ZIF-67基Ni-Co类水滑石的合成及其固定化辣根过氧化物酶的研究

Synthesis of ZIF-67 based Ni-Co layered double hydrotalciteand its immobilization of horseradish peroxidase

采用纳米级ZIF-67型金属有机骨架材料为基体,利用镍离子溶液对ZIF-67纳米粒子进行刻蚀改性,合成具备微/介孔结构的ZIF-67基Ni-Co类水滑石(LDH@ZIF-67)。以LDH@ZIF-67为酶载体通过孔道扩散法制备了负载辣根过氧化物酶(HRP)的HRP@LDH@ZIF-67,研究了刻蚀时间对酶负载量的影响。结果表明,经镍离子溶液刻蚀处理1 h后,LDH-1@ZIF-67仍保持与ZIF-67近似的晶型与粒径,但粒子表面为层状类水滑石形貌,且形成了10~30 nm的介孔结构。HRP@LDH-1@ZIF-67的负载量可达48.63 mg/g,进一步考察了所得HRP@LDH@ZIF-67的酶活、稳定性以及重复使用性。相较于游离HRP,所得HRP@LDH@ZIF-67展现出较优的催化活性、更宽的使用温度范围、良好的耐酸碱性和重复使用性。

ZIF-67 based Ni-Co layered double hydroxides(LDH@ZIF-67)with micro/meso-porous structures were synthesized by etching ZIF-67 nanoparticles with nickel ions.The prepared LDH@ZIF-67 was used as enzyme carrier to immobilize horseradish peroxidase(HRP)through pore diffusion method,giving immobilized HRP on LDH@ZIF-67(HRP@LDH@Zif-67).The effects of different LDH@ZIF-67 carriers on enzyme loadings were studied.The results showed that the LDH-1@ZIF-67 was etched by nickel ions for 1 h still kept a crystalized structure and the particle size similar to ZIF-67 nanoparticles,but LDH-1@ZIF-67 exhibited the surface morphology of layered double hydroxides and formed mesopores with the pore size of 10~30 nm.The load of HRP@LDH-1@ZIF-67 can reach 48.63 mg/g,and the enzyme activity,stability and reusability of HRP@LDH-1@ZIF-67 were studied.Compared with free HRP,HRP@LDH@ZIF-67 shows better catalytic activity,wider temperature range,good alkali resistance and reusability.