Microbe-Based Sensor for Long-Term Detection of Urine Glucose.

The development of a reusable and low-cost urine glucose sensor can benefit the screening and control of diabetes mellitus. This study focused on the feasibility of employing microbial fuel cells (MFC) as a selective glucose sensor for continuous monitoring of glucose levels in human urine. Using MFC technology, a novel cylinder sensor (CS) was developed. It had a quick response time (100 s), a large detection range (0.3-5 mM), and excellent accuracy. More importantly, the CS could last for up to 5 months. The selectivity of the CS was validated by both synthetic and actual diabetes-negative urine samples. It was found that the CS's selectivity could be significantly enhanced by adjusting the concentration of the culture's organic matter. The CS results were comparable to those of a commercial glucose meter (recovery ranged from 93.6% to 127.9%) when the diabetes-positive urine samples were tested. Due to the multiple advantages of high stability, low cost, and high sensitivity over urine test strips, the CS provides a novel and reliable approach for continuous monitoring of urine glucose, which will benefit diabetes assessment and control.

Photoluminescent, "ice-cream cone" like Cu-In-(Zn)-S/ZnS nanoheterostructures.

Copper based ternary and quaternary quantum confined nanostructures have attracted huge attention over recent years due to their potential applications in photonics, photovoltaics, imaging, sensing and other areas. However, anisotropic nanoheterostructures of this type are still poorly explored to date, despite numerous predictions of the distinctive optical properties of these highly fluorescent heavy metal free nanostructures. Here, we report new fluorescent multicomponent Cu-In-(Zn)-S/ZnS nanoheterostructures with a unique anisotropic "ice-cream cone" like morphology. These nanostructures have been prepared with a seeded growth technique and exhibit distinct photophysical properties with maximum emission in the visible range (≈ 640 nm) and long photoluminescence lifetimes (τaverage ≥ 300 ns). In depth time interval studies have been carried out to better understand the step by step growth mechanism of this distinct "ice-cream cone" like geometry. We have demonstrated that the crystal structure evolution from the zinc blende Cu-In-S core to the wurtzite "ice cream cone" like Cu-In-(Zn)-S/ZnS nanocrystals plays a key role in the origin of this morphology. This research opens new possibilities to produce unique fluorescent Cu-based multicomponent anisotropic heteronanostructures, while also offering a distinctive insight into the design of bespoke nanostructures, which could find a range of potential applications.

Sampling, Identification and Characterization of Microplastics Release from Polypropylene Baby Feeding Bottle during Daily Use.

Microplastics (MPs) are becoming a global concern due to the potential risk to human health. Case studies of plastic products (i.e., plastic single-use cups and kettles) indicate that MP release during daily use can be extremely high. Precisely determining the MP release level is a crucial step to identify and quantify the exposure source and assess/control the corresponding risks stemming from this exposure. Though protocols for measuring MP levels in marine or freshwater has been well developed, the conditions experienced by household plastic products can vary widely. Many plastic products are exposed to frequent high temperatures (up to 100 °C) and are cooled back to room temperature during daily use. It is therefore crucial to develop a sampling protocol that mimics the actual daily-use scenario for each particular product. This study focused on widely used polypropylene-based baby feeding bottles to develop a cost-effective protocol for MP release studies of many plastic products. The protocol developed here enables: 1) prevention of the potential contamination during sampling and detection; 2) realistic implementation of daily-use scenarios and accurate collection of the MPs released from baby feeding bottles based on WHO guidelines; and 3) cost-effective chemical determination and physical topography mapping of MPs released from baby feeding bottles. Based on this protocol, the recovery percentage using standard polystyrene MP (diameter of 2 µm) was 92.4-101.2% while the detected size was around 102.2% of the designed size. The protocol detailed here provides a reliable and cost-effective method for MP sample preparation and detection, which can substantially benefit future studies of MP release from plastic products.

Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation.

Polypropylene-based products are commonly used for food preparation and storage, but their capacity to release microplastics is poorly understood. We investigated the potential exposure of infants to microplastics from consuming formula prepared in polypropylene (PP) infant feeding bottles (IFBs). Here, we show that PP IFBs release microplastics with values as high as 16,200,000 particles per litre. Scenario studies showed that PP IFB sterilization and exposure to high-temperature water significantly increase microplastic release. A 21-d test of PP IFBs showed periodic fluctuations in microplastic release. To estimate the potential global exposure to infants up to 12 months old, we surveyed 48 regions, finding values ranging from 14,600-4,550,000 particles per capita per day, depending on the region. We demonstrate that infant exposure to microplastics is higher than was previously recognized due to the prevalence of PP-based products used in formula preparation and highlight an urgent need to assess whether exposure to microplastics at these levels poses a risk to infant health.

Tunable synthesis of ultrathin AuAg nanowires and their catalytic applications.

Metallic nanowires (NWs) are very interesting and important nanomaterials with unique properties and a number of potential applications. Herein we report a tunable synthesis of water soluble ultrathin AuAg NWs. By using TEM and UV-vis spectroscopy, we demonstrate that these NWs can be produced by a new two-step process, which involves the formation of NW templates during the aging period and the subsequent formation of thicker NWs by a solvent driven fusion and wetting process. Our control studies further show that silver concentration plays a key role in the formation of these nanowires. We also demonstrate that these nanowires can effectively catalyse the reduction of 4-nitrophenol to the corresponding 4-aminophenol. Interestingly, the larger diameter ultrathin nanowires (av. 8 nm) exhibit a greater catalytic performance than the thinner nanowires (av. 3 nm). We believe that these studies are important for further development of one dimensional metal based nanomaterials, which may find a range of potential research and technological applications.

Pt and RhPt dendritic nanowires and their potential application as anodic catalysts for fuel cells.

Fuel cells have a number of benefits over conventional combustion-based technologies and can be used in a range of important applications, including transportation, as well as stationary, portable and emergency backup power systems. One of the major challenges in this field, however lies in controlling catalyst design which is critical for developing efficient and cost-effective fuel cell technology. Herein, for the first time, we report a facile controlled synthesis of Pt and RhPt dendritic nanowires using ultrathin AuAg nanowires as sacrificial templates. These dendritic nanowires exhibit remarkable catalytic performance in the elecrochemical oxidation of methanol and formic acid. In particular, the RhPt dendritic nanostructures show very high resistance to catalyst poisoning in methanol oxidation. This research demonstrates the advantages of using bimetallic dendritic nanostructures and we believe that these materials and electrocatalytic studies are important for further advancement of fuel cell research and technology.