Application Of Nanomaterials In Biological Analysis

Nanomaterial is a solid system which is comprised by the size of particles from 1 to 100 nm. These systems typically include sensor nanomaterials, molecules, bioimaging technology, drug delivery and DNA transport. Therefore, nanomaterials are quite extensive applications in biomedical, biochemical analysis, mechanical and magnetic. Due to its size effect, quantum effect, surface effect and interfacial effects. Nanomaterials not only have the normal properties, which are similar to the traditional materials, but also have the new excellent properties, which the traditional materials do not possess. The catalyst is one of the important applications of nanomaterials. Nanoparticles have a high specific surface area, which has the characteristics of the bond states and the electronic states of the surface atoms beyond the internal atoms. Since the surface active sites increases, the nanoparticles can act as a catalyst prerequisite. Nanobiotechnology comes from nanotechnology and biotechnology and use nanotechnology to solve the biological problems. For example, fluorescent nanomaterial can be used as a luminescent marker in biological chips, due to its high quantum yield, long emission lifetime and stable performance. Furthermore a variety of biosensors based on nanomaterial is very widely used in biological applications. In this paper we describe two projects:1) two ligands-coated gold nanorods as localized surface plasmon Label-free detection of O-GlcNAcylated Proteins, and 2) graphene quantum dots in a cell imaging.O-GlcNAcylation, a new type of post-translational modification of proteins, plays an essential role in various cellular processes and is closely related to some fatal diseases such as cancers. An advanced method is greatly desired to efficiently analyse O-linked β-N-acetylglucosamine(O-GlcNAc) and further elucidate its key biological roles. Gold nanorods(Au NRs) is a special photophysical and photochemical properties of special nanomaterials. It has low toxicity, biocompatibility, electrical conductivity and strong and good dispersion. In this work, a label-free approach was developed with dual ligands-capped gold nanorod(Au NRs) as a localized surface Plasmon resonance(LSPR) transducer for detection of O-GlcNAcylated proteins. Two kinds of alkanethiols carboxyl-PEG-thiol(COOH-PEG-SH) and mercaptosuccinic acid(MSA) are conjugated on surface of Au NRs via ligand exchange. The ligands provide inner and outer layer of carboxyl functional group surrounding Au NRs, resulting in high loading capacity of wheat germ agglutinin(WGA) lectin. The COOH-PEG-SH works as a protection layer making Au NRs a good monodispersity and a high stability. The high probe loading capacity and good stability contribute the sensitive label-free detection. O–GlcNAc levels in normal and cancer cells were successfully analysed by the developed LSPR sensor WGA–functionalized Au NRs(WGA–Au NRs). In addition, effect of OGA inhibitor on protein O-GlcNAcylation was also evaluated with same sensing system. This work provides a promising analytical tool for glycomics research and cancer diagnostics. Graphene quantum dots(GQDs) are prepared by nitric acid treated XC-72 carbon black. It has good water solubility, good fluorescence, salt resistance, light stability and good biocompatibility. TEM images display the particle sizes having the range of 2-3 nm and a uniform distribution. After synthesis of GQDs, they are added into the biological cells to study the effect. The bright green area inside the cell can be observed by the fluorescence microscopy, revealing that GQDs can transport through the cell membrane and demonstrating that the possible applications of GQDs in the biological imaging area. MTT method is used to indirectly counting the living cell through the measurement the optical absorbance. After 24-hour cell culture, their cellular activity is also around 100%, revealing that at certain concentration, GQDs have few effects on cell viability. MTT colorimetric analysis also shows that GQDs exhibit good intracellularly light stability and low cytotoxicity.