Effect of the scaffold microenvironment on cell polarizability and capacitance determined by probabilistic computations

DLP printed hDPSC-loaded GelMA microsphere regenerates dental pulp and repairs spinal cord

Dental pulp regeneration is ideal for irreversible pulp or periapical lesions, and in situ stem cell therapy is one of the most effective therapies for pulp regeneration. In this study, we provided an atlas of the non-cultured and monolayer cultured dental pulp cells with single-cell RNA sequencing and analysis. Monolayer cultured dental pulp cells cluster more closely together than non-cultured dental pulp cells, suggesting a lower heterogeneous population with relatively consistent clusters and similar cellular composition. We successfully fabricated hDPSC-loaded microspheres by layer-by-layer photocuring with a digital light processing (DLP) printer. These hDPSC-loaded microspheres have improved stemness and higher multi-directional differentiation potential, including angiogenic, neurogenic, and odontogenic differentiation. The hDPSC-loaded microspheres could promote spinal cord regeneration in rat spinal cord injury models. Moreover, in heterotopic implantation tests on nude mice, CD31, MAP2, and DSPP immunofluorescence signals were observed, implying the formation of vascular, neural, and odontogenetic tissues. In situ experiments in minipigs demonstrated highly vascularized dental pulp and uniformly arranged odontoblast-like cells in root canals of incisors. In short, hDPSC-loaded microspheres can promote full-length dental pulp regeneration at the root canals' coronal, middle, and apical sections, particularly for blood vessels and nerve formation, which is a promising therapeutic strategy for necrotic pulp.

Chlorite oxidized oxyamylose differentially influences the microstructure of fibrin and self assembling peptide hydrogels as well as dental pulp stem cell behavior

Tailored hydrogels mimicking the native extracellular environment could help overcome the high variability in outcomes within regenerative endodontics. This study aimed to evaluate the effect of the chemokine-binding and antimicrobial polymer, chlorite-oxidized oxyamylose (COAM), on the microstructural properties of fibrin and self-assembling peptide (SAP) hydrogels. A further goal was to assess the influence of the microstructural differences between the hydrogels on the in vitro behavior of human dental pulp stem cells (hDPSCs). Structural and mechanical characterization of the hydrogels with and without COAM was performed by atomic force microscopy and scanning electron microscopy to characterize their microstructure (roughness and fiber length, diameter, straightness, and alignment) and by nanoindentation to measure their stiffness (elastic modulus). Then, hDPSCs were encapsulated in hydrogels with and without COAM. Cell viability and circularity were determined using confocal microscopy, and proliferation was determined using DNA quantification. Inclusion of COAM did not alter the microstructure of the fibrin hydrogels at the fiber level while affecting the SAP hydrogel microstructure (homogeneity), leading to fiber aggregation. The stiffness of the SAP hydrogels was sevenfold higher than the fibrin hydrogels. The viability and attachment of hDPSCs were significantly higher in fibrin hydrogels than in SAP hydrogels. The DNA content was significantly affected by the hydrogel type and the presence of COAM. The microstructural stability after COAM inclusion and the favorable hDPSCs' response observed in fibrin hydrogels suggest this system as a promising carrier for COAM and application in endodontic regeneration.

Plant secondary metabolites induced electron flux in microbial fuel cell: investigation from laboratory-to-field scale

Wastewater treatment coupled with electricity recovery in microbial fuel cell (MFC) prefer mixed anaerobic sludge as inoculum in anodic chamber than pure stain of electroactive bacteria (EAB), due to robustness and syntrophic association. Genetic modification is difficult to adopt for mixed sludge microbes for enhancing power production of MFC. Hence, we demonstrated use of eco-friendly plant secondary metabolites (PSM) with sub-lethal concentrations to enhance the rate of extracellular electron transfer between EAB and anode and validated it in both bench-scale as well as pilot-scale MFCs. The PSMs contain tannin, saponin and essential oils, which are having electron shuttling properties and their addition to microbes can cause alteration in cell morphology, electroactive behaviour and shifting in microbial population dynamics depending upon concentrations and types of PSM used. Improvement of 2.1-times and 3.8-times in power densities was observed in two different MFCs inoculated with Eucalyptus-extract pre-treated mixed anaerobic sludge and pure culture of Pseudomonas aeruginosa, respectively, as compared to respective control MFCs operated without adding Eucalyptus-extract to inoculum. When Eucalyptus-extract-dose was spiked to anodic chamber (125 l) of pilot-scale MFC, treating septage, the current production was dramatically improved. Thus, PSM-dosing to inoculum holds exciting promise for increasing electricity production of field-scale MFCs.

Analysis of Different Computational Techniques for Calculating the Polarizability Tensors of Stem Cells with Realistic Three-Dimensional Morphologies

Recently, the National Institute of Standards and Technology has developed a database of three-dimensional (3D) stem cell morphologies grown in ten different scaffolds to study the effect of the cells' environments on their morphologies. The goal of this work is to study the polarizability tensors of these stem cell morphologies, using three independent computational techniques, to quantify the effect of the environment on the electric properties of these cells. We show excellent agreement between the three techniques, validating the accuracy of our calculations. These computational methods allowed us to investigate different meshing resolutions for each stem cell morphology. After validating our results, we use a fast and accurate Pad' approximation formulation to calculate the polarizability tensors of stem cells for any contrast value between their dielectric permittivity and the dielectric permittivity of their environment. We also performed statistical analysis of our computational results to identify which environment generates cells with similar electric properties. The computational analysis and the results reported herein can be used for shedding light on the response of stem cells to electric fields in applications such as dielectrophoresis and electroporation and for calculating the electric properties of similar biological structures with complex 3D shapes.