Reversible diels-alder chemistry as a modular polymeric color switch

(Figure Presented) A fully reversible polymeric color-switch system based on reversible Diels-Alder chemistry between cyclopentadienyl capped polymers and highly electron deficient dithioesters is described. The detailed reaction progress could be mapped on a molecular level for several complete switching cycles and was underpinned by an ESI-MS study. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Catalytically active single-chain polymeric nanoparticles: exploring their functions in complex biological media

Dynamic single-chain polymeric nanoparticles (SCPNs) are intriguing, bioinspired architectures that result from the collapse or folding of an individual polymer chain into a nanometer-sized particle. Here we present a detailed biophysical study on the behavior of dynamic SCPNs in living cells and an evaluation of their catalytic functionality in such a complex medium. We first developed a number of delivery strategies that allowed the selective localization of SCPNs in different cellular compartments. Live/dead tests showed that the SCPNs were not toxic to cells while spectral imaging revealed that SCPNs provide a structural shielding and reduced the influence from the outer biological media. The ability of SCPNs to act as catalysts in biological media was first assessed by investigating their potential for reactive oxygen species generation. With porphyrins covalently attached to the SCPNs, singlet oxygen was generated upon irradiation with light, inducing spatially controlled cell death. In addition, Cu(I)- and Pd(II)-based SCPNs were prepared and these catalysts were screened in vitro and studied in cellular environments for the carbamate cleavage reaction of rhodamine-based substrates. This is a model reaction for the uncaging of bioactive compounds such as cytotoxic drugs for catalysis-based cancer therapy. We observed that the rate of the deprotection depends on both the organometallic catalysts and the nature of the protective group. The rate reduces from in vitro to the biological environment, indicating a strong influence of biomolecules on catalyst performance. The Cu(I)-based SCPNs in combination with the dimethylpropargyloxycarbonyl protective group showed the best performances both in vitro and in biological environment, making this group promising in biomedical applications

Diaphragmatic dysfunction in critically patients undergoing mechanical ventilation

Mechanical ventilation (MV) is an important cause of diaphragmatic weakness, associated with a syndrome known as ventilator Induced Diaphragmatic Disfunction (VIDD). The latter is determined by a heavy unload or overload of the diaphragm due to patient-ventilator asynchrony. It is important to minimize the duration of MV to optimize respiratory muscle function and to develop successful strategies that reduce the length of stay of ICU and days of MV. The primary endpoint of this project is to evaluate the ability of ultrasound in evaluating diaphragmatic contractility in relation to a possible diaphragm injury, as well as serum markers of muscle injury, during assisted MV. We will evaluate the relationship between diaphragmatic thickness and displacement with ventilator parameters (e.g. Eadi, Eadi max), titrate Neurally Adjusted Ventilator Assist (NAVA) level or PSV level assistance in order to improve ventilator trigger delay and synchrony, assessed by diaphragmatic ultrasonography