The story of Bioglass Hench, Larry L
Journal of materials science. Materials in medicine,
11/2006, Letnik:
17, Številka:
11
Journal Article
Recenzirano
Historically the function of biomaterials has been to replace diseased or damaged tissues. First generation biomaterials were selected to be as bio-inert as possible and thereby minimize formation of ...scar tissue at the interface with host tissues. Bioactive glasses were discovered in 1969 and provided for the first time an alternative; second generation, interfacial bonding of an implant with host tissues. Tissue regeneration and repair using the gene activation properties of Bioglass provide a third generation of biomaterials. This article reviews the 40 year history of the development of bioactive glasses, with emphasis on the first composition, 45S5 Bioglass, that has been in clinical use since 1985. The steps of discovery, characterization, in vivo and in vitro evaluation, clinical studies and product development are summarized along with the technology transfer processes.
During the 1960s and 1970s, a first generation of materials was specially developed for use inside the human body. These developments became the basis for the field of biomaterials. The devices made ...from biomaterials are called prostheses. Professor Bill Bonfield was one of the first to recognize the importance of understanding the mechanical properties of tissues, especially bone, in order to achieve reliable skeletal prostheses. His research was one of the pioneering efforts to understand the interaction of biomaterials with living tissues. The goal of all early biomaterials was to ‘achieve a suitable combination of physical properties to match those of the replaced tissue with a minimal toxic response in the host’. By 1980, there were more than 50 implanted prostheses in clinical use made from 40 different materials. At that time, more than three million prosthetic parts were being implanted in patients worldwide each year. A common feature of most of the 40 materials was biological ‘inertness’. Almost all materials used in the body were single-phase materials. Most implant materials were adaptations of already existing commercial materials with higher levels of purity to eliminate release of toxic by-products and minimize corrosion. This article is a tribute to Bill Bonfield's pioneering efforts in the field of bone biomechanics, biomaterials and interdisciplinary research. It is also a brief summary of the evolution of bioactive materials and the opportunities for tailoring the composition, texture and surface chemistry of them to meet five important challenges for the twenty-first century.
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The applications of bioactive glasses (BGs) have to a great extent been related to the replacement, regeneration and repair of hard tissues, such as bone and teeth, and there is an ...extensive bibliography documenting the role of BGs as bone replacement materials and in bone tissue engineering applications. Interestingly, many of the biochemical reactions arising from the contact of BGs with bodily fluids, in particular the local increase in concentration of various ions at the glass–tissue interface, are also relevant to mechanisms involved in soft tissue regeneration. An increasing number of studies report on the application of BGs in contact with soft tissues, aiming at exploiting the well-known bioactive properties of BGs in soft tissue regeneration and wound healing. This review focuses on research, sometimes involving preliminary in vitro studies but also in vivo evidence, that demonstrates the suitability of BGs in contact with tissues outside the skeletal system, which includes studies investigating vascularization, wound healing and cardiac, lung, nerve, gastrointestinal, urinary tract and laryngeal tissue repair using BGs in various forms of particulates, fibers and nanoparticles with and without polymer components. Potentially active mechanisms of interaction of BGs and soft tissues based on the surface bioreactivity of BGs and on biomechanical stimuli affecting the soft tissue–BG collagenous bonding are discussed based on results in the literature.
The future of bioactive ceramics Hench, Larry L.
Journal of materials science. Materials in medicine,
02/2015, Letnik:
26, Številka:
2
Journal Article
Recenzirano
Two important worldwide needs must be satisfied in the future; (1) treatment of the deteriorating health of an aging population and, (2) decreasing healthcare costs to meet the needs of an increased ...population. The ethical and economic dilemma is how to achieve equality in quality of care while at the same time decreasing cost of care for an ever-expanding number of people. The limited lifetime of prosthetic devices made from first-generation nearly inert biomaterials requires new approaches to meet these two large needs. This paper advises an expanded emphasis on: (1) regeneration of tissues and (2) prevention of tissue deterioration to meet this growing need. Innovative use of bioactive ceramics with genetic control of in situ tissue responses offers the potential to achieve both tissue regeneration and prevention. Clinical success of use of bioactive glass for bone regeneration is evidence that this concept works. Likewise the use of micron sized bioactive glass powders in a dentifrice for re-mineralization of teeth provides evidence that prevention of tissue deterioration is also possible. This opinion paper outlines clinical needs that could be met by innovative use of bioactive glasses and ceramics in the near future; including: regeneration of skeletal tissues that is patient specific and genetic based, load-bearing bioactive glass–ceramics for skeletal and ligament and tendon repair, repair and regeneration of soft tissues, and rapid low-cost analysis of human cell-biomaterial interactions leading to patient specific diagnoses and treatments using molecularly tailored bioceramics.
Bioactive glasses were discovered in 1969 and provided for the first time an alternative to nearly inert implant materials. Bioglass formed a rapid, strong, and stable bond with host tissues. This ...article examines the frontiers of research crossed to achieve clinical use of bioactive glasses and glass-ceramics. In the 1980s, it was discovered that bioactive glasses could be used in particulate form to stimulate osteogenesis, which thereby led to the concept of regeneration of tissues. Later, it was discovered that the dissolution ions from the glasses behaved like growth factors, providing signals to the cells. This article summarizes the frontiers of knowledge crossed during four eras of development of bioactive glasses that have led from concept of bioactivity to widespread clinical and commercial use, with emphasis on the first composition, 45S5 Bioglass(®). The four eras are (a) discovery, (b) clinical application, (c) tissue regeneration, and (d) innovation. Questions still to be answered for the fourth era are included to stimulate innovation in the field and exploration of new frontiers that can be the basis for a general theory of bioactive stimulation of regeneration of tissues and application to numerous clinical needs.
Bioceramics Hench, Larry L.
Journal of the American Ceramic Society,
July 1998, Letnik:
81, Številka:
7
Journal Article
Recenzirano
Ceramics used for the repair and reconstruction of diseased or damaged parts of the musculo‐skeletal system, termed bioceramics, may be bioinert (e.g., alumina and zirconia), resorbable (e.g., ...tricalcium phosphate), bioactive (e.g., hydroxyapatite, bioactive glasses, and glass‐ceramics), or porous for tissue ingrowth (e.g., hydroxyapatite‐coated metals). Applications include replacements for hips, knees, teeth, tendons, and ligaments and repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jaw bone, spinal fusion, and bone repair after tumor surgery. Pyrolytic carbon coatings are thromboresistant and are used for prosthetic heart valves. The mechanisms of tissue bonding to bioactive ceramics have resulted in the molecular design of bioceramics for interfacial bonding with hard and soft tissue. Bioactive composites are being developed with high toughness and elastic modulus that match with bone. Therapeutic treatment of cancer has been achieved by localized delivery of radioactive isotopes via glass beads. Clinical success of bioceramics has led to a remarkable advance in the quality of life for millions of people.
Historically the function of biomaterials was to
replace diseased or damaged tissues. First generation biomaterials
were selected to be as bio-inert as possible and
thereby minimize formation of scar ...tissue at the interface
with host tissues. Bioactive glasseswere discovered in
1969 and provided for the first time an alternative; strong,
stable interfacial bonding of an implant with host tissues.
In the 1980’s it was discovered that bioactive glasses could
be used in particulae form to stimulate osteogenesiswhich
thereby led to the concept of regeneration of tissues. This
article summarizes the four eras of development of bioactive
glasses that have led from concept of bioactivity to
widespread clinical and commercial use, with emphasis
on the first composition, 45S5 Bioglassr. The four eras
are; A) Era of Discovery, B) Era of Clinical Application,
C) Era of Tissue Regeneration, and D) Era of Innovation.
Key scientific and technological questions answered for
the first three eras are presented. Questions still to be answered
for the fourth era are included to stimulate innovation
in the field.
The aim of this study was to analyse human osteoblast responses to a porous bioactive glass scaffold. It was hypothesised that osteoblasts would attach, proliferate and form mineralised nodules in ...response to culture on the bioactive glass. As dissolution products are a key feature of bioactive glasses, this was measured by inductively coupled plasma optical emission spectroscopy to determine effects of both the glass surface and ion release. Osteoblasts attached and proliferated on the foams as demonstrated by scanning electron microscopy. Nodule formation was also observed in the pores of the glass and also in conditioned medium containing dissolution products at certain concentrations and these nodules were shown to be mineralised by alizarin red staining. Undiluted dissolution products from the foams however caused significant apoptosis suggesting an ion concentration dependent response.
A 3D scaffold has been developed that has the potential to fulfil the criteria for an ideal scaffold for bone tissue engineering. Sol–gel derived bioactive glasses of the 70S30C (70
mol% SiO
2, 30
...mol% CaO) composition have been foamed to produce 3D bioactive scaffolds with hierarchical interconnected pore morphologies similar to trabecular bone. The scaffolds consist of a hierarchical pore network with macropores in excess of 500
μm connected by pore windows with diameters in excess of 100
μm, which is thought to be the minimum pore diameter required for tissue ingrowth and vasularisation in the human body. The scaffolds also have textural porosity in the mesopore range (10–20
nm). The scaffolds were sintered at 600, 700, 800 and 1000
°C. As sintering temperature was increased to 800
°C the compressive strength increased from 0.34 to 2.26
MPa due to a thickening of the pore walls and a reduction in the textural porosity. The compressive strength is in the range of that of trabecular bone (2–12
MPa). Importantly, the modal interconnected pore diameter (98
μm) was still suitable for tissue engineering applications and bioactivity is maintained. Bioactive glass foam scaffolds sintered at 800
°C for 2
h fulfill the criteria for an ideal scaffold for tissue engineering applications.
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