Nanomaterials for biomedical applications: production, characterisations, recent trends and difficulties

Designing of nanomaterials has now become a top-priority research goal with a view to developing specific applications in the biomedical fields. In fact, the recent trends in the literature show that there is a lack of in-depth reviews that specifically highlight the current knowledge based on the design and production of nanomaterials. Considerations of size, shape, surface charge and microstructures are important factors in this regard as they affect the performance of nanoparticles (NPs). These parameters are also found to be dependent on their synthesis methods. The characterisation techniques that have been used for the investigation of these nanomaterials are relatively different in their concepts, sample preparation methods and obtained results. Consequently, this review article aims to carry out an in-depth discussion on the recent trends on nanomaterials for biomedical engineering, with a particular emphasis on the choices of the nanomaterials, preparation methods/instruments and characterisations techniques used for designing of nanomaterials. Key applications of these nanomaterials, such as tissue regeneration, medication delivery and wound healing, are also discussed briefly. Covering this knowledge gap will result in a better understanding of the role of nanomaterial design and subsequent larger-scale applications in terms of both its potential and difficulties

Barium oxide doped magnesium silicate nanopowders for bone fracture healing: Preparation, characterization, antibacterial and in vivo animal studies

Magnesium silicate (MgS) nanopowders doped with barium oxide (BaO) were prepared by sol-gel technique, which were then implanted into a fracture of a tibia bone in rats for studying enhanced in vivo bone regeneration. The produced nanopowders were characterized using X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscope with energy-dispersive X-ray spectrometry (SEM-EDX) and transmission electron microscope (TEM). Mechanical and bactericidal properties of the nanopowders were also determined. Increased crystallinity particle diameter and surface area were found to decrease after the BaO doping without any no-table alterations on their chemical integrities. Moreover, elevated mechanical and anti-bacterial characteristics were recognized for higher BaO doping concentrations. Our animal studies demonstrated that impressive new bone tissues were formed in the frac-tures whilst the prepared samples degraded, indicating that the osteogenesis and de-gradability of the BaO containing MgS samples were better than the control MgS. The results of the animal study indicated that the simultaneous bone formation on magne-sium biomaterial silicate and barium MgS with completed bone healing after five weeks of implantations. The findings also demonstrated that the prepared samples with good biocompatibility and degradability could enhance vascularization and osteogenesis, and they have therapeutic potential to heal bone fractures.</p

Multifunctional magnetite nanoparticles for drug delivery: preparation, characterisation, antibacterial properties and drug release kinetics

Multifunctional nanoparticles (NPs) with magnetic (M) and antibacterial properties were prepared for drug delivery purposes by a method involving co-precipitation synthesis. Partial and complete substitutions of ferrous ions (Fe2+) by copper ions (Cu2+) were carried out for the preparation of the magnetite NPs, which are designated as Cu0.5M and CuM, respectively, in this work. In addition, chitosan and ciprofloxacin were hybridized with the NPs from the previous step to achieve multifunctional properties. XRD, TEM, SEM/EDAX, VSM and FTIR were subsequently employed to characterize various properties of the prepared NPs, namely, crystallinity, nanostructure (size), particle morphology, elemental mapping, magnetic strength and chemical composition. Antibacterial properties of the NPs were tested against Bacillus cereus (Gram-positive bacteria), Escherichia coli (Gram-negative bacteria) and Candida albicans (yeast). Efficiency of the ciprofloxacin release was also studied for the drug-loaded NPs. It is demonstrated that the obtained NPs possess mixed phases with crystalline structures that are affected by the degree of Cu ion substitution (5-10nm (M), 2.5-3.5nm (Cu0.5M) and 11-16nm (CuM)). Saturation magnetization values of the NPs were recorded as 38.7, 3.5 and 1.3 emu/g, respectively. It was also found that the introduction of Cu ions in the NP samples improved the significance of their antibacterial activity, especially against Escherichia coli. Chitosan and ciprofloxacin were found to have stronger effects against Bacillus cereus and Escherichia coli and lesser effects against Candida albicans. However, the samples containing chitosan, ciprofloxacin and the higher Cu ion concentration exhibited strong influence against Candida albicans. During a study period of 30- days, the amounts of released drug from the tested NPs were 85, 26 and 20% of the originally loaded amount, respectively. Owing to the findings in this paper, the developed NPs are considered to have good potential for drug delivery applications and to study them further such as in pre-clinical studies

Anti-obesity drug delivery systems: recent progress and challenges

Obesity has reached an epidemic proportion in the last thirty years, and it is recognized as a major health issue in modern society now with the possibility of serious social and economic consequences. By the year 2030, nearly 60% of the global population may be obese or overweight, which emphasizes a need for novel obesity treatments. Various traditional approaches, such as pharmacotherapy and bariatric surgery, have been utilized in clinical settings to treat obesity. However, these methods frequently show the possibility of side effects while remaining ineffective. There is, therefore, an urgent need for alternative obesity treatments with improved efficacy and specificity. Polymeric materials and chemical strategies are employed in emerging drug delivery systems (DDSs) to enhance therapy effectiveness and specificity by stabilizing and controlling the release of active molecules such as natural ingredients. Designing DDSs is currently a top priority research objective with an eye towards creating obesity treatment approaches. In reality, the most recent trends in the literature demonstrate that there are not enough in-depth reviews that emphasize the current knowledge based on the creation and design of DDSs for obesity treatment. It is also observed in the existing literature that a complex interplay of different physical and chemical parameters must be considered carefully to determine the effectiveness of the DDSs, including microneedles, for obesity treatment. Additionally, it is observed that these properties depend on how the DDS is synthesized. Although many studies are at the animal-study stage, the use of more advanced DDS techniques would significantly enhance the development of safe and efficient treatment approaches for obese people in the future. Considering these, this review provides an overview of the current anti-obesity treatment approaches as well as the conventional anti-obesity therapeutics. The article aims to conduct an in-depth discussion on the current trends in obesity treatment approaches. Filling in this knowledge gap will lead to a greater understanding of the safest ways to manage obesity.</p

Egyptian corals-based calcium silicate (CaS) nanopowders doped with zinc/copper for improved chemical stability and treatment of calvarial defects

Developing low-cost nano-biomaterials using locally available raw materials is gaining significant prominence recently, e.g., to meet the UN’s sustainable development goals (Goal 3). In this work, amorphous calcium silicate (CaS) nanopowders were prepared from Egyptian corals (CaCO3) as a low-cost bone restoration material due to their excellent bonding abilities with surrounding bone tissues, which in turn accelerated the bone healing process. Some of the developed CaS nanopowders was doped with different concentrations of Cu2+ and Zn2+ at the expense of the inherent Ca2+ in the raw materials. The nanopowders were characterized using X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscope with energy-dispersive X-ray spectrometry (SEM-EDX), transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) surface area measurements. Mechanical and bactericidal properties of the nanopowders were assessed followed by well-defined examinations of their abilities to support cell viability, proliferation and differentiation against osteosarcoma cells (MG63 cell lines). The obtained nanopowders were confirmed to be amorphous in nature with particle diameters mostly in two size ranges, namely, 5–10 nm and 15–92 nm. The nanopowders were found to have a good surface area influenced by the type of dopant materials. Notable enhancement in the mechanical (up to 6.76 MPa compressive strength) and antibacterial behaviors of the CaS nanopowders were observed after Zn2+ doping. The number of the differentiated cells after 72 h of incubation was increased, especially for CaS silicate Zn2+ doped nanopowders. Following these examinations of the nanopowders, their utility for the treatment of calvarial (top part of the skull) defects in a rat model was investigated. The developed Cu2+ or Zn2+ doped nanopowders enhanced the healing rate of calvarial defects and they demonstrated impressive biosafety towards repairing vital organs (brain, liver and kidney).</p

Magnetic nanosystems substituted with zinc for enhanced antibacterial, drug delivery and cell viability behaviours

Nanoparticles (NPs) of magnetite (M) and zinc ferrites (Zn0.5M and ZnM) with different zinc concentrations were synthesized through a co-precipitation method and coated with chitosan containing ciprofloxacin antibiotic to enhance the cells compatibility to these nanosystems. The prepared magnetic nanoparticles (MNPs), chitosan/MNPs and ciprofloxacin/chitosan/MNPs were characterized using X-ray diffraction (XRD), transmittance electron microscopy (TEM), scanning electron microscopy (SEM) accessorized with energy dispersive X-rays (EDAX), vibrating-sample magnetometer (VSM), Fourier transform infrared (FTIR) and BET surface area measurements. Antibacterial properties of the MNPs were examined against Candida albicans (yeast), Bacillus cereus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria).The drug-loaded NPs were also studied for their efficiency of ciprofloxacin release. The average crystallite size of the fabricated NPs was 10.4 nm (Fe3O4) and 14 nm (ZnFe2O4) for samples M and Zn0.5M, respectively. The surface areas of the achieved specimens were recorded to be 145.92±2.32, 102.94±0.39 and 168.71±2.05 m²/g for M, Zn0.5M and ZnM, respectively. The saturation magnetization values were determined to be approximately 38.7, 60.6 and 2 emu/g for M, Zn0.5M and ZnM, respectively. It was revealed that the bactericidal activity towards the tested strains was highly pronounced for the nanosytems containing ciprofloxacin drug alongside with those substituted with zinc. During a period of 30 days, the total dosage of released ciprofloxacin from CipChM, CipChZnM and CipChZn0.5M was 82, 90 and 96%, respectively. Finally, cells viability and proliferation of different cell lines were found to be increased by the developed nanosystems, especially by those containing zinc and chitosan in the presence of extra MNPs. </p