Biochar is a carbonaceous material that exhibits rich surface functional groups, which makes its use as a modifier of electrodes a very attractive alternative, especially the preconcentration of ...species of interest, organic or inorganic. This capability can be enhanced by activation of the material that increases the amount of functional groups, hence the ability to preconcentrate more species. In this study we used a carbon paste electrode modified with biochar activated with nitric acid for spontaneous preconcentration of Methyl Parathion and for further quantitative determination in drinking water. The electrode showed good sensitivity and limits of detection of MP, 760μALmmol−1, 39.0nmolL−1, respectively. Good accuracy of the method to determine MP in tap water samples was observed with recoveries values varying between 102 and 110% for three different concentration levels.
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•Use of activated biochar as new electrode modifier for determination of methyl parathion in aqueous samples•Alternative electrochemical sensor for methyl parathion determination•A simple chemical route to improve the adsorption ability of biochar towards methyl parathion•Morphological and structural characterization of surface proprieties of treated and untreated biochar
The development of new materials for electrochemical sensors has been received attention due to the search for sustainability. However, the use of
in natura
materials from vegetable and animal origin ...is still little explored for this purpose. Therefore, this work aims to use beeswax as biofilm, as an environmentally friendly and sustainable platform for incorporating carbon black nanoparticles. The electrode was prepared by a simple dispersion of beeswax and carbon black on the surface of the glassy carbon electrode. The proposed modified electrode was used to determine the herbicide paraquat (PQ) in 3 different samples of
Apis mellifera
honey. The presence of carbon black decreases the electrical resistance when compared with the bare electrode. The beeswax-carbon black film considerably increased the sensitivity of the PQ determination measures at a concentration range between 5.0 × 10
−7
and 7.5 × 10
−6
mol L
−1
. Samples with PQ contents between 7.5 × 10
−7
and 7.5 × 10
−6
mol L
−1
presented recovery values from 97.2 to 114%. Also, the proposed sensor showed good repeatability and reproducibility for successive measurements. This suggests the use of the proposed electrode is feasible as an alternative strategy in the monitoring of herbicides in honey samples.
Honey samples have been widely evaluated regarding the presence of degradation products as an index quality control, for example, hydroxymethylfurfural (HMF) in the presence of carbohydrates. The ...monitoring of HMF strategy can be a challenge; however, catalyst-based electroanalytical approaches can overcome it. This work aims the use of propolis to promote the anchoring of carbon nanotubes and Ni
2+
onto the electrode surface, as well as the synthesis of nickel oxyhydroxide. The modified electrode was applied as an electrochemical sensor in the determination of HMF and total carbohydrates, and the quantification of HMF in honey samples. The sensor has shown high sensitivity to successive additions of the evaluated species, presenting LOD of 0.18 and 0.051 mmol L
−1
for HMF and total carbohydrates, respectively. In the analyses of honey samples, recovery values between 91.8 and 107% of HMF were achieved. Therefore, the proposed modified sensor showed potential for use as a greener alternative for honey quality control.
Graphical abstract
The demand for new devices that enable the detection of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) at a relatively low cost and that are fast and feasible to be used as ...point-of-care is required overtime on a large scale. In this sense, the use of sustainable materials, for example, the bio-based poly (ethylene terephthalate) (Bio-PET) can be an alternative to current standard diagnostics. In this work, we present a flexible disposable printed electrode based on a platinum thin film on Bio-PET as a substrate for the development of a sensor and immunosensor for the monitoring of COVID-19 biomarkers, by the detection of L-cysteine and the SARS-CoV-2 spike protein, respectively. The electrode was applied in conjunction with 3D printing technology to generate a portable and easy-to-analyze device with a low sample volume. For the L-cysteine determination, chronoamperometry was used, which achieved two linear dynamic ranges (LDR) of 3.98-39.0 μmol L
and 39.0-145 μmol L
, and a limit of detection (LOD) of 0.70 μmol L
. The detection of the SARS-CoV-2 spike protein was achieved by both square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) by a label-free immunosensor, using potassium ferro-ferricyanide solution as the electrochemical probe. An LDR of 0.70-7.0 and 1.0-30 pmol L
, with an LOD of 0.70 and 1.0 pmol L
were obtained by SWV and EIS, respectively. As a proof of concept, the immunosensor was successfully applied for the detection of the SARS-CoV-2 spike protein in enriched synthetic saliva samples, which demonstrates the potential of using the proposed sensor as an alternative platform for the diagnosis of COVID-19 in the future.
This review aims to provide an overview of sustainable approaches that can be incorporated into well‐known procedures for the development of materials, pre‐ and post‐treatments, modifications, and ...applications of 3D‐printed objects, especially for fused filament fabrication (FFF). Different examples of conductive and non‐conductive bespoke filaments using renewable biopolymers, bioplasticizers, and recycled materials are presented and discussed. The main final characteristics of the polymeric materials achieved according to the feedstock, preparation, extrusion, and treatments are also covered. In addition to recycling and remanufacturing, this review also explores other alternative approaches that can be adopted to enhance the sustainability of methods, aiming to produce efficient and environmentally friendly 3D printed products. Adjusting printing parameters and miniaturizing systems are also highlighted in this regard. All these recommended strategies are employed to minimize environmental damage, while also enabling the production of high‐quality, economical materials and 3D printed systems. These efforts align with the principles of Green Chemistry, Sustainable Development Goals (SDGs), 3Rs (Reduce, Reuse, Recycle), and Circular Economy concepts.
This review provides an overview of sustainable approaches that can be incorporated into well‐known procedures for the development of materials, pre‐ and post‐treatments, modifications, adjustments, and applications of 3D‐printed objects, especially for fused filament fabrication (FFF). All these strategies can minimize environmental damage, while also enabling the production of high‐quality, economical materials, and 3D‐printed systems.
Advances in the use of 3D printing technology have led to the development of new low-cost devices. This technology features high versatility, considering the easy modulation of the materials ...depending on its objectives and applications. In this sense, we have developed a laboratory-built contact angle measuring device (lab-made). The device was composed by the assembly of 26 3D-printed pieces of different sizes and design printed using acrylonitrile-butadiene-styrene polymer. The device was designed in three main parts. The first part was related to the analysis, with the use of platforms for the sample surfaces positioning. The second part was made to support a micropipette, prepared to add the drop for analysis; and the third for the support of a smartphone, utilized to obtain the images. The device was applied for the measurement of contact angle on different surfaces, demonstrating its versatility and precision of the results. The obtained values are in accordance with others found in the literature. The developed device presented a low-cost (US$ 25.34 per device), easy assembly and operation.
Herein, we present the first 3D-printed electrochemical portable biodevice for the detection of monkeypox virus (MKPV). The electrochemical device consists of two biosensors: an immunosensor and a ...genosensor specifically designed for the detection of the protein A29 and a target DNA of MKPV, respectively. The electrodes were manufactured using lab-made ultraflexible conductive filaments composed of carbon black, recycled PLA from coffee pods, and castor oil as a plasticizer. The sensors created through 3D printing technology exhibited good reproducibility and repeatability of analytical responses. Furthermore, both the immunosensor and genosensor demonstrated excellent MKPV detection capabilities, with a linear range from 0.01 to 1.0 μmol L–1 for the antigen and 0.1 to 20.0 μmol L–1 for the DNA target. The biosensors achieved limits of detection of 2.7 and 29 nmol L–1 for the immunosensor and genosensor, respectively. Interference tests conducted with the biosensors demonstrated their selectivity for MKPV. Moreover, analyses of fortified human serum samples showed recoveries close to 100%, confirming the absence of significant matrix effects for MKPV analysis. Therefore, the 3D-printed multiplex device represents a viable and highly promising alternative for on-site, portable, and rapid point-of-care MKPV monitoring.
This work presents a new additive manufacturing electrochemical device with conductive graphene and polylactic acid (PLA) filament and its application for epinephrine sensing. A three-electrode ...configuration based on a screen-printed electrode architecture and an easy-to-connect connector was designed. The sensor surface was chemically treated with dimethylformamide (DMF) to remove the insulating thermoplastic and expose the graphene binding groups. The scanning electron microscopy (SEM) results showed that the surface PLA was removed and the graphene nanofibers exposed, which corroborated the X-ray diffraction spectra (XRD). As a proof of concept, the G-PLA electrode was applied for the determination of epinephrine in human blood samples by square wave voltammetry with a linear range from 4.0 to 100 µmol L−1 and a limit of detection of 0.2 µmol L−1. Based on the results obtained and sensor application, 3D-printed G-PLA proved an excellent choice for epinephrine sensing purposes.
3D printing technology is a strategic tool for the development of electrochemical sensors and biosensors since it is possible to obtain versatile devices quickly and at a low cost. In this work, an ...arrangement of 3D-printed electrodes (working, pseudo-reference, and auxiliary) was applied for the detection of PARK7/DJ-1 protein in blood serum and cerebrospinal fluid samples. The immunosensor surface was previously chemically and electrochemically activated to promote the increase of the active sites and the conductivity, allowing the covalent immobilization of the biological species (antibodies) and improving its electrochemical performance. The detection was carried out by impedimetric (5.0 −200 µg L−1), and voltammetric measurements (5.0 −500 µg L−1), showing limits of detection of 1.01 and 3.46 µg L−1. The 3D-printed immunosensor also achieved good repeatability and reproducibility from normal to abnormal levels of PARK7/DJ-1 protein, aiming for the diagnosis of Parkinson’s disease in different stages of the disease.
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•3D-printed immunosensor based on PLA and graphene filament was constructed.•Antibodies were stable immobilized on 3D printed electrodes.•3D-printed sensors arrangement was used for the sensing of PARK7/DJ-1 protein.•Feasible and low-cost immunosensor for the diagnosis of Parkinson’s disease.
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