Technologies

Medical Devices : Orthopedics

Technologies

Device Coating Can Selectively Bind and Deliver Biologics

UW–Madison researchers have developed coated devices that bind and deliver selected biological molecules from bodily fluids like platelet rich plasma. The methods may be carried out during surgery and used to isolate molecules from a patient’s own body.

Suitable devices include films, meshes, injectable particles or common orthopedic devices (pins, nails, plates, sutures, etc.). A coating containing phosphate, calcium or another mineral is applied under physiological temperature and pH, resulting in a structure suitable for protein binding. The device then is incubated in bodily fluid long enough to allow the biological molecule of interest to attach to the mineral coating. A suitable ionic buffer helps selectively isolate the desired molecule.

The biologic-containing device is rinsed of unwanted material and implanted into a subject. The rate at which the coating degrades can be modified to control the release of the molecules.
P110340US01

Calibrated Drill Sleeve Also Protects Soft Tissue

UW–Madison researchers have developed a separable drill sleeve that provides braking resistance and can be used with conventional orthopedic drills and bits. The sleeve protects soft tissue from the drill bit, measures the depth of the bore hole and prevents the drill from plunging through the far side of the bone.

The sleeve features upper and lower tube segments. At the lower end is a base that contacts bone and provides a passage for the drill bit. The upper segment is able to slide relative to the base and indicate bore depth. In between the segments is a fluid damper that resists sudden acceleration of the drill bit as it pushes beyond the bone.
P120364US01

Biomaterials That Modulate Stem Cell Behavior and Osteogenesis

UW–Madison researchers have developed methods and biomaterials that can significantly enhance stem cell proliferation and differentiation or promote osteogenesis. The biomaterials include biomolecular ligands that specifically and non-covalently bind to and sequester endogenous proteoglycans. The researchers found that this sequestration was sufficient to modulate stem cell behavior as well as osteogenesis.

The biomaterials may consist of self-assembled monolayers (SAMs) that include a substrate and a synthetic peptide. Suitable substrates include metal-containing substrates, synthetic hydrogels, polymers from natural sources or mineralized materials like hydroxyapatite. The ligands may include a heparin-binding peptide, chrondroitin sulfate-binding peptide, hyaluronic acid glycosaminoglycan-binding peptide, cell-adhesion peptide or synthetic peptide.
P100257US02

Bone Tissue Regeneration System That Provides Spatial and Temporal Control Over the Release of Growth Factors

UW–Madison researchers have developed a tissue regeneration system that utilizes porous scaffolds to localize and temporally control the release of multiple growth factors.  In this system, porous beta tricalcium phosphate (β-TCP) templates are coated with one or more extracellular matrix layers.  The layers include at least one thin, degradable mineral layer that is similar to bone mineral.  Because the coating process does not require high temperatures or organic solvents, biologically active growth factors such as vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) can be incorporated in the layers. 

To control dissolution order, and ultimately, delivery of the biologically active molecules, multiple distinct layers are deposited on the β-TCP scaffold.  Each layer may contain one or more active biomolecules and is designed to dissolve at a separate rate. As the matrix material gradually breaks down, the growth factors are delivered sequentially.  This provides temporal control of growth factor signaling, thereby directing the activities of associated cells, to enable the growth of new bone tissue.
P09200US

Biologically Active Sutures Enhance Tissue Healing Following Surgical Procedures

UW-Madison researchers have developed a method of coating the surface of commonly used suture materials and other orthopedic devices with a biodegradable layer containing molecules that can induce tissue growth and limit bacterial infection.  The rate at which the coating degrades can be modified to control the release of the molecules. 

Specifically, a suture is coated with a mineral layer under physiological temperature and pH, resulting in a nano-porous structure with high surface area for protein binding.  Then biologically active molecules are bound to the surface of the suture for subsequent release in vivo.  Protein binding can be achieved rapidly in the operating room, and the process can be adapted to enable the incorporation of a wide range of other therapeutic molecules, in addition to proteins.
P09201US

An Orthopedic Implant Coating for Enhanced Bone Growth

UW-Madison researchers have developed a biomaterial-based approach for directing bone regeneration to treat bony defects. This approach uses a biologically active calcium phosphate-based coating to target and control delivery of a bound growth factor molecule capable of inducing bone growth. This coating can be applied to all bioresorbable materials commonly used in orthopedic surgery, including nails, pins, anchors, screws, plates and scaffolds.

Under physiological conditions, the solubility of different calcium phosphate materials can vary by more than 5000 percent. To take advantage of this broad range of dissolution rates, the coating consists of several layers of calcium phosphate materials with distinct dissolution profiles. Bone growth factors are bound to the calcium phosphate and released based on the dissolution profile of each layer. To provide a delayed release, calcium phosphate layers that do not contain a growth factor or drug can be incorporated into the coating. This approach can be easily integrated with existing implants and surgical procedures in clinics.
P07031US

Bioactive and Biocompatible Copolymers for Use in Medical Implants

UW-Madison researchers have combined polyurethane with naturally-occurring glycosaminoglycans, such as hyaluronic acid and dermatan sulfate, to create a new class of biomaterials with improved properties. The resulting copolymers combine the elasticity and mechanical strength of polyurethane with the biological properties of glycosaminoglycans. They have excellent hemocompatibility and biocompatibility for use in medical implant devices.

In addition, selecting the appropriate glycosaminoglycan allows the biological properties of the copolymer to be tailored to elicit specific physiological responses. For instance, the polyurethane-dermatan sulfate copolymer formulation is non-biofouling, while one version of the polyurethane-hyaluronic acid copolymer permits the growth of endothelial cells only.
P07185US

Biomaterial Scaffolds for the Repair and Regeneration of Intervertebral Discs and Articulating Joints

Researchers from UW-Madison and elsewhere have developed methods for engineering and preparing scaffolds for repairing intervertebral discs and articulating joints.  These scaffolds have internal porous architectures that meet the need for mechanical stiffness and strength as well as connected porosity for cell migration and tissue regeneration. 

The methods utilize images prepared with magnetic resonance (MR) or a combination of MR and computed tomography (CT) as a template for creating the scaffolds as well as the fixation for the scaffolding into adjacent tissue or bone.  Their advantages include the ability to design microstructures that mimic intervertebral load carrying capability and the potential to provide directed nutrients to migrated cells within the disc.  Furthermore, the ability to create structures that can regrow natural tissue could be an improvement upon current artificial discs made of synthetic materials which are subject to greater wear and tear.
P08447US

Injection Molding of Biodegradable Tissue Engineering Scaffolds

UW-Madison researchers have developed a simple and inexpensive method of mass producing biodegradable structures for tissue engineering and drug delivery applications. The method starts with a composite blend of a salt, a water-soluble polymer and a biodegradable polymer. A foaming agent and/or supercritical fluid may be added to the composite, which is injected into a mold to form components with complex geometries. After molding, the salt and water-soluble polymer are removed to result in a low density, biodegradable structure.
P07200US

Device to Facilitate Controlled Rotation of the Cervical Spine

UW-Madison researchers have developed an improved cervical spine positioning device for use in medical imaging. This device consists of concentric rings mounted between side supports. Bearing surfaces between the inner and outer rings facilitate isocentric rotation, while the two pivot swivel joints on either side of the rings enable flexion/extension motion. The device utilizes friction-induced stopping mechanisms to allow the user to accurately position the patient’s neck and easily reproduce positioning for multiple scans.
P05247US