Advances in Gold Nanoparticle-Based Combined Cancer Therapy

Review of Advances in Coating and Functionalization of Gold Nanoparticles: From Theory to Biomedical Application

Nanoparticles, especially gold nanoparticles (Au NPs) have gained increasing interest in biomedical applications. Used for disease prevention, diagnosis and therapies, its significant advantages in therapeutic efficacy and safety have been the main target of interest. Its application in immune system prevention, stability in physiological environments and cell membranes, low toxicity and optimal bioperformances are critical to the success of engineered nanomaterials. Its unique optical properties are great attractors. Recently, several physical and chemical methods for coating these NPs have been widely used. Biomolecules such as DNA, RNA, peptides, antibodies, proteins, carbohydrates and biopolymers, among others, have been widely used in coatings of Au NPs for various biomedical applications, thus increasing their biocompatibility while maintaining their biological functions. This review mainly presents a general and representative view of the different types of coatings and Au NP functionalization using various biomolecules, strategies and functionalization mechanisms.

Improving the Efficacy of Common Cancer Treatments via Targeted Therapeutics towards the Tumour and Its Microenvironment

Cancer is defined as the uncontrolled proliferation of heterogeneous cell cultures in the body that develop abnormalities and mutations, leading to their resistance to many forms of treatment. Left untreated, these abnormal cell growths can lead to detrimental and even fatal complications for patients. Radiation therapy is involved in around 50% of cancer treatment workflows; however, it presents significant recurrence rates and normal tissue toxicity, given the inevitable deposition of the dose to the surrounding healthy tissue. Chemotherapy is another treatment modality with excessive normal tissue toxicity that significantly affects patients' quality of life. To improve the therapeutic efficacy of radiotherapy and chemotherapy, multiple conjunctive modalities have been proposed, which include the targeting of components of the tumour microenvironment inhibiting tumour spread and anti-therapeutic pathways, increasing the oxygen content within the tumour to revert the hypoxic nature of the malignancy, improving the local dose deposition with metal nanoparticles, and the restriction of the cell cycle within radiosensitive phases. The tumour microenvironment is largely responsible for inhibiting nanoparticle capture within the tumour itself and improving resistance to various forms of cancer therapy. In this review, we discuss the current literature surrounding the administration of molecular and nanoparticle therapeutics, their pharmacokinetics, and contrasting mechanisms of action. The review aims to demonstrate the advancements in the field of conjugated nanomaterials and radiotherapeutics targeting, inhibiting, or bypassing the tumour microenvironment to promote further research that can improve treatment outcomes and toxicity rates.

Experimental and Theoretical Screening of Core Gold Nanoparticles and Their Binding Mechanism to an Anticancer Drug, 2-Thiouracil

This study demonstrated the capability of two readily available optical spectroscopy tools, namely UV-Vis absorption spectrophotometry and Raman/surface-enhanced Raman spectroscopy, to select in a rapid and noninvasive manner the most homogenous gold nanoparticle (AuNP) models and to identify their chemical binding mechanism to 2-thiouracil (2-TU). 2-TU is an anticancer drug of great promise in the antiproliferative and photothermal therapies of cancer. The citrate-capped AuNPs emerged as the most stable as well as time- and cost-effective AuNP model out of the three widely used colloidal nanocores (citrate-, borohydride-citrate-, and sodium dodecyl sulfate (SDS)-capped AuNPs) that were examined. 2-TU chemically attached to the relatively monodispersed AuNPs via a chemisorption mechanism. The 2-TU-AuNPs complex formed through the covalent bonding of the S atom of 2-TU to the nanosurface in a vertical orientation. The spectroscopic results were then confirmed with the help of density functional theory (DFT) calculations and other physicochemical characterization tools for nanomaterials such as transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential. Overall, the purified 2-TU-AuNPs were found to be spherical, had an average diameter of 25 ± 2 nm, a narrow size distribution (1-30 nm), a sharp localized surface plasmon resonance (LSPR) peak at 525 nm, and a negative surface charge (-14 mV).

The Refined Application and Evolution of Nanotechnology in Enhancing Radiosensitivity During Radiotherapy: Transitioning from Gold Nanoparticles to Multifunctional Nanomaterials

Radiotherapy is a pivotal method for treating malignant tumors, and enhancing the therapeutic gain ratio of radiotherapy through physical techniques is the direction of modern precision radiotherapy. Due to the inherent physical properties of high-energy radiation, enhancing the therapeutic gain ratio of radiotherapy through radiophysical techniques inevitably encounters challenges. The combination of hyperthermia and radiotherapy can enhance the radiosensitivity of tumor cells, reduce their radioresistance, and holds significant clinical utility in radiotherapy. Multifunctional nanomaterials with excellent biocompatibility and safety have garnered widespread attention in tumor hyperthermia research, demonstrating promising potential. Utilizing nanotechnology as a sensitizing carrier in conjunction with radiotherapy, and high atomic number nanomaterials can also serve independently as radiosensitizing carriers. This synergy between tumor hyperthermia and radiotherapy may overcome many challenges currently limiting tumor radiotherapy, offering new opportunities for its further advancement. In recent years, the continuous progress in the synthesis and design of novel nanomaterials will propel the future development of medical imaging and cancer treatment. This article summarizes the radiosensitizing mechanisms and effects based on gold nanotechnology and provides an overview of the advancements of other nanoparticles (such as bismuth-based nanomaterials, magnetic nanomaterials, selenium nanomaterials, etc.) in the process of radiation therapy.

Meta-Analysis of Nanoparticle Distribution in Tumors and Major Organs in Tumor-Bearing Mice

Low tumor delivery efficiency is a critical barrier in cancer nanomedicine. This study reports an updated version of "Nano-Tumor Database", which increases the number of time-dependent concentration data sets for different nanoparticles (NPs) in tumors from the previous version of 376 data sets with 1732 data points from 200 studies to the current version of 534 data sets with 2345 data points from 297 studies published from 2005 to 2021. Additionally, the current database includes 1972 data sets for five major organs (i.e., liver, spleen, lung, heart, and kidney) with a total of 8461 concentration data points. Tumor delivery and organ distribution are calculated using three pharmacokinetic parameters, including delivery efficiency, maximum concentration, and distribution coefficient. The median tumor delivery efficiency is 0.67% injected dose (ID), which is low but is consistent with previous studies. Employing the best regression model for tumor delivery efficiency, we generate hypothetical scenarios with different combinations of NP factors that may lead to a higher delivery efficiency of >3%ID, which requires further experimentation to confirm. In healthy organs, the highest NP accumulation is in the liver (10.69%ID/g), followed by the spleen 6.93%ID/g and the kidney 3.22%ID/g. Our perspective on how to facilitate NP design and clinical translation is presented. This study reports a substantially expanded "Nano-Tumor Database" and several statistical models that may help nanomedicine design in the future.

Multiscale Monte Carlo simulations of gold nanoparticle dose-enhanced radiotherapy II. Cellular dose enhancement within macroscopic tumor models

BACKGROUND

Gold NanoParticle (GNP) dose-enhanced radiation therapy (GNPT) requires consideration of physics across macro- to microscopic length scales, however, this presents computational challenges that have limited previous investigations.

PURPOSE

To develop and apply multiscale Monte Carlo (MC) simulations to assess variations in nucleus and cytoplasm dose enhancement factors (n,cDEFs) over tumor-scale volumes.

METHODS

The intrinsic variation of n,cDEFs (due to fluctuations in local gold concentration and cell/nucleus size variation) are estimated via MC modeling of varied cellular GNP uptake and cell/nucleus sizes. Then, the Heterogeneous MultiScale (HetMS) model is implemented in MC simulations by combining detailed models of populations of cells containing GNPs within simplified macroscopic tissue models to evaluate n,cDEFs. Simulations of tumors with spatially uniform gold concentrations (5, 10, or 20 mgAu /gtissue ) and spatially varying gold concentrations eluted from a point are performed to determine n,cDEFs as a function of distance from the source for 10 to 370 keV photons. All simulations are performed for three different intracellular GNP configurations: GNPs distributed on the surface of the nucleus (perinuclear) and GNPs packed into one or four endosome(s).

RESULTS

Intrinsic variations in n,cDEFs can be substantial, for example, if GNP uptake and cell/nucleus radii are varied by 20%, variations of up to 52% in nDEF and 25% in cDEF are observed compared to the nominal values for uniform cell/nucleus size and GNP concentration. In HetMS models of macroscopic tumors, subunity n,cDEFs (i.e., dose decreases) can occur for low energies and high gold concentrations due to attenuation of primary photons through the gold-filled volumes, for example, n,cDEF<1 is observed 3 mm from a 20 keV source for the four endosome configuration. In HetMS simulations of tumors with spatially uniform gold concentrations, n,cDEFs decrease with depth into the tumor as photons are attenuated, with relative differences between GNP models remaining approximately constant with depth in the tumor. Similar initial n,cDEF decreases with radius are seen in the tumors with spatially varying gold concentrations, but the n,cDEFs for all of the GNP configurations converge to a single value for each energy as gold concentration reaches zero.

CONCLUSIONS

The HetMS framework has been implemented for multiscale MC simulations of GNPT to compute n,cDEFs over tumor-scale volumes, with results demonstrating that cellular doses are highly sensitive to cell/nucleus size, GNP intracellular distribution, gold concentration, and cell position in tumor. This work demonstrates the importance of proper choice of computational model when simulating GNPT scenarios and the need to account for intrinsic variations in n,cDEFs due to variations in cell/nucleus size and gold concentration.

Multiscale Monte Carlo simulations of gold nanoparticle dose-enhanced radiotherapy I: Cellular dose enhancement in microscopic models

BACKGROUND

The introduction of Gold NanoParticles (GNPs) in radiotherapy treatments necessitates considerations such as GNP size, location, and quantity, as well as patient geometry and beam quality. Physics considerations span length scales across many orders of magnitude (nanometer-to-centimeter), presenting challenges that often limit the scope of dosimetric studies to either micro- or macroscopic scales.

PURPOSE

To investigate GNP dose-enhanced radiation Therapy (GNPT) through Monte Carlo (MC) simulations that bridge micro-to-macroscopic scales. The work is presented in two parts, with Part I (this work) investigating accurate and efficient MC modeling at the single cell level to calculate nucleus and cytoplasm Dose Enhancement Factors (n,cDEFs), considering a broad parameter space including GNP concentration, GNP intracellular distribution, cell size, and incident photon energy. Part II then evaluates cell dose enhancement factors across macroscopic (tumor) length scales.

METHODS

Different methods of modeling gold within cells are compared, from a contiguous volume of either pure gold or gold-tissue mixture to discrete GNPs in a hexagonal close-packed lattice. MC simulations with EGSnrc are performed to calculate n,cDEF for a cell with radiusr cell = 7.35 $r_{\rm cell}=7.35$  µm and nucleusr nuc = 5 $r_{\rm nuc} = 5$  µm considering 10 to 370 keV incident photons, gold concentrations from 4 to 24 mgAu /gtissue , and three different GNP configurations within the cell: GNPs distributed around the surface of the nucleus (perinuclear) or GNPs packed into one (or four) endosome(s). Select simulations are extended to cells with different cell (and nucleus) sizes: 5 µm (2, 3, and 4 µm), 7.35 µm (4 and 6 µm), and 10 µm (7, 8, and 9 µm).

RESULTS

n,cDEFs are sensitive to the method of modeling gold in the cell, with differences of up to 17% observed; the hexagonal lattice of GNPs is chosen (as the most realistic model) for all subsequent simulations. Across cell/nucleus radii, source energies, and gold concentrations, both nDEF and cDEF are highest for GNPs in the perinuclear configuration, compared with GNPs in one (or four) endosome(s). Across all simulations of the (rcell , rnuc ) = (7.35, 5) µm cell, nDEFs and cDEFs range from unity to 6.83 and 3.87, respectively. Including different cell sizes, nDEFs and cDEFs as high as 21.5 and 5.5, respectively, are observed. Both nDEF and cDEF are maximized at photon energies above the K- or L-edges of gold by 10 to 20 keV.

CONCLUSIONS

Considering 5000 unique simulation scenarios, this work comprehensively investigates many physics trends on DEFs at the cellular level, including demonstrating that cellular DEFs are sensitive to gold modeling approach, intracellular GNP configuration, cell/nucleus size, gold concentration, and incident source energy. These data should prove especially useful in research as well as treatment planning, allowing one to optimize or estimate DEF using not only GNP uptake, but also account for average tumor cell size, incident photon energy, and intracellular configuration of GNPs. Part II will expand the investigation, taking the Part I cell model and applying it in cm-scale phantoms.

Anticancer Activity of Au/CNT Nanocomposite Fabricated by Nanosecond Pulsed Laser Ablation Method on Colon and Cervical Cancer

Gold nanoparticles (AuNPs) and carbon nanotubes (CNTs) are increasingly being investigated for cancer management due to their physicochemical properties, low toxicity, and biocompatibility. This study used an eco-friendly technique (laser synthesis) to fabricate AuNP and Au/CNT nanocomposites. AuNPs, Au/CNTs, and CNTs were tested as potential cancer nanotherapeutics on colorectal carcinoma cells (HCT-116) and cervical cancer cells (HeLa) using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. In addition, the non-cancer embryonic kidney cells HEK-293 were taken as a control in the study. The cell viability assay demonstrated a significant reduction in cancer cell population post 48 h treatments of AuNPs, and Au/CNTs. The average cell viabilities of AuNPs, Au/CNTs, and CNTs for HCT-116 cells were 50.62%, 65.88%, 93.55%, and for HeLa cells, the cell viabilities were 50.88%, 66.51%, 91.73%. The cell viabilities for HEK-293 were 50.44%, 65.80%, 93.20%. Both AuNPs and Au/CNTs showed higher cell toxicity and cell death compared with CNT nanomaterials. The treatment of AuNPs and Au/CNTs showed strong inhibitory action on HCT-116 and HeLa cells. However, the treatment of CNTs did not significantly decrease HCT-116 and HeLa cells, and there was only a minor decrease. The treatment of AuNPs, and Au/CNTs, on normal HEK-293 cells also showed a significant decrease in cell viability, but the treatment of CNTs did not produce a significant decrease in the HEK-293 cells. This study shows that a simplified synthesis technique like laser synthesis for the preparation of high-purity nanomaterials has good efficacy for possible future cancer therapy with minimal toxicity.

Methodological and Cellular Factors Affecting the Magnitude of Breast Cancer and Normal Cell Radiosensitization Using Gold Nanoparticles

Purpose

Breast cancer (BC) is the most common malignant tumor in women, which most often originates from the epithelial tissue of the breast gland. One of the most recommended kinds of treatment is radiotherapy (RT), but irradiation (IR) can affect not only the cancer tumor but also the healthy tissue around it. Au nanoparticles (AuNPs) were proposed as a radiosensitizing agent for RT which would allow for lower radiation doses, reducing the negative radiation effects on healthy tissues. The main objective of the study is to assess the dependence on the radiosensitivity of BC (MDA-MB-231) and normal mammary gland epithelial cells (MCF12A) to ionizing radiation, caused by functionalized AuNPs under diverse conditions.

Methods

The viability, uptake, reactive oxygen species induction, and mitochondrial membrane potential in cells were analyzed applying a time and concentration-dependent manner. After different incubation times with AuNPs, cells were exposed to 2 Gy. The determination of radiation effect in combination with AuNPs was investigated using the clonogenic assay, p53, and γH2AX level, as well as, Annexin V staining.

Results

Our results highlighted the strong need for assessing the experimental conditions' optimization before the AuNPs will be implemented with IR. Moreover, results indicated that AuNPs did not act universally in cells.

Conclusion

AuNPs could be a promising tool as a radiotherapy sensitizing agent, but it should be specified and deeply investigated under what conditions it will be applied taking into consideration not only AuNPs modifications but also the model and experimental conditions.

Gold nanostructure-mediated delivery of anticancer agents: Biomedical applications, reversing drug resistance, and stimuli-responsive nanocarriers

The application of nanoarchitectures in cancer therapy seems to be beneficial for the delivery of antitumor drugs. In recent years, attempts have been made to reverse drug resistance, one of the factors threatening the lives of cancer patients worldwide. Gold nanoparticles (GNPs) are metal nanostructures with a variety of advantageous properties, such as tunable size and shape, continuous release of chemicals, and simple surface modification. This review focuses on the application of GNPs for the delivery of chemotherapy agents in cancer therapy. Utilizing GNPs results in targeted delivery and increased intracellular accumulation. Besides, GNPs can provide a platform for the co-delivery of anticancer agents and genetic tools with chemotherapeutic compounds to exert a synergistic impact. Furthermore, GNPs can promote oxidative damage and apoptosis by triggering chemosensitivity. Due to their capacity for providing photothermal therapy, GNPs can enhance the cytotoxicity of chemotherapeutic agents against tumor cells. The pH-, redox-, and light-responsive GNPs are beneficial for drug release at the tumor site. For the selective targeting of cancer cells, surface modification of GNPs with ligands has been performed. In addition to improving cytotoxicity, GNPs can prevent the development of drug resistance in tumor cells by facilitating prolonged release and loading low concentrations of chemotherapeutics while maintaining their high antitumor activity. As described in this study, the clinical use of chemotherapeutic drug-loaded GNPs is contingent on enhancing their biocompatibility.

Insights into Gold Nanoparticles Possibilities for Diagnosis and Treatment of the Head and Neck Upper Aerodigestive Tract Cancers

Background: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer affecting people and accounts for more than 300,000 deaths worldwide. Improvements in treatment modalities, including immunotherapy, have demonstrated promising prognoses for eligible patients. Nevertheless, the five-year overall survival rate has not increased significantly, and the tumor recurrence ratio remains at 50% or higher, except for patients with HPV-positive HNSCC. Over the last decades, nanotechnology has provided promising tools, especially for biomedical applications, due to some remarkable physicochemical properties of numerous nanomaterials, particularly gold nanoparticles. This review addresses the features and some applications of gold nanoparticles reported in the literature over the last five years regarding the diagnosis and treatment of head and neck cancer, highlighting the exciting possibilities of this nanomaterial in oncology. Methods: The scientific papers selected for this review were obtained from the PubMed Advanced, Web of Science, Scopus, ClinicalTrials.gov, and Google Scholar platforms. Conclusions: Results from papers applying gold nanoparticles have suggested that their application is a feasible approach to diagnostics, prognostics, and the treatment of HNC. Moreover, phase I clinical trials suggest that gold nanoparticles are safe and can potentially become theranostic agents for humans.

Mechanisms of Nanoscale Radiation Enhancement by Metal Nanoparticles: Role of Low Energy Electrons

Metal nanoparticles are considered as highly promising radiosensitizers in cancer radiotherapy. Understanding their radiosensitization mechanisms is critical for future clinical applications. This review is focused on the initial energy deposition by short-range Auger electrons; when high energy radiation is absorbed by gold nanoparticles (GNPs) located near vital biomolecules; such as DNA. Auger electrons and the subsequent production of secondary low energy electrons (LEEs) are responsible for most the ensuing chemical damage near such molecules. We highlight recent progress on DNA damage induced by the LEEs produced abundantly within about 100 nanometers from irradiated GNPs; and by those emitted by high energy electrons and X-rays incident on metal surfaces under differing atmospheric environments. LEEs strongly react within cells; mainly via bound breaking processes due to transient anion formation and dissociative electron attachment. The enhancement of damages induced in plasmid DNA by LEEs; with or without the binding of chemotherapeutic drugs; are explained by the fundamental mechanisms of LEE interactions with simple molecules and specific sites on nucleotides. We address the major challenge of metal nanoparticle and GNP radiosensitization; i.e., to deliver the maximum local dose of radiation to the most sensitive target of cancer cells (i.e., DNA). To achieve this goal the emitted electrons from the absorbed high energy radiation must be short range, and produce a large local density of LEEs, and the initial radiation must have the highest possible absorption coefficient compared to that of soft tissue (e.g., 20-80 keV X-rays).

Targeted Lymphoma Therapy Using a Gold Nanoframework-Based Drug Delivery System

Precision nanomedicine can be employed as an alternative to chemo- or radiotherapy to overcome challenges associated with the often narrow therapeutic window of traditional treatment approaches, while safely inducing effective, targeted antitumor responses. Herein, we report the formulation of a therapeutic nanocomposite comprising a hyaluronic acid (HA)-coated gold nanoframework (AuNF) delivery system and encapsulated IT848, a small molecule with potent antilymphoma and -myeloma properties that targets the transcriptional activity of nuclear factor kappa B (NF-κB). The porous AuNFs fabricated via a liposome-templated approach were loaded with IT848 and surface-functionalized with HA to formulate the nanotherapeutics that were able to efficiently deliver the payload with high specificity to myeloma and lymphoma cell lines in vitro. In vivo studies characterized biodistribution, pharmacokinetics, and safety of HA-AuNFs, and we demonstrated superior efficacy of HA-AuNF-formulated IT848 vs free IT848 in lymphoma mouse models. Both in vitro and in vivo results affirm that the AuNF system can be adopted for targeted cancer therapy, improving the drug safety profile, and enhancing its efficacy with minimal dosing. HA-AuNF-formulated IT848 therefore has strong potential for clinical translation.

Biogenic Selenium Nanoparticles in Biomedical Sciences: Properties, Current Trends, Novel Opportunities and Emerging Challenges in Theranostic Nanomedicine

Selenium is an important dietary supplement and an essential trace element incorporated into selenoproteins with growth-modulating properties and cytotoxic mechanisms of action. However, different compounds of selenium usually possess a narrow nutritional or therapeutic window with a low degree of absorption and delicate safety margins, depending on the dose and the chemical form in which they are provided to the organism. Hence, selenium nanoparticles (SeNPs) are emerging as a novel therapeutic and diagnostic platform with decreased toxicity and the capacity to enhance the biological properties of Se-based compounds. Consistent with the exciting possibilities offered by nanotechnology in the diagnosis, treatment, and prevention of diseases, SeNPs are useful tools in current biomedical research with exceptional benefits as potential therapeutics, with enhanced bioavailability, improved targeting, and effectiveness against oxidative stress and inflammation-mediated disorders. In view of the need for developing eco-friendly, inexpensive, simple, and high-throughput biomedical agents that can also ally with theranostic purposes and exhibit negligible side effects, biogenic SeNPs are receiving special attention. The present manuscript aims to be a reference in its kind by providing the readership with a thorough and comprehensive review that emphasizes the current, yet expanding, possibilities offered by biogenic SeNPs in the biomedical field and the promise they hold among selenium-derived products to, eventually, elicit future developments. First, the present review recalls the physiological importance of selenium as an oligo-element and introduces the unique biological, physicochemical, optoelectronic, and catalytic properties of Se nanomaterials. Then, it addresses the significance of nanosizing on pharmacological activity (pharmacokinetics and pharmacodynamics) and cellular interactions of SeNPs. Importantly, it discusses in detail the role of biosynthesized SeNPs as innovative theranostic agents for personalized nanomedicine-based therapies. Finally, this review explores the role of biogenic SeNPs in the ongoing context of the SARS-CoV-2 pandemic and presents key prospects in translational nanomedicine.

A Review on the Use of Gold Nanoparticles in Cancer Treatment

According to a 2020 WHO study, cancer is responsible for one in every six fatalities. One in four patients die due to side effects and intolerance to chemotherapy, making it a leading cause of patient death. Compared to traditional tumor therapy, emerging treatment methods, including immunotherapy, gene therapy, photothermal therapy, and photodynamic therapy, have proven to be more effective. The aim of this review is to highlight the role of gold nanoparticles in advanced cancer treatment. A systematic and extensive literature review was conducted using the Web of Science, PubMed, EMBASE, Google Scholar, NCBI, and various websites. Highly relevant literature from 141 references was chosen for inclusion in this review. Recently, the synergistic benefits of nano therapy and cancer immunotherapy have been shown, which could allow earlier diagnosis, more focused cancer treatment, and improved disease control. Compared to other nanoparticles, the physical and optical characteristics of gold nanoparticles appear to have significantly greater effects on the target. It has a crucial role in acting as a drug carrier, biomarker, anti-angiogenesis agent, diagnostic agent, radiosensitizer, cancer immunotherapy, photodynamic therapy, and photothermal therapy. Gold nanoparticle-based cancer treatments can greatly reduce current drug and chemotherapy dosages.

Gold Nanoparticles Synthesized by an Aqueous Extract of Codium tomentosum as Potential Antitumoral Enhancers of Gemcitabine

Cancer still poses a global threat, since a lot of tumors remain untreatable despite all the available chemotherapeutic drugs, whose side effects, it must also be noted, still raise concerns. The antitumoral properties of marine seaweeds make them a potential source of new, less toxic, and more active antitumoral agents. Furthermore, these natural extracts can be combined with nanotechnology to increase their efficacy and improve targeting. In this work, a Codium tomentosum (CT) aqueous extract was employed for the green synthesis of gold nanoparticles (Au@CT). The complete characterization of Au@CT was performed by UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Zeta potential, electron microscopy, X-ray powder diffraction (XRD), high-performance steric exclusion chromatography (HPSEC), and by the determination of their antioxidant capacity. The antiproliferative activity of Au@CT was then tested in hepatic (HEPG-2) and pancreatic (BxPC-3) cell lines. Their potential capacity as enhancers of gemcitabine, a drug frequently used to treat both types of tumors, was also tested. The activity of Au@CT was compared to the activity of the CT extract alone. A synergistic effect with gemcitabine was proven for HEPG-2. Our results showed that gold nanoparticles synthesized from seaweed extracts with antitumoral activity could be a good gemcitabine enhancer.

Biomedical Applications of Biosynthesized Gold Nanoparticles from Cyanobacteria: an Overview

Recently there had been a great interest in biologically synthesized nanoparticles (NPs) as potential therapeutic agents. The shortcomings of conventional non-biological synthesis methods such as generation of toxic byproducts, energy consumptions, and involved cost have shifted the attention towards green syntheses of NPs. Among noble metal NPs, gold nanoparticles (AuNPs) are the most extensively used ones, owing to the unique physicochemical properties. AuNPs have potential therapeutic applications, as those are synthesized with biomolecules as reducing and stabilizing agent(s). The green method of AuNP synthesis is simple, eco-friendly, non-toxic, and cost-effective with the use of renewable energy sources. Among all taxa, cyanobacteria have attracted considerable attention as nano-biofactories, due to cellular uptake of heavy metals from the environment. The cellular bioactive pigments, enzymes, and polysaccharides acted as reducing and coating agents during the process of biosynthesis. However, cyanobacteria-mediated AuNPs have potential biomedical applications, namely, targeted drug delivery, cancer treatment, gene therapy, antimicrobial agent, biosensors, and imaging.

Biological Response of Human Cancer Cells to Ionizing Radiation in Combination with Gold Nanoparticles

Simple Summary

Various types of metallic nanoparticles and especially gold nanoparticles (AuNPs) have been utilized in radiation studies to enhance the radiosensitization of cancer cells while minimizing detrimental effects in normal tissue. The aim of our study was to investigate the biological responses of various human cancer cells to gold-nanoparticle-induced radiosensitization. This was accomplished by using different AuNPs and several techniques in order to provide valuable insights regarding the multiple adverse biological effects, following ionizing radiation (IR) in combination with AuNPs. Insightful methodologies such as transmission electron microscopy were employed to identify comprehensively the complexity of the biological damage occurrence. Our findings confirm that AuNP radiosensitization may occur due to extensive and/or complex DNA damage, cell death, or cellular senescence. This multiparameter study aims to further elucidate the biological mechanisms and at the same time provide new information regarding the use of AuNPs as radiosensitizers in cancer treatment.

Abstract

In the context of improving radiation therapy, high-atomic number (Z) metallic nanoparticles and, more importantly, gold-based nanostructures are developed as radiation enhancers/radiosensitizers. Due to the diversity of cell lines, nanoparticles, as well as radiation types or doses, the resulting biological effects may differ and remain obscure. In this multiparameter study, we aim to shed light on these effects and investigate them further by employing X-irradiation and three human cancer cell lines (PC3, A549, and U2OS cells) treated by multiple techniques. TEM experiments on PC3 cells showed that citrate-capped AuNPs were found to be located mostly in membranous structures/vesicles or autophagosomes, but also, in the case of PEG-capped AuNPs, inside the nucleus as well. The colony-forming capability of cancer cells radiosensitized by AuNPs decreased significantly and the DNA damage detected by cytogenetics, γH2AX immunostaining, and by single (γH2AX) or double (γH2AX and OGG1) immunolocalization via transmission electron microscopy (TEM) was in many cases higher and/or persistent after combination with AuNPs than upon individual exposure to ionizing radiation (IR). Moreover, different cell cycle distribution was evident in PC3 but not A549 cells after treatment with AuNPs and/or irradiation. Finally, cellular senescence was investigated by using a newly established staining procedure for lipofuscin, based on a Sudan Black-B analogue (GL13) which showed that based on the AuNPs’ concentration, an increased number of senescent cells might be observed after exposure to IR. Even though different cell lines or different types and concentrations of AuNPs may alter the levels of radiosensitization, our results imply that the complexity of damage might also be an important factor of AuNP-induced radiosensitization.

Enhancing nanoparticle accumulation in two dimensional, three dimensional, and xenograft mouse cancer cell models in the presence of docetaxel

Recent clinical trials show docetaxel (DTX), given in conjunction with radiation therapy (RT) and androgen suppression, improves survival in high-risk prostate cancer. Addition of gold nanoparticles (GNPs) to this current DTX/RT protocol is expected to further improve therapeutic benefits remarkably. However, the foundation for the triple combination of RT, DTX, and GNPs must be elucidated to ensure quicker facilitation to the clinic. In this study, we explored the use of low concentrations of DTX combined with GNPs in two prostate cancer cell lines in a two-dimensional monolayer, a three-dimensional spheroid, and a mouse xenograft model. When used together, DTX and GNPs induced a nearly identical relative increase in uptake of gold in both the spheroid model and the mouse xenograft, which saw a 130% and 126% increase respectively after 24 h, showcasing the benefit of using spheroids as an in vitro model to better optimize in vivo experiments. Further, the benefits of using low concentrations of DTX combined with GNPs extended for over 72 h, allowing for less frequency in dosing when translating to the clinic. Overall, these results highlight the benefits of using DTX combined with GNPs and lays the groundwork for the translation of the triple combination of RT, GNPs, and DTX to the clinic.

Synthesis and Characterization of the Nanogold-Bound Ternary Copper(II) Complex of Phenanthroline and Cysteine as Potential Anticancer Agents

The aim of this study was to synthesize and characterize a nanogold-{[(Cu)(phen)(cys)(H₂O)]NO₃}_n conjugate and to evaluate its antiproliferative property against the breast cancer cell line (MCF7) and normal cell line (MCF10A). Nanogold solution was prepared using the Turkevich method. In one approach, a ternary copper(II) complex of 1,10-phenanthroline with l-cysteine, [(Cu)(phen)(cys)(H₂O)]NO₃, was first prepared and then tethered with the gold nanoparticles. In another approach, gold nanoparticles were reacted with l-cysteine, copper(II) nitrate, and 1,10-phenanthroline subsequently. The synthesized [(Cu)(phen)(cys)(H₂O)]NO₃ complex was characterized by Fourier transform infrared (FTIR) and electrospray ionization mass spectrometry techniques, which showed that l-cysteine was bound to the copper through carboxylic and amino groups, with the thiol moiety remaining free. The free thiol group was bound to the nanogold surface to form the nanogold-{[(Cu)(phen)(cys)(H₂O)]NO₃}_n conjugate, as evidenced by the increase in the surface plasmon absorption band in ultraviolet-visible and the absence of a thiol peak in FTIR of the nanogold-copper complex conjugate. The anticancer activity of the nanogold-copper complex conjugate and the free copper complex against a breast cancer cell line (MCF7) and their toxicity on a normal cell line (MCF10A) were examined using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy phenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Results suggested that the nanogold-{[(Cu)(phen)(cys)(H₂O)]NO₃}_n conjugate demonstrates a selective antiproliferative and proapoptotic effect on the breast cancer cells, confirming the potential of the nanogold-copper complex conjugate as an anticancer agent.

Gold Nanoparticle-Based Therapy for Muscle Inflammation and Oxidative Stress

Proinflammatory cytokines and reactive oxygen species are released after muscle damage, and although they are necessary for the muscle regeneration process, an excess of these substances leads to the destruction of biomolecules and impairment of the repair system. Several drugs have emerged in recent years to control the muscle inflammatory response, and studies have shown that gold nanoparticles (AuNPs) have anti-inflammatory and antioxidant properties. This review reveals the effects of AuNPs on the inflammatory and redox mechanisms of muscles. We assessed the results of several studies published in different journals over the last 20 years, with a focus on the effects of AuNPs on possible aspects of muscle regeneration or recovery, namely, inflammatory processes and redox system mechanisms. A systematic database search was conducted using PubMed, Medline, Bireme, Web of Science, and Google Scholar to identify peer-reviewed studies from the 2000s. Combinations of keywords related to muscle damage, regeneration or repair, AuNPs, oxidative stress, and antioxidants were used in the search. This review did not address other variables, such as specific diseases or other biological effects; however, these variables should be considered for a complete understanding of the effects of AuNPs on skeletal muscles.

Engineering Gold Nanostructures for Cancer Treatment: Spherical Nanoparticles, Nanorods, and Atomically Precise Nanoclusters

Cancer is a major global health issue and is a leading cause of mortality. It has been documented that various conventional treatments can be enhanced by incorporation with nanomaterials. Thanks to their rich optical properties, excellent biocompatibility, and tunable chemical reactivities, gold nanostructures have been gaining more and more research attention for cancer treatment in recent decades. In this review, we first summarize the recent progress in employing three typical gold nanostructures, namely spherical Au nanoparticles, Au nanorods, and atomically precise Au nanoclusters, for cancer diagnostics and therapeutics. Following that, the challenges and the future perspectives of this field are discussed. Finally, a brief conclusion is summarized at the end.

Nanoengineered Sprayable Therapy for Treating Myocardial Infarction

We report the development, as well as the in vitro and in vivo testing, of a sprayable nanotherapeutic that uses surface engineered custom-designed multiarmed peptide grafted nanogold for on-the-spot coating of an infarcted myocardial surface. When applied to mouse hearts, 1 week after infarction, the spray-on treatment resulted in an increase in cardiac function (2.4-fold), muscle contractility, and myocardial electrical conductivity. The applied nanogold remained at the treatment site 28 days postapplication with no off-target organ infiltration. Further, the infarct size in the mice that received treatment was found to be <10% of the total left ventricle area, while the number of blood vessels, prohealing macrophages, and cardiomyocytes increased to levels comparable to that of a healthy animal. Our cumulative data suggest that the therapeutic action of our spray-on nanotherapeutic is highly effective, and in practice, its application is simpler than other regenerative approaches for treating an infarcted heart.

Photothermal and Photodynamic Therapy of Tumors with Plasmonic Nanoparticles: Challenges and Prospects

Cancer remains one of the leading causes of death in the world. For a number of neoplasms, the efficiency of conventional chemo- and radiation therapies is insufficient because of drug resistance and marked toxicity. Plasmonic photothermal therapy (PPT) using local hyperthermia induced by gold nanoparticles (AuNPs) has recently been extensively explored in tumor treatment. However, despite attractive promises, the current PPT status is limited by laboratory experiments, academic papers, and only a few preclinical studies. Unfortunately, most nanoformulations still share a similar fate: great laboratory promises and fair preclinical trials. This review discusses the current challenges and prospects of plasmonic nanomedicine based on PPT and photodynamic therapy (PDT). We start with consideration of the fundamental principles underlying plasmonic properties of AuNPs to tune their plasmon resonance for the desired NIR-I, NIR-2, and SWIR optical windows. The basic principles for simulation of optical cross-sections and plasmonic heating under CW and pulsed irradiation are discussed. Then, we consider the state-of-the-art methods for wet chemical synthesis of the most popular PPPT AuNPs such as silica/gold nanoshells, Au nanostars, nanorods, and nanocages. The photothermal efficiencies of these nanoparticles are compared, and their applications to current nanomedicine are shortly discussed. In a separate section, we discuss the fabrication of gold and other nanoparticles by the pulsed laser ablation in liquid method. The second part of the review is devoted to our recent experimental results on laser-activated interaction of AuNPs with tumor and healthy tissues and current achievements of other research groups in this application area. The unresolved issues of PPT are the significant accumulation of AuNPs in the organs of the mononuclear phagocyte system, causing potential toxic effects of nanoparticles, and the possibility of tumor recurrence due to the presence of survived tumor cells. The prospective ways of solving these problems are discussed, including developing combined antitumor therapy based on combined PPT and PDT. In the conclusion section, we summarize the most urgent needs of current PPT-based nanomedicine.

Comprehensive comparison of theranostic nanoparticles in breast cancer

Breast cancer is the most frequently happening cancer and the most typical cancer death among females. Despite the crucial progress in breast cancer therapy by using Chemotherapeutic agents, most anti-tumor drugs are insufficient to destroy exactly the breast cancer cells. The noble method of drug delivery using nanoparticles presents a great promise in treating breast cancer most sufficiently and with the least harm to the patient. Nanoparticles, with their spectacular characteristics, help overcome problems of this kind. Unique features of nanoparticles such as biocompatibility, bioavailability, biodegradability, sustained release, and, most importantly, site-specific targeting enables the Chemotherapeutic agents loaded in nanocarriers to differentiate between healthy tissue and cancer cells, leading to low toxicity and fewer side effects. This review focuses on evaluating and comprehending nanoparticles utilized in breast cancer treatment, including the most recent data related to the drugs they can carry. Also, this review covers all information related to each nanocarrier, such as their significant characteristics, subtypes, advantages, disadvantages, and chemical modification methods with recently published studies. This article discusses over 21 nanoparticles used in breast cancer treatment with possible chemical ligands such as monoclonal antibodies and chemotherapeutic agents binding to these carriers. These different nanoparticles and the unique features of each nanocarrier give the researchers all the data and insight to develop and use the brand-new drug delivery system.

Nanotechnology Driven Cancer Chemoradiation: Exploiting the Full Potential of Radiotherapy with a Unique Combination of Gold Nanoparticles and Bleomycin

One of the major issues in current radiotherapy (RT) is the associated normal tissue toxicity. Enhancement of the RT effect with novel radiosensitizers can address this need. In this study, gold nanoparticles (GNPs) and bleomycin (BLM) were used as a unique combination of radiosensitizers. GNPs offer a two-fold promise as a delivery vehicle for BLM and as a radiosensitizing agent. In this study, GNPs were functionalized and complexed with BLM using a gold-thiol bond (denoted GNP-BLM). Our results show that there was a 40% and 10% decrease in cell growth with GNP-BLM vs. free BLM for the MIA PaCa-2 and PC-3 cell lines, respectively. Testing the GNP-BLM platform with RT showed an 84% and 13% reduction in cell growth in MIA PaCa-2 cells treated with GNP-BLM and GNPs, respectively. Similar results were seen with PC-3 cells. The efficacy of this approach was verified by mapping DNA double-strand breaks (DSBs) as well. Therefore, this proposed incorporation of nanomedicine with RT is promising in achieving a significantly higher therapeutic ratio which is necessary to make a paradigm change to the current clinical approach.

Multifunctional inorganic nanomaterials for cancer photoimmunotherapy

Phototherapy and immunotherapy in combination is regarded as the ideal therapeutic modality to treat both primary and metastatic tumors. Immunotherapy uses different immunological approaches to stimulate the immune system to identify tumor cells for targeted elimination. Phototherapy destroys the primary tumors by light irradiation, which induces a series of immune responses through triggering immunogenic cancer cell death. Therefore, when integrating immunotherapy with phototherapy, a novel anti-cancer strategy called photoimmunotherapy (PIT) is emerging. This synergistic treatment modality can not only enhance the effectiveness of both therapies but also overcome their inherent limitations, opening a new era for the current anti-cancer therapy. Recently, the advancement of nanomaterials affords a platform for PIT. From all these nanomaterials, inorganic nanomaterials stand out as ideal mediators in PIT due to their unique physiochemical properties. Inorganic nanomaterials can not only serve as carriers to transport immunomodulatory agents in immunotherapy owing to their excellent drug-loading capacity but also function as photothermal agents or photosensitizers in phototherapy because of their great optical characteristics. In this review, the recent advances of multifunctional inorganic nanomaterial-mediated drug delivery and their contributions to cancer PIT will be highlighted.

Potential toxicity of nanoparticles on the reproductive system animal models: A review

Over the past two decades, nanotechnology has been involved in an array of applications in various fields, including diagnostic kits, disease treatment, drug manufacturing, drug delivery, and gene therapy. But concerns about the toxicity of nanoparticles have greatly hindered their use; also, due to their increasing use in various industries, all members of society are exposed to the toxicity of these nanoparticles. Nanoparticles have a negative impact on various organs, including the reproductive system. They also can induce abortion in women, reduce fetal growth and development, and can damage the reproductive system and sperm morphology in men. In some cases, it has been observed that despite the modification of nanoparticles in composition, concentration, and method of administration, there is still damage to the reproductive organs. Therefore, understanding how nanoparticles affect the reproductive system is of very importance. In several studies, the nanoparticle toxicity effect on the genital organs has been investigated at the clinical and molecular levels using the in vivo and in vitro models. This study reviews these investigations and provides important data on the toxicity, hazards, and safety of nanoparticles in the reproductive system to facilitate the optimal use of nanoparticles in the industry.

Radiosensitization Effect of Gold Nanoparticles in Proton Therapy

The number of proton therapy facilities and the clinical usage of high energy proton beams for cancer treatment has substantially increased over the last decade. This is mainly due to the superior dose distribution of proton beams resulting in a reduction of side effects and a lower integral dose compared to conventional X-ray radiotherapy. More recently, the usage of metallic nanoparticles as radiosensitizers to enhance radiotherapy is receiving growing attention. While this strategy was originally intended for X-ray radiotherapy, there is currently a small number of experimental studies indicating promising results for proton therapy. However, most of these studies used low proton energies, which are less applicable to clinical practice; and very small gold nanoparticles (AuNPs). Therefore, this proof of principle study evaluates the radiosensitization effect of larger AuNPs in combination with a 200 MeV proton beam. CHO-K1 cells were exposed to a concentration of 10 μg/ml of 50 nm AuNPs for 4 hours before irradiation with a clinical proton beam at NRF iThemba LABS. AuNP internalization was confirmed by inductively coupled mass spectrometry and transmission electron microscopy, showing a random distribution of AuNPs throughout the cytoplasm of the cells and even some close localization to the nuclear membrane. The combined exposure to AuNPs and protons resulted in an increase in cell killing, which was 27.1% at 2 Gy and 43.8% at 6 Gy, compared to proton irradiation alone, illustrating the radiosensitizing potential of AuNPs. Additionally, cells were irradiated at different positions along the proton depth-dose curve to investigate the LET-dependence of AuNP radiosensitization. An increase in cytogenetic damage was observed at all depths for the combined treatment compared to protons alone, but no incremental increase with LET could be determined. In conclusion, this study confirms the potential of 50 nm AuNPs to increase the therapeutic efficacy of proton therapy.

Gold Nanoparticles Modified With Polyethyleneimine Disturbed the Activity of Drug-Metabolic Enzymes and Induced Inflammation-Mediated Liver Injury in Mice

Gold nanoparticles (GNPs) have been used as a potential bioactive platform for drug delivery due to their unique optical and thermal characteristics. Liver is the main organ in orchestrating physiological homeostasis through metabolization of drugs and detoxification of exogenous substances. Therefore, it is crucial to deeply understand the mechanism of nanoparticle–liver interaction and the potential hepatic effects of GNPs in vivo. In this study, we studied the hepatic impacts of the intravenously injected polyethyleneimine (PEI)-modified GNPs (PEI-GNPs) on the expression of hepatic drug-metabolic enzymes and sterol responsive element binding protein 1c (SREBP-1c)-mediated de novo lipogenesis in mice for 24 h and 1 week. PEI-GNP accumulation in the liver is associated with increased liver inflammation, as evidenced by the gene expression of pro-inflammatory cytokines. Moreover, the GNP-induced hepatotoxicity in mice is partly due to liver inflammation–triggered disruption in the function of drug-metabolic enzymes, including hepatic uptake and efflux transporters, cytochrome P450 (CYP450), and UDP-glucuronosyltransferases (UGTs). The study provides evidence that it is necessary to consider the nanomaterial–liver interaction and manipulate the surface chemistry of GNPs prior to biomedical application of nanoparticles.

Revisiting inorganic nanoparticles as promising therapeutic agents: A paradigm shift in oncological theranostics

Cancer remains a global health problem largely due to a lack of effective therapies. Major cancer management strategies include chemotherapy, surgical resection, and radiation. Unfortunately, these strategies have a number of limitations, such as non-specific side effects, uneven delivery of the drugs, and lack of proper monitoring technology. Inorganic nanoparticles (NPs) are considered promising agents in treating and tracing cancer due to their unique physicochemical properties such as the controlled release of drugs, bioavailability, biocompatibility, stability, and large surface area. Also, they enhance the solubility of hydrophobic drugs, prolong their circulation time, prevent undesired off-targeting and subsequent side effects, making them efficient particles in cancer theranostics. Promising inorganic-NPs include gold, selenium, silica, and oxide NPs. Further, several techniques are used to modify the surface of inorganic-NPs, making them more efficient for the effective transport of therapeutic cargos to overcome cellular barriers. Thus, inorganic-NPs function effectively, surmounting the intrinsic drawbacks of traditional organic NPs. This mini-review summarizes the significant inorganic-NPs, their properties, surface modifications, cellular uptake, and bio-distributions, along with their potential use in cancer theranostics. We also discuss the promises and challenges faced during the inorganic-NPs mediated therapeutic approach for cancer and these particles' status in the clinical setting.

Investigation of Nano-Bio Interactions within a Pancreatic Tumor Microenvironment for the Advancement of Nanomedicine in Cancer Treatment

Pancreatic cancer is one of the deadliest types of cancer, with a five-year survival rate of only 10%. Nanotechnology offers a novel perspective to treat such deadly cancers through their incorporation into radiotherapy and chemotherapy. However, the interaction of nanoparticles (NPs) with cancer cells and with other major cell types within the pancreatic tumor microenvironment (TME) is yet to be understood. Therefore, our goal is to shed light on the dynamics of NPs within a TME of pancreatic origin. In addition to cancer cells, normal fibroblasts (NFs) and cancer-associated fibroblasts (CAFs) were examined in this study due to their important yet opposite roles of suppressing tumor growth and promoting tumor growth, respectively. Gold nanoparticles were used as the model NP system due to their biocompatibility and physical and chemical proprieties, and their dynamics were studied both quantitatively and qualitatively in vitro and in vivo. The in vitro studies revealed that both cancer cells and CAFs take up 50% more NPs compared to NFs. Most importantly, they all managed to retain 70–80% of NPs over a 24-h time period. Uptake and retention of NPs within an in vivo environment was also consistent with in vitro results. This study shows the paradigm-changing potential of NPs to combat the disease.

Gold Nanomaterials as a Promising Integrated Tool for Diagnosis and Treatment of Pathogenic Infections-A Review

This review summarizes research on functionalized gold nanomaterials as pathogen detection sensors and pathogen elimination integrated tools. After presenting the challenge of current severe threat from pathogenic bacteria and the increasingly serious growth rate of drug resistance, the first section mainly introduces the conspectus of gold nanostructures from synthesis, characterization, physicochemical properties and applications of gold nanomaterials. The next section deals with gold nanomaterials-based pathogen detection sensors such as colorimetric sensors, fluorescence sensors and Surface-Enhanced Raman Scattering sensors. We then discuss strategies based on gold nanomaterials for eliminating pathogenic infections, such as the dual sterilization strategy for grafting gold nanomaterials with antibacterial substances, photothermal antibacterial and photodynamic antibacterial methods. The fourth part briefly introduces the comprehensive strategy for diagnosis and sterilization of pathogen infection based on gold nanomaterials, such as the diagnosis and treatment strategy for pathogen infection using Roman signals real-time monitoring and photothermal sterilization. A concluding section that summarizes the current status and challenges of the novel diagnosis and treatment integrated strategy for pathogenic infections, gives an outlook on potential future perspectives.

Multi-Functionalized Nanomaterials and Nanoparticles for Diagnosis and Treatment of Retinoblastoma

Retinoblastoma is a rare type of cancer, and its treatment, as well as diagnosis, is challenging, owing to mutations in the tumor-suppressor genes and lack of targeted, efficient, cost-effective therapy, exhibiting a significant need for novel approaches to address these concerns. For this purpose, nanotechnology has revolutionized the field of medicine with versatile potential capabilities for both the diagnosis, as well as the treatment, of retinoblastoma via the targeted and controlled delivery of anticancer drugs via binding to the overexpressed retinoblastoma gene. Nanotechnology has also generated massive advancements in the treatment of retinoblastoma based on the use of surface-tailored multi-functionalized nanocarriers; overexpressed receptor-based nanocarriers ligands (folate, galactose, and hyaluronic acid); lipid-based nanocarriers; and metallic nanocarriers. These nanocarriers seem to benchmark in mitigating a plethora of malignant retinoblastoma via targeted delivery at a specified site, resulting in programmed apoptosis in cancer cells. The effectiveness of these nanoplatforms in diagnosing and treating intraocular cancers such as retinoblastoma has not been properly discussed, despite the increasing significance of nanomedicine in cancer management. This article reviewed the recent milestones and future development areas in the field of intraocular drug delivery and diagnostic platforms focused on nanotechnology.

Three-Dimensional Tumor Spheroids as a Tool for Reliable Investigation of Combined Gold Nanoparticle and Docetaxel Treatment

Simple Summary

Due to the normal tissue toxicity induced by standard therapeutic options such as radiotherapy and chemotherapy, alternative solutions are being explored. Nanomaterials, such as gold nanoparticles, can help reduce side effects by increasing targeted dose to the tumor as well as act as a drug delivery system. Many nano-based systems are tested in a two-dimensional monolayer in the lab, which is not representative of the complex tumor microenvironment. Towards an accelerated translation to the clinic, use of nanomaterials, like the radio-sensitizing gold nanoparticles, were tested in three-dimensional spheroids, which exhibit many properties present in a real tumor such as the extracellular matrix, necrotic cores, and nutrient gradients. This work paves the way for more accurate experimentation in the lab that is more indicative of a real tumor response, leading to a higher chance of success in future clinical studies and clinical treatment.

Abstract

Radiotherapy and chemotherapy are the gold standard for treating patients with cancer in the clinic but, despite modern advances, are limited by normal tissue toxicity. The use of nanomaterials, such as gold nanoparticles (GNPs), to improve radiosensitivity and act as drug delivery systems can mitigate toxicity while increasing deposited tumor dose. To expedite a quicker clinical translation, three-dimensional (3D) tumor spheroid models that can better approximate the tumor environment compared to a two-dimensional (2D) monolayer model have been used. We tested the uptake of 15 nm GNPs and 50 nm GNPs on a monolayer and on spheroids of two cancer cell lines, CAL-27 and HeLa, to evaluate the differences between a 2D and 3D model in similar conditions. The anticancer drug docetaxel (DTX) which can act as a radiosensitizer, was also utilized, informing future potential of GNP-mediated combined therapeutics. In the 2D monolayer model, the addition of DTX induced a small, non-significant increase of uptake of GNPs of between 13% and 24%, while in the 3D spheroid model, DTX increased uptake by between 47% and 186%, with CAL-27 having a much larger increase relative to HeLa. Further, the depth of penetration of 15 nm GNPs over 50 nm GNPs increased by 33% for CAL-27 spheroids and 17% for HeLa spheroids. These results highlight the necessity to optimize GNP treatment conditions in a more realistic tumor-life environment. A 3D spheroid model can capture important details, such as different packing densities from different cancer cell lines, which are absent from a simple 2D monolayer model.

Colloidal Stability and Cytotoxicity of Polydopamine-Conjugated Gold Nanorods against Prostate Cancer Cell Lines

Prostate cancer is one of the most common cancers in men. Cell invasion is an important step in the process of cancer metastasis. Herein, gold nanorods (GNRs) and polyethylene glycol (PEG)-coated GNRs were conjugated with polydopamine (PDA). The PDA-nanoconjugates demonstrated excellent colloidal stability upon lyophilization and dispersion in cell culture media with or without the addition of fetal bovine albumin (FBS), compared to unconjugated GNRs. PDA-nanoconjugates exhibited a considerable cytotoxicity against DU-145 and PC3 prostate cancer cell lines over a concentration range of 48 μg/mL-12 μg/mL, while they were biocompatible over a concentration range of 3.0 μg/mL-0.185 μg/mL. Furthermore, PDA-nanoconjugates demonstrated possible anti-invasion activity towards prostate cancer cell lines, particularly DU-145 cell line, by reducing cell migration and cell adhesion properties. The PDA-nanoconjugates could be considered a promising nano-platform toward cancer treatment by reducing the invasion activity; it could also be considered a drug delivery system for chemotherapeutic agents.