BIOMOMENTUM力學試驗機--游離鈣的變化改變椎間盤的機械性能

由于我們近發現人椎間盤（IVD）中游離鈣（Ca 2+）濃度升高會導致基質降解（Grant等人ECM 2016），因此我們假設Ca 2+升高也會損害IVD力學。這項研究的目的是確定游離Ca 2+對IVD力學性能的影響。

從25個月大的牛尾中分離出IVD，并與1mM或5mM Ca 2+孵育4周。沒有鈣補充的IVD被認為是對照。使用Mach-1機械測試儀（加拿大Biomomentum Inc.），對每個IVD進行壓縮動態機械測試（DMA），以使用5％的應變幅度在0.01Hz至5Hz的頻率范圍內評估其體積楊氏模量（E *）。隨后，為了評估隔室的剛度，將IVD沿脊髓分為兩半，并使用自動球形壓痕技術（R = 3.2mm，15度量/ cm 2，振幅= 0.5 ）評估每半的中央部分毫米）。生成剛度圖。

與對照相比，在1mM或5mM Ca 2+中孵育4周后，E *明顯降低。與低Ca 2+濃度（1mM）的對照相比，IVD隔室的剛度幾乎保持不變，而在高
濃度（5mM）時達到顯著（p <0.0001 ）。纖維環（AF）的剛度從0.30±0.02MPa降低到0.06±0.01MPa。然而，對于髓核（NP）和終板（EP），組織剛度分別從0.030±0.001MPa增加到0.060±0.002MPa，從1.45±0.15MPa增加到2.5±0.07MPa
。

CHANGES IN FREE CALCIUM ALTER THE MECHANICAL PROPERTIES OF THE INTERVERTEBRAL DISC
Since we recently discovered that increased free calcium (Ca2+) concentration in the human intervertebral disc (IVD) leads to matrix degradation (Grant et al. ECM 2016), we hypothesized that elevations in Ca2+ also impair IVD mechanics. The aim of this study was to determine the effect of free Ca2+ on the mechanical properties of the IVD.

IVDs were isolated from 25-month-old bovine tails and incubated for 4 weeks with either 1mM or 5mM Ca2+. IVDs without calcium supplementation were considered as control. Using the Mach-1 mechanical tester (Biomomentum Inc, Canada), each IVD was subjected to compressive dynamic mechanical testing (DMA) to assess its bulk Young's modulus (E*) for frequencies ranging from 0.01Hz to 5Hz using 5% strain amplitude. Subsequently, to assess the compartmental stiffness, the IVDs were divided in two halves along the spinal cord, and the central section of each half was assessed using an automated spherical indentation technique (R=3.2mm, 15 measures/cm2, amplitude=0.5mm). Stiffness maps were generated.

After a 4-week incubation period in 1mM or 5mM Ca2+, E* decreased significantly compared to the control. Stiffness of IVD's compartments remained almost unchanged when compared to the control for low Ca2+ concentration (1mM), while it reached significance (p<0.0001) at the high
concentration (5mM). The stiffness decreased in annulus fibrosus (AF) from 0.30±0.02MPa to 0.06±0.01MPa. However, for both nucleus pulposus (NP) and endplates (EP), tissues stiffness increased from 0.030±0.001MPa to 0.060±0.002MPa and from 1.45±0.15MPa to 2.5±0.07MPa,
respectively.
High Ca2+ concentration alters IVD's bulk and compartmental mechanical properties. These results are consistent with our previous findings suggesting that increasing the calcium levels resulted in increases in the mineralisation of EP, and decrease the diffusion of nutrient into the disc. Consequently, assessing mechanical properties of each IVD's compartment may provide a better understanding of its bulk mechanical behavior and its integrity during degeneration.

Adapted from: I. Hadjab, M.P. Grant, L.M. Epure, M. Garon, E. Quenneville, J. Anthoniou, F. Mwale and M.D. Buschmann. Changes in Free Calcium Alter the Mechanical Properties of the Intervertebral Disc. International Conference on the Mechanics of Biomaterials and Tissues, Hawaii, USA, 12Dec2017, Podium O.48. 

biomomentum多軸機械測試儀Mach-1
 Mach-1多軸機械測試儀是模塊化集成壓縮，拉伸，剪切，摩擦，扭轉和3D壓痕映射、電位分布等測試設備
   biomomentum至1999年以來，專注用于測試生物材料，組織和關節軟骨機-電特性產品的設計、開發、制造和商業化的創新解決方案20余年。
    其mach-1多軸向多功能組織材料機械特性測試分析系統已經成為組織材料機械-電位測試分析的黃金標準。
  1、多功能、多軸向，適用樣品范圍廣：
•1.1、從骨等硬組織材料到腦組織、眼角膜等極軟的組織材料
•1.2、從粗的椎間盤的樣品到極細的單纖維絲
2、力學類型測試分析功能齊全：
2.1、模塊化集成壓縮、張力、剪切、摩擦、扭轉、穿刺、摩擦和非平面壓痕、3D厚度、3D表面輪廓等各種力學類型支持,微觀結構表征及動態力學分析研究
2.2、多物理場耦合加載測試
•3、通高量壓痕、壓縮測試分析（48孔板中壓痕測試分析）
•4、高精度、高分辨率:
•4.1、位移分辨率達0.1um
•4.2、力分辨率達0.025mN
•4.3、樣品直徑小25um
•5、行程范圍廣：50-250mm
•6、體積小巧、可放入培養箱內
•7 、DIC （Digital Image Correlation)數字圖像相關法非接觸式的高精度位移、應變測量
•9、活性組織電位分布測試分析
•10、產品成熟，文獻量達上千篇
biomomentum多軸機械測試儀Mach-1材料力學性能簡介：
biomomentum多軸機械測試儀Mach-1材料力學性能是指材料在不同環境(溫度、介質、濕度)下，承受各種外加載荷(拉伸、壓縮、彎曲、扭轉、沖擊、交變應力等)時所表現出的力學特征。
可以放進標準培養箱里進行培養；
biomomentum多軸機械測試儀Mach-1測試意義及適用范圍：
材料力學性能可以應用到生產的任何階段，從測試原材料質量直到檢查制成品的耐用性。 測試可對廣泛多樣的生物樣品、材料和產品進行，包括軟組織、軟骨組織、皮膚組織、凝膠組織、高分子材料、生物產品、醫學鑒定和水凝膠等。力學性能測試可幫助企業向客戶證明其產品的力學性能、穩定性和安性，從而獲得基礎數據和競爭勢。
1、多功能、多軸向，適用樣品范圍廣：
1.1、從骨等硬組織材料到腦組織、眼角膜等極軟的組織材料
1.2、從粗的椎間盤的樣品到極細的單纖維絲
2、力學類型測試分析功能齊全：
2.1、模塊化集成壓縮、張力、剪切、摩擦、扭轉、穿刺、摩擦和非平面壓痕、3D厚度、3D表面輪廓等各種力學類型支持,微觀結構表征及動態力學分析研究
2.2、多物理場耦合加載測試