Socially interactive robots are steadily entering the realm of human experience. Social robots are being deployed for applications in entertainment and companionship, health and well-being. We argue that the design of social robots is not neutral as they are exemplars of persuasive technologies. By virtue of its physical embodiment and its anthropomorphic design which take into account an intimate understanding of human and social psychology, communication and behavior, they persuade human beings into the illusion of a mutually empathic and socially reciprocative interaction. In recent years, a design trend has emerged in digital media and web technologies: Dark Patterns. They use deceptive techniques to persuade people to commit actions that are not in their best interest and undermine their autonomy to further the interest of designers, companies or their shareholders. We highlight that social robots may harbor these dark patterns and they can be potent social actors that can push our darwinian buttons to undermine our time, monetary situation and privacy, effectively harming our health and well-being.

Quantitative micromechanical characterization of single cells and multicellular tissues or organisms is of fundamental importance to the study of cellular growth, morphogenesis, and cell-cell interactions. However, due to limited manipulation capabilities at the microscale, systems used for mechanical characterizations struggle to provide complete three-dimensional coverage of individual specimens. Here, we combine an acoustically driven manipulation device with a micro-force sensor to freely rotate biological samples and quantify mechanical properties at multiple regions of interest within a specimen. The versatility of this tool is demonstrated through the analysis of single Lilium longiflorum pollen grains, in combination with numerical simulations, and individual Caenorhabditis elegans nematodes. It reveals local variations in apparent stiffness for single specimens, providing previously inaccessible information and datasets on mechanical properties that serve as the basis for biophysical modelling and allow deeper insights into the biomechanics of these living systems. It is currently challenging to mechanically assess 3D specimens without manual handling. Here the authors combine a micro-force sensor and an acoustically controlled manipulation device to enable rotation of samples while assessing mechanical properties at the chosen region.

Acoustically excited microstructures have demonstrated significant potential for small scale biomedical applications by overcoming major microfluidic limitations. Recently, the application of oscillating microbubbles has demonstrated their superiority over acoustically excited solid structures due to their enhanced acoustic streaming at low input power. However, their limited temporal stability hinders their direct applicability for industrial or clinical purposes. Here, we introduce the embedded microbubble, a novel acoustofluidic design based on the combination of solid structures (polydimethylsiloxane) and microbubbles (air-filled cavity) to combine benefits of both approaches while minimizing their drawbacks. We investigate the influence of various design parameters and geometrical features through numerical simulations and experimentally evaluate their manipulation capabilities. Finally, we demonstrate the capabilities of our design for microfluidic applications by investigating its mixing performance as well as through the controlled rotational manipulation of individual HeLa cells.

The world was unprepared for the COVID-19 pandemic, and recovery is likely to be a long process. Robots have long been heralded to take on dangerous, dull, and dirty jobs, often in environments that are unsuitable for humans. Could robots be used to fight future pandemics? We review the fundamental requirements for robotics for infectious disease management and outline how robotic technologies can be used in different scenarios, including disease prevention and monitoring, clinical care, laboratory automation, logistics, and maintenance of socioeconomic activities. We also address some of the open challenges for developing advanced robots that are application oriented, reliable, safe, and rapidly deployable when needed. Last, we look at the ethical use of robots and call for globally sustained efforts in order for robots to be ready for future outbreaks.

The precise manipulation of single cells and organisms opens exciting new possibilities for biological research. In this work, an acoustic rotational manipulation method for imaging single cells of different plant species (pollen grains of !ilium longiflorum and Arabidopsis thafiana) is demonstrated. Acoustically activated microbubbles generate radiation forces as well as microvortices in the aqueous medium, which allow various specimens to be trapped and precisely rotated. The rotational behavior of individual plant cells is studied and their motion to facilitate 3D fluorescent microscopy is controlled. The use of this manipulation technique for high-resolution 3D optical reconstructions of nontransparent samples is demonstrated. The applicability of this method for open-microchannel arrangement, which may enable multiplexed 3D access to samples for microsurgery and injection, is further demonstrated.

Advancing plant biological research has an important function in the food chain and economic systems. In article number 1800527, Daniel Ahmed and co-workers present a rotational manipulation method using acoustically activated microbubbles to investigate opaque and non-spherical plant cells. The rotational behavior of the plant cells is characterized in open and closed microchannels for 3D visualization and interaction.

[This corrects the article DOI: 10.1371/journal.pone.0168138.].

Particle tracking has emerged as a powerful tool for investigating the swarm control of microrobots and the dynamic biological processes in the life sciences. In seed plants, pollen tubes, a part of the male gametophyte, are excellent models for understanding plant growth and cellular behavior, because vesicle motion within pollen tubes reveals important information about vesicle function and interactions. Conventional vesicle tracking is based on spatiotemporal image analysis, which requires high-quality images and vesicles with constant velocity. For in vivo tracking, vesicles may disappear in some frames, and image sequences may have spatial and temporal distortions, which hamper vesicle tracking for broader applications. In this paper, we studied intracellular motion during pollen tube growth with an optical flow method. Streaming images from confocal and optical microscopes were recorded to study the intracellular motion of vesicles of different size. Local motion for each vesicle was detected using a local displacement vector field. The displacement from two adjacent frames was then calculated. The flow field shows information such as the dynamics of vesicle secretion, endocytosis, exocytosis, and cytoskeletal stability. Vesicles from different regions inside the tube were tracked simultaneously with a Kanade-Lucas-Tomasi (KLT) feature matching algorithm. The spatial and temporal characteristics of intracellular vesicles were evaluated. The proposed methods can be of great use for studying the dynamics of fluorescently tagged particles in biological systems.

Pollen tubes are tip-growing plant cells that deliver the sperm cells to the ovules for double fertilization of the egg cell and the endosperm. Various directional cues can trigger the reorientation of pollen tube growth direction on their passage through the female tissues. Among the external stimuli, protons serve an important, regulatory role in the control of pollen tube growth. The generation of local guidance cues has been challenging when investigating the mechanisms of perception and processing of such directional triggers in pollen tubes. Here, we developed and characterized a microelectrode device to generate a local proton gradient and proton flux through water electrolysis. We confirmed that the cytoplasmic pH of pollen tubes varied with environmental pH change. Depending on the position of the pollen tube tip relative to the proton gradient, we observed alterations in the growth behavior, such as bursting at the tip, change in growth direction, or complete growth arrest. Bursting and growth arrest support the hypothesis that changes in the extracellular H+ concentration may interfere with cell wall integrity and actin polymerization at the growing tip. A change in growth direction for some pollen tubes implies that they can perceive the local proton gradient and respond to it. We also showed that the growth rate is directly correlated with the extracellular pH in the tip region. Our microelectrode approach provides a simple method to generate protons and investigate their effect on plant cell growth.

Fibroblast growth factor 2 (FGF-2), an important paracrine growth factor, binds electrostatically with low micromolar affinity to heparan sulfates present on extracellular matrix proteins. A single molecular analysis served as a basis to decipher the nanomechanical mechanism of the interaction between FGF-2 and the heparan sulfate surrogate, heparin, with a modular atomic force microscope (AFM) design combining magnetic actuators with force measurements at the low force regime (1 × 101 to 1 × 104 pN/s). Unbinding events between FGF-2-heparin complexes were specific and short-lived. Binding between FGF-2 and heparin had strong slip bond characteristics as demonstrated by a decrease of lifetime with tensile force on the complex. Unbinding forces between FGF-2 and heparin were further detailed at different pH as relevant for (patho-) physiological conditions. An acidic pH environment (5.5) modulated FGF-2-heparin binding as demonstrated by enhanced rupture forces needed to release FGF-2 from the heparin-FGF-2 complex as compared to physiological conditions. This study provides a mechanistic and hypothesis driven model on how molecular forces may impact FGF-2 release and storage during tissue remodeling and repair.

The phenomenon of magnetostriction can wirelessly couple external magnetic fields to generate structural motion. This is an attractive solution for remote delivery of power to microactuators in constrained environments. This study discusses the magnetostriction of electrosynthesized CoFe thin film microactuators. Electrodeposition is commonly employed for the fabrication of metallic thin films, however the magnetostriction of such films has been rarely investigated. In particular, the magnetostrictive behavior of electroplated CoFe films is poorly understood, despite the high magnetostriction capabilities of CoFe alloys. In this work, uniformly thick and smooth Co0.65Fe0.35 thin films were electrochemically grown on commercially available micron-scale cantilevers. The CoFe thin films were characterized for their morphology, composition, crystal structure, and magnetic properties. The AC magnetostrictive response of the cantilevers was measured interferometrically and the actuator exhibited a maximum expected displacement of 86nm.

Wireless capsule endoscopy (WCE) is a powerful tool for medical screening and diagnosis, where a small capsule is swallowed and moved by means of natural peristalsis and gravity through the human gastrointestinal (GI) tract. The camera‐integrated capsule allows for visualization of the small intestine, a region which was previously inaccessible to classical flexible endoscopy. As a diagnostic tool, it allows to localize the sources of bleedings in the middle part of the gastrointestinal tract and to identify diseases, such as inflammatory bowel disease (Crohn's disease), polyposis syndrome, and tumors. The screening and diagnostic efficacy of the WCE, especially in the stomach region, is hampered by a variety of technical challenges like the lack of active capsular position and orientation control. Therapeutic functionality is absent in most commercial capsules, due to constraints in capsular volume and energy storage. The possibility of using body‐exogenous magnetic fields to guide, orient, power, and operate the capsule and its mechanisms has led to increasing research in Magnetically Guided Capsule Endoscopy (MGCE). This work shortly reviews the history and state‐of‐art in WCE technology. It highlights the magnetic technologies for advancing diagnostic and therapeutic functionalities of WCE. Not restricting itself to the GI tract, the review further investigates the technological developments in magnetically guided microrobots that can navigate through the various air‐ and fluid‐filled lumina and cavities in the body for minimally invasive medicine.

Correction for 'High precision, localized proton gradients and fluxes generated by a microelectrode device induce differential growth behaviors of pollen tubes' by Chengzhi Hu et al., Lab Chip, 2017, 17, 671-680.

Quantification of mechanical properties of tissues, living cells, and cellular components is crucial for the modeling of plant developmental processes such as mechanotransduction. Pollen tubes are tip-growing cells that provide an ideal system to study the mechanical properties at the single cell level. In this article, a lab-on-a-chip (LOC) device is developed to quantitatively measure the biomechanical properties of lily (Lilium longiflorum) pollen tubes. A single pollen tube is fixed inside the microfluidic chip at a specific orientation and subjected to compression by a soft membrane. By comparing the deformation of the pollen tube at a given external load (compressibility) and the effect of turgor pressure on the tube diameter (stretch ratio) with finite element modeling, its mechanical properties are determined. The turgor pressure and wall stiffness of the pollen tubes are found to decrease considerably with increasing initial diameter of the pollen tubes. This observation supports the hypothesis that tip-growth is regulated by a delicate balance between turgor pressure and wall stiffness. The LOC device is modular and adaptable to a variety of cells that exhibit tip-growth, allowing for the straightforward measurement of mechanical properties.

The ability to precisely control the three-dimensional orientation of micrometer-sized biological samples is critical for its phenotypic investigation. We develop an acoustic wave-based microfluidic device that can be used for the trapping and rotational manipulation of single plant cells. Resonant acoustic excitation of air-filled microbubbles generates localized vortices that can be used for the controlled three-dimensional rotation of single cells. We compare the rotational capabilities of microbubble-generated vortices with that of vortices generated by vibration of solid microstructures. We demonstrate the rotational capabilities of the device using single plant cells, the pollen grain.

Wireless capsule endoscopy (WCE) is a powerful tool for medical screening and diagnosis, where a small capsule is swallowed and moved by means of natural peristalsis and gravity through the human gastrointestinal (GI) tract. The camera-integrated capsule allows for visualization of the small intestine, a region which was previously inaccessible to classical flexible endoscopy. As a diagnostic tool, it allows to localize the sources of bleedings in the middle part of the gastrointestinal tract and to identify diseases, such as inflammatory bowel disease (Crohn's disease), polyposis syndrome, and tumors. The screening and diagnostic efficacy of the WCE, especially in the stomach region, is hampered by a variety of technical challenges like the lack of active capsular position and orientation control. Therapeutic functionality is absent in most commercial capsules, due to constraints in capsular volume and energy storage. The possibility of using body-exogenous magnetic fields to guide, orient, power, and operate the capsule and its mechanisms has led to increasing research in Magnetically Guided Capsule Endoscopy (MGCE). This work shortly reviews the history and state-of-art in WCE technology. It highlights the magnetic technologies for advancing diagnostic and therapeutic functionalities of WCE. Not restricting itself to the GI tract, the review further investigates the technological developments in magnetically guided microrobots that can navigate through the various air-and fluid-filled lumina and cavities in the body for minimally invasive medicine. (C) 2017 American Association of Physicists in Medicine [https://doi. org/10.1002/mp. 12299]