Development of organic-inorganic hybrid nanomaterials for the biosensing application

Abstract

In recent years, an intense interest has grown in the synthesis of functional hybrid organic-inorganic nanostructured materials. Several research groups have reported different hybrid organic-inorganic nanomaterials by employing organic materials (such as proteins, amino acids, and organic acids) and inorganic materials (such as metal ion and metal nanoparticles). Based on the aforementioned unique combinations of organic-inorganic hybrid nanomaterials, we have developed a novel nanostrucuted materials employed in sensing different biomolecules such $H_2O_2$, glucose, choline, and acetyl choline. In chapter 2, we developed a simple but efficient method to synthesize protein-inorganic hybrid nanostructures with a flower-like shape (nanoflowers), which relies on sonication to facilitate the synthesis of the nanoflowers. With this technique, we synthesized nanoflowers containing laccase as a model enzyme and copper phosphate within 5 minutes at room temperature. The resulting laccase nanoflowers yielded greatly enhanced activity, stability, and reusability, and their usefulness was successfully demonstrated by applying them in the colorimetric detection of epinephrine. In chapter 3, we reported sonicated bovine serum albumin (BSA)-incorporated $Cu_3(PO_4)_2.3H_2O$ nanoflowers (SBSA-NFs) possess an intrinsic peroxidase-mimicking activity and also demonstrate that glucose oxidase (GOx) incorporated in nanoflowers showed enhanced activity compared with free GOx for the detection of target glucose in the cascade reaction, due to the synergistic effect arises from improved spatial coupling between enzymes and peroxidase-mimicking copper(II). In chapter 4, we synthesized different amine grafted MIL-100(Fe) metal organic frameworks (MOFs) and found that N,N,N',N' Tetramethyl- 1, 4- butanediamine (TMBDA)-MIL-100(Fe) showed excellent peroxidase-mimicking activity. Further, we developed detection strategy by employing TMBDA-MIL-100(Fe) for the detection of biomolecules and obtained excellent limit of detection for $H_2O_2$, choline, and acetylcholine with $0.329 \mu M$ , $0.027 \mu M$, and $0.036 \mu M$ respectively. The diagnostic capability of this method is also demonstrated by detecting choline and acetyl choline in serum, showing its great potential in practical application.