Optimized Cell-Based Platform for Platelet-Free Detection of Heparin-Induced Thrombocytopenia Antibodies.

Accurate detection of heparin-induced thrombocytopenia (HIT) antibodies is crucial for diagnosing and managing thrombotic events. Conventional immunoassays, however, often lack specificity and require confirmatory testing with fresh human platelets. To address this limitation, we optimized our previously developed cell-based enzyme-linked immunosorbent assay (ELISA) for improved HIT detection under various experimental conditions.

Molecular Insights into the Interaction between CD147 and the SARS-CoV‑2 Spike Protein.

Cluster of differentiation 147 (CD147), a transmembrane glycoprotein, has been identified as a potential auxiliary receptor for the SARS-CoV-2 spike protein (SP), contributing to COVID-19 infection. However, the detailed binding characteristics of this interaction remain unclear. Here, we characterized SP-CD147 binding using Enzyme-Linked Immunosorbent Assay (ELISA) and single-molecule force spectroscopy (SMFS) under varying contact times and temperatures.

Droplet-based cell viability assay for analysis of spheroid formation, proliferation and high-resolution IC profiling.

Three-dimensional (3D) cell cultures or samples generated from biopsies are typically used as patient-specific models. As 3D cell cultures form cell-cell and cell-matrix interactions and mimic the situation better compared to monolayer cultures, they provide more reliable data for drug screening applications. In the field of drug screening, microfluidics is moving to the forefront for testing the efficacy of drugs, as measured by IC values.

A QCM-Based Biosensor to Detect HIT-like Antibodies: Differentiating KKO from RTO via FcγRIIA Interactions.

Heparin-induced thrombocytopenia (HIT) is a serious side effect that occurs in patients undergoing heparin therapy. The known risk factor is the presence of antibodies created against platelet factor 4 and heparin complexes (PF4/heparin) in the blood, which activate platelet Fc receptors (FcγRIIA). Although immunoassays have been developed for HIT diagnosis, their specificity remains low (∼50%) due to the binding of nonpathogenic antibodies to the same antigen (PF4/heparin).

Poly-(D,L)-Lactide-ε-Caprolactone-Methacrylate Is a Suitable Scaffold Material for In Vitro Cartilage Regeneration.

Due to the limited regeneration of cartilage, new implant materials are needed. Biodegradable polymers poly-(D,L)-lactide-ε-caprolactone-methacrylate (LCM) and polyamid-ε-caprolactone-methacrylate (ACM) were recently established and coated with heparin, making them able to prevent blood coagulation and cartilage mineralization. The aim of this study was to analyze the suitability of LCM and ACM alone or coated with heparin (the latter are abbreviated as LCMH and ACMH, respectively) as implant material for cartilage repair.

Effect of Sequential vs. Simultaneous Dual Growth Factor Release from Structured Heparin-Poly-Electrolyte Multilayer Coatings on Peri-Implant Bone Formation and Angiogenesis in Pig Mandibles.

The aim of the present study was to test the sequential and simultaneous release of rhBMP2 and rhVEGF165 from poly-l-lysine-heparin (PLL-Hep) poly-electrolyte multilayer (PEM) coating on titanium surfaces for their ability to enhance peri-implant bone formation and CD31 expression around disc-shaped titanium implants (5 × 7 mm) in mini-pig mandibles. Bare titanium surfaces loaded with respective growth factor combinations served as controls. Ten different surface conditions were tested exhibiting early VEGF release, early BMP release, simultaneous VEGF and BMP release, and sole VEGF/BMP release, respectively.

Dynamic cell culture modulates colon cancer cell migration in a novel 3D cell culture system.

The progression of cancer cell migration, invasion and subsequent metastasis is the main cause of mortality in cancer patients. Through creating more accurate cancer models, we can achieve more precise results, which will lead to a better understanding of the invasion process. This holds promise for more effective prevention and treatment strategies.

The Binding of the SARS-CoV-2 Spike Protein to Platelet Factor 4: A Proposed Mechanism for the Generation of Pathogenic Antibodies.

Pathogenic platelet factor 4 (PF4) antibodies contributed to the abnormal coagulation profiles in COVID-19 and vaccinated patients. However, the mechanism of what triggers the body to produce these antibodies has not yet been clarified. Similar patterns and many comparable features between the COVID-19 virus and heparin-induced thrombocytopenia (HIT) have been reported.

Flexible Toolbox of High-Precision Microfluidic Modules for Versatile Droplet-Based Applications.

Although the enormous potential of droplet-based microfluidics has been successfully demonstrated in the past two decades for medical, pharmaceutical, and academic applications, its inherent potential has not been fully exploited until now. Nevertheless, the cultivation of biological cells and 3D cell structures like spheroids and organoids, located in serially arranged droplets in micro-channels, has a range of benefits compared to established cultivation techniques based on, e.g.

Sclerostin Alters Tumor Cell Characteristics of Oral Squamous Cell Carcinoma and May Be a Key Player in Local Bone Invasion.

Localized jawbone invasion is a milestone in the progression of oral squamous cell carcinoma (OSCC). The factors that promote this process are not well understood. Sclerostin is known to be involved in bone metabolism and there are preliminary reports of its involvement in bone tumors and bone metastasis.

Modulating SARS-CoV-2 Spike Protein Reactivity through Moderate Electric Fields: A Pathway to Innovative Therapies.

In the quest for effective COVID-19 treatments and vaccines, traditional biochemical methods have been paramount, yet the challenge of accommodating diverse viral mutants persists. Recent simulations propose an innovative physical strategy involving an external electric field applied to the SARS-CoV-2 spike protein, demonstrating a reduced viral binding potential. However, limited empirical knowledge exists regarding the characteristics of the spike protein after E-field treatment.

Straightforward fabrication of electrochemical aptasensors with outstanding antifouling performance.

Self-assembled monolayers (SAMs) are popular tools for many different applications - SAMs of commercially available chemicals that convincingly inhibit unspecific binding for electrochemical sensors, however, have yet to be developed. While adsorption of foulants prohibits the reliable analysis of biological samples, unspecific binding of the analyte similarly impedes the investigation of binding characteristics from buffer solutions. In this communication, diglycolamine is introduced for the modification of electrodes with outstanding antifouling performance.

Deformability and collision-induced reorientation enhance cell topotaxis in dense microenvironments.

In vivo, cells navigate through complex environments filled with obstacles such as other cells and the extracellular matrix. Recently, the term "topotaxis" has been introduced for navigation along topographic cues such as obstacle density gradients. Experimental and mathematical efforts have analyzed topotaxis of single cells in pillared grids with pillar density gradients.

Mechanics of leukemic T-cell.

Cell mechanics is a factor that determines cell growth, migration, proliferation, or differentiation, as well as trafficking inside the cytoplasm and organization of organelles. Knowledge about cell mechanics is critical to gaining insight into these biological processes. Here, we used atomic force microscopy to examine the elasticity, an important parameter of cell mechanics, of non-adherent Jurkat leukemic T-cells in both interphase and mitotic phases.

Algorithms for Reconstruction of Impedance Spectra from Non-uniformly Sampled Step Responses.

Fast and reliable bioimpedimetric measurements are of growing importance in many practical applications. In this work we used a measurement method in time domain by processing the step response of the biological system under test. In order to decrease the data volume and computation time while retaining all relevant information the step response is sampled non-uniformly.

High-frequency Contactless Sensor for the Detection of Heparin-Induced Thrombocytopenia Antibodies via Platelet Aggregation.

Heparin-induced thrombocytopenia (HIT), a severe autoimmune disorder, occurs in patients undergoing heparin therapy. The presence of platelet-activating antibodies against platelet factor 4/Heparin in the blood confirms patients suffering from HIT. The most widely used methods for HIT diagnosis are immunoassays but the results only suit to rule out HIT as the assays provide only around 50% specificity.

Tailored Polyelectrolyte Multilayer Systems by Variation of Polyelectrolyte Composition and EDC/NHS Cross-Linking: Controlled Drug Release vs. Drug Reservoir Capabilities and Cellular Response for Improved Osseointegration.

Polyelectrolyte multilayers (PEM) are versatile tools used to investigate fundamental interactions between material-related parameters and the resulting performance in stem cell differentiation, respectively, in bone tissue engineering. In the present study, we investigate the suitability of PEMs with a varying collagen content for use as drug carriers for the human bone morphogenetic protein 2 (rhBMP-2). We use three different PEM systems consisting either of the positively charged poly-L-lysine or the glycoprotein collagen type I and the negatively charged glycosaminoglycan heparin.

Synthesis of Biocompatible Superparamagnetic Iron Oxide Nanoparticles (SPION) under Different Microfluidic Regimes.

Superparamagnetic iron oxide nanoparticles (SPION) have a great potential in both diagnostic and therapeutic applications as they provide contrast in magnetic resonance imaging techniques and allow magnetic hyperthermia and drug delivery. Though various types of SPION are commercially available, efforts to improve the quality of SPION are highly in demand. Here, we describe a strategy for optimization of SPION synthesis under microfluidics using the coprecipitation approach.

Breast cancer cell-based ELISA: a potential material for better detection of heparin-induced thrombocytopenia antibodies.

Heparin-induced thrombocytopenia (HIT) is caused by newly formed platelet-activating antibodies against complexes formed between platelet factor 4 (PF4) and heparin (H). HIT can result in life-threatening complications; thus, early detection of HIT antibodies is crucial for the treatment of the disease. The enzyme-linked immune absorbance assay (ELISA) for the identification of HIT antibodies is widely used in many laboratories, but in general, this test provides only ∼50% accuracy while other methods show multiple limitations.

Collagen-Based Osteogenic Nanocoating of Microrough Titanium Surfaces.

The aim of the present study was to develop a collagen/heparin-based multilayer coating on titanium surfaces for retarded release of recombinant human bone morphogenic protein 2 (rhBMP2) to enhance the osteogenic activity of implant surfaces. Polyelectrolyte multilayer (PEM) coatings were constructed on sandblasted/acid-etched surfaces of titanium discs using heparin and collagen. PEM films of ten double layers were produced and overlayed with 200 µL of a rhBMP2 solution containing 15 µg rhBMP2.

When Will Fondaparinux Induce Thrombocytopenia?

The pentasaccharide Fondaparinux, a synthetic selective factor Xa inhibitor, is one of the safest anticoagulants in the heparin family that is recommended as an alternative drug for patients with hypersensitivity to other drugs such as heparin-induced thrombocytopenia (HIT). However, some observations of Fondaparinux-induced thrombocytopenia (FIT) have been reported while others claimed that FIT does not occur in patients with fondaparinux therapy, indicating that the mechanism of FIT remains controversial. Here, we utilized different methodologies including dynamic light scattering, immunosorbent and platelet aggregation assays, confocal laser scanning microscopy, and flow cytometry to gain insights into FIT.

Tailored Polyelectrolyte Multilayer Systems by Variation of Polyelectrolyte Composition and EDC/NHS Cross-Linking: Physicochemical Characterization and In Vitro Evaluation.

The layer-by-layer (LbL) self-assembly technique is an effective method to immobilize components of the extracellular matrix (ECM) such as collagen and heparin onto, e.g., implant surfaces/medical devices with the aim of forming polyelectrolyte multilayers (PEMs).

FluidFM-Based Fabrication of Nanopatterns: Promising Surfaces for Platelet Storage Application.

Platelets are cell fragments from megakaryocytes devoid of the cell nucleus. They are highly sensitive and easily activated by nonphysiological surfaces. Activated platelets have an intrinsic mechanism to release various proteins that participate in multiple pathways, initiating the platelet activation cascade.

Development of a system of heparin multilayers on titanium surfaces for dual growth factor release.

The aim of the present study was to establish a modular platform of poly-L-lysine-heparin (PLL-Hep) polyelectrolyte multilayer (PEM) coatings on titanium surfaces for dual growth factor delivery of recombinant human bone morphogenic protein 2 (rhBMP2) and recombinant human vascular endothelial growth factor 165 (rhVEGF165) in clinically relevant quantities. Release characteristics for both growth factors differed significantly depending on film architecture. rhBMP2 induced activation of alkaline phosphatase in C2C12 cells and proliferation of human mesenchymal stem cells (hMSCs).

Integration of Biofunctional Molecules into 3D-Printed Polymeric Micro-/Nanostructures.

Three-dimensional printing at the micro-/nanoscale represents a new challenge in research and development to achieve direct printing down to nanometre-sized objects. Here, FluidFM, a combination of microfluidics with atomic force microscopy, offers attractive options to fabricate hierarchical polymer structures at different scales. However, little is known about the effect of the substrate on the printed structures and the integration of (bio)functional groups into the polymer inks.