RESUMO

The development of miniaturized, sustainable and eco-friendly analytical sensors with low production cost is a current trend worldwide. Within this idea, this work presents  the innovative use of masked stereolithography (MSLA) 3D-printed substrates for the easy fabrication of pencil-drawn electrochemical sensors (MSLA-3D-PDE). The use of a non-toxic material such as pencil (electrodes) together with a biodegradable 3D printing resin (substrate) allowed the production of devices that are quite cheap (ca. US$ 0.11 per sensor) and with low environmental impact. Compared to paper, which is the most used substrate for manufacturing pencil-drawn electrodes, the MSLA-3D-printed substrate has the advantages of not absorbing water (hydrophobicity) or becoming crinkled and weakened when in contact with solutions. These features provide more reproducible, reliable, stable, and long-lasting sensors. The MSLA-3D-PDE, in conjunction with the custom cell developed, showed excellent robustness and electrochemical performance similar to that observed of the glassy carbon electrode, without the need of any activation procedure. The analytical applicability of this platform was explored through the quantification of omeprazole in pharmaceuticals. A limit of detection (LOD) of 0.72 µmol L-1 was achieved, with a linear range of 10 to 200 µmol L-1. Analysis of real samples provided results that were highly concordant with those obtained by UV-Vis spectrophotometry (relative error ≤ 1.50%). In addition, the greenness of this approach was evaluated and confirmed by a quantitative methodology (Eco-Scale index). Thus, the MSLA-3D-PDE appears as a new and sustainable tool with great potential of use in analytical electrochemistry.

RESUMO

This study evaluated the bioactivity of 3D-printed ß-tricalcium phosphate (ß-TCP) scaffolds or hydroxyapatite (HA) scaffolds associated with polydioxanone (PDO) membrane (Plenum® Guide) for guided bone regeneration in rats. Fifty-four rats were divided into three groups (n = 18 animals): autogenous bone + PDO membrane (Auto/PG); 3D-printed ß-TCP + PDO membrane (TCP/PG); and 3D-printed HA + PDO membrane (HA/PG). A surgical defect in the parietal bone was made and filled with the respective scaffolds and PDO membrane. The animals were euthanized 7, 30, and 60 days after the surgical procedure for micro-CT, histomorphometric, and immunolabeling analyses. Micro-CT showed an increase in trabecular thickness and a decrease in trabecular separation, even with similar bone volume percentages between TCP/PG and HA/PG vs. Auto/PG. Histometric analysis showed increased bone formation at 30 days in the groups compared to 7 days postoperatively. Immunolabeling analysis showed an increase in proteins related to bone formation at 30 days, and both groups showed a similar immunolabeling pattern. This study concludes that 3D-printed scaffolds associated with PDO membrane (Plenum® Guide) present similar results to autogenous bone for bone regeneration.

RESUMO

This communication shows the electrochemical synthesis of Prussian blue (PB) films on additive manufactured (3D-printed) electrodes from iron impurities found at the graphene-polylactic acid (G/PLA) substrate and its application as a highly selective sensor for H2O2. The 3D-printed G/PLA electrode was immersed in dimethylformamide for 30 min to exposure the iron impurities within the PLA matrix. Next, cyclic voltammograms (200 cycles) in the presence of potassium ferricyanide in 0.1 mol L-1 KCl + 0.01 mol L-1 HCl were performed to grow the PB films. The sensing properties of this novel PB/G/PLA platform were evaluated for the amperometric detection of H2O2 using batch-injection analysis, with a limit of detection of 0.56 µmol L-1 under the application of 0.0 V (vs Ag/AgCl/KClsat.). The applicability of the sensor was demonstrated for the analysis of milk samples (10-fold diluted in the supporting electrolyte), resulting in proper recovery values (94-101%).

Assuntos

Grafite , Peróxido de Hidrogênio , Eletrodos , Ferrocianetos , Ferro , Impressão Tridimensional

RESUMO

Additive manufacturing or three-dimensional (3D)-printing is an emerging technology that has been applied in the development of novel materials and devices for a wide range of applications, including Electrochemistry and Analytical Chemistry areas. This review article focuses on the contributions of 3D-printing technology to the development of electrochemical sensors and complete electrochemical sensing devices. Due to the recent contributions of 3D-printing within this scenario, the aim of this review is to present a guide for new users of 3D-printing technology considering the required features for improved electrochemical sensing using 3D-printed sensors. At the same time, this is a comprehensive review that includes most 3D-printed electrochemical sensors and devices already reported using selective laser melting (SLM) and fused deposition modeling (FDM) 3D-printers. The latter is the most affordable 3D-printing technique and for this reason has been more often applied for the fabrication of electrochemical sensors, also due to commercially-available conductive and non-conductive filaments. Special attention is given to critically discuss the need for the surface treatment of FDM 3D-printed platforms to improve their electrochemical performance. The insertion of biochemical and chemical catalysts on the 3D-printed surfaces are highlighted as well as novel strategies to fabricate filaments containing chemical modifiers within the polymeric matrix. Some examples of complete electrochemical sensing systems obtained by 3D-printing have successfully demonstrated the enormous potential to develop portable devices for on-site applications. The freedom of design enabled by 3D-printing opens many possibilities of forthcoming investigations in the area of analytical electrochemistry.