Franklindgaard3865
Cell-laden printing is the most commonly used approach in 3D bioprinting. One of the major drawbacks of cell-laden printing is that cell viability is highly affected by the extrusion pressure and shear force in the printing process. We present a new cell-deposition method by using the superabsorbent capability of 3D printed scaffolds with four ink formations 2010 nanocrystal/alginate (NCA 20/10), 2010 nanofiber/alginate (NFA 20/10), 2002 nanocrystal/alginate (NCA 20/02) and 2002 nanofiber/alginate (NFA 20/02). Limited pores were observed from the surface of inherent NCA and NFA scaffolds, which may limit the numbers of cells to enter into the scaffolds. Therefore, we designed a dual-porous (DP) structure to connect the inherent pores (IPs) to the scaffold surface. Due to these porous structures, NCA and NFA scaffolds exhibit an excellent capability to absorb cell suspension, which may be used for depositing cells to 3D-printed scaffolds, namely self-absorbent (SA) deposition. Compared to the conventional top-loading (TL) method, the SA method had more uniform cell distributions in the entire 3D-printed scaffolds and higher efficiency of cell deposition. For the TL method, DP scaffold exhibited a more uniform cell distribution, which may provide a better microenvironment for the cells in comparison to the IP scaffold. For both cell loading methods, a rapid increase of cell number was observed in the first 4 days of culture in the 3D-printed NCA and NFA structures. NFA 20/02 exhibits the best cell viability compared to the other three inks. In conclusion, the SA method may serve as a new approach for loading cells in cell-free 3D-bioprinting, and DP design could improve the efficiency of the cell deposition.Bioimpedance measurements are currently used to monitor various biological processes and are potentially useful for studies of urodynamics. Global impedance (GI) and focused impedance measurements (FIM) can be used to monitor bladder volumes, but these are subject to varying conductivity of urine. To address this, we emulated a human bladder using an agar phantom filled with saline solutions of varying conductivities and estimated volumes using a modified FIM-based approach. Using this novel strategy, electrical potentials did not change significantly with constant liquid volumes, even when the conductivity of the saline solutions was varied between 1.027 to 1.877 and 2.610 S/m. Conversely, GI and classic FIM measurements of constant liquid volumes varied with conductivity. These observations suggest that the proposed FIM approach is suitable for bladder volume estimation due to its robustness against uncertainties of conductivity. The bioimpedance hardware used in our experiments comprised 8 electrodes and a a small and low cost impedance measurement system based on an AFE4300 direct impedance measurement device.
3D printed patient-specific coronary models have the ability to enable repeatable benchtop experiments under controlled blood flow conditions. This approach can be applied to CT-derived patient geometries to emulate coronary flow and related parameters such as Fractional Flow Reserve (FFR).
This study uses 3D printing to compare such benchtop FFR results with a non-invasive CT-FFR research software algorithm and catheter based invasive FFR (I-FFR) measurements. Fifty-two patients with a clinical indication for I-FFR underwent a research Coronary CT Angiography (CCTA) prior to catheterization. CT images were used to measure CT-FFR and to generate patient-specific 3D printed models of the aortic root and three main coronary arteries. Each patient-specific model was connected to a programmable pulsatile pump and benchtop FFR (B-FFR) was derived from pressures measured proximal and distal to coronary stenosis using pressure transducers. B-FFR was measured for two coronary outflow rates ('normal', 250 ml min
; and 'hyperemic', 500 ml min
) by adjusting the model's distal coronary resistance.
Pearson correlations and ROC AUC were calculated using invasive I-FFR as reference. The Pearson correlation factor of CT-FFR and B-FFR-500 was 0.75 and 0.71, respectively. Areas under the ROCs for CT-FFR and B-FFR-500 were 0.80 (95%CI 0.70-0.87) and 0.81 (95%CI 0.64-0.91) respectively.
Benchtop flow simulations with 3D printed models provide the capability to measure pressure changes at any location in the model, for ultimately emulating the FFR at several simulated physiological blood flow conditions.
https//clinicaltrials.gov/show/NCT03149042.
https//clinicaltrials.gov/show/NCT03149042.More often the embolic materials in the brain create artefacts in the planning CT images that could lead to a dose variation in planned and delivered dose. The aim of the study was to evaluate the dosimetric effect of artefacts generated by the Onyx™ embolization material during Stereotactic Radiosurgery/Radiotherapy (SRS/SRT) planning. Selleckchem mTOR inhibitor An in-house made novel Polymethyl Methacrylate (PMMA) head phantom (specially designed for SRS/SRT plans) was used for this purpose. For the evaluation process, we have created concentric ring structures around the central Onyx materials on both the CT sets (with and without Onyx material). The verification plans were generated using different algorithms namely Analytical Anisotropic Algorithm (AAA), Acuros XB and Monaco based Monte Carlo on both CT sets. Mean integral dose over the region of interest were calculated in both CT sets. The dosimetric results shows, due to the presence of Onyx material, relative variation in mean integral dose to the proximal structure (Ring 1) were -4.02%, -2.98%, and -2.49% for Monte Carlo, Acuros XB, and AAA respectively. Observed variations are attributed to the presence of artefacts due to Onyx material. Artefacts influence the accuracy of dose calculation during the planning. All the calculation algorithms are not equally capable to account such variations. Special cares are to be taken while choosing the calculation algorithms as it impacts the results of treatment outcome.Gliomas are the most common intracranial tumors, featured by a high mortality rate. They represent about 28% of all primary central nervous system (CNS) tumors and 80% of all malignant brain tumors. Cytotoxic chemotherapy is one of the conventional treatments used for the treatment, but it often shows rather limited efficacy and severe side effects on healthy organs, due to the low selectivity of the therapy for malignant cells and to a limited access of the drug to the tumor site, caused by the presence of the Blood-Brain Barrier. In order to resolve these limitations, recently an Erythro-Magneto-HA-Virosome (EMHV) drug delivery system (DDS), remotely controllable through an externally applied magnetic field, has been proposed. To accurately localize the EMHV at the target area, a system able to generate an adequate magnetic field is necessary. In this framework, the objective of this paper was to design and develop a magnetic helmet for the localization of the proposed EMHV DDS in the brain area. The results demonstrated, through the implementation of therapeutic efficacy maps, that the magnetic helmet designed in the study is a potential promising magnetic generation system useful for studying the possible usability of the magnetic helmet in the treatment of glioma and possibly other CNS pathologies by EMHV DDS.
