The understanding of force interplays between an organism and its environment is imperative in biological processes. Noticeably scarce from the study of C. elegans locomotion is the measurement of the nematode locomotion forces together with other important locomotive metrics. To bridge the current gap, we present the investigation of C. elegans muscular forces and locomotion metrics (speed, amplitude and wavelength) in one single assay. This assay uses polydimethylsiloxane (PDMS) micropillars as force sensing elements and, by variation of the pillar arrangement, introduces microstructure. To show the usefulness of the assay, twelve wild-type C. elegans sample worms were tested to obtain a total of 4665 data points. The experimental results lead to several key findings. These include: (1) maximum force is exerted when the pillar is in contact with the middle part of the worm body, (2) C. elegans locomotion forces are highly dependent on the structure of the surrounding environment, (3) the worms' undulation frequency and locomotion speed increases steadily from the narrow spacing of ‘honeycomb’ design to the wider spacing of ‘lattice’ pillar arrangement, and (4) C. elegans maintained their natural sinusoidal movement in the microstructured device, despite the existence of PDMS micropillars. The assay presented here focuses on wild type C. elegans, but the method can be easily applied to its mutants and other organisms. In addition, we also show that, by inverting the measurement device, worm locomotion behaviour can be studied in various substrate environments normally unconducive to flexible pillar fabrication. The quantitative measurements demonstrated in this work further improve the understanding of C. elegans mechanosensation and locomotion.

This paper describes a process for the layer-by-layer fabrication and integration of luminescent dye-based optical oxygen sensors into microfluidic devices. Application of oxygen-sensitive platinum(II) octaethylporphyrin ketone fluorescent dye dissolved in polystyrene onto glass substrates by spin-coating was studied. Soft lithography with polydimethylsiloxane (PDMS) stamps and reactive ion etching in oxygen plasma were used to produce sensor patterns with a minimum feature size of 25 μm. Sensors patterns were integrated into a PDMS microfluidic device by plasma bonding. No degradation of the sensor response as a result of the lithography and pattern-transfer processes was detected. Gaseous and dissolved oxygen (DO) detection was characterised using fluorescence microscopy. The intensity signal ratio of the sensor films was found to increase almost two-fold from 3.6 to 6.8 by reducing film thickness from 1.3 μm to 0.6 μm. Calibration of DO measurement showed linear Stern–Volmer behaviour that was constant for flow rates from 0.5 to 2 mL min⁻¹. The calibrated sensors were subsequently used to demonstrate laterally resolved detection of oxygen inside a microfluidic channel. The fabrication process provides a novel, easy to use method for the repeatable integration of optical oxygen sensors into cell-culture and lab-on-a-chip devices.

Rust fungi (Pucciniales) are a diverse group of plant pathogens in natural and agricultural systems. They pose ongoing threats to the diversity of native flora and cause annual crop yield losses. Agricultural rusts are predominantly managed with fungicides and breeding for resistance, but new control strategies are needed on non‐agricultural plants and in fragile ecosystems. RNA interference (RNAi) induced by exogenous double‐stranded RNA (dsRNA) has promise as a sustainable approach for managing plant‐pathogenic fungi, including rust fungi. We investigated the mechanisms and impact of exogenous dsRNA on rust fungi through in vitro and whole‐plant assays using two species as models, Austropuccinia psidii (the cause of myrtle rust) and Coleosporium plumeriae (the cause of frangipani rust) . In vitro, dsRNA either associates externally or is internalized by urediniospores during the early stages of germination. The impact of dsRNA on rust infection architecture was examined on artificial leaf surfaces. dsRNA targeting predicted essential genes significantly reduced germination and inhibited development of infection structures, namely appressoria and penetration pegs. Exogenous dsRNA sprayed onto 1‐year‐old trees significantly reduced myrtle rust symptoms . Furthermore, we used comparative genomics to assess the wide‐scale amenability of dsRNA to control rust fungi. We sequenced genomes of six species of rust fungi, including three new families (Araucariomyceaceae, Phragmidiaceae, and Skierkaceae) and identified key genes of the RNAi pathway across 15 species in eight families of Pucciniales. Together, these findings indicate that dsRNA targeting essential genes has potential for broad‐use management of rust fungi across natural and agricultural systems.

Through-mask electrochemical micromachining (TMEMM) is a versatile microfabrication technique, which combines anodic metal-shaping and -finishing steps in a single operation for the purpose of microstructuring a wide range of electrically conductive materials. It has been extensively utilized for the manufacture of precision-engineered components in microsystems, such as microlenses, microprobes, microactuators, microchannels and microvalves. This is because TMEMM is able to mass-produce parts; it is applicable to difficult-to-etch materials and operable under polishing conditions. This review provides an in-depth summary of the current state of TMEMM and presents key concepts relevant to its application. To this end, the interplay between the current distribution, mass-transfer effects and surface-film formation is discussed, and its effect on the machining rate, shape profile and surface finish is highlighted. Also, past incarnations of TMEMM are reviewed in terms of their masking method, substrate material, electrolyte composition and technical application. Techno-economic aspects of TMEMM are debated in relation to potential rival techniques, taking microreactor fabrication as an example for a novel area of application. This is followed by an overview of process variations and recent developments.