Computational modeling to predict the micromechanical environment in tissue engineering scaffolds

A 50-year systemic review of bioavailability application in Soil environmental criteria and risk assessment

Bioavailability has become a critical factor in improving ecological risk assessment and environmental remediation efficiency in contaminated soil research. However, the soil environmental quality standards and risk assessment procedures used in most countries are still based on the total amount of pollutants for lacking sufficient understanding of the exposure pathways and action mechanisms of pollutants. we collected relevant literature from the Web of Science database, spanning the period from 1950 to 2021 by using Citespace to analyze the scientific development of bioavailability. As of January 09, 2022, the database contained 118,813 publications on bioavailability. The review summarizes the progress in bioavailability research and emerging trends, including exploring advanced analytical techniques, advancing modeling approaches, and integrating interdisciplinary approaches to better understand the fate and behavior of pollutants in complex environmental matrices. In particular, the review emphasizes the need for better integration of bioavailability concepts into soil environmental reference, risk assessment procedures, and environmental remediation strategies. Overall, this review emphasized the necessity of incorporating the concept of bioavailability into soil environmental reference, risk assessment procedures, and environmental remediation strategies.

Roles of irregularity of pore morphology in osteogenesis of Voronoi scaffolds: From the perspectives of MSC adhesion and mechano-regulated osteoblast differentiation

Bone scaffolds designed based on the Voronoi-tessellation algorithm have been increasingly studied owing to their structural similarity with natural cancellous bone. The irregularity of pore morphology (IPM) influences the osteogenesis efficiency of Voronoi scaffolds since it may alter the static and hydromechanical microenvironments for the initial adhesion and mechano-regulated osteoblast differentiation (MrOD) of mesenchymal stem cells (MSCs). In this work, animal experiments were conducted to explore the relationship between IPM and osteogenesis efficiency in Voronoi scaffolds. A computational fluid dynamics (CFD) analysis based on discrete phase models was performed to predict the efficiency of MSC adhesion in different IPMs. Another combined finite element and CFD analysis based on the mechano-regulation algorithm was performed to predict the influence of IPM on the MrOD of the adhesive MSCs. The results showed that the osteogenesis efficiency of the Voronoi scaffolds increased as the IPM rose from low to moderate and then dropped as the IPM further rose. Same trends were also found in the MSC adhesion and MrOD, which caused by the changes of strain tensors on the strut surface and the tortuosity and fluid velocity of the fluid pathway. Moderate IPM induced the highest osteogenesis efficiency owing to its highest efficiencies of MSC adhesion and MrOD. This work identified the optimal IPM for the osteogenesis of Voronoi scaffolds and clarified its biomechanical mechanisms from the adhesion and mechano-regulated differentiation of MSCs, which is of great importance for guiding Voronoi scaffold design when it is used for bone defect repair.

High throughput computational evaluation of how scaffold architecture, material selection, and loading modality influence the cellular micromechanical environment in tissue engineering strategies

BACKGROUND

In tissue engineering (TE) strategies, cell processes are regulated by mechanical stimuli. Although TE scaffolds have been developed to replicate tissue-level mechanical properties, it is intractable to experimentally measure and prescribe the cellular micromechanical environment (CME) generated within these constructs. Accordingly, this study aimed to fill this lack of understanding by modeling the CME in TE scaffolds using the finite element method.

METHODS

A repeating unit of composite fiber scaffold for annulus fibrosus (AF) repair with a fibrin hydrogel matrix was prescribed a series of loading, material, and architectural parameters. The distribution of CME in the scaffold was predicted and compared to proposed target mechanics based on anabolic responses of AF cells.

RESULTS

The multi-axial loading modality predicted the greatest percentage of cell volumes falling within the CME target envelope (%PTE) in the study (65 %PTE for 5.0% equibiaxial tensile strain with 50 kPa radial-direction compression; 7.6 %PTE without radial pressure). Additionally, the architectural scale had a moderate influence on the CME (maximum of 17 %PTE), with minimal change in the tissue-level properties of the scaffold. Scaffold materials and architectures had secondary influences on the predicted regeneration by modifying the tissue-level scaffold mechanics.

CONCLUSIONS

Scaffold loading modality was identified as the critical factor for TE the AF. Scaffold materials and architecture were also predicted to modulate the scaffold loading and, therefore, control the CME indirectly. This study facilitated an improved understanding of the relationship between tissue-level and cell-level mechanics to drive anabolic cell responses for tissue regeneration.