Making Space for Other Voices: Hands-On, Human-Centered Design Delivered Online.

During the spring of 2020, due to the COVID-19 pandemic, it was necessary to rapidly translate a new human-centered design studio course for first-year biomedical engineering students from a face-to-face delivery mode to a remote delivery mode. In addition to disrupting plans for hands-on design prototyping experiences, stay-at-home orders associated with the pandemic disrupted plans for students to interact substantively and empathetically with potential users, which is the heart of human-centered design. The challenge was therefore to provide students without ready access to machine shops, 3D printing, or other people with some form of the educational experiences promised in the course syllabus.

Operating curves to characterize the contraction of fibroblast-seeded collagen gel/collagen fiber composite biomaterials: effect of fiber mass.

Background: Collagen is a well-established and important biomaterial that could be used to help meet significant medical needs for various soft-tissue replacements. Many efforts to create engineered soft-tissue constructs by seeding cells within collagen gels have been hampered because constituent cells contract collagen gels over time, resulting in a construct that is only a fraction of the original size and that contains a cell population that has suffered a large degree of cell death. However, the presence of embedded short collagen fibers has been shown to significantly limit contraction and dramatically enhance permeability in fibroblast-seeded collagen gels.

Collagen composite biomaterials resist contraction while allowing development of adipocytic soft tissue in vitro.

Soft tissue defects resulting from tumor resection or trauma require surgery to restore the body's contours. Because autologous tissues or synthetic implant reconstructions can be less than ideal, engineered tissues produced in vitro are being developed as alternatives. Collagen gels have been proposed for this application because they are biocompatible and can be shaped to fill a specific defect.

Development of ligament-like structural organization and properties in cell-seeded collagen scaffolds in vitro.

Acute anterior cruciate ligament (ACL) injuries lead to poor joint function, instability, and eventually osteoarthritis if left untreated. Current surgical treatment options are not ideal; however, tissue engineering may provide mechanically sound, biocompatible reconstructions. Collagen fiber scaffolds were combined with fibroblast-seeded collagen gels and maintained in culture for up to 20 days.

Comparison of in vitro mineralization by murine embryonic and adult stem cells cultured in an osteogenic medium.

Nearly half a million bone-grafting procedures occurred in the United States in the year 2000. Tissue-engineered bone substitutes may mitigate difficulties associated with current grafting options. Embryonic stem cells (ESCs) could be a potential cell source for bone substitutes; however, direct comparisons between ESCs and other cell sources are lacking.

"Culture shock" from the bone cell's perspective: emulating physiological conditions for mechanobiological investigations.

Bone physiology can be examined on multiple length scales. Results of cell-level studies, typically carried out in vitro, are often extrapolated to attempt to understand tissue and organ physiology. Results of organ- or organism-level studies are often analyzed to deduce the state(s) of the cells within the larger system(s).

Solvent effects on the microstructure and properties of 75/25 poly(D,L-lactide-co-glycolide) tissue scaffolds.

Poly(lactide-co-glycolide) (PLGA) is used in many biomedical applications because it is biodegradable, biocompatible, and FDA approved. PLGA can also be processed into porous tissue scaffolds, often through the use of organic solvents. A static light scattering experiment showed that 75/25 PLGA is well solvated in acetone and methylene chloride, but forms aggregates in chloroform.

Opinions and trends in biomaterials education: report of a 2003 Society for Biomaterials survey.

The Society for Biomaterials (SFB) aims to serve its members through acting as a forum for the exchange of information and ideas. To aid in the practical development of the SFB and more specifically biomaterials education, all active, associate, and student members were surveyed. In general, the survey asked questions regarding respondent demographics, experiences and activities with the SFB, and opinions about biomaterials education.

Pressure gradient, not exposure duration, determines the extent of epithelial cell damage in a model of pulmonary airway reopening.

The reduction of tidal volume during mechanical ventilation has been shown to reduce mortality of patients with acute respiratory distress syndrome, but epithelial cell injury can still result from mechanical stresses imposed by the opening of occluded airways. To study these stresses, a fluid-filled parallel-plate flow chamber lined with epithelial cells was used as an idealized model of an occluded airway. Airway reopening was modeled by the progression of a semi-infinite bubble of air through the length of the channel, which cleared the fluid.

A device for long term, in vitro loading of three-dimensional natural and engineered tissues.

In vitro studies of mechanical loads applied to three-dimensional tissue constructs are important to the design and production of functional, engineered bone tissue. This study reports the development and characterization of a mechanical device capable of subjecting a three-dimensional section of natural or engineered tissue to precise, reproducible four-point bending deformations over a range of programmable magnitudes and frequencies. To test the biological and mechanical capabilities of the system, a low-cycle (360 cycles/day), medium-range strain (2500 microstrain), long-term (16 day) loading regime was applied to rat bone marrow stromal cells cultured in porous DL-polylactic acid scaffolds.

Mechanical characterization of collagen fibers and scaffolds for tissue engineering.

Engineered tissues must utilize scaffolding biomaterials that support desired cellular functions and possess or can develop appropriate mechanical characteristics. This study assessed properties of collagen as a scaffolding biomaterial for ligament replacements. Mechanical properties of extruded bovine achilles tendon collagen fibers were significantly affected by fiber diameter, with smaller fibers displaying higher tangent moduli and peak stresses.

In vitro mineralization studies with substrate-immobilized bone morphogenetic protein peptides.

Understanding the factors that control osteoblastic behavior is centrally important in establishment of successful osseointegration. Pharmacogenetic control of the osteoblast to increase the mineral content around dental implants may offer a unique advantage to clinicians in improving osseointegration success and decreasing time before mechanical loading. This in vitro pilot study has screened for bioactive peptides derived from bone morphogenetic protein 7 (BMP-7) (also called osteogenic protein 1 [OP-1]).

Research report: learning styles of biomedical engineering students.

Examining students' learning styles can yield information useful to the design of learning activities, courses, and curricula. A variety of measures have been used to characterize learning styles, but the literature contains little information specific to biomedical engineering (BMEN) students. We, therefore, utilized Felder's Index of Learning Styles to investigate the learning style preferences of BMEN students at Tulane University.

Mechanisms of surface-tension-induced epithelial cell damage in a model of pulmonary airway reopening.

Airway collapse and reopening due to mechanical ventilation exerts mechanical stress on airway walls and injures surfactant-compromised lungs. The reopening of a collapsed airway was modeled experimentally and computationally by the progression of a semi-infinite bubble in a narrow fluid-occluded channel. The extent of injury caused by bubble progression to pulmonary epithelial cells lining the channel was evaluated.

A jet impingement investigation of osteoblastic cell adhesion.

When designing dental and orthopedic implants, it is important to consider phenomena occurring at the microscopic level, particularly at the bone-implant interface. The presence of hard tissue at this interface is essential to implant viability. The integrity of this tissue-biomaterial interface is dependent on appropriate osteoblast functions (adhesion, matrix deposition, etc.