@article{21231,
  abstract     = {To assess cell migration in complex spatial environments, microfabricated chips, such as mazes and pillar forests, are routinely used to impose spatial and mechanical constraints, and cell trajectories are followed within these structures by advanced imaging techniques. In systems mechanobiology, computational models serve as essential tools to uncover how physical geometry influences intracellular dynamics; however, decoding such complex behaviors requires advanced inference techniques. Here, we integrated experimental observations of dendritic cell migration in a geometrically constrained microenvironment into a Cellular Potts model. We demonstrated that these spatial constraints modulate the motility dynamics, including speed and directional changes. We show that classical summary statistics, such as mean squared displacement and turning angle distributions, can resolve key mechanistic features but fail to extract richer spatiotemporal patterns, limiting accurate parameter inference. To solve this, we applied neural posterior estimation with in-the-loop learning of summary features. This learned summary representation of the data enables robust and flexible parameter inference, providing a data-driven framework for model calibration and advancing quantitative analysis of cell migration in structured microenvironments.},
  author       = {Arruda, Jonas and Alamoudi, Emad and Mueller, Robert and Vaisband, Marc and Molkenbur, Ronja and Merrin, Jack and Kiermaier, Eva and Hasenauer, Jan},
  issn         = {2056-7189},
  journal      = {npj Systems Biology and Applications},
  publisher    = {Springer Nature},
  title        = {{Simulation-based inference of cell migration dynamics in complex spatial environments}},
  doi          = {10.1038/s41540-026-00648-9},
  volume       = {12},
  year         = {2026},
}

@article{20295,
  abstract     = {Scanning Kelvin probe microscopy (SKPM) is a powerful technique for macroscopic imaging of the electrostatic potential above a surface. Though most often used to image work-function variations of conductive surfaces, it can also be used to probe the surface charge on insulating surfaces. In both cases, relating the measured potential to the underlying signal is non-trivial. Here, general relationships are derived between the measured SKPM voltage and the underlying source, revealing either can be cast as a convolution with an appropriately scaled point spread function (PSF). For charge that exists on a thin insulating layer above a conductor, the PSF has the same shape as what would occur from a work-function variation alone, differing by a simple scaling factor. This relationship is confirmed by: (1) backing it out from finite-element simulations of work-function and charge signals, and (2) experimentally comparing the measured PSF from a small work-function target to that from a small charge spot. This scaling factor is further validated by comparing SKPM charge measurements with Faraday cup measurements for highly charged samples from contact-charging experiments. These results highlight a heretofore unappreciated connection between SKPM voltage and charge signals, offering a rigorous recipe to extract either from experimental data.},
  author       = {Lenton, Isaac C and Pertl, Felix and Shafeek, Lubuna B and Waitukaitis, Scott R},
  issn         = {2196-7350},
  journal      = {Advanced Materials Interfaces},
  number       = {19},
  publisher    = {Wiley},
  title        = {{A duality between surface charge and work function in scanning Kelvin probe microscopy}},
  doi          = {10.1002/admi.202500521},
  volume       = {12},
  year         = {2025},
}

@article{19663,
  abstract     = {The centrosome is a microtubule orchestrator, nucleating and anchoring microtubules that grow radially and exert forces on cargos. At the same time, mechanical stresses from the microenvironment and cellular shape changes compress and bend microtubules. Yet, centrosomes are membraneless organelles, raising the question of how centrosomes withstand mechanical forces. Here, we discover that centrosomes can deform and even fracture. We reveal that centrosomes experience deformations during navigational pathfinding within motile cells. Coherence of the centrosome is maintained by Dyrk3 and cNAP1, preventing fracturing by forces. While cells can compensate for the depletion of centriolar-based centrosomes, the fracturing of centrosomes impedes cellular function by generating coexisting microtubule organizing centers that compete during path navigation and thereby cause cellular entanglement in the microenvironment. Our findings show that cells actively maintain the integrity of the centrosome to withstand mechanical forces. These results suggest that centrosome stability preservation is fundamental, given that almost all cells in multicellular organisms experience forces.},
  author       = {Schmitt, Madeleine T. and Kroll, Janina and Ruiz-Fernandez, Mauricio J.A. and Hauschild, Robert and Ghosh, Shaunak and Kameritsch, Petra and Merrin, Jack and Schmid, Johanna and Stefanowski, Kasia and Thomae, Andreas W. and Cheng, Jingyuan and Öztan, Gamze Naz and Konopka, Peter and Ortega, Germán Camargo and Penz, Thomas and Bach, Luisa and Baumjohann, Dirk and Bock, Christoph and Straub, Tobias and Meissner, Felix and Kiermaier, Eva and Renkawitz, Jörg},
  issn         = {2375-2548},
  journal      = {Science Advances},
  number       = {17},
  publisher    = {AAAS},
  title        = {{Protecting centrosomes from fracturing enables efficient cell navigation}},
  doi          = {10.1126/sciadv.adx4047},
  volume       = {11},
  year         = {2025},
}

@article{20859,
  abstract     = {Effective immune responses rely on the efficient migration of leukocytes. Yet, how temperature regulates migration dynamics at the single-cell level has remained poorly understood. Using zebrafish embryos and mouse tissue explants, we found that temperature positively regulates leukocyte migration speed, exploration, and arrival frequencies to wounds and lymph vessels. Complementary 2D and 3D cultures revealed that this thermokinetic control of cell migration is conserved across immune cell types, independently of the 3D tissue environment. By applying precise (sub-)cellular temperature modulation, we identified a rapid and reversible thermo-response that depends on myosin II activity. Small physiological increases in temperature (1°C –2°C), as present during fever-like conditions, profoundly increased immune responses by accelerating arrival times at lymphatic vessels and tissue wounds. These findings identify myosin-II-dependent actomyosin contractility as a critical mechanical structure regulating single-cell thermo-adaptability, with physiological implications for tuning the speed of immune responses in vivo.},
  author       = {Company-Garrido, Iván and Zurita Carpio, Alberto and Colomer-Rosell, Mariona and Ciraulo, Bernard and Molkenbur, Ronja and Lanzerstorfer, Peter and Pezzano, Fabio and Agazzi, Costanza and Hauschild, Robert and Jain, Saumey and Jacques, Jeroen M. and Venturini, Valeria and Knapp, Christian and Xie, Yufei and Merrin, Jack and Weghuber, Julian and Schaaf, Marcel and Quidant, Romain and Kiermaier, Eva and Ortega Arroyo, Jaime and Ruprecht, Verena and Wieser, Stefan},
  issn         = {1878-1551},
  journal      = {Developmental Cell},
  publisher    = {Elsevier},
  title        = {{Myosin II regulates cellular thermo-adaptability and the efficiency of immune responses}},
  doi          = {10.1016/j.devcel.2025.10.006},
  year         = {2025},
}

@unpublished{21427,
  abstract     = {While tumor malignancy has been extensively studied under the prism of genetic and epigenetic heterogeneity, tumor cell states also critically depend on reciprocal interactions with the microenvironment. This raises the hitherto untested possibility that heterogeneity of the untransformed tumor stroma can actively fuel malignant progression. As biological heterogeneity is inherently difficult to control, we adopted a reductionist approach and let tumor cells invade micro-engineered environments harboring obstacles with precision-controlled geometry. We find that not only the presence of obstacles, but more surprisingly their spatial disorder, causes a drastic shift from a collective to a single-cell mode of invasion – comparable in strength to cadherin loss. Combining live-imaging and perturbation experiments with minimal biophysical modeling, we demonstrate that cell detachments result both from local geometrical constraints and a global integration of spatial disorder over time. We show that different types of microenvironments map onto different universality classes of invasion dynamics - homogeneous substrates follow Kardar–Parisi–Zhang (KPZ) scaling, while disordered ones exhibit exponents consistent with KPZ with quenched disorder (KPZq). Our findings highlight generic physical principles for how the mode of cancer cell invasion depends on environmental heterogeneity, with potential implications to understand tumor evolution in vivo.},
  author       = {Dunajova, Zuzana and Tasciyan, Saren and Majek, Juraj and Merrin, Jack and Sahai, Erik and Sixt, Michael K and Hannezo, Edouard B},
  publisher    = {bioRxiv},
  title        = {{Substrate heterogeneity promotes cancer cell dissemination through interface roughening}},
  doi          = {10.1101/2025.05.20.655037},
  year         = {2025},
}

@article{20082,
  abstract     = {Efficient immune responses rely on the capacity of leukocytes to traverse diverse and complex tissues. To meet such changing environmental conditions, leukocytes usually adopt an ameboid configuration, using their forward-positioned nucleus as a probe to identify and follow the path of least resistance among pre-existing pores. We show that, in dense environments where even the largest pores preclude free passage, leukocytes position their nucleus behind the centrosome and organelles. The local compression imposed on the cell body by its surroundings triggers assembly of a central F-actin pool, located between cell front and nucleus. Central actin pushes outward to transiently dilate a path for organelles and nucleus. Pools of central and front actin are tightly coupled and experimental depletion of the central pool enhances actin accumulation and protrusion formation at the cell front. Although this shifted balance speeds up cells in permissive environments, migration in restrictive environments is impaired, as the unleashed leading edge dissociates from the trapped cell body. Our findings establish an actin regulatory loop that balances path dilation with advancement of the leading edge to maintain cellular coherence.},
  author       = {Dos Reis Rodrigues, Patricia and Avellaneda Sarrió, Mario and Canigova, Nikola and Gärtner, Florian R and Vaahtomeri, Kari and Riedl, Michael and De Vries, Ingrid and Merrin, Jack and Hauschild, Robert and Fukui, Yoshinori and Juanes Garcia, Alba and Sixt, Michael K},
  issn         = {1529-2916},
  journal      = {Nature Immunology},
  pages        = {1258–1266},
  publisher    = {Springer Nature},
  title        = {{Migrating immune cells globally coordinate protrusive forces}},
  doi          = {10.1038/s41590-025-02211-w},
  volume       = {26},
  year         = {2025},
}

@article{18807,
  abstract     = {Developing tissues interpret dynamic changes in morphogen activity to generate cell type diversity. To quantitatively study bone morphogenetic protein (BMP) signaling dynamics in the mouse neural tube, we developed an embryonic stem cell differentiation system tailored for growing tissues. Differentiating cells form striking self-organized patterns of dorsal neural tube cell types driven by sequential phases of BMP signaling that are observed both in vitro and in vivo. Data-driven biophysical modeling showed that these dynamics result from coupling fast negative feedback with slow positive regulation of signaling by the specification of an endogenous BMP source. Thus, in contrast to relays that propagate morphogen signaling in space, we identify a BMP signaling relay that operates in time. This mechanism allows for a rapid initial concentration-sensitive response that is robustly terminated, thereby regulating balanced sequential cell type generation. Our study provides an experimental and theoretical framework to understand how signaling dynamics are exploited in developing tissues.},
  author       = {Rus, Stefanie and Brückner, David and Minchington, Thomas and Greunz, Martina and Merrin, Jack and Hannezo, Edouard B and Kicheva, Anna},
  issn         = {1534-5807},
  journal      = {Developmental Cell},
  number       = {4},
  pages        = {567--580},
  publisher    = {Elsevier},
  title        = {{Self-organized pattern formation in the developing mouse neural tube by a temporal relay of BMP signaling}},
  doi          = {10.1016/j.devcel.2024.10.024},
  volume       = {60},
  year         = {2025},
}

@article{14795,
  abstract     = {Metazoan development relies on the formation and remodeling of cell-cell contacts. Dynamic reorganization of adhesion receptors and the actomyosin cell cortex in space and time plays a central role in cell-cell contact formation and maturation. Nevertheless, how this process is mechanistically achieved when new contacts are formed remains unclear. Here, by building a biomimetic assay composed of progenitor cells adhering to supported lipid bilayers functionalized with E-cadherin ectodomains, we show that cortical F-actin flows, driven by the depletion of myosin-2 at the cell contact center, mediate the dynamic reorganization of adhesion receptors and cell cortex at the contact. E-cadherin-dependent downregulation of the small GTPase RhoA at the forming contact leads to both a depletion of myosin-2 and a decrease of F-actin at the contact center. At the contact rim, in contrast, myosin-2 becomes enriched by the retraction of bleb-like protrusions, resulting in a cortical tension gradient from the contact rim to its center. This tension gradient, in turn, triggers centrifugal F-actin flows, leading to further accumulation of F-actin at the contact rim and the progressive redistribution of E-cadherin from the contact center to the rim. Eventually, this combination of actomyosin downregulation and flows at the contact determines the characteristic molecular organization, with E-cadherin and F-actin accumulating at the contact rim, where they are needed to mechanically link the contractile cortices of the adhering cells.},
  author       = {Arslan, Feyza N and Hannezo, Edouard B and Merrin, Jack and Loose, Martin and Heisenberg, Carl-Philipp J},
  issn         = {1879-0445},
  journal      = {Current Biology},
  number       = {1},
  pages        = {171--182.e8},
  publisher    = {Elsevier},
  title        = {{Adhesion-induced cortical flows pattern E-cadherin-mediated cell contacts}},
  doi          = {10.1016/j.cub.2023.11.067},
  volume       = {34},
  year         = {2024},
}

@article{14846,
  abstract     = {Contraction and flow of the actin cell cortex have emerged as a common principle by which cells reorganize their cytoplasm and take shape. However, how these cortical flows interact with adjacent cytoplasmic components, changing their form and localization, and how this affects cytoplasmic organization and cell shape remains unclear. Here we show that in ascidian oocytes, the cooperative activities of cortical actomyosin flows and deformation of the adjacent mitochondria-rich myoplasm drive oocyte cytoplasmic reorganization and shape changes following fertilization. We show that vegetal-directed cortical actomyosin flows, established upon oocyte fertilization, lead to both the accumulation of cortical actin at the vegetal pole of the zygote and compression and local buckling of the adjacent elastic solid-like myoplasm layer due to friction forces generated at their interface. Once cortical flows have ceased, the multiple myoplasm buckles resolve into one larger buckle, which again drives the formation of the contraction pole—a protuberance of the zygote’s vegetal pole where maternal mRNAs accumulate. Thus, our findings reveal a mechanism where cortical actomyosin network flows determine cytoplasmic reorganization and cell shape by deforming adjacent cytoplasmic components through friction forces.},
  author       = {Caballero Mancebo, Silvia and Shinde, Rushikesh and Bolger-Munro, Madison and Peruzzo, Matilda and Szep, Gregory and Steccari, Irene and Labrousse Arias, David and Zheden, Vanessa and Merrin, Jack and Callan-Jones, Andrew and Voituriez, Raphaël and Heisenberg, Carl-Philipp J},
  issn         = {1745-2481},
  journal      = {Nature Physics},
  pages        = {310--321},
  publisher    = {Springer Nature},
  title        = {{Friction forces determine cytoplasmic reorganization and shape changes of ascidian oocytes upon fertilization}},
  doi          = {10.1038/s41567-023-02302-1},
  volume       = {20},
  year         = {2024},
}

@article{15018,
  abstract     = {The epitaxial growth of a strained Ge layer, which is a promising candidate for the channel material of a hole spin qubit, has been demonstrated on 300 mm Si wafers using commercially available Si0.3Ge0.7 strain relaxed buffer (SRB) layers. The assessment of the layer and the interface qualities for a buried strained Ge layer embedded in Si0.3Ge0.7 layers is reported. The XRD reciprocal space mapping confirmed that the reduction of the growth temperature enables the 2-dimensional growth of the Ge layer fully strained with respect to the Si0.3Ge0.7. Nevertheless, dislocations at the top and/or bottom interface of the Ge layer were observed by means of electron channeling contrast imaging, suggesting the importance of the careful dislocation assessment. The interface abruptness does not depend on the selection of the precursor gases, but it is strongly influenced by the growth temperature which affects the coverage of the surface H-passivation. The mobility of 2.7 × 105 cm2/Vs is promising, while the low percolation density of 3 × 1010 /cm2 measured with a Hall-bar device at 7 K illustrates the high quality of the heterostructure thanks to the high Si0.3Ge0.7 SRB quality.},
  author       = {Shimura, Yosuke and Godfrin, Clement and Hikavyy, Andriy and Li, Roy and Aguilera Servin, Juan L and Katsaros, Georgios and Favia, Paola and Han, Han and Wan, Danny and de Greve, Kristiaan and Loo, Roger},
  issn         = {1369-8001},
  journal      = {Materials Science in Semiconductor Processing},
  keywords     = {Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science},
  number       = {5},
  publisher    = {Elsevier},
  title        = {{Compressively strained epitaxial Ge layers for quantum computing applications}},
  doi          = {10.1016/j.mssp.2024.108231},
  volume       = {174},
  year         = {2024},
}

@article{17373,
  abstract     = {Scanning Kelvin probe microscopy (SKPM) is a powerful technique for investigating the electrostatic properties of material surfaces, enabling the imaging of variations in work function, topology, surface charge density, or combinations thereof. Regardless of the underlying signal source, SKPM results in a voltage image, which is spatially distorted due to the finite size of the probe, long-range electrostatic interactions, mechanical and electrical noise, and the finite response time of the electronics. In order to recover the underlying signal, it is necessary to deconvolve the measurement with an appropriate point spread function (PSF) that accounts the aforementioned distortions, but determining this PSF is difficult. Here, we describe how such PSFs can be determined experimentally and show how they can be used to recover the underlying information of interest. We first consider the physical principles that enable SKPM and discuss how these affect the system PSF. We then show how one can experimentally measure PSFs by looking at well-defined features, and that these compare well to simulated PSFs, provided scans are performed extremely slowly and carefully. Next, we work at realistic scan speeds and show that the idealized PSFs fail to capture temporal distortions in the scan direction. While simulating PSFs for these situations would be quite challenging, we show that measuring PSFs with similar scan conditions works well. Our approach clarifies the basic principles and inherent challenges to SKPM measurements and gives practical methods to improve results.},
  author       = {Lenton, Isaac C and Pertl, Felix and Shafeek, Lubuna B and Waitukaitis, Scott R},
  issn         = {1089-7550},
  journal      = {Journal of Applied Physics},
  number       = {4},
  publisher    = {AIP Publishing},
  title        = {{Beyond the blur: Using experimentally determined point spread functions to improve scanning Kelvin probe imaging}},
  doi          = {10.1063/5.0215151},
  volume       = {136},
  year         = {2024},
}

@article{17479,
  abstract     = {Phonon polaritons (PhPs), light coupled to lattice vibrations, in the highly anisotropic polar layered material molybdenum trioxide (α-MoO3) are currently the focus of intense research efforts due to their extreme subwavelength field confinement, directional propagation, and unprecedented low losses. Nevertheless, prior research has primarily concentrated on exploiting the squeezing and steering capabilities of α-MoO3 PhPs, without inquiring much into the dominant microscopic mechanism that determines their long lifetimes, which is key for their implementation in nanophotonic applications. This study delves into the fundamental processes that govern PhP damping in α-MoO3 by combining ab initio calculations with scattering-type scanning near-field optical microscopy (s-SNOM) and Fourier transform infrared (FTIR) spectroscopy measurements across a broad temperature range (8–300 K). The remarkable agreement between our theoretical predictions and experimental observations allows us to identify third-order anharmonic phonon–phonon scattering as the main damping mechanism of α-MoO3 PhPs. These findings shed light on the fundamental limits of low-loss PhPs, which is a crucial factor for assessing their implementation into nanophotonic devices.},
  author       = {Taboada-Gutiérrez, Javier and Zhou, Yixi and Tresguerres-Mata, Ana I.F. and Lanza, Christian and Martínez-Suárez, Abel and Álvarez-Pérez, Gonzalo and Duan, Jiahua and Martín, José Ignacio and Vélez, María and Prieto Gonzalez, Ivan and Bercher, Adrien and Teyssier, Jérémie and Errea, Ion and Nikitin, Alexey Y. and Martín-Sánchez, Javier and Kuzmenko, Alexey B. and Alonso-González, Pablo},
  issn         = {2330-4022},
  journal      = {ACS Photonics},
  number       = {9},
  pages        = {3570--3577},
  publisher    = {American Chemical Society},
  title        = {{Unveiling the mechanism of phonon-polariton damping in α‑MoO3}},
  doi          = {10.1021/acsphotonics.4c00485},
  volume       = {11},
  year         = {2024},
}

@article{18601,
  abstract     = {Geometrically controlled stem cell differentiation promotes reproducible pattern formation. Here, we present a protocol to fabricate elastomeric stencils for patterned stem cell differentiation. We describe procedures for using photolithography to produce molds, followed by molding polydimethylsiloxane (PDMS) to obtain stencils with through holes. We then provide instructions for culturing cells on stencils and, finally, removing stencils to allow colony growth and cell migration. This approach yields reproducible two-dimensional organoids tailored for quantitative studies of growth and pattern formation.
For complete details on the use and execution of this protocol, please refer to Lehr et al.1},
  author       = {Rus, Stefanie and Merrin, Jack and Kulig, Monika Aleksandra and Minchington, Thomas and Kicheva, Anna},
  issn         = {2666-1667},
  journal      = {STAR Protocols},
  number       = {4},
  publisher    = {Elsevier},
  title        = {{Protocol for fabricating elastomeric stencils for patterned stem cell differentiation}},
  doi          = {10.1016/j.xpro.2024.103187},
  volume       = {5},
  year         = {2024},
}

@article{14361,
  abstract     = {Whether one considers swarming insects, flocking birds, or bacterial colonies, collective motion arises from the coordination of individuals and entails the adjustment of their respective velocities. In particular, in close confinements, such as those encountered by dense cell populations during development or regeneration, collective migration can only arise coordinately. Yet, how individuals unify their velocities is often not understood. Focusing on a finite number of cells in circular confinements, we identify waves of polymerizing actin that function as a pacemaker governing the speed of individual cells. We show that the onset of collective motion coincides with the synchronization of the wave nucleation frequencies across the population. Employing a simpler and more readily accessible mechanical model system of active spheres, we identify the synchronization of the individuals’ internal oscillators as one of the essential requirements to reach the corresponding collective state. The mechanical ‘toy’ experiment illustrates that the global synchronous state is achieved by nearest neighbor coupling. We suggest by analogy that local coupling and the synchronization of actin waves are essential for the emergent, self-organized motion of cell collectives.},
  author       = {Riedl, Michael and Mayer, Isabelle D and Merrin, Jack and Sixt, Michael K and Hof, Björn},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Synchronization in collectively moving inanimate and living active matter}},
  doi          = {10.1038/s41467-023-41432-1},
  volume       = {14},
  year         = {2023},
}

@inbook{13052,
  abstract     = {Imaging of the immunological synapse (IS) between dendritic cells (DCs) and T cells in suspension is hampered by suboptimal alignment of cell-cell contacts along the vertical imaging plane. This requires optical sectioning that often results in unsatisfactory resolution in time and space. Here, we present a workflow where DCs and T cells are confined between a layer of glass and polydimethylsiloxane (PDMS) that orients the cells along one, horizontal imaging plane, allowing for fast en-face-imaging of the DC-T cell IS.},
  author       = {Leithner, Alexander F and Merrin, Jack and Sixt, Michael K},
  booktitle    = {The Immune Synapse},
  editor       = {Baldari, Cosima and Dustin, Michael},
  isbn         = {9781071631348},
  issn         = {1940-6029},
  pages        = {137--147},
  publisher    = {Springer Nature},
  title        = {{En-Face Imaging of T Cell-Dendritic Cell Immunological Synapses}},
  doi          = {10.1007/978-1-0716-3135-5_9},
  volume       = {2654},
  year         = {2023},
}

@article{13342,
  abstract     = {Motile cells moving in multicellular organisms encounter microenvironments of locally heterogeneous mechanochemical composition. Individual compositional parameters like chemotactic signals, adhesiveness, and pore sizes are well known to be sensed by motile cells, providing individual guidance cues for cellular pathfinding. However, motile cells encounter diverse mechanochemical signals at the same time, raising the question of how cells respond to locally diverse and potentially competing signals on their migration routes. Here, we reveal that motile amoeboid cells require nuclear repositioning, termed nucleokinesis, for adaptive pathfinding in heterogeneous mechanochemical microenvironments. Using mammalian immune cells and the amoeba<jats:italic>Dictyostelium discoideum</jats:italic>, we discover that frequent, rapid and long-distance nucleokinesis is a basic component of amoeboid pathfinding, enabling cells to reorientate quickly between locally competing cues. Amoeboid nucleokinesis comprises a two-step cell polarity switch and is driven by myosin II-forces, sliding the nucleus from a ‘losing’ to the ‘winning’ leading edge to re-adjust the nuclear to the cellular path. Impaired nucleokinesis distorts fast path adaptions and causes cellular arrest in the microenvironment. Our findings establish that nucleokinesis is required for amoeboid cell navigation. Given that motile single-cell amoebae, many immune cells, and some cancer cells utilize an amoeboid migration strategy, these results suggest that amoeboid nucleokinesis underlies cellular navigation during unicellular biology, immunity, and disease.},
  author       = {Kroll, Janina and Hauschild, Robert and Kuznetcov, Arthur and Stefanowski, Kasia and Hermann, Monika D. and Merrin, Jack and Shafeek, Lubuna B and Müller-Taubenberger, Annette and Renkawitz, Jörg},
  issn         = {1460-2075},
  journal      = {EMBO Journal},
  publisher    = {Embo Press},
  title        = {{Adaptive pathfinding by nucleokinesis during amoeboid migration}},
  doi          = {10.15252/embj.2023114557},
  year         = {2023},
}

@article{14274,
  abstract     = {Immune responses rely on the rapid and coordinated migration of leukocytes. Whereas it is well established that single-cell migration is often guided by gradients of chemokines and other chemoattractants, it remains poorly understood how these gradients are generated, maintained, and modulated. By combining experimental data with theory on leukocyte chemotaxis guided by the G protein–coupled receptor (GPCR) CCR7, we demonstrate that in addition to its role as the sensory receptor that steers migration, CCR7 also acts as a generator and a modulator of chemotactic gradients. Upon exposure to the CCR7 ligand CCL19, dendritic cells (DCs) effectively internalize the receptor and ligand as part of the canonical GPCR desensitization response. We show that CCR7 internalization also acts as an effective sink for the chemoattractant, dynamically shaping the spatiotemporal distribution of the chemokine. This mechanism drives complex collective migration patterns, enabling DCs to create or sharpen chemotactic gradients. We further show that these self-generated gradients can sustain the long-range guidance of DCs, adapt collective migration patterns to the size and geometry of the environment, and provide a guidance cue for other comigrating cells. Such a dual role of CCR7 as a GPCR that both senses and consumes its ligand can thus provide a novel mode of cellular self-organization.},
  author       = {Alanko, Jonna H and Ucar, Mehmet C and Canigova, Nikola and Stopp, Julian A and Schwarz, Jan and Merrin, Jack and Hannezo, Edouard B and Sixt, Michael K},
  issn         = {2470-9468},
  journal      = {Science Immunology},
  keywords     = {General Medicine, Immunology},
  number       = {87},
  publisher    = {American Association for the Advancement of Science},
  title        = {{CCR7 acts as both a sensor and a sink for CCL19 to coordinate collective leukocyte migration}},
  doi          = {10.1126/sciimmunol.adc9584},
  volume       = {8},
  year         = {2023},
}

@article{12259,
  abstract     = {Theoretical foundations of chaos have been predominantly laid out for finite-dimensional dynamical systems, such as the three-body problem in classical mechanics and the Lorenz model in dissipative systems. In contrast, many real-world chaotic phenomena, e.g., weather, arise in systems with many (formally infinite) degrees of freedom, which limits direct quantitative analysis of such systems using chaos theory. In the present work, we demonstrate that the hydrodynamic pilot-wave systems offer a bridge between low- and high-dimensional chaotic phenomena by allowing for a systematic study of how the former connects to the latter. Specifically, we present experimental results, which show the formation of low-dimensional chaotic attractors upon destabilization of regular dynamics and a final transition to high-dimensional chaos via the merging of distinct chaotic regions through a crisis bifurcation. Moreover, we show that the post-crisis dynamics of the system can be rationalized as consecutive scatterings from the nonattracting chaotic sets with lifetimes following exponential distributions. },
  author       = {Choueiri, George H and Suri, Balachandra and Merrin, Jack and Serbyn, Maksym and Hof, Björn and Budanur, Nazmi B},
  issn         = {1089-7682},
  journal      = {Chaos: An Interdisciplinary Journal of Nonlinear Science},
  keywords     = {Applied Mathematics, General Physics and Astronomy, Mathematical Physics, Statistical and Nonlinear Physics},
  number       = {9},
  publisher    = {AIP Publishing},
  title        = {{Crises and chaotic scattering in hydrodynamic pilot-wave experiments}},
  doi          = {10.1063/5.0102904},
  volume       = {32},
  year         = {2022},
}

@article{11182,
  abstract     = {Immune cells are constantly on the move through multicellular organisms to explore and respond to pathogens and other harmful insults. While moving, immune cells efficiently traverse microenvironments composed of tissue cells and extracellular fibers, which together form complex environments of various porosity, stiffness, topography, and chemical composition. In this protocol we describe experimental procedures to investigate immune cell migration through microenvironments of heterogeneous porosity. In particular, we describe micro-channels, micro-pillars, and collagen networks as cell migration paths with alternative pore size choices. Employing micro-channels or micro-pillars that divide at junctions into alternative paths with initially differentially sized pores allows us to precisely (1) measure the cellular translocation time through these porous path junctions, (2) quantify the cellular preference for individual pore sizes, and (3) image cellular components like the nucleus and the cytoskeleton. This reductionistic experimental setup thus can elucidate how immune cells perform decisions in complex microenvironments of various porosity like the interstitium. The setup further allows investigation of the underlying forces of cellular squeezing and the consequences of cellular deformation on the integrity of the cell and its organelles. As a complementary approach that does not require any micro-engineering expertise, we describe the usage of three-dimensional collagen networks with different pore sizes. Whereas we here focus on dendritic cells as a model for motile immune cells, the described protocols are versatile as they are also applicable for other immune cell types like neutrophils and non-immune cell types such as mesenchymal and cancer cells. In summary, we here describe protocols to identify the mechanisms and principles of cellular probing, decision making, and squeezing during cellular movement through microenvironments of heterogeneous porosity.},
  author       = {Kroll, Janina and Ruiz-Fernandez, Mauricio J.A. and Braun, Malte B. and Merrin, Jack and Renkawitz, Jörg},
  issn         = {2691-1299},
  journal      = {Current Protocols},
  number       = {4},
  publisher    = {Wiley},
  title        = {{Quantifying the probing and selection of microenvironmental pores by motile immune cells}},
  doi          = {10.1002/cpz1.407},
  volume       = {2},
  year         = {2022},
}

@article{12109,
  abstract     = {Kelvin probe force microscopy (KPFM) is a powerful tool for studying contact electrification (CE) at the nanoscale, but converting KPFM voltage maps to charge density maps is nontrivial due to long-range forces and complex system geometry. Here we present a strategy using finite-element method (FEM) simulations to determine the Green's function of the KPFM probe/insulator/ground system, which allows us to quantitatively extract surface charge. Testing our approach with synthetic data, we find that accounting for the atomic force microscope (AFM) tip, cone, and cantilever is necessary to recover a known input and that existing methods lead to gross miscalculation or even the incorrect sign of the underlying charge. Applying it to experimental data, we demonstrate its capacity to extract realistic surface charge densities and fine details from contact-charged surfaces. Our method gives a straightforward recipe to convert qualitative KPFM voltage data into quantitative charge data over a range of experimental conditions, enabling quantitative CE at the nanoscale.},
  author       = {Pertl, Felix and Sobarzo Ponce, Juan Carlos A and Shafeek, Lubuna B and Cramer, Tobias and Waitukaitis, Scott R},
  issn         = {2475-9953},
  journal      = {Physical Review Materials},
  number       = {12},
  publisher    = {American Physical Society},
  title        = {{Quantifying nanoscale charge density features of contact-charged surfaces with an FEM/KPFM-hybrid approach}},
  doi          = {10.1103/PhysRevMaterials.6.125605},
  volume       = {6},
  year         = {2022},
}