Selected publications
Maasi: A 3D printed spin coater with touchscreen
Spin coaters are widely used to apply thin films of a material uniformly over a flat substrate. Despite the simplicity of this technique the entry price for such machines might be prohibitive, ranging from few hundreds to thousands of Euros. Here we present Maasi, an affordable alternative that is easy to build and has all functional key features to be used in a wide range of applications. Our design has a price of less than hundred Euros and an assembly time of only two hours. One of the key design principles was to use only 3D printed parts in combination with affordable Commercial Off-The-Shelf (COTS) components [1] . Reducing the complexity we use an electronic speed controller (ESC) with telemetry, to eliminate the need for a rotor position sensor [2]. A touchscreen further improves its usability, thus setting a perfect startpoint for the design of other affordable lab tools. The Maasi project includes different 3D printable substrate holders allowing treatment of formats up to 80 mm in diameter. We furthermore validate the Maasi spin coater by measuring its speed accuracy and performance for coating polydimethylsiloxane… Read More..
Nanoconfinement of Microvilli Alters Gene Expression and Boosts T cell Activation
T cells sense and respond to their local environment at the nanoscale by forming small actin-rich protrusions, called microvilli, which play critical roles in signaling and antigen recognition, particularly at the interface with the antigen presenting cells. However, the mechanism by which microvilli contribute to cell signaling and activation is largely unknown. Here, we present a tunable engineered system that promotes microvilli formation and T cell signaling via physical stimuli. We discovered that nanoporous surfaces favored microvilli formation and markedly altered gene expression in T cells and promoted their activation. Mechanistically, confinement of microvilli inside of nanopores leads to size-dependent sorting of membrane-anchored proteins, specifically segregating CD45 phosphatases and T cell receptors (TCR) from the tip of the protrusions when microvilli are confined in 200-nm pores but not in 400-nm pores. Consequently, formation of TCR nanoclustered hotspots within 200-nm pores allows sustained and augmented signaling that prompts T cell activation even in the absence of TCR agonists. The synergistic combination of mechanical and biochemical signals on porous surfaces presents a straightforward strategy to investigate the role of microvilli in T cell signaling as well as… Read More..
Temporal Analysis of T cell Receptor-Imposed Forces via Quantitative Single Molecule FRET Measurements
Mechanical forces acting on ligand-engaged T-cell receptors (TCRs) have previously been implicated in T-cell antigen recognition, yet their magnitude, spread, and temporal behavior are still poorly defined. We here report a FRET-based sensor equipped either with a TCR-reactive single chain antibody fragment or peptide-loaded MHC, the physiological TCR-ligand. The sensor was tethered to planar glass-supported lipid bilayers (SLBs) and informed most directly on the magnitude and kinetics of TCR-imposed forces at the single molecule level. When confronting T-cells with gel-phase SLBs we observed both prior and upon T-cell activation a single, well-resolvable force-peak of approximately 5 pN and force loading rates on the TCR of 1.5 pN per second. When facing fluid-phase SLBs instead, T-cells still exerted tensile forces yet of threefold reduced magnitude and only prior to but not upon activation. Read More..
The solid tumor microenvironment-Breaking the barrier for T cells: How the solid tumor microenvironment influences T cell
The tumor microenvironment (TME) plays a pivotal role in the behavior and development of solid tumors as well as shaping the immune response against them. As the tumor cells proliferate, the space they occupy and their physical interactions with the surrounding tissue increases. The growing tumor tissue becomes a complex dynamic structure, containing connective tissue, vascular structures, and extracellular matrix (ECM) that facilitates stimulation, oxygenation, and nutrition, necessary for its fast growth. Mechanical cues such as stiffness, solid stress, interstitial fluid pressure (IFP), matrix density, and microarchitecture influence cellular functions and ultimately tumor progression and metastasis. In this fight, our body is equipped with T cells as its spearhead against tumors. However, the altered biochemical and mechanical environment of the tumor niche affects T cell efficacy and leads to their exhaustion. Understanding the mechanobiological properties of the TME and their effects on T cells is key for developing novel adoptive tumor immunotherapies. Read More..