We demonstrate a novel structure based on smart carbon nanocomposites intended for fabricating laser-triggered drug delivery devices (DDDs). The performance of the devices relies on nanocomposites’ photothermal effects that are based on polydimethylsiloxane (PDMS) with carbon nanoparticles (CNPs). Upon evaluating the main features of the nanocomposites through physicochemical and photomechanical characterizations, we identified the main photomechanical features to be considered for selecting a nanocomposite for the DDDs. The capabilities of the PDMS/CNPs prototypes for drug delivery were tested using rhodamine-B (Rh-B) as a marker solution, allowing for visualizing and quantifying the release of the marker contained within the device. Our results showed that the DDDs readily expel the Rh-B from the reservoir upon laser irradiation and the amount of released Rh-B depends on the exposure time. Additionally, we identified two main Rh-B release mechanisms, the first one is based on the device elastic deformation and the second one is based on bubble generation and its expansion into the device. Both mechanisms were further elucidated through numerical simulations and compared with the experimental results. These promising results demonstrate that an inexpensive nanocomposite such as PDMS/CNPs can serve as a foundation for novel DDDs with spatial and temporal release control through laser irradiation.

We demonstrated that the combination of poly(dimethylsiloxane) (PDMS) and a hybrid hydrogel based on chitosan/poly(vinyl alcohol)/genipin (CS/PVA/GEN)—with ratios 7:3 (SIPNs1), 5:5 (SIPNs2), and 3:7 (SIPNs3) (w/w)—were useful for obtaining semi-interpenetrated polymeric networks (SIPNs). These SIPNs successfully combined the PDMS’s elasticity, the PVA’s swelling capability, and the excellent biological response of CS and GEN. Noticing these features are desirable in materials intended for biomedical applications such as wound healing and tissue engineering. Through evaluating the influence of PDMS and CS/PVA/GEN hybrid hydrogel ratios on the physico-chemical, mechanical, and the response of seeded cells, we found contact angles between 55 $$^{\circ }$$∘ and 75 $$^{\circ }$$∘ , while the swelling percentage was enhanced up to three times concerning blank PDMS. Besides, the elastic moduli presented values between 1 and 1.6 MPa. The fibroblasts seeded on the tested semi-interpenetrating polymeric networks were viable, and no cytotoxic effects were found. The cells presented fusiform shapes indicating an excellent attachment to the material’s surface. The highest cell densities were found for SIPNs1 and SIPNs2, suggesting that these compositions in a membrane shape could potentially be used in wound healing/dressing or as a scaffold for tissue engineering. Graphical

The development of injectable hydrogels with natural biopolymers such as gelatin (Ge) and hyaluronic acid (Ha) is widely performed due to their biocompatibility and biodegradability. The combination of both polymers crosslinked with N-Ethyl-N′-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) can be used as an innovative dermal filler that stimulates fibroblast activity and increases skin elasticity and tightness. Thus, crosslinked Ge/Ha hydrogels with different concentrations of EDC were administered subcutaneously to test their efficacy in young and old rats. At higher EDC concentrations, the viscosity decreases while the particle size of the hydrogels increases. At all concentrations of EDC, amino and carboxyl groups are present. The histological analysis shows an acute inflammatory response, which disappears seven days after application. At one and three months post-treatment, no remains of the hydrogels are found, and the number of fibroblasts increases in all groups in comparison with the control. In addition, the elastic modulus of the skin increases after three months of treatment. Because EDC-crosslinked Ge/Ha hydrogels are biocompatible and induce increased skin tension, fibroblast proliferation, and de novo extracellular matrix production, we propose their use as a treatment to attenuate wrinkles and expression lines.

Traditional tools for assessing burns, such as the Vancouver Scar Scale and Cutometry, provide only subjective or localized mechanical evaluations. These methods lack the capacity to deliver comprehensive, objective data on skin deformation, particularly during dynamic movement. This study aims to demonstrate the utility of 3D-Digital Image Correlation (3D-DIC) as a non-invasive, quantitative technique for capturing full-field strain and displacement responses of the skin throughout the complete articular range of motion of the distal upper extremity. An in vivo experimental protocol was applied to a healthy subject to evaluate the mechanical behavior of the skin on the dorsal hand and volar forearm. 3D-DIC was used to quantify strain and displacement during metacarpophalangeal flexion (MF), composite fist (CF), wrist flexion (WF), and wrist extension (WE). Cutometry was also applied on volar and dorsal regions of the forearm to obtain comparative strain profiles under localized suction. 3D-DIC revealed semicircular skin recruitment patterns. Maximum displacements of 9 mm and 11 mm were observed for MF and CF, respectively, with corresponding maximum strains of 30 % and 35 %. During WF and WE, displacements ranged from 10-12 mm, with the highest strain localized near the radiocarpal joint. While Cutometry and 3D-DIC yielded different strain behaviors, the two methods proved complementary, enhancing the understanding of skin deformation under different mechanical stimuli. These findings suggest that 3D-DIC can serve as a robust, objective tool for evaluating skin mechanics in clinical and research settings, especially for applications involving scar assessment, surgical planning, and rehabilitation monitoring.