Honey is a natural sweetener that is derived from the nectar, pollen, and resin of plants. It has been used as a folk medicine for decades. In addition to being an excellent therapeutic agent, honey possesses an unusually high nutritional content, thus generating interest among researchers. The major phytonutrients of honey are polyphenols. Polyphenols can be separated using high-performance liquid chromatography (HPLC) or liquid chromatography-mass spectrometry (LC-MS). Moreover, to separate the volatile compounds in honey, gas chromatography-mass spectrometry (GC-MS) may be used. Polyphenols have unique and complex structures that are mainly composed of flavonoids and phenolic acids, which confer significant antiviral, anti-inflammatory, antineoplastic, and antiulcer effects and can be used to treat chronic diseases, such as cardiovascular disease. The nature and variability of polyphenols in different honeys posed a challenge to investigations in previous years. Nevertheless, the significant role of honey as a natural therapy and its enrichment with natural substances have led to the continuous discovery of efficient, reliable, and rapid methods for the identification and quantification of novel bioactive compounds in honey. This current review highlights the above mentioned issues.

Tissue engineering essentially refers to technology for growing new human tissue and is distinct from regenerative medicine. Currently, pieces of skin are already being fabricated for clinical use and many other tissue types may be fabricated in the future. Tissue engineering was first defined in 1987 by the United States National Science Foundation which critically discussed the future targets of bioengineering research and its consequences. The principles of tissue engineering are to initiate cell cultures in vitro, grow them on scaffolds in situ and transplant the composite into a recipient in vivo. From the beginning, scaffolds have been necessary in tissue engineering applications. Regardless, the latest technology has redirected established approaches by omitting scaffolds. Currently, scientists from diverse research institutes are engineering skin without scaffolds. Due to their advantageous properties, stem cells have robustly transformed the tissue engineering field as part of an engineered bilayered skin substitute that will later be discussed in detail. Additionally, utilizing biomaterials or skin replacement products in skin tissue engineering as strategy to successfully direct cell proliferation and differentiation as well as to optimize the safety of handling during grafting is beneficial. This approach has also led to the cells' application in developing the novel skin substitute that will be briefly explained in this review.

Wounds with full-thickness skin loss are commonly managed by skin grafting. In the absence of a graft, reepithelialization is imperfect and leads to increased scar formation. Biomaterials can alter wound healing so that it produces more regenerative tissue and fewer scars. This current study use the new chitosan based biomaterial in full-thickness wound with impaired healing on rat model. Wounds were evaluated after being treated with a chitosan dermal substitute, a chitosan skin substitute, or duoderm CGF. Wounds treated with the chitosan skin substitute showed the most re-epithelialization (33.2 ± 2.8%), longest epithelial tongue (1.62 ± 0.13 mm), and shortest migratory tongue distance (7.11 ± 0.25 mm). The scar size of wounds treated with the chitosan dermal substitute (0.13 ± 0.02 cm) and chitosan skin substitute (0.16 ± 0.05 cm) were significantly decreased (P < 0.05) compared with duoderm (0.45 ± 0.11 cm). Human leukocyte antigen (HLA) expression on days 7, 14, and 21 revealed the presence of human hair follicle stem cells and fibroblasts that were incorporated into and surviving in the irradiated wound. We have proven that a chitosan dermal substitute and chitosan skin substitute are suitable for wound healing in full-thickness wounds that are impaired due to radiation.

The challenge arises among researchers when hair follicle stem cells (HFSCs) derived from a human hair follicle remain poorly expanded in defined culture medium. In this study, we isolated the HFSCs and they became confluent after 10 days of cultivation. Comparing the viability of HFSCs cultured in defined keratinocytes serum free medium (KSFM) in a coated plate and CnT07 medium in an uncoated plate, the number of HFSCs cultured in CnT07 was significantly higher at days 2, 4, 6 and 8 (P=0.004). The population doubling time of HFSCs was 21.48±0.44 hours in non-coated plates with CnT07 and 30.73±0.75 hours in coated plates with KSFM. Our primary HFSC cultures were positive for CD200 and K15 with brownish color. Flow cytometry analysis showed that the percentage of HFSCs expressing CD200 and K15 were 65.20±3.16 and 72.07±6.62 respectively. After reaching 100% confluence, the HFSCs were differentiated into an epidermal layer in vitro using CnT02-3D defined media. HFSCs were differentiated into an epidermal layer after 2 weeks of induction. Involucrin- and K6-positive cells were detected in the differentiated epidermal layer. This method is a simple technique for HFSC isolation and has a lower cost of processing and labor, and it represents a promising tool for skin tissue engineering.

Chitosan is a marine-derived product that has been widely used in clinical applications, especially in skin reconstruction. The mammalian scaffolds derived from bovine and porcine material have many limitations, for example, prion transmission and religious concerns. Therefore, we created a chitosan skin regenerating template (SRT) and investigated the behavior of fibroblast cell-scaffold constructs. Primary human dermal fibroblasts (HDF) were isolated and then characterized using vimentin and versican. HDF were seeded into chitosan SRT at a density of 3×106 cells/cm2 for fourteen days. Histological analysis and live cells imaging revealed that the cell-chitosan constructs within interconnected porous chitosan showed significant interaction between the cells as well as between the cells and the chitosan. Scanning electron microscopy (SEM) analysis revealed cells spreading and covering the pores. As the pore sizes of the chitosan SRT range between 40–140 μm, an average porosity is about 93 ± 12.57% and water uptake ratio of chitosan SRT is 536.02 ± 14.29%, it is a supportive template for fibroblast attachment and has potential in applications as a dermal substitute.