PleurAlert: an augmented chest drainage system with electronic sensing, automated alerts and internet connectivity.

We have enhanced a common medical device, the chest tube drainage container, with electronic sensing of fluid volume, automated detection of critical alarm conditions and the ability to automatically send alert text messages to a nurse's cell phone. The PleurAlert system provides a simple touch-screen interface and can graphically display chest tube output over time. Our design augments a device whose basic function dates back 50 years by adding technology to automate and optimize a monitoring process that can be time consuming and inconvenient for nurses.

Extended and sequential delivery of protein from injectable thermoresponsive hydrogels.

Thermoresponsive hydrogels are attractive for their injectability and retention in tissue sites where they may serve as a mechanical support and as a scaffold to guide tissue remodeling. Our objective in this report was to develop a thermoresponsive, biodegradable hydrogel system that would be capable of protein release from two distinct reservoirs--one where protein was attached to the hydrogel backbone, and one where protein was loaded into biodegradable microparticles mixed into the network. Thermoresponsive hydrogels consisting of N-isopropylacrylamide (NIPAAm), 2-hydroxyethyl methacrylate (HEMA), and biodegradable methacrylate polylactide were synthesized along with modified copolymers incorporating 1 mol % protein-reactive methacryloxy N-hydroxysuccinimide (MANHS), hydrophilic acrylic acid (AAc), or both.

Biodegradable polyurethane ureas with variable polyester or polycarbonate soft segments: effects of crystallinity, molecular weight, and composition on mechanical properties.

Biodegradable polyurethane urea (PUU) elastomers are ideal candidates for fabricating tissue engineering scaffolds with mechanical properties akin to strong and resilient soft tissues. PUU with a crystalline poly(ε-caprolactone) (PCL) macrodiol soft segment (SS) showed good elasticity and resilience at small strains (<50%) but showed poor resilience under large strains because of stress-induced crystallization of the PCL segments, with a permanent set of 677 ± 30% after tensile failure. To obtain softer and more resilient PUUs, we used noncrystalline poly(trimethylene carbonate) (PTMC) or poly(δ-valerolactone-co-ε-caprolactone) (PVLCL) macrodiols of different molecular weights as SSs that were reacted with 1,4-diisocyanatobutane and chain extended with 1,4-diaminobutane.

Spatial control of gene expression within a scaffold by localized inducer release.

Gene expression can be controlled in genetically modified cells by employing an inducer/promoter system where presence of the inducer molecule regulates the timing and level of gene expression. By applying the principles of controlled release, it should be possible to control gene expression on a biomaterial surface by the presence or absence of inducer release from the underlying material matrix, thus avoiding alternative techniques that rely upon uptake of relatively labile DNA from material surfaces. To evaluate this concept, a modified ecdysone-responsive gene expression system was transfected into B16 murine cells and the ability of an inducer ligand, which was released from elastomeric poly(ester urethane) urea (PEUU), to initiate gene expression was studied.