Real-Time Micromotor Probe for Immune Neutrophil Activation State.

Neutrophil activation is a hallmark of the immune response. Approaches to identify neutrophil activation in real time are necessary but are still lacking. In this study, magnetic Spirulina micromotors are used as label-free probes that exhibit differences in motility under different neutrophil activation states. This is correlated with different secretions into the extracellular environment by activated/non-activated cells and local environmental viscoelasticity. The micromotor platform can bypass non-activated immune cells while being stopped by activated cells. Thus, the micromotors can serve as label-free biomechanical probes of the immune cell state. They can detect the activation state of target immune cells in real time and with single-cell precision, which provides new ideas for the diagnosis and treatment of diseases while deepening understanding of the biomechanics of activated immune cells.

Adaptive particle patterning in the presence of active synthetic nanomotors.

For the maintenance of a biological system, spatial organization of material condensates within the cell through the dissipation of energy is crucial. Besides directed transport via microtubules, material arrangement can be achieved via motor protein facilitated adaptive active diffusiophoresis. For example, the distribution of membrane proteins during the cell division of Escherichia coli is affected by the MinD system. Synthetic active motors exhibit the ability to simulate natural motors. Here we propose an active Au-Zn nanomotor driven by water and discovered an interesting adaptive interaction mode of the diffusiophoretic Au-Zn nanomotors with passive condensate particles in different environments. It is found that the attraction/repulsion between the nanomotor and passive particles is adaptive, while an interesting hollow pattern is formed with a negatively charged substrate and a cluster pattern is favored with a positively charged substrate.

Mechanical Activation of Immune T Cells via a Water Driven Nanomotor.

As a key step during immune response, antigen recognition requires direct mechanical interaction between T cells and antigen presenting cells. Upon subjection to mechanical forces, mechanotransduction is triggered. In this study, the mechanical forces generated by water driven synthetic Au-Zn nanomotors are used to activate mechanosensitive Jurkat T cells. The triggering and activation of the cellular Ca2+ channel is observed. It is revealed that the mechanosensitive cells experience different degrees of activation upon receiving different mechanical input signals and demonstrate that external mechanical forces can optimize T cell activation. Compared with T cell activation with cytokines which can lead to the risky widespread activation of T cells and systemic immune storm, nanomotors can present mechanical force and achieve localized immune cell stimulation. It is expected that mechano nanomotors will contribute to the emerging T cell immunology field and facilitate more comprehensive understanding of the T cell mechanical response and function.