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This work illustrates the development of a low-cost wireless sensor tag that could be placed in packaged medical products to accurately monitor the level of radiation exposure during the sterilization process.

Here we report a simple approach to increase the stability performance of all-solid-state electrochemical sensors by improving the interfacial bonding between the ion selective membrane and electrode through cold atmospheric plasma surface treatment.

Copper oxide nanostructures are widely used for various applications due to their unique optical and electrical properties. In this work, we demonstrate an atmospheric laser-induced oxidation technique for the fabrication of highly electrochemically active copper oxide hierarchical micro/nano structures on copper surfaces to achieve highly sensitive non-enzymatic glucose sensing performance. The effect of laser processing power on the composition, crystallinity, microstructure, wettability, and color of the laser-induced oxide on copper (LIO-Cu) surface was systematically studied using scanning electron microscopy (SEM), grazing incidence X-ray diffraction (GI-XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), EDX-mapping, water contact angle measurements, and optical microscopy. Results of these investigations showed a remarkable increase in copper oxide composition by increasing the laser processing power. The pore size distribution and surface area of the pristine and LIO-Cu sample estimated by N2 adsorption–desorption data showed a developed mesoporous LIO-Cu structure. The size of the generated nano-oxides, crystallinity, and electroactivity of the LIO-Cu were observed to be adjustable by the laser processing power. The electrocatalytic activity of LIO-Cu surfaces was studied by means of cyclic voltammetry (CV) within a potential window of −0.8 to +0.8 V and chronoamperometry in an applied optimized potential of +0.6 V, in 0.1 M NaOH solution and phosphate buffer solution (PBS), respectively. LIO-Cu surfaces with optimized laser processing powers exhibited a sensitivity of 6950 μA mM−1 cm−2 within a wide linear range from 0.01 to 5 mM, with exceptional specificity and response time (

Extracellular matrix (ECM) mechanical stiffness and its dynamic change is one of the main cues that directly affects the differentiation and proliferation of normal cells as well as the progression of disease processes such as fibrosis and cancer. Recent advancements in biomaterials have enabled a wide range of polymer matrices that could mimic the ECM of different tissues for a wide range of in vitro basic research and drug discovery. However, most of the technologies utilized to quantify the stiffness of such ECM are either destructive or expensive, and therefore are unsuitable for the in situ, long-term monitoring of variations in ECM stiffness for on-chip cell culture applications. This work demonstrates a novel noninvasive on-chip platform for characterization of ECM stiffness in vitro, by monitoring ultrasonic wave attenuation through the targeted material. The device is composed of a pair of millimeter scale ultrasonic transmitter and receiver transducers with the test medium placed in between them. The transmitter generates an ultrasonic wave that propagates through the material, triggers the piezoelectric receiver and generates a corresponding electrical signal. The characterization reveals a linear (r2 = 0.86) decrease in the output voltage of the piezoelectric receiver with an average sensitivity of -15.86 μV kPa-1 by increasing the stiffnesses of hydrogels (from 4.3 kPa to 308 kPa made with various dry-weight concentrations of agarose and gelatin). The ultrasonic stiffness sensing is also demonstrated to successfully monitor dynamic changes in a simulated in vitro tissue by gradually changing the polymerization density of an agarose gel, as a proof-of-concept towards future use for 3D cell culture and drug screening. In situ long-term ultrasonic signal stability and thermal assessment of the device demonstrates its high robust performance even after two days of continuous operation, with negligible (

Gut microbiota plays an important role in host physiology such as obesity, diabetes, and various neurological diseases. Thus, microbiome sampling is a fundamental approach towards better understanding of possible diseases. However, conventional sampling methods, such as endoscopies or colonoscopies, are invasive and cannot reach the entire small intestine. To address this need, a battery-less 3D-printed sampling capsule, which can collect microbiome samples throughout the entirety of the GI tract was designed. The capsule (9 mm × 15 mm) consists of a 3D printed acrylic housing, a fast-absorbing hydrogel, and a flexible PDMS membrane. Fluids containing samples of the microbial flora within the GI tract enter the device through a sampling aperture on the cap of the device. Once the microbiome enters the housing, the hydrogel absorbs the fluid and swells, effectively protecting the samples within its polymeric matrix, while also pushing on the flexible PDMS membrane to block the sampling aperture from further fluid exchange. The retrieved capsule can be readily disassembled due to the screw-cap design of the capsule and the hydrogel can be removed for further bacterial culture and analysis. As a proof of concept, the capsule's bacterial sampling efficiency and the ability to host microbial samples within the hydrogel in a sealed capsule were validated using a liquid culture containing Escherichia coli. The demonstrated technology provides a promising inexpensive tool for direct sampling and assessment of microbes throughout the GI tract and can enable new insights into the role of diet in mediating host–microbe interactions and metabolism.

This work presents a low-cost, passive, flexible, polymeric pump for topical drug delivery which uses wound pH as a trigger for localized drug release. Its operation relies on a pH-responsive hydrogel actuator which swells when exposed to the alkaline pH of an infected wound. The pump enables slow release (

A novel and flexible oxygen sensing patch was successfully developed for wearable, industrial, food packaging, pharmaceutical and biomedical applications using a cost-efficient and rapid prototypable additive inkjet print manufacturing process. An oxygen sensitive ink was formulated by dissolving ruthenium dye and ethyl cellulose polymer in ethanol in a 1 : 1 : 98 (w/w/w) ratio. The patch was fabricated by depositing the oxygen sensitive ink on a flexible parchment paper substrate using an inkjet printing process. A maximum absorbance from 430 nm to 480 nm and a fluorescence of 600 nm was observed for the oxygen sensitive ink. The capability of the oxygen sensitive patch was investigated by measuring the fluorescence quenching lifetime of the printed dye for varying oxygen concentration levels. A fluorescence lifetime decay (τ) from ≈4 μs to ≈1.9 μs was calculated for the printed oxygen sensor patch, for oxygen concentrations varying from ≈5 mg L−1 to ≈25 mg L−1. A sensitivity of 0.11 μs mg L−1 and a correlation coefficient of 0.9315 was measured for the printed patches. The results demonstrated the feasibility of employing an inkjet printing process for the rapid prototyping of flexible and moisture resistant oxygen sensitive patches which facilitates a non-invasive method for monitoring oxygen and its concentration levels.

Phosphate is one of the main nutrients playing many key roles in the human body and plant growth. Because of this essential demand, phosphate is often used as a micronutrient additive in both fertilizers and dietary supplements. However, its excessive amount could result in severe health issues in the human body and the ecosystem of aquatic life. Therefore, there is a need for an inexpensive rapid measurement approach that could assess the optimum level of phosphate by using simple low-cost sensors. Here, for the first time, we demonstrate the use of a nickel oxide modified screen printed carbon (PrC) electrode as a low-cost electrochemical potentiometric phosphate detection sensor. The nickel oxide/oxyhydroxide (NiO/NiOOH)-PrC electrode has been prepared by a facile anodic electrodeposition process onto a screen printed carbon electrode. The characterization performed by field emission scanning electron microscopy (FE-SEM) and energy diffractive X-ray spectroscopy (EDS) techniques confirmed the formation of NiO/NiOOH by significant changes in surface morphology and elemental composition of PrC after electrodeposition. The results exhibited a porous deposited layer containing nickel and an increased oxygen value of the modified electrode as compared to pristine PrC. Potentiometric phosphate detection on the NiO/NiOOH-PrC electrode showed a linear response in the concentration range of 10−6–10−1 M, yielding a slope of −78.48 mV per decade with a fast response time. The electrode demonstrated a stable response with less than 0.8% variability of the recorded potential over 2000 seconds. High durability and reusability of the electrode were confirmed by repeated potentiometric phosphate determination tests over a course of 21 days. Interference tests with chloride, nitrate, sulfate, bromide, acetate, and carbonate solutions revealed very low selectivity coefficients within the range of 10−11–10−2, which indicated a high phosphate-selectivity of the developed sensor. This novel technology provides great potential for future scalable production and applications in portable real-time monitoring of phosphate ions in different precision agricultural and point-of-care diagnostic applications.

We demonstrate, for the first time, a facile and low-cost approach for integrating highly flexible and stretchable microfluidic channels into textile-based substrates. The integration of the microfluidics is accomplished by means of directly embroidering surface-functionalized micro-tubing in a zigzag/meander pattern and subsequently coating it with an elastomer for irreversible bonding. We show the utility of the embroidered micro-tubing by developing robust and stretchable drug-delivery and electronic devices. Controlled drug-delivery platforms with sustained release are achieved through selected laser ablated openings. We further demonstrate a wearable wireless resonant displacement sensor capable of detecting strains ranging from 0 to 60% with an average sensitivity of 45 kHz per % strain by filling the embroidered tubing with a liquid metal alloy, creating stretchable conductive microfluidics with