Cerasela Zoica Dinu

Cellular Motors for Molecular Manufacturing

Cells are composed of macromolecular structures of various sizes that act individually or collectively to maintain their viability and perform their function within the organism. This review focuses on one structure, the microtubule, and one of the motor proteins that move along it, conventional kinesin (kinesin 1). Recent work on the cellular functions of kinesins, such as the organization of microtubules during cellular division and the movement of the organelles and vesicles, offers insights into how biological motors might prove useful for organizing structures in engineered environments. Anat Rec, 290:1203–1212, 2007.

Bionanoconjugate-based composites for decontamination of nerve agents.

We have developed enzyme‐based composites that rapidly and effectively detoxify simulants of V‐ and G‐type chemical warfare nerve agents. The approach was based on the efficient immobilization of organophosphorus hydrolase onto carbon nanotubes to form active and stable conjugates that were easily entrapped in commercially available paints. The resulting catalytic‐based composites showed no enzyme leaching and rendered >99% decontamination of 10 g/m2 paraoxon, a simulant of the V‐type nerve agent, in 30 minutes and >95% decontamination of diisopropylfluorophosphate, a simulant of G‐type nerve agent, in 45 minutes. The formulations are expected to be environmentally friendly and to offer an easy to use, on demand, decontamination alternative to chemical approaches for sustainable material self‐decontamination.

Optical manipulation of microtubules for directed biomolecule assembly

Optical trapping provides the ability to directly manipulate nano-objects in synthetic environment and hold the potential to produce the next generation of nanodevices. We report a computer-controlled strategy based on dynamic holographic optical trapping to efficiently capture and optically manipulate individual microtubules (25 nm in diameter and several µm in length) as well as hybrid complexes formed from microtubules and quantum dots, with nanometer spatial resolution (15 nm), in three dimensions (over distances exceeding 50 µm in the x–y plane and 10 µm in the z direction), in stationary flow and on engineered surfaces. We also show that individual hybrid complexes can be captured and manipulated for the assembly of user-directed architectures. This strategy can be used for the automated nanofabrication of complex macromolecular architectures and development of novel hybrid materials.

Cell-Based Detection Using Electric Cell-Impedance Sensing

Electric Cell-Impedance Sensing (ECIS) is a real-time transduction system that can be used to detect the presence of foreign particles or pathogens by measuring the changes in impedance or resistance of a cell monolayer grown on an electrode. Herein, we present the use of ECIS for the detection of the toxicity of silver nanoparticles on Madine Derby Canine Kidney (MDCK) epithelial cells as a function of changes in the cell confluence and barrier function of the cell monolayer. The barrier function is a measure of the number of tight junctions formed between confluent cells in a monolayer; tighter confluence leads to an increase in a barrier function and thus in the measured resistance. We were able to detect exposures as low as 1 μg of 20 nm silver nanoparticles per 10 5 cells within 2 hours; those exposures were quantified as a significant drop in impedance and a gradual decrease in the barrier function as compared to the controls. Future work would include the detection of protein toxins using impedance sensing as well as further analysis of the barrier function using fluorescent staining.