Prospects of Nanotechnology in Clinical Immunodiagnostics

Nanostructured materials are promising compounds that offer new opportunities as sensing platforms for the detection of biomolecules. Having micrometer-scale length and nanometer-scale diameters, nanomaterials can be manipulated with current nanofabrication methods, as well as self-assembly techniques, to fabricate nanoscale bio-sensing devices. Nanostructured materials possess extraordinary physical, mechanical, electrical, thermal and multifunctional properties. Such unique properties advocate their use as biomimetic membranes to immobilize and modify biomolecules on the surface of nanoparticles. Alignment, uniform dispersion, selective growth and diameter control are general parameters which play critical roles in the successful integration of nanostructures for the fabrication of bioelectronic sensing devices. In this review, we focus on different types and aspects of nanomaterials, including their synthesis, properties, conjugation with biomolecules and their application in the construction of immunosensing devices. Some key results from each cited article are summarized by relating the concept and mechanism behind each sensor, experimental conditions and the behavior of the sensor under different conditions, etc. The variety of nanomaterial-based bioelectronic devices exhibiting novel functions proves the unique properties of nanomaterials in such sensing devices, which will surely continue to expand in the future. Such nanomaterial based devices are expected to have a major impact in clinical immunodiagnostics, environmental monitoring, security surveillance and for ensuring food safety

Recent Advancements in Polyphenylsulfone Membrane Modification Methods for Separation Applications

Polyphenylsulfone (PPSU) membranes are of fundamental importance for many applications such as water treatment, gas separation, energy, electronics, and biomedicine, due to their low cost, controlled crystallinity, chemical, thermal, and mechanical stability. Numerous research studies have shown that modifying surface properties of PPSU membranes influences their stability and functionality. Therefore, the modification of the PPSU membrane surface is a pressing issue for both research and industrial communities. In this review, various surface modification methods and processes along with their mechanisms and performance are considered starting from 2002. There are three main approaches to the modification of PPSU membranes. The first one is bulk modifications, and it includes functional groups inclusion via sulfonation, amination, and chloromethylation. The second is blending with polymer (for instance, blending nanomaterials and biopolymers). Finally, the third one deals with physical and chemical surface modifications. Obviously, each method has its own limitations and advantages that are outlined below. Generally speaking, modified PPSU membranes demonstrate improved physical and chemical properties and enhanced performance. The advancements in PPSU modification have opened the door for the advance of membrane technology and multiple prospective applications

Growth of 1-D TiO 2

The growth of titania nanowires by a simple metal oxidation process was investigated for both commercially pure α-Ti and Ti alloys including Ti64 and β-Ti under a limited supply of oxygen. The effects of processing variables including heat treatment temperature, gas flow rate, and process duration on the growth of nanowires were explored. Similarities and differences in the growth of nanowires on pure Ti versus Ti alloys were observed. While the growth window in terms of temperature and flow rate is narrow in pure Ti, the window is much wider in the alloys. However, the trend towards high temperature is similar in all the samples promoting faceted oxide crystal growth rather than nanowires

Scale Design of Dual-Layer Polyphenylsulfone/Sulfonated Polyphenylsulfone Hollow Fiber Membranes for Nanofiltration

This study focuses on the synthesis and characterization of dual-layer sulfonated polyphenylenesulfone (SPPSu) nanocomposite hollow fiber nanofiltration membranes incorporating titanium dioxide (TiO2) nanoparticles through the phase inversion technique. Advanced tools and methods were employed to systematically evaluate the properties and performance of the newly developed membranes. The investigation primarily centered on the impact of TiO2 addition in the SPPSu inner layer on pure water permeability and salt rejection. The nanocomposite membranes exhibited a remarkable three-fold increase in pure water permeability, achieving a flux of 5.4 L/m2h.bar compared to pristine membranes. The addition of TiO2 also enhanced the mechanical properties, with an expected tensile strength increase from 2.4 to 3.9 MPa. An evaluation of salt rejection performance using a laboratory-scale filtration setup revealed a maximal rejection of 95% for Mg2SO4, indicating the effective separation capabilities of the modified dual-layer hollow fiber nanocomposite membranes for divalent ions. The successful synthesis and characterization of these membranes highlight their potential for nanofiltration processes, specifically in selectively separating divalent ions from aqueous solutions, owing to their improved pure water flux, mechanical strength, and salt rejection performance

Dye Separation and Antibacterial Activities of Polyaniline Thin Film-Coated Poly(phenyl sulfone) Membranes

We fabricated a nanofiltration membrane consisting of a polyaniline (PANI) film on a polyphenylsulfone (PPSU) substrate membrane. The PANI film acted as a potent separation enhancer and antimicrobial coating. The membrane was analyzed via scanning electron microscopy and atomic force microscopy to examine its morphology, topography, contact angle, and zeta potential. We aimed to investigate the impact of the PANI film on the surface properties of the membrane. Membrane performance was then evaluated in terms of water permeation and rejection of methylene blue (MB), an organic dye. Coating the PPSU membrane with a PANI film imparted significant advantages, including finely tuned nanometer-scale membrane pores and tailored surface properties, including increased hydrophilicity and zeta potential. The PANI film also significantly enhanced separation of the MB dye. The PANI-coated membrane rejected over 90% of MB with little compromise in membrane permeability. The PANI film also enhanced the antimicrobial activity of the membrane. The bacteriostasis (BR) values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Escherichia coli were 63.5% and 95.2%, respectively. The BR values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Staphylococcus aureus were 70.6% and 88.0%, respectively

Polyphenylsulfone membrane blended with polyaniline for nanofiltration promising for removing heavy metals (Cd2+/Pb2+) from wastewater

This study reported polyaniline (PANi), an emerging multifunctional nanomaterial, for fabricating the polyphenylsulfone (PPSF)–PANi nanocomposite membrane for nanofiltration (NF) to remove heavy metals (Cd2+/Pb2+) from wastewater. PANi was synthesized via oxidative polymerization of an aniline monomer at a low concentration (≤0.1 M). Furthermore, the nanostructure of PANi was determined using transmission electron microscopy. The membrane structure and characteristic properties were studied in terms of surface and cross-section morphologies, topography, hydrophilicity, and surface charge using scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) measurement, and zeta potential measurement, respectively. Thermal and mechanical properties and casting solution viscosity were also studied. The SEM results demonstrated that PANi inclusion helped to construct a typical asymmetric membrane with a pore size of ∼1 nm. Additionally, it enhanced the surface properties, which was indicated by a more considerable hydrophilicity (CA ≤ 52) and a shift in the zeta potential from −40 to −10 mV. Increasing the PANi concentration from 0.25 to 0.50 wt% aided the heavy metal rejection by the nanocomposite membrane, affording an increase of the Cd2+/Pb2+ rejection. However, the Cd2+/Pb2+ rejection decreased when the PANi concentration was 1.0 wt%. The optimized PPSF–PANi nanocomposite membrane at 0.50-wt% PANi exhibited a water permeability of 1.8 LMH/bar and high rejections of 99% and 95% toward Pb2+ and Cd2+, respectively. Tensile strength and TGA tests also revealed the role of PANi as a positive reinforcement on the mechanical and thermal properties of the membrane

Preparation and Characterization of Polyanhydride Terminated with Oleic Acid Extracted from Olive Mills Waste

Valorizing the fatty content of agricultural waste in material synthesis is an interesting topic. This work focused on utilizing oleic acid from the solid waste of olive mills in Saudi Arabia to synthesize biodegradable polyanhydrides based on sebacic acid which terminated with different concentrations of fatty acid (10, 30, 50, and 70 wt%), then characterize the final polymer samples and study the effects of termination on polyanhydrides properties, such as molecular weight and degradation profile. The fatty content of the solid waste was extracted, purified, and analyzed prior to and after separating the saturated and unsaturated fractions by urea crystallization, then the microwave-assisted melt polycondensation technique was used in the synthesis of the final polymers. Molecular weights were determined by gel permeation chromatography (GPC), and the degradation profile of the prepared samples was examined by determining the weight loss percentage of the polymer mass and FT-IR scanning for the anhydride bond before and after sample degradation. Results showed a linear degradation profile for most samples with no significant change in the molecular weights due to termination

Optimization of Synthesis Parameters for Mesoporous Shell Formation on Magnetic Nanocores and Their Application as Nanocarriers for Docetaxel Cancer Drug

In this work, Fe3O4@SiO2 nanoparticles were coated with mesoporous silica shell by S−N+I− pathway by using anionic surfactant (S−) and co-structure directing agent (N+). The role of co-structure directing agent (CSDA) is to assist the electrostatic interaction between negatively charged silica layers and the negatively charged surfactant molecules. Prior to the mesoporous shell formation step, magnetic cores were coated with a dense silica layer to prevent iron oxide cores from leaching into the mother system under any acidic circumstances. However, it was found that both dense and mesoporous coating parameters affect the textural properties of the produced mesoporous silica shell (i.e., surface area, pore volume and shell thickness). The synthesized Fe3O4@SiO2@m-SiO2 (MCMSS) nanoparticles have been characterized by low-angle X-ray diffraction, transmission electron microscopy (TEM), and N2 adsorption-desorption analysis, and magnetic properties. The synthesized particles had dense and mesoporous silica shells of 8–37 nm and 26–50 nm, respectively. Furthermore, MCMSS possessed surface area of ca. 259–621 m2·g−1, and pore volume of ca. 0.216–0.443 cc·g−1. MCMSS showed docetaxcel cancer drug storage capacity of 25–33 w/w% and possessed control release from their mesochannels which suggest them as proper nanocarriers for docetaxcel molecules

Influence of indenter shape on DLC film failure during multiple load cycle nanoindentation

The aim of the present investigation is to understand the localised failure mechanism of diamond-like carbon (DLC) film during multiple load cycle nanoindentation. The DLC film investigated was 500 nm thick sputter coated on Si (100) wafer of 500 μm thickness. Multiple load cycle nanoindentation tests under diamond Berkovich and conical indenters were performed using a calibrated NanoTest at five different load ranges between 0·1 and 500 mN. Test results indicated forward deviation, no deviation and backward deviation of the force–displacement profile, which provided some insights to the mechanisms of localised film failure. During backward deviation, film failure starts from interfacial delamination. This was observed for a conical indenter in a particular load range (1–10 mN). An elastic finite element model during nanoindentation loading indicated that this was caused by the location of maximum stress near the interface. Forward depth deviation was observed for conical and Berkovich indenter at all the other load ranges