Materials Science & Engineering Division, National Institute of Standards and Technology , Gaithersburg, MD 20899, United States.
Biomacromolecules. 2013 Feb 11;14(2):377-86. doi: 10.1021/bm301557y. Epub 2013 Jan 18.
A two-dimensional model of a solid-supported enzyme catalyst bead is fabricated on a quartz crystal microbalance with dissipation monitoring (QCM-D) sensor to measure in situ interfacial stability and mechanical properties of Candida antarctica Lipase B (CAL B) under varied conditions relating to ring-opening polymerization. The model was fabricated using a dual photochemical approach, where poly(methyl methacrylate) (PMMA) thin films were cross-linked by a photoactive benzophenone monolayer and blended cross-linking agent. This process produces two-dimensional, homogeneous, rigid PMMA layers, which mimic commercial acrylic resins in a QCM-D experiment. Adsorption of CAL B to PMMA in QCM-D under varied buffer ionic strengths produces a viscoelastic enzyme surface that becomes more rigid as ionic strength increases. The rigid CAL B/PMMA interface demonstrates up to 20% desorption of enzyme with increasing trace water content. Increased polycaprolactone (PCL) binding at the enzyme surface was also observed, indicating greater PCL affinity for a more hydrated enzyme surface. The enzyme layer destabilized with increasing temperature, yielding near complete reversible catalyst desorption in the model.
采用石英晶体微天平耗散监测（QCM-D）传感器，制备了一种固态酶催化剂珠的二维模型，以测量与开环聚合有关的不同条件下南极假丝酵母脂肪酶 B（CAL B）的界面稳定性和力学性能。该模型采用双光化学方法制备，其中聚甲基丙烯酸甲酯（PMMA）薄膜通过光活性二苯甲酮单层和混合交联剂交联。该过程产生二维、均匀、刚性的 PMMA 层，在 QCM-D 实验中模拟商业亚克力树脂。在 QCM-D 中，在不同缓冲离子强度下，CAL B 在 PMMA 上的吸附产生了具有粘性的酶表面，随着离子强度的增加，该表面变得更加刚性。刚性的 CAL B/PMMA 界面显示，随着痕量水分含量的增加，酶的解吸率高达 20%。还观察到聚己内酯（PCL）在酶表面的结合增加，表明更水合的酶表面对 PCL 具有更大的亲和力。随着温度的升高，酶层失稳，在模型中几乎完全可逆地催化剂解吸。
