순환석회화전처리에 의해 인산칼슘을 코팅한 Mg mesh의 골재생능 평가 = Evaluation of bone regeneration ability of Mg mesh coated with calcium phosphate by cyclic precalcification treatment

다국어 초록 (Multilingual Abstract)

Surface treatment was conducted to reduce dissolution of Mg mesh and to improve bioactivity in physiological environment. Mg mesh was immersed in 40 wt% hydrofluoric (HF) solution for 2 hours to form a protective coating layer. Then, hydrothermal treatment was performed in a mixed solution of Ca(NO3)2·4H2O and Na2HPO4 at 90 ℃ for 30 minutes, and cyclic precalcification treatment was conducted by soaking in each 0.06 M NH4H2PO4 solution and 0.011 M Ca(OH)2 solution in turn at 90 ℃. Immersion test was performed in simulated body fluid (SBF) to investigate solubility and bioactivity. Release characteristics were investigated after loading ibandronate to suppress initial bone resorption. Bone regeneration ability was evaluated through micro-CT analysis and conforming inflammatory cytokines levels in blood. Fine granular calcium phosphate-based materials were precipitated as clusters on the surface treated in cyclic precalcification. Agglomerated calcium phosphate precipitates on the surface were observed after SBF immersion. pH in SBF during immersion increased slowly in hydrothermal treatment and cyclic precalcification groups compared to pure Mg group. Release of ibandronate occurred over 6 days in cyclic precalcification treatment group (CP-H1). IL-1β and IL-6 were significantly lower than those of untreated group in all test groups except for the group (CP-H4) that was heat-treated at 400 ℃ after pretreatment with circulating calcification. As a result of micro-CT analysis, the new bone volume and density were significantly higher in the CP-H1 group. It was concluded that cyclic precalcification treatment after formation of fluorine protective layer on Mg mesh could retard the dissolution and enhanced bone regeneration ability.

국문 초록 (Abstract)

본 연구는 생체환경에서 Mg 메쉬의 용해 억제 및 생체활성도 개선을 위해 시행되었다. 생체환경에서 Mg 메쉬의 용해를 억제하기 위해 40 wt% HF 수용액에 2시간 동안 침지하여 보호 코팅층을 형성하였다. 이후 Mg 메쉬에 생체활성을 부여하기 위해 90 ℃ Ca(NO3)2·4H2O와 Na2HPO4 혼합 수용액에 30분 동안 침지하는 수열처리 및 90 ℃에서 유지되는0.06 M NH4H2PO4 수용액과 0.011 M Ca(OH)2 수용액에서 20회 순환 석회화전처리를 한 다음 100 ℃와 400 ℃에서 열처리를 하였다. 이후 표면층 원소의 동정을 파악하기 위해 X-선 회절분석을 시행하였고, 또한 생체환경에서 용해도 및 생체활성도를 조사하기 위해 SBF 침지시험을 실시하였다. 또한 임플란트 식립부에서 일어나는 초기의 골흡수를 억제하기 위해 이반드로네이트를 탑재한 다음 방출 특성을 조사하였다. 또한 Mg 메쉬의 매식이 생체에 미치는 영향 및 골재생능에 미치는 영향을 평가하기 위해 시험쥐의 두부에 결손부를 형성하고 Mg 메쉬를 4주 동안 매식한 다음 혈중의 염증성 사이토카인의 변화 및 신생골의 부피와 밀도를 조사하였다. 이상의 시험을 통해 다음과 같은 결론을 얻었다.
1. 수열처리한 표면에서는 침상의 인산칼슘이 석출되었지만 순환 석회화전처리한 표면에는 미세한 과립상의 인산칼슘이 클러스터 상으로 석출이 되었으며, SBF 침지 후 HA 석출의 초기단계에서 관찰되는 돌기상이 석출되어 생체활성도가 개선된 결과를 보였다.
2. 37 ℃ SBF 10 mL에 7일 동안 침지했을 때의 pH 변화는 수열처리와 순환 석회화전처리 후 순수 Mg에 비해 크게 감소되었다.
3. 이반드로네이트의 탑재 처리 시, 순환 석회화전처리 후 100 ℃에서 열처리한 그룹(CP-H1)에서 6일 동안에 걸친 방출을 보였다.
4. 혈중 IL-1β와 IL-6는 순환 석회화전처리 후 400 ℃에서 열처리한 그룹(CP-H4)를 제외하고는 모든 시험 그룹에서 무처리 대조 그룹에 비해 유의하게 낮게 나타났다(P<0.05).
5. micro-CT 분석 결과, 신생골의 부피와 밀도는 순환 석회화전처리 후 100 ℃에서 열처리한 그룹(CP-H1)에서 통계학적 으로 유의하게 높게 나타났다.
이상의 결과로 미루어볼 때, 생체환경에서 Mg 메쉬의 용해 억제 및 생체활성도의 개선을 위해서 불소 보호피막층을 형성하고 순환 석회화전처리를 하여 인산칼슘을 석출하는 것은 골재생 유도의 유용한 수단이 될 수 있을 것으로 생각된다.

참고문헌 (Reference)

1 안중현, "자극감응성 PHEMA 하이브리드 젤의 제조와 팽윤거동" 한국고분자학회 35 (35): 94-98, 2011

2 Meraw SJ, "Use of alendronate in peri-implant defect regeneration" 70 (70): 151-158, 1999

3 Nguyen TDT, "The effect of APH treatment on surface bonding and osseointegration of Ti-6Al-7Nb implants : An in vitro and in vivo study" 103 (103): 641-648, 2015

4 Vercruysse KP, "Synthesis and in vitro degradation of new polyvalent hydrazide cross-linked hydrogels of hyaluronic acid" 8 (8): 686-694, 1997

5 Kim SJ, "Synthesis and characteristics of semi-interpenetrating polymer network hydrogels based on chitosan and poly(hydroxy ethyl methacrylate)" 96 (96): 86-92, 2005

6 Hanawa T, "Structure of surface-modified layers of calcium-ion-implanted Ti–6Al–4V and Ti–56Ni" 36 (36): 438-444, 1995

7 Kokubo T, "Spontaneous formation of bonelike apatite layer on chemically treated titanium metals" 79 (79): 1127-1129, 1996

8 Meraw SJ, "Qualitative analysis of peripheral peri-implant bone and influence of alendronate sodium on early bone regeneration" 70 (70): 1228-1233, 1999

9 Lo JC, "Prevalence of osteonecrosis of the jaw in patients with oral bisphosphonate exposure" 68 (68): 243-253, 2010

10 Su Y, "Preparation and corrosion behaviors of calcium phosphate conversion coating on magnesium alloy" 307 : 99-108, 2016

11 Chiappetta DA, "Poly(ethylene oxide)–poly(propylene oxide)block copolymer micelles as drug delivery agents : improved hydrosolubility, stability and bioavailability of drugs" 66 (66): 303-317, 2007

12 Tan A, "Multilayer sol–gel coatings for corrosion protection of magnesium" 198 (198): 478-482, 2005

13 Lim F, "Microencapsulated islets as bioartificial endocrine pancreas" 210 (210): 908-910, 1980

14 Staiger MP, "Magnesium and its alloys as orthopedic biomaterials : a review" 27 (27): 1728-1734, 2006

15 Peng K, "Light controlled protein release from a supramolecular hydrogel" 46 (46): 4094-4096, 2010

16 Ellingsen JE, "Improved retention and bone-to-implant contact with fluoride-modified titanium implants" 19 (19): 2004

17 Drury JL, "Hydrogels for tissue engineering : scaffold design variables and applications" 24 (24): 4337-4351, 2003

18 Tian W, "Hyaluronic acid hydrogel as Nogo-66 receptor antibody delivery system for the repairing of injured rat brain : in vitro" 102 (102): 13-22, 2005

19 Weinreb M, "Histomorphometrical analysis of the effects of the bisphosphonate alendronate on bone loss caused by experimental periodontitis in monkeys" 29 (29): 35-40, 1994

20 Cui X-j, "Fabrication and corrosion resistance of a hydrophobic micro-arc oxidation coating on AZ31 Mg alloy" 90 : 402-412, 2015

21 Ma Q, "Enhancement of the bioactivity of titanium oxide nanotubes by precalcification" 62 : 3035-3038, 2008

22 Van Phuong N, "Enhanced corrosion performance of magnesium phosphate conversion coating on AZ31 magnesium alloy" 27 (27): 1087-1095, 2017

23 Nguyen T-DT, "Enhanced biocompatibility of a pre-calcified nanotubular TiO2layer on Ti–6Al–7Nb alloy" 236 : 127-134, 2013

24 Duan H, "Electrochemical corrosion behavior of composite coatings of sealed MAO film on magnesium alloy AZ91D" 51 (51): 2898-2908, 2006

25 Chung H, "Effect of potassium hydroxide treatment of titanium implant on the precipitation of calcium phosphate and tissue compatibility" 28 : 223-233, 2001

26 Lee SJ, "Effect of bisphosphonates on anodized and heat-treated titanium surfaces : an animal experimental study" 82 (82): 1035-1042, 2011

27 Upadhyay D, "Corrosion of alloys used in dentistry : A review" 432 (432): 1-11, 2006

28 Su Y, "Composite microstructure and formation mechanism of calcium phosphate conversion coating on magnesium alloy" 163 (163): G138-, 2016

29 Moreau M-F, "Comparative effects of five bisphosphonates on apoptosis of macrophage cells in vitro" 73 (73): 718-723, 2007

30 Sharma D, "Bisphosphonate-related osteonecrosis of jaw(BRONJ) : diagnostic criteria and possible pathogenic mechanisms of an unexpected antiangiogenic side effect" 5 (5): 1-8, 2013

31 Khan AA, "Bisphosphonate associated osteonec"rosis of the jaw" 36 (36): 478-490, 2009

32 Cui W, "Biomimetic coating of magnesium alloy for enhanced corrosion resistance and calcium phosphate deposition" 9 (9): 8650-8659, 2013

33 Kodama A, "Bioactivation of titanium surfaces using coatings of TiO2 nanotubes rapidly pre-loaded with synthetic hydroxyapatite" 5 (5): 2322-2330, 2009

34 Ishizaki T, "Anticorrosive magnesium phosphate coating on AZ31 magnesium alloy" 203 (203): 2288-2291, 2009

35 Reddy MS, "Alendronate treatment of naturally-occurring periodontitis in beagle dogs" 66 (66): 211-217, 1995

36 Peuster M, "A novel approach to temporary stenting : degradable cardiovascular stents produced from corrodible metal—results 6–18 months after implantation into New Zealand white rabbits" 86 (86): 563-569, 2001

37 Dearnley P, "A brief review of test methodologies for surface-engineered biomedical implant alloys" 198 (198): 483-490, 2005