| abstract |
Present invention depicts a poly-porous (micropore) hollow screws as diffusion chamber filled with core matrix for targeted delivery of growth factors and bone marrow stem cells. The screws comprise at least two parts: the distal part of the screw consists of the tip of the screw made of poly porous material and hollow inside proximally. It has threaded navel attached to the threaded nipple of the distal part of the proximal screw which has the screw head and is made of the solid material of the same kind. The screw head had hexagonal recess targeted for screw driver insertion. Assembly of screw created a chamber in the middle of the screw. The chamber is filled with core matrix consisting of gelatin nano-particles pre-impregnated with BMPs (BMP2/BMP7 for bone or BMP12 for tendon, ligament) and fibrin sealants or Chitosan dispersed with bone marrow stem cells and/or other growth factors. Bioactive protein core material is prepared during the surgery and filled the chamber of the screw by the surgeon. Fibrin sealants or Chitosan will polymerize to form a gel to hold the growth factors and stem cell in place. The screw can be used as the lag screw or other function to provide mechanical fixation in variety of condition. Once the screw implanted in the human body, the fibrin sealant or Chitosin/gelatin nano-particles are gradually degraded and slowly release growth factors and stem cells via micropores of screw to facilitate the bone healing and regeneration. The gelatin nanoparticles and fibril sealant/or Chitosan matrix also serve as the scaffold and platform for bone in-growth to the screw or alternatively, the stem cell inside of screw can regenerate new bone, providing the biological fixation. At the mean time as the bone regenerate and/or in growth, mechanical strength of the screw increased. |