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Porous polymeric scaffolds provide a physical substrate for cells to attach and proliferate, allowing the formation of new tissue. These materials are broadly used in the tissue engineering field due to their ability to mimic native tissue. Each application requires specific morphologies and resistance, among other several features. To accomplish these requirements, various techniques are available, each one with its advantages and disadvantages. Among the most relevant techniques are salt leaching, solvent casting, gas foaming, thermally induced phase separation, freeze-drying, electrospinning, thermally induced self-agglomeration, and three-dimensional (3D) printing. In this review, a brief and simple explanation of each method is described, along with some recent results and each technique's advantages and disadvantages. It is expected that this review will bring important guidance in the production of polymer scaffolds for tissue engineering.

A flexible sensor based on polymer poly (butylene adipate-co-terephthalate) (PBAT) mixed with graphite was surface modified with AuNP (gold nanoparticule) and copper phthalocyanine using Layer-by-Layer (LbL) technique for simultaneous determination of catechol (CC) and paraquat (PQ). The device with and without modification was characterized by contact angle, scanning electron microscopy, and Fourier transform infrared spectroscopy. Electrochemical characterization was performed by cyclic voltammetry and electrochemical impedance spectroscopy. A differential pulse voltammetry technique was used to detect CC and PQ molecules in an interval of 100 to 200 µM, some parameters were obtained from the analytical curve, such as linear regression values (R²) equal to 0.9998 and 0.9993 and detection limit (LOD) equal to 1.36 and 1.31 x 10-6 for CC and PQ, respectively. The sensor (g-PBAT/AuNP-PAH/CuTsPc)3 presented good stability, reproducibility, and repeatability, with recovery values ranging between 98.4 - 105.6% for CC and 94.4 - 106.1% for PQ when the sensor was subjected to analysis of samples contaminated with tap water. Electrodes produced in this work had the advantage of being flexible, disposable, reproducible and of low manufacturing cost, which makes them attractive for portable environmental analysis.

There is interest in obtaining alternative materials for application in electrochemical sensing. Thermoplastic starch (TPS) was used because it is a polymer with high availability and biodegradability, which can be incorporated into graphite (Gr) forming a conductive material. This work describes the characterization of the material produced by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), contact angle, x-ray diffraction (XRD) and Raman spectroscopy. The techniques used allowed to show a good interaction between graphite and TPS and confirmed the predicted conductive properties, showing the potential of application as a substrate, in the development of electrochemical sensors. Electrochemical characterization by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) was also carried out, which allowed defining the best proportion of graphite:TPS as the composite of 60:40 w/w. The technique of differential pulse voltammetry (DPV) was used to determine the catechol molecule over a range of 0.1 to 2.0 mmol L-1, showing a linear regression (R2) of 0.9996 and limit of detection (LOD) and limit of quantitation (LOQ) values equal to 1.85×10-6 mol L-1 and 6.18×10-7 mol L-1, respectively. The results showed good precision, selectivity, and stability, proving the application as an electrochemical sensor to detect catechol (CC) in contaminated water.

Acute myocardial infarction (AMI) is the main cause of death worldwide, and the time of diagnosis is decisive for the effectiveness of the treatment of patients with AMI. Creatine kinase-myocardial band (CK-MB) has a predominance and high affinity with myocardial tissue, making it considered one of the main biomarkers for the diagnosis of AMI. In this work, we report a novel biodegradable composite material based on a polymer blend of Poly­(3-hydroxybutyrate-co-3-hydroxyvalerate) and Poly­(butylene adipate-co-terephthalate) (PHBV:Ecoflex) and graphite microparticles for sensitive and selective electrochemical detection of CK-MB. The morphological and physicochemical characterizations of the thermoplastic composite material revealed a homogeneous and synergistic distribution of the graphite microparticles through the blend structure, providing low defects and high electrical conductivity with high electron transfer kinetics (k 0 = 3.54 × 10–3 cm s–1) features with adequate flexibility for point-of-care applications. The portable and disposable devices were applied to detect CK-MB using the electrochemical impedance spectroscopy (EIS) technique in a relevant clinical concentration ranging from 5.0 ng mL–1 to 100.0 ng mL–1 and presented a limit of detection of 0.26 ng mL–1 CK-MB. The selectivity of the sensor was confirmed by testing the potential interference of major biomolecules found in biofluids and other relevant macromolecules. The accuracy and robustness were assessed by addition and recovery protocol in urine and saliva samples without sample pretreatment and demonstrated the potential of our method for rapid and decentralized tests of AMI. In addition, the study of the thermal, biological, and photodegradation of the devices after being used was also carried out, aiming at the disposal of the material more sustainably.