Photolithographically Patterned Cell-Repellent PEG-b-PTHPMA Diblock Copolymer for Guided Cell Adhesion and Growth

Surfaces for guided cell adhesion and growth are indispensable in several diagnostic and therapeutic applications. Towards this direction, four diblock copolymers comprising polyethylene glycol (PEG) and poly(2-tetrahydropyranyl methacrylate) (PTHPMA) are synthesized employing PEG macroinitiators of different chain lengths. The copolymer with a 5000 Da PEG block and a PEG-PTHPMA comonomers weight ratio of 43–57 provides a film with the highest stability in the culture medium and the strongest cell repellent properties. This copolymer is used to develop a positive photolithographic material and create stripe patterns onto silicon substrates. The highest selectivity regarding smooth muscle cell adhesion and growth and the highest fidelity of adhered cells for up to 3 days in culture is achieved for stripe patterns with widths between 25 and 27.5 µm. Smooth muscle cells cultured on such patterned substrates exhibit a decrease in their proliferation rate and nucleus area and an increase in their major axis length, compared to the cells cultured onto non-patterned substrates. These alterations are indicative of the adoption of a contractile rather than a synthetic phenotype of the smooth muscle cells grown onto the patterned substrates and demonstrate the potential of the novel photolithographic material and patterning method for guided cell adhesion and growth.     

SRv6-based Time-Sensitive Networks (TSN) with low-overhead rerouting

Time-Sensitive Networks (TSN) aims at providing a solid underpinning for the support of application connectivity demands across a wide spectrum of use cases and operational environments, such as industrial automation and automotive networks. However, handling network updates in TSN entails additional challenges, stemming from the need to perform both flow rerouting and TSN schedule reconfiguration. To address this issue, we propose a software-defined network (SDN)-based approach for low-overhead TSN network updates, exploiting segment routing over IPv6 (SRv6) for path control. To this end, we introduce the concept of TSN subgraphs in order to quickly reschedule the flows traversing the problematic area and propose a TSN-aware routing heuristic to minimize the convergence time. We further describe the control plane implementation and its integration into Mininet, which empowers us to conduct a wide range of performance tests. Our evaluation results indicate that our approach yields faster recovery and reduces significantly the number of required reconfigurations upon failures, at the expense of a small SRv6 encoding/decoding overhead.