Biomimetic compartmentalization approach in designing nanoreactor with organelle-like function

Introduction In nature, biological cell is regarded as an intricated microenvironment, in which myriad of enzymes work together to catalyze concurrently multiple chemical reactions concurrently that are crucial for metabolism... [ view full abstract ]

Introduction
In nature, biological cell is regarded as an intricated microenvironment, in which myriad of enzymes work together to catalyze concurrently multiple chemical reactions concurrently that are crucial for metabolism and cell functions. Inspired by nature, scientists manifest an increasing interest to mimic these compartmentalized enzyme regulatory mechanisms, not only to understand the biological process of cellular metabolism and functions, but most importantly to design customized biomimetic nanomachineries with a tremendous potential in a range of applications from biochemicals, pharmaceutics, diagnostics to, biomedicine, smart materials, and synthetic organelles. Therefore, mimicking the chemical transformations exhibited by enzymes in cellular compartments has triggered intensive research interest for creating new dynamic materials with tunable enzyme reactivity. In this work, we aim to develop a compartmentalized cellular nanoreactor consisting of porous silicon nanoparticles (PSi NPs) entrapped with an enzyme, horseradish peroxidase (HRP), and surface coated with a cancer cell membranes to demonstrate the design of biomimetic cellular nanoreactors and their impact on improving cellular functions for biomedical applications.

Methods
PSi NPs have been used as host material to the entrapment of HRP enzymes within the pores. To construct a compartmentalized cellular nanoreactor, purified cancer cell membranes coated the surface of PSi NPs by an extrusion. The enzyme activity and kinetics of the compartmentalized cellular nanoreactors were evaluated using an enzymatic assay. To demonstrate the function of biomimetic cellular nanoreactors in improving cellular functions, different in-vitro cell experiments were performed.

Results and Discussion
The results from the physicochemical characterization of nanoreactors indicate the successful loading of HRP in PSi NPs and the cancer cell membrane surface coating. The enzyme activity and kinetics analyses showed an enhanced substrate affinity and reaction rate compared to free HRP (Figure 1B), suggesting a high catalytic activity of nanoreactors. The in-vitro cell experiments demonstrated that nanoreactors can readily integrate with cells and can supplement the cellular functions under oxidative stress conditions. This cellular nanoreactor featuring a biocompartment enclosed by cellular membrane closely resembling nature’s biocompartmentalization is an innovative biomimetic approach, which further helps the customized designing of biomimetic nanomachineries that can impact the repairing of cellular functions in pathological conditions.