Wakefield Jennifer M K, Gillis Richard B, Adams Gary G, McQueen Caitlin M A, Harding Stephen E
National Centre for Macromolecular Hydrodynamics (NCMH), School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK.
School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
Eur Biophys J. 2018 Oct;47(7):769-775. doi: 10.1007/s00249-018-1290-6. Epub 2018 Mar 17.
The heterogeneity and molecular weight of a chitosan of low molecular weight (molar mass) and low degree of acetylation (0.1) for potential use as a consolidant for decayed archaeological wood were examined by sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge before and after depolymerisation. Sedimentation velocity before depolymerisation revealed a uniform distribution of sedimentation coefficient with little concentration dependence. SEDFIT-MSTAR analysis revealed a weight average molecular weight M of (14.2 ± 1.2) kDa, and polydispersity index of ~ 1.2. Further analysis using MULTISIG revealed a distribution of material between 2 and 20 kDa and consistent with the weight average M. Controlled depolymerisation using hydrogen peroxide and ultra-violet radiation in an acetic acid medium reduced this to (4.9 ± 0.7) kDa, with a similar polydispersity. The depolymerised material appears to be within the range that has been predicted to fully penetrate into archaeological wood. The consequences for this finding and the use of the analytical ultracentrifuge in wood conservation strategies are considered.
通过分析超速离心机在解聚前后的沉降速度和沉降平衡，研究了一种低分子量（摩尔质量）和低乙酰化度（0.1）的壳聚糖作为腐朽考古木材加固剂的潜在用途时的异质性和分子量。解聚前的沉降速度显示沉降系数分布均匀，浓度依赖性小。SEDFIT-MSTAR分析显示重均分子量M为(14.2±1.2) kDa，多分散指数约为1.2。使用MULTISIG的进一步分析显示材料分布在2至20 kDa之间，与重均M一致。在乙酸介质中使用过氧化氢和紫外线辐射进行可控解聚，使其降至(4.9±0.7) kDa，多分散性相似。解聚后的材料似乎在预计能完全渗透到考古木材中的范围内。考虑了这一发现的后果以及分析超速离心机在木材保护策略中的应用。
