Material and mechanical factors:new strategy in cellular neurogenesis

Since damaged neural circuits are not generally self-recovered, developing methods to stimulate neurogenesis is critically required. Most studies have examined the effects of soluble pharma- cological factors on the cellular neurogenesis. On the other hand, it is now recognized that the other extracellular factors, including material and mechanical cues, also have a strong potential to induce cellular neurogenesis. This article will review recent data on the material （chemical patterning, micro/nano-topography, carbon nanotube, graphene） and mechanical （static cue from substrate stiffness, dynamic cue from stretch and flow shear） stimulations of cellular neuro- genesis. These approaches may provide new neural regenerative medicine protocols. Scaffolding material templates capable of triggering cellular neurogenesis can be explored in the presence of neurogenesis-stimulatory mechanical environments, and also with conventional soluble factors, to enhance axonal growth and neural network formation in neural tissue engineering.

Quantitative detection of citrate for early stage diagnosing of prostate cancer:Discriminating normal to cancer in prostate tissues

Prostate cancer(PC)biomarker-citrate detection is clinically important to diagnose PC in early stages.Methylquinolinium iodide(Q)conjugated indole-phenylboronic acid(IB)was designed as a red-emissive QIB probe for the detection of citrate through Lewis acid-base reaction and intramolecular charge transfer(ICT)sensing mechanisms.Boronic acid acts as Lewis acid as well as citrate(Lewis base)recognition unit.The probe reacted with citrate,showing enhanced red emissions.Since the probe has excellent water solubility and great biocompatibility,practical application in biological systems is possible.Citrate was monitored precisely in the mitochondria organelle(in vitro)of living cells with a positive charge on QIB.Also,endogenous(in situ)citrate was detected quantitatively to discriminate non-cancerous and PC mice,observed strong and lower(negligible)emission intensity on non-cancerous and cancerous prostate tissues,respectively.Because,the concentration of citrate is higher in healthy prostate compared with PC prostate.Furthermore,the analysis of sliced prostate tissues can give PC-related information for clinical diagnosis to prevent and treat PC in the initial stages.Therefore,we believe that the present probe is a promising biochemical reagent in diagnosing PC.

Degradable and Tunable Keratin-fibrinogen Hydrogel as Controlled Release System for Skin Tissue Regeneration

Biodegradable hydrogels are promising biomaterials for use in controlled-release systems for skin tissue regeneration. Controlled delivery systems constitute an important aspect of tissue engineering because they can modulate various physiological responses, including early immune response, tissue remodeling, and cell proliferation and maturation in the wound-healing process. Hydrogels composed of various biomaterials have been developed to overcome the limitations of conventional drug- or protein-delivery systems, such as limited targeting ability, low stability, and the induction of drug resistance. Hydrogels based on keratin, a natural polymer extracted from human hair, can provide adequate cell support and control homeostasis. Consequently, they can be applied for skin tissue engineering. In this study, we prepared degradable, tunable, and biocompatible hydrogels for controllable protein delivery. We synthesized keratin-fibrinogen (KER-FBG) by the chemical coupling reaction and prepared hydrogels through polymerization with thrombin. The structures and morphologies of the KER-FBG hydrogels were confirmed. Furthermore, the mechanical properties, swelling ratio, degradation, release behavior, and biocompatibility were investigated. The KER-FBG hydrogels presented promising biological performance, indicating that the material is suitable as a controlled protein delivery carrier.

Fabrication of 3D Printed PCL/PEG Polyblend Scaffold Using Rapid Prototyping System for Bone Tissue Engineering Application

Three-dimensional （3D） printing is a novel process used to manufacture bone tissue engineered scaffolds. This process allows for easy control of the architecture at the micro structure. However, the scaffold properties are typically limited in terms of cellular activity at the scaffold surface due to the printed materials properties. In this study, we developed a polycaprolactone （PCL） blended with polyethylene glycol （PEG） 3D printed scaffold using a rapid prototyping system. The manufactured scaffolds were then washed out to form small pores on the surface in order to improve the scaffolds hydrophilicity. We analyzed the resultant material by using Scanning Electron Microscopy （SEM）, water absorption, water contact angle, in vitro WST-1, and the Bradford assay. Additionally, cells incubated on the fabricated scaffolds were visualized by Confocal Laser Scanning Microscopy （CLSM）. The developed scaffolds exhibited small pores on the strand surface which served to increase hydrophilicity as well as improve cellular proliferation and increase total protein content. Our findings suggest that the presence of small pores on the scaffolds can be used as an effective tool for improving implant cellular interaction. This research indicates that these modified scaffolds can be considered useful for bone tissue engineering applications to improve human health.