Biomaterials

Development of materials to function in living systems

Go to Research Project Index for all Research Project Categories.

Interactions of nisin with selected proteins at the liquid-liquid interface

Nisin is a small (3510 Da), positively charged amphipathic polypeptide; it is produced by Lactococcus lactis and contains dehydrated residues and lanthionine or thioether rings. It has antimicrobial activity against a wide range of gram-positive bacteria and has been widely used as a food preservative in the dairy industry. Its antimicrobial activity stems primarily from permeabilization/pore formation of the cytoplasmic membrane of target organisms, making it a promising candidate for use in formulations that could effectively transfer drugs across cellular membranes and significantly reduce microbial resistance to antibiotics. The goal of this project is to characterize the adsorption dynamics of nisin at a model oil-water interface, and to study its interactions with other macromolecules in sequential and competitive adsorption experiments, using a diverse group of proteins of varying molecular weight.

Investigators (PI is linked): Robert Y. Ofoli
Categories: Biomaterials, Colloid and Interface Science

'Green’ Biobased Sustainable Polymer and Composite Materials

This project has as its focus the goal of replacing existing petroleum-based glass fiber – polypropylene composites with eco-friendly, sustainable, bio-composites from renewable resource-based natural/bio-fibers and bio-plastics. New environmental regulations, societal concerns and growing environmental awareness have increased the demand for sustainable products and processes that are compatible with the environment. The advantages of bio-fibers over synthetic glass fibers are low cost, low density, comparable specific strength, CO2 sequesterization and biodegradabilty. In the automotive industry, natural fibers combined with petroleum-based polymer are in use. The best and most eco-friendly practice is to replace synthetic polymers with renewable resource based biodegradable plastics which is the objective of this research program. Besides selecting renewable resource based fiber, polymer, and plasticizer, a unique, environmentally benign powder process is being developed to produce bio-composites that will also be very cost-effective.

The interrelated research topics of this project include investigations of (i) synthesis and extraction of cellulose nanowhiskers from plant cellulose; (ii) innovative bio-fiber surface treatments to produce “engineered natural fibers” for combination with any thermoset or thermoplastic polymer; (iii) research into capturing cellulose and modifying it into a thermoformable plastic; (iv) methods for manufacture of bio-composites from natural fibers and bio-plastic to produce void-free and high fiber content (~ 70%) superior strength bio-composites that replace petroleum based polymers and composites; and (v) research into electrospinning of cellulose based polymers for biological sensors.

Investigators (PI is linked): Lawrence T. Drzal
Categories: Polymer Composites, Biomaterials

Alkaline and Oxidative Pretreatments of Lignocellulose

The focus of this work is to investigate novel approaches for delignification and depolymerization of lignocellulose carbohydrates by alkaline oxygen pretreatments which, in contrast to acid pretreatments, specifically target delignification. The use of alkaline-oxidative conditions as a pretreatment presents unique opportunities for co-products and separations as well as challenges from a process integration viewpoint and is an additional feature of this research project.

Investigators (PI is linked): David Hodge
http://www.chems.msu.edu/groups/hodge/  Categories: Biomaterials, Energy Production, Biobased Industrial Products, Sustainable Economy

Microcracking in Bioceramics

Microcracking in brittle materials can result in significant, at times even dramatic, changes in elastic moduli, fracture strength, fracture toughness and other physical properties. In conjunction with Professor Baumann and her students, my group is investigating microcracking and its implications for hydroxyapatite (HA), a bioceramic that is of considerable interest as an engineered bone material. Microcracking in HA potentially impacts both the mechanical properties and the biological function of HA.

Investigators (PI is linked): Eldon D. Case
Categories: Advanced Ceramic Materials, Biomaterials

Bioactive Hydroxyapatite Whisker Composite Ceramic Bone Substitutes

Hydroxyapatite (HA)-based porous ceramic constructs having mechanical properties similar to human bone are being developed. The model bone substitute is 1) osteogenic, 2) osteoinductive and 3) osteoconductive. The ideal bone substitute should also be readily available and have similar mechanical properties to native bone. While HA is not osteogenic or osteoinductive, it is osteoconductive. However, poor mechanical properties have prevented HA, or any other bioceramic, from receiving acceptance as a bone substitute. HA-based ceramics are being fabricated using a modified foaming technique and the strength assessed. Osteogenic and osteoinductive properties will be added by seeding the scaffold with osteoblasts. Such tissue engineered constructs will be the first viable synthetic alternative to currently available graft materials for repair of damaged and lost bone tissue. This research is sponsored by the National Science Foundation under grant DMR-0074439.

Investigators (PI is linked): Melissa J. Baumann
Categories: Biomaterials

Colloidal Interfaces between Biomaterials and Biological Tissue

Surface properties and how they govern cell adhesion is combined with colloidal assessment of the interfaces between bone and common biomaterials such as alumina, hydroxyapatite, bioglasses, titanium alloys, stainless steels, nickel cobalt alloys, etc. To date, the materials making contact with bone in the total hip and total knee implants have been assessed for their ability to attract mineralized bone. The colloidal properties of differing compositions of Bioglass, a bioactive bioceramic, are also being measured and compared to their ability to create a strong bone/biomaterial interface.

Investigators (PI is linked): Melissa J. Baumann
Categories: Colloid and Interface Science, Biomaterials

Engineering Surfaces and Interfaces

Self-assembly, microcontact printing, and layer-by-layer assembly techniques for surface tuning and patterning are utilized to develop new opto-electronic and bio applications. A variety of materials, such as organic and inorganic molecules, polymers, particles, and biomolecules including cells are used to prepare topologically and functionally structured surfaces for their desired purposes using novel self and directed assembly techniques.

Investigators (PI is linked): Ilsoon Lee
http://www.egr.msu.edu/~leeil/ilsoon_research.html#Ilsoon%20Lee%  Categories: Nanomaterials, Biomaterials, Electronic Materials, Polymer Composites, Structural Materials, Polymer Science and Engineering, Colloid and Interface Science, Biotechnology

Adsorption of liposomes on charged polyelectrolyte substrates (Collaborative with Worden and Lee)

One of the problems with some constructions of biomimetic interfaces using lipid bilayers is that no cushion is provided between the bilayer and the substrate to allow for full insertion of membrane proteins, enable their lateral mobility, and provide for ionic reservoirs on either side of the membrane. The deposition of polyelectrolyte multilayers provides ideal cushions for this purpose, and therefore has potential in biosensor applications. In this project, we are studying the adsorption of fluorescently labeled vesicles on charged polyelectrolyte multilayers (PDAC, PAH, PEG, SPS) deposited on glass slides, using total internal reflection fluorescence microscopy (TIRFM) and fluorescence recovery after pattern photobleaching (FRAPP) to estimate the mobility and lateral diffusion coefficients of the lipids in the bilayer. The resulting interfaces were also characterized by cyclic voltammetry (CV) and quartz crystal microbalance (QCM). This work is being done in collaboration with the research groups of Dr. Ilsoon Lee and Dr. RM Worden.

Investigators (PI is linked): Robert Y. Ofoli
Categories: Biotechnology, Colloid and Interface Science, Biomaterials, Nanomaterials

Opto-electrochemical characterization of bilayer-embedded biomacromolecules in TIR geometry

Membrane-bound enzymes and proteins can serve as ion channels and/or catalyze a variety of biological processes. These processes can be characterized by a variety of techniques, including optics and electrochemistry. In this project, we are developing surface chemistries to enable us to use ITO as an effective electrode on which bilayer lipid membranes can be deposited to provide an electrode platform for simultaneous optical and electrochemical measurements of protein activity. We also have capabilities for physical characterization of biomacromolecules (fluidity and mobility measurements) on planar as well as tethered bilayers by fluorescence recovery after pattern photobleaching (FRAPP) experiments, enabling us to do a complete study of many enzymes and proteins of medical interest.

Investigators (PI is linked): Robert Y. Ofoli
Categories: Nanomaterials, Biomaterials, Colloid and Interface Science, Biotechnology

Quantitation of biomolecular coverages at the liquid-liquid interface

We revisit work done earlier in our laboratory on estimating interfacial coverages of proteins at the oil-water interface, using total internal reflection fluorescence microscopy (TIRFM) and fluorescence photobleaching recovery (FPR). This method, first proposed by Zimmerman et. al (J. Colloid Interface Sci. 1990, 139, 268-280) for estimating surface coverages at the solid-liquid interface, is based on the principle that macromolecular interfacial coverages are related to the ratio of bulk and interfacial contributions to the total fluorescence emission detected. Interfacial coverages obtained for the adsorption of bovine serum albumin (BSA) at the oil-water interface using this technique are in the range of 0.02 to 0.3 mg/m2 in the bulk concentration region of 0.2 mg/ml to 3.5 mg/ml. These values are lower than those typically reported in the literature for similar proteins, most likely due to the low shear rates (<0.5 s-1) used in our experiments. We are investigating the effect of low shear rates on protein relaxation and spreading, and associated implications on ultimate coverages at fluid-fluid interfaces. We are also using this technique to obtain interfacial coverages at the oil-water interface for human plasma fibronectin, a large glycoprotein that has a rod-like structure and exhibits considerable flexibility. As part of this work, we are investigating fluorescence lifetimes of dye-labeled proteins at the liquid-liquid interface using two-photon excitation spectroscopy. This segment of the project is being done in collaboration with Dr. Gary J. Blanchard of the Department of Chemistry at MSU.

Investigators (PI is linked): Robert Y. Ofoli
Categories: Colloid and Interface Science, Biomaterials

Biomedical Compatibility of Ti-Al-Nb Alloys for Implant Applications

The attention given biocompatible Ti alloys has been generated by a number of important technological and economic factors. Within the last three decades a strong push has been made to replace human bone and teeth with strong, lightweight, and stiff biocompatible Ti alloys. To date the material of choice used in implants is titanium-vanadium-aluminum (Ti-V-Al) alloys because of their excellent biocompatibility and their combination of high specific strength, corrosion resistance, low density, good ductility and elastic modulus, oxidation resistance, conventional processability, fatigue strength, and fracture toughness. In particular Ti-6Al-4V(wt.%), which was initially developed as a high-temperature aerospace alloy, is a commonly used implant material due to its excellent properties and processability compared to other Ti-V-Al alloys. However, V is a potentially toxic element; therefore, other alloying elements are currently being examined. In particular substitution of niobium (Nb) for V is attractive as this does not result in degradation of several mechanical properties, and the microstructural phases present in Ti-Al-Nb alloys are similar to those in the Ti-V-Al system.

Investigators (PI is linked): Carl Boehlert
Categories: Biotechnology, Biomaterials

Self-assembled, Nanostructured Biomimetic Interfaces

Living cells efficiently perform many vital sensing, signaling, catalytic, and bioelectronic processes at the molecular scale. These processes typically occur at cell membranes, whose principal components include a bilayer lipid membrane (BLM) and membrane proteins. The BLM's nanoscale thickness (5 nm) and high electrical resistance give it unique optical and bioelectronic properties. A diverse array of membrane proteins embedded in the BLM imparts the highly specific activities exhibited by cell membranes. These activities can, in principle, be mimicked in the laboratory by reconstituting appropriate membrane proteins into artificial BLM. We are using self and directed assembly tools to fabricate functional and nanostructured biomimetic-interfaces that use lipid bilayers, membrane proteins (such as neuropathy target esterase), and other nanostructured components (e.g. polyelectrolyte multilayers) to reproduce cell-membrane processes. These systems have outstanding potential for conducting fundamental studies of nanoscale biological processes and for developing new technologies, including high-throughput drug screening systems, research tools to study membrane proteins, and high-performance biosensors.

Investigators (PI is linked): Ilsoon Lee
http://www.biomimetic.org/  Categories: Nanomaterials, Biomaterials, Polymer Composites, Structural Materials, Polymer Science and Engineering, Colloid and Interface Science, Biotechnology

Bio-Carbon Nanomaterials

Carbon nanoparticles are available in several geometries, including spherical fullerenes, cylindrical nanotubes and planar nanoplatelets. While these nanoparticles all share the same graphenic structure that imparts semiconductor properties, the diverse geometries afford a spectrum of unique chemical, electrical, magnetic, and optical properties. Composite materials containing carbon nanoparticles electrically coupled to biomolecules could yield an array of high-performance technologies. Inclusion of a biological recognition element, and any necessary cofactor or mediator, allows the composite electrode to serve as an integrated, bioactive electrode unit (i.e., bio-carbon network). This work includes (1) development of simple and rapid methods to modify and process carbon nanoparticles for self and directed assembly, (2) incorporation of the nanoparticles into bio-carbon networks, and (3) characterization of the network’s fundamental properties.

Investigators (PI is linked): Ilsoon Lee
Categories: Nanomaterials, Biomaterials, Polymer Composites, Structural Materials, Polymer Science and Engineering, Colloid and Interface Science, Biotechnology

Transport and Stability in Biocatalytic Fuel Cells

Enzyme electrocatalysts are an attractive alternative to conventional noble metals because of their high selectivity, manufacturability by fermentation techniques, and activity in environments where platinum-group metals are fouled. Until recently, however, they were not considered to be practical catalysts for energy applications because the current density, potential, and stability of the resulting cells were insufficient. We study chemical engineering aspects of the materials and structures used to implement these enzymes in electrodes, such as carbon supports, electronic mediators, and reactant transport mechanisms, in order to improve and maximize the overall performance and stability of bioelectocatalytic systems.

Investigators (PI is linked): Scott Calabrese Barton
Categories: Sustainable Economy, Biomaterials, Nanomaterials