A biosensor was developed for directly detecting human immunoglobulin G (IgG) and adenosine triphosphate (ATP) based on stable and reproducible gold nanoparticles/polystyrene-b-poly(2-vinylpyridine) (AuNP/PS-b-P2VP) nanocomposites. The substrates were functionalized with carboxylic acid groups for the covalent binding of anti-IgG and anti-ATP and the detection of IgG and ATP (1 to 150 μg/mL). SEM images of the nanocomposite show 17 ± 2 nm AuNP clusters adsorbed over a continuous porous PS-b-P2VP thin film. UV–VIS and SERS were used to characterize each step of the substrate functionalization and the specific interaction between anti-IgG and the targeted IgG analyte. The UV–VIS results show a redshift of the LSPR band as the AuNP surface was functionalized and SERS measurements showed consistent changes in the spectral features. Principal component analysis (PCA) was used to discriminate between samples before and after the affinity tests. Moreover, the designed biosensor proved to be sensitive to different concentrations of IgG with a limit-of-detection (LOD) down to 1 μg/mL. Moreover, the selectivity to IgG was confirmed using standard solutions of IgM as a control. Finally, ATP direct immunoassay (LOD = 1 μg/mL) has demonstrated that this nanocomposite platform can be used to detect different types of biomolecules after proper functionalization.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by impairment of cognitive functions and memory deterioration, which requires an early diagnosis for effective treatment. The use of immunosensors to detect Alzheimer’s disease biomarkers stand out as a quick and cheap alternative for early detection of the disease. The development of Screen-Printed Electrodes (SPEs) meets a growing demand in the market for applications such as signal transducers in biosensor devices. In this work was development a method for fabrication of low cost SPE for application in the detection of Alzheimer’s disease through autoantibodies. It was produced microelectrodes on polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF) and high-density polyethylene (HDPE) manufactured by DuPont Tyvek® substrates. SPEs produced on Tyvek ^® substrates have shown promising results for low-cost, disposable and flexible sensors. The carbon paste showed excellent adhesion to Tyvek ^® substrate and the electrodes produced showed an electrochemical performance comparable to commercial electrodes, besides reproducible. The detection results showed that it is possible to detect anti-A β 40 autoantibodies in real samples of serum and cerebrospinal fluid using the electrode modified with two bilayers of (PEI/(DDPG + A β 40)) since the capacitance increased more in positive sample with the presence of autoantibody than in negative samples.

To investigate the ultrastructural characteristics and analysis of residual DNA in scaffold models, produced with decellularized vena cava in an experimental model with rabbits. Three groups were created for ultrastructural and residual DNA analysis: group 1 - control, consisting of samples of vena cava in natura; group 2 - SD, consisting of vein fragments submitted to 2% sodium deoxycholate decellularization by shaking (160rpm - Shaker News Brunswick Scientific®) for 1 hour at controlled temperature shaker at 37°C; group 3 - SDS, consisting of vein fragments submitted to 1% sodium dodecyl sulfate decellularization under the same previous condition, for 2 hours. The ultrastructural matrix of the blood vessel maintained its vintegrity after either decellularization models. The results of the two quantification methods demonstrated a significant decrease in the DNA content of the decellularized vena cava samples as compared to the control samples and, differed statistically from each other, p <0.05. The 2% DS protocol for vein decellularization, in this experimental model, was considered the best protocol because it presented less amount of residual DNA without causing substantial destruction of the extracellular matrix.

To evaluate methods that improve adipose-derived stem cells (ASCs) population in decellularized biological venous scaffold for tissue engineering in blood vessels, a model in rabbits. The ASC was expanded until the third passage. Inferior vena cava (IVC) was submitted to the decellularization process using 1% sodium dodecyl sulfate (SDS) or 2% sodium deoxycholate (SD) to compose 12 study groups (G): pure SD or SDS, exposed or not to 1% TritonX-100 (TX-100) and exposed or not to poly-l’lysine and laminin (PL). Scaffolds were covered with 1 × 10⁵ or 1 × 10⁶ ASCs diluted in 10 μL Puramatrix™. The histological analysis was done by cell counting in hematoxylin and eosin (HE) and nuclei count in immunofluorescence (IF) with 4’,6-Diamidine-2’-phenylindole dihydrochloride (DAPI). The study of groups in HE and IF showed similar results. For both analyses,IVC-SD-1 × 10⁶ ASC and IVC-SD-PL-1 × 10⁶ ASC provided the best results. The IF technique showed better sensitivity than HE, with a weak agreement between them. Decellularizing agent and the number of ASC influence scaffolds cellularization response and the best protocols as those ones using SD with or without the addition of PL.

Background: To evaluate tissue regeneration of the urinary bladder after the implantation of a decellularized vein sown with autologous adipose-derived mesenchymal stem cells (ASC) on luminal surfaces. Methods: New Zealand rabbits (n = 10) were distributed in two groups: Group Bioscaffold alone (G1)-decellularized vena cava (1 cm²) was implanted, and Group Bioscaffold plus ACSs (G2)-decellularized vena cava (1 cm²) containing ASCs were implanted. ASCs were expanded, characterized, and maintained for one week in culture with a decellularized vein scaffold. The implants were performed under general anesthesia using a continuous suture pattern. Afterward, 21 d (day) specimens were collected and analyzed by hematoxylin and eosin (HE) histology and scanning electron microscopy (SEM). Results: The integrity of the urinary bladder was maintained in both groups. A superior regenerative process was observed in the G2 group, compared to the G1 group. We observed a greater urothelial epithelialization and maturity of the mucosa and submucosa fibroblasts. Furthermore, SEM demonstrated a notable amount of urothelial villus in the G2 group. Conclusion: Decellularized vena cava scaffolds were able to maintain the integrity of the urinary bladder in the proposed model. In addition, ASCs accelerated the regenerative process development, observed primarily by the new urothelial epithelization and the maturity of mucosa and submucosa fibroblasts.