Development of a simple polymer-based sensor for detection of the Pirimicarb pesticide

In this study, a sensitive and selective fluorescent chemosensor was developed for the determination of pirimicarb pesticide by adopting the surface molecular imprinting approach. The magnetic molecularly imprinted polymer (MIP) nanocomposite was prepared using pirimicarb as the template molecule, CuFe2O4 nanoparticles, and graphene quantum dots as a fluorophore (MIP-CuFe2O4/GQDs). It was then characterized using X-ray diffraction (XRD) technique, Fourier transforms infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The response surface methodology (RSM) was also employed to optimize and estimate the effective parameters of pirimicarb adsorption by this polymer. According to the experimental results, the average particle size and imprinting factor (IF) of this polymer are 53.61 nm and 2.48, respectively. Moreover, this polymer has an excellent ability to adsorb pirimicarb with a removal percentage of 99.92 at pH = 7.54, initial pirimicarb concentration = 10.17 mg/L, polymer dosage = 840 mg/L, and contact time = 6.15 min. The detection of pirimicarb was performed by fluorescence spectroscopy at a concentration range of 0-50 mg/L, and a sensitivity of 15.808 a.u/mg and a limit of detection of 1.79 mg/L were obtained. Real samples with RSD less than 2 were measured using this chemosensor. Besides, the proposed chemosensor demonstrated remarkable selectivity by checking some other insecticides with similar and different molecular structures to pirimicarb, such as diazinon, deltamethrin, and chlorpyrifos.

Recent advances in gold nanoparticles-based biosensors for tuberculosis determination

Tuberculosis (TB) is one of the major killer diseases affecting lung parenchymal tissues. Mycobacterium tuberculosis (Mtb) is the bacterium that causes it. It most commonly affects the lungs, although it can affect any part of the body, including the stomach, glands, bones, and nervous system. Although anti-mycobacterial drugs are available, it remains a major threat to public health due to the rise of drug-resistant strains, and early and accurate diagnosis is very important. Currently, research science and medical communities are focusing on the use of cost-effective biosensors to manage human biological processes and assess accurate health diagnostics. Due to their high sensitivity in chemical and biological assays, nanomaterials have been considered in the field of biosensors for better diagnosis, and among them, gold nanoparticles (AuNPs) can play an important role in accelerating the diagnosis of TB. Superior biocompatibility, conductivity, catalytic properties, high surface-to-volume ratio, and high density enable their widespread use in the fabrication of biosensors. This review evaluates the diagnostic accuracy of AuNP-based biosensors for the detection of Mtb. According to different transducers of biosensors, their structure, performance, advantages and limitations are summarized and compared. Moreover, the upcoming challenges in their analytical performance have been highlighted and the strategies to overcome those challenges have been briefly discussed.

Tetracycline hydrochloride loaded-alginate based nanoparticle-hydrogel beads for potential wound healing applications: In vitro drug delivery, release kinetics, and antibacterial activity

Novel hydrogel beads based on nanocomposite with outstanding antibacterial and swelling capabilities have been successfully produced as an efficient drug carrier for potential drug delivery systems in wound healing applications. The beads were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and EDX-Mapping analysis. Then, using tetracycline hydrochloride (TCH) as a model drug system, they were studied in vitro for their potential efficiency as pH and temperature dependent sustained drug delivery carriers. Moreover, they were assessed in terms of porosity, swelling degree, encapsulation efficiency, and in vitro release kinetics. Beads released drugs at their highest levels under alkaline circumstances (pH = 8) and at a temperature of 39 °C, with a cumulative TCH release of 96.2 % at 36 h and in accordance with the Weibull kinetics model (R2 = 0.98). Additionally, the disc diffusion experiment demonstrated the strong antibacterial activity of the synthesized beads and offered a feasible and cost-effective wound dressing material for treating infected wounds.

Effects of mechanical properties of carbon-based nanocomposites on scaffolds for tissue engineering applications: a comprehensive review

Mechanical properties, such as elasticity modulus, tensile strength, elongation, hardness, density, creep, toughness, brittleness, durability, stiffness, creep rupture, corrosion and wear, a low coefficient of thermal expansion, and fatigue limit, are some of the most important features of a biomaterial in tissue engineering applications. Furthermore, the scaffolds used in tissue engineering must exhibit mechanical and biological behaviour close to the target tissue. Thus, a variety of materials has been studied for enhancing the mechanical performance of composites. Carbon-based nanostructures, such as graphene oxide (GO), reduced graphene oxide (rGO), carbon nanotubes (CNTs), fibrous carbon nanostructures, and nanodiamonds (NDs), have shown great potential for this purpose. This is owing to their biocompatibility, high chemical and physical stability, ease of functionalization, and numerous surface functional groups with the capability to form covalent bonds and electrostatic interactions with other components in the composite, thus significantly enhancing their mechanical properties. Considering the outstanding capabilities of carbon nanostructures in enhancing the mechanical properties of biocomposites and increasing their applicability in tissue engineering and the lack of comprehensive studies on their biosafety and role in increasing the mechanical behaviour of scaffolds, a comprehensive review on carbon nanostructures is provided in this study.