Nano- and Microstructured Copper/Copper Oxide Composites on Laser-Induced Carbon for Enzyme-Free Glucose Sensors

Abstract

Low-cost enzyme-free glucose sensors with partial flexibility adaptable for wearable Internet of Things devices that can be envisioned as personalized point-of-care devices were produced by electroplating copper on locally carbonized flexible meta-polyaramid (Nomex) sheets using laser radiation. Freestanding films were annealed in nitrogen and nitrogen/air working environments, leading to the formation of Cu microspheroids and CuO urchins dispersed on the substrate film. The aggregation mechanism, crystallographic properties, surface chemistry, and electrochemical properties of the films were studied using scanning electron microscopy, X-ray diffractometry, transmission electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry. Cu microspheroids and CuO urchins attained activity for glucose detection and showed improvement of amperometric sensitivity to 0.25 and 0.32 mA cm −2 mM −1 , respectively. The CuO urchin film retained its chemical composition after amperometric testing, and, by rinsing, allowed multiple repetitions with reproducible results. This study opens the possibility for the fabrication of durable composite biosensors with tailored shape, capable of implementation in flexible carriers, and microfluidic systems.

Recent advances in optical sensors for continuous glucose monitoring

“…explored [54,61]. Nanoscale metal oxide materials differ dramatically from their bulk counterparts in terms of their properties.…”

“…Also, the fabrication is cost-effective and straightforward, along with enhanced surface area and higher crystallinity, which contributes to higher sensitivity towards glucose sensing [62]. For example, recently, a cost-effective glucose sensor based on electroplated copper using laser radiation on top of carbonated flexible meta-polyaramid has been reported [61]. Later, these films were annealed in an ambient environment, resulting in dispersed CuO urchins and Cu microspheroids.…”

“…62 For example, recently, a cost-effective glucose sensor based on electroplated copper using laser radiation on top of carbonated flexible meta-polyaramid has been reported. 61 Later, these films were annealed in an ambient environment, resulting in dispersed CuO urchins and Cu microspheroids. A higher sensitivity of Cu/CuO micro-nanostructures was found towards glucose.…”

Copper(II) Oxide Nanoparticles Embedded within a PEDOT Matrix for Hydrogen Peroxide Electrochemical Sensing

“…Copper(II) oxide is particularly interesting in electrochemistry due to its nontoxic character, high stability, and semiconducting properties ( p -type semiconductor), with a narrow band gap (ca. 1.2 eV) and high reactivity in electrocatalytic reactions (one–two electron pathway) at low potential toward clinically relevant analytes such as glucose, uric acid, dopamine, and ascorbic acid [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. By taking advantage of soft chemistry approaches, such as hydro-/solvothermal methods [ 21 , 22 , 23 , 24 , 25 ], microwave procedures [ 26 , 27 , 28 ], and/or polyol-assisted synthesis [ 2 , 29 , 30 , 31 , 32 ], nanoscaled CuOs with diverse morphologies (nano-spheres, nanowires [ 7 , 33 ], rectangular-shaped nanobat- [ 22 ], urchin- [ 24 , 26 ], flake-, leaf- or flower-like [ 28 ] structures) were obtained.…”

Fabrication of High Surface Area Microporous ZnO from ZnO/Carbon Sacrificial Composite Monolith Template

“…Porous nanomaterials have gained significant interest and are being studied extensively in this respect [15,16]. The unique microstructures of those porous materials have engrossed considerable attention as a functional material owing to their variety and better performance during applications in the area of catalysis [17], photocatalysis [18], separation [19], adsorption [20], energy storage and conversion [21], and sensing to physicochemical devices [22][23][24] in recent years. These materials are usually characterized for their porosity at macro-, meso-, and microscale, uniformity of pores, hierarchy and interconnection between each level of porosity, large accessible high surface areas, low density and excellent accommodation capability of other nanomaterials into the pore volumes, which enables the easy transport of ion/electron/reactant and the diffusion of mass, exposing boundless significance in applications requiring high accessible surface for reactions such as the energy density, rate capacity and cycling life in energy storage and modulation of electronic activities for sensing [25,26].…”