Multifunctional gold nanoparticles for diagnosis and therapy of disease

Metallic nanoparticles unveiled: Synthesis, characterization, and their environmental, medicinal, and agricultural applications

Metallic nanoparticles (MNPs) have attracted great interest among scientists and researchers for years due to their unique optical, physiochemical, biological, and magnetic properties. As a result, MNPs have been widely utilized across a variety of scientific fields, including biomedicine, agriculture, electronics, food, cosmetics, and the environment. In this regard, the current review article offers a comprehensive overview of recent studies on the synthesis of MNPs (metal and metal oxide nanoparticles), outlining the benefits and drawbacks of chemical, physical, and biological methods. However, the biological synthesis of MNPs is of great importance considering the biocompatibility and biological activity of certain MNPs. A variety of characterization techniques, including X-ray diffraction, transmission electron microscopy, UV-visible spectroscopy, scanning electron microscopy, dynamic light scattering, atomic force microscopy, Fourier transform infrared spectroscopy, and others, have been discussed in depth to gain deeper insights into the unique structural and spectroscopic properties of MNPs. Furthermore, their unique properties and applications in the fields of medicine, agriculture, and the environment are summarized and deeply discussed. Finally, the main challenges and limitations of MNPs synthesis and applications, as well as their future prospects have also been discussed.

Biotechnological advances in microbial synthesis of gold nanoparticles: Optimizations and applications

This review discusses the eco-friendly and cost-effective biosynthesis of gold nanoparticles (AuNPs) in viable microorganisms, focusing on microbes-mediated AuNP biosynthesis. This process suits agricultural, environmental, and biomedical applications, offering renewable, eco-friendly, non-toxic, sustainable, and time-efficient methods. Microorganisms are increasingly used in green technology, nanotechnology, and RNAi technology, but several microorganisms have not been fully identified and characterized. Bio-nanotechnology offers eco-friendly and sustainable solutions for nanomedicine, with microbe-mediated nanoparticle biosynthesis producing AuNPs with anti-oxidation activity, stability, and biocompatibility. Ultrasmall AuNPs offer rapid distribution, renal clearance, and enhanced permeability in biomedical applications. The review explores nano-size dependent biosynthesis of AuNPs by bacteria, fungi, and viruses revealing their non-toxic, non-genotoxic, and non-oxidative properties on human cells. AuNPs with varying sizes and shapes, from nitrate reductase enzymes, have shown potential as a promising nano-catalyst. The synthesized AuNPs, with negative charge capping molecules, have demonstrated antibacterial activity against drug-resistant Pseudomonas aeruginosa, and Acinetobacter baumannii strains, and were non-toxic to Vero cell lines, indicating potential antibiotic resistance treatments. A green chemical method for the biosynthesis of AuNPs using reducing chloroauric acid and Rhizopus oryzae protein extract has been described, demonstrating excellent stability and strong catalytic activity. AuNPs are eco-friendly, non-toxic, and time-efficient, making them ideal for biomedical applications due to their antioxidant, antidiabetic, and antibacterial properties. In addition to the biomedical application, the review also highlights the role of microbially synthesized AuNPs in sustainable management of plant diseases, and environmental bioremediation.

Enhanced Antibacterial Activity of Levofloxacin with Cucurbit[7]uril-Functionalized Gold Nanoparticles

Bacterial infection is one of the major concerns of the growing society, and over the years, different permutations and combinations of various drugs and adjuvants have been attempted, which led to considerable improvements in the efficacy of the antibacterial drugs. In this regard, macrocyclic receptors such as cyclodextrin, cucurbiturils, calixarene, etc., have played a major role by modulating the drug properties that supplement the antibacterial efficacy. In this study, we have developed cucurbit[7]uril (CB7)-functionalized Au nanoparticles (CB7AuNPs) to modulate the activity of an antibiotic, levofloxacin (LOFL). From the spectroscopic and thermodynamic changes in the LOFL, it has been established that two of the prototropic forms, LOFLH and LOFLH2+, form strong 1:1 host/guest complexes with CB7/CB7AuNP. Both these interactions led to significant upward shifts in the pKa values as well as photostability of LOFL, thereby enhancing the availability of the active form for the antibacterial activity, at the physiological pH. Further, the LOFL uptake has also been established on CB7AuNP, which retained the CB7-LOFL activity at very low concentration of the CB7 host, functionalized on AuNP. Detailed antibacterial studies of LOFL, both as complexed with CB7 and CB7AuNP, were carried out using four food-borne pathogens (Escherichia coli, S. Typhimurium, Bacillus cereus, and Staphylococcus aureus), which revealed a creditable enhancement in the antibacterial property, irrespective of the bacterium strain. These results are quite promising at this stage for the development of drugs customized for multidrug-resistant bacteria.

UV light promoted dihydrolipoic acid and its alanine derivative directed rapid synthesis of stable gold nanoparticles and their catalytic activity

In general, colloidal gold nanoparticles (AuNPs) have been synthesized in heated or boiling water containing HAuCl4 precursor with sodium citrate as reducing stabilizing reagent. Although temperature plays a driving for synthesis of AuNPs, elevated temperature in thermal reduction method causes aggregation of the AuNPs. The preferential, rapid and strong binding of dihydro-lipoic acid and its derivatives on surface of AuNPs via thiol - Au chemistry promote the production of very stable AuNPs. In this study, we have developed citric acid (CA), dihydrolipoic acid (DHLA) and DHLA-Alanine (DHLA-Ala) directed rapid synthesis of ultra-stable AuNPs, DHLA@AuNPs and DHLA-Ala@AuNPs, under the UV (311 nm) irradiation at room temperature (RT: 25 °C) in around 10 min (min). CA is used as a potential reducing agent to expedite both reduction of Au3+ ion and AuNP formation, DHLA and DHLA-Ala act as stabilizing agents by replacing CA molecules on surface of AuNPs in order to produce quite stable AuNP. It is worthy to mention that reduction of Au3+ ion, formation and surface stabilization of AuNPs are consequently occurred in one step. We also investigated how experimental parameters including reaction time and temperature, pH of reaction solution, affect formation of the AuNPs. The effects of salt concentration and storage temperature were studied to show stability of the AuNPs. The synthesized DHLA@AuNPs and DHLA-Alanine@AuNPs were characterized via UV-Vis spectrophotometer (UV-Vis), scanning transmission electron microscope (STEM), dynamic light scattering (DLS) and Zeta potential (ZT) devices. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) was efficiently catalyzed by the AuNPs in the presence of sodium borohydride in aqueous solution.

Review of Gold Nanoparticles: Synthesis, Properties, Shapes, Cellular Uptake, Targeting, Release Mechanisms and Applications in Drug Delivery and Therapy

The remarkable versatility of gold nanoparticles (AuNPs) makes them innovative agents across various fields, including drug delivery, biosensing, catalysis, bioimaging, and vaccine development. This paper provides a detailed review of the important role of AuNPs in drug delivery and therapeutics. We begin by exploring traditional drug delivery systems (DDS), highlighting the role of nanoparticles in revolutionizing drug delivery techniques. We then describe the unique and intriguing properties of AuNPs that make them exceptional for drug delivery. Their shapes, functionalization, drug-loading bonds, targeting mechanisms, release mechanisms, therapeutic effects, and cellular uptake methods are discussed, along with relevant examples from the literature. Lastly, we present the drug delivery applications of AuNPs across various medical domains, including cancer, cardiovascular diseases, ocular diseases, and diabetes, with a focus on in vitro and in vivo cancer research.

Mechanistic understanding of nanoparticle interactions to achieve highly-ordered arrays through self-assembly for sensitive surface-enhanced Raman scattering detection of trace thiram

Over the last few decades, there is increasing worldwide concern over human health risks associated with extensive use of pesticides in agriculture. Developing excellent SERS substrate materials to achieve highly sensitive detection of pesticide residues in the food is very necessary owing to their serious threat to human health through food chains. Self-assembled metallic nanoparticles have been demonstrated to be excellent SERS substrate materials. Hence, alkanethiols-protected gold nanoparticles have been successfully prepared for forming larger-scale two-dimensional monolayer films. These films can be disassembled into a fluid state and re-assembled back to crystallized structure by controlling surface pressure. Further investigations reveal that their self-assembled structures are mainly dependent on the diameter of gold nanoparticles and ligand length. These results suggest that the size ratio of nanoparticle diameter/ligand length within the range of 4.45-2.35 facilitates the formation of highly ordered 2D arrays. Furthermore, these arrays present excellent Surface-Enhanced Raman Scattering performances in the detection of trace thiram, which can cause environmental toxicity to the soil, water, animals and result in severe damage to human health. Therefore, the current study provides an effective way for preparing monodispersed hydrophobic gold nanoparticles and forming highly ordered 2D close-packed SERS substrate materials via self-assembly to detect pesticide residues in food. We believe that, our research provides not only advanced SERS substrate materials for excellent detection performance of thiram in food, but also novel fundamental understandings of self-assembly, manipulation of nanoparticle interactions, and controllable synthesis.

Progress and challenges in bacterial infection theranostics based on functional metal nanoparticles

The rapid proliferation and infection of bacteria, especially multidrug-resistant bacteria, have become a great threat to global public health. Focusing on the emergence of "super drug-resistant bacteria" caused by the abuse of antibiotics and the insufficient and delayed early diagnosis of bacterial diseases, it is of great research significance to develop new technologies and methods for early targeted detection and treatment of bacterial infection. The exceptional effects of metal nanoparticles based on their unique physical and chemical properties make such systems ideal for the detection and treatment of bacterial infection both in vitro and in vivo. Metal nanoparticles also have admirable clinical application prospects due to their broad antibacterial spectrum, various antibacterial mechanisms and excellent biocompatibility. Herein, we summarized the research progress concerning the mechanism of metal nanoparticles in terms of antibacterial activity together with the detection of bacterial. Representative achievements are selected to illustrate the proof-of-concept in vitro and in vivo applications. Based on these observations, we also give a brief discussion on the current problems and perspective outlook of metal nanoparticles in the diagnosis and treatment of bacterial infection.

Effect of cholesterol on nanoparticle translocation across a lipid bilayer

Nanoparticles (NPs) have attracted significant attention as carriers for the delivery of drugs, genes, and macromolecules for biomedical and therapeutic applications. These technologies require NPs to be delivered to the interior of the cell. However, this translocation is unlikely because of the presence of a cell membrane composed of phospholipids, cholesterol, proteins, and glycans. The cell membrane composition can influence its rigidity; thus, membrane composition is a crucial factor in determining the translocation of NPs across the cell membrane. Here, we focus on cholesterol, which is an essential component of biological cell membranes, and investigate NP translocation across membranes containing cholesterol under an applied electric field using a coarse-grained molecular dynamics simulation. We found that NPs could translocate directly across cholesterol-containing membranes without irreversible membrane disruption. This unique translocation was induced by two key phenomena. Before NP translocation, a phospholipid-rich/cholesterol-poor domain was formed at the NP-membrane contact interface. Second, a smaller transmembrane pore was formed in the cholesterol-containing membrane during membrane crossing of the NP. Our findings imply that the delivery of NPs to the cell interior across the cholesterol-containing membrane can be achieved by appropriately controlling the strength of the applied electric field, depending on the cholesterol content in the membrane.

Recent advances in mitochondria-targeting theranostic agents

For its vital role in maintaining cellular activity and survival, mitochondrion is highly involved in various diseases, and several strategies to target mitochondria have been developed for specific imaging and treatment. Among these approaches, theranostic may realize both diagnosis and therapy with one integrated material, benefiting the simplification of treatment process and candidate drug evaluation. A variety of mitochondria-targeting theranostic agents have been designed based on the differential structure and composition of mitochondria, which enable more precise localization within cellular mitochondria at disease sites, facilitating the unveiling of pathological information while concurrently performing therapeutic interventions. Here, progress of mitochondria-targeting theranostic materials reported in recent years along with background information on mitochondria-targeting and therapy have been briefly summarized, determining to deliver updated status and design ideas in this field to readers.

Recent developments in cancer diagnosis and treatment using nanotechnology

The article provides an insightful overview of the pivotal role of nanotechnology in revolutionizing cancer diagnosis and treatment. It discusses the critical importance of nanoparticles in enhancing the accuracy of cancer detection through improved imaging contrast agents and the synthesis of various nanomaterials designed for oncology applications. The review broadly classifies nanoparticles used in therapeutics, including metallic, magnetic, polymeric, and many other types, with an emphasis on their functions in drug delivery systems for targeted cancer therapy. It details targeting mechanisms, including passive and intentional targeting, to maximize treatment efficacy while minimizing side effects. Furthermore, the article addresses the clinical applications of nanomaterials in cancer treatment, highlights prospects, and addresses the challenges of integrating nanotechnology into cancer treatment.

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.

Polymeric curcumin nanospheres for lysozyme aggregation inhibition, antibacterial, and wound healing applications

The present study reports highly stable polymeric nanoparticles comprising curcumin and polyvinylpyrrolidone, and then conjugated with gold nanoparticles, resulting in C-PVP and C-PVP-Au, respectively. The synthesized conjugates C-PVP and C-PVP-Au were investigated for amyloid aggregation inhibition activity, antimicrobial activity, and wound healing applications. The anti-amyloidogenic capacity of nanoconjugates were studied for model protein, hen egg-white lysozyme (HEWL). The ThT binding assay, fibril size measurement, and electron microscopy results revealed that conjugates suppress fibrillogenesis in HEWL. The highest amyloid inhibition activity obtained against C-PVP and C-PVP-Au was 31 μg.mL-1 and 30 μg.mL-1, respectively. The dissociation activity for amyloid aggregation was observed against Q-PVP and Q-PVP-Au at 29 μg.mL-1 and 27 μg.mL-1, respectively. The antibacterial studies show significant efficacy against Escherichia coli (E. coli) in the presence of C-PVP and C-PVP-Au. The substantial antibacterial potential of C-PVP@PVA and C-PVP-Au@PVA membranes shows promising wound healing applications. The PVA membranes with nanoparticles promote the antibacterial activity and wound healing activity in the Drosophila model. C-PVP-Au@PVA membrane healed the wound faster than the C-PVP@PVA, and it can be used for better results in wound healing. Thus, C-PVP-Au and C-PVP have higher bioavailability and stability and can act as multifunctional therapeutic agents for amyloid-related diseases and as wound healing agents. Graphical abstract C-PVP, and C-PVP-Au conjugates for inhibition of HEWL aggregation, antibacterial and wound healing activity.

Better together: nanoscale co-delivery systems of therapeutic agents for high-performance cancer therapy

Combination therapies can enhance the sensitivity of cancer to drugs, lower drug doses, and reduce side effects in cancer treatment. However, differences in the physicochemical properties and pharmacokinetics of different therapeutic agents limit their application. To avoid the above dilemma and achieve accurate control of the synergetic ratio, a nanoscale co-delivery system (NCDS) has emerged as a prospective tool for combined therapy in cancer treatment, which is increasingly being used to co-load different therapeutic agents. In this study, we have summarized the mechanisms of therapeutic agents in combination for cancer therapy, nanoscale carriers for co-delivery, drug-loading strategies, and controlled/targeted co-delivery systems, aiming to give a general picture of these powerful approaches for future NCDS research studies.

Radiolabeled multi-layered coated gold nanoparticles as potential biocompatible PET/SPECT tracers

The demand for tailored, disease-adapted, and easily accessible radiopharmaceuticals is one of the most persistent challenges in nuclear imaging precision medicine. The aim of this work was to develop two multimodal radiotracers applicable for both SPECT and PET techniques, which consist of a gold nanoparticle core, a shell involved in radioisotope entrapment, peripherally placed targeting molecules, and biocompatibilizing polymeric sequences. Shell decoration with glucosamine units located in sterically hindered molecular environments is expected to result in nanoparticle accumulation in high-glucose-consuming areas. Gold cores were synthesized using the Turkevich method, followed by citrate substitution with linear PEG α,ω-functionalized with thiol and amine groups. The free amine groups facilitated the binding of branched polyethyleneimine through an epoxy ring-opening reaction by using PEG α,ω-diglycidyl ether as a linker. Afterwards, the glucose-PEG-epoxy prepolymer has been grafted onto the surface of AuPEG-PEI conjugates. Finally, the AuPEG-PEI-GA conjugates were radiolabeled with 99mTc or 68Ga. Instant thin-layer chromatography was used to evaluate the radiolabeling yield. The biocompatibility of non-labeled and 99mTc or 68Ga labeled nanoparticles was assessed on normal fibroblasts. The 99mTc complexes remained stable for over 22 hours, while the 68Ga containing ones revealed a slight decrease in stability after 1 hour.

Antimicrobial peptide mimetic minimalistic approach leads to very short peptide amphiphiles-gold nanostructures for potent antibacterial activity

Strategically controlling concentrations of lipid-conjugated L-tryptophan (vsPA) guides the self-assembly of nanostructures, transitioning from nanorods to fibres and culminating in spherical shapes. The resulting Peptide-Au hybrids, exhibiting size-controlled 1D, 2D, and 3D nanostructures, show potential in antibacterial applications. Their high biocompatibility, favourable surface area-to-volume ratio, and plasmonic properties contribute to their effectiveness against clinically relevant bacteria. This controlled approach not only yields diverse nanostructures but also holds promise for applications in antibacterial therapeutics.

Inhibition of the thioredoxin system for radiosensitization therapy of cancer

Radiotherapy (RT) stands as a cornerstone in the clinical armamentarium against various cancers due to its proven efficacy. However, the intrinsic radiation resistance exhibited by cancer cells, coupled with the adverse effects of RT on normal tissues, often compromises its therapeutic potential and leads to unwanted side effects. This comprehensive review aims to consolidate our understanding of how radiosensitizers inhibit the thioredoxin (Trx) system in cellular contexts. Notable radiosensitizers, including gold nanoparticles (GNPs), gold triethylphosphine cyanide ([Au(SCN) (PEt3)]), auranofin, ceria nanoparticles (CONPs), curcumin and its derivatives, piperlongamide, indolequinone derivatives, micheliolide, motexafin gadolinium, and ethane selenide selenidazole derivatives (SeDs), are meticulously elucidated in terms of their applications in radiotherapy. In this review, the sensitization mechanisms and the current research progress of these radiosensitizers are discussed in detail, with the overall aim of providing valuable insights for the judicious application of Trx system inhibitors in the field of cancer radiosensitization therapy.

Preparation of a novel metallothionein-AuNP composite material by genetic modification and AuS covalent combination

Metallothionein (MTs) can be used in the prevention and treatment of tumors and diabetes due to its antioxidant properties. However, it is necessary to solve its non-transmembrane properties and further improve its antioxidant activity, increase its fluorescence visualization and enhance its stability to meet practical applications in the biomedical field. Here, we report the preparation of a novel metallothionein-AuNP composite material with high transmembrane ability, fluorescence visualization, antioxidant activity, and stability by genetic modification (introducing transduction peptide TAT, fluorescence tag GFP and increasing sulfydryl groups) and immobilization technology (covalently bonding with AuNPs). The transmembrane activity of modified proteins was verified by immunofluorescence. Increasing the sulfhydryl content within a certain range can enhance the antioxidant activity of the protein. In addition, GFP were used to further simplify the imaging of the metallothionein-AuNP composite in cells. XPS results indicated that AuNPs can immobilize metallothionein through AuS covalent bonds. TGA characterization and degradation experiments showed that thermal and degradation stability of the immobilized material was significantly improved. This work provides new ideas to construct metallothionein composites with high transmembrane ability, antioxidant activity, fluorescence visualization and stability to meet novel applications in the biomedical field.

Engineered smart materials for RNA based molecular therapy to treat Glioblastoma

Glioblastoma (GBM) is an aggressive malignancy of the central nervous system (CNS) that remains incurable despite the multitude of improvements in cancer therapeutics. The conventional chemo and radiotherapy post-surgery have only been able to improve the prognosis slightly; however, the development of resistance and/or tumor recurrence is almost inevitable. There is a pressing need for adjuvant molecular therapies that can successfully and efficiently block tumor progression. During the last few decades, non-coding RNAs (ncRNAs) have emerged as key players in regulating various hallmarks of cancer including that of GBM. The levels of many ncRNAs are dysregulated in cancer, and ectopic modulation of their levels by delivering antagonists or overexpression constructs could serve as an attractive option for cancer therapy. The therapeutic potential of several types of ncRNAs, including miRNAs, lncRNAs, and circRNAs, has been validated in both in vitro and in vivo models of GBM. However, the delivery of these RNA-based therapeutics is highly challenging, especially to the tumors of the brain as the blood-brain barrier (BBB) poses as a major obstacle, among others. Also, since RNA is extremely fragile in nature, careful considerations must be met while designing a delivery agent. In this review we have shed light on how ncRNA therapy can overcome the limitations of its predecessor conventional therapy with an emphasis on smart nanomaterials that can aide in the safe and targeted delivery of nucleic acids to treat GBM. Additionally, critical gaps that currently exist for successful transition from viral to non-viral vector delivery systems have been identified. Finally, we have provided a perspective on the future directions, potential pathways, and target areas for achieving rapid clinical translation of, RNA-based macromolecular therapy to advance the effective treatment of GBM and other related diseases.

Surface-Tailored Nanoplatform for the Diagnosis and Management of Stroke: Current Strategies and Future Outlook

Stroke accounts for one of the top leading reasons for neurological mortality and morbidity around the globe. Both ischemic and hemorrhagic strokes lead to local hypoxia and are brought about by the occlusion or rupturing of the blood vessels. The events taking place after the onset of a stroke include membrane ion pump failure, calcium and glutamate-mediated excitotoxicity, increased ROS production causing DNA damage, mitochondrial dysfunction, oxidative stress, development of brain edema, and microvascular dysfunction. To date, tissue plasminogen activator (tPA) therapy and mechanical removal of blood clots are the only clinically available stroke therapies, approved by Food and Drug Administration (FDA). But because of the narrow therapeutic window of around 4.5 h for tPA therapy and complications like systemic bleeding and anaphylaxis, more clinical trials are ongoing in the same field. Therefore, using nanocarriers with diverse physicochemical properties is a promising strategy in treating and diagnosing stroke as they can efficiently bypass the tight blood-brain barrier (BBB) through mechanisms like receptor-mediated transcytosis and help achieve controlled and targeted drug delivery. In this review, we will mainly focus on the pathophysiology of stroke, BBB alterations following stroke, strategies to target BBB for stroke therapies, different types of nanocarriers currently being used for therapeutic intervention of stroke, and biomarkers as well as imaging techniques used for the detection and diagnosis of stroke.

The Apoptotic, Oxidative and Histological Changes Induced by Different Diameters of Sphere Gold Nanoparticles (GNPs) with Special Emphasis on the Hepatoprotective Role of Quercetin

Purpose

Gold nanoparticles (GNPs) as pharmaceutical and drug delivery tools exhibited harmful effects on human health and other living species. Quercetin (Qur) reveals various pharmacological effects specially antioxidant, anti-inflammatory and antiapoptotic. This study is directed to investigate hepatotoxicity of GNPs, in addition, to assess the impact of Qur in mitigating the toxicological effects of GNPs.

Methods

Groups of rats were treated with or without sphere GNPs (10, 20 and 50 nm) and Qur (200 mg/kg b.wt.). Blood and liver samples from euthanized rats were subjected to biochemical, hematological, histopathological, and immunohistochemical investigations.

Results

In comparison with 20 and 50 nm treated groups, the 10 nm GNPs significantly increased serum hepatic enzymes, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and bilirubin. These 10 nm GNPs were associated with oxidative stress and markedly decreased antioxidant enzymes: catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD). Immunohistochemically, 10 nm GNPs expressed intense positive signals in nuclei of hepatocytes when stained with anti-caspase-3 antibody confirming extensive apoptosis. Pre-cotreatment with Qur decreased all tested hepatic enzymes and increased serum level of antioxidant enzymes compared to 10 nm GNPs. Qur treatment strongly exhibited anti-Ki67 antibody (proliferative marker) indicating high proliferation of hepatic parenchyma. Histopathologically, 10 nm GNPs revealed diffuse hydropic degenerations, severe sinusoidal congestion, coagulative necrosis, sever steatosis and diffuse hemosiderosis within the hepatic parenchyma. Qur treatment ameliorated most of these pathological effects.

Conclusion

The smaller diameters of GNPs induce potential oxidative stress, cytotoxic, and apoptotic effects in hepatic tissues rather than larger ones. In addition, Qur demonstrated a significant prophylactic role against hepatotoxicity of GNPs.

Gold Nanoparticles in Neurological Diseases: A Review of Neuroprotection

This review explores the diverse applications of gold nanoparticles (AuNPs) in neurological diseases, with a specific focus on Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The introduction highlights the pivotal role of neuroinflammation in these disorders and introduces the unique properties of AuNPs. The review's core examines the mechanisms by which AuNPs exert neuroprotection and anti-neuro-inflammatory effects, elucidating various pathways through which they manifest these properties. The potential therapeutic applications of AuNPs in AD are discussed, shedding light on promising avenues for therapy. This review also explores the prospects of utilizing AuNPs in PD interventions, presenting a hopeful outlook for future treatments. Additionally, the review delves into the potential of AuNPs in providing neuroprotection after strokes, emphasizing their significance in mitigating cerebrovascular accidents' aftermath. Experimental findings from cellular and animal models are consolidated to provide a comprehensive overview of AuNPs' effectiveness, offering insights into their impact at both the cellular and in vivo levels. This review enhances our understanding of AuNPs' applications in neurological diseases and lays the groundwork for innovative therapeutic strategies in neurology.

Harnessing the power of gold: advancements in anticancer gold complexes and their functionalized nanoparticles

Cancer poses a formidable challenge, necessitating improved treatment strategies. Metal-based drugs and nanotechnology offer new hope in this battle. Versatile gold complexes and functionalized gold nanoparticles exhibit unique properties like biologically inert behaviour, outstanding light absorption, and heat-conversion abilities. These nanoparticles can be finely tuned for drug delivery, enabling precise and targeted cancer therapy. Their exceptional drug-loading capacity and low toxicity, stemming from excellent stability, biocompatibility, and customizable shapes, make them a promising option for enhancing cancer treatment outcomes and improving diagnostic imaging. Leveraging these attributes, researchers can design more effective and targeted cancer therapeutics. The potential of functionalized gold nanoparticles to advance cancer treatment and diagnostics holds a promising avenue for further exploration and development in the fight against cancer. This review article delves into the finely tuned attributes of functionalized gold nanoparticles, unveiling their potential for application in drug delivery for precise and targeted cancer therapy.

Radioactive gold nanoparticles coated with BSA: A promising approach for prostate cancer treatment

Background: Nanotechnology has revolutionized medicine, especially in oncological treatments. Gold nanoparticles (AuNPs) stand out as an innovative alternative due to their biocompatibility, potential for surface modification, and effectiveness in radiotherapeutic techniques. Given that prostate cancer ranks as one of the leading malignancies among men, there's a pressing need to investigate new therapeutic approaches. Methods: AuNPs coated with bovine serum albumin (BSA) were synthesized and their cytotoxicity was assessed against prostate tumor cell lines (LNCaP and PC-3), healthy prostate cells (RWPE-1), and endothelial control cells (HUVEC) using the MTS/PMS assay. For in vivo studies, BALB/C Nude mice were employed to gauge the therapeutic efficacy, biodistribution, and hematological implications post-treatment with BSA-coated AuNPs. Results: The BSA-coated AuNPs exhibited cytotoxic potential against PC-3 and LNCaP lines, while interactions with RWPE-1 and HUVEC remain subjects for further scrutiny. Within animal models, a diverse therapeutic response was observed, with certain instances indicating complete tumor regression. Biodistribution data emphasized the nanoparticles' affinity towards particular organs, and the majority of hematological indicators aligned with normative standards. Conclusions: BSA-coated AuNPs manifest substantial promise as therapeutic tools in treating prostate cancer. The present research not only accentuates the nanoparticles' efficacy but also stresses the imperative of optimization to ascertain both selectivity and safety. Such findings illuminate a promising trajectory for avant-garde therapeutic modalities, holding substantial implications for public health advancements.

Photochemical outcomes triggered by gold shell-isolated nanorods on bioinspired nanoarchitectonics for bacterial membranes

Boosted by the indiscriminate use of antibiotics, multidrug-resistance (MDR) demands new strategies to combat bacterial infections, such as photothermal therapy (PTT) based on plasmonic nanostructures. PTT efficiency relies on photoinduced damage caused to the bacterial machinery, for which nanostructure incorporation into the cell envelope is key. Herein, we shall unveil the binding and photochemical mechanisms of gold shell-isolated nanorods (AuSHINRs) on bioinspired bacterial membranes assembled as Langmuir and Langmuir-Schaefer (LS) monolayers of DOPE, Lysyl-PG, DOPG and CL. AuSHINRs incorporation expanded the isotherms, with stronger effect on the anionic DOPG and CL. Indeed, FTIR of LS films revealed more modifications for DOPG and CL owing to stronger attractive electrostatic interactions between anionic phosphates and the positively charged AuSHINRs, while electrostatic repulsions with the cationic ethanolamine (DOPE) and lysyl (Lysyl-PG) polar groups might have weakened their interactions with AuSHINRs. No statistical difference was observed in the surface area of irradiated DOPE and Lysyl-PG monolayers on AuSHINRs, which is evidence of the restricted nanostructures insertion. In contrast, irradiated DOPG monolayer on AuSHINRs decreased 4.0 % in surface area, while irradiated CL monolayer increased 3.7 %. Such results agree with oxidative reactions prompted by ROS generated by AuSHINRs photoactivation. The deepest AuSHINRs insertion into DOPG may have favored chain cleavage while hydroperoxidation is the mostly like outcome in CL, where AuSHINRs are surrounding the polar groups. Furthermore, preliminary experiments on Escherichia coli culture demonstrated that the electrostatic interactions with AuSHINRs do not inhibit bacterial growth, but the photoinduced effects are highly toxic, resulting in microbial inactivation.

Functionalized Gold Nanoparticles Suppress the Proliferation of Human Lung Alveolar Adenocarcinoma Cells by Deubiquitinating Enzymes Inhibition

Functionalized gold nanoparticles (AuNPs) are widely used in therapeutic applications, but little is known regarding the impact of their surface functionalization in the process of toxicity against cancer cells. This study investigates the anticancer effects of 5 nm spherical AuNPs functionalized with tannate, citrate, and PVP on deubiquitinating enzymes (DUBs) in human lung alveolar adenocarcinoma (A549) cells. Our findings show that functionalized AuNPs reduce the cell viability in a concentration- and time-dependent manner as measured by modified lactate dehydrogenase (mLDH) and 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assays. An increased generation of intracellular reactive oxygen species (ROS) and depletion of glutathione (GSH/GSSG) ratio was observed with the highest AuNP concentration of 10 μg/mL. The expression of DUBs such as ubiquitin specific proteases (USP7, USP8, and USP10) was slightly inhibited when treated with concentrations above 2.5 μg/mL. Moreover, functionalized AuNPs showed an inhibitory effect on protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) and wingless-related integration site (Wnt) signaling proteins, and this could further trigger mitochondrial related-apoptosis by the upregulation of caspase-3, caspase-9, and PARP in A549 cells. Furthermore, our study shows a mechanistic understanding of how functionalized AuNPs inhibit the DUBs, consequently suppressing cell proliferation, and can be modulated as an approach toward anticancer therapy. The study also warrants the need for future work to investigate the effect of functionalized AuNPs on DUB on other cancer cell lines both in vitro and in vivo.

Molecular Surface Quantification of Multifunctionalized Gold Nanoparticles Using UV-Visible Absorption Spectroscopy Deconvolution

Multifunctional gold nanoparticles (AuNPs) are of great interest, owing to their vast potential for use in many areas including sensing, imaging, delivery, and medicine. A key factor in determining the biological activity of multifunctional AuNPs is the quantification of surface conjugated molecules. There has been a lack of accurate methods to determine this for multifunctionalized AuNPs. We address this limitation by using a new method based on the deconvolution and Levenberg-Marquardt algorithm fitting of UV-visible absorption spectrum to calculate the precise concentration and number of cytochrome C (Cyt C) and zinc porphyrin (Zn Porph) bound to each multifunctional AuNP. Dynamic light scattering (DLS) and zeta potential measurements were used to confirm the functionalization of AuNPs with Cyt C and Zn Porph. Transmission electron microscopy (TEM) was used in conjunction with UV-visible absorption spectroscopy and DLS to identify the AuNP size and confirm that no aggregation had taken place after functionalization. Despite the overlapping absorption bands of Cyt C and Zn Porph, this method was able to reveal a precise concentration and number of Cyt C and Zn Porph molecules attached per AuNP. Furthermore, using this method, we were able to identify unconjugated molecules, suggesting the need for further purification of the sample. This guide provides a simple and effective method to quickly quantify molecules bound to AuNPs, giving users valuable information, especially for applications in drug delivery and biosensors.

Intranasal Nanotransferosomal Gel for Quercetin Brain Targeting: I. Optimization, Characterization, Brain Localization, and Cytotoxic Studies

Numerous neurological disorders have a pathophysiology that involves an increase in free radical production in the brain. Quercetin (QER) is a nutraceutical compound that shields the brain against oxidative stress-induced neurodegeneration. Nonetheless, its low oral bioavailability diminishes brain delivery. Therefore, the current study aimed to formulate QER-loaded transferosomal nanovesicles (QER-TFS) in situ gel for QER brain delivery via the intranasal route. This study explored the impacts of lipid amount, edge activator (EA) amount, and EA type on vesicle diameter, entrapment, and cumulative amount permeated through nasal mucosa (24 h). The optimum formulation was then integrated into a thermosensitive gel after its physical and morphological characteristics were assessed. Assessments of the optimized QER-TFS showed nanometric vesicles (171.4 ± 3.4 nm) with spherical shapes and adequate entrapment efficiency (78.2 ± 2.8%). The results of short-term stability and high zeta potential value (-32.6 ± 1.4 mV) of QER-TFS confirmed their high stability. Compared with the QER solution, the optimized QER-TFS in situ gel formulation exhibited sustained release behavior and augmented nasal mucosa permeability. CT scanning of rat brains demonstrated the buildup of gold nanoparticles (GNPs) in the brains of all treatment groups, with a greater level of GNPs noted in the rats given the transferosomal gel. Additionally, in vitro studies on PCS-200-014 cells revealed minimal cytotoxicity of QER-TFS in situ gel. Based on these results, the developed transferosomal nanovesicles may be a suitable nanocarrier for QER brain targeting through the intranasal route.

An X-ray activatable gold nanorod encapsulated liposome delivery system for mitochondria-targeted photodynamic therapy (PDT)

In this work, we developed a mitochondria-targeted nanomaterial for neoadjuvant X-ray-triggered photodynamic therapy of rectal cancer. Herein, we designed a biodegradable liposome incorporating a photosensitizer, verteporfin, to generate X-ray-induced reactive oxygen species, gold nanorods as radiation enhancers, and triphenylphosphonium as the mitochondrial targeting moiety. The average size of the nanocarrier was about 150 nm. Due to the synergetic effect between X-ray and a combination of verteporfin and gold nanorods, as well as precise site-targeted TPP-modified liposomal nanocarriers, our nanoconjugates generated sufficient cytotoxic singlet oxygen within the mitochondria under X-ray irradiation, triggering the loss of membrane potential and mitochondria-related apoptosis of cancer cells.

Effect of Physiological Fluid on the Photothermal Properties of Gold Nanostructured

Colloidal gold particles have been extensively studied for their potential in hyperthermia treatment due to their ability to become excited in the presence of an external laser. However, their light-to-heat efficiency is affected by the physiologic environment. In this study, we aimed to evaluate the ability of gold sphere, rod, and star-shaped colloids to elevate the temperature of blood plasma and breast cancer-simulated fluid under laser stimulation. Additionally, the dependence of optical properties and colloid stability of gold nanostructures with physiological medium, particle shape, and coating was determined. The light-to-heat efficiency of the gold particle is shape-dependent. The light-to-heat conversion efficiency of a star-shaped colloid is 36% higher than that of sphere-shaped colloids. However, the raised temperature of the surrounding medium is the lowest in the star-shaped colloid. When gold nanostructures are exited with a laser stimulation in a physiological fluid, the ions/cations attach to the surface of the gold particles, resulting in colloidal instability, which limits electron oscillation and diminishes the energy generated by the plasmonic excitation. Fluorescein (Fl) and polyethylene glycol (PEG) attached to gold spheres enhances their colloidal stability and light-to-heat efficiency; post-treatment, they remand their optical properties.

Endotracheal nebulization of gold nanoparticles for noninvasive pulmonary drug delivery

Background & aims: Gold nanoparticles (AuNPs) are useful tools for noninvasive drug delivery. AuNP nebulization has shown poor deposition results, and AuNP tracking postadministration has involved methods inapplicable to clinical settings. The authors propose an intratracheal delivery method for minimal AuNP loss and computed tomography scans for noninvasive tracking. Materials & methods: Through high-frequency and directed nebulization postendotracheal intubation, the authors treated rats with AuNPs. Results & conclusion: The study showed a dose-dependent and bilateral distribution of AuNPs causing no short-term distress to the animal or risk of airway inflammation. The study demonstrated that AuNPs do not deposit in abdominal organs and show targeted delivery to human lung fibroblasts, offering a specific and noninvasive strategy for respiratory diseases requiring long-term therapies.

Colorimetric Sensing of Gram-Negative and Gram-Positive Bacteria Using 4-Mercaptophenylboronic Acid-Functionalized Gold Nanoparticles in the Presence of Polyethylene Glycol

Gold nanoparticles (GNPs) have been used as detection probes for rapid and sensitive detection of various analytes, including bacteria. Here, we demonstrate a simple strategy for bacterial detection using GNPs functionalized with 4-mercaptophenylboronic acid (4-MPBA). 4-MPBA can interact with peptidoglycan or lipopolysaccharides present in bacterial organelles. After the addition of a high concentration of sodium hydroxide (NaOH), the functionalization of the surface of 50 nm GNPs with 4-MPBA (4-MPBA@GNPs) in the presence of polyethylene glycol results in a color change because of the aggregation of 4-MPBA@GNPs. This color change is dependent on the amount of bacteria present in the tested samples. Escherichia coli (E. coli) K-12 and Staphylococcus aureus (S. aureus) are used as Gram-negative and Gram-positive bacterial models, respectively. The color change can be detected within an hour by the naked eye. A linear relationship is observed between bacterial concentrations and the absorbance intensity at 533 nm; R ² values of 0.9152 and 0.8185 are obtained for E. coli K-12 and S. aureus, respectively. The limit of detection of E. coli K-12 is ∼2.38 × 10² CFU mL^-1 and that of S. aureus is ∼4.77 × 10³ CFU mL^-1. This study provides a promising approach for the rapid detection of target Gram-negative and Gram-positive bacteria.

An Insight Into the Physicochemical Properties of Gold Nanoparticles in Relation to Their Clinical and Diagnostic Applications

The ease of formulation and surface modification of gold nanoparticles (AuNPs) by ligands, greater biocompatibility, non-cytotoxicity, and excellent optical properties are the characteristics that necessitate their application in clinical and genomic research. Not only that, but the extensive synthetic chemistry of AuNPs also offers precise control over physicochemical and optical properties owing to the inert, biocompatible, and non-toxic nature of the inner gold core. Another important property of AuNPs involves their incorporation into larger structures, including liposomes or polymeric materials, thereby increasing their capability of drug delivery in concurrent therapy and imaging labels for enhanced diagnostic applications. AuNPs are endowed with physical properties that suggest their use as adjuvants for radiotherapy and bio-imaging and in computed tomography (CT) scans, diagnostic systems, and therapy. Thus, these features strongly endorse the AuNPs in thrust areas of biomedical fields. The diverse properties of gold nanoparticles (AuNPs) have made them promising candidates in biomedical fields, including in the development of theranostics, which encompasses using these gold nanoparticles for both diagnosis and therapy simultaneously. To appreciate these and related applications, a need arises to review the basic principles and multifunctional attributes of AuNPs in relation to their advances in imaging, therapy, and diagnostics.

Nanotechnology in Cancer Diagnosis and Treatment

Traditional cancer diagnosis has been aided by the application of nanoparticles (NPs), which have made the process easier and faster. NPs possess exceptional properties such as a larger surface area, higher volume proportion, and better targeting capabilities. Additionally, their low toxic effect on healthy cells enhances their bioavailability and t-half by allowing them to functionally penetrate the fenestration of epithelium and tissues. These particles have attracted attention in multidisciplinary areas, making them the most promising materials in many biomedical applications, especially in the treatment and diagnosis of various diseases. Today, many drugs are presented or coated with nanoparticles for the direct targeting of tumors or diseased organs without harming normal tissues/cells. Many types of nanoparticles, such as metallic, magnetic, polymeric, metal oxide, quantum dots, graphene, fullerene, liposomes, carbon nanotubes, and dendrimers, have potential applications in cancer treatment and diagnosis. In many studies, nanoparticles have been reported to show intrinsic anticancer activity due to their antioxidant action and cause an inhibitory effect on the growth of tumors. Moreover, nanoparticles can facilitate the controlled release of drugs and increase drug release efficiency with fewer side effects. Nanomaterials such as microbubbles are used as molecular imaging agents for ultrasound imaging. This review discusses the various types of nanoparticles that are commonly used in cancer diagnosis and treatment.

Immunomodulatory nanosystems: An emerging strategy to combat viral infections

The viral infection spreads with the assistance of a host. Traditional antiviral therapies cannot provide long-term immunity against emerging and drug-resistant viral infections. Immunotherapy has evolved as an efficient approach for disease prevention and treatment, which include cancer, infections, inflammatory, and immune disorders. Immunomodulatory nanosystems can dramatically enhance therapeutic outcomes by combating many therapeutic challenges, such as poor immune stimulation and off-target adverse effects. Recently, immunomodulatory nanosystems have emerged as a potent antiviral strategy to intercept viral infections effectively. This review introduces major viral infections with their primary symptoms, route of transmission & targeted organ, and different stages of the viral life cycle with respective traditional blockers. The IMNs have an exceptional capacity for precisely modulating the immune system for therapeutic applications. The nano sized immunomodulatory systems permit the immune cells to interact with infectious agents enhancing lymphatic drainage and endocytosis by the over-reactive immune cells in the infected areas. Immune cells that can be modulated upon viral infection via various immunomodulatory nanosystems have been discussed. Advancement in theranostics can yield an accurate diagnosis, adequate treatment, and real-time screening of viral infections. Nanosystem-based drug delivery can continue to thrive in diagnosing, treating, and preventing viral infections. The curative medicine for remerging and drug-resistant viruses remains challenging, though certain systems have expanded our perception and initiated a new research domain in antiviral treatments.

Concentration-dependent photothermal conversion efficiency of gold nanoparticles under near-infrared laser and broadband irradiation

The photothermal conversion efficiency of gold different nanoparticles (GNPs) in different concentrations (1.25-20 µg/mL) and at different irradiation intensities of near-infrared (NIR) broadband and NIR laser irradiation is evaluated. Results show that for a concentration of 20.0 µg/mL, 40 nm gold nanospheres, 25 × 47 nm gold nanorods (GNRs), and 10 × 41 nm GNRs show a 4-110% higher photothermal conversion efficiency under NIR broadband irradiation than under NIR laser irradiation. Broadband irradiation seems suitable to attain higher efficiencies for the nanoparticles whose absorption wavelength is different from the irradiation wavelength. Lower concentrations (1.25-5 µg/mL) of such nanoparticles show 2-3 times higher efficiency under NIR broadband irradiation. For GNRs of sizes 10 × 38 nm and 10 × 41 nm, the different concentrations show almost equal efficiencies for NIR laser and broadband irradiation. On increasing the irradiation power from 0.3 to 0.5 W, for 10 × 41 nm GNRs in the concentration range of 2.5-20.0 µg/mL, NIR laser irradiation results in 5-32% higher efficiencies, while NIR broadband irradiation leads to a 6-11% increase in efficiency. Under NIR laser irradiation, the photothermal conversion efficiency increases with an increase in optical power. The findings will facilitate the selection of nanoparticle concentrations, irradiation source, and irradiation power for a variety of plasmonic photothermal applications.

Nanotechnology-Inspired Extracellular Vesicles Theranostics for Diagnosis and Therapy of Central Nervous System Diseases

Shuttling various bioactive substances across the blood-brain barrier (BBB) bidirectionally, extracellular vesicles (EVs) have been opening new frontiers for the diagnosis and therapy of central nervous system (CNS) diseases. However, clinical translation of EV-based theranostics remains challenging due to difficulties in effective EV engineering for superior imaging/therapeutic potential, ultrasensitive EV detection for small sample volume, as well as scale-up and standardized EV production. In the past decade, continuous advancement in nanotechnology provided extensive concepts and strategies for EV engineering and analysis, which inspired the application of EVs for CNS diseases. Here we will review the existing types of EV-nanomaterial hybrid systems with improved diagnostic and therapeutic efficacy for CNS diseases. A summary of recent progress in the incorporation of nanomaterials and nanostructures in EV production, separation, and analysis will also be provided. Moreover, the convergence between nanotechnology and microfluidics for integrated EV engineering and liquid biopsy of CNS diseases will be discussed.

Chloroplast-boosted photodynamic therapy for effective drug-resistant bacteria killing and biofilm ablation

Due to the misuse of various antibiotics, the problem of bacterial resistance has become more serious worldwide, and the associated diseases have significantly increased the medical burden of society. Antimicrobial photodynamic therapy (PDT) has received widespread attention because of its safety, efficiency, and facile implementation. Here, we report an oxygen-supply antibacterial agent (Ce6@CS/CP), which could enhance the efficacy of antibacterial PDT via photosynthesis of O₂. Ce6@CS/CP displayed a robust interaction with bacteria, hence facilitating the delivery efficiency of Ce6. In vitro experiments demonstrated that the photodynamic bactericidal potency of Ce6@CS/CP was remarkably greater than that of free Ce6. Furthermore, Ce6@CS/CP also exhibited superior significant antibiofilm activity to free Ce6. As a live oxygen-supply antibacterial agent, Ce6@CS/CP possesses excellent bacteria delivery ability of Ce6 and could enhance the potency of antibacterial PDT by photosynthesis, offering a new strategy for fighting against drug-resistant bacteria.

Assessing the bio-stability of microRNA-146a conjugated nanoparticles via electroanalysis

The number of diabetics is increasing worldwide and is associated with significant instances of clinical morbidity. Increased amounts of reactive oxygen species (ROS) and proinflammatory cytokines are associated with the pathogenesis of diabetic wounds and result in a significant delay in healing. Our previous studies have shown the ability of a cerium oxide nanoparticle (CNP) formulation conjugated with the anti-inflammatory microRNA miR146a (CNP-miR146a) to enhance the healing of diabetic wounds. The observed therapeutic activity exceeded the combined efficacies of the individual conjugate components (CNPs and miR146a alone), suggesting a synergistic effect. The current study evaluates whether the previously observed enhanced activity arises from increased agent delivery (simple nanocarrier activity) or is specific to the CNP-miR146a formulation (functional, bio-active nanomaterial). Comparison with miR146a conjugated gold (bioactive, metal) and silica (bioinert, oxide) nanoparticles (AuNPs and SiO₂NPs) was performed in the presence of H₂O₂, as an analogue to the high levels of ROS present in the diabetic wound environment. Electrochemical studies, materials characterization, and chemical assays showed limited interaction of AuNP-miR146a with H₂O₂ and instability of SiO₂NP-miR146a over time. In contrast, and in support of our prior results, CNP-miR146a displayed chemical stability and persistent ROS scavenging ability. Furthermore, it was determined that CNPs protect miR146a from oxidative damage under prolonged exposure to H₂O₂, whereas AuNPs and SiO₂NPs were shown to be ineffective. Overall, these results reinforce the ability of CNPs to stabilize and protect miRNA while exhibiting robust antioxidant properties, suggesting that therapeutic activity observed in related earlier studies is not limited to a facile nanocarrier function.

Chitosan-Coated Polymeric Silver and Gold Nanoparticles: Biosynthesis, Characterization and Potential Antibacterial Applications: A Review

Biosynthesized metal nanoparticles, especially silver and gold nanoparticles, and their conjugates with biopolymers have immense potential in various fields of science due to their enormous applications, including biomedical applications. Polymeric nanoparticles are particles of small sizes from 1 nm to 1000 nm. Among different polymeric nanoparticles, chitosan-coated silver and gold nanoparticles have gained significant interest from researchers due to their various biomedical applications, such as anti-cancer, antibacterial, antiviral, antifungal, anti-inflammatory technologies, as well as targeted drug delivery, etc. Multidrug-resistant pathogenic bacteria have become a serious threat to public health day by day. Novel, effective, and safe antibacterial agents are required to control these multidrug-resistant pathogenic microorganisms. Chitosan-coated silver and gold nanoparticles could be effective and safe agents for controlling these pathogens. It is proven that both chitosan and silver or gold nanoparticles have strong antibacterial activity. By the conjugation of biopolymer chitosan with silver or gold nanoparticles, the stability and antibacterial efficacy against multidrug-resistant pathogenic bacteria will be increased significantly, as well as their toxicity in humans being decreased. In recent years, chitosan-coated silver and gold nanoparticles have been increasingly investigated due to their potential applications in nanomedicine. This review discusses the biologically facile, rapid, and ecofriendly synthesis of chitosan-coated silver and gold nanoparticles; their characterization; and potential antibacterial applications against multidrug-resistant pathogenic bacteria.

Assembling Biocompatible Polymers on Gold Nanoparticles: Toward a Rational Design of Particle Shape by Molecular Dynamics

Gold nanoparticles (AuNPs) have received great attention in a number of fields ranging from the energy sector to biomedical applications. As far as the latter is concerned, due to rapid renal clearance and a short lifetime in blood, AuNPs are often encapsulated in a poly(lactic-co-glycolic acid) (PLGA) matrix owing to its biocompatibility and biodegradability. A better understanding of the PLGA polymers on the AuNP surface is crucial to improve and optimize the above encapsulation process. In this study, we combine a number of computational approaches to explore the adsorption mechanisms of PLGA oligomers on a Au crystalline NP and to rationalize the PLGA coating process toward a more efficient design of the NP shape. Atomistic simulations supported by a recently developed unsupervised machine learning scheme show the temporal evolution and behavior of PLGA clusterization by tuning the oligomer concentration in aqueous solutions. Then, a detailed surface coverage analysis coupled with free energy landscape calculations sheds light on the anisotropic nature of PLGA adsorption onto the AuNP. Our results prove that the NP shape and topology may address and privilege specific sites of adsorption, such as the Au {1 1 1} crystal planes in selected NP samples. The modeling-based investigation suggested in this article offers a solid platform to guide the design of coated NPs.

Development of gold nanoparticle-based biosensors for COVID-19 diagnosis

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative organism of coronavirus disease 2019 (COVID-19) which poses a significant threat to public health worldwide. Though there are certain recommended drugs that can cure COVID-19, their therapeutic efficacy is limited. Therefore, the early and rapid detection without compromising the test accuracy is necessary in order to provide an appropriate treatment for the disease suppression.

Main body

Nanoparticles (NPs) can closely mimic the virus and interact strongly with its proteins due to their morphological similarities. NPs have been widely applied in a variety of medical applications, including biosensing, drug delivery, antimicrobial treatment, and imaging. Recently, NPs-based biosensors have attracted great interest for their biological activities and specific sensing properties, which allows the detection of analytes such as nucleic acids (DNA or RNA), aptamers, and proteins in clinical samples. Further, the advances of nanotechnologies have enabled the development of miniaturized detection systems for point-of-care biosensors, a new strategy for detecting human viral diseases. Among the various NPs, the specific physicochemical properties of gold NPs (AuNPs) are being widely used in the field of clinical diagnostics. As a result, several AuNP-based colorimetric detection methods have been developed.

Short conclusion

The purpose of this review is to provide an overview of the development of AuNPs-based biosensors by virtue of its powerful characteristics as a signal amplifier or enhancer that target pathogenic RNA viruses that provide a reliable and effective strategy for detecting of the existing or newly emerging SARS-CoV-2.

Renal cell carcinoma management: A step to nano-chemoprevention

Renal cell carcinoma (RCC) is one of the most common kidney cancers, responsible for nearly 90 % of all renal malignancies. Despite the availability of many treatment strategies, RCC still remains to be an incurable disease due to its resistivity towards conventional therapies. Nanotechnology is an emerging field of science that offers newer possibilities in therapeutics including cancer medicine, specifically by targeted delivery of anticancer drugs. Several phytochemicals are known for their anti-cancer properties and have been regarded as chemopreventive agents. However, the hydrophobic nature of many phytochemicals decreases its bioavailability and distribution, thus showing limited therapeutic effect. Application of nanotechnology to enhance chemoprevention is an effective strategy to increase the bioavailability of phytochemicals and thereby its therapeutic efficacy. The present review focuses on the utility of nanotechnology in RCC treatment and chemopreventive agents of RCC. We have also visualized the future prospects of nanomolecules in the prevention and cure of RCC.

Nanotherapeutic treatment of the invasive glioblastoma tumor microenvironment

Glioblastoma (GBM) is the most common malignant adult brain cancer with no curative treatment strategy. A significant hurdle in GBM treatment is effective therapeutic delivery to the brain-invading tumor cells that remain following surgery within functioning brain regions. Developing therapies that can either directly target these brain-invading tumor cells or act on other cell types and molecular processes supporting tumor cell invasion and recurrence are essential steps in advancing new treatments in the clinic. This review highlights some of the drug delivery strategies and nanotherapeutic technologies that are designed to target brain-invading GBM cells or non-neoplastic, invasion-supporting cells residing within the GBM tumor microenvironment.

Anti-amyloidogenic property of gold nanoparticle decorated quercetin polymer nanorods in pH and temperature induced aggregation of lysozyme

Quercetin is an abundant plant polyphenol effective against several diseases due to its antioxidant and anti-inflammatory activity. Herein, we report novel polymeric quercetin nanorods and the former decorated with gold nanoparticles for the first time. The prepared conjugates quercetin-polyvinylpyrrolidone (Q-PVP) and quercetin-polyvinylpyrrolidone-gold nanoparticles (Q-PVP-Au) were characterized by UV-visible spectroscopy, Fourier transform infrared, dynamic light scattering, and zeta potential measurements. The surface morphology of conjugates was analyzed by field emission scanning electron microscopy. These conjugates exhibit harmonized rod-like morphology with a narrow size distribution. Furthermore, the quercetin conjugates with nanorod morphology exhibited enhanced and prolonged drug release over a long period. The synthesized conjugates were investigated for lysozyme aggregation kinetics. ThT binding assay, fibril size measurement, and electron microscopy results revealed that conjugates could suppress fibrillogenesis in lysozyme. The highest amyloid aggregation inhibition activity (IC50) was obtained against Q-PVP and Q-PVP-Au at 32 μg mL-1 and 30 μg mL-1 respectively. The amyloid aggregate disintegration activity (DC50) obtained against Q-PVP and Q-PVP-Au was 27 μg mL-1 and 29 μg mL-1 respectively. The present quercetin conjugates exhibit enhanced bioavailability and stability. They were potent inhibitors of lysozyme aggregation that may find applications as a therapeutic agent in neurological diseases like Alzheimer's and Parkinson's.

Bifunctional Calix[4]arene-Coated Gold Nanoparticles for Orthogonal Conjugation

Gold nanoparticles (AuNPs) are currently intensively exploited in the biomedical field as they possess interesting chemical and optical properties. Although their synthesis is well-known, their controlled surface modification with defined densities of ligands such as peptides, DNA, or antibodies remains challenging and has generally to be optimized case by case. This is particularly true for applications like in vivo drug delivery that require AuNPs with multiple ligands, for example a targeting ligand and a drug in well-defined proportions. In this context, we aimed to develop a calixarene-modification strategy that would allow the controlled orthogonal conjugation of AuNPs, respectively, via amide bond formation and copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). To do this, we synthesized a calix[4]arene-tetradiazonium salt bearing four PEG chains ended by an alkyne group (C1) and, after optimization of its grafting on 20 nm AuNPs, we demonstrated that CuAAC can be used to conjugate an azide containing dye (N₃-cya7.5). It was observed that AuNPs coated with C1 (AuNPs-C1) can be conjugated to approximately 600 N₃-cya7.5 that is much higher than the value obtained for AuNPs decorated with traditional thiolated PEG ligands terminated by an alkyne group. The control over the number of molecules conjugated via CuAAC was even possible by incorporating a non-functional calixarene (C2) into the coating layer. We then combined C1 with a calix[4]arene-tetradiazonium salt bearing four carboxyl groups (C3) that allows conjugation of an amine (NH₂-cya7.5) containing dye. The conjugation potential of these bifunctional AuNPs-C1/C3 was quantified by UV-vis spectroscopy: AuNPs decorated with equal amount of C1 and C3 could be conjugated to approximately 350 NH₂-dyes and 300 N₃-dyes using successively amide bond formation and CuAAC, demonstrating the control over the orthogonal conjugation. Such nanoconstructs could benefit to anyone in the need of a controlled modification of AuNPs with two different molecules via two different chemistries.