The size-dependent optical properties of CdSe nanoparticles are desirable in bio-imaging and cell sorting applications because of their tunable photoluminescence in the visible range. Previous studies have already suggested that CdSe QDs could be utilized for pathogen detection by using suitable capping agents to make it biocompatible; however, systematic works on the effect of crystallite size and composition of the nanocrystals are scarce. The present research will be focused on the effect of CdSe crystal size and composition (pure and doped systems) to systematically evaluate its applicability in detecting pathogens, like Escherichia coli (E. coli). Highly luminescent water-soluble CdSe QDs were firstly synthesized in the aqueous phase, in the presence of thioglycolic acid (TGA) as a capping agent. CdSe/TGA molar ratios, reaction temperature, time, and pH were evaluated in order to optimizer the QDs optical properties. X-Ray diffraction (XRD) measurements confirmed the formation of CdSe exhibiting hexagonal structure with an estimated averaged crystallite size in the 4-6 nm range. Transmission electron microscopy (TEM) analyses evidenced the formation of CdSe nanocrystals with particle sizes between 3-5 nm. UV-Vis measurements showed a strong exciton peak between 390-400 nm with an estimated band gap of 2.64 eV (bulk: 1.74 eV); additionally, a strong fluorescence peak was observed between 500-550 nm using an excitation wavelength of 400 nm. Fourier Transform Infrared Spectroscopy (FT-IR) analyses suggested the actual functionalization of the CdSe surface with TGA functional groups. Preliminary results of the CdSe/TGA coupling with the selected bacteria, E. coli, are presented and discussed.

Medical research has demonstrated the importance of the utilization of stable, fluorescent nanoprobes. The present work addresses the applicability of biocompatible and fluorescent ZnO nanoparticles as probes for detection of pathogens with the aim of achieving extremely low detection limits. For this purpose, ZnO surface must be functionalized for its subsequent interaction with bacterial cellular membrane (coupling), which will allow the corresponding detection and quantification. Herein we will discuss the aqueous synthesis of stable, water soluble and biologically compatible ZnO nanoparticles (NPss) capped with L-glutathione (GSH). The understanding of the interactions between GSH molecules and surface atoms in ZnO QDs became critical to foster the applicability of this nanomaterial in the biomedical and bioengineering fields. In this regard, the GSH/ZnO molar ratios, reaction temperature (40°C and 60°C), time and pH (6-9) became crucial factors to attain suitable tuning of the QDs properties. ZnO/GSH synthesized QDs were characterized by Transmission Electron Microscopy, X-Ray Diffraction, FT-IR, UV-Vis and photoluminescence (PL) spectroscopy. The QDs shape was spherical with a particle size between 80-100nm. The synthesis of ZnO/GSH under different experimental conditions and the corresponding coupling with E. Coli species, are presented and discussed.

Polymeric nanoparticles having redox-active catechol moieties, a common structural motif found in naturally-occurring antioxidants, were developed. We synthesized an amphiphilic catechol-bearing polymer that self-assembled to form nanoparticles with a diameter of 126 nm. The nanoparticles showed enhanced ROS-scavenging activity compared to the small catecholic compound dopamine. Furthermore, the nanoparticles inhibited ROS-mediated angiogenesis as shown by the endothelial cell tube formation assay and the chicken chorioallantoic membrane (CAM) assay.

Molecular imprinting is the process by which molecules are imprinted into the matrix of a material through non-covalent bonding, including hydrogen bonding and van der Waals interactions. In this study hydrogels were imprinted with glaucoma medication with the purpose of creating a reusable ocular drug delivery device with reversible binding sites. The material was synthesized and tested with UV-Vis spectroscopy to determine the concentration of the released drug after twelve hours in distilled water. Modifications were made to the polymer to explore methods required for the proper delivery of the drug over an adequate period of time.