Function of mesenchymal stem cells following loading of gold nanotracers

BACKGROUND: Stem cells can differentiate into multiple cell types, and therefore can be used for cellular therapies, including tissue repair. However, the participation of stem cells in tissue repair and neovascularization is not well understood. Therefore, implementing a noninvasive, long-term imaging technique to track stem cells in vivo is needed to obtain a better understanding of the wound healing response. Generally, we are interested in developing an imaging approach to track mesenchymal stem cells (MSCs) in vivo after delivery via a polyethylene glycol modified fibrin matrix (PEGylated fibrin matrix) using MSCs loaded with gold nanoparticles as nanotracers. The objective of the current study was to assess the effects of loading MSCs with gold nanoparticles on cellular function. METHODS: In this study, we utilized various gold nanoparticle formulations by varying size and surface coatings and assessed the efficiency of cell labeling using darkfield microscopy. We hypothesized that loading cells with gold nanotracers would not significantly alter cell function due to the inert and biocompatible characteristics of gold. The effect of nanoparticle loading on cell viability and cytotoxicity was analyzed using a LIVE/DEAD stain and an MTT assay. The ability of MSCs to differentiate into adipocytes and osteocytes after nanoparticle loading was also examined. In addition, nanoparticle loading and retention over time was assessed using inductively coupled plasma mass spectrometry (ICP-MS). CONCLUSION: Our results demonstrate that loading MSCs with gold nanotracers does not alter cell function and, based on the ICP-MS results, long-term imaging and tracking of MSCs is feasible. These findings strengthen the possibility of imaging MSCs in vivo, such as with optical or photoacoustic imaging, to understand better the participation and role of MSCs in neovascularization

Evaluation of gold nanotracers to track adipose-derived stem cells in a PEGylated fibrin gel for dermal tissue engineering applications

Evaluating the regenerative capacity of a tissue-engineered device in a noninvasive and synchronous manner is critical to determining the mechanisms for success in clinical applications. In particular, directly tracking implanted cells in a three-dimensional (3D) scaffold is desirable in that it enables the monitoring of cellular activity in a specific and localized manner. The authors’ group has previously demonstrated that the PEGylation of fibrin results in a 3D scaffold that supports morphologic and phenotypic changes in mesenchymal stem cells that may be advantageous in wound healing applications. Recently, the authors have evaluated adipose-derived stem cells (ASCs) as a mesenchymal cell source to regenerate skin and blood vessels due to their potential for proliferation, differentiation, and production of growth factors. However, tracking and monitoring ASCs in a 3D scaffold, such as a PEGylated fibrin gel, have not yet been fully investigated. In the current paper, nanoscale gold spheres (20 nm) as cell tracers for ASCs cultured in a PEGylated fibrin gel were evaluated. An advanced dual-imaging modality combining ultrasound and photoacoustic imaging was utilized to monitor rat ASCs over time. The ASCs took up gold nanotracers and could be detected up to day 16 with high sensitivity using photoacoustic imaging. There were no detrimental effects on ASC morphology, network formation, proliferation, and protein expression/secretion (ie, smooth muscle α-actin, vascular endothelial growth factor, matrix metalloproteinase-2, and matrix metalloproteinase-9) associated with gold nanotracers. Therefore, utilization of gold nanotracers can be an effective strategy to monitor the regenerative process of a stem cell source in a 3D gel for vascular and dermal tissue engineering applications

Civilinė teisė. Bendroji dalis : Vadovėlis. T. 1

Bibliogr. išnašoseVadovėlyje supažindinama su Lietuvos Respublikos civilinės teisės pamatiniais postulatais: civilinės teisės principais, jos teisinio reglamentavimo metodo ypatumais, šaltiniais ir civilinių santykių dalyviais - fiziniais ir juridiniais asmenimis, civilinės teisės paskirtimi ir jos taikymo sritimis. Taip pat pateikiama trumpa Lietuvos civilinės teisės istorinės raidos apžvalga, bei jos santykis su kitomis pasaulyje egzistuojančiomis privatinėmis teisės sistemomis. Šio vadovėlio tikslas - išmokyti pradedančiuosius studijas suvokti civilinės teisės esmę; analizuoti ir vertinti civilinės teisės reglamentuojamus visuomeninius santykius, atskirti juos nuo kitų teisinių santykių. Šios žinios ir gebėjimai yra būtina prielaida studijuoti kitas civilines teisės kurso temas- sandorius, terminus, atstovavimą, daiktinę teisę, prievoles. Vadovėlis skirtas aukštosiose mokyklose studijuojantiems teisę, taip pat jis gali praversti ir kitų universitetinių studijų programų, pvz., vadybos, viešojo administravimo, finansų, studentamsMykolo Romerio universiteta

Aero-optical Distortions Of Turbulent Boundary Layers: Hypersonic Dns

Four Direct Numerical Simulation (DNS) datasets covering effective freestream Mach numbers of 8 through 14 are used to investigate the behavior of turbulence-induced aero-optical distortions in hypersonic boundary layers. The datasets include two from simulations of flat plate boundary layers (Mach 8 and 14) and two from simulations of flow over a sharp cone (Mach 8 and 14). Instantaneous three-dimensional fields of density from each DNS are converted to refraction index and integrated to produce distributions of the Optical Path Differences (OPD) caused by turbulence. These values are then compared to experimental data from the literature and to an existing model for the root-mean-square of the OPD. Although the model was originally developed for flows with Mach ≤ 5, it provides a basis to which we compare the hypersonic data