The use of biosensors in point‐of‐care (POC) testing devices has attracted considerable attention in the past few years, mainly because of their high specificity, portability, and relatively low cost. Coupling these devices with miniaturized electrochemical transducers has shown great potential toward simple, rapid, and cost‐effective analysis that can be performed in the field, especially for healthcare, environmental monitoring, and food quality control. For this reason, the number of publications in this field has grown exponentially over the past decade, making it a trending topic in current research. Although great improvement has been achieved in the field of electrochemical biosensing, there are still some challenges to overcome, especially concerning the improvement of sensing materials and miniaturization. In this Review, we summarize some of the most recent advances achieved in POC electrochemical biosensor applications, focusing on new materials and modifiers for biorecognition developed to improve sensitivity, specificity, stability, and response time.

Meeting the current needs for easier, more precise and faster analyses that also follow the principles of green analytical chemistry requires novel analytical chemistry strategies. Since the appearance in this century of the first device based on a paper platform, many studies have been presented in the literature, providing a wide range of designs and possibilities for the application of paper platforms to electroanalytical systems. This Review gives an overview of the field and can pave the way for the future development of electrochemical paper‐based analytical devices. We also present a critical point of view regarding what has been investigated and developed and what is still missing. This Review discusses the efforts made in the field related to important topics such as the choice of the paper substrate, the device construction process, the characterization of the device, and applications in different areas. In this way, we indicate some steps necessary for optimizing the design of the devices, with a focus on multidisciplinary collaborations that could move entire systems from the bench of the laboratory to the field.

This work describes the preparation of a glassy carbon electrode (GCE) modified with molecularly imprinted polymer (MIP) and multiwalled carbon nanotubes (MWCNTs) for determination of carvedilol (CAR). Electrochemical behavior of CAR on the modified electrode was evaluated using cyclic voltammetry. The best composition was found to be 65% (m/m) of MIP. Under optimized conditions (pH 8.5 in 0.25 mol·L −1 Britton-Robinson buffer and 0.1 mol·L −1 KCl) the voltammetric method showed a linear response for CAR in the range of 50-325 µmol·L −1 (R = 0.9755), with detection and quantification limits of 16.14 µmol·L −1 and 53.8 µmol·L −1 , respectively. The developed method was successfully applied for determination of CAR in real samples of pharmaceuticals. The sensor presented good sensitivity, rapid detection of CAR, and quick and easy preparation. Furthermore, the material used as modifier has a simple synthesis and its amount utilized is very small, thus illustrating the economic feasibility of this sensor.

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In the present paper a voltammetric sensor based on glassy carbon electrode (GCE) and cobalt phthalocyanine (CoPc)/multiwalled carbon nanotube (MWCNT) composite has been successfully prepared for uric acid (UA) determination in real samples. The electrochemical behavior of UA at the GCE‐CoPc/MWCNT has been evaluated by employing cyclic voltammetry. The charge transfer coefficient, α, and the charge transfer rate constant, κs, for electron transfer between CoPc/MWCNT and GCE were calculated as 0.49 and 19.5±0.51 s−1, respectively. Under optimized conditions (pH 7.0 in 0.10 mol L−1 phosphate buffer) the best technique was the square wave voltammetry and responds linearly to UA from 0.2 up to 1.0 mmol L−1 (r=0.997) and 1.25 up to 4.0 mmol L−1 (r=0.991) with limits of detection and quantification of 0.26 and 0.86 mmol L−1, respectively. The developed method was successfully applied for UA determination in real samples of human urine. The modified electrode exhibits sensitive and stable responses and does not show interferences in presence of dopamine and ascorbic acid.

In the present study the synthesis of a nanocomposite based on multi-walled carbon nanotubes grafted by poly(methacrylic acid–hemin) is described.

Uric acid (UA), a product of purine nucleotide degradation able to initiate an immune response, represents a breakpoint in the evolutionary history of humans, when uricase, the enzyme required for UA cleavage, was lost. Despite being inert in human cells, UA in its soluble form (sUA) can increase the level of interleukin-1β (IL-1β) in murine macrophages. We, therefore, hypothesized that the recognition of sUA is achieved by the Naip1-Nlrp3 inflammasome platform. Through structural modelling predictions and transcriptome and functional analyses, we found that murine Naip1 expression in human macrophages induces IL-1β expression, fatty acid production and an inflammation-related response upon sUA stimulation, a process reversed by the pharmacological and genetic inhibition of Nlrp3. Moreover, molecular interaction experiments showed that Naip1 directly recognizes sUA. Accordingly, Naip may be the sUA receptor lost through the human evolutionary process, and a better understanding of its recognition may lead to novel anti-hyperuricaemia therapies.

A SPR-based immunosensor was developed using a SAM of an alkanethiol associated with dendrimers PAMAM(G4) to enhance the sensitivity for troponin T detection in blood samples. The feasibility of using three-dimensional platforms based on dendrimers for the development of immunosensors was demonstrated by evaluating three different generations of these dendrimers (G3, G4, and G5) to detect troponin T.The results showed the efficiency of these 3D platforms in anchoring biomolecules, amplifying the detection of troponin T. The sandwich assay showed good performance for troponin T detection, using secondary monoclonal antibodies, in the concentration range of 5-300 ng mL −1 (0.14 -8.67 nmol L −1 ), R 2 =0.991, with a LOD of 3.6 ng mL −1 .The sandwich assay's applicability was demonstrated by evaluating a secondary polyclonal antibody's performance in the concentration range of 3-30 ng mL −1 , R 2 =0.998, with a LOD of 0.98 ng mL −1 . The immunosensor was applied to determine troponin T in blood plasma samples from healthy patients, with an average recovery of 88% to 104%. The performance of the SPR-based immunosensor indicates reliable results, contributing to the rapid diagnosis of heart attack, with reduced costs.