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Three-dimensional (3D) structures are actually the state-of-the-art technique to create porous scaffolds for tissue engineering. Since regeneration in cartilage tissue is limited due to intrinsic cellular properties this study aims to develop and characterize three-dimensional porous scaffolds of poly (L-co-D, L lactide-co-trimethylene carbonate), PLDLA-TMC, obtained by 3D fiber deposition technique. The PLDLA-TMC terpolymer scaffolds (70:30), were obtained and characterized by scanning electron microscopy, gel permeation chromatography, differential scanning calorimetry, thermal gravimetric analysis, compression mechanical testing and study on in vitro degradation, which showed its amorphous characteristics, cylindrical geometry, and interconnected pores. The in vitro degradation study showed significant loss of mechanical properties compatible with a decrease in molar mass, accompanied by changes in morphology. The histocompatibility association of mesenchymal stem cells from rabbit's bone marrow, and PLDLA-TMC scaffolds, were evaluated in the meniscus regeneration, proving the potential of cell culture at in vivo tissue regeneration. Nine New Zealand rabbits underwent total medial meniscectomy, yielding three treatments: implantation of the seeded PLDLA-TMC scaffold, implantation of the unseeded PLDLA-TMC and negative control (defect without any implant). After 24 weeks, the results revealed the presence of fibrocartilage in the animals treated with polymer. However, the regeneration obtained with the seeded PLDLA-TMC scaffolds with mesenchymal stem cells had become intimal to mature fibrocartilaginous tissue of normal meniscus both macroscopically and histologically. This study demonstrated the effectiveness of the PLDLA-TMC scaffold in meniscus regeneration and the potential of mesenchymal stem cells in tissue engineering, without the use of growth factors. It is concluded that bioresorbable polymers represent a promising alternative for tissue regeneration. [ABSTRACT FROM AUTHOR]

Calcium phosphate cement (CPC) that is based on α-tricalcium phosphate (α-TCP) is considered desirable for bone tissue engineering because of its relatively rapid degradation properties. However, such cement is relatively weak, restricting its use to areas of low mechanical stress. Wollastonite fibers (WF) have been used to improve the mechanical strength of biomaterials. However, the biological properties of WF remain poorly understood. Here, we tested the response of osteoblast-like cells to being cultured on CPC reinforced with 5% of WF (CPC-WF). We found that both types of cement studied achieved an ion balance for calcium and phosphate after 3 days of immersion in culture medium and this allowed subsequent long-term cell culture. CPC-WF increased cell viability and stimulated cell differentiation, compared to nonreinforced CPC. We hypothesize that late silicon release by CPC-WF induces increased cell proliferation and differentiation. Based on our findings, we propose that CPC-WF is a promising material for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

The herbicide residue from intensive agricultural activity provokes environmental disturbances and human health injuries. Among the enzymatic disruptor herbicides, mesotrione is able to inhibit 4-hydroxyphenylpyruvate dioxygenase (HPPD), which plays a key role in the carotenoid synthesis. Therefore, enzyme-based sensors are innovative options for monitoring herbicides used in agriculture. Compared to the standard sensors, biosensors have assorted advantages, such as practicality, quick response, low cost, and high sensitivity. A nanobiosensor was developed herein based on HPPD for mesotrione detection. Theoretically, the molecular docking and molecular dynamics simulation estimated the interacting regions of HPPD with mesotrione. Experimentally, the atomic force microscope tip functionalization with HPPD immobilized in self-assembled monolayers was confirmed by fluorescence microscopy and atomic force spectroscopy. The cross-linker N-(3-dimethylaminopropyl)- N_-ethylcarbodiimide hydrochloride was responsible for properly preserving the enzyme on the tip. The nanobiosensor proposed here was successfully able to detect mesotrione molecules. Such effectiveness in the development of nanobiosensors promises reliable, precise, and low-cost techniques, which apply to a broad range of issues, from ecology to medicine. [ABSTRACT FROM AUTHOR]

Objective: Analysis of sperm heads using three different computer morphometrical tools and experimental conditions to find a more reliable and secure strategy among them.Design: Controlled experiments on sperm morphology analysis from volunteers.Setting: Laboratory of microscopy and imaging processing.Patient(s): Ten human semen samples donated by different zoospermic men.Intervention(s): Semen samples were collected by masturbation after > or =72 hours of abstinence.Main Outcome Measure(s): Spermatozoon head morphology was compared by the use of different video-microscopy systems, three computer programs, and various staining conditions and manipulation by different operators. Nonbiological material in the form of latex beads was also used.Result(s): The data obtained suggest that the semiautomatic computer program is the most reliable and secure method for performing sperm analysis, besides the fact that it is a fast process compared with manual methods.Conclusion(s): Computer systems of sperm analysis should incorporate a step of interactive object identification to work properly, allowing the operator to confirm or correct possible computer misidentification. The latex beads were used to confirm the capability of all three computer programs to correctly evaluate nonbiological material. [ABSTRACT FROM AUTHOR]

poly(L‐co‐D,L‐lactic acid) (PLDLA) is a bioresorbable and biocompatible copolymer obtained from the combination of L‐lactic and D, L‐lactic monomers. PLDLA membranes formed by aligned fibers were prepared by AC/DC electrospinning. Solutions of 8 and 10 wt % of PLDLA were used and membranes were collected by a rotating cylindrical collector. The results showed a slight increase in the fiber diameter with the increase in the polymer concentration. Fourier transform infrared spectroscopy results showed no changes in the chemical structure. Dynamic mechanical analysis results showed an increase in the storage modulus and a decrease in glass‐transition temperature for the 10 wt % samples, which was corroborated by differential scanning calorimetry. Thermogravimetric analysis showed a slight variation of the peak degradation temperature. Nevertheless, the samples did not present solvent residues. The membranes were tested in vitro using adipose‐derived mesenchymal stem cells (ASCs). The ASCs proliferated after 1, 7, and 14 days of culture, maintaining a spindle‐like morphology, which evidences their potential for tissue engineering applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47657. [ABSTRACT FROM AUTHOR]

The high increase of agrochemicals application on crops has as consequence a range of environmental disturbances and modifications, due to the biohazard involved on the use of those substances (accumulation and dissemination in bioma). In this context, new detection methods are highlighted as a research subject on environmental monitoring. Therefore, the sensors development combined to nanotechnology is a promising methodology in what concerns effectiveness and selectiveness. This project established specific interaction parameters and methodologies amongst an antibody (anti-atrazine) and the herbicide atrazine, applying atomic force microscopy techniques, which resulted on the development of a specific nanobiosensor to detect herbicides. It was compared substrates functionalized with different substances: atrazine, imazaquim, metsulfuron-methyl and water (control), to evaluate and prove the specific interaction amongst atrazine versus antiatrazine (antigen-antibody complex). Since, as compared with other samples, the interaction observed within this specific complex was detected, the obtained data showed the nanodispositive efficiency. [ABSTRACT FROM AUTHOR]