Dimitra Georganopoulou

DNA-Gold Triangular Nanoprism Conjugates

Over the past two decades, there has been an enormous effort to understand, control, and use the relationship between the morphology of nanomaterials and their physical and chemical properties.[1,2] Indeed, a great deal of effort has focused on controlling the size, shape, and composition of nanostructures. However, equally important is the surface chemistry of such structures, especially when one considers that the ratio of surface to bulk atoms is much higher than that in micro- or macroscopic systems. For example, the surface plasmon resonances (SPRs) of nanoparticles are highly dependent upon the dielectric medium that surrounds them, including adlayers of molecules and solvent.[3,4] Catalytic activity of a nanoparticle is also highly dependent upon adsorbate.[5,6] Indeed, the development of ways to control the structure and chemical functionalization of a nanoparticle surface is a major area of research, and has led to the discovery of new properties and applications for this important class of materials.[7] In the case of isotropic metal nanoparticles, functionalization has led to a variety of exciting scientific insights and applications, including the use of nanoparticles for spectroscopic labels,[8] gene-regulation agents,[9] and ultrasensitive biodiagnostic tools.[10] In general, less has been done with anisotropic structures, but there have been some important observations and advances made for nanorod and nanoshell structures.[11–14] For example, Gole and Murphy have reported that gold nanorods functionalized with biotin-disulfide will assemble in an end-to-end manner when interconnecting streptavidin proteins are added to a colloid containing them. The authors concluded that such assembly behavior was indicative of end-selective functionalization.[12] Mann and co-workers described a similar example with oligonucleotide-modified nanorods, but in contrast with the Murphy system, they observe sheet-like assembly of nanorods along their long axes.[11] These results present a challenge to both understand and establish control over the face-selective functionalization of anisotropic nanoparticles.

Psa enzymatic activity: a new biomarker for assessing prostate cancer aggressiveness

With the advent of widespread prostate‐specific antigen (PSA) testing in recent decades, prostate cancer (PCa) has emerged as the most frequently diagnosed non‐skin cancer among men in the U.S. and Europe [1]. Greater screening rates coupled with improved detection methods have caused a controversial upsurge in the number of men undergoing prostate biopsy and subsequent treatment. However, current diagnostic techniques generally suffer from limited ability to identify which seemingly indolent cancers are biologically aggressive [2].

Ferrocene and Maleimide-Functionalized Disulfide Scaffolds for Self-Assembled Monolayers on Gold

A series of ferrocene-based electroactive molecules (EAMs) containing maleimide and disulfide groups in different asymmetric and branched architectures were designed and synthesized. Stable monolayers of each EAM on gold electrodes were confirmed by cyclic voltammetry. Importantly, these EAMs expand the repertoire of monolayer building blocks amenable to modular biofunctionalization for applications in electrochemical biosensor fabrication.

Chip-Based High-Sensitivity Detection of Multiple Disease Biomarkers

Presented in this paper is development of a protocol that employs microarrayed DNA patterns within the channels of an integrated lab-on-a-chip system. The patterned microchannels are used in conjunction with the Bio-Barcode Assay for the rapid multiplexed detection of six DNA disease biomarkers in a single experiment. The successful implementation of the Bio-Barcode Assay in a microfluidic device was further demonstrated by detecting as few as 300 prostate-specific antigen molecules in goat serum samples.