Hyaluronic acid (HA) is an endogenous polysaccharide, whose hydrogels have been used in medical applications for decades. Here, we present a technology platform for stabilizing HA with a biocrosslinker, the amino acid L-lysine, to manufacture bionic hydrogels for regenerative medicine. We synthetized bionic hydrogels with tailored composition with respect to HA concentration and degree of stabilization depending on the envisaged medical use. The structure of the hydrogels was assessed by microscopy and rheology, and the resorption behavior through enzymatic degradation with hyaluronidase. The biological compatibility was evaluated in vitro with human dermal fibroblast cell lines. HA bionic hydrogels stabilized with lysine show a 3D network structure, with a rheological profile that mimics biological matrixes, as a harmless biodegradable substrate for cell proliferation and regeneration and a promising candidate for wound healing and other medical applications.

(1) Background: Acne is a widespread skin disease, especially among adolescents. Following the COVID-19 pandemic and the use of masks, the problem has been affecting a greater number of people, and the attention of the skin care beauty routine cosmetics has been focused on the “Maskne”, caused by the sebum excretion rate (SER) that stimulates microbial proliferation. (2) Methods: the present study was focused on the rheological characterization and quality assurance of the preservative system of an anti-acne serum. The biological effectiveness (cytotoxicity—skin and eye irritation—antimicrobial, biofilm eradication and anti-inflammatory activity) was evaluated in a monolayer cell line of keratinocytes (HaCaT) and on 3D models (reconstructed human epidermis, RHE and human reconstructed corneal epithelium, HCE). The Cutibacterium acnes, as the most relevant acne-inducing bacterium, is chosen as a pro-inflammatory stimulus and to evaluate the antimicrobial activity of the serum. (3) Results and Conclusions: Rheology allows to simulate serum behavior at rest, extrusion and application, so the serum could be defined as having a solid-like behavior and being pseudoplastic. The preservative system is in compliance with the criteria of the reference standard. Biological effectiveness evaluation shows non-cytotoxic and irritant behavior with a good antimicrobial and anti-inflammatory activity of the formulation, supporting the effectiveness of the serum for acne-prone skin treatment.

Physiological ageing due to the passing of time and prolonged exposure to harmful sun rays generate wrinkles and reduce skin elasticity. These visible and clinical signs can be prevented or reversed by known strategies, such as the daily use of cosmetic products with antioxidant combinations or retinoids. A new dermocosmetic formulation enriched with a complex of retinoids, called RETINOIDS SERUM, was investigated through in vitro assays using human skin cells. The experiments were carried out to assess the anti-ageing activity in normal human dermal fibroblasts (NHDF) and epidermal keratinocytes (HaCaT). After the preliminary MTT assay, the proliferation together with the synthesis of collagen and elastin fibers was performed on NHDF cells after 24 h treatment with the two non-cytotoxic concentrations. Using UVB-irradiated HaCaT cells, the measurement of matrix metalloproteinase-1 (MMP-1) levels was also investigated. In vitro studies show that the dermocosmetic product improves collagen and elastin synthesis and the renewal of dermal fibroblasts. Moreover, a reduction in the MMP-1 secretion was also highlighted in UVB-irradiated HaCaT cells. These results suggest that the cosmetic formulation containing functional compounds such as retinoids can be useful to prevent the natural sign of ageing.

(1) Background: The dysbiosis of some cutaneous commensal microorganisms is the trigger factor for the activation of the inflammatory cascade by keratinocytes in many skin disorders. Mesotherapy is an innovative technique for many scalp disorders, with the function of restoring the physiology of the skin. (2) Methods: the antimicrobial, antibiofilm and anti-inflammatory activity of the non-cross-linked HA formulation (Hydro Deluxe, Matex Lab S.p.a., Brindisi, Italy) was investigated against the most common microorganisms of the scalp (Staphyloccoccus epidermis, Staphyloccoccus aureus, Cutibacterium acnes and Malassezia furfur). Anti-inflammatory activity was evaluated on an internal 3D model of Reconstructed Human Epidermis (RHE) inserts infected with the strains as pro-inflammatory stimulus. (3) Results and Conclusions: the data collected showed a good antimicrobial and antibiofilm activity against all selected strains. The HA-based formulation did not show cytotoxicity on RHE, either alone or in presence of the infectious stimulus. The analysis of the expression of Interleukin (IL)-8 levels showed an excellent ability to reduce this pro-inflammatory marker. Overall, the efficacy assessment of the formulation supported its potential effectiveness in mesotherapy for the treatment of scalp disorders.