No abstract

A one-step in situ synthesis of nylon 6 nanofi bers fi lled with gold nanoparticles for the colorimetric probe of 1-hydroxypyrene, a biomarker associated with the largest class of cancer-causing chemical compounds polycyclic aromatic hydrocarbons (PAHs) is proposed in this study. The gold nanoparticles (AuNPs) were successfully embedded on the surface of the nylon 6 fi bers where the gold particles were chemisorbed onto the amide groups in the nylon 6 backbones. By electrospinning the nylon 6/gold nanocomposite, the gold nanoparticles were uniformly dispersed on the polymer fi bers to give a photostable reddish white fi ber which turned purple/blue when brought in contact with a standard solution of the biomarker. The TEM revealed the formation of spherical AuNPs with an average diameter of 8 nm well arrayed within the nanofi bers, but no signifi cant change in the morphology of the nanofi bers was observed. The thermal properties of the composite fi bers were greatly improved compared to the electrospun nylon 6 fi ber. The developed method described herein is simple, effective, requires no post-treatments, and is highly sensitive (100 ng/ ml) hence the nanocomposite fi bers can be employed as a test strip for the colorimetric detection of 1-hydroxypyrene in human urine or other diagnostic probe biosensors.Introduction. Metal nanoparticles are of great scientifi c interest as they are effectively a bridge between bulk materials and atomic/molecular structures. Nanoparticles often have unexpected visible properties because they are small enough to confi ne their electrons and produce quantum confi nement effect [1][2][3][4]. Their high surface activity and freely moving electrons can bring about the enhanced Raman scattering effect and agglomeration [1,[5][6][7][8]. The high surface area to volume ratio reduces their incipient melting temperature. They often possess high molar extinction values, which makes them far more sensitive and stable than other conventional colorimetric probes [2]. A prominent spectroscopic feature of the noble metal nanoparticles is surface plasmon resonance (SPR), which arises from the collective resonance oscillations of the free electrons of the conduction band of the metal and often gives rise to a sharp and intense absorption band in the visible range [5,[9][10][11][12]. A combination of these unique properties makes the metal nanoparticles highly promising as the ultimate miniature devices with potential applications in optometrics [1,2,5,13], sensing (biological colorimetric probes) [2, 13-16], catalysis [14,15], labeling, pharmacy (controlled drug release, therapeutic) and modern medicine [2,[14][15][16][17].A gold nanoparticle (AuNP) is one of the few metal nanoparticles that are increasingly drawing huge scientifi c attention as colorimetric probes due to their unique physical and chemical properties. Beside the numerous applications of the AuNPs in catalysis, diagnostics (biomarkers), photo thermal cancer therapy, antibacterials, biology [17][18][19][20], they exhibit an observ...

Background: Synthetic polymers have some qualities that make them good candidates for pre concentration of trace analytes biological fluids because of their great potentials to be functionalized and electrospun into nanofibres.

No abstract

No abstract

Electrospunnanofibers have found myriad of applications from separation science to clinical translation. Electrospunnanofiber scaffolds have the benefits of unique properties such as high surface area to volume ratio, interfibrous pore sizes, strong penetrability, great deal of active sites for adsorption, excellent stability, better targeting, minimum toxicity, high drug-loading capacity, exceptional mechanical properties, flexibility in surface functionality, ease of encapsulation of drugs and bioactive compounds, suitability for thermos-liable drugs, enhanced cellular interactions, and protein absorption to facilitate binding sites for cell receptors. In the field of separation science, electrospunnanofiber scaffolds have extensively served as sorbent material for solid phase extraction techniques mainly due to the need to improve sorptive capacity and analyte selectivity. Given that almost all of the human tissues and organs are deposited in nanofibrous forms or structures, electrospunnanofibers/ nanocomposites are currently being investigated for potential clinical applications. It is noteworthy that the nanofiber fabrication technique and the material integrity are key components to obtaining clinically relevant nanofibers. Owing to the significance of fiber arrangement to nanofiber performance, electrospinning has a leading edge over other nanofiber fabrication techniques due to the ease of controlling fiber orientation, despite the inherent advantages of other conventional nanofiber fabrication techniques. The current review highlights the superb qualities of electrospunnanofibers, their various methods of fabrication, and their various applications especially in separation science and clinically. We further provided an overview of the electrospinning principles, types of electrospinning, parameters that affect the nanofibers fabrication via electrospinning, challenges, and the future directions. The advent of robotics-assisted electrospinning technique offers new opportunities for the traditional biofabrication in higher accuracy and controllability and hence will certainly drive nanotechnology from laboratory/industry toward patient care in the near future.

This paper reviews the most recent findings in the search for small molecule cyclic AMP analogues regarding their potential use in musculoskeletal regenerative engineering.

It is always desirable to achieve maximum sample clean-up, extraction, and pre-concentration with the minimum possible organic solvent. The miniaturization of sample preparation devices was successfully demonstrated by packing 10 mg of 11 electrospun polymer nanofibers into pipette tip micro column and mini disc cartridges for efficient pre-concentration of 1-hydroxypyrene in urine samples. 1-hydroxypyrene is an extensively studied biomarker of the largest class of chemical carcinogens. Excretory 1-hydroxypyrene was monitored with HPLC/fluorescence detector. Important parameters influencing the percentage recovery such as fiber diameter, fiber packing amount, eluent, fiber packing format, eluent volume, surface area, porosity, and breakthrough parameters were thoroughly studied and optimized. Under optimized condition, there was a near perfect linearity of response in the range of 1–1000 μg/L with a coefficient of determination (r2) between 0.9992 and 0.9999 and precision (% RSD) ≤7.64% (n = 6) for all the analysis (10, 25, and 50 μg/L). The Limit of detection (LOD) was between 0.022 and 0.15 μg/L. When compared to the batch studies, both disc packed nanofiber sorbents and pipette tip packed sorbents exhibited evident dominance based on their efficiencies. The experimental results showed comparable absolute recoveries for the mini disc packed fibers (84% for Nylon 6) and micro columns (80% for Nylon 6), although the disc displayed slightly higher recoveries possibly due to the exposure of the analyte to a larger reacting surface. The results also showed highly comparative extraction efficiencies between the nanofibers and conventional C-18 SPE sorbent. Nevertheless, miniaturized SPE devices simplified sample preparation, reducing back pressure, time of the analysis with acceptable reliability, selectivity, detection levels, and environmental friendliness, hence promoting green chemistry.