Recent Patents on Biomedical Engineering (Discontinued) - Volume 1, Issue 2, 2008

Fractionated and low molecular weight heparins comprise the main class of anticoagulants used to prevent and treat thrombosis in patients through catalysis of enzyme inhibition by plasma antithrombin. However, clinical application of heparin suffers several limitations including: reduced venous half-life, uncontrolled anticoagulant effects, hemorrhagic complications and biophysical problems. A novel covalent antithrombin-heparin (ATH) complex has recently been created that overcomes heparin's deficiencies. Historical patent literature and prior art reveal a progression of earlier attempts to link heparin to antithrombin that yielded products with various degrees of functionality. Relative to heparin, the present ATH invention of matter has a vastly increased bioavailability of circulating complex, significantly increased antithrombotic activity and superior ability to neutralize clot-bound coagulation enzymes. Recently issued ATH patents describe ATH-coatings on surfaces of devices that come into contact with blood. These ATH-covered products are vastly improved in prevention of device malfunction due to thrombus formation. There is a large market related to the biomaterial coatings industry that may benefit from development of blood-contacting products containing surface-bound ATH.

Cell or organ printing is any technology that enables a user to deposit precise patterns of living cells or cell aggregates throughout three dimensional (3D) tissue engineering scaffolds. Traditional tissue engineering approaches utilize random cell seeding (flooding) of porous scaffolds to promote cell attachment. While this approach does allow cells to diffuse and attach throughout macroscopic scaffolds, there are both biological and material limitations of this approach, namely the inability to mimic the cellular/molecular heterogeneity and structure (vascularization, sinuses, etc.) found in natural tissue. Cell printing offers the unique possibility of creating tissue scaffolds with pre-built cellular/molecular heterogeneity and structure through layer-by-layer fabrication. The aim of this review is to illustrate the different approaches to building tissue scaffolds via cell printing, describe the specific cell printers in the peer-reviewed and patent literature with their demonstrated capabilities, and then discuss the future of these technologies with respect to important biomedical applications such as tissue engineering, organ replacement and tissue microdissection.

In comparison to two-dimensional (2D), three-dimensional (3D) cell culture systems are believed to more closely emulate in vivo conditions, and thus are becoming popular models for screening in drug discovery and other studies related to human diseases. The rising importance of 3D cell cultures is reflected in the four-fold increase of related publications between 1996 and 2006. This paper reviews US patents issued that underpin the practical utilization of 3D cell culture systems. Patents are grouped according to the materials used including synthetic and natural polymer, inorganic/nonmetallic materials, and specialized medium. While earlier applications of 3D cell culture systems relied heavily on their ability to prolong cell growth and promote cell propagation, recent applications mainly focus on in vivo emulation attributes. In all cases the 3D claims are based on morphology, which may not be sufficient. Genomic and cellular functional assays to substantiate these claims are needed.

Injectable fillers for both bone and soft-tissue are used for a range of medical applications from aesthetic rejuvenation through space filling to functional restoration of structural tissues. Fillers can be classed as biological, synthetic, biosynthetic or composite materials on the basis of their primary components. Most commonly used in practice are the biological fillers such as collagen and hyaluronic acid, however synthetic and biosynthetic fillers are the topic of intense research and patenting activity. Composite fillers are typically used in bone filling applications with hydroxyapatite ceramic components being combined with synthetic or biological carrier polymers. More recent patenting activity appears to focus on biosynthetic and composite fillers with some patents proposing that cell incorporation in some of these fillers is a possible approach to improving their performance. The next challenge will be in translating new ideas for biosynthetic and composite fillers as well as fillers incorporating functional cells into engineered medical products.

With continuously increasing numbers of patients with congestive heart failure (CHF), several alternatives to conventional medical treatment have been developed. Mechanical circulatory support (MCS) systems in the form of ventricular assist devices or artificial hearts are among the widely accepted therapy options. To compensate for the shortage of donor organs, major improvements have been made in MCS systems. However, these systems have several limitations that may add to the patient's morbidity and mortality. The aim of this article is to review patents describing MCS devices disclosed in the last two years. Most of the patents disclosed within this time frame were related to continuous flow pumps. The majority of the inventions aimed at minimizing pump size, infection complications, costs, hemolytic properties, thrombogenicity, and power consumption of these devices. Meanwhile, some other inventors focused on building appropriate control systems for continuous flow pumps or ideal cannulae that could avoid ventricular collapse and suction. The current MCS technology still has much room for improvement through such innovations. The development of a viable, long-term MCS system still remains the ultimate goal.

Cardiac Resynchronization Therapy (CRT) is a medical procedure which has revolutionized treatment for patients with heart failure. The procedure was first described in 1994. Its benefit relies on the fact that many patients with heart failure have uncoordinated contraction of the left ventricle which results from abnormal electrical activation patterns. This gives rise to inefficient mechanical function. CRT involves transvenous placement of an electrical pacing lead in a coronary vein to the surface of the left ventricle. This is connected to a cardiac pacemaker in order to recoordinate the heart's contractile function. This represents a huge breakthrough in medicine and biomedical science and is the focus of great interest in research and development of new technologies. The purpose of this review is to illustrate recent inventions patented in this rapidly evolving field. We will focus on device technology, lead delivery systems and methods of optimising pacemaker function. We will also discuss current and future developments in cardiac resynchronization therapy.

Enzyme replacement therapy is the only authorized method for treating lysosomal storage disorders. During the last ten years, this method has been demonstrated to be both safe and effective for the treatment of many lysosomal storage disorder patients. Recent advances in enzyme replacement therapy address the pressing issues for this therapeutic strategy: high cost and ineffectiveness in certain disease manifestations. To address the costs of enzyme replacement therapy, a variety of expression systems including plant and insect cells have been developed for production of recombinant lysosomal enzymes in a more affordable manner. In addition, various chemical and biological strategies have been used to enhance enzyme activity and lysosome targeting efficiency. The range of diseases treatable with enzyme replacement therapy has been expanded by the development of expression and purification processes for unique lysosomal enzymes. Novel administration methods have also been developed which has been recently patented to effectively deliver lysosomal enzymes to brain tissues that are inaccessible by traditional intravenous administration. Because of these advances, together with the development of gene expression technology and metabolic engineering, more lysosomal storage disorder patients are expected to benefit from enzyme replacement therapy.

To repair dental defects with ceramics, prior to the mid-1960s, dental restorations such as ceramic crowns were fabricated using porcelain. In the 1980s, glass-ceramic dental materials were developed. In recent years, by combining the CAD/CAM system with elements of dental restoration technology, it is possible to make crowns and 3-unit anterior bridges through copy-milling cores from industrially partially sintered alumina blanks and glass-infiltrated technology. Over the last decades the developments of dental restoration using ceramic have resulted in the filing of many patents. The aim of this paper is to review these patents, categorize them focusing on the three parts which include dental restoration materials and their composition, the preparation of the raw materials and the fabrication of the restorations including relative technology and apparatus. In the end, we discuss the tendency of the dental restoration, the work to be improved and have a discussion from a systematic perspective. This review article also includes relevant patents.

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