Sustainable Nanomaterials for Biomedical Applications

Alleviation of mycobacterial infection by impairing motility and biofilm formation via natural and synthetic molecules

Mycobacterium species show distinctive characteristics with significant medical implications. Mycobacteria, including Mycobacterium tuberculosis and non-tuberculous mycobacteria, can form biofilms that facilitate their survival in hostile environments and contribute to development of antibiotic resistance and responses by the host immune system. Mycobacterial biofilm development is a complex process involving multiple genetic determinants, notably mmpL genes, which regulate lipid transport and support cell wall integrity, and the groEL gene, which is essential for biofilm maturation. Sliding motility, a passive form of surface movement observed across various mycobacterial species, is closely associated with biofilm formation and colony morphology. The unique sliding motility and biofilm-forming capabilities of Mycobacterium spp. are pivotal for their pathogenicity and persistence in diverse environments. A comprehensive understanding of the regulatory mechanisms governing these processes is crucial for the development of novel therapeutic strategies against mycobacterial infections. This review provides a detailed examination of our current knowledge regarding mycobacterial biofilm formation and motility, with a focus on regulation of these processes, their impact on pathogenicity, and potential avenues for therapeutic intervention. To this end, the potential of natural and synthetic compounds, including nanomaterials, in combating mycobacterial biofilms and inhibiting sliding motility are discussed as well. These compounds offer new avenues for the treatment of drug-resistant mycobacterial infections.

Bacterial nanocelluloses as sustainable biomaterials for advanced wound healing and dressings

Wound healing remains a significant clinical challenge, calling for innovative approaches to expedite the recovery process and improve patient outcomes. Bacterial nanocelluloses (BNCs) have emerged as a promising solution in the field of wound healing and dressings due to their unique properties such as high crystallinity, mechanical strength, high purity, porosity, high water absorption capacity, biodegradability, biocompatibility, sustainability, and flexibility. BNC-based materials can be applied for the treatment of different types of wounds, from second-degree burns to skin tears, biopsy sites, and diabetic and ischemic wounds. BNC-based dressings have exceptional mechanical properties such as flexibility and strength, which ensure proper wound coverage and protection. The renewable nature, eco-friendly production process, longer lifespan, and potential for biodegradability of BNCs make them a more sustainable alternative to conventional wound care materials. This review aims to provide a detailed overview on the application of BNC-based composites for wound healing and dressings via highlighting their ability as a carrier for delivery of different types of antimicrobial compounds as well as their direct effect on the healing process. Besides, it mentions some of the in vivo and clinical studies using BNC-based dressings and describes challenges related to the application of these materials as well as their future directions.

Synthesis and characterization of new electrospun medical scaffold-based modified cellulose nanofiber and bioactive natural propolis for potential wound dressing applications

Recently, the design of polymer nanofibers using the electrospinning process has attracted much interest. Particularly the use of natural polymers has promoted many advantages in their biomedical applications. However, the combination of multiple natural polymers remains a great challenge in terms of electrospun production and applied performance. From this perspective, the current investigation highlights the study of the preparation of electrospun nanomaterial scaffolds based on combined natural polymers for improved wound healing performance. First, we have synthesized a crosslinked polymer by reacting microcrystalline cellulose (MC) and chitosan (CS) biopolymer via the intermediate of citric acid as a crosslinking agent. Then a natural propolis biomolecule was incorporated into the polymer network. Different MC/CS blend ratios of 90/10 and 70/30 were then used and various machine parameters were optimized to obtain nanofiber scaffolds with excellent strength and structures. SEM, IR, physicochemical, mechanical, and morpho-logical characterization were then performed. SEM evaluation revealed homogeneous and bead-free nanofibrous structures, with well-defined morphology and a random deposition that could accurately mimic the extracellular matrix of native skin. The calculated average nanofiber diameters for the MC/CS blend ratios at 90/10 and 70/30 were 431.4 and 441.2 nm, respectively. The results showed that when the chitosan amount increased, larger nanofibers with narrow diameter distribution appeared. The prepared nanomaterials had a significant and close water vapor permeability of about 1735.12 and 1698.52 g per m per day for the two blend ratios of 90/10 and 70/30, respectively. The examination of swelling behavior revealed a noteworthy enhancement in hydrophilicity, a necessary attribute for improved healing efficacy. FT-IR analysis confirmed the success and the stability of the chemical crosslinking reaction between the two biopolymers before nanofiber conception. Excellent mechanical properties were acquired, based on the chitosan content. Both developed nanofiber scaffolds exhibited high tensile strength and Young's modulus values. The incorporation of 30% chitosan versus 10% results in an increase in tensile strength of 11% and 14% in Young's modulus. Therefore, we could adjust the different mechanical properties simply by varying the mixing rate of the electrospun polymers. Using epithelial HepG2 cells, viability and kinetic cell adhesion assays were assessed to obtain biological evaluation. No cytotoxicity was observed and good cytocompatibility was confirmed. Functionalized nanofiber biomaterials with different MC/CS ratios substantiated significant bactericidal effectiveness against Gram-positive and Gram-negative bacterial culture strains. The novel functional electrospun wound dressing scaffold demonstrated effective and promising biomedical performance, healing both acute and chronic wounds.

Nanodrug Delivery Systems for Myasthenia Gravis: Advances and Perspectives

Myasthenia gravis (MG) is a rare chronic autoimmune disease caused by the production of autoantibodies against the postsynaptic membrane receptors present at the neuromuscular junction. This condition is characterized by fatigue and muscle weakness, including diplopia, ptosis, and systemic impairment. Emerging evidence suggests that in addition to immune dysregulation, the pathogenesis of MG may involve mitochondrial damage and ferroptosis. Mitochondria are the primary site of energy production, and the reactive oxygen species (ROS) generated due to mitochondrial dysfunction can induce ferroptosis. Nanomedicines have been extensively employed to treat various disorders due to their modifiability and good biocompatibility, but their application in MG management has been rather limited. Nevertheless, nanodrug delivery systems that carry immunomodulatory agents, anti-oxidants, or ferroptosis inhibitors could be effective for the treatment of MG. Therefore, this review focuses on various nanoplatforms aimed at attenuating immune dysregulation, restoring mitochondrial function, and inhibiting ferroptosis that could potentially serve as promising agents for targeted MG therapy.

Recent Advancements and Unexplored Biomedical Applications of Green Synthesized Ag and Au Nanoparticles: A Review

Green synthesis of silver (Ag) and gold (Au) nanoparticles (NPs) has acquired huge popularity owing to their potential applications in various fields. A large number of research articles exist in the literature describing the green synthesis of Ag and Au NPs for biomedical applications. However, these findings are scattered, making it time-consuming for researchers to locate promising advancements in Ag and Au NPs synthesis and their unexplored biomedical applications. Unlike other review articles, this systematic study not only highlights recent advancements in the green synthesis of Ag and Au NPs but also explores their potential unexplored biomedical applications. The article discusses the various synthesis approaches for the green synthesis of Ag and Au NPs highlighting the emerging developments and novel strategies. Then, the article reviews the important biomedical applications of green synthesized Ag and Au NPs by critically evaluating the expected advantages. To expose future research direction in the field, the article describes the unexplored biomedical applications of the NPs. Finally, the articles discuss the challenges and limitations in the green synthesis of Ag and Au NPs and their biomedical applications. This article will serve as a valuable reference for researchers, working on green synthesis of Ag and Au NPs for biomedical applications.

Characterization of Pure and Doped ZnO Nanostructured Powders elaborated in Solar Reactor

The synthesis of nano-oxides is an important field of nanotechnology, as these materials possess unique properties and applications. Several methods have been developed for synthesizing nano-oxides, each offering advantages and disadvantages depending on the desired material characteristics. Solar energy focused on solar reactors can be utilized for nano-oxide elaboration, offering a sustainable and environmentally friendly approach. The current article presents the research carried out for the elaboration of pure and doped nanostructured zinc oxides using solar energy. The morphostructural characteristics were determined by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and the Brunauer-Emmett-Teller method. The attenuated total reflectance Fourier transform infrared spectroscopy confirmed the synthesis of pure and doped nanostructured ZnO. The optical properties were highlighted by UV-VIS Spectroscopy. The research points out that crystallite sizes vary between 37 and 51 nm due to the influence of doping metal. The morphology associated with these particles is predominantly whiskers with elongated parts between 0.18 and 1.4 um. Doping with Fe, Si, Yb, and Ce causes a wider band gap compared to pure ZnO nanoparticles. As solar energy becomes more accessible and efficient, solar-driven synthesis of pure and doped ZnO is poised to be a crucial factor in shaping the future of material science and technology.

Nanomaterials in Medicine: Understanding Cellular Uptake, Localization, and Retention for Enhanced Disease Diagnosis and Therapy

Nanomaterials (NMs) have emerged as promising tools for disease diagnosis and therapy due to their unique physicochemical properties. To maximize the effectiveness and design of NMs-based medical applications, it is essential to comprehend the complex mechanisms of cellular uptake, subcellular localization, and cellular retention. This review illuminates the various pathways that NMs take to get from the extracellular environment to certain intracellular compartments by investigating the various mechanisms that underlie their interaction with cells. The cellular uptake of NMs involves complex interactions with cell membranes, encompassing endocytosis, phagocytosis, and other active transport mechanisms. Unique uptake patterns across cell types highlight the necessity for customized NMs designs. After internalization, NMs move through a variety of intracellular routes that affect where they are located subcellularly. Understanding these pathways is pivotal for enhancing the targeted delivery of therapeutic agents and imaging probes. Furthermore, the cellular retention of NMs plays a critical role in sustained therapeutic efficacy and long-term imaging capabilities. Factors influencing cellular retention include nanoparticle size, surface chemistry, and the cellular microenvironment. Strategies for prolonging cellular retention are discussed, including surface modifications and encapsulation techniques. In conclusion, a comprehensive understanding of the mechanisms governing cellular uptake, subcellular localization, and cellular retention of NMs is essential for advancing their application in disease diagnosis and therapy. This review provides insights into the intricate interplay between NMs and biological systems, offering a foundation for the rational design of next-generation nanomedicines.

Ameliorating Effects of Graphene Oxide on Cadmium Accumulation and Eco-Physiological Characteristics in a Greening Hyperaccumulator (Lonicera japonica Thunb.)

Graphene oxide (GO), as a novel carbon-based nanomaterial (CBN), has been widely applied to every respect of social life due to its unique composite properties. The widespread use of GO inevitably promotes its interaction with heavy metal cadmium (Cd), and influences its functional behavior. However, little information is available on the effects of GO on greening hyperaccumulators under co-occurring Cd. In this study, we chose a typical greening hyperaccumulator (Lonicera japonica Thunb.) to show the effect of GO on Cd accumulation, growth, net photosynthesis rate (Pn), carbon sequestration and oxygen release functions of the plant under Cd stress. The different GO-Cd treatments were set up by (0, 10, 50 and 100 mg L-1) GO and (0, 5 and 25 mg L-1) Cd in solution culture. The maximum rate of Cd accumulation in the roots and shoots of the plant were increased by 10 mg L-1 GO (exposed to 5 mg L-1 Cd), indicating that low-concentration GO (10 mg L-1) combined with low-concentration Cd (5 mg L-1) might stimulate the absorption of Cd by L. japonica. Under GO treatments without Cd, the dry weight of root and shoot biomass, Pn value, carbon sequestration per unit leaf area and oxygen release per unit leaf area all increased in various degrees, especially under 10 mg L-1 GO, were 20.67%, 12.04%, 35% and 28.73% higher than the control. Under GO-Cd treatments, it is observed that the cooperation of low-concentration GO (10 mg L-1) and low-concentration Cd (5 mg L-1) could significantly stimulate Cd accumulation, growth, photosynthesis, carbon sequestration and oxygen release functions of the plant. These results indicated that suitable concentrations of GO could significantly alleviate the effects of Cd on L. japonica, which is helpful for expanding the phytoremediation application of greening hyperaccumulators faced with coexistence with environment of nanomaterials and heavy metals.

Biocompatibility Assessment of Polycaprolactone/Polylactic Acid/Zinc Oxide Nanoparticle Composites under In Vivo Conditions for Biomedical Applications

The increasing demand for non-invasive biocompatible materials in biomedical applications, driven by accidents and diseases like cancer, has led to the development of sustainable biomaterials. Here, we report the synthesis of four block formulations using polycaprolactone (PCL), polylactic acid (PLA), and zinc oxide nanoparticles (ZnO-NPs) for subdermal tissue regeneration. Characterization by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed the composition of the composites. Additionally, the interaction of ZnO-NPs mainly occurred with the C=O groups of PCL occurring at 1724 cm-1, which disappears for F4, as evidenced in the FT-IR analysis. Likewise, this interaction evidenced the decrease in the crystallinity of the composites as they act as crosslinking points between the polymer backbones, inducing gaps between them and weakening the strength of the intermolecular bonds. Thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses confirmed that the ZnO-NPs bind to the carbonyl groups of the polymer, acting as weak points in the polymer backbone from where the different fragmentations occur. Scanning electron microscopy (SEM) showed that the increase in ZnO-NPs facilitated a more compact surface due to the excellent dispersion and homogeneous accumulation between the polymeric chains, facilitating this morphology. The in vivo studies using the nanocomposites demonstrated the degradation/resorption of the blocks in a ZnO-NP-dependant mode. After degradation, collagen fibers (Type I), blood vessels, and inflammatory cells continue the resorption of the implanted material. The results reported here demonstrate the relevance and potential impact of the ZnO-NP-based scaffolds in soft tissue regeneration.

Drug Delivery Application of Functional Nanomaterials Synthesized Using Natural Sources

Nanomaterials (NMs) synthesized from natural sources have been attracting greater attention, due to their intrinsic advantages including biocompatibility, stimuli-responsive property, nontoxicity, cost-effectiveness, and non-immunogenic characteristics in the biological environment. Among various biomedical applications, a breakthrough has been achieved in the development of drug delivery systems (DDS). Biocompatibility is necessary for treating a disease safely without any adverse effects. Some components in DDS respond to the physiological environment, such as pH, temperature, and functional group at the target, which facilitates targeted drug release. NM-based DDS is being applied for treating cancer, arthritis, cardiovascular diseases, and dermal and ophthalmic diseases. Metal nanomaterials and carbon quantum dots are synthesized and stabilized using functional molecules extracted from natural sources. Polymers, mucilage and gums, exosomes, and molecules with biological activities are directly derived from natural sources. In DDS, these functional components have been used as drug carriers, imaging agents, targeting moieties, and super disintegrants. Plant extracts, biowaste, biomass, and microorganisms have been used as the natural source for obtaining these NMs. This review highlights the natural sources, synthesis, and application of metallic materials, polymeric materials, carbon dots, mucilage and gums, and exosomes in DDS. Aside from that, challenges and future perspectives on using natural resources for DDS are also discussed.