Biomaterials.info - Resources for Engineers

Record 1001 to 1020

Biomaterials for artificial joints
Amstutz, H. C. (1973), Orthop Clin North Am 4(2): 235-48.

Biomaterials for blood tubing: the application of plasticised poly(vinyl chloride)
Blass, C. R., C. Jones, et al. (1992), Int J Artif Organs 15(4): 200-3.

Biomaterials for blood-contacting applications
Courtney, J. M., N. M. Lamba, et al. (1994), Biomaterials 15(10): 737-44.
Abstract: Consideration of biomaterials for blood-contacting applications should take into account blood-biomaterial interactions, factors influencing the blood response and evaluation procedures. Examination of blood-biomaterial interactions indicates that relevant features are protein adsorption, platelet reactions, intrinsic coagulation, fibrinolytic activity, erythrocytes, leucocytes and complement activation. Factors influencing the blood response to a biomaterial in clinical application are the biomaterial structure, the presence of an antithrombotic agent, the patient status as determined by the disease and drug therapy, and the nature of the application. Evaluation options for biomaterials are clinical, in vivo, ex vivo and in vitro, with ex vivo and in vitro procedures relevant for biomaterial development.

Biomaterials for digestive surgery
Aprahamian, M. (1993), Biomaterials 14(7): 556.

Biomaterials for drug delivery systems
Buckles, R. G. (1983), J Biomed Mater Res 17(1): 109-28.
Abstract: Drug delivery systems have unusual materials requirements which derive mainly from their therapeutic role: to administer drugs over prolonged periods of time at rates that are independent of patient-to-patient variables. The chemical nature of the surfaces of such devices may stimulate biorejection processes which can be enhanced or suppressed by the simultaneous presence of the drug that is being administered. Selection of materials for such systems is further complicated by the need for compatibility with the drug contained within the system. A review of selected drug delivery systems is presented. This leads to a definition of the technologies required to develop successfully such systems as well as to categorize the classes of drug delivery systems available to the therapist. A summary of the applications of drug delivery systems will also be presented. There are five major challenges to the biomaterials scientist: (1) how to minimize the influence on delivery rate of the transient biological response that accompanies implantation of any object; (2) how to select a composition, size, shape, and flexibility that optimizes biocompatibility; (3) how to make an intravascular delivery system that will retain long-term functionality; (4) how to make a percutaneous lead for those delivery systems that cannot be implanted but which must retain functionality for extended periods; and (5) how to make biosensors of adequate compatibility and stability to use with the ultimate drug delivery system-a system that operates with feedback control.

Biomaterials for facial bone augmentation: comparative studies
Homsy, C. A. (1988), J Biomed Mater Res 22(3 Suppl): 351-6.

Biomaterials for gene delivery: atelocollagen-mediated controlled release of molecular medicines
Ochiya, T., S. Nagahara, et al. (2001), Curr Gene Ther 1(1): 31-52.
Abstract: Over the last decade, increasing attention has been paid to the development of systems to deliver drugs for long periods at controlled rates. Some of these systems can deliver drugs continuously for over one year. However, little effort has been given to developing systems for the controlled release of nucleic acids. Recently, a novel gene transfer method which allows prolonged release and expression of plasmid DNA in vivo in normal adult animals was established. In this system, a biocompatible natural polymer such as collagen or its derivatives acts as the carrier for the delivery of DNA vectors. The biomaterial carrying the plasmid DNA was administered into animals and, once introduced, gradually released plasmid DNA in vivo. A single injection of plasmid DNA/biomaterial produced physiologically significant levels of gene-encoding proteins in the local/systemic circulation of animals and resulted in prolonged biological effects. These results suggest that the biomaterials carrying plasmid DNA may enhance the clinical potency of plasmid-based gene transfer, facilitating a more effective and long-term use of naked plasmid vectors for gene therapy. Furthermore, the biomaterials can be removed surgically, minimizing the effect of gene products if some unexpected side effects should be observed after application. The application of these systems to expand the bioavailability of molecular medicine, including antisense oligonucleotides and adenovirus vectors, and to aid in stem cell transplantation in the context of DNA-based tissue engineering will be discussed.

Biomaterials for hemodialysis access
Johansen, K., D. Lyman, et al. (1994), Blood Purif 12(1): 73-7.
Abstract: While the optimal vascular conduit for hemodialysis is undeniably an arterialized autogenous subcutaneous vein, only a minority of end-stage renal disease patients can count on such access: the remainder require implantation of a biomaterial conduit. This paper will briefly survey current biografts used for hemodialysis access, with an emphasis on their known limitations, and will delineate the questions to be asked--and answered--in the development of optimal dialysis access grafts.

Biomaterials for implantable middle ear hearing devices
Dormer, K. J. and R. Z. Gan (2001), Otolaryngol Clin North Am 34(2): 289-97.
Abstract: The use of biomaterials to ameliorate the effects of diseases dates back centuries to the ancient Greeks and Chinese. In the twentieth century, the use of synthetic and natural materials rapidly increased as clinicians developed problem-solving strategies. From replacement prostheses, to structural polymers, to the controlled release of engineered proteins into the body, to the present-day tissue engineering, biomaterials have transformed medicine. The ear is no exception. Various alloplastic and homograft biomaterials have been used to restore hearing with ossicular replacement prostheses, cochlear implants, and most recently, implantable middle ear devices. This article updates an earlier review of biomaterials used in implantable middle ear devices and focuses on biomaterials used in implantable middle ear devices currently under development or in clinical trials.

Biomaterials for implanted closed loop insulin delivery system: a review
Wilkins, E. and W. Radford (1990), Biosens Bioelectron 5(3): 167-213.
Abstract: The potential of five different groups of materials--carbons, glass and ceramics, polymers, hydrogels and collagen--as biomaterials in artificial implant applications is examined. In addition to the physical and/or structural properties of these materials, the blood and tissue responses to implants made of these biomaterials for various applications are presented. Emphasis is placed on materials related to the intended application; as catheter tips and biosensors for glucose to be used in conjunction with an implantable insulin delivery system as a complete artificial pancreas.

Biomaterials for mediation of chemical and biological warfare agents
Russell, A. J., J. A. Berberich, et al. (2003), Annu Rev Biomed Eng 5: 1-27.
Abstract: Recent events have emphasized the threat from chemical and biological warfare agents. Within the efforts to counter this threat, the biocatalytic destruction and sensing of chemical and biological weapons has become an important area of focus. The specificity and high catalytic rates of biological catalysts make them appropriate for decommissioning nerve agent stockpiles, counteracting nerve agent attacks, and remediation of organophosphate spills. A number of materials have been prepared containing enzymes for the destruction of and protection against organophosphate nerve agents and biological warfare agents. This review discusses the major chemical and biological warfare agents, decontamination methods, and biomaterials that have potential for the preparation of decontamination wipes, gas filters, column packings, protective wear, and self-decontaminating paints and coatings.

Biomaterials for molecular electronics development of optical biosensor for retinol
Ramanathan, K., J. Svitel, et al. (2001), Appl Biochem Biotechnol 96(1-3): 277-91.
Abstract: Molecular electronics involves expertise from several branches of science. Various biomaterials and electronics are involved in the fabrication of such devices. While passive biomaterials are involved in anchoring the active biomolecules, the latter are involved in switching and/or signal transduction. In the present investigation we have used a glass-capillary-based approach to design a biosensor for retinol. The sensing element is retinol-binding protein (RBP). The affinity of retinoic-acid-horseradish peroxidase (conjugate) to RBP is tested using a surface plasmon resonance technique. A simple photomultiplier-tube-based system is exploited to monitor the chemiluminescent signal generated upon reaction of hydrogen peroxide and luminol with the conjugate bound to RBP. The photomultiplier tube is directly coupled to a computer for data logging.

Biomaterials for orthopedic surgery in osteoporotic bone: a comparative study in osteopenic rats
Fini, M., N. Nicoli Aldini, et al. (1997), Int J Artif Organs 20(5): 291-7.
Abstract: To evaluate orthopedic devices in pathological bone, an experimental study was performed by implanting Titanium (Ti) and Hydroxyapatite (HA) rods in normal and osteopenic bone. Twenty-four rats were used: 12 were left intact (Control: C) while the other 12 were ovariectomized (OVX). After 4 months all the animals were submitted to the implant of Ti or HA in the left femoral condyle (Ti-C, HA-C, Ti-OVX, HA-OVX). Two months later the animals were sacrificed for histomorphometric, ultrastructural and microanalytic studies. Our results show a significant difference between the Affinity Index (A.I.) of HA-C and Ti-C (77.0 +/- 7.4 vs 61.2 +/- 9.7) (p < 0.05). No significant differences were observed between the osteointegration of Ti-C and Ti-OVX (61.2 +/- 9.7 vs 48.2 +/- 6.7). Significant differences also exist between the osteointegration of HA-C and HA-OVX (77.0 +/- 7.4 vs 57.6 +/- 11.5) (p < 0.01). Microanalysis shows some modifications in Sulphur (S) concentration at the bone/biomaterial interface of the Ti-OVX group. Therefore our results confirmed the importance of biomaterials characteristics and of bone quality in osteointegration processes.

Biomaterials for pelvic floor reconstruction
Karlovsky, M. E., A. A. Thakre, et al. (2005), Urology 66(3): 469-75.

Biomaterials for primary closure of a choledochotomy in dogs
Mutter, D., M. Aprahamian, et al. (1996), Eur Surg Res 28(1): 32-8.
Abstract: Since primary closure of the common bile duct is often not undertaken because of the risks of biliary leakage and peritonitis, we have evaluated feasibility and reliability of closure using biomaterials. In three groups of dogs, an unsutured choledochotomy was closed with circular glued patches: a scleroprotein patch in 4 dogs and an oxidized, compressed human collagen patch reinforced (n = 6) or not (n = 6) with three stitches. The scleroprotein patch (n = 4) was resorbed too soon, and in 2 dogs the unstitched collagen patches became unglued; biliary leakage was the result in both instances. The bile duct healed successfully within 1 month in the other 10 animals fitted with collagen patches, despite one common bile duct stricture. Safe primary closure of a choledochotomy may be envisioned in humans if the duct suture is protected by this new collagen biomaterial.

Biomaterials for reconstruction of the cranial vault
Gosain, A. K. (2005), Plast Reconstr Surg 116(2): 663-6.

Biomaterials for reconstruction of the internal orbit
Potter, J. K. and E. Ellis (2004), J Oral Maxillofac Surg 62(10): 1280-97.

Biomaterials for rotary blood pumps
van Oeveren, W. (1995), Artif Organs 19(7): 603-7.
Abstract: Rotary blood pumps are used for cardiac assist and cardiopulmonary support since mechanical blood damage is less than with conventional roller pumps. The high shear rate in the rotary pump and the reduced anti-coagulation of the patient during prolonged pumping enforces high demands on the biocompatibility of the materials in the pump in order to prevent thrombus formation. Materials with a very hydrophobic character appear to adsorb much thrombin and induce a conformational change of fibrinogen, resulting in a surface with a high affinity for platelet interaction. Furthermore, high shear forces of 120 dyne-s-cm2 in rotary pumps induce platelet release and platelet aggregation. Thus, hydrophobic materials and high shear rates should be prevented to avoid thrombus formation in rotary blood pumps.

Biomaterials for the dental market
Cornell, J. (1988), J Biomater Appl 2(3): 346-57.
Abstract: There are a number of products and improvements in existing products desired by the dental industries. However, it is important to realize that the dental marketing system is changing and uses different criteria than those which influenced the marketing in the last decade. More integrated systems are being marketed to the dentists, and the consumers are more interested in products which will help them maintain their teeth and gums. Fluoridation and other changes have helped in retaining the teeth, usually for the whole lifetime. This progress will change the way dentists practice, and will change the materials and equipment they need.

Biomaterials for tissue engineering
Kim, B. S., C. E. Baez, et al. (2000), World J Urol 18(1): 2-9.
Abstract: Biomaterials play a critical role in the engineering of new functional genitourinary tissues for the replacement of lost or malfunctioning tissues. They provide a temporary scaffolding to guide new tissue growth and organization and may provide bioactive signals (e.g., cell-adhesion peptides and growth factors) required for the retention of tissue-specific gene expression. A variety of biomaterials, which can be classified into three types--naturally derived materials (e.g., collagen and alginate), acellular tissue matrices (e.g., bladder submucosa and small-intestinal submucosa), and synthetic polymers [e.g., polyglycolic acid, polylactic acid, and poly(lactic-co-glycolic acid)]--have proved to be useful in the reconstruction of a number of genitourinary tissues in animal models. Some of these materials are currently being used clinically for genitourinary applications. Ultimately, the development or selection of appropriate biomaterials may allow the engineering of multiple types of functional genitourinary tissues.

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