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Furdella KJ, Witte RS, Vande Geest JP. Tracking delivery of a drug surrogate in the porcine heart using photoacoustic imaging and spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:41016. [PMID: 28192566 DOI: 10.1117/1.jbo.22.4.041016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 01/20/2017] [Indexed: 06/06/2023]
Abstract
Although the drug-eluting stent (DES) has dramatically reduced the rate of coronary restenosis, it still occurs in up to 20% of patients with a DES. Monitoring drug delivery could be one way to decrease restenosis rates. We demonstrate real-time photoacoustic imaging and spectroscopy (PAIS) using a wavelength-tunable visible laser and clinical ultrasound scanner to track cardiac drug delivery. The photoacoustic signal was initially calibrated using porcine myocardial samples soaked with a known concentration of a drug surrogate (DiI). Next, an in situ coronary artery was perfused with DiI for 20 min and imaged to monitor dye transport in the tissue. Finally, a partially DiI-coated stent was inserted into the porcine brachiocephalic trunk for imaging. The photoacoustic signal was proportional to the DiI concentration between 2.4 and 120 ?? ? g / ml , and the dye was detected over 1.5 mm from the targeted coronary vessel. Photoacoustic imaging was also able to differentiate the DiI-coated portion of the stent from the uncoated region. These results suggest that PAIS can track drug delivery to cardiac tissue and detect drugs loaded onto a stent with sub-mm precision. Future work using PAIS may help improve DES design and reduce the probability of restenosis.
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Affiliation(s)
- Kenneth J Furdella
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, Pennsylvania, United States
| | - Russell S Witte
- University of Arizona, Department of Medical Imaging, Tucson, Arizona, United States
| | - Jonathan P Vande Geest
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, Pennsylvania, United States
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Harrison S, Tamimi E, Uhlorn J, Leach T, Vande Geest JP. Computationally Optimizing the Compliance of a Biopolymer Based Tissue Engineered Vascular Graft. J Biomech Eng 2016; 138:2473573. [PMID: 26593773 DOI: 10.1115/1.4032060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 11/08/2022]
Abstract
Coronary heart disease is a leading cause of death among Americans for which coronary artery bypass graft (CABG) surgery is a standard surgical treatment. The success of CABG surgery is impaired by a compliance mismatch between vascular grafts and native vessels. Tissue engineered vascular grafts (TEVGs) have the potential to be compliance matched and thereby reduce the risk of graft failure. Glutaraldehyde (GLUT) vapor-crosslinked gelatin/fibrinogen constructs were fabricated and mechanically tested in a previous study by our research group at 2, 8, and 24 hrs of GLUT vapor exposure. The current study details a computational method that was developed to predict the material properties of our constructs for crosslinking times between 2 and 24 hrs by interpolating the 2, 8, and 24 hrs crosslinking time data. matlab and abaqus were used to determine the optimal combination of fabrication parameters to produce a compliance matched construct. The validity of the method was tested by creating a 16-hr crosslinked construct of 130 μm thickness and comparing its compliance to that predicted by the optimization algorithm. The predicted compliance of the 16-hr construct was 0.00059 mm Hg-1 while the experimentally determined compliance was 0.00065 mm Hg-1, a relative difference of 9.2%. Prior data in our laboratory has shown the compliance of the left anterior descending porcine coronary (LADC) artery to be 0.00071 ± 0.0003 mm Hg-1. Our optimization algorithm predicts that a 258-μm-thick construct that is GLUT vapor crosslinked for 8.1 hrs would match LADC compliance. This result is consistent with our previous work demonstrating that an 8-hr GLUT vapor crosslinked construct produces a compliance that is not significantly different from a porcine coronary LADC.
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von Haartman E, Lindberg D, Prabhakar N, Rosenholm JM. On the intracellular release mechanism of hydrophobic cargo and its relation to the biodegradation behavior of mesoporous silica nanocarriers. Eur J Pharm Sci 2016; 95:17-27. [PMID: 27267567 DOI: 10.1016/j.ejps.2016.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/30/2016] [Accepted: 06/01/2016] [Indexed: 11/25/2022]
Abstract
The intracellular release mechanism of hydrophobic molecules from surface-functionalized mesoporous silica nanoparticles was studied in relation to the biodegradation behavior of the nanocarrier, with the purpose of determining the dominant release mechanism for the studied drug delivery system. To be able to follow the real-time intracellular release, a hydrophobic fluorescent dye was used as model drug molecule. The in vitro release of the dye was investigated under varying conditions in terms of pH, polarity, protein and lipid content, presence of hydrophobic structures and ultimately, in live cancer cells. Results of investigating the drug delivery system show that the degradation and drug release mechanisms display a clear interdependency in simple aqueous solvents. In pure aqueous media, the cargo release was primarily dependent on the degradation of the nanocarrier, while in complex media, mimicking intracellular conditions, the physicochemical properties of the cargo molecule itself and its interaction with the carrier and/or surrounding media were found to be the main release-governing factors. Since the material degradation was retarded upon loading with hydrophobic guest molecules, the cargo could be efficiently delivered into live cancer cells and released intracellularly without pronounced premature release under extracellular conditions. From a rational design point of view, pinpointing the interdependency between these two processes can be of paramount importance considering future applications and fundamental understanding of the drug delivery system.
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Affiliation(s)
- Eva von Haartman
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, BioCity, Tykistökatu 6A, FI 20520 Turku, Finland
| | - Desiré Lindberg
- Center for Functional Materials, Laboratory of Physical Chemistry, Faculty of Science and Engineering, Åbo Akademi University, Porthaninkatu 3-5, FI 20500 Turku, Finland
| | - Neeraj Prabhakar
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, BioCity, Tykistökatu 6A, FI 20520 Turku, Finland; Laboratory of Biophysics, University of Turku, Tykistökatu 6A, FI 20520 Turku, Finland
| | - Jessica M Rosenholm
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, BioCity, Tykistökatu 6A, FI 20520 Turku, Finland.
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Armstrong MH, Buganza Tepole A, Kuhl E, Simon BR, Vande Geest JP. A Finite Element Model for Mixed Porohyperelasticity with Transport, Swelling, and Growth. PLoS One 2016; 11:e0152806. [PMID: 27078495 PMCID: PMC4831841 DOI: 10.1371/journal.pone.0152806] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 03/18/2016] [Indexed: 01/07/2023] Open
Abstract
The purpose of this manuscript is to establish a unified theory of porohyperelasticity with transport and growth and to demonstrate the capability of this theory using a finite element model developed in MATLAB. We combine the theories of volumetric growth and mixed porohyperelasticity with transport and swelling (MPHETS) to derive a new method that models growth of biological soft tissues. The conservation equations and constitutive equations are developed for both solid-only growth and solid/fluid growth. An axisymmetric finite element framework is introduced for the new theory of growing MPHETS (GMPHETS). To illustrate the capabilities of this model, several example finite element test problems are considered using model geometry and material parameters based on experimental data from a porcine coronary artery. Multiple growth laws are considered, including time-driven, concentration-driven, and stress-driven growth. Time-driven growth is compared against an exact analytical solution to validate the model. For concentration-dependent growth, changing the diffusivity (representing a change in drug) fundamentally changes growth behavior. We further demonstrate that for stress-dependent, solid-only growth of an artery, growth of an MPHETS model results in a more uniform hoop stress than growth in a hyperelastic model for the same amount of growth time using the same growth law. This may have implications in the context of developing residual stresses in soft tissues under intraluminal pressure. To our knowledge, this manuscript provides the first full description of an MPHETS model with growth. The developed computational framework can be used in concert with novel in-vitro and in-vivo experimental approaches to identify the governing growth laws for various soft tissues.
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Affiliation(s)
- Michelle Hine Armstrong
- Graduate Interdisciplinary Program in Applied Mathematics, The University of Arizona, Tucson, AZ, United States of America
| | - Adrián Buganza Tepole
- Department of Mechanical Engineering, Stanford University, Stanford, CA, United States of America
| | - Ellen Kuhl
- Department of Mechanical Engineering, Stanford University, Stanford, CA, United States of America
| | - Bruce R Simon
- Department of Aerospace and Mechanical Engineering, The University of Arizona, Tucson, AZ, United States of America
| | - Jonathan P Vande Geest
- Graduate Interdisciplinary Program in Applied Mathematics, The University of Arizona, Tucson, AZ, United States of America.,Department of Aerospace and Mechanical Engineering, The University of Arizona, Tucson, AZ, United States of America.,Graduate Interdisciplinary Program of Biomedical Engineering, The University of Arizona, Tucson, AZ, United States of America.,BIO5 Institute for Biocollaborative Research, The University of Arizona, Tucson, AZ 85721, United States of America.,Department of Biomedical Engineering, The University of Arizona, Tucson, AZ 85721, United States of America.,Department of Bioengineering, The University of Pittsburgh, Pittsburgh, PA 15219, United States of America
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Thomas G, van Voskuilen J, Truong H, Song JY, Gerritsen HC, Sterenborg HJCM. In vivo nonlinear spectral imaging as a tool to monitor early spectroscopic and metabolic changes in a murine cutaneous squamous cell carcinoma model. BIOMEDICAL OPTICS EXPRESS 2014; 5:4281-99. [PMID: 25574438 PMCID: PMC4285605 DOI: 10.1364/boe.5.004281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/06/2014] [Accepted: 11/07/2014] [Indexed: 05/11/2023]
Abstract
Timely detection of cutaneous squamous cell carcinoma with non-invasive modalities like nonlinear spectral imaging (NLSI) can ensure efficient preventive or therapeutic measures for patients. In this study, in vivo NLSI was used to study spectral characteristics in murine skin treated with 7, 12-dimethylbenz(a)anthracene. The results show that NLSI could detect emission spectral changes during the early preclinical stages of skin carcinogenesis. Analyzing these emission spectra using simulated band-pass filters at 450-460 nm and 525-535 nm, gave parameters that were expressed as a ratio. This ratio was increased and thus suggestive of elevated metabolic activity in early stages of skin carcinogenesis.
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Affiliation(s)
- Giju Thomas
- Department of Biomedical Engineering and Physics, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The
Netherlands
- Centre for Optical Diagnostics and Therapy, Erasmus Medical Centre, Post Box 2040, 3000 CA, Rotterdam, The
Netherlands
| | - Johan van Voskuilen
- Department of Molecular Biophysics, Utrecht University, 3508 TA, Utrecht, The
Netherlands
| | - Hoa Truong
- Department of Molecular Biophysics, Utrecht University, 3508 TA, Utrecht, The
Netherlands
| | - Ji-Ying Song
- Department of Experimental Animal Pathology, the Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, Amsterdam, The
Netherlands
| | - Hans C. Gerritsen
- Department of Molecular Biophysics, Utrecht University, 3508 TA, Utrecht, The
Netherlands
| | - H. J. C. M. Sterenborg
- Department of Biomedical Engineering and Physics, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The
Netherlands
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Meyer T, Schmitt M, Dietzek B, Popp J. Accumulating advantages, reducing limitations: multimodal nonlinear imaging in biomedical sciences - the synergy of multiple contrast mechanisms. JOURNAL OF BIOPHOTONICS 2013; 6:887-904. [PMID: 24259267 DOI: 10.1002/jbio.201300176] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 11/06/2013] [Indexed: 05/29/2023]
Abstract
Multimodal nonlinear microscopy has matured during the past decades to one of the key imaging modalities in life science and biomedicine due to its unique capabilities of label-free visualization of tissue structure and chemical composition, high depth penetration, intrinsic 3D sectioning, diffraction limited resolution and low phototoxicity. This review briefly summarizes first recent advances in the field regarding the methodology, e.g., contrast mechanisms and signal characteristics used for contrast generation as well as novel image processing approaches. The second part deals with technologic developments emphasizing improvements in penetration depth, imaging speed, spatial resolution and nonlinear labeling strategies. The third part focuses on recent applications in life science fundamental research and biomedical diagnostics as well as future clinical applications.
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Affiliation(s)
- Tobias Meyer
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller-University Jena, Helmholtzweg 4, 07743 Jena, Germany
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Keyes JT, Simon BR, Vande Geest JP. A finite element study on variations in mass transport in stented porcine coronary arteries based on location in the coronary arterial tree. J Biomech Eng 2013; 135:61008-11. [PMID: 23699720 DOI: 10.1115/1.4024137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/04/2013] [Indexed: 11/08/2022]
Abstract
Drug-eluting stents have a significant clinical advantage in late-stage restenosis due to the antiproliferative drug release. Understanding how drug transport occurs between coronary arterial locations can better help guide localized drug treatment options. Finite element models with properties from specific porcine coronary artery sections (left anterior descending (LAD), right (RCA); proximal, middle, distal regions) were created for stent deployment and drug delivery simulations. Stress, strain, pore fluid velocity, and drug concentrations were exported at different time points of simulation (0-180 days). Tests indicated that the highest stresses occurred in LAD sections. Higher-than-resting homeostatic levels of stress and strain existed at upwards of 3.0 mm away from the stented region, whereas concentration of species only reached 2.7 mm away from the stented region. Region-specific concentration showed 2.2 times higher concentrations in RCA artery sections at times corresponding to vascular remodeling (peak in the middle segment) compared to all other segments. These results suggest that wall transport can occur differently based on coronary artery location. Awareness of peak growth stimulators and where drug accumulation occurs in the vasculature can better help guide local drug delivery therapies.
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Affiliation(s)
- Joseph T Keyes
- Graduate Interdisciplinary Program in Biomedical Engineering, The University of Arizona,Tucson, AZ 85721, USA.
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