Microfluidic platform integrated with worm-counting setup for assessing manganese toxicity

Abstract

We reported a new microfluidic system integrated with worm responders for evaluating the environmental manganese toxicity. The micro device consists of worm loading units, worm observing chambers, and a radial concentration gradient generator (CGG). Eight T-shape worm loading units of the micro device were used to load the exact number of worms into the corresponding eight chambers with the assistance of worm responders and doorsills. The worm responder, as a key component, was employed for performing automated worm-counting assay through electric impedance sensing. This label-free and non-invasive worm-counting technique was applied to the microsystem for the first time. In addition, the disk-shaped CGG can generate a range of stepwise concentrations of the appointed chemical automatically and simultaneously. Due to the scalable architecture of radial CGG, it has the potential to increase the throughput of the assay. Dopaminergic (DAergic) neurotoxicity of manganese on C. elegans was quantitatively assessed via the observation of green fluorescence protein-tagged DAergic neurons of the strain BZ555 on-chip. In addition, oxidative stress triggered by manganese was evaluated by the quantitative fluorescence intensity of the strain CL2166. By scoring the survival ratio and stroke frequency of worms, we characterized the dose- and time-dependent mobility defects of the manganese-exposed worms. Furthermore, we applied the microsystem to investigate the effect of natural antioxidants to protect manganese-induced toxicity.

Comparative toxicity of lead (Pb2+), copper (Cu2+), and mixtures of lead and copper to zebrafish embryos on a microfluidic chip

“…Two quarters of the solution flowed into the two adjacent branches, where they met and mixed with one quarter stream of two adjacent source solutions respectively. Wang 12 and Zhang 13 described the solution flowing and the concentration gradient generating in considerable detail in such type of chip. The two dye solutions and the ethanol were disturbed three times and collected through the liquid outlets.…”

“…Meanwhile, it is very meaningful work that our laboratory reported a new microfluidic system integrated with worm responders for evaluating the environmental manganese toxicity. 13 …”

Advanced Microfluidic Assays for Caenorhabditis elegans

“…Micropatterned electrodes on the sidewalls of microfluidic channels (i.e., without blocking optical visibility) provides a simple means of creating electrofluidic glass chips to flexibly control the movement of C. elegans in a sensitive and reproducible manner [101]. Placing the microelectrodes inside the microfluidic environment as close to the animal as possible allows one to create transient pores in the cell membrane, which permits the diffusion of extracellular compounds that are present in the vicinity of the pore into the interior of the cell [102]. All of these results demonstrate the potential of using active microfluidic devices as an alternative to Petri dishes for C. elegans assays.…”

“…One application where microfluidics and fluorescent-based imaging open up aspects that would remain hidden from traditional laboratory techniques is drug screening. C. elegans can be an effective test-bed for a wide range of water-soluble chemical compounds (e.g., glycerol [30,66,74,75], anticancer drugs [48], heavy metals [54], sodium chloride NaCl [58,65,71,83,111,112], copper(II) chloride CuCl 2 [66,74], levamisole [70], manganese [102], antibiotics [104], isoamyl alcohol [113], cyanide [114], etc.). Microfluidic network manipulation allows the automation in a high-throughput manner and under reproducible experimental conditions while analysis of the nematode's chemosensitivity provides a detailed model of how neurons function together to generate behavioral response.…”

Continuous-flow C. elegans fluorescence expression analysis with real-time image processing through microfluidics

“…The microenvironment fabricated by PDMS is a perfect match for the sizes of C. elegans throughout its various growth stages (Qin and Wheeler 2007;Solvas et al 2011). Thus, a series of worm studies have applied microfluidics in imaging analysis (Allen et al 2008;Hulme et al 2007;Zeng et al 2008;Zhao et al 2013), lifespan studies (Ai et al 2014;Clausell-Tormos et al 2008;Hulme et al 2010;Krajniak and Lu 2010;Xian et al 2013), screening (Chung et al 2011;Chung et al 2008;Ghorashian et al 2013;Han et al 2012;Rezai et al 2012;Rohde et al 2007;Solvas et al 2011;Yuan et al 2015), behavioral (Wang et al 2013b), sensing Yang et al 2013;Zhang et al 2014) and neurobiological applications (Chronis et al 2007;Crane et al 2012;Wang et al 2011a;Wang et al 2013a;Wang et al 2011b;Zimmer et al 2009). When integrated with computer software for automatic control, the use of microfluidics can avoid intrinsic issues associated with manual operations, such as variability, bias and errors (Chung et al 2008).…”