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Tissue engineering endeavors to regenerate tissues and organs through appropriate cellular and molecular interactions at biological interfaces. To this aim, bio-mimicking scaffolds have been designed and practiced to regenerate and repair dysfunctional tissues by modifying cellular activity. Cellular activity and intracellular signaling are performances given to a tissue as a result of the function of elaborated electrically conductive materials. In some cases, conductive materials have exhibited antibacterial properties; moreover, such materials can be utilized for on-demand drug release. Various types of materials ranging from polymers to ceramics and metals have been utilized as parts of conductive tissue engineering scaffolds, having conductivity assortments from a range of semi-conductive to conductive. The cellular and molecular activity can also be affected by the microstructure; therefore, the fabrication methods should be evaluated along with an appropriate selection of conductive materials. This review aims to address the research progress toward the use of electrically conductive materials for the modulation of cellular response at the material-tissue interface for tissue engineering applications.

We introduce a theoretical model based upon the kinetic Monte Carlo (KMC) simulation approach capable of quantifying chain shuttling copolymerization (CSP) of ethylene and 1-octene in a semibatch operation. To make a deeper understanding of kinetics and evolution of microstructure, the reversible transfer reaction is first investigated by applying each of the individual catalysts to the reaction media, and the competences and shortcomings of a qualified set of CSP catalysts are discussed based on coordinative chain transfer copolymerization (CCTP) requirements. A detailed simulation study is also provided, which reflects and compares the contributions of chain transfer reversibility and other chain breaking reactions in controlling distribution fashion of molecular weight and chemical composition. The developed computer code is executed to capture developments in dead chain concentration and time-driven composition drift during CCTP. Also, the effect of chain shuttling agent (CSA) on the copolymerization kinetics is theoretically studied by simultaneous activation of both catalysts. In this way, it is attempted to make control over comonomer incorporation in the course of copolymerization. The molecular-level criteria reflecting copolymer properties, i.e., ethylene sequence length distribution and longest ethylene sequence length, as the signature of CSA performance, are virtually simulated in the presence and absence of hydrogen to capture an image on gradient copolymers in CCTP and blocks with gradually changing composition in CSP.

Flame Retardancy Index, FRI, was defined as a simple yet universal dimensionless criterion born out of cone calorimetry data on thermoplastic composites and then put into practice for quantifying the flame retardancy performance of different polymer composites on a set of reliable data. Four types of thermoplastic composites filled with a wide variety of flame retardant additives were chosen for making comparative evaluations regardless of the type and loading level of the additive as well as the irradiance flux. The main features of cone calorimetry including peak of Heat Release Rate (pHRR), Total Heat Release (THR), and Time-To-Ignition (TTI) served to calculate a dimensionless measure that reflects an improvement in the flame retardancy of nominated thermoplastic composites with respect to the neat thermoplastic, quantitatively. A meaningful trend was observed among well-classified ranges of FRI quantities calculated for the studied dataset on thermoplastic composites by which “Poor”, “Good”, and “Excellent” flame retardancy performances were explicitly defined and exhibited on logarithmic scales of FRI axis. The proposed index remains adaptable to thermoplastic systems whatever the polymer or additive is.