Matching Items (4)
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- All Subjects: Photoacoustic Imaging
- All Subjects: Tissue Engineering
- Creators: Smith, Barbara
Description
Cardiac tissue engineering is an emerging field that has the potential to regenerate and repair damaged cardiac tissues after myocardial infarction. Numerous studies have introduced hydrogel-based cardiac tissue constructs featuring suitable microenvironments for cell growth along with precise surface topographies for directed cell organization. Despite significant progress, previously developed cardiac tissue constructs have suffered from electrically insulated matrices and low cell retention. To address these drawbacks, we fabricated micropatterned hybrid hydrogel constructs (uniaxial microgrooves with 50 µm with) using a photocrosslinkable gelatin methacrylate (GelMA) hydrogel incorporated with gold nanorods (GNRs). The electrical impedance results revealed a lower impedance in the GelMA-GNR constructs versus the pure GelMA constructs. Superior electrical conductivity of GelMA-GNR hydrogels (due to incorporation of GNRs) enabled the hybrid tissue constructs to be externally stimulated using a pulse generator. Furthermore, GelMA-GNR tissue hydrogels were tested to investigate the biological characteristics of cultured cardiomyocytes. The F-actin fiber analysis results (area coverage and alignment indices) revealed higher directed (uniaxial) cytoskeleton organization of cardiac cells cultured on the GelMA-GNR hydrogel constructs in comparison to pure GelMA. Considerable increase in the coverage area of cardiac-specific markers (sarcomeric α-actinin and connexin 43) were observed on the GelMA-GNR hybrid constructs compared to pure GelMA hydrogels. Despite substantial dissimilarities in cell organization, both pure GelMA and hybrid GelMA-GNR hydrogel constructs provided a suitable microenvironment for synchronous beating of cardiomyocytes.
ContributorsMoore, Nathan Allen (Author) / Nikkhah, Mehdi (Thesis director) / Smith, Barbara (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Breast cancer cell invasion is a highly orchestrated process driven by a myriad of complex microenvironmental stimuli. These complexities make it difficult to isolate and assess the effects of specific parameters including matrix stiffness and tumor architecture on disease progression. In this regard, morphologically accurate tumor models are becoming instrumental to perform fundamental studies on cancer cell invasion within well-controlled conditions. In this study, the use of photocrosslinkable hydrogels and a novel, two-step photolithography technique was explored to microengineer a 3D breast tumor model. The microfabrication process presented herein enabled precise localization of the cells and creation of high stiffness constructs adjacent to a low stiffness matrix. To validate the model, breast cancer cell lines (MDA-MB-231, MCF7) and normal mammary epithelial cells (MCF10A) were embedded separately within the tumor model and cellular proliferation, migration and cytoskeletal organization were assessed. Proliferation of metastatic MDA-MB-231 cells was significantly higher than tumorigenic MCF7 and normal mammary MCF10A cells. MDA-MB-231 exhibited highly migratory behavior and invaded the surrounding matrix, whereas MCF7 or MCF10A cells formed clusters that were confined within the micropatterned circular features. F-actin staining revealed unique 3D protrusions in MDA-MB-231 cells as they migrated throughout the surrounding matrix. Alternatively, there were abundance of 3D clusters formed by MCF7 and MCF10A cells. The results revealed that gelatin methacrylate (GelMA) hydrogel, integrated with the two-step photolithography technique, has great promise in creating 3D tumor models with well-defined features and tunable stiffness for detailed studies on cancer cell invasion and drug responsiveness.
ContributorsSam, Feba Susan (Author) / Nikkhah, Mehdi (Thesis advisor) / Ros, Robert (Committee member) / Smith, Barbara (Committee member) / Arizona State University (Publisher)
Created2015
Description
Tumor resectioning is a primary method for cancer treatment but is limited by the inability of surgeons to differentiate tissue, which results in the unnecessary removal of healthy tissue. One method that is uniquely suited to circumvent this issue is photoacoustic imaging. However, this technique lacks real time imaging capabilities which are critical for surgical applications. This work explores the development of a real-time optical imaging tool that utilizes optical detection of an acoustic signal. Determining healthy vs unhealthy tissue will enable improved clinical patient outcomes.
ContributorsBurgett, Joshua (Author) / Smith, Barbara (Thesis director) / Takahashi, Timothy (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05
Description
Breast cancer can be imaged at greater depths using photoacoustic imaging to differentiate between cancerous and non-cancerous tissue. Current photoacoustic modalities struggle to display images in real-time because of the required image reconstruction. In this work, we aim to create a real-time photoacoustic imaging system where the photoacoustic effect is detected through changes in index of refraction. To reach this aim, two methods are applied to visualize the acoustic waves including Schlieren optics and differential interference contrast microscopy. This combined approach provides a new tool for the widespread application in clinical settings.
ContributorsSmetanick, Derek (Author) / Burgett, Joshua (Co-author) / Smith, Barbara (Thesis director) / Muthuswamy, Jitendran (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / School of Life Sciences (Contributor)
Created2022-05