Understanding the influencing factors on the reaction kinetics of P450 BM3 within confined spaces is essential for developing efficient P450 BM3 bioreactors. Herein, two dendritic mesoporous silica nanoparticles (OH-DMSNs and NH₂-DMSNs) with similar pore size but opposite surface charge have been prepared and served as the vehicle to immobilize P450 BM3. With the help of the film-forming material of chitosan, P450 BM3/OH-DMSN and P450 BM3/NH₂-DMSN composites were immobilized on GC electrode and characterized with electrochemical measurements. Compared with P450 BM3/OH-DMSNs/GCE, P450 BM3/NH₂-DMSNs/GCE showed higher electron transfer efficiency with higher current charge and lower k_s value. Besides, the generated catalytic current towards testosterone on P450 BM3/NH₂-DMSNs/GCE was 1.81 times larger than P450 BM3/OH-DMSNs/GCE. Furthermore, P450 BM3 inside NH₂-DMSNs displayed higher affinity towards testosterone with the lower K_m^app value of 244.82 μM. These results are attributed to the positively charged internal walls of NH₂-DMSNs so that P450 BM3 adapts to an orientation favorable for electron exchange with electrodes and substrate binding with the active sites. The present study provides fundamentals for regulating the surface charge to optimize redox process and catalytic behavior in CYP bioreactors through electrostatic interactions.

了解受限空间内P450 BM3反应动力学的影响因素对于开发高效的P450 BM3生物反应器至关重要。在此，已经制备了具有相似的孔径但相反的表面电荷的两个树枝状介孔二氧化硅纳米粒子（OH-DMSN和NH ₂ -DMSN），并用作固定P450 BM3的载体。借助壳聚糖的成膜材料，将P450 BM3 / OH-DMSN和P450 BM3 / NH ₂ -DMSN复合材料固定在GC电极上，并进行电化学测量。与P450 BM3 / OH-DMSNs / GCE相比，P450 BM3 / NH ₂ -DMSNs / GCE表现出更高的电子传输效率，更高的电流电荷和更低的k _s值。此外，在P450 BM3 / NH ₂ -DMSNs / GCE上产生的朝向睾丸激素的催化电流是P450 BM3 / OH-DMSNs / GCE的1.81倍。此外，NH ₂ -DMSN内的P450 BM3对睾丸激素表现出更高的亲和力，而K _m ^app值较低，为244.82μM。这些结果归因于NH ₂ -DMSN的带正电的内壁，因此P450 BM3适应于有利于与电极进行电子交换以及与活性位点结合的底物的取向。本研究为调节表面电荷以通过静电相互作用优化CYP生物反应器中的氧化还原过程和催化行为提供了基础。