Bone tissue engineering represents one of the most challenging emergent scientific and clinical fields. Although bone tissue naturally regenerates, its self-healing potential is restricted to relatively small fractures. Large bone defects usually require intervention in the form of reconstruction and when caused by trauma, infection or skeletal diseases, bone grafting is necessary to repair or improve the function of injured bone. The healing process of large bone defects requires the combination of the following processes:
  - Osteogenesis – Osteoprogenitor cells differentiating into bone-forming cells
  - Osteoinduction – Signals and growth factors which stimulate bone cells' differentiation and propagation
  - Osteoconduction – A matrix, or scaffold, acting as a support surface which promotes the growth and differentiation of newly generated bone cells Current solutions for bone reconstruction include:

Sample title

Autologous bone grafts - The "gold standard" - a procedure where bone is relocated from one organ to another in the patient's body. Autologous bone grafting currently accounts for about 40% of all bone reconstruction procedures. 
Limitations:
   - An invasive surgical procedure
   - Donor site morbidity
   - Insufficient graft volume
   - Poor graft quality

Allogeneic/xenogenic bone grafts - These grafts are obtained from human cadavers, living donors or animal sources. DBM (Demineralized Bone Matrix) is employed which is produced by partial dissolution of bone tissue and consequent gain of vital organic ingredients that support bone cells. 
Limitations:
   - Suitable for small bone defects
   - Inferior bone properties
   - Risk of infection
   - Long recovery

Biosynthetic substitutes - synthetic or natural biomaterials that promote bone regeneration. 
Limitations:
   - Inferior bone properties
   - Suitable for small bone defects
   - Long recovery

Growth factors / bioactive proteins – These normally regulate cellular bone activity and induce bone regeneration. Examples include BMP, TGF-β, IGF, PDGF, FGF. 
Limitations:
 - Inferior bone properties 
 - Suitable for small bone defects 
 - Long recovery


The ideal bone graft substitute must demonstrate biocompatibility, functional and structural similarity to the defective or deficient bone, ease of use and cost-effectiveness.  
Bone tissue engineering has been developed as a promising alternative to bone grafting and as a solution exhibiting the three required processes of bone healing: osteogenesis, osteoinduction and osteoconduction. 
Current limitations
Identification of the ideal cell population for transplantation 
Inefficient procedures for cell isolation 
Expansion on the scaffold 
Preparation for grafting 

To address the limitations of existing bone regeneration therapies, Bonus BioGroup developed a unique method to grow three dimensional (3D), high-density, multi-cell bone grafts - BonoFillTM . These grafts are produced from patients' adipose (fat) tissue-derived cells, are designed to precisely fit the patients' deficient anatomical sites, and feature all ideal bone graft characteristics.