BME 245/445 - Biomaterials Lab
Materials for Instructors
These laboratory materials were developed by Dr. Benoit for BME 245/445 (Biomaterials) at the University of Rochester. The goal of the lab component of this course is to provide students with hands-on experience in materials synthesis, characterization and modification; cell culture; histological analysis; data analysis and interpretation; and technical writing. These documents are being posted in the hopes that they will aid in the development and/or improvement of similar courses at other universities.
Lab 0: Biomaterials Lab Introduction and Safety
The first lab meeting,
Lab 0 outlines the five labs which will be performed over the course of the semester, covers basic safety rules and the expectations of the course.
Lab 1: Material Mechanical Properties
The first lab allows students to investigate how molecular precursors can be used to alter end-stage mechanical properties of hydrogel networks. The relationship between mesh-size and stiffness is particularly highlighted, and comparisons made between naturally occurring tissues and the fabricated networks. Through the associated reading, students gain an understanding of how hydrogel mechanics influence cellular behavior through mechanotransduction. Additionally, mechanical properties under tension for four common materials are analyzed. Each material’s elastic modulus, ultimate strength, toughness, and fracture behavior is compared and can be related back to their molecular structure.
Lab 2: Materials Degradation – Surface vs. Bulk
The second lab allows students to investigate how polymeric chemical structure can be used to control the degradation properties of the crosslinked network. The relationship between chemical structure and both mass loss and change in mechanical properties over time is investigated. Using microscopes, material degradation is visually tracked over time and correlated to the quantitative results from the mass/modulus aspect of the experiment. Through associated reading, students gain an understanding of how controlling material degradation can provide advantageous in numerous tissue-engineering applications.
Lab 3: Cell Culture and Cell-Material Interactions
The third lab gives students experience in sterile techniques for cell culture applications, including culturing, enumeration, and imaging mouse embryonic fibroblasts (3T3s). Within this lab, students investigate how integration of biologically derived epitopes can be used to encourage cellular adhesion and spreading. The relationship between material functionality and cell number, shape, and adhesion is studied over time.
Lab 4: Drug Delivery and Controlled Release
The fourth lab allows students to investigate how polymeric cross-linked networks can be used to controllably deliver target molecules via diffusion. The relation between cross-linking density and model drug release (bovine serum albumin) is explored. Through associated reading, students will draw comparisons between diffusion and tether mediated release strategies. The lab is posted in two forms, one that also contains a 1D diffusion model in which students can visually track then quantify the diffusion of a smaller model drug (alamar blue) through networks with different cross-linking densities.
Lab 5: Histological Examination of Biomaterials Implanted in vivo
The fifth lab allows students to learn about histological staining and examination of cells and tissues. This lab focuses on the cells prevalent in the foreign body response such as neutrophils, macrophages and foreign body giant cells, as well as cells involved in the bone healing process. Students use microscopic techniques to investigate the body’s response to surface eroding polyanhydrides that were implanted in vivo in a murine femoral defect model. While these were the histological samples available to our lab, this lab could easily be modified to study the types of samples available to you. The handout worksheet attached was developed as part of the graduate research project, and is intended to aid undergraduate students in histological interpretation and data collection.
An alternative laboratory activity is presented for the graduate students. The graduate project requires the students conduct a research project on histological methods, preparing a presentation, a written report, a handout to assist in data analysis, and assist the undergraduates in the lab section. This modification is recommended for co-listed classes, as it gives the graduate students an opportunity to delve into greater detail than they would in the traditional lab format, while also giving them an opportunity to hone their presentation and teaching skills.