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- Convection patterns gradients of non-living and living micro-entities in hydrogelsPublication . Canadas, Raphaël F.; Patricio, Pedro; Brancato, Virginia; Gasperini, Luca; Caballero, David; Pires, Ricardo A.; Costa, João; Pereira, Hélder; Yong, Ping; da Silva, Lucília P.; Chen, Jie; Kundu, Subhas C.; Araujo, Nuno; Reis, Rui L.; Marques, AP; Oliveira, Joaquim M.Inducing thermal gradients in two injected fluid systems results in the temporal formation of mixing conductive streams. If preserved through sol-gel transition, this mechanism can be used to drive and pattern non-living and living entities in mixed hydrogels. Interfaces are vital in nature, where gradients of non-living and living entities build distinct yet continuous integrated living tissues. However, the common tissue fabrication methodologies often result in dissimilar interfaces, lacking continuity through the interfaced engineered tissues. Thus, there is an urgent need for the fabrication of heterotypic but continuous engineered tissues with spatial control over biomimetic features. Here, we demonstrate the influence of gel injection temperature on the patterning of gradients of non-living and living entities. The experimental part was confirmed by numerical modelling, showing the formation of convective lines which spatially drive microscale microparticle and cells when different temperatures are applied in the sequential injection of two gels. Based on this finding, pure gellan gum (GG) and blended GG with methacrylated gelatin (Ge1MA) systems were used to program the formation of gradient features in hydrogels, such as microparticle and cells distribution patterns, polymeric bioactivity, degradation, controlled release, and stiffness. The correlation between gel injection temperature and gradients formation can be applied to tissue interface modelling, regeneration, drug release systems, and broader materials engineering fields.
- Gait cycle duration analysis in lower limb amputees using an IoT-based photonic wearable sensor: a preliminary proof-of-concept studyPublication . Alves, Bruna; Fantoni, Alessandro; Matos, José; Costa, João; Vieira, ManuelaThis study represents a preliminary proof of concept intended to demonstrate the feasibility of using a single-point LiDAR sensor for wearable gait analysis. The study presents a low-cost wearable sensor system that integrates a single-point LiDAR module and IoT connectivity to assess Gait Cycle Duration (GCD) and gait symmetry in real time. The device is positioned on the medial side of the calf to detect the contralateral limb crossing—used as a proxy for mid-stance—enabling the computation of GCD for both limbs and the derivation of the Symmetry Ratio and Symmetry Index. This was conducted under simulated walking at three cadences (slow, normal and fast). GCD estimated by the sensor was compared against the visual annotation with Kinovea®, showing reasonable agreement, with most cycle-wise relative differences below approximately 13% and both methods capturing similar symmetry trends. The wearable system operated reliably across different speeds, with an estimated materials cost of under 100 € and wireless data streaming to a cloud dashboard for real-time visualization. Although the validation is preliminary and limited to a single healthy participant and a video-based reference, the results support the feasibility of a photonic, IoT-based approach for portable and objective gait assessment, motivating future studies with larger and clinical cohorts and gold-standard references to quantify accuracy, repeatability and clinical utility.