Background: Nanoparticles are widely used in different technological fields, one of which is medicine. Because of their antibacterial properties, silver nanoparticles (AgNPs) are used in several types of wound dressings for the treatment of burns and nonhealing wounds, but their influence on each component of the wound-healing process remains unclear. In the present study, we evaluated the effects of AgNPs on normal human dermal fibroblasts (NHDFs) and normal human epidermal keratinocytes (NHEKs). Both cell types are important for wound healing, including with regard to inflammation, proliferation and tissue remodeling. Each phase of wound healing can be characterized by the secretion of cytokines, chemokines and growth factors. Methods: The production of inflammatory parameters (tumor necrosis factor α [TNF-α], interleukin-6 [IL-6], IL-8 and IL-12 and cyclooxygenase-2 [COX-2]), angiogenesis parameters (vascular endothelial growth factor [VEGF], granulocyte macrophage colony-stimulating factor) and matrix metalloproteinases (MMP-1, MMP-2, MMP-3 and MMP-9) by NHDFs and NHEKs were examined by ELISA or Western blot after 24 and 48 hours of incubation with AgNPs. Results: We found that AgNPs decreased some inflammatory cytokines (TNF-α and IL-12) and growth factors (VEGF) that were produced by NHDFs and NHEKs after 24 and 48 hours and decreased the expression of COX-2 after 24 hours but only at the highest concentration of AgNPs (25 parts per million). Conclusions: The results indicate that NHEKs are more susceptible to the application of AgNPs than NHDFs, and AgNPs may be useful for medical applications for the treatment of wounds.

Biomedical application of silver nanoparticles (AgNPs) has been rapidly increasing. Owing to their strong antimicrobial activity, AgNPs are used in dermatology in the treatment of wounds and burns. However, recent evidence for their cytotoxicity gives rise to safety concerns. This study was undertaken as a part of an ongoing programme in our laboratory to develop a topical agent for wound healing. Here, we investigated the potential toxicity of AgNPs using normal human dermal fibroblasts (NHDF) and normal human epidermal keratinocytes (NHEK) with the aim of comparing the effects of AgNPs and ionic silver (Ag-I). Besides the effect of AgNPs and Ag-I on cell viability, the inflammatory response and DNA damage in AgNPs and Ag-I–treated cells were examined. The results showed that Ag-I were significantly more toxic than AgNPs both on NHDF and NHEK. Non-cytotoxic concentrations of AgNPs and Ag-I did not induce DNA strand breaks and did not affect inflammatory markers, except for a transient increase in interleukin 6 levels in Ag-I–treated NHDF. The results showed that AgNPs are more suitable for the intended application as a topical agent for wound healing up to the concentration 25 µg/mL.

The cornea and the skin are two organs that form the outer barrier of the human body. When either is injured (e.g., from surgery, physical trauma, or chemical burns), wound healing is initiated to restore integrity. Many cells are activated during wound healing. In particular, fibroblasts that are stimulated often transition into repair fibroblasts or myofibroblasts that synthesize extracellular matrix (ECM) components into the wound area. Control of wound ECM deposition is critical, as a disorganized ECM can block restoration of function. One of the most abundant structural proteins in the mammalian ECM is collagen. Collagen type I is the main component in connective tissues. It can be readily obtained and purified, and short analogs have also been developed for tissue engineering applications, including modulating the wound healing response. This review discusses the effect of several current collagen implants on the stimulation of corneal and skin wound healing. These range from collagen sponges and hydrogels to films and membranes.

Recently, due to their unique properties, gold nanoparticles (AuNPs) have been used in many biological applications. However, little is known about their toxicity when they come into contact with a biological system. Based on the proposal that AuNPs can have a positive effect on wound healing, the present study investigated the influence of negatively-charged-surface AuNPs (average diameter 25–50 nm) on the viability of normal human dermal fibroblasts (NHDF) and normal human epidermal keratinocytes (NHEK). Moreover, we evaluated the effect of AuNPs on the secretion of proteins involved in wound healing, such as interleukin-8 and – 12 (IL-8, IL-12), tumour necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), basic fibroblast grow factor (bFGF), and granulocyte-macrophage colony-stimulating factor (GM-CSF). The results showed that AuNPs were not toxic to NHDF and NHEK. They showed a decrease in AuNPs' production of pro-inflammatory cytokines IL-6, IL-12 and TNF-α, as well as proteins involved in angiogenesis such as VEGF and bFGF. Thus, we suggest that AuNPs could have anti-inflammatory and anti-angiogenic activity.

The epidermis is the external layer of the skin and is composed mainly of keratinocytes. Therefore, keratinocytes play an indispensable role as inherent constituents of the skin barrier in physical defenses against environmental threats. Keratinocytes also exert an active protective role against invasion by pathogens. This competency is of particular importance when physical defenses fail as a consequence of skin injury. During the inflammatory phase of healing, keratinocytes act as immuno-modulators, managing inflammation via a rigorously coordinated network of inflammatory cascades, triggered by keratinocyte-receptor communication with the surroundings in a paracrine and autocrine manner. This review summarizes current understandings of the coordinated inflammatory network and focuses on recent progress regarding the role of keratinocytes in early phases of skin wound healing.

Aging is a complex physiological process that can be accelerated by chemical (high blood glucose levels) or physical (solar exposure) factors. It is accompanied by the accumulation of altered molecules in the human body. The accumulation of oxidatively modified and glycated proteins is associated with inflammation and the progression of chronic diseases (aging). The use of antiglycating agents is one of the recent approaches in the preventive strategy of aging and natural compounds seem to be promising candidates. Our study focused on the anti-aging effect of the flavonoid hesperetin, its glycoside hesperidin and its carbohydrate moieties rutinose and rhamnose on young and physiologically aged normal human dermal fibroblasts (NHDFs). The anti-aging activity of the test compounds was evaluated by measuring matrix metalloproteinases (MMPs) and inflammatory interleukins by ELISA. The modulation of elastase, hyaluronidase, and collagenase activity by the tested substances was evaluated spectrophotometrically by tube tests. Rutinose and rhamnose inhibited the activity of pure elastase, hyaluronidase, and collagenase. Hesperidin and hesperetin inhibited elastase and hyaluronidase activity. In skin aging models, MMP-1 and MMP-2 levels were reduced after application of all tested substances. Collagen I production was increased after the application of rhamnose and rutinose.