Biomaterials.info - Resources for Engineers

Record 1061 to 1080

Biomaterials science and high-throughput screening
Hubbell, J. A. (2004), Nat Biotechnol 22(7): 828-9.

Biomaterials science at a crossroads: are current product liability laws in the United States hampering innovation and the development of safer medical implants?
Kohn, J. (1996), Pharm Res 13(6): 815-9.

Biomaterials science protocols for clinical investigations on porous alumina ceramic and vitreous carbon implants
Lemons, J. E. (1975), J Biomed Mater Res 9(4): 9-16.
Abstract: A written protocol for the investigation of candidate surgical implant materials is quite important. Biomaterials science sections of clinical protocols have been developed for porous alumina ceramic and nonporous vitreous carbon biomaterials. Published data on the properties of the biomaterials were evaluated as related to bone replacement and augmentation. Where necessary, limited laboratory studies were conducted. If decisions could not be reached with respect to a given application, animal studies were initiated. The surgeons worked with biomaterials in the laboratory and the biomaterials scientist attended the experimental surgery procedures. Biomaterials Science Laboratory nondestructive investigations including stereomicroscopic and x-ray inspections were conducted on the vitreous carbon dental implant systems. The investigations elucidated a number of unexpected features for both implant biomaterials and the overall interaction between the different disciplines resulted in a more complete protocol for the study of these biomaterials at our Medical and Dental Center.

Biomaterials science, medical devices, and artificial organs. Synergistic interactions for the 1990s
Schoen, F. J. (1991), ASAIO Trans 37(2): 44-8.

Biomaterials science: prospects for the new millenium?
Baquey, C. (1999), J Mater Sci Mater Med 10(12): 695-6.

Biomaterials supplement. Introductory remarks
Schaldach, M. and P. Baurschmidt (1980), Med Biol Eng Comput 18(4): 493-5.

Biomaterials to prevent nosocomial infections: is silver the gold standard?
Stickler, D. J. (2000), Curr Opin Infect Dis 13(4): 389-393.
Abstract: Although many antimicrobial biomaterials have shown promising activity in vitro, few anti-infective prosthetic devices manufactured from these materials have yet achieved any degree of success in clinical trials. Controversy surrounds the exploitation of antibiotics in these materials and the microbiological methods that have been used in the clinical trials on the devices.

Biomaterials unavailability threatens medical devices
Citron, P. and K. Stokes (1997), Pacing Clin Electrophysiol 20(7): 1863-5.

Biomaterials used in injectable implants (liquid embolics) for percutaneous filling of vascular spaces
Jordan, O., E. Doelker, et al. (2005), Cardiovasc Intervent Radiol 28(5): 561-9.
Abstract: The biomaterials currently used in injectable implants (liquid embolics) for minimally invasive image-guided treatment of vascular lesions undergo, once injected in situ, a phase transition based on a variety of physicochemical principles. The mechanisms leading to the formation of a solid implant include polymerization, precipitation and cross-linking through ionic or thermal process. The biomaterial characteristics have to meet the requirements of a variety of treatment conditions. The viscosity of the liquid is adapted to the access instrument, which can range from 0.2 mm to 3 mm in diameter and from a few centimeters up to 200 cm in length. Once such liquid embolics reach the vascular space, they are designed to become occlusive by inducing thrombosis or directly blocking the lesion when hardening of the embolics occurs. The safe delivery of such implants critically depends on their visibility and their hardening mechanism. Once delivered, the safety and effectiveness issues are related to implant functions such as biocompatibility, biodegradability or biomechanical properties. We review here the available and the experimental products with respect to the nature of the polymer, the mechanism of gel cast formation and the key characteristics that govern the choice of effective injectable implants.

Biomaterials used in the posterior segment of the eye
Colthurst, M. J., R. L. Williams, et al. (2000), Biomaterials 21(7): 649-65.
Abstract: The treatment of posterior segment eye disease and related conditions has improved greatly in recent years with the advent of new therapies, materials and devices. Vitreoretinal conditions, however, remain significant causes of blindness in the developed world. Biomaterials play a major role in the treatment of many of these disorders and the success rate of vitreoretinal surgery, especially in the repair of retinal detachment and related conditions, would increase with the introduction of new and improved materials. This review, which focuses on disorders that feature retinal detachment, briefly describes the anatomy of the eye and the nature and treatment of posterior segment eye disorders. The roles, required properties and suitability of the materials used in vitreoretinal surgery as scleral buckles, tamponade agents or drug delivery devices, are reviewed. Experimental approaches are discussed, along with the methods used for their evaluation, and future directions for biomaterial research in the posterior segment of the eye are considered.

Biomaterials used in urology: current issues of biocompatibility, infection, and encrustation
Denstedt, J. D., T. A. Wollin, et al. (1998), J Endourol 12(6): 493-500.
Abstract: This review focuses on the biomaterials used in urology, in particular, the properties of urethral catheters and ureteral stents currently being used in clinical practice. The importance of biomaterial type, biocompatibility, and encrustations are discussed and explained. Current management of bacterial infection and the importance of biofilms are presented, with recommendations based on published information.

Biomaterials with hierarchically defined micro- and nanoscale structure
Tan, J. and W. M. Saltzman (2004), Biomaterials 25(17): 3593-601.
Abstract: Biomaterials and tissue engineering are becoming increasingly important in biomedical practice, particularly as the population ages. It is clear that cellular responses to materials depend on structural properties of the material at both the micrometer- and nanometer scale, but general methods for controlling material properties on both of these scales are lacking. Using a hierarchical approach that mimics natural material formation processes, we developed a method to produce materials with controlled physical structures at both the micrometer- and nanometer scale. Our method is based upon a pre-organized micropatterned template and conformal transformation of the architecture with nanostructured minerals, namely hydroxyapatite. The newly developed materials were biocompatible with bone cells, induced a range of desirable cellular responses, and may therefore have direct application in bone tissue engineering. In addition, the design principles employed in this study can be extrapolated to the other classes of biomedical materials, including polymers, metals, ceramics or hybrid combinations.

Biomaterials with permanent hydrophilic surfaces and low protein adsorption properties
Rabinow, B. E., Y. S. Ding, et al. (1994), J Biomater Sci Polym Ed 6(1): 91-109.
Abstract: Low protein adsorbing polymer films have been prepared with which to fabricate intravenous containers, designed for compatibility with low concentrations of protein drugs. The material is economically manufactured utilizing physical melt blending of water-soluble surface-modifying polymers (PEO, PEOX, PVA, and PNVP) with a base polymer (EVA, PP, PETG, PMMA, SB, and nylon). Permanency of the hydrophilic surfaces so generated was confirmed by surface contact angle experiments and total organic carbon leachables analysis of the aqueous contacting solutions. Binding of IgG, albumin and insulin was studied. A sixfold reduction of protein adsorption was obtained by adding 5% PVA13K to EVA, for IgG at a bulk concentration of 2.5 ppm. Surface bound protein measured by micro-BCA colorimetry, agreed with the solution protein lost, as determined by the Fluoraldehyde procedure. Imaging of the protein exposed plastic surfaces by silver enhanced protein conjugated gold staining agreed with the quantitative assay determinations.

Biomaterials, biocompatibility, and peri-implant considerations
Lemons, J. and J. Natiella (1986), Dent Clin North Am 30(1): 3-23.
Abstract: There are series of tests recommended for evaluation of dental implants. These materials and instrumentation coupled with the publications reviewed here that deal with animal experimentation and implant experience in humans provide an outline of data that have made tissue response to dental implants more clearly delineated. However, there are several specific aspects of cellular response that remain to be illuminated and correlated with clinical and radiographic signs. The further study of the interface zone with corresponding characterization of materials will produce the final chapter in the development of this most interesting area of dentistry. As stated, no epithelial attachment to any dental implant post has been comprehensively described that utilizes light and electron microscopy or histochemistry. Rather, a concept of a biologic seal has emerged that delineates the external milieu of the mouth with its microbiota and plaque from the internal milieu of bone and connective tissue, where true osseointegration can and does take place.

Biomaterials, biomechanics, tissue healing, and immediate-function dental implants
Lemons, J. E. (2004), J Oral Implantol 30(5): 318-24.
Abstract: Selected factors and opinions are reviewed specific to immediate function of dental implants in terms of biomaterial and biomechanical properties and how they might influence postsurgical tissue healing. Comparisons are made among plate, rod, and screw vs plateau, finn, and porous geometry endosteal dental-implant designs with and without alterations in device body-surface microchemistry and microtopography. Available information introduces more questions than answers, and recommendations are made for ongoing studies of bone responses specific to the implant fit and fill parameters focused on the kinetics of postsurgical osteotomy healing and applied loading. The clinical literature supports opportunities for immediate function; however, proposals about pathways for bone healing need further investigation. The current trends within the discipline of implant dentistry offer opportunities to reevaluate current vs previous immediate-function systems.

Biomaterials, scar tissue and ophthalmic microsurgery
Constable, I. J. (1989), Aust N Z J Surg 59(10): 755-9.

Biomaterials. New Chinese biochip center straddles business, academe
Yimin, D. (2000), Science 290(5499): 2061-2.

Biomaterials. Reverse engineering the ceramic art of algae
Amato, I. (1999), Science 286(5442): 1059, 1061.

Biomaterials: a forecast for the future
Hench, L. L. (1998), Biomaterials 19(16): 1419-23.
Abstract: The survivability half-life of prostheses made with current bio-inert materials is approximately 15 years, depending upon clinical applications. Bioactive materials improve device lifetime but have mechanical limitations. This paper proposes that biomaterials research needs to focus on regeneration of tissues instead of replacement. Alternatives are: use hierarchical bioactive scaffolds to engineer in vitro living cellular constructs for transplantation, or use resorbable bioactive particulates or porous networks to activate in vivo the mechanisms of tissue regeneration.

Biomaterials: an overview
Valiathan, M. S. and V. K. Krishnan (1999), Natl Med J India 12(6): 270-4.

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