Antifouling Copper Surfaces Interfere with Wet Chemical Nitrate Sensors: Characterization and Mechanistic Investigation.

Wet chemical sensors autonomously sample and analyze water using chemical assays. Their internal fluidics are not susceptible to biofouling (the undesirable accumulation of microorganisms, algae, and animals in natural waters) due to the harsh chemical environment and dark conditions; however, the sample intake and filter are potentially susceptible. This paper describes the use of copper intake filters, incorporated to prevent fouling, on two different wet chemical nitrate sensors that each use different variants of the Griess assay (in particular, different nitrate reduction steps) to quantify nitrate concentrations.

Thermo-responsive aqueous two-phase system for two-level compartmentalization.

Hierarchical compartmentalization responding to changes in intracellular and extracellular environments is ubiquitous in living eukaryotic cells but remains a formidable task in synthetic systems. Here we report a two-level compartmentalization approach based on a thermo-responsive aqueous two-phase system (TR-ATPS) comprising poly(N-isopropylacrylamide) (PNIPAM) and dextran (DEX). Liquid membraneless compartments enriched in PNIPAM are phase-separated from the continuous DEX solution via liquid-liquid phase separation at 25 °C and shrink dramatically with small second-level compartments generated at the interface, resembling the structure of colloidosome, by increasing the temperature to 35 °C.

Multifunctional nanocoating for enhanced titanium implant osseointegration.

Preventing bacterial infection and promoting osseointegration are essential for the long-term success of titanium (Ti) implants. In this study, we developed a multifunctional nanocoating on Ti mini-implants to simultaneously address these challenges. The nanocoating consists of self-assembled antimicrobial peptides GL13K and silver nanoparticles, referred to as Ag-GL.

Integration of RT-LAMP and Microfluidic Technology for Detection of SARS-CoV-2 in Wastewater as an Advanced Point-of-Care Platform.

Development of lab-on-a-chip (LOC) system based on integration of reverse transcription loop-mediated isothermal amplification (RT-LAMP) and microfluidic technology is expected to speed up SARS-CoV-2 diagnostics allowing early intervention. In the current work, reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and RT-LAMP assays were performed on extracted RNA of seven wastewater samples from COVID-19 hotspots. RT‑LAMP assay was also performed on wastewater samples without RNA extraction.

Plant-inspired TransfOrigami microfluidics.

The healthy functioning of the plants' vasculature depends on their ability to respond to environmental changes. In contrast, synthetic microfluidic systems have rarely demonstrated this environmental responsiveness. Plants respond to environmental stimuli through nastic movement, which inspires us to introduce transformable microfluidics: By embedding stimuli-responsive materials, the microfluidic device can respond to temperature, humidity, and light irradiance.

Co-doping optimized hydrogel-elastomer micro-actuators for versatile biomimetic motions.

Hydrogels can respond to changes in humidity or temperature, while elastomers can resist structural collapse due to dehydration or external force application. A hybrid bilayer of hydrogel-elastomers while retaining the merits of both the hydrogels and elastomers has emerged as a promising stimuli-responsive micro-actuator. However, the preparation of a hydrogel-elastomer micro-actuator requires multiple steps, mainly due to the differences in the surface properties of these two materials.

Interferon α2-Thymosin α1 Fusion Protein (IFNα2-Tα1): A Genetically Engineered Fusion Protein with Enhanced Anticancer and Antiviral Effect.

Human interferon α2 (IFNα2) and thymosin α1 (Tα1) are therapeutic proteins used for the treatment of viral infections and different types of cancer. Both IFNα2 and Tα1 show a synergic effect in their activities when used in combination. Furthermore, the therapeutic fusion proteins produced through the genetic fusion of two genes can exhibit several therapeutic functions in one molecule.

A portable droplet microfluidic device for cortisol measurements using a competitive heterogeneous assay.

Point-of-care monitoring of chemical biomarkers in real-time holds great potential in rapid disease diagnostics and precision medicine. However, monitoring is still rare in practice, as the measurement of biomarkers often requires time consuming and labour intensive assay procedures such as enzyme linked immunosorbent assay (ELISA), which pose a challenge to an autonomous point-of-care device. This paper describes a prototype device capable of performing ELISA autonomously and repeatedly in a high frequency using droplet microfluidics.

COVID-19 Crisis Creates Opportunity towards Global Monitoring & Surveillance.

The spectrum of emerging new diseases as well as re-emerging old diseases is broadening as infectious agents evolve, adapt, and spread at enormous speeds in response to changing ecosystems. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recent phenomenon and may take a while to understand its transmission routes from less traveled territories, ranging from fomite exposure routes to wastewater transmission. The critical challenge is how to negotiate with such catastrophic pandemics in high-income countries (HICs ~20% of the global population) and low-and middle-income countries (LMICs ~ 80% of the global population) with a total global population size of approximately eight billion, where practical mass testing and tracing is only a remote possibility, particularly in low-and middle-income countries (LMICs).

A Review of Biodegradable Natural Polymer-Based Nanoparticles for Drug Delivery Applications.

Biodegradable natural polymers have been investigated extensively as the best choice for encapsulation and delivery of drugs. The research has attracted remarkable attention in the pharmaceutical industry. The shortcomings of conventional dosage systems, along with modified and targeted drug delivery methods, are addressed by using polymers with improved bioavailability, biocompatibility, and lower toxicity.

Glycoprotein- and Lectin-Based Approaches for Detection of Pathogens.

Infectious diseases alone are estimated to result in approximately 40% of the 50 million total annual deaths globally. The importance of basic research in the control of emerging and re-emerging diseases cannot be overemphasized. However, new nanotechnology-based methodologies exploiting unique surface-located glycoproteins or their patterns can be exploited to detect pathogens at the point of use or on-site with high specificity and sensitivity.

Easily fabricated monolithic fluoropolymer chips for sensitive long-term absorbance measurement in droplet microfluidics.

Maintaining a hydrophobic channel surface is critical to ensuring long-term stable flow in droplet microfluidics. Monolithic fluoropolymer chips ensure robust and reliable droplet flow as their native fluorous surfaces naturally preferentially wet fluorocarbon oils and do not deteriorate over time. Their fabrication, however, typically requires expensive heated hydraulic presses that make them inaccessible to many laboratories.

Capillary-Driven Flow Microfluidics Combined with Smartphone Detection: An Emerging Tool for Point-of-Care Diagnostics.

Point-of-care (POC) or near-patient testing allows clinicians to accurately achieve real-time diagnostic results performed at or near to the patient site. The outlook of POC devices is to provide quicker analyses that can lead to well-informed clinical decisions and hence improve the health of patients at the point-of-need. Microfluidics plays an important role in the development of POC devices.

Design and Fabrication of Capillary-Driven Flow Device for Point-Of-Care Diagnostics.

Point-of-care (POC) diagnostics enables the diagnosis and monitoring of patients from the clinic or their home. Ideally, POC devices should be compact, portable and operatable without the requirement of expertise or complex fluid mechanical controls. This paper showcases a chip-and-dip device, which works on the principle of capillary-driven flow microfluidics and allows analytes' detection by multiple microchannels in a single microchip via smartphone imaging.

Design and Fabrication of Optical Flow Cell for Multiplex Detection of β-lactamase in Microchannels.

Miniaturized quantitative assays offer multiplexing capability in a microfluidic device for high-throughput applications such as antimicrobial resistance (AMR) studies. The detection of these multiple microchannels in a single microfluidic device becomes crucial for point-of-care (POC) testing and clinical diagnostics. This paper showcases an optical flow cell for detection of parallel microchannels in a microfluidic chip.

A Droplet Microfluidic-Based Sensor for Simultaneous in Situ Monitoring of Nitrate and Nitrite in Natural Waters.

Microfluidic-based chemical sensors take laboratory analytical protocols and miniaturize them into field-deployable systems for in situ monitoring of water chemistry. Here, we present a prototype nitrate/nitrite sensor based on droplet microfluidics that in contrast to standard (continuous phase) microfluidic sensors, treats water samples as discrete droplets contained within a flow of oil. The new sensor device can quantify the concentrations of nitrate and nitrite within each droplet and provides high measurement frequency and low fluid consumption.

Monitoring biomolecule concentrations in tissue using a wearable droplet microfluidic-based sensor.

Knowing how biomarker levels vary within biological fluids over time can produce valuable insight into tissue physiology and pathology, and could inform personalised clinical treatment. We describe here a wearable sensor for monitoring biomolecule levels that combines continuous fluid sampling with in situ analysis using wet-chemical assays (with the specific assay interchangeable depending on the target biomolecule). The microfluidic device employs a droplet flow regime to maximise the temporal response of the device, using a screw-driven push-pull peristaltic micropump to robustly produce nanolitre-sized droplets.

Micromachined optical flow cell for sensitive measurement of droplets in tubing.

Here a micromachined flow cell with enhanced optical sensitivity is presented that allows high-throughput analysis of microdroplets. As a droplet flows through multiple concatenated measurement points, the rate of enzymatic reaction in the droplet can be fully characterized without stopping the flow. Since there is no cross-talk between the droplets, the flow cell is capable of continuously measuring biochemical assays in a droplet flow and thus is suitable to be used for continuous point-of-care diagnostics monitoring.

Nitrate measurement in droplet flow: gas-mediated crosstalk and correction.

In droplet microfluidics, droplets have traditionally been considered discrete self-contained reaction chambers, however recent work has shown that dissolved solutes can transfer into the oil phase and migrate into neighbouring droplets under certain conditions. The majority of reports on such inter-droplet "crosstalk" have focused on surfactant-driven mechanisms, such as transport within micelles. While trialling a droplet-based system for quantifying nitrate in water, we encountered crosstalk driven by a very different mechanism: conversion of the analyte to a gaseous intermediate which subsequently diffused between droplets.

Phased peristaltic micropumping for continuous sampling and hardcoded droplet generation.

Droplet microfluidics has recently emerged as a new engineering tool for biochemical analysis of small sample volumes. Droplet generation is most commonly achieved by introducing aqueous and oil phases into a T-junction or a flow focusing channel geometry. This method produces droplets that are sensitive to changes in flow conditions and fluid composition.

Continuous measurement of enzymatic kinetics in droplet flow for point-of-care monitoring.

Droplet microfluidics is ideally suited to continuous biochemical analysis, requiring low sample volumes and offering high temporal resolution. Many biochemical assays are based on enzymatic reactions, the kinetics of which can be obtained by probing droplets at multiple points over time. Here we present a miniaturised multi-detector flow cell to analyse enzyme kinetics in droplets, with an example application of continuous glucose measurement.

Droplet interfaced parallel and quantitative microfluidic-based separations.

High-throughput, quantitative, and rapid microfluidic-based separations has been a long-sought goal for applications in proteomics, genomics, biomarker discovery, and clinical diagnostics. Using droplet-interfaced microchip electrophoresis (MCE) techniques, we have developed a novel parallel MCE platform, based on the concept of combining the Slipchip principle with a newly developed "Gelchip". The platform consists of two plastic plates, with droplet wells on one plate and separation channels with preloaded/cured gel in the other.