Preparation And Properties Research Of Thermosensitive Bone Cement Hydrogels

Now clinically the nμmber of patients who need hip replacement surgery are becoming more and more due to femoral head necrosis,and with China’s rapidly aging society,the operation demand will continue to increase substantially.Currently,hip replacements of bone cement and bone cementless type are adopted to treat this kind of disease in clinical.The bone cement can timely fix prosthesis to recover walking from the disease as soon as possible.But after surgery,serious bone cement syndrome occurred because the bone cement was pressurized into the marrow cavity in the process of surgery,which led to a serious threat to patient safety.In addition,bone cement synthesis process will release a lot of heat,causing high local temperature to damage cells and tissues.The biological immobilization cannot be achieved because there was unable to form a biological connection among bone-bone cement-prosthesis,eventually leading to prosthesis loosening to cause the question of the postoperative overhaul.These problems restricted the clinical application of bone cement.Therefore it is urgent to solve the clinical problems.The proportion of bone cementless hip arthroplasty has drastically increased in the clinical application,which alleviated syndrome of bone cement to some extent.But the serious postoperative overhaul problem still existed.Thus if these clinical problems can be solved completely,it will ease the pain of patients,reduce the burden of patients,which brings significant clinical value and academic significance to the research.Aiming at clinical problems of artificial hip replacement,this topic plans to develop a kind of gel material used in the hip replacement surgery instead of bone cement.On the one hand,the material has short-time solidification characteristics in the body,and syndrome of bone cement is expected to avoid because of without pressurization in the operation,on the another hand,the material has the function of bone tissue engineering and can attract bone cells to grow into bone cement to finish biological connection,realizing the biological immobilization,which improves the effect of an operation of long-term treatment,and reduces or eliminates postoperative overhaul problem.This study firstly used the bionic method to deposite hydroxyapatite(HAP)to micron grade silk protein to prepare silk fibroin/hydroxyapatite(SF/HAP)composite of which the structure is like collagen /hydroxyapatite structure of natural bone and which is an active ingredient induced bone growth.And then the chitosan(CS)and glycerin sodium phosphate(GP)was selected as a basic thermosensitive hydrogel system.The mechanical properties of the gel material were improved by adding polyvinyl alcohol(PVA)andgenipin.SF/HAP composite,as an active ingredient induced bone growth,was added to attract bone cells to grow into the system,which improved bone compatibility of gel materials.Finally the gel material possessing thermosensitive and inducing bone growth functions was prepared and was carried out the preliminary evaluation to its structure and properties.The paper used FIRT、XRD and SEM to determine the structure of SF/HAP;adopting FIRT 、 SEM 、 soaking liquid method and rheological method analyzed the internal structure of the materials,physical properties,rheological properties and mechanical properties;adopting simulating artificial fluid method studyed the degradation properties of the gel material in vitro;MTT and SEM methods is used to study the cell compatibility of materials;the blood compatibility of the materials was tested by hemolysis test,dynamic coagulation test and platelet adhesion test.The result of FIRT,XRD and SEM showed that HAP had deposited on the SF,and SF/HAP is similar to structure of natural bone.Four groups of the optimal gel material were screened by screening standard-gel time and gel time was immensely reduced with the increase of temperature.FIRT and SEM determined the SF/HAP was introduced into the material,the surface is smooth,and internal hole aperture is 50-200 μm.Porosity of materials was about 25%;the moisture content was about 85%,and it has a good swelling rate.Rheological properties showed that the existence of the internal network structure in gel materials and excellent material distortion resistance.Degradation experiment result showed that the degradation rate of four weeks was about 50%;material surface gradually collapse and the number and the diameter of internal hole became more and larger as the time of degradation was prolonged.Cell experiment results showed that the gel material had no cytotoxicity to L929 cell and human osteoblasts(H0-F),and HO-F cells could adhere and grow on the surface of gel materials.Platelet adhesion rate and hemolysis rate of material all met the national standards,and the materials had excellent anticoagulation capability,which showed that the material had good blood compatibility.Research shows that the material can be relatively rapid solidification,has better mechanical properties,and can support adhesion and growth of osteoblast.Thus,it is a promising bone cement gel materials to be applied in hip replacement surgery.