科研之友
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摘要
Zeta potential and avidin adsorption of silicone elastomer (SE) and SE coated with polyethyleneimine (PEI) and heparin is studied under controlled hydrodynamic conditions. Zeta potential (zeta) of SE depends on the duration of contact with buffer (0.02M MOPS-KCl, pH 7.2): zeta descends from 12 mV to a plateau value of -32 mV during 5 h and decreases further if SE is stretched (30% elongation). The time variation of zeta is attributed to surface charging of the core polymer PDMS. Coating the negatively charged SE with PEI results in zeta = 42 my; a layer of heparin on top of PEI yields zeta = -46 mV. On the negatively charged surfaces, avidin adsorption levels off at 5 mV. Desorption of avidin from SE is negligible even when SE with adsorbed avidin is stretched, or when the stretching force is removed after adsorption of avidin. The results can be employed for designing biomaterials with properties such as surface charge and protein adsorption adjustable by stretching; the strong attachment of avidin can allow for further surface modification.
- 出版日期2013-8-1
