determined using the broth microdilution method. Preliminary phytochemical screening revealed that the extract from the leaves of T. articulata is rich in phenolic compounds and flavonoids. The aqueous extract of T. articulata leaves exhibited significant inhibition of K. pneumoniae growth at a concentration of 200 mg/ml with an inhibition zone of 11 ± 0.00 mm and MIC = 25 mg/ml . This extract demonstrated efficacy in inhibiting the growth of K. pneumoniae. The use of the aqueous extract of T. articulata as an antibiotic to combat infections caused by K. pneumoniae could offer a natural and potentially effective alternative to traditional treatments, while helping to reduce the risk of antibiotic resistance.