Various tissue-engineered vascular grafts have been studied in order to overcome the clinical disadvantages associated with conventional prostheses. However, previous tissue-engineered vascular grafts have possessed insufficient mechanical properties and thus have generally required either preoperative cellular manipulation or the use of bioreactors to improve their performance. In this study, we focused on the concept of in situ cellularization and developed a tissueengineered vascular graft with degradable/ non-degradable polymer composites for arterial reconstruction that would facilitate the renewal of autologous tissue without any pretreatment. Additionally, these composites are designed to improve the mechanical performance of a small-diameter vascular prosthesis scaffold that is made from a flexible membrane of poly(εcaprolactone) (PCL). The PCL scaffold was reinforced by embedding a tubular fabric that was knitted from polyethylene terephthalate (PET) yarns within the freeze-dried composite structure. Adding this knitted fabric component significantly improved the mechanical properties of the composite scaffold, such as its tensile strength and initial modulus, radial compliance, compression recovery, and suture retention force. Finally, this reinforced composite structure is a promising candidate for use as a tissue-engineered scaffold for a future small diameter vascular prosthesis.
The authors describe colorimetric test strips by using electrospun nanofiber membranes (NFMs) carrying gold/silver core/shell nanoparticles (Au/Ag NPs). The Au/Ag NPs were immobilized on aminated porous polyacrylonitrile NFMs to obtain test strips with a tortuous porous structure and a large surface area (38.6 m g). The color of the resultant NFMs, measured at a wavelength of 420 nm, is red-shifted when exposed to copper ions (Cu) with a color change from yellow to pink to colorless. The effect is due to leaching Au/Ag NPs from the NFMs in the presence of ammonium chloride, thiosulfate and Cu upon which soluble thiosulfate complexes of Ag, Au and Cu are formed. The effect can be readily seen with bare eyes. Under optimized conditions, this method has a low limit of detection (50 nM at S/N = 3), a fast assay time (3 min), good specificity, and excellent reversibility. The colorimetric test strip was successfully applied to the analysis of Cu in drinking water sample. Graphical abstract Schematic of the preparation of test strips for Cu by immobilizing Au/Ag core-shell nanoparticles on aminated polyacrylonitrile nanofibers.
Non-enzymatic colorimetric sensor strip for detection of metronidazole (MTZ) was designed and constructed, with high sensitivity and selectivity. Which can be used for naked-eye detection of MTZ with a visible color change from pink to purple.
Tetracycline (TC) is an inexpensive broad-spectrum antibiotic used to treat infectious diseases and to promote growth in animals. However, driven by economic interest, abuse of TC poses a serious threat to human beings, and it remains a significant challenge to create easy-to-use TC colorimetric test strips for public use. Herein, we present a strategy to prepare free-standing, nanofibrous structured test strips with tortuous porous structure and large surface area by combining polyacrylonitrile nanofibrous membranes (PAN NMs), alginate, and Fe3+. In this approach, alginate was first functionalized on the PAN NMs and then, Fe3+ was assembled into the alginate to construct a TC-sensing surface. The resultant test strips exhibited the following integrated properties: fast sensing process (10 min), low naked eye detection limit (5 μg kg-1), excellent anti-interference ability, and satisfactory reusability. Furthermore, the TC concentration-dependent color change (yellow to maroon) was quantitatively visualized by an iPhone read-out hue parameter. All the findings indicate that this intriguing approach may pave the way for versatile designing of NMs to serve as a preventive treatment for the public.
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