Biology subjects

Dufva, M.

Publications and source records attributed to Dufva, M..

5 recordsLinked to original sources

bioRxiv2026

Embedded Printing-Derived Pyrolytic Carbon Electrodes with Graphene-like Features for Neural Stem Cell Differentiation and Dopamine Sensing

Carbon is a versatile electrode material that is used in applications ranging from electrical energy storage and electrosynthesis to CO2 conversion, H2 production, and biosensing. The development of pyrolytic carbon electrodes derived from lithographically patterned photoresist structures has expanded the possibilities for creating diverse 2D and 3D electrode designs. In this paper, we present disc-shaped SU-8-derived pyrolytic carbon scaffold electrodes with an open hexagonal honeycomb lattice. The scaffolds were fabricated, using embedded 3D printing within a shear-thinning support bath composed of fused silica nanoparticles (7% w/v) in mineral oil. The rheological properties of the support bath were optimized to enable the printing of low-viscosity materials like SU-8, which would otherwise lack structural integrity in standard extrusion-based 3D printing. The SU-8 scaffolds were then pyrolyzed and characterized using SEM, Raman spectroscopy, Energy Dispersive X-ray, X-ray Photoelectron Spectrometry, and Transmission Electron Microscopy, which revealed graphene-like 'microflowers' on its surface. Electrochemical analysis demonstrated excellent electrochemical properties. The functionality of the scaffold electrodes was validated by differentiation of human neural stem cells into dopaminergic neurons on the scaffold surface, followed by real-time detection of dopamine exocytosis upon cell depolarization.

bioengineering↗

bioRxiv2025

ChipNMR: Hyperpolarized NMR for non-invasive metabolic flux analysis in perfused microfluidic chips

Dissolution dynamic nuclear polarization NMR Spectroscopy (dDNP-NMR) has become a transformative tool for metabolic studies by significantly enhancing signal sensitivity more than three orders of magnitude compared to traditional NMR. However, NMR detection probes are optimized for round narrow glass tubes typically 5 mm in diameter, which impose constraints on their utility for metabolic studies of adhernt cells. Here, we present a novel NMR probe head integrated with a custom microfluidic chip that facilitates real-time monitoring of hyperpolarized substrate conversion from adhernt cells. This system enables metabolic flux analysis in a controlled, in vitro environment, as demonstrated by tracking the conversion of [1-13C] pyruvate to [1-13C] lactate in HeLa cells over 48 hours. To the best of our knowledge, this is the first demonstration of cell metabolism from an adhering monolayer of mammalian cells in combination with hyperpolarized NMR. The custom microfluidic chip design is modular and adaptable allowing expansion to dual-chamber chips, demonstrating its potential in applications for more complex cellular environments, such as Organ-on-a-Chip systems.

biochemistry↗

bioRxiv2024

Tumor Spheroid Uptake of Fluorescent Nanodiamonds is Limited by Mass Density: a 4D Light-Sheet Assay

Fluorescent nanodiamonds (FNDs) with nitrogen-vacancy centers are promising candidates for long-term biolabeling and biosensing applications due to their biocompatibility and unique optomagnetic properties. The employment of nanomaterials in cancer therapy and diagnostics, requires a deep understanding of how nanoparticles (NPs) interact with the three-dimensional (3D) tumor environment. We developed a novel approach, the "Tumor-in-a-Tube" platform, using 4D light-sheet microscopy to explore the spatio-temporal dynamics of FNDs with 3D tumor spheroids. By monitoring the real-time NP sedimentation, spheroid penetration, and cellular uptake of FNDs and polystyrene nanoparticles (PNPs), we marked the impact of NP mass density on their spheroid interaction. Unlike PNPs, higher-density FNDs underwent rapid sedimentation, which minimized their effective concentration and hindered the FND - spheroid interactions. This results in constrained intratumoral accumulation, and size-independent uptake and penetration. Longer FND effective-exposure-time promotes size-dependent cell uptake, verified by FND treatment on 2D monolayers. Nonetheless, FNDs exhibited good biocompatibility and long-term spheroid labeling, allowing for cell isolation from different spheroid layers. Our results suggest the need for NP effective-exposure-time calibration in comparative NP assays, in 3D static models. Overall, our platform provides a valuable tool for bridging the gap between 2D and 3D static models in NP assessment, drug delivery, toxicology profiling and translational research.

biophysics↗

bioRxiv2022

Quantitative Evaluation of the Cellular Uptake of Nanodiamonds by Monocytes and Macrophages

Nanodiamonds (NDs) with NV- defect centers are great probes for bionanotechnology applications, with potential to act as biomarkers for cell differentiation. To explore this concept, uptake of NDs (~120nm) by THP-1 monocytes and monocyte-derived M0-macrophages is studied. The time course analysis of ND uptake by monocytes confirms differing ND-cell interactions and a positive time-dependence. No effect on cell viability, proliferation and differentiation potential into macrophages is observed, while cells saturated with NDs, unload the NDs completely by 25 cell divisions and subsequently take up a second dose effectively. ND uptake variations by THP-1 cells at early exposure-times indicate differing phagocytic capability. The cell fraction that exhibits relatively enhanced ND uptake is associated to a macrophage phenotype which derives from spontaneous monocyte differentiation. In accordance, chemical-differentiation of the THP-1 cells into M0-macrophages triggers increased and homogeneous ND uptake, depleting the fraction of cells that were non-responsive to NDs. These observations verify that ND uptake allows for distinction between the two cell subtypes based on phagocytic capacity. Overall, NDs demonstrate effective cell labeling of monocytes and macrophages, and are promising candidates for tracking biological processes that involve cell differentiation.

cell biology↗

bioRxiv2018

Controlling fluid flow to improve cell seeding uniformity

Standard methods for seeding monolayer cell cultures in a multiwell plate or dish do not uniformly distribute cells on the surface. With traditional methods, users find aggregation around the circumference, in the centre, or a combination of the two. This variation is introduced due to the macro scale flow of the cell seeding suspension, and movement of the dish before cells can settle and attach to the surface. Reproducibility between labs, users, and experiments is hampered by this variability in cell seeding. We present a simple method for uniform and user-independent cell seeding using an easily produced uniform cell seeder (UCS) device. This allows precise control of cell density in a reproducible manner. By containing the cell seeding suspension in a defined volume above the culture surface with the UCS, fluctuations in cell density are minimised. Seeding accuracy, as defined by the actual cell density versus the target seeding density is improved dramatically across users with various levels of expertise. We go on to demonstrate the impact of local variation in cell density on the lineage commitment of human embryonic stem cells (hESCs) towards pancreatic endoderm (PE). Variations in the differentiation profile of cells across a culture well closely mirror variations in cell density introduced by seeding method - with the UCS correcting variations in differentiation efficiency. The UCS device provides a simple and reproducible method for uniform seeding across multiple culture systems.

cell biology↗