3D Printing and Nanotechnology: A Multiscale Alliance in Personalized Medicine

3D printing and nanotechnology have been two important tools in the development of therapeutic approaches for personalized medicine. More recently, their alliance has been improved in an effort to build innovative, versatile, multifunctional, and/or smart medical and pharmaceutical products. Therefore, an extensive review about scientific studies that ally 3D printing and nanomaterials in the development of new approaches for pharmaceutical and medical applications for the treatment and prevention of diseases is presented here. The articles are classified into five categories according to their main application: Cell growth and tissue engineering, antimicrobial, drug delivery, stimulus-response, and theranostics. Semisolid extrusion, inorganic nanoparticles, and cell growth and tissue engineering are the most reported 3D printing technique, type of nanomaterial, and application, respectively. The increase in papers dedicated to these areas is also notable, especially in the 2019 and 2020, when semisolid extrusion became the most used technique, overcoming fused deposition modelling. In fact, this review highlights that the possibility of an alliance between 3D printing and nanotechnology for the production of multiscale materials is undoubtedly a great opportunity for knowledge and innovation in the pharmaceutical and medical area.     

A novel polymer‐based genosensor for the detection and quantification of Streptococcus pneumoniae in genomic DNA sample

The Streptococcus pneumoniae detection plays an important role in the diagnosis and monitoring of pneumococcal diseases. A genosensor based on graphite electrodes modified with polymer was developed for such detection. First, the poly(4‐aminophenol) film was electrochemically deposited on a graphite electrode. Afterward, an S. pneumoniae‐specific oligonucleotide (Strep1), isolated from conserved regions of the bacterial genome, was immobilized onto the modified electrode surface and used for the test with complementary target oligonucleotide (Strep2) or genomic DNA. The genosensor was evaluated using electrochemical techniques and atomic force microscopy. Poly(4‐aminophenol) film caused an increase in probe immobilization, monitoring the guanine oxidation peak. The detection limits obtained using differential pulse voltammetry and electrochemical spectroscopy impedance were 54 and 28 ng mL^?1, respectively. The novel genosensor was efficient for the immobilization and detection of S. pneumoniae genomic DNA. POLYM. ENG. SCI., 58:1308–1314, 2018. © 2017 Society of Plastics Engineers     

Removal of As(V) and Cr(VI) from aqueous solutions using solid waste from leather industry

This study evaluated the feasibility of using a solid waste from the leather industry as an adsorbent for removal of Cr(VI) and As(V) from aqueous media. The adsorbent material was characterized by chemical analyses, infrared spectroscopy, and scanning electronic microscopy (SEM) prior to reaction in order to assess its surface properties. Langmuir and Freundlich equations were used for analyzing the experimental data, which showed a better fit to the Langmuir model, thus suggesting a monolayer adsorption process in the surface of the adsorbent. The high amounts of Cr(VI)-133 mg g(-1) and As(V)-26 mg g(-1) adsorbed demonstrates the great potential for using this solid waste from the leather industry as a low-cost alternative to the traditionally used adsorbent materials.     

Dry Reforming of Methane over Mg-Co-Al Mixed-Oxides Catalysts: Effect of Mg Content and Reduction Conditions

Mg-Co-Al mixed oxides were synthesized by the precipitation method and evaluated for dry reforming of methane. The samples were characterized by thermal techniques (TGA/DTA, NH₃-TPD, H₂-TPR, and TPO), specific surface area, and X-ray diffraction (XRD). Activity runs were conducted at atmospheric pressure, temperatures between 400 and 550°C, a CH₄/CO₂ molar ratio of 1, and a space velocity of 6000 NmL CH₄/g/h. The partial substitution of Co with Mg increased the surface area and thermal stability and changed the reducibility and acid-base properties of the samples. These modifications led to a higher activity for dry reforming of methane for the catalyst with Mg/Co = 0.5, primarily due to its enhanced thermal stability. However, its higher activity was followed by higher amounts of coke. The different activation procedures highlighted Co₃O₄ as the main active phase rather than the Co-mixed oxides. Therefore, milder activation temperatures are required to properly reduce the Co₃O₄ phase and avoid sintering.     

Primary Cilia Structure Is Prolonged in Enteric Neurons of 5xFAD Alzheimer’s Disease Model Mice

Neurodegenerative diseases such as Alzheimer’s disease (AD) have long been acknowledged as mere disorders of the central nervous system (CNS). However, in recent years the gut with its autonomous nervous system and the multitude of microbial commensals has come into focus. Changes in gut properties have been described in patients and animal disease models such as altered enzyme secretion or architecture of the enteric nervous system. The underlying cellular mechanisms have so far only been poorly investigated. An important organelle for integrating potentially toxic signals such as the AD characteristic A-beta peptide is the primary cilium. This microtubule-based signaling organelle regulates numerous cellular processes. Even though the role of primary cilia in a variety of developmental and disease processes has recently been recognized, the contribution of defective ciliary signaling to neurodegenerative diseases such as AD, however, has not been investigated in detail so far. The AD mouse model 5xFAD was used to analyze possible changes in gut functionality by organ bath measurement of peristalsis movement. Subsequently, we cultured primary enteric neurons from mutant mice and wild type littermate controls and assessed for cellular pathomechanisms. Neurite mass was quantified within transwell culturing experiments. Using a combination of different markers for the primary cilium, cilia number and length were determined using fluorescence microscopy. 5xFAD mice showed altered gut anatomy, motility, and neurite mass of enteric neurons. Moreover, primary cilia could be demonstrated on the surface of enteric neurons and exhibited an elongated phenotype in 5xFAD mice. In parallel, we observed reduced β-Catenin expression, a key signaling molecule that regulates Wnt signaling, which is regulated in part via ciliary associated mechanisms. Both results could be recapitulated via in vitro treatments of enteric neurons from wild type mice with A-beta. So far, only a few reports on the probable role of primary cilia in AD can be found. Here, we reveal for the first time an architectural altered phenotype of primary cilia in the enteric nervous system of AD model mice, elicited potentially by neurotoxic A-beta. Potential changes on the sub-organelle level—also in CNS-derived neurons—require further investigations.     

A novel,efficient procedure for acylation of cellulose under homogeneous solution conditions

Commercially available cellulose (Avicel PH101) was successfully acylated under homogeneous solution conditions by the following novel procedure: 2.0 g of cellulose and 5.0 g of LiCl were introduced into a glass reactor, magnetic stirring was started, the pressure was reduced to 2 mmHg, the temperature was raised to 110°C in 30 min, and the reactor was kept under these conditions for another 30 min. N,N‐Dimethylacetamide, 60 mL, was introduced, atmospheric pressure was restored, and the temperature was raised to 150°C in 30 min. The system was kept under these conditions for 1 h, then the temperature was decreased to 40°C; in 2 h a clear cellulose solution was obtained. Acid anhydride was added, and the solution was stirred at 60°C for additional 18 h. Acetates, propionates, butyrates, and acetate/butyrate mixed ester were prepared with excellent reproducibility of the degree of substitution, from 1 to 3. The degree of polymerization of cellulose is negligibly affected by these reaction conditions. The distribution of the acetyl moiety among the three OH groups of the anhydroglucose unit follows the order C₆ > C₂ > C₃. Features relevant to the industrial application of this novel procedure are discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1355–1360, 1999     

Production and Corrosion Resistance of Thermally Sprayed Fe-Based Amorphous Coatings from Mechanically Milled Feedstock Powders

Mechanically milled FeCrNbB feedstock powders from commercial precursors were used to produce amorphous coatings through two different industrial thermal-spraying techniques: high-velocity oxygen fuel (HVOF) and flame spraying. Microstructure, thermal behavior, and hardness of the coatings and their corrosion resistances in acidic and alkaline chloride-rich media were comparatively studied. HVOF process was effective to produce ~ 200-µm-thick highly amorphous coatings with hardness over than 700 HV_0.3 and low porosity (~ 5 pct). Flame-sprayed ~ 220-µm-thick coatings were nanocrystalline, composed of α-Fe, Fe₂B, FeNbB, and Fe₂O₃ phases and presented hardness of 564 HV_0.3 and ~ 10 pct porosity. Electrochemical measurements indicated that HVOF coatings exhibit higher corrosion resistance than flame-sprayed ones thanks to the higher amorphous content and lower porosity resulting from the former processing route. Electrochemical impedance spectroscopy results demonstrated that amorphous HVOF Fe₆₀Cr₈Nb₈B₂₄ (at. pct) coatings are interesting to protect mild steels such as the API 5L X80 against corrosion in chloride-rich environments.