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As a significant and promising conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) has attracted considerable attention in the last decade. This review aims at giving a comprehensive illustration about current progress on the synthesis and electrochemical sensing applications of PEDOT-based materials in environmental monitoring, food and drug analysis and health care. PEDOT-based materials, such as PEDOT, functionalized PEDOT and PEDOT composites were fabricated mainly by chemical polymerization and electrochemical polymerization. Various nanostructures with large surface area, high conductivity, fast electron transfer rate, hydrophobic interaction and good biocompatibility were displayed by the PEDOT-based materials. Synergetic effects were enhanced dramatically in electrochemical (bio) sensors by PEDOT composites, especially by those incorporated with versatile nanomaterials. Through this paper, we hope to attract attention from a wider community and inspire researchers to take advantage of PEDOT in approaching scientific challenges and developments. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an electrochemical microsensor for simultaneous detection of copper (II) and lead (II) using an l-aspartic acid/l-cysteine/gold nanoparticle modified microelectrode. The microelectrode was fabricated by Micro Electro-Mechanical System technique. The complex of gold nanoparticles (AuNPs) and amino acid with carboxyl group was used as the selective ligand for metal ions. The microelectrode was firstly modified with AuNPs to increase the sensitive area of the working electrode. Subsequently, the AuNPs/gold electrode was modified with l-cysteine and then covalently linked with a monolayer of l-aspartic acid using glutaraldehyde. Electrochemical analysis of metal ions was achieved by using square wave voltammetry without stirring. The microsensor exhibited an excellent linear range from 5μgL−1 to 2000μgL−1 with the limit of detection of 1μgL−1. This metal ion detection method based on l-aspartic acid/l-cysteine/gold nanoparticle modified microelectrode is simple, sensitive and it could be used for electrochemical analysis of copper (II) and lead (II). [Copyright &y& Elsevier]

Abstract: A micro potentiometric immunosensor based on mixed SAMs wrapped nano-spheres array for the detection of hemoglobin-A1c level is presented in this paper. Nano-spheres array is prepared by wrapping nano-gold particle with mixed SAMs on the surface of micro immunosensor. Mixed SAMs make the nano-gold particles distribute uniformly without aggregation and render the signal less susceptible to noise. Based on this nano-spheres array, antibody is covalently immobilized on the immunosensor surface. The micro immunosensor, consisting of ISFET integrated chip and MEMS electrodes array is applied to measure hemoglobin-A1c level by detecting the concentration of hemoglobin-A1c and hemoglobin simultaneously. The responses of the immunosensor are linear over the concentration range of 166.7–570ng/ml hemoglobin and 50–170.5ng/ml HbA1c. Whole blood sample obtained from hospital was also examined using this immunosensor. The low relative deviation shows that this micro immunosensor may provide an alternative tool for the determination of HbA1c level. [ABSTRACT FROM AUTHOR]

Mercury ions (Hg 2 + ) pollution in the water environment can cause serious harm to human health. Trace Hg 2 + detection is of vital importance for environmental monitoring. Herein, we report a novel design of Ru-MOFs modified gold microelectrode for Hg 2 + determination. Ru-MOFs are synthesized directly by the cathodic method on gold microelectrode, with the covered area accurately controlled. Cathodic synthesized Ru-MOFs show good conductivity and are suitable to be used as the electrode surface material directly. The synergy of the pre-deposition process and the adsorption process of Ru-MOFs can effectively improves the performance of the sensor. The results show good linearity (R 2 = 0.996) from 0.1 ppb to 5 ppb, with a high sensitivity of 0.583 μ A ppb − 1 mm − 2 . The limit of detection is found to be 0.08 ppb and the test process is within 6 min. Most importantly, the senor has a good anti-interference ability and the recoveries are satisfactory. This miniature electrochemical sensor has the potential for on-site detection of trace mercury in the field. [ABSTRACT FROM AUTHOR]

Wearable sweat electrochemical sensors have attracted wide attention due to their advantages of non-invasive, portable, real-time monitoring, etc. However, existing sensors still have some problems with efficient sweat collection. Microfluidic channel technology and electrospinning technology are commonly used to collect sweat efficiently, but there are some limitations such as complex channel design and multiple spinning parameters. Besides, existing sensors are mostly based on flexible polymers, such as, PET, PDMS, PI and PI, which have limited wearability and permeability. Based on the above, all fabric and dual-function flexible wearable sweat electrochemical sensor is proposed in this paper. This sensor uses fabric as the raw material to implement the directional transport of sweat and the multi-component integrated detection dual functions. Meanwhile, the high-efficiency collection of sweat is obtained by a Janus fabric, wherein one side of the selected silk is superhydrophobic graft treated and the other side is hydrophilic plasma treated. Therefore, the resulting Janus fabric can effectively transfer sweat from the skin side to the electrode, and the minimum sweat droplet can reach 0.2 μL to achieve micro-volume collection. Besides, the patterned sensor, made of silk-based carbon cloth, is fabricated using a simple laser engraving, which could detect Na+, pH, and glucose instantaneously. As a result, these proposed sensors can achieve good sensing performance and high-efficiency sweat collection dual functionality; moreover, it has good flexibility and comfortable wearability. [Display omitted] • The flexible substrate, electrode and sweat collection layers are all made of fabric. • Full-fabric sweat sensors have good flexibility and wearability. • Full-fabric sweat sensors have the dual functions of sweat collection and detection. • Janus fabric can achieve micro-volume sweat collection of 0.2 μL. [ABSTRACT FROM AUTHOR]

This work mainly describes an electrochemical microsensor based on the reduction of molybdophosphate complex for total phosphorus (TP) determinations in water. The microelectrode was fabricated using microelectromechanical systems (MEMS) techniques and porous, branching gold nanoparticles (AuNPs) were electrodeposited on the microelectrode to improve its sensitivity. Calibration of the microsensor was performed with standard phosphate solutions prepared with KH2 PO4 with pH adjusted to 1.0. The experimental results showed that both sensitivity and current response are improved effectively using this modified microelectrodes: The limit of detection of the microsensor is 1.2 × 10−7 mol/l and linear range is 3 × 10−7 to 3 × 10−4 mol/l. The sensitivity of unmodified electrode is −0.27 nA/μmol·l−1 (R2 = 0.994), whereas the sensitivity of AuNPs modified electrode is −0.89 nA/μmol l−1 (R2 = 0.98). The current response of modified electrode is 6 times larger than that of unmodified electrode in average. Detection of TP was also carried out with digested TP standard solutions for both modified and unmodified electrodes, and results were consistent with the nominal value of phosphorus concentration. This microsensor provides the probability of combining TP detection device with micro‐digesting device to form a TP detection system, which can realise the automotive and on‐line monitoring of TP in surface water. [ABSTRACT FROM AUTHOR]