Engineering Commons^™

Conventional Platinum Metal Implants Provoke Restenosis Responses In Atherogenic But Not Healthy Arteries, Lea M. Morath, Roger J. Guillory Ii, Alexander A. Oliver, Shu Q. Liu, Martin L. Bocks, Galit Katarivas Levy, Jaroslaw Drelich, Jeremy Goldman

Michigan Tech Publications

Platinum-containing stents are commonly used in humans with hypercholesterolemia, whereas preclinical stent evaluation has commonly been performed in healthy animal models, providing inadequate information about stent performance under hypercholesterolemic conditions. In this investigation, we used an ApoE−/− mouse model to test the impact of hypercholesterolemia on neointima formation on platinum-containing implants. We implanted 125 μm diameter platinum wires into the abdominal aortas of ApoE−/− and ApoE+/+ mice for 6 months, followed by histological and immunofluorescence examination of neointimal size and composition. It was found that ApoE−/− mice developed neointimas with four times larger area and ten times greater thickness than …

Biodegradable Magnesium Materials Regulate Ros-Rns Balance In Pro-Inflammatory Macrophage Environment, Maria Paula Kwesiga, Amani A. Gillette, Seyedehfatemeh Razaviamri, Margaret E. Plank, Alexia L. Canull, Zachary Alesch, Weilue He, Bruce Lee, Roger J. Guillory Ii

Michigan Tech Publications

The relationship between reactive oxygen and nitrogen species (ROS-RNS) secretion and the concomitant biocorrosion of degradable magnesium (Mg) materials is poorly understood. We found that Mg foils implanted short term in vivo (24 h) displayed large amounts of proinflammatory F4/80+/iNOS + macrophages at the interface. We sought to investigate the interplay between biodegrading Mg materials (98.6% Mg, AZ31 & AZ61) and macrophages (RAW 264.7) stimulated with lipopolysaccharide (RAW 264.7LPS) to induce ROS-RNS secretion. To test how these proinflammatory ROS-RNS secreting cells interact with Mg corrosion in vitro, Mg and AZ61 discs were suspended approximately 2 mm above a monolayer of …

Mechanical Properties And Morphological Alterations In Fiber-Based Scaffolds Affecting Tissue Engineering Outcomes, James Dolgin, Samerender Nagam Hanumantharao, Stephen Farias, Carl G. Simon, Smitha Rao

Michigan Tech Publications

Electrospinning is a versatile tool used to produce highly customizable nonwoven nanofiber mats of various fiber diameters, pore sizes, and alignment. It is possible to create electrospun mats from synthetic polymers, biobased polymers, and combinations thereof. The post-processing of the end products can occur in many ways, such as cross-linking, enzyme linking, and thermal curing, to achieve enhanced chemical and physical properties. Such multi-factor tunability is very promising in applications such as tissue engineering, 3D organs/organoids, and cell differentiation. While the established methods involve the use of soluble small molecules, growth factors, stereolithography, and micro-patterning, electrospinning involves an inexpensive, labor …

Utilizing Robust Design To Optimize Composite Bioadhesive For Promoting Dermal Wound Repair, Rattapol Pinnaratip, Zhongtian Zhang, Ariana Smies, Pegah Kord Forooshani, Xiaoqing Tang, Rupak Rajachar, Bruce Lee

Michigan Tech Publications

Catechol-modified bioadhesives generate hydrogen peroxide (H2O2) during the process of curing. A robust design experiment was utilized to tune the H2O2 release profile and adhesive performance of a catechol-modified polyethylene glycol (PEG) containing silica particles (SiP). An L9 orthogonal array was used to determine the relative contributions of four factors (the PEG architecture, PEG concentration, phosphate-buffered saline (PBS) concentration, and SiP concentration) at three factor levels to the performance of the composite adhesive. The PEG architecture and SiP wt% contributed the most to the variation in the results associated with the H2O2 release profile, as both factors affected the crosslinking …

Anti-Inflammatory And Anti-Thrombogenic Properties Of Arterial Elastic Laminae, Jeremy Goldman, Shu Q. Liu, Brandon J. Tefft

Michigan Tech Publications

Elastic laminae, an elastin-based, layered extracellular matrix structure in the media of arteries, can inhibit leukocyte adhesion and vascular smooth muscle cell proliferation and migration, exhibiting anti-inflammatory and anti-thrombogenic properties. These properties prevent inflammatory and thrombogenic activities in the arterial media, constituting a mechanism for the maintenance of the structural integrity of the arterial wall in vascular disorders. The biological basis for these properties is the elastin-induced activation of inhibitory signaling pathways, involving the inhibitory cell receptor signal regulatory protein α (SIRPα) and Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1). The activation of these molecules causes deactivation of …

Can We Explain Machine Learning-Based Prediction For Rupture Status Assessments Of Intracranial Aneurysms?, Nan Mu, M. Rezaeitaleshmahalleh, Z. Lyu, M. Wang, J. Tang, C. M. Strother, J. J. Gemmete, A. S. Pandey, J. Jiang

Michigan Tech Publications

Although applying machine learning (ML) algorithms to rupture status assessment of intracranial aneurysms (IA) has yielded promising results, the opaqueness of some ML methods has limited their clinical translation. We presented the first explainability comparison of six commonly used ML algorithms: multivariate logistic regression (LR), support vector machine (SVM), random forest (RF), extreme gradient boosting (XGBoost), multi-layer perceptron neural network (MLPNN), and Bayesian additive regression trees (BART). A total of 112 IAs with known rupture status were selected for this study. The ML-based classification used two anatomical features, nine hemodynamic parameters, and thirteen morphologic variables. We utilized permutation feature importance, …

Fibroblast-Generated Extracellular Matrix Guides Anastomosis During Wound Healing In An Engineered Lymphatic Skin Flap, Alvis Chiu, Wenkai Jia, Yumeng Sun, Jeremy Goldman, Feng Zhao

Michigan Tech Publications

A healthy lymphatic system is required to return excess interstitial fluid back to the venous circulation. However, up to 49% of breast cancer survivors eventually develop breast cancer-related lymphedema due to lymphatic injuries from lymph node dissections or biopsies performed to treat cancer. While early-stage lymphedema can be ameliorated by manual lymph drainage, no cure exists for late-stage lymphedema when lymph vessels become completely dysfunctional. A viable late-stage treatment is the autotransplantation of functional lymphatic vessels. Here we report on a novel engineered lymphatic flap that may eventually replace the skin flaps used in vascularized lymph vessel transfers. The engineered …

An Attention Residual U-Net With Differential Preprocessing And Geometric Postprocessing: Learning How To Segment Vasculature Including Intracranial Aneurysms, Nan Mu, Zonghan Lyu, Mostafa Rezaeitaleshmahalleh, Jinshan Tang, Jingfeng Jiang

Michigan Tech Publications

Objective

Intracranial aneurysms (IA) are lethal, with high morbidity and mortality rates. Reliable, rapid, and accurate segmentation of IAs and their adjacent vasculature from medical imaging data is important to improve the clinical management of patients with IAs. However, due to the blurred boundaries and complex structure of IAs and overlapping with brain tissue or other cerebral arteries, image segmentation of IAs remains challenging. This study aimed to develop an attention residual U-Net (ARU-Net) architecture with differential preprocessing and geometric postprocessing for automatic segmentation of IAs and their adjacent arteries in conjunction with 3D rotational angiography (3DRA) images.

Methods

The …

An Assessment Of Blood Vessel Remodeling Of Nanofibrous Poly(Ε-Caprolactone) Vascular Grafts In A Rat Animal Model, Jana Horakova, Tereza Blassova, Zbynek Tonar, Connor Mccarthy, Katerina Strnadova, David Lukas, Petr Mikes, Patrick Bowen, Roger J. Guillory Ii, Megan C. Frost, Jeremy Goldman

Michigan Tech Publications

The development of an ideal vascular prosthesis represents an important challenge in terms of the treatment of cardiovascular diseases with respect to which new materials are being considered that have produced promising results following testing in animal models. This study focuses on nanofibrous polycaprolactone-based grafts assessed by means of histological techniques 10 days and 6 months following suturing as a replacement for the rat aorta. A novel stereological approach for the assessment of cellular distribution within the graft thickness was developed. The cellularization of the thickness of the graft was found to be homogeneous after 10 days and to have …