Silica NPs in PLA-Based Electrospun Nanofibrous Non-Woven Protective Fabrics with Dual Hydrophilicity/Hydrophobicity, Breathability, and Thermal Insulation Characteristics for Individuals with Disabilities.

A perfect protective fabric for handicapped individuals must be lightweight, waterproof, breathable, and able to absorb water. We present a multifunctional protective fabric in which one side is hydrophobic based on the intrinsic hydrophobic biopolymer polylactic acid (PLA) to keep the disabled person from getting wet, while the other side is super-hydrophilic due to embedded silica nanoparticles (NPs) to keep the disabled person safe from a sudden spill of water or other beverage on their skin or clothes. The porosity of the electrospun nanofibrous structure allows the fabric to be breathable, and the silica NPs play an important role as a perfect infrared reflector to keep the person's clothing cool on warm days. Adding white NPs, such as silicon dioxide, onto or into the textile fibers is an effective method for producing thermally insulated materials. Due to their ability to efficiently block UV light, NPs in a network keep the body cool. Such a multifunctional fabric might be ideal for adult bibs and aprons, outdoor clothing, and other amenities for individuals with disabilities.

Toward the Real-Time and Rapid Quantification of Bacterial Cells Utilizing a Quartz Tuning Fork Sensor.

The quantitative evaluation of bacterial populations is required in many studies, particularly in the field of microbiology. The current techniques can be time-consuming and require a large volume of samples and trained laboratory personnel. In this regard, on-site, easy-to-use, and direct detection techniques are desirable. In this study, a quartz tuning fork (QTF) was investigated for the real-time detection of E. coli in different media, as well as the ability to determine the bacterial state and correlate the QTF parameters to the bacterial concentration. QTFs that are commercially available can also be used as sensitive sensors of viscosity and density by determining the QTFs' damping and resonance frequency. As a result, the influence of viscous biofilm adhered to its surface should be detectable. First, the response of a QTF to different media without E. coli was investigated, and Luria-Bertani broth (LB) growth medium caused the largest change in frequency. Then, the QTF was tested against different concentrations of E. coli (i.e., 102-105 colony-forming units per milliliter (CFU/mL)). As the E. coli concentration increased, the frequency decreased from 32.836 to 32.242 kHz. Similarly, the quality factor decreased with the increasing E. coli concentration. With a coefficient (R) of 0.955, a linear correlation between the QTF parameters and bacterial concentration was established with a 26 CFU/mL detection limit. Furthermore, a considerable change in frequency was observed against live and dead cells in different media. These observations demonstrate the ability of QTFs to distinguish between different bacterial states. QTFs allow real-time, rapid, low-cost, and non-destructive microbial enumeration testing that requires only a small volume of liquid sample.

Developing PMMA/Coffee Husk Green Composites to Meet the Individual Requirements of People with Disabilities: Hip Spacer Case Study.

When replacing a damaged artificial hip joint, treatment involves using antibiotic-laced bone cement as a spacer. One of the most popular materials used for spacers is PMMA; however, it has limitations in terms of mechanical and tribological properties. To overcome such limitations, the current paper proposes utilizing a natural filler, coffee husk, as a reinforcement for PMMA. The coffee husk filler was first prepared using the ball-milling technique. PMMA composites with varying weight fractions of coffee husk (0, 2, 4, 6, and 8 wt.%) were prepared. The hardness was measured to estimate the mechanical properties of the produced composites, and the compression test was utilized to estimate the Young modulus and compressive yield strength. Furthermore, the tribological properties of the composites were evaluated by measuring the friction coefficient and wear by rubbing the composite samples against stainless steel and cow bone counterparts under different normal loads. The wear mechanisms were identified via scanning electron microscopy. Finally, a finite element model for the hip joint was built to investigate the load-carrying capacity of the composites under human loading conditions. The results show that incorporating coffee husk particles can enhance both the mechanical and tribological properties of the PMMA composites. The finite element results are consistent with the experimental findings, indicating the potential of the coffee husk as a promising filler material for enhancing the performance of PMMA-based biomaterials.

Preparation and Characterization of Electrospun Poly(lactic acid)/Poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol)/Silicon Dioxide Nanofibrous Adsorbents for Selective Copper (II) Ions Removal from Wastewater.

The problem of industrial wastewater containing heavy metals is always a big concern, especially Cu2+, which interprets the soil activity in farmland and leaves a negative impact on the environment by damaging the health of animals. Various methods have been proposed as countermeasures against heavy-metal contaminations, and, as a part of this, an electrospun nanofibrous adsorption method for wastewater treatment is presented as an alternative. Poly(lactic acid) (PLA) is a biopolymer with an intrinsic hydrophobic property that has been considered one of the sustainable nanofibrous adsorbents for carrying adsorbate. Due to the hydrophobic nature of PLA, it is difficult to adsorb Cu2+ contained in wastewater. In this study, the hydrophilic PLA/poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEG-PPG-PEG) nanofibrous adsorbents with different silicon dioxide (SiO2) concentrations were successfully prepared by electrospinning. A hydrophilic group of PEG-PPG-PEG was imparted in PLA by the blending method. The prepared PLA/PEG-PPG-PEG/SiO2 nanofibrous adsorbents were analyzed with their morphological, contact angle analysis, and chemical structure. The Cu2+ adsorption capacities of the different PLA/PEG-PPG-PEG/SiO2 nanofibrous adsorbents were also investigated. The adsorption results indicated that the Cu2+ removal capacity of PLA/PEG-PPG-PEG/SiO2 nanofibrous adsorbents was higher than that of pure ones. Additionally, as an affinity nanofibrous adsorbent, its adsorption capacity was maintained after multiple recycling processes (desorption and re-adsorption). It is expected to be a promising nanofibrous adsorbents that will adsorb Cu2+ for wastewater treatment.

Microelectromechanical system-based biosensor for label-free detection of human cytomegalovirus.

The human cytomegalovirus (HCMV) is an asymptomatic common virus that is typically harmless, but in some cases, it can be life threatening. Thus, there is an urgent need to develop novel diagnostic methods and strengthen the efforts to combat this virus. A microcantilever-based biosensor functionalised with the UL83-antibody of HCMV (UL83-HCMV antibody) has been developed to detect the UL83-antigen of HCMV (UL83-HCMV antigen) at different concentrations ranging from 0.3 to 300 ng/ml. The response of the biosensor to the presence of UL83-HCMV antigen was measured through the shift in resonance frequency before and after antigen-antibody binding. The system shows a low detection limit of 84 pg/ml, which is comparable to traditional sensors, and a detection time of less than 15 min was achieved. The selectivity of the sensor was demonstrated using three different proteins with and without the UL83-HCMV antigen. The biosensor shows high selectivity for the UL83-HCMV antigen. Mass loading by the UL83-HCMV antigen was roughly estimated with a sensitivity of ∼30 fg/Hz. This technique is crucial for the fabrication of portable and low-cost biosensors that can be used in real-time monitoring and enables early medical diagnosis.

Evaluating the Mechanical and Tribological Properties of 3D Printed Polylactic-Acid (PLA) Green-Composite for Artificial Implant: Hip Joint Case Study.

Artificial implants are very essential for the disabled as they are utilized for bone and joint function in orthopedics. However, materials used in such implants suffer from restricted mechanical and tribological properties besides the difficulty of using such materials with complex structures. The current study works on developing a new polymer green composite that can be used for artificial implants and allow design flexibility through its usage with 3D printing technology. Therefore, a natural filler extracted from corn cob (CC) was prepared, mixed homogeneously with the Polylactic-acid (PLA), and passed through a complete process to produce a green composite filament suit 3D printer. The corn cob particles were incorporated with PLA with different weight fractions zero, 5%, 10%, 15%, and 20%. The physical, mechanical, and tribological properties of the PLA-CC composites were evaluated. 3D finite element models were constructed to evaluate the PLA-CC composites performance on a real condition implant, hip joints, and through the frictional process. Incorporating corn cob inside PLA revealed an enhancement in the hardness (10%), stiffness (6%), compression ultimate strength (12%), and wear resistance (150%) of the proposed PLA-CC composite. The finite element results of both models proved an enhancement in the load-carrying capacity of the composite. The finite element results came in line with the experimental results.

Reduced graphene oxide supported MXene based metal oxide ternary composite electrodes for non-enzymatic glucose sensor applications.

Diagnosis and monitoring of glucose level in human blood has become a prime necessity to avoid health risk and to cater this, a sensor's performance with wide linearity range and high sensitivity is required. This work reports the use of ternary composite viz. MG-Cu2O (rGO supported MXene sheet with Cu2O) for non-enzymatic sensing of glucose. It has been prepared by co-precipitation method and characterized with X-ray powder diffraction, Ultraviolet-visible absorption spectroscopy (UV-Vis), Raman spectroscopy, Field emission scanning electron microscopy, High resolution transmission electron microscopy and Selected area diffraction. These analyses show a cubic structure with spherical shaped Cu2O grown on the MG sheet. Further, the electrocatalytic activity was carried out with MG-Cu2O sensing element by cyclic voltammetry and chronoamperometry technique and compared with M-Cu2O (MXene with Cu2O) composite without graphene oxide. Of these, MG-Cu2O composite was having the high defect density with lower crystalline size of Cu2O, which might enhance the conductivity thereby increasing the electrocatalytic activity towards the oxidation of glucose as compared to M-Cu2O. The prepared MG-Cu2O composite shows a sensitivity of 126.6 µAmM-1 cm-2 with a wide linear range of 0.01to 30 mM, good selectivity, good stability over 30 days and shows a low Relative Standard Deviation (RSD) of 1.7% value towards the sensing of glucose level in human serum. Thus, the aforementioned finding indicates that the prepared sensing electrode is a well suitable candidate for the sensing of glucose level for real time applications.

Evaluating the Performance of 3D-Printed PLA Reinforced with Date Pit Particles for Its Suitability as an Acetabular Liner in Artificial Hip Joints.

Off-the-shelf hip joints are considered essential parts in rehabilitation medicine that can help the disabled. However, the failure of the materials used in such joints can cause individual discomfort. In support of the various motor conditions of the influenced individuals, the aim of the current research is to develop a new composite that can be used as an acetabular liner inside the hip joint. Polylactic acid (PLA) can provide the advantage of design flexibility owing to its well-known applicability as a 3D printed material. However, using PLA as an acetabular liner is subject to limitations concerning mechanical properties. We developed a complete production process of a natural filler, i.e., date pits. Then, the PLA and date pit particles were extruded for homogenous mixing, producing a composite filament that can be used in 3D printing. Date pit particles with loading fractions of 0, 2, 4, 6, 8, and 10 wt.% are dispersed in the PLA. The thermal, physical, and mechanical properties of the PLA-date pit composites were estimated experimentally. The incorporation of date pit particles into PLA enhanced the compressive strength and stiffness but resulted in a reduction in the elongation and toughness. A finite element model (FEM) for hip joints was constructed, and the contact stresses on the surface of the acetabular liner were evaluated. The FEM results showed an enhancement in the composite load carrying capacity, in agreement with the experimental results.

Carbon Nanodots-Embedded Pullulan Nanofibers for Sulfathiazole Removal from Wastewater Streams.

Carbon nanodots (CNDs)-embedded pullulan (PUL) nanofibers were developed and successfully applied for sulfathiazole (STZ) removal from wastewater streams for the first time. The CNDs were incorporated into PUL at 0.0%, 1.0%, 2.0%, and 3.0% (w/w) to produce M1, M2, M3, and M4 nanofibers (PUL-NFs), respectively. The produced PUL-NFs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), thermal gravimetric analysis (TGA) and Differential scanning calorimetry (DSC) and applied for STZ removal from aqueous solutions through pH, kinetics, and equilibrium batch sorption trials. A pH range of 4.0-6.0 was observed to be optimal for maximum STZ removal. Pseudo-second order, intraparticle diffusion, and Elovich models were suitably fitted to kinetics adsorption data (R2 = 0.82-0.99), whereas Dubinin-Radushkevich, Freundlich, and Langmuir isotherms were fitted to equilibrium adsorption data (R2= 0.88-0.99). STZ adsorption capacity of PUL-NFs improved as the amount of embedded CNDs increased. Maximum STZ adsorption capacities of the synthesized PUL-NFs were in the order of: M4 > M3 > M2 > M1 (133.68, 124.27, 93.09, and 35.04 mg g-1, respectively). Lewis acid-base reaction and π-π electron donor-acceptor interactions were the key STZ removal mechanisms under an acidic environment, whereas H-bonding and diffusion were key under a basic environment. Therefore, CNDs-embedded PUL-NFs could be employed as an environmentally friendly, efficient, and non-toxic adsorbent to remove STZ from wastewater streams.

Multi-walled carbon nanotube-based nanobiosensor for the detection of cadmium in water.

Industrial and agricultural processes have led to the prevalence of cadmium in the ecosystem. A successive build-up of cadmium in food and drinking water can result in inadvertent consumption of hazardous concentrations. Such environmental contamination of cadmium can pose a substantial threat to human and animal life. In humans, it is known to cause hypertension, cardiovascular diseases, DNA lesions, inhibition of DNA repair protein or disturb the functioning of lung, liver, prostate and kidney. The development of a reliable method for Cd (II) ions detection would reduce the exposure and complement existing conventional methods. In this study, a DNA based electrochemical method is employed for the detection of Cd (II) ions using ethyl green (EG) and multi-walled carbon nanotube (MWCNT). Glassy carbon electrode (GCE)/MWCNT forms the working electrode for differential pulse voltammetry (DPV) analysis for the detection of Cd (II) ions. The dsDNA is immobilized onto the working electrode. The indicator dye EG, preferably binds to ssDNA and its reduction peak current is noticeably less in the presence of dsDNA. The Cd (II) ions after interacting with dsDNA, unwinds the dsDNA to ssDNA, upon which the EG molecules bind to ssDNAs, giving a higher reduction peak current. The difference in the reduction peak currents in the presence and absence of Cd (II) ions is proportional to its concentration. The linear detection range achieved in this method is 2 nM-10.0 nM with a sensitivity of around 5 nA nM-1 and the limit of detection is 2 nM, which is less than the permissible limit of WHO for human exposure. This study considerably broadens the possible application of multi-walled carbon nanotube modified electrodes as biosensors and holds prospects for the detection of other heavy metals in environmental samples.

Scaling-up medical technologies using flexographic printing.

Medical technologies, such as point-of-care devices and biological and chemical assays which rely on functional materials deposited on top of substrates, are in great demand due to an increase in the prevalence of diseases worldwide. A significant number of these medical technologies are still in their infancy with respect to commercialization because of the high cost, material and complexity of the conventionally available fabrication techniques. As a result, medical technologies, in broad terms, require low cost and mass production fabrication methods in order to overcome the commercialization challenges. Recently, researchers have explored the flexographic printing technique which is widely employed for food packaging and newspaper production. This technique has proved cost-effective, facile, rapid and industrially compatible fabrication technique of functional materials for various applications. In this review, we provide an account of the attempts of flexographic printing made to scale up functional materials on surfaces for biomedical applications. Firstly, we offer justification for demanding high-throughput fabrication techniques. We then present the facile working principle of the flexographic printing and its use in different medical applications, for example chronic disease monitoring devices, colorimetric sensors, electrochemical sensors, assays and drugs. Finally, we discuss challenges of the fabrication technique. The main purpose of this review is to give insights into the usefulness of flexographic printing to the health care industry.

Nanotextured Surface on Flexographic Printed ZnO Thin Films for Low-Cost Non-Faradaic Biosensors.

In this work, the formation of a nanotextured surface is reported on flexographic printed zinc oxide thin films which provide an excellent platform for low-cost, highly sensitive biosensing applications. The ability to produce nanotextured surfaces using a high-throughput, roll-to-roll production method directly from precursor ink without any complicated processes is commercially attractive for biosensors that are suitable for large-scale screening of diseases at low cost. The zinc oxide thin film was formed by printing a zinc acetate precursor ink solution and annealing at 300 °C. An intricate nanotexturing of the film surface was achieved through 150 °C drying process between multiple prints. These surface nanostructures were found to be in the range of 100 to 700 nm in length with a width of 58 ± 18 nm and a height of between 20 and 60 nm. Such structures significantly increase the surface area to volume ratio of the biosensing material, which is essential to high sensitivity detection of diseases. Nonfaradaic electrochemical impedance spectroscopy measurements were carried out to detect the pp65-antigen of the human cytomegalovirus using the printed device, which has a low limit of detection of 5 pg/mL.