Essay On Scaffolds

Osteoporosis is translated from the Greek and literally means “porous bone “ .It is the most common chronic, metabolic bone disease in the U.S.A, resulting in osteopenia and fractures in spine , hip and wrist. In addition osteoporosis is progressive, and the skeletal fragility often leads to disabling fractures (hip fractures) and even death. Primary osteoporosis is a result of aging, whereas secondary osteoporosis occurs at any age, is a consequence to certain medication as well as diseases.

There are 206 bones in the human body. Broken and fractured bones are one of the most common injuries, about 6 million people in the US will break a bone each year. And out of these 300,000 people will have a serious injury that will require different methods to heal. There are a variety ways of bone tissue repairing but most of them are not long term and can cause other complications. There are different stages for bone repair. The first step is the formation of hematoma at the break, then the formation of a fibrocartilaginous callus, the third step is the formation of a bony callus, and finally remodeling and addition of compact bone. In the early stages, a hematoma develops within the fracture location during the first few hours and days.

After that, fracture callus will undergo the process of bone subtitution, followed with endochondral ossification, resulting in production of lamellar bone. Final remodelling of the bone is completed by deposition of compact bone by osteoblasts in resorption pits prepared by the osteoclasts (Gaston and Simpson, 2007). This natural osteonal healing would be done well if and only if these four prerequisites are active.

Different types of osteobiologic materials include: metal-based, ceramic-based and polymer-based bone graft substitutes either with or without various types of cells. Some of these materials may have various bioactive molecules such as growth factors embedded in them [47], [48-52] for example: BMP-2 [53-55], TGF-b [54], GDF-5 [56, 57] and VEGF [58] or a mixture [57], since these growth factors are among of the multiple factors expressed during bone regeneration [59-61]. Such materials have been investigated widely in literature[62], [63] to exhibit specific responses. Calcium phosphate showed osteoinductive and osteoconductive properties in the form of sintered ceramics [64-67], cements [68, 69], and coatings [70, 71]. Besides calcium phosphate

Dr Yinghong Zhou, a Postdoctoral fellow at IHBI, winning five awards last year alone, including the “Peter Doherty Australian biomedical-fellowship”. Formerly a Dentist with a keen interest in regeneration/repair, Yinghong joined the bone group in 2010. Highly experienced in surgery with rodents, offering pivotal training for this project, with major interests in

Unlike engineering material, healthy bone can maintain its reliability by restoring the micro damage and remodeling itself. Bone remodeling follows two steps handled by the cells named osteoclast and osteoblast. Osteoclasts which digests the bone at a molecular level are responsible for the bone resorption. On the other hand, new bone is formed by a group of osteoblasts cell by cell. This process results bone to preserve itself and adjust to the person’s daily activity. Although bone maintains itself, the material property is changing with the remodeling process resulting bone to gain its unique heterogeneous material distribution. Furthermore, the remodeling process, not only involve with material properties, but architecture, besides. This transformation of bone occurs as a response to altered loading conditions. The transformation can be seen in osteon density, porosity, average osteonal area etc.

Every time I learn about new theories, approaches and developments in pharmaceutical science, such as “The application of layered double hydroxide clay (LDH)-poly (lactide-co-glycolic acid) (PLGA) film composites for the controlled release of antibiotics.” (Journal of Materials Science: Materials in Medicine Volume 23, Issue 7, pp 1705-1713), I cannot help feeling excited.

The polymer that I choose is polyethylene glycol (PEG). Polyethylene glycol is produced because of the interaction with ethylene oxide with water, ethylene glycol or ethylene glycol oligomers. Some cons of using polyethylene glycol are hypersensitivity, unexpected change in pharmacokinetic behavior, and toxic side products. PEG is also a laxative that can also be used to prepare the bowels before surgery. PEG is also used to slow the clearing of protein from the blood. This makes medicine last longer in the body. Polyethylene glycol has also been used to help the healing of the spine inn dogs and PEG can also help with nerve damage. PEG is most commonly used with the skin because it has maintains it shape well, it is also pliable so doctors can put it in place before setting it with a green LED light.

Tissue transplantation is the second-most common procedure after blood with over 2.2 million bone graft procedures conducted worldwide annually in the realms of orthopedics and dentistry. Surgical reconstruction, transplantation (autografts and allografts), drug therapy, artificial prostheses and medical devices are the current clinical treatment options for various tissue related disorders including bone tissue [63]. These treatment options have disadvantages such as severe pain, risk of infections, hematoma, immune rejection, donor site morbidity, transmission of viral (HIV, hepatitis-B) and prion proteins [64=135]. However, relatively few orthopedic biomaterials designed with bio-responsive characteristics have been translated into clinical

Nowadays, bone repair and regeneration has become a popular issue that many scientists use varies method to attempt to solve this problem. Several papers mentioned that scientists tried to solve this problem by either using autograft or allograft bone tissues. Due to the limitations of autografting such as patient pain, donor site morbidity, and limited supply, allografting has been used as alternative. Before using allografting, the understanding of its compatibility, possible transmission of diseases, and immune reaction is quite important. Hence, the scaffolds need to be consider in many aspect because as a critical role for cell growth and attachment while providing a temporary support for the damage sites. Besides biopolymer, several inorganic materials such as metals or ceramics are widely used in bone tissue engineering recently to constitute the bone scaffolds.

Regeneration has been defined as the reproduction or reconstitution of a lost or injured part to restore the architecture and function of the periodontium. To be considered a regenerative modality, a material or technique must histologically demonstrate that bone, cementum and a functional periodontal ligament (a new attachment apparatus) can be formed on a previously diseased root surface. Bone grafts and their synthetic substitutes have been used in an attempt to gain this therapeutic endpoint. However, among the graft materials to date, only autogenous bone of extraoral or intraoral sources and demineralized freeze dried bone allograft have human histological evidence to include them as regenerative materials. More recently the use of recombinant human bone morphogenetic proteins (BMP)-2 (Ishikawa et al. 1994), enamel matrix derivative (EMD) (Sculean et al. 1999), platelet-rich plasma (PRP) (Anitua et al. 2004), growth factors like platelet-derived growth factor (PDGF) and insulin-like growth factor-1 (IGF-1) (Lynch et al. 1989) and recombinant human basic fibroblast growth factor (bFGF) (Murakami et al. 2003) have been proposed as a source for periodontal regeneration. Initial investigation has demonstrated that anorganic bovine bone matrix supports the attachment and proliferation of osteoblastic cells in vitro (Stephan et al. 1999). Indeed, human histologic studies have concluded that this bone substitute is osteoconductive and incorporated in new bone

On the first day of the experiment, two different hydrogels were created. The first, 5 mL of a 10% weight-by-weight (w/w) Polyallylamine (PAA) solution was added in water. A single 325 mg aspirin tablet was crushed as added to the PAA solution. Next, using a syringe filter, the filler material was filtered out. The PAA solution was poured into two different 10 mL scintillation vials, with 2 ml of solution already in each.

An approach to optimize bone fusion rate is to consider FDA approved bioactive fibroin with adequate temporal control characteristics as screws for implant. [5, 6]. However, only a handful of polymeric bio-materials are utilized today because of their failure to address critical issues like compressive strength for load-bearing bone grafts. Metallic fixation systems are currently the gold standard for fracture fixation but have problems including stress shielding, palpability and temperature sensitivity. Extensive research demonstrated that silk microfiber-protein composite matrices mimicked the mechanical features of native bone including matrix stiffness and surface roughness that enhanced human mesenchymal stem cell differentiation. Administering effective growth factors to specific sites in the silk scaffold would ensure osteoblast differentiation and cell growth. Animal models have become the corner stone of research in the hope to illicit its etiology, and thus redefine the state of the art, current concepts and future perspective of possible treatments for scoliosis [1–3]. To date, many hypotheses have been put forward and studied to establish its pathogenesis. These range from neurologic cause, to genetic mutation, to morphometric alteration leading to disadvantageous biomechanical imbalances through to a probable multifactorial spinal developmental disorder. The objective of this study is determine the

Development of scaffolds plays a vital role in bone tissue engineering in order to repair, regenerate tissues by mimicking of natural bone extracellular matrixes. Considering that bone is a composite of minerals and proteins, it is preferred to develop a composite that mimics natural bone. The ideal nanocomposite materials should have biocompatibility, suitable mechanical and antimicrobial properties, nontoxicity and surface functionality to favor cell proliferation.1,2

Polymer drug conjugates as the name would suggest, are systems where drug molecules are chemically conjugated onto long chain polymers via covalent linkages. At the moment there over fourteen polymer-drug conjugates that have made it through the rigorous clinical evaluation, these are based on polyglutamic acid (PGA)-paclitaxel conjugates (CT-2303, OPAXIO®, initially known as Xyotax®) (Greco and Vicent 2009).