Lung tissue engineering: An update.

Pulmonary disease is a worldwide public health problem that reduces the life quality and increases the need for hospital admissions as well as the risk of premature death. A common problem is the significant shortage of lungs for transplantation as well as patients must also take immunosuppressive drugs for the rest of their lives to keep the immune system from attacking transplanted organs. Recently, a new strategy has been proposed in the cellular engineering of lung tissue as decellularization approaches. The main components for the lung tissue engineering are: (1) A suitable biological or synthetic three-dimensional (3D) scaffold, (2) source of stem cells or cells, (3) growth factors required to drive cell differentiation and proliferation, and (4) bioreactor, a system that supports a 3D composite biologically active. Although a number of synthetic as well biological 3D scaffold suggested for lung tissue engineering, the current favorite scaffold is decellularized extracellular matrix scaffold. There are a large number of commercial and academic made bioreactors, the favor has been, the one easy to sterilize, physiologically stimuli and support active cell growth as well as clinically translational. The challenges would be to develop a functional lung will depend on the endothelialized microvascular network and alveolar-capillary surface area to exchange gas. A critical review of the each components of lung tissue engineering is presented, following an appraisal of the literature in the last 5 years. This is a multibillion dollar industry and consider unmet clinical need.

Modified PLGA nanofibers as a nerve regenerator with Schwann cells.

Polylactide-co-glycolide acid (PLGA) is known as a biodegradable and biocompatible polymer. This polymer has been highly used in tissue engineering. In this study, the biological behavior of Schwann cells (Rat) was investigated in co-culture with L lysine/gelatine coated PLGA nano-fiber. In this study, PLGA was dissolved in a hexafluoro propanol based solvent and nanofiber prepared by an electronic method. They were coated with gelatin and poly-L-lysine individually. These polymer properties were investigated by Scanning Electron Microscopy (SEM) analysis and contact angle measurement. After extraction of rat Schwann cells, the cells were cultured in three groups of nano-fiber; nano-fiber PLGA, nano-fiber gelatine coated PLGA and nano-fiber poly-L-lysine coated PLGA. Cell death and Cell proliferation were evaluated by Acridine orange staining (living cell with a green nucleus and dead cell with an orange nucleus) and morphology was investigated by SEM in 2, 4 and 6 days. The diameter of electronic nanofiber PLGA was between 270 to 700 nm. Average contact angles of PLGA, PLGA coated with gelatine, coated with poly-L-lysine and PLGA were 40.12, 64.58 and 107.66degrees, respectively. The findings showed a significant reduction of cell proliferation in PLGA nanofiber ( it was important than PLGA without nano-fiber (P <0.05)). But, this amount was increased in nanofiber which coated with poly-L-lysine and gelatine. PLGA nanofiber-poly-L-lysine was more biocompatible than PLGA nanofiber-gelatine and this comparison was done with rat Schwann cells.

Smart fluorescence aptasensor using nanofiber functionalized with carbon quantum dot for specific detection of pathogenic bacteria in the wound.

We developed for the first time a novel and smart nanofiber (NF) network with the electrospinning method to create an amplified fluorescent biosensing platform for the detection of Staphylococcus aureus (S. aureus) bacteria in wound. The sensing platform is constructed based on surface modification of NFs by carbon quantum dots (CQDs) on the NF membrane surface, leading to large fluorescence signal amplification. CQDs synthesis was done from orto-phenylenediamine (OPD) with yellow emission fluorescence. Incorporation of CQDs leads to the uniform fluorescence of modified NFs. The proposed biosensing platform can also be applied to detect S. aureus bacteria with high sensitivity and selectivity via a specific aptamer. The linear sensing range for different S. aureus concentration from 10 to 108 CFU/mL and the detection limit of 10 CFU/mL was attained. For the first time these scaffolds were designed for the detection of specific pathogenic bacteria in wound using fluorescence signal of NFs, which can be seen by the naked eye under UV lamp. Enhancing in the fluorescence intensity after putting the modified NFs on skin wounds of mice for 2 h showed the successful application of this novel aptasensor.

Extraction and Characterization of Collagen with Cost-Effective Method from Human Placenta for Biomedical Applications.

BACKGROUND: Collagen is the main product in pharmaceutics and food industry with a high demand. Collagen can be extracted from several tissues such as skin, bone and tendon, etc. Collagen can be used in tissue engineering researches as a substrate of wound healing and nerve regeneration. Extraction methods of collagen are various with different purities. In this research, we aimed to extract collagen from human placenta with a modified method. METHODS: This modified approach was used for extracting of collagen from human placenta with acetic acid and NaCl treatment using different concentrations. RESULTS: SDS page showed three different bands that reflected two alpha-chains and one beta-chain with molecular weights of 102, 118 and 220 kDa, respectively. There was no significant difference between extracted collagen from human placenta and standard collagen in western blot analysis. CONCLUSION: It was concluded that human placenta can be an alternative source of collagen with high purity for biomedical applications such as tissue engineering, stem cell therapy and research.