Protein-gold Clusters For Heavy Metal Ions Detection, Cellular Imaging, And Drug Delivery

Gold nanoclusters were composed of several hundred gold atoms, their size in nano level,so it is a kind of new luminescent materials. Because of the particularity of its size, itsproperties were in gold and gold nanoparticles with large atomic. At the same time goldnanoclusters can show the surface effect, volume effect, quantum size effect, macroscopicquantum tunneling effect and dielectric confinement effect. Which leads to the nano materialwith other sizes with photoelectric properties of different physical and chemical properties? Inthe applications of gold nanoclusters, compared to other types of fluorescent material hasmany advantages. Firstly, some organic small molecule fluorescent material types, theirluminescent properties are very good, but the duration of light is often very short, resulting ininconvenience in use. The fluorescence quantum dot materials while overcomes thedisadvantages of the luminescence time is short, but because of quantum dot itself has a lot ofmetal materials, and require high temperature and nitrogen protection in the productionprocess, resulting in high cost of production materials. And the light of longer duration ofgold clusters, simple production process, and making use of the protein and other biologicalmaterials of gold clusters, non-toxic, good biological compatibility. And because of somespecial properties of gold clusters and the gold clusters have unique photochemical properties.It is applied to the detection of gold clusters, such as the effective components, detection ofmetal ions, drugs and some small biological molecules.In this paper, according to the properties of gold clusters are special, protected goldclusters by protein synthesis, applied to the study of metal ion detection. Then according tothe properties of gold clusters itself coated gold cluster is applied to cell imaging and drugdelivery.a-chymotrypsin A (CTRA), as an important enzyme in medical research, was used todirect the synthesis of gold nanoclusters in a mild condition. AuNCs@CTRA werecharacterized using UV-vis spectra, fluorescence spectra, XPS spectra and TEM. The AuNCssynthesized using “green method” was transferred to a cellulose membrane by takingadvantage of blotting technology. The AuNCs@CTRA–cellulose membrane can serve as anefficient sensor for mercury ion detection with high selectivity and sensitivity. The signalsfrom this dual role system can be easily readout under a UV light (fluorometric) or visuallydetected by naked eye (colorimetric). Based on these results, we propose that this systemcould act as an alternative analytic tool for Hg2+detection in life sciences and pollutionresearch. Incubation of gold (III) chloride trihydrate with BSA at97C for15min at the alkalic pHresulted in formation of crosslinked proteins with CP-GNC. The size, shape, fluorescence,and amphoteric nature of CP-GNC suggest that this material can function as a tool inbioimaging and drug delivery. The rod-shaped CP-GNC is highly fluorescent andapproximately100nm in diameter and700nm in length. CP-GNC attaches to bacterial cellsat low pH and detaches from the cells at high pH. Furthermore, CP-GNC potentiated theability of low antibiotic concentrations to restrict bacterial growth. Therefore, this materialmay serve as a pH controllable and recyclable tool for fluorescent cell labeling and antibioticdelivery.