Paul T. Hamilton

Improved bone morphogenetic protein-2 retention in an injectable collagen matrix using bifunctional peptides.

To promote healing of many orthopedic injuries, tissue engineering approaches are being developed that combine growth factors such as Bone Morphogenetic Proteins (BMP) with biomaterial carriers. Although these technologies have shown great promise, they still face limitations. We describe a generalized approach to create target-specific modular peptides that bind growth factors to implantable biomaterials. These bifunctional peptide coatings provide a novel way to modulate biology on the surface of an implant. Using phage display techniques, we have identified peptides that bind with high affinity to BMP-2. The peptides that bind to BMP-2 fall into two different sequence clusters. The first cluster of peptide sequences contains the motif W-X-X-F-X-X-L (where X can be any amino acid) and the second cluster contains the motif F-P-L-K-G. We have synthesized bifunctional peptide linkers that contain BMP-2 and collagen-binding domains. Using a rat ectopic bone formation model, we have injected rhBMP-2 into a collagen matrix with or without a bifunctional BMP-2: collagen peptide (BC-1). The presence of BC-1 significantly increased osteogenic cellular activity, the area of bone formed, and bone maturity at the site of injection. Our results suggest that bifunctional peptides that can simultaneously bind to a growth factor and an implantable biomaterial can be used to control the delivery and release of growth factors at the site of implantation.

Phage display and structural studies reveal plasticity in substrate specificity of caspase-3a from zebrafish

The regulation of caspase‐3 enzyme activity is a vital process in cell fate decisions leading to cell differentiation and tissue development or to apoptosis. The zebrafish, Danio rerio, has become an increasingly popular animal model to study several human diseases because of their transparent embryos, short reproductive cycles, and ease of drug administration. While apoptosis is an evolutionarily conserved process in metazoans, little is known about caspases from zebrafish, particularly regarding substrate specificity and allosteric regulation compared to the human caspases. We cloned zebrafish caspase‐3a (casp3a) and examined substrate specificity of the recombinant protein, Casp3a, compared to human caspase‐3 (CASP3) by utilizing M13 bacteriophage substrate libraries that incorporated either random amino acids at P5‐P1′ or aspartate fixed at P1. The results show a preference for the tetrapeptide sequence DNLD for both enzymes, but the P4 position of zebrafish Casp3a also accommodates valine equally well. We determined the structure of zebrafish Casp3a to 2.28Å resolution by X‐ray crystallography, and when combined with molecular dynamics simulations, the results suggest that a limited number of amino acid substitutions near the active site result in plasticity of the S4 sub‐site by increasing flexibility of one active site loop and by affecting hydrogen‐bonding with substrate. The data show that zebrafish Casp3a exhibits a broader substrate portfolio, suggesting overlap with the functions of caspase‐6 in zebrafish development.

Cooperative Learning through Team-Based Projects in the Biotechnology Industry †

We have developed a cooperative-learning, case studies project model that has teams of students working with biotechnology professionals on company-specific problems. These semester-long, team-based projects can be used effectively to provide students with valuable skills in an industry environment and experience addressing real issues faced by biotechnology companies. Using peer-evaluations, we have seen improvement in students’ professional skills such as time-management, quality of work, and level of contribution over multiple semesters. This model of team-based, industry-sponsored projects could be implemented in other college and university courses/programs to promote professional skills and expose students to an industry setting.

Preparing Science-Trained Professionals for the Biotechnology Industry: A Ten-Year Perspective on a Professional Science Master’s Program

The biotechnology industry has a need for business-savvy scientists; however, this is not the way scientists are traditionally trained at universities and colleges. To address this need, universities have developed Professional Science Masters (PSM) degree programs that offer advanced training in a technical field along with professional skills development through team-based projects and internships. Nearly ten years ago, the Department of Microbiology at NCSU started a PSM program in Microbial Biotechnology (MMB). This article provides an overview of the MMB program, and shares some of the lessons that we have learned.

An Internship May Not Be Enough: Enhancing Bioscience Industry Job Readiness through Practicum Experiences †

In contrast to the narrowing of options in academic careers, the bioscience industry offers robust employment opportunities for STEM-trained workers, especially those who display both scientific and business talent. Unfortunately, traditional science programs typically lack curricular features that develop this type of worker. The North Carolina State University Master of Microbial Biotechnology (MMB) program facilitates industry-specific experiential learning to fill this training gap. Similar programs often rely on a single industry internship to provide students relevant work experience, but completion of one internship might not suffice to position students for employment in a highly competitive job market. The MMB program requires students to complete an internship and three practicum projects in an industry setting, to promote development of key skills in a variety of areas, to build confidence in the ability to perform initial job duties, and to establish a more extensive work history in industry. In this Perspective we discuss an unmet need in undergraduate and graduate STEM education that can be filled by incorporating a similar set of industry-specific work experiences for students who desire to transition from academe into the life science industry.