Biology subjects

Selvaganapathy, P. R.

Publications and source records attributed to Selvaganapathy, P. R..

7 recordsLinked to original sources

bioRxiv2025

Heavy Metal Exposure Disrupts Electrotactic Behavior in Caenorhabditis elegans

Environmental toxicants such as heavy metals can profoundly impact organismal physiology, yet sensitive and rapid behavioral assays to quantify such effects are limited. Here, we employed a microfluidic-based electrotaxis assay to systematically evaluate the impact of chronic exposure to metal salts on the electrotactic swimming behavior of the nematode Caenorhabditis elegans. We report that exposure to Ag, Hg, MeHg, Cu, Mn, and Pb significantly alters electrotaxis speed. Notably, Cu required higher concentrations to induce phenotypes, whereas Ag and Hg disrupted behavior at lower doses. Three other metals (Ni, Fe, and Cd) did not elicit marked electrotaxis defects. Bioaccumulation analysis of Cu, Ag, Hg, and MeHg via ICP-MS revealed that MeHg was present in highest amount in worms. Consistent with this, MeHg showed the highest toxicity. We also found dopaminergic neurodegeneration in most metal-exposed animals, correlating with behavioral impairments. Although heat shock factor-1 (HSF-1) and its downstream target hsp-16.2 were induced by some metals, their expression did not consistently correlate with electrotaxis defects. Moreover, metal-induced impairments persisted even after recovery on toxin-free media, indicating possible irreversible damage. Our findings establish electrotaxis in C. elegans as a robust, non-invasive assay to assess neurobehavioral toxicity and demonstrate its utility for detecting sub-lethal impacts of environmental metals.

animal behavior and cognition↗

bioRxiv2024

Open-source 3D printed manifolds for exposure studies using human airway epithelial cells

RationaleInhalation of airborne stimuli can damage the airway epithelium, increasing the risk of developing respiratory or systemic diseases. In vitro studies using air-liquid interface cell cultures enable controlled investigation of cellular responses to relevant exposures. Commercial in vitro exposure systems provide precise and reproducible dosage but require significant capital investment and are not amenable to customization. Research groups interested in respiratory exposure science may benefit from a more accessible alternative open-source exposure system. We present 3D printed manifolds for applying a range of airborne exposures uniformly across standard, commercially available 6- and 24-well plates with air-liquid interface culture inserts. MethodsA simple chamber-style exposure system and the manifolds were evaluated for exposure uniformity via computational fluid dynamics simulations and deposition of nebulized FITC-labelled dextran. The chamber and manifolds were manufactured using a stereolithography 3D printer. Cannabis concentrate vapor was generated from 3 different vaporizers and applied to well plates using the manifold system. Calu-3 cells were cultured on Transwell inserts and exposed to whole tobacco smoke or room air. ResultsThe manifolds produced less variation in simulated air velocities and physical deposition of FITC-dextran aerosol deposition across well plates compared to those of the chamber-style exposure system. Distinct doses of cannabis concentrate vapour were delivered to well plates with low variation among wells. Whole tobacco smoke exposure using the manifold system induced functional changes in Calu-3 airway epithelial cell barrier function, cytokine production (IL-6 and IL-8), and cell membrane potential. ConclusionsCollectively, our data demonstrate the feasibility and the validity of our open-source 3D printed manifolds for use in studying various respiratory exposures and position our designs as more accessible options in parallel with commercially available systems. All article content is licensed under a Creative Commons Attribution (CC BY-NC 4.0) license (https://creativecommons.org/licenses/by-nc/4.0/).

bioengineering↗

bioRxiv2022

Red blood cell dynamics in extravascular biological tissues modelled as canonical disordered porous media

The dynamics of blood flow in the smallest vessels and passages of the human body, where the cellular character of blood becomes prominent, plays a dominant role in the transport and exchange of solutes. Recent studies have revealed that the micro-haemodynamics of a vascular network is underpinned by its interconnected structure, and certain structural alterations such as capillary dilation and blockage can substantially change blood flow patterns. However, for extravascular media with disordered microstructure (e.g., the porous intervillous space in the placenta), it remains unclear how the mediums structure affects the haemodynamics. Here, we simulate cellular blood flow in simple models of canonical porous media representative of extravascular biological tissue, with corroborative microfluidic experiments performed for validation purposes. For the media considered here, we observe three main effects: first, the relative apparent viscosity of blood increases with the structural disorder of the medium; second, the presence of red blood cells (RBCs) dynamically alters the flow distribution in the medium; third, increased structural disorder of the medium can promote a more homogeneous distribution of RBCs. Our findings contribute to a better understanding of the cellscale haemodynamics that mediates the relationship linking the function of certain biological tissues to their microstructure.

biophysics↗

bioRxiv2020

An Adhesive Based Fabrication Technique for Culture of Lung Airway Epithelial Cells with Applications in Microfluidics and Lung on a Chip

1This work describes a versatile and cost-effective cell culture method for growing adherent cells on a porous membrane using pressure-sensitive double-sided adhesives. This technique allows cell culture using conventional methods and easy transfer to microfluidic chip devices. To support the viability of our system, we evaluate the toxicity effect of four different adhesives on two distinct airway epithelial cell lines and show functional applications for microfluidic cell culture chip fabrication. We showed that cells could be grown and expanded on a "floating" membrane, which can be transferred upon cell confluency to a microfluidic chip for further analysis. The viability of cells and their inflammatory responses to IL-1{beta} stimulation was investigated. Such a technique would be useful to culture cells in a conventional fashion, which is more convenient and faster, and stimulate cells in an advanced model with perfusion when needed.

bioengineering↗

bioRxiv2020

PHAIR, A biosensor for pH measurement in air-liquid interface of human airway epithelial cells

1In many biological systems, pH can be used as a parameter to understand and study cell dynamics. However, measuring pH in live cell culture is limited by the sensor ion specificity, proximity to the cell surface, and scalability. Commercially available pH sensors are difficult to integrate into a small-scale cell culture system due to their size and are not cost-effective for disposable use. We made PHAIR - a new pH sensor that uses a micro-wire format to measure pH in vitro human airway cell culture. Tungsten micro-wires were used as the working electrodes, and silver micro-wires with a silver/silver chloride coating were used as a pseudo reference electrode. pH sensitivity, in a wide and narrow range, and stability of these sensors were tested in common standard buffer solutions as well as in culture media of human airway epithelial cells grown at the air-liquid interface in a 24 well cell culture plate. When measuring the pH of cells grown under basal and challenging conditions using PHAIR, cell viability and cytokine responses were not affected. Our results confirm that micro-wires-based sensors have the capacity for miniaturization, and detection of diverse ions while maintaining sensitivity. This suggests the broad application of PHAIR in various biological experimental settings.

bioengineering↗

bioRxiv2020

Surface modification of PDMS-based microfluidic devices with collagen using polydopamine as a spacer to enhance primary human bronchial epithelial cell adhesion

Polydimethylsiloxane (PDMS) is a silicone-based synthetic material that is used in various biomedical applications due to its properties, including transparency, flexibility, permeability to gases, and ease of use. Though PDMS facilitates and realizes the fabrication of complicated geometries at the micro and nano scales, it does not optimally interact with cells for adherence and proliferation. Different strategies have been proposed to render PDMS to enhance cell attachment. The majority of these surface modification techniques have been offered for a static cell culture system. However, dynamic cell culture systems such as organ-on-a-chip devices are demanding platforms that recapitulate the complexity of a living tissue microenvironment. For organ-on-a-chip platforms, PDMS surfaces are usually coated by ECM proteins, which occur as a result of physical, weak bonding between PDMS and ECM proteins, and this binding can be degraded when it is exposed to shear stresses. This work reports static and dynamic coating methods to covalently bind collagen within a PDMS-based microfluidic device using polydopamine (PDA). These coating methods were evaluated using water contact angle measurement and atomic force microscopy (AFM) to find the optimum coating conditions. The biocompatibility of collagen-coated PDMS devices was assessed by culturing primary human bronchial epithelial cells (HBECs) in microfluidic devices. It was shown that both PDA coating methods could be used to bind collagen, thereby improving cell adhesion (around three times higher) without showing any discernible difference. These results suggested that such a surface modification can be used to coat an extracellular matrix protein onto PDMS-based microfluidic devices.

bioengineering↗

bioRxiv2020

A Pumpless Microfluidic Neonatal Lung Assist Device for Support of Preterm Neonates in Respiratory Distress

Premature neonates suffer from respiratory morbidity as their lungs are immature and current supportive treatment such as mechanical ventilation or extracorporeal membrane oxygenation (ECMO) cause iatrogenic injuries. A non-invasive and biomimetic concept known as the "artificial placenta" would be beneficial to overcome complications associated with the current respiratory support of preterm infants. Here, a pumpless oxygenator connected to the systemic circulation supports the lung function to relieve respiratory distress. In this paper, we demonstrate the first successful operation of a microfluidic, artificial placenta type neonatal lung assist device (LAD) on a newborn piglet model which is the closest representation of preterm human infants. This LAD has high oxygenation capability in both pure oxygen and room air as the sweep gas. It was able to relieve the respiratory distress that the newborn piglet was put under during experimentation, repeatedly and over significant duration of time. These findings indicate that this LAD has potential application as a biomimetic artificial placenta to support respiratory needs of preterm neonates.

bioengineering↗