This review focuses on the challenges associated with the design and development of injectable hydrogels of synthetic origin based on FDA approved blocks, such as polyethylene glycol (PEG) and poly(ɛ-caprolactone) (PCL). An overview of recent studies on inverse thermosensitive PEG/PCL hydrogels is provided. These systems have been proposed to overcome the limitations of previously introduced degradable thermosensitive hydrogels [e.g., PEG/poly(lactide-co-glycolic acid) hydrogels]. PEG/PCL hydrogels are advantageous due to their higher gel strength, slower degradation rate and availability in powder form. Particularly, triblock PEG/PCL copolymers have been widely investigated, with PCL-PEG-PCL (PCEC) hydrogels showing superior gel strength and slower degradation kinetics than PEG-PCL-PEG (PECE) hydrogels. Compared to triblock PEG/PCL copolymers, concentrated solutions of multiblock PEG/PCL copolymers were stable due to their slower crystallization rate. However, the resulting hydrogel gel strength was low. Inverse thermosensitive triblock PEG/PCL hydrogels have been mainly applied in tissue engineering, to decrease tissue adherence or, in combination with bioactive molecules, to promote tissue regeneration. They have also found application as in situ drug delivery carriers. On the other hand, the wide potentialities of multiblock PEG/PCL hydrogels, associated with the stability of their water-based solutions under storage, their higher degradation time compared to triblock copolymer hydrogels and the possibility to insert bioactive building blocks along the copolymer chains, have not been fully exploited yet. A critical discussion is provided to highlight advantages and limitations of currently developed themosensitive PEG/PCL hydrogels, suggesting future strategies for the realization of PEG/PCL-based copolymers with improved performance in the different application fields.

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The proposed paper is about the development of an integrated manufacturing process for smart 3D polymeric components, with electronics embedded, developed in the framework of research collaboration between the university partner and a group of SME. The system will be able to produce a polymeric structure by additive manufacturing technique, whereas a robotic system is integrated in the line to assemble electronic components onto the part while the manufacturing process goes on. A laser engraving station will process the component, providing micro- and nano-surface structuring, microcutting and microdrilling. Finally, another laser source is integrated in the system to weld electronic parts and circuits within the manufactured component. At the same time, the assembly of large size systems by welding small size components is allowed, and also a sealed atmosphere is ensured by welding a plastic cap onto the plastic structure.