Originally biomaterials were used to replace diseased or damaged tissues. First generation biomaterials were selected to be as bio-inert as possible and thereby minimise interactions\u00a0at the interface with host tissues. Bioactive glasses (BGs) were discovered in 1969 and provided the interfacial bonding of an implant with host tissues as an alternative to eliminate the formation of scar tissue.1<\/p>\n
BGs can be used as a material that forms a direct bond to bone. As a result, BGs are being increasingly considered in the tissue engineering field, being investigated not only in bone tissue engineering but also in soft tissue regeneration approaches.2 BGs are able to enhance vascularization via the action of ionic dissolution products (biologically active ions), and therefore, are able to play a part in soft tissue repair (such as wound healing).<\/p>\n
Meet Professor Aldo R Boccaccini \u2013 professor of Biomaterials and Head of the Institute of Biomaterials at the Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Germany. Boccaccini\u2019s main research area is the use of glasses, ceramics and polymer\/glass composites for biomedical, functional, and structural applications.<\/p>\n
Innovation News Network speaks with Boccaccini to talk about his current project \u2018Bioactive glasses: from bone regeneration to wound healing\u2019, and how BGs are breaking into the world of wound healing.<\/p>\n
BGs are a family of inorganic materials based on silicate, phosphate and borate compositions.\u00a0 Most extensively investigated BGs are in the silicate system, especially as bone substituting materials and in bone tissue engineering. On the other hand borate BGs are being increasingly\u00a0 considered in wound healing applications. BGs are important because they were the first man made material that was shown to connect\/bond directly to bone. Originally bioactive glass was developed as a substitute material for bone; a material that would create a very strong link\/bond with bone tissue, and therefore would be used as an alternative to other materials, for example in bone replacement devices, dental applications, small bone implants and coatings.<\/p>\n
Later on research found that when BGs were in contact with bodily fluids, they would release particular ions, dissolution as products, and these ions released from the bio glass are also active and interact with the cells \u2013 they are biologically active ions. This is also really important because you don\u2019t only have this initial effect of direct bonding with bone tissue, but you also have direct\u00a0biological effects on cells induced by the release of specific concentrations of these metallic ions from the glass.<\/p>\n
Originally, the interest in BGs stemmed from their use as a substitute material (for example in bone replacement devices, bone filling materials or dental applications). This interest then started to go towards tissue regeneration and soft-tissue engineering, where these glasses are being proposed in particular applications related to a variety of tissues in the human body. One of which is wound healing.<\/p>\n
The research here is trying to understand how the BGs can promote the healing of wounds and burns. For example, one particular case is difficult-to-heal wounds such as diabetic wounds \u2013 people who suffer diabetes can develop incurable wounds in their legs, in some cases such chronic wounds are so tragic, for example due to high risk of infections, that the leg must be amputated. BGs in different shapes, for example fibers or particulate in composites, can be positively used to heal these wounds, especially by using the release of ions which will have an angiogenic and anti-bacterial effect. Some products based on BGs for wound healing are already available. The glasses can be also designed to release specific ions that kill bacteria, and as a result, stop the spread of infections in the site of the wound.<\/p>\n
What we are doing in our research projects, for example, is adding bioactive glass particles into polymeric fibres (which we fabricate through electrospinning), and these composite fibres will act as a flexible, porous, wound-dressing material that can be effective in the treatment of chronic wounds by releasing biologically active ions in controlled temporal and spatial manner from the BG particles during the degradation of the fibers.<\/p>\n
In general, the challenge is to be able to characterise the effect of BGs in relevant in vivo situations (in a real body environment). However, many research studies have focused on in vitro (cell biology) studies (outside if the body). One challenge would therefore be to expand the number of in vivo studies, both in bone regeneration, and soft tissue regeneration and wound healing. To overcome this challenge, it would require us to better understand the behaviour of the material during the time of implantation into the in vivo environment on a well-designed animal model.<\/p>\n
Within this project, we are continuing to enhance the capability of these materials by investigating the effects of different chemical compositions. Our work and the work of numerous research groups worldwide investigating BGs is contributing to develop a library of chemical compositions of different BGs, and we are particularly interested in understanding what is the combined or synergistic effect of different ions, in different concentrations, on different types of cells relevant to the mechanisms of tissue regeneration and wound healing. We think that by increasing the complexity of the chemical composition of the glasses, by adding different ions that are going to be released under different time-dependent concentration ratios, we will be able to provide better or more effective healing effects.<\/p>\n
The future and the hope of BGs in my opinion, is that they become materials of choice to tackle many of the current unmet medical needs, for example, in the areas of chronic wound healing, antibiotic-free treatment of bone infections and even in some cases, in terms of treating cancer. This is because it has been previously shown that BGs of specific morphologies (for example nanoparticles or mesoporous structures) can act as drug carriers and could be designed to synergistically connect the direct and controlled delivery of drugs for cancer treatment with, for example, the effect of biologically active ions released from the carrier (bioactive glass).<\/p>\n
Aldo R Boccaccini<\/p>\n
Head of the Institute of Biomaterials<\/p>\n
Department of Materials Science and Engineering<\/p>\n
University of Erlangen-Nuremberg<\/p>\n
+49 91318528601<\/p>\n
aldo.boccaccini@fau.de<\/p>\n