Department of General Dental Sciences, School of Dentistry, Marquette University, Milwaukee, WI, 53233, United States; Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, Chicago, IL, 60612, United States.
Pharmacognosy Institute and Department of Pharmaceutical Sciences (PSCI), College of Pharmacy, University of Illinois at Chicago, Chicago, IL, 60612, United States.
Dent Mater. 2021 Nov;37(11):1633-1644. doi: 10.1016/j.dental.2021.08.013. Epub 2021 Sep 23.
To elucidate the structure-activity relationships (SARs) of proanthocyanidins (PACs) with type I collagen using sixteen chemically defined PACs with degree of polymerization (DP) 2-6.
Under a dentin model, the biomimicry of PACs with type I collagen was investigated by dynamic mechanical analysis (DMA) and infrared spectroscopy. The dentin matrix was modified with PACs from Pinus massoniana [monomers (Mon-1 and Mon-2), dimers (Dim-1-Dim-4), trimers (Tri-1-Tri-4), tetramers (Tet-1-Tet-5), and hexamer (Hex-1)]. A strain sweep method in a 3-point bending submersion clamp was used to assess the viscoelastic properties [storage (E'), loss (E"), and complex moduli (E*) and tan δ] of the dentin matrix before and after biomodification. Biochemical analysis of the dentin matrix was assessed with FTIR spectroscopy. Data were statistically analyzed using one-way ANOVA and post-hoc tests (α = 0.05).
DP had a significant effect on modified dentin moduli (tetramers ≈ trimers > hexamers ≈ dimers > monomers ≈ control, p < 0.001). Trimers and tetramers yielded 6- to 8-fold increase in the mechanical properties of modified dentin and induced conformational changes to the secondary structure of collagen. Modifications to the tertiary structure of collagen was shown in all PAC modified-dentin matrices.
Findings establish three key SARs: (i) increasing DP generally enhances biomimicry potential of PACs in modulating the mechanical and chemical properties of dentin (ii) the secondary structure of dentin collagen is affected by the position of B-type inter-flavanyl linkages (4β → 6 and 4β → 8); and (iii) the terminal monomeric flavan-3-ol unit plays a modulatory role in the viscoelasticity of dentin.
使用聚合度（DP）为 2-6 的十六种化学定义的原花青素（PACs）阐明原花青素与 I 型胶原蛋白的结构-活性关系（SARs）。
在牙本质模型下，通过动态力学分析（DMA）和红外光谱研究 PAC 与 I 型胶原蛋白的仿生关系。用马尾松 PAC 修饰牙本质基质[单体（Mon-1 和 Mon-2）、二聚体（Dim-1-Dim-4）、三聚体（Tri-1-Tri-4）、四聚体（Tet-1-Tet-5）和六聚体（Hex-1）]。三点弯曲浸泡夹中的应变扫描法用于评估生物修饰前后牙本质基质的粘弹性特性[存储模量（E'）、损耗模量（E"）、复合模量（E*）和 tanδ]。用傅里叶变换红外光谱法对牙本质基质的生物化学分析。使用单向方差分析和事后检验（α=0.05）对数据进行统计学分析。
DP 对修饰牙本质模量有显著影响（四聚体≈三聚体>六聚体≈二聚体>单体≈对照，p<0.001）。三聚体和四聚体使修饰牙本质的机械性能提高了 6-8 倍，并诱导胶原蛋白二级结构发生构象变化。所有 PAC 修饰牙本质基质均显示胶原蛋白三级结构发生变化。
研究结果确立了三个关键 SARs：（i）DP 增加通常增强 PAC 调节牙本质机械和化学性质的仿生潜力；（ii）牙本质胶原蛋白的二级结构受 B 型间黄烷醇键位置（4β→6 和 4β→8）影响；（iii）末端单体黄烷-3-醇单元在牙本质粘弹性中起调节作用。
