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The undergraduate Bioengineering Program at Lehigh University was established as part of the university's Bioscience and Biotechnology Initiative with support from the National Science Foundation through a grant from its Division of Engineering Education and Centers (EEC). The objective here is to describe the program development and implementation, as well as the challenges encountered. Bioengineering at Lehigh was designed as an interdisciplinary program, with an emphasis on experiential learning, entrepreneurship, and innovation. In this light, the goals established for the program implementation were focused on recruiting students, developing a rigorous curriculum, equipping laboratories, and fostering industrial partnerships. The curriculum initially had three key components: a core of basic requirements, three tracks allowing students to specialize within a field of bioengineering, and experiential learning. The key challenges faced are balancing breadth and depth of a curriculum in a diverse field, improving experiential learning opportunities, implementing changes while maintaining stability, and handling operations as a new program rather than as an established department. The effectiveness of these strategies has been assessed on an ongoing basis. For example, an integrated recruitment strategy was used to encourage student enrollment, the results of which were measured through surveys and admissions data. Requiring students to select one of the three tracks, which are Biopharmaceutical Engineering, Cell and Tissue Engineering, and Bioelectronics and Biophotonics, each with an advanced laboratory course, added depth to the curriculum. Based on several sources of feedback, numerous changes have been made to the curriculum, including the addition of more bioengineering courses, especially advanced electives. The incorporation of Integrated Product Development (IPD), which was already an established hallmark program at Lehigh, into bioengineering, was a major program change that enhanced the hands-on learning and innovation opportunities. Implementing such changes, and managing them effectively, have been necessary to maintain program stability.

Byline: H. Daniel Ou-Yang, Department of Physics and Bioengineering University, Bethlehem, Pennsylvania 18015; email: hdo0@lehigh.edu, Department of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015; email: miw206@lehigh.edu; Ming-Tzo Wei, Department of Bioengineering, Lehigh University, Bethlehem, Pennsylvania 18015; email: miw206@lehigh.edu Keywords: microrheology, viscoelasticity, nonequilibrium thermodynamics, motor proteins, DNA, actin filaments, focal adhesion complexes, cytoskeleton Abstract The mechanical properties of cells are crucial for cell sensing and reaction to mechanical environments. This review describes the basic principles of optical tweezers and their use as force sensors for studying the mechanical properties of biological systems. It covers experiments of four groups of biological systems arranged by increasing complexity: (a) packaging DNA into viral capsids by bacteriophage portal motors and the dynamical stiffness of DNA upon protein binding, (b) actin-coated giant vesicles and the myosin-II embedded actin polymer network, (c) suspension cells, and (d) adhesion cells. These examples demonstrate how optical tweezers have been used to improve the understanding of the mechanical properties of biological systems at subcellular and molecular levels.

Background: Titanium dioxide (TiO2) is one of the most common nanoparticles found in industry ranging from food additives to energy generation. Approximately four million tons of TiO2 particles are produced worldwide each year with approximately 3000 tons being produced in nanoparticulate form, hence exposure to these particles is almost certain. Results: Even though TiO2 is also used as an anti-bacterial agent in combination with UV, we have found that, in the absence of UV, exposure of HeLa cells to TiO2 nanoparticles significantly increased their risk of bacterial invasion. HeLa cells cultured with 0.1 mg/ml rutile and anatase TiO2 nanoparticles for 24 h prior to exposure to bacteria had 350 and 250 % respectively more bacteria per cell. The increase was attributed to bacterial polysaccharides absorption on TiO2 NPs, increased extracellular LDH, and changes in the mechanical response of the cell membrane. On the other hand, macrophages exposed to TiO2 particles ingested 40 % fewer bacteria, further increasing the risk of infection. Conclusions: In combination, these two factors raise serious concerns regarding the impact of exposure to TiO2 nanoparticles on the ability of organisms to resist bacterial infection. [ABSTRACT FROM AUTHOR]

Endothelial cells form the inner lining of blood vessels and are exposed to various factors like hemodynamic conditions (shear stress, laminar, and turbulent flow), biochemical signals (cytokines), and communication with other cell types (smooth muscle cells, monocytes, platelets, etc.). Blood vessel functions are regulated by interactions among these factors. The occurrence of a pathological condition would lead to localized upregulation of cell adhesion molecules on the endothelial lining of the blood vessel. This process is promoted by circulating cytokines such as tumor necrosis factor-alpha, which leads to expression of intercellular adhesion molecule-1 (ICAM-1) on the endothelial cell surface among other molecules. ICAM-1 is critical in regulating endothelial cell layer dynamic integrity and cytoskeletal remodeling and also mediates direct cell-cell interactions as part of inflammatory responses and wound healing. In this study, we developed a biomimetic blood vessel model by culturing confluent, flow aligned, endothelial cells in a microfluidic platform, and performed real time in situ characterization of flow mediated localized pro-inflammatory endothelial activation. The model mimics the physiological phenomenon of cytokine activation of endothelium from the tissue side and studies the heterogeneity in localized surface ICAM-1 expression and F-actin arrangement. Fluorescent antibody coated particles were used as imaging probes for identifying endothelial cell surface ICAM-1 expression. The binding properties of particles were evaluated under flow for two different particle sizes and antibody coating densities. This allowed the investigation of spatial resolution and accessibility of ICAM-1 molecules expressed on the endothelial cells, along with their sensitivity in receptor-ligand recognition and binding. This work has developed an in vitro blood vessel model that can integrate various heterogeneous factors to effectively mimic a complex endothelial microenvironment and can be potentially applied for relevant blood vessel mechanobiology studies. [ABSTRACT FROM AUTHOR]

We use optical tweezers-based dielectrophoresis (DEP) force spectroscopy to investigate the roles of the electrical double layer in the AC dielectric response of an individual colloidal particle in an aqueous medium. Specifically, we measure the DEP crossover frequency as a function of particles size, medium viscosity, and temperature. Experimental results were compared to low frequency relaxation mechanisms predicted by Schwarz, demonstrating the dielectrophoretic responses in the frequency range between 10 kHz and 1 MHz were dominated by counterion diffusion within the electric double layer. [ABSTRACT FROM AUTHOR]