Phenylboronic acid functionalized reduced graphene oxide based fluorescence nano sensor for glucose sensing.

Reduced graphene has emerged as promising tools for detection based application of biomolecules as it has high surface area with strong fluorescence quenching property. We have used the concept of fluorescent quenching property of reduced graphene oxide to the fluorescent probes which are close vicinity of its surface. In present work, we have synthesized fluorescent based nano-sensor consist of phenylboronic acid functionalized reduced graphene oxide (rGO-PBA) and di-ol modified fluorescent probe for detection of biologically important glucose molecules.

β-Cyclodextrin functionalized magnetic mesoporous silica colloid for cholesterol separation.

Although cholesterol plays significant biochemical function in the human body, excess of it leads to various disorders, and thus, its control/separation is important in medical science and food industries. However, efficient and selective separation of cholesterol is challenging because cholesterol often exists in microheterogeneous or insoluble forms in remote organ and exists with other chemicals/biochemicals. Here, we have described a colloidal magnetic mesoporous silica (MMS)-based approach for efficient separation of cholesterol in different forms.

Synthesis of nanobioconjugates with a controlled average number of biomolecules between 1 and 100 per nanoparticle and observation of multivalency dependent interaction with proteins and cells.

Multivalency of nanoparticle and associated cooperative binding with biological interface is an important aspect in the development of nanoparticle based bioimaging probes. However, the preparation of such a nanobioconjugate with a controlled number of biomolecules per nanoparticle, typically between 1 and 100, is challenging. Here we report a generalized two-step bioconjugation method to prepare nanobioconjugates with a varied average number of biomolecules between 1 to 100 per nanoparticle that can be applied to different nanoparticles and biomolecules.

Doped semiconductor nanocrystal based fluorescent cellular imaging probes.

Doped semiconductor nanocrystals such as Mn doped ZnS, Mn doped ZnSe and Cu doped InZnS, are considered as new classes of fluorescent biological probes with low toxicity. Although the synthesis in high quality of such nanomaterials is now well established, transforming them into functional fluorescent probes remains a challenge. Here we report a fluorescent cellular imaging probe made of high quality doped semiconductor nanocrystals.

Thiol-directed synthesis of highly fluorescent gold clusters and their conversion into stable imaging nanoprobes.

Fluorescent gold clusters (FGCs) with tunable emission from blue to red and quantum yields in the range of 6-17% have been synthesized by simple modification of the conditions used for the synthesis of gold nanoparticles, namely by replacing the stronger reducing agent with a controlled amount of thiol. Various functional FGCs with hydrodynamic diameters of 5-12 nm have been successfully synthesized and used as cell labels. The results of our investigations strongly indicate that FGCs composed of Au(0) are more stable imaging probes than commonly reported red/NIR-emitting FGCs with a composition of Au(0)/Au(I), as this combination rapidly transforms into nonfluorescent large clusters on exposure to light.

Functionalized graphene and graphene oxide solution via polyacrylate coating.

Water soluble graphene with various chemical- and biofunctionalities is essential for their different applications. However, exfoliated graphenes are insoluble in water and water soluble graphene oxide precipitate if they are chemically reduced to graphene. We have developed a polyacrylate coating method for graphene oxide and then chemically reduced it into graphene.

Highly fluorescent magnetic quantum dot probe with superior colloidal stability.

A magnetic quantum dot (MQD) based cellular nanoprobe, composed of a magnetic oxide nanoparticle component and a quantum dot component, has been synthesized and used for both imaging and separation. The successful synthesis is based on a reverse micelle based polyacrylate coating in the presence of component nanoparticles, followed by their functionalization via conjugation chemistry.

Ligand exchange approach in deriving magnetic-fluorescent and magnetic-plasmonic hybrid nanoparticle.

We report here ligand-exchange-based synthesis of magnetic-plasmonic and magnetic-fluorescent hybrid nanoparticles such as gamma-Fe(2)O(3)-QD, gamma-Fe(2)O(3)-Au, and gamma-Fe(2)O(3)-Ag. In this approach the surface ligands of hydrophobic gamma-Fe(2)O(3) nanoparticles are replaced by terminal amine/carboxylate functional groups of core-shell type hydrophilic QD/Au/Ag nanoparticle, with a resultant water-soluble hybrid nanoparticle. These water-soluble hybrid materials exhibit good colloidal stability, retain the property of each component nanoparticle, and are approximately 20-35 nm in diameter.

Functionalized gold nanorod solution via reverse micelle based polyacrylate coating.

Functionalization of gold nanorods is a key issue for their biomedical application, and currently it is performed via either electrostatic interaction or thiol based strategy. We have developed a polyacrylate based coating chemistry for gold nanorods that can be used in deriving a variety of functional nanorods with high colloidal stability. The coating processes can introduce primary amines, fluorescein, or poly(ethylene glycol) (PEG) on the nanorod surface in one step process.