A Novel Cryogenic Approach to 3D Printing Cytocompatible, Conductive, Hydrogel-Based Inks.

In the field of tissue engineering and regenerative medicine, developing cytocompatible 3D conductive scaffolds that mimic the native extracellular matrix is crucial for the engineering of excitable cells and tissues. In this study, a custom cryogenic extrusion 3D printer was developed, which afforded control over both the ink and printing surface temperatures. Using this approach, aqueous inks were printed into well-defined layers with high precision.

Green IoT Event Detection for Carbon-Emission Monitoring in Sensor Networks.

This research addresses the intersection of low-power microcontroller technology and binary classification of events in the context of carbon-emission reduction. The study introduces an innovative approach leveraging microcontrollers for real-time event detection in a homogeneous hardware/firmware manner and faced with limited resources. This showcases their efficiency in processing sensor data and reducing power consumption without the need for extensive training sets.

Advanced IoT Pressure Monitoring System for Real-Time Landfill Gas Management.

This research presents a novel stand-alone device for the autonomous measurement of gas pressure levels on an active landfill site, which enables the real-time monitoring of gas dynamics and supports the early detection of critical events. The developed device employs advanced sensing technologies and wireless communication capabilities, enabling remote data transmission and access via the Internet. Through extensive field experiments, we demonstrate the high sampling rate of the device and its ability to detect significant events related to gas generation dynamics in landfills, such as flare shutdowns or blockages that could lead to hazardous conditions.

Critical importance of RGB color space specificity for colorimetric bio/chemical sensing: A comprehensive study.

The use of the RGB color model in colorimetric chemical sensing via imaging techniques is widely prevalent in the literature. However, the lack of specificity in the selection of RGB color space during capture and analysis presents a significant challenge in creating standardised methods for this field and possible discrepancies. In this study, we conducted a comprehensive comparison and contrast of a total of 68 RGB color spaces to evaluate their respective impacts on colorimetric bio/chemical sensing.

LED PEDD Discharge Photometry: Effects of Software Driven Measurements for Sensing Applications.

This work explores the effects of embedded software-driven measurements on a sensory target when using a LED as a photodetector. Water turbidity is used as the sensory target in this study to explore these effects using a practical and important water quality parameter. Impacts on turbidity measurements are examined by adopting the Paired Emitter Detector Diode (PEDD) capacitive discharge technique and comparing common embedded software/firmware implementations.

Advances in Optical Based Turbidity Sensing Using LED Photometry (PEDD).

Turbidity is one of the primary metrics to determine water quality in terms of health and environmental concerns, however analysis typically takes place in centralized facilities, with samples periodically collected and transported there. Large scale autonomous deployments (WSNs) are impeded by both initial and per measurement costs. In this study we employ a Paired Emitter-Detector Diode (PEDD) technique to quantitatively measure turbidity using analytical grade calibration standards.

Fabrication of Aligned Biomimetic Gellan Gum-Chitosan Microstructures through 3D Printed Microfluidic Channels and Multiple In Situ Cross-Linking Mechanisms.

In this study we use a combination of ionic- and photo-cross-linking to develop a fabrication method for producing biocompatible microstructures using a methacrylated gellan gum (a polyanion) and chitosan (a polycation) in addition to lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as the photoinitiator. This work involves the development of a low-cost, portable 3D bioprinter and a customized extrusion mechanism for controlled introduction of the materials through a 3D printed microfluidic nozzle, before being cross-linked in situ to form robust microstructure bundles. The formed microstructures yielded a diameter of less than 1 μm and a tensile strength range of ∼1 MPa.

Computer-Aided Design and Manufacturing (CAD/CAM) for Bioprinting.

Three-dimensional (3D) printing of human tissues and organs has been an exciting area of research for almost three decades [Bonassar and Vacanti. J Cell Biochem. 72(Suppl 30-31):297-303 (1998)].

Patterning and process parameter effects in 3D suspension near-field electrospinning of nanoarrays.

The extracellular matrix (ECM) contains nanofibrous proteins and proteoglycans. Nanofabrication methods have received growing interest in recent years as a means of recapitulating these elements within the ECM. Near-field electrospinning (NFES) is a versatile fibre deposition method, capable of layer-by-layer nano-fabrication.

Understanding the loss mechanisms in high-performance solution-processed small molecule bulk heterojunction solar cells doped with a PFN impurity.

Contamination of the active layer with an impurity could result in significant degradation in the performance of bulk heterojunction (BHJ) solar cells as a result of enhancing the loss of the charge carriers via a trap-assisted recombination. In this study, PFN as an impurity was intentionally introduced to a BHJ solar cell composed of a high-performance solution-processed small molecule (p-DTS(FBTTh) as a donor and PCBM as an acceptor. The power conversion efficiency (PCE) of PFN doped devices degrades owing to the reduction of short-circuit current (J) and fill factor (FF).

Quantitative ultrasound imaging of cell-laden hydrogels and printed constructs.

In the present work we have revisited the application of quantitative ultrasound imaging (QUI) to cellular hydrogels, by using the reference phantom method (RPM) in combination with a local attenuation compensation algorithm. The investigated biological samples consisted of cell-laden collagen hydrogels with PC12 neural cells. These cell-laden hydrogels were used to calibrate the integrated backscattering coefficient (IBC) as a function of cell density, which was then used to generate parametric images of local cell density.

A direct 3D suspension near-field electrospinning technique for the fabrication of polymer nanoarrays.

Near-field electrospinning (NFES) is widely recognized as a versatile nanofabrication method, one suitable for applications in tissue engineering. Rapid developments in this field have given rise to layered nanofibrous scaffolds. However, this electrostatic fabrication process is limited by the electric field inhibitory effects of polymer deposition.

A contactless approach for monitoring the mechanical properties of swollen hydrogels.

Using a customized ultrasound setup we investigate the feasibility of using a contactless approach to study the bulk mechanical properties of swollen hydrogels. The study involved two different hydrogels, gelatin methacrylate (GelMa) and green algae extract methacrylate (GAEM), which were prepared to provide materials with varying modulus and different swelling properties. Two approaches have been developed.

A Wearable Device for Monitoring Sweat Rates via Image Analysis.

A feasibility study on a new technique capable of monitoring localized sweat rate is explored in this paper. Wearable devices commonly used in clinical practice for sweat sampling (i.e.

Enhanced Antifouling Properties of Carbohydrate Coated Poly(ether sulfone) Membranes.

Poly(ether sulfone) membranes (PES) were modified with biologically active monosaccharides and disaccharides using aryldiazonium chemistry as a mild, one-step, surface-modification strategy. We previously proposed the modification of carbon, metals, and alloys with monosaccharides using the same method; herein, we demonstrate modification of PES membranes and the effect of chemisorbed carbohydrate layers on their resistance to biofouling. Glycosylated PES surfaces were characterized using spectroscopic methods and tested against their ability to interact with specific carbohydrate-binding proteins.

Self-propelled chemotactic ionic liquid droplets.

Herein we report the chemotactic behaviour of self-propelled droplets composed solely of the ionic liquid trihexyl(tetradecyl)phosphonium chloride ([P(6,6,6,14)][Cl]). These droplets spontaneously move along an aqueous-air boundary in the direction of chloride gradients to specific destinations due to asymmetric release of [P(6,6,6,14)](+) cationic surfactant from the droplet into the aqueous phase.

Portable integrated microfluidic analytical platform for the monitoring and detection of nitrite.

A wireless, portable, fully-integrated microfluidic analytical platform has been developed and applied to the monitoring and determination of nitrite anions in water, using the Griess method. The colour intensity of the Griess reagent nitrite complex is detected using a low cost Paired Emitter Detector Diode, while on-chip fluid manipulation is performed using a biomimetic photoresponsive ionogel microvalve, controlled by a white light LED. The microfluidic analytical platform exhibited very low limits of detection (34.

Dynamic pH mapping in microfluidic devices by integrating adaptive coatings based on polyaniline with colorimetric imaging techniques.

In this paper we present a microfluidic device that has integrated pH optical sensing capabilities based on polyaniline. The optical properties of polyaniline coatings change in response to the pH of the solution that is flushed inside the microchannel offering the possibility of monitoring pH in continuous flow over a wide pH range throughout the entire channel length. This work also features an innovative detection system for spatial localisation of chemical pH gradients along microfluidic channels through the use of a low cost optical device.

Remote real-time monitoring of subsurface landfill gas migration.

The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels.

Wearable technology for bio-chemical analysis of body fluids during exercise.

This paper details the development of a textile based fluid handling system with integrated wireless biochemical sensors. Such research represents a new advancement in the area of wearable technologies. The system contains pH, sodium and conductivity sensors.