Asymmetric wound dressings (AWD) are currently being developed to mimic the structural and functional characteristics of skin layers. To further enhance their performance, near-infrared (NIR) responsiveness has been explored to enable mild-temperature therapy, improve antibacterial properties, and control drug release. In this work, a NIR responsive AWD was developed by exploring a self-healing hydrogel based on oxidized hyaluronic acid (OHA, 2 % w/v), succinyl-chitosan (CS-SA, 2 % w/v) and polydopamine (PDA, 0.01 % w/v) nanoparticles with 250 nm, as a bottom layer, and a polycaprolactone (16 % w/v)/lignin (0, 2, or 3 % w/v) (PCL/LIG) electrospun membrane as top layer. The membrane provided a dense and randomly organized fibrous structure with slow degradation and hydrophobic character (water contact angle of 110 - 120 degrees), ensuring mechanical support and a protective barrier to the wound site. The hydrogel presented a self-healing behavior and PDA nanoparticles conferred photothermal capacity to the wound dressing, achieving a temperature increase of 12.2 +/- 0.2 degrees C after 10 min of NIR irradiation. Moreover, peppermint (Mentha & times; piperita) essential oil was incorporated into the hydrogel, further enhancing the antibacterial properties, and revealing a synergistic antibacterial effect under NIR exposure, with a bacterial viability of 18 % for Staphylococcus aureus and 29 % for Escherichia coli after 3 irradiations. Moreover, the in vitro data confirmed the cytocompatibility of both layers and the AWD with fibroblasts, even after one and three NIR laser irradiations. Overall, these results highlight the potential of NIR-responsive AWD to accelerate wound healing through combined structural, antibacterial, and photothermal effects.
Polyphenols exhibit a wide range of biological and pharmacological activities, yet their dermal delivery is often limited by skin permeability and formulation-dependent constraints. In this work, the potential of roller microneedling as a physical strategy to improve dermal delivery of representative polyphenols-epicatechin, epigallocatechin gallate (EGCG), and curcumin-was investigated using common topical dosage forms, namely polymeric gel, patch, and ointment. Standardized skin permeation parameters were first obtained using excised porcine skin under conditions of stratum corneum saturation. The microneedling procedure was characterized, and its effect on polyphenol transdermal permeation from each formulation type was evaluated using Franz diffusion cells. Maximum steady-state permeation fluxes varied from 13.2 mu g/cm2/h (curcumin) to 708 mu g/ cm2/h (epicatechin). Roller microneedling produced well-defined microchannels across the stratum corneum, with a mean interchannel distance of 2.3 mm, without compromising skin integrity, and significantly enhanced polyphenol permeation from all tested vehicles. Depending on the compound and formulation, microneedling increased permeation fluxes and/or reduced lag times, with particularly relevant effects observed for geldelivered curcumin and ointment-delivered EGCG. Moreover, the polyphenols exhibited a robust antioxidant activity (equivalent to micromolar ascorbic acid) after transdermal permeation, including following microneedle-assisted delivery, supporting the compatibility of microneedling and the formulation vehicles with polyphenol functionality. Overall enhancement factors were consistent, yielding approximately twofold increases in both permeation flux and antioxidant activity. These findings demonstrate that roller microneedling is a practical, low-invasive approach to enhance the dermal delivery of polyphenols from conventional topical formulations, offering a versatile strategy that complements formulation-based optimization for therapeutic and cosmetic applications.
Regarding the popularity of social media platforms among consumers, influencer marketing is increasingly present in brands' communication strategies. This study adds to the knowledge about the drivers of parasocial interactions with influencers by investigating not yet explored follower-influencer connections and their effects on consumers' responses to the recommended brands. An online consumer survey was conducted among followers of social media influencers and the data were analysed using partial least squares structural equation modelling (PLS-SEM). The results show that follower-influencer moral admiration, perceived similarity, emotional closeness, and expression of positive feelings positively affect their parasocial interaction. In turn, the effects of these variables on consumer responses are fully or partially mediated by follower-influencer parasocial interaction on social media networks. Interestingly, followers' skill admiration towards the influencer has no significant impact on parasocial interaction but has a positive significant direct impact on positive WOM and purchase intention of influencer recommend brands. Our findings demonstrate that influencer marketing communication is an effective strategy for improving consumer brand responses. Furthermore, to augment their marketing value, social media influencers need to promote parasocial interactions with followers. Our findings suggest novel recommendations to select influencers and manage influencer marketing value.
Additive manufacturing has been widely adopted in industry as an alternative to traditional manufacturing processes for complex component production. In fact, a diverse range of materials, particularly polymers, can be processed using 3D printing for biomechanical applications (e.g., prosthetics). However, in-depth evaluation of these materials is necessary to determine their suitability for demanding applications, such as those involving cyclic loading. Following previous work that studied Polylactic Acid (PLA) and Polyethylene Terephthalate Glycol-modified (PETG) under experimental fatigue testing, this study examines the fatigue behaviour of other current 3D-printed polymeric materials, namely Acrylonitrile Styrene Acrylate (ASA), Polycarbonate (PC), Polyamide 12 (Nylon 12), and Polycarbonate-Acrylonitrile Butadiene Styrene (blend) (PC-ABS), for which fatigue data remain limited or even non-existent. The findings revealed performance differences on Tensile Strength (σR), Young's Modulus and Ultimate Strain among tensile specimens made from these materials and characterised S-N curves for both high-cycle (HCF) and low-cycle (LCF) fatigue regimes at room temperature, with a tensile load ratio (R = 0.05). These results establish relationships among fatigue limit and quasi-static mechanical properties, namely 25% × σr for ASA (8 MPa), 7% × σr for PC (3.6 MPa), 17% × σr for Nylon 12 (7.4 MPa), and 15% × σr for PC-ABS (4.7 MPa), as well as between mechanical properties and preliminary potential biomechanical applications. Main conclusions were further supported by micro-computed tomography (micro-CT), which revealed levels of porosity in between 4% and 11%, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR).
Electrical stimulation (ES) has emerged as a promising therapeutic approach for enhancing chronic wound healing, addressing the limitations of conventional treatments such as high costs, prolonged recovery times, and suboptimal outcomes. However, traditional ES methods face challenges in delivering uniform stimulation across the wound area. Recent advances in electrospun-based wound dressings, particularly those combined with conductive polymers, offer a solution to these limitations. Conductive electrospun-based wound dressings mimic the skin's extracellular matrix, providing high porosity, a large surface area, and the capacity to deliver ES directly to the wound site, significantly enhancing therapeutic efficacy. This review provides a concise summary of the skin structure, the wound healing process and the effects of ES at various stages of healing. It also explores advanced electrospun-based wound dressings, focusing on the synergistic potential of combining ES with conductive electrospun dressings to optimize chronic wound healing outcomes.
