In this paper, polyacrylonitrile (PAN) nanofibrous membranes (NFMs) were prepared by electrospinning technology. Copper (Cu) or/and zinc (Zn) nanoparticles (NPs) were deposited on the surface of PAN NFMs by spark ablation technology to fabricate a surface structure with antibacterial and hydrophobic properties. The deposition of NPs was controlled using current, voltage, carrier gas flow rate, and load time. The fabricated NFMs were characterized by FE-SEM, EDX, XRD, and water contact angle. Moreover, the antibacterial properties of the fabricated NFMs were studied using the agar-diffusion test method. The results showed that Cu, or/and Zn NPs successfully deposited on the surface of PAN NFMs, which improved the hydrophobicity by increasing the water contact angle from 46° to 128°, 130°, and 136°, respectively. Besides, the Zn@PAN NFMs sample was showed good antibacterial property against both Gram-negative and Gram-positive bacterial strains. Overall, the NPs@PAN NFMs based spark ablation technology might afford an easy-to-operated design pattern for constructing potential materials for water treatment applications.

Superior long-term anchorage of the bridging stent-grafts from the fenestrated main body endograft could be achieved with the addition of a flared cuff, capable of preventing the previously observed fabric fraying around the fenestration as a result of the balloon angioplasty of the seal zone. This novel stent cuff design will also facilitate more complete biointegration of the devices, eliminate the hemodynamic variation as well as significantly reduce the possibility of a Type III endoleak. The feasibility of this concept is demonstrated by observations made from in-situ tests performed in a Beta endograft design. Flared cuffs made of poly(ε-caprolactone) supported with a weft-knitted polyester structure can be manufactured with various configurations to optimize the transition from the main body of the endograft, thus preventing the currently marketed designs' hemodynamic perturbation while also promoting endograft biointegration. This concept represents an evolution in branch graft design, which may enhance the long-term durability of customized fenestrations and open new applications for in-vivo graft fenestration in the near future. Further ongoing investigation to optimize its structure, X-ray opacity, fixation to the flared stent, and material biocompatibility are still required to build upon this concept's proof.

ABSTRACT The present study aims to evaluate PolyPropylene meltblown nonwoven sorbents as interceptor barrier for oils (motor oil – soybean oil). Experiments carried out in oil-water bath under both static and dynamic conditions. Among tested sorbents, sorbent P3 with porosity 85.93% show high sorption capacity. In which it achieves the highest absorption values 13.13 and 11.91 g/g for motor oil and soybean oil, respectively. Followed by sorbent P2 with porosity 88.30% and sorbent P1 with porosity 91.46%. Besides, results show that sorbent P1 registered the highest oil retention rate followed by sorbent P2 and sorbent P3, respectively. The SEM observation indicates that pore size and porosity play a significant role in deciding oil sorption and retention. At static condition, oil interception performance was evaluated. oil begins to break through the interceptor barrier in sorbent P3 at 29 min for motor oil with intercepting efficiency 98.00% and at 22 min for soybean oil with intercepting efficiency 96.57%. As the thickness of the interceptor barrier increases the time for initial leakage prolonged. After oil leakage, steady oil spillage took place. The typical oil leaking rate was divided into three phases in which oils leaks sharply increased rate, decrease rate and finally gently. Under dynamic conditions, quickly oil leakage happens compared to a static condition. With water flow rate 166 ml/s, the initial oil leakage for sorbent P3 shortens at 16 min for motor oil and 7 min for soybean oil, with Interception efficiencies at 93.42% and 90.00%, respectively. GRAPHICAL ABSTRACT

The preparation of portable colorimetric biosensor strips is described by combining aptamer-immobilized electrospun nanofiber membranes (A-NFMs) with signal probes (DNA-conjugated gold nanoparticles (AuNPs)) for determination of kanamycin (KMC) as a model analyte. The A-NFMs were decorated with complementary single-stranded DNA (cDNA) of KMC aptamer-conjugated AuNPs (cDNA@Au) to get the colorimetric biosensor strips. The constructed biosensor strips showed a significant absorbance decreasing band at 510 nm which induce a visual color change from pink to white when exposed to KMC, with a low detection limit of 2.5 nM (at S/N = 3). The effect is due to disassembling of cDNA@Au from NFMs in the presence of KMC because the aptamer has a higher affinity to KMC than its complementary DNA, which resulted in replacing cDNA@Au with KMC. Satisfactory performance was observed in real sample (drinking water and milk) analysis with a recovery of 98.9–102.2%. The constructed colorimetric biosensor test strips hold great application promise for food safety control.

Sustainability and environmental consciousness directed attention toward research and innovation in the field of natural fiber composites. Baobab (Adansonia digitata L.) is tropical tree of the silk-cotton family that is native to Africa. The aim of this study is to pore over the use of baobab bast fibers as potential reinforcement in polymer composites. The baobab bast fibers were extracted from the bark of baobab tree in Sudan. Fibers were investigated by chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and single fiber tensile test. Further, the density and relative humidity of fibers were determined.The cellulose, hemicellulose, lignin, ash, and moisture contents present in the fiber are 60.70%, 21.98%, 5.91%, 5.32%, 13%, respectively. The fiber has a density of 1.1041 g/cm3. FTIR spectra for cellulose and nanocellulose confirms absorption bands characteristic of pure celluloses at 3330, 2919, 1640, 1028. Scanning electron micrographs showed roughening of the fiber surface and crack-like lines indicate fiber clusters being held together. The baobab fiber possessed a crystallinity index of 48.01% with thermal stability up to 250°C. The results revealed that baobab fiber can be utilized as reinforcement in polymer composites.

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.

For the purpose of improving sensor detection performance, nanofibers have been introduced into the configuration of sensing response materials. Among various nanofiber fabrication techniques, electrospinning is one of the most promising methods. By virtue of electrospun nanofibrous membranes (NMs), the sensor size has been decreased, the surface energy of sensing responding materials has been increased, and the proportion of atoms distributed on the surface has also been increased accordingly. Furthermore, when fiber diameter shrinks from micro- to nanometer, the specific surface area of the NM increases accordingly, which provides a large number of areas and channels that enhance the interaction between determinant and NM, so as to improve the sensitivity. In this chapter, the latest progress in the development of NM-based sensing responding materials and their application and optimization in four predominant sensing schemes (electrochemical, optical, resistive, and mass-change-sensitive sensors) are described.

Materials for the removal and visual monitoring of ultra-trace levels of lead ions (Pb2+) from impaired drinking water are essential and vital to reduce the enormous effect of Pb2+ on human health. However, it remains a significant challenge to achieve both high adsorption capacity and low naked eye detection limit. Here, we present a strategy to create a Pb2+ removal and contamination degree detecting system by combining electrospun nanofibrous membranes (NMs) with a flow-through system. This approach allows amino acids to graft on hydrolyzed-polyacrylonitrile (AA-HPAN) NMs to perform as adsorbents and colorimetric strips with tortuous porous structure and large surface area. The resultant AA-HPAN NMs exhibit the integrated properties of high adsorption capacity and excellent reversibility. Furthermore, the dynamic removal and recognition experiment were performed and a naked-eye detection limit of 0.048 mu M using sodium rhodizonate as the color initiator. Considering the good removal and monitoring performance of the AA-HPAN NMs, this intriguing approach may pave the way for constructing of membranes with the versatility to sever as a preventive strategy to keep the public from Pb2+ exposure.

The colorimetric sensor array has become a good candidate for the detection of antibiotics due to its ease of use, convenience and low cost.

Driven by economic interests, the abuse of antibiotics has become a significant concern for humans worldwide. As one of the most commonly used antibiotics, oxytetracycline (OTC) residue in animal-derived foods occurs occasionally, which has caused danger to humanity. However, there is still no simple and efficient solution to detect OTC residue. Here, an easily-operated colorimetric strategy for OTC detection was developed based on nickel ions (Ni2+) immobilized carboxymethylcellulose/polyacrylonitrile nanofibrous membranes (Ni@CMC/PAN NFMs). Owing to numerous O- and N-containing groups OTC has a strong tendency to complex with Ni2+ on the strips, inducing a color change from light green to yellow visible to the naked eye. The NFMs structural features, CMC functionalization process, and Ni2+ immobilization amount was carefully regulated to assure OTC detection whilst maintaining the inherent characteristics of NFMs. With the benefits of the large specific surface area (SSA) and small pore size of NFMs, the strips not only exhibited a rapid response (2 min), and low detection limit (5 nM) but also performed with good reversibility and selectivity concerning OTC detection over other antibiotics. The successful development of such enchanting nanofibrous materials may provide a new comprehension into the design and improvement of colorimetric strips.

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.

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 m2 g−1). The color of the resultant NFMs, measured at a wavelength of 420 nm, is red-shifted when exposed to copper ions (Cu2+) 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 Cu2+ upon which soluble thiosulfate complexes of Ag+, Au3+ and Cu2+ 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 Cu2+ in drinking water sample.

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 tissue-engineered 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(e-caprolactone) (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 present study was designed to improve the mechanical performance of a small-diameter vascular prosthesis made from a flexible membrane of poly(ε-caprolactone) (PCL). PCL reinforcement was achieved by embedding a tubular fabric knitted from polyethylene terephthalate (PET) yarns within the freeze-dried composite structure. The knitting density of PET fabric influenced the mechanical properties of the new vascular graft. Results showed that the composite prototype has good mechanical properties, water permeability, elastic recovery, and suture retention strength. Increases in loop density increased compressive strength and suture retention strength and decreased elastic recovery. The new composite prototype vascular graft has promising potential applications in clinics because of its excellent mechanical properties.

Biodegradable polymers have been used in biomedical applications generally, and in tissue engineering especially, due to good physical and biological properties. Poly-epsilon- caprolactone (PCL) is a one of biodegradable polymers, which has a long time of degradation. But the mechanical properties, biodegradability and biocompatibility of the pure PCL cannot meet up with the requirement for some of the biomedical applications such as bone tissue engineering, for that many researches have established to focus on the modification of the PCL. In this review, different results on the fabrication of PCL for specific field of tissue engineering, tissue engineering incorporated in different PCL, surface modifications, blending with other polymers and their micro-porous structure are represented in brief outcomes. In addition dissolution of PCL in different organic solvents and the effect on their properties was attainable. Moreover, the physical and biological properties of PCL for different type of tissue engineering applications (hard and soft tissue) are obtainable.

A new scaffold has been developed,which made from poly(e-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.

The purpose of the vascular grafts or implantation is not only to keep a patient alive, but for the patient to continue with their normal lives. Polyethylene terephthalate (PET) has been successfully used in large diameter grafts; unfortunately, small diameter grafts were failures. Due to surface forces, blood plasma proteins are adsorbed by the graft, resulting vessel reclosure. Poly (e-caprolactone) (PCL) is a promising biodegradable polymer with a longer degradation time. The mechanical properties of the pure PCL membrane cannot meet the requirement. The aim of this study is to develop new vascular graft from PCL reinforced with PET monofilament weft-knitted tube fabric. The PET fabrics were knitted using small single jersey knitting machine. Then PCL solution was coated outside and inside of the weft-knitted fabric with a PTFE rod, and the pure PCL tube was taken as a control. The samples were dried by freeze drying method. The results have shown that the new vascular grafts have good porosity. In addition the tensile properties, elastic recovery and the suture retention strength of the new prototype vascular grafts were improved compared with pure PCL vascular graft, which could be used in clinical application.