Surface Functionalization of Gold Nanoparticles for Targeting the Tumor Microenvironment to Improve Antitumor Efficiency

Raspberry-like gold nano-conjugates of block copolymer prodrug based bicontinuous nanoparticles for cancer theranostics

Theranostic nanoparticles like polymer conjugated gold nanoparticles are at the cutting edge of cancer therapy, offering an integrated platform for simultaneous diagnosis and treatment. In this study, we report a nanoconjugate (P2AuNPs) by combining doxorubicin (DOX) tethered polymeric prodrug based bicontinuous nanoparticles (P2NPs), developed recently by us, with gold nanoparticles (AuNPs). The AuNPs were generated by in situ reduction of HAuCl4, where different polymer functionalities served the role of reducing and stabilizing agents. The bicontinuous morphology of P2NPs provided a unique template for the growth of gold nanoparticles, resulting in an overall raspberry-like morphology. Compared to existing small-sized theranostic AuNPs, which often trigger systematic cytotoxicity, the synthesized P2AuNPs had an ideal size of ∼90 nm for passive targeting of cancer cells through leaky tumor blood vessels. Furthermore, the embedded gold nanoparticles in P2AuNPs nanoconjugate served as a nanometal surface energy transfer (NSET) pair with the covalently attached DOX molecules, resulting in the significant quenching of DOX (turned 'OFF' state) fluorescence at physiological pH (7.4) as confirmed through steady-state and time-resolved fluorescence measurements. It was also possible to recover the quenched DOX fluorescence (turned 'ON' state) with the release of DOX selectively in cancer cell lines, plausibly due to higher glutathione (GSH) levels and acidic pH. In vitro cellular studies asserted the safe nature of P2NPs against non-cancerous cells (HEK-293T) while exhibiting significantly higher drug-induced cytotoxicity against cancerous cells (MCF-7) compared to free DOX. Moreover, when P2AuNPs were incubated with HEK-293T and MCF-7 cells, a fluorescence turn 'ON' for DOX was observed only in MCF-7 cells after the release of DOX, thereby providing an opportunity to improve the sensitivity of imaging and real-time monitoring of drug release. Together, this integrated theranostic system not only has the potential to enhance the precision and effectiveness of cancer therapy but also offers improved monitoring capabilities, representing a significant advancement in tailored nanomedicine.

Predictors of Radiation Resistance and Novel Radiation Sensitizers in Head and Neck Cancers: Advancing Radiotherapy Efficacy

Radiation resistance in head and neck squamous cell carcinoma (HNSCC), driven by intrinsic and extrinsic factors, poses a significant challenge in radiation oncology. The key contributors are tumor hypoxia, cancer stem cells, cell cycle checkpoint activation, and DNA repair processes (homologous recombination and non-homologous end-joining). Genetic modifications such as TP53 mutations, KRAS mutations, EGFR overexpression, and abnormalities in DNA repair proteins like BRCA1/2 additionally affect radiation sensitivity. Novel radiosensitizers targeting these pathways demonstrate the potential to overcome resistance. Hypoxia-activated drugs and gold nanoparticles enhance the efficacy of radiotherapy and facilitate targeted distribution. Integrating immunotherapy, especially immune checkpoint inhibitors, with radiation therapy, enhances anti-tumor responses and reduces resistance. Epigenetic alterations, such as DNA methylation and histone acetylation, significantly influence radiation response, with the potential for sensitization through histone deacetylase inhibitors and non-coding RNA regulators. Metabolic changes linked to glucose, lipid, and glutamine metabolism influence radiosensitivity, uncovering new targets for radiosensitization. Human papillomavirus (HPV)-associated malignancies exhibit increased radiosensitivity relative to other tumors due to impaired DNA repair mechanisms and heightened immunogenicity. Furthermore, understanding the interplay between HPV oncoproteins and p53 functionality can enhance treatment strategies for HPV-related cancers. Using DNA damage response inhibitors (PARP, ATM/ATR), cell cycle checkpoint inhibitors (WEE1, CHK1/2), and hypoxia-targeted agents as radiosensitizing strategies exhibit considerable promise. Immunomodulatory approaches, including PD-1 and CTLA-4 inhibitors in conjunction with radiation, enhance anti-tumor immunity. Future directions emphasize personalized radiation therapy using genetics, sophisticated medication delivery systems, adaptive radiotherapy, and real-time monitoring. These integrated strategies seek to diminish radiation resistance and improve therapeutic efficacy in HNSCC.

Advances in nanotechnology for targeting cancer-associated fibroblasts: A review of multi-strategy drug delivery and preclinical insights

Cancer-associated fibroblasts (CAFs) play a crucial role in the tumor microenvironment by promoting tumor growth, immune evasion, and metastasis. Recently, drug delivery systems targeting CAFs have emerged as a promising long-term and effective approach to cancer treatment. Advances in nanotechnology, in particular, have led to the development of nanomedicine delivery systems designed specifically to target CAFs, offering new possibilities for precise and personalized cancer therapies. This article reviews recent progress in drug delivery using nanocarriers that target CAFs. Additionally, we explore the potential of combining multiple therapies, such as chemotherapy and immunotherapy, with nanocarriers to enhance efficacy and overcome drug resistance. Although many preclinical studies show promise, the clinical application of nanomedicine still faces considerable challenges, especially in terms of drug penetration and large-scale production. Therefore, this review aims to provide a fresh perspective on CAF-targeted drug delivery systems and highlight potential future research directions and clinical applications.

Exploring the Potential of Gold Nanoparticles in Proton Therapy: Mechanisms, Advances, and Clinical Horizons

Proton therapy represents a groundbreaking advancement in cancer radiotherapy, leveraging the unique spatial energy distribution of protons to deliver precise, high-dose radiation to tumors while sparing surrounding healthy tissues. Despite its clinical success, proton therapy faces challenges in optimizing its therapeutic precision and efficacy. Recent research has highlighted the potential of gold nanoparticles to enhance proton therapy outcomes. Due to their high atomic number and favorable biological properties, gold nanoparticles act as radiosensitizers by amplifying the generation of secondary electrons and reactive oxygen species upon proton irradiation. This enhances DNA damage in tumor cells while preserving healthy tissues. Additionally, functionalization of gold nanoparticles with tumor-targeting ligands offers improved precision, making proton therapy more effective against a broader range of cancers. This review synthesizes current knowledge on the mechanisms of gold nanoparticle radiosensitization, preclinical evidence, and the technological hurdles that must be addressed to integrate this promising approach into clinical practice, aiming to advance the efficacy and accessibility of proton therapy in cancer therapy.

Gold nanocomposites in colorectal cancer therapy: characterization, selective cytotoxicity, and migration inhibition

The third most prevalent type of cancer in the world, colorectal cancer, poses a significant treatment challenge due to the nonspecific distribution, low efficacy, and high systemic toxicity associated with chemotherapy. To overcome these limitations, a targeted drug delivery system with a high cytotoxicity against cancer cells while maintaining a minimal systemic side effects represents a promising therapeutic approach. Therefore, the aim of this study was to develop an efficient gold nanocarrier for the targeted delivery of the anticancer agent everolimus to Caco-2 cells. A novel gold nanocomposite (EV-β-CD-HA-Chi-AuNCs) functionalized with a targeting ligand (hyaluronic acid), a permeation enhancement excipient (chitosan), and an anticancer inclusive compound consisting of beta-cyclodextrin and everolimus was proposed and prepared via Turkevich method. Characterization was performed with a UV spectrometer, FTIR, Zetasizer, and HRTEM. Its drug release profile was also evaluated in media with three different pH values. Cytotoxicity and biocompatibility studies were performed on a colorectal cancer cell line (Caco-2) and a normal fibroblast line (MRC-5), respectively, via xCELLigence real-time cellular analysis (RTCA) technology. The inhibitory effect on migration was also further tested via the xCELLigence RTCA technique and a scratch assay. Characterization studies revealed the successful formation of EV-β-CD-HA-Chi-AuNCs with a size and charge which are suitable for the use as targeted drug delivery carrier. In the cytotoxic study, the EV-β-CD-HA-Chi-AuNCs showed a lower IC50 (16 ± 1 µg/ml) than the pure drug (25 ± 3 µg/ml) toward a colorectal cell line (Caco-2). In the biocompatibility study, the EV-β-CD-HA-Chi-AuNCs have minimal toxicity, while the pure drug has severe toxicity toward healthy fibroblasts (MRC-5) despite its low concentration. In the cell migration study, the EV-β-CD-HA-Chi-AuNCs also showed a greater inhibitory effect than the pure drug. Compared with the pure drug, the EV-β-CD-HA-Chi-AuNCs exhibit an excellent selective cytotoxicity between cancerous colorectal Caco-2 cells and healthy MRC-5 cells, making it a potential carrier to carry the drug to the cancerous site while maintaining its low toxicity to the surrounding environment. In addition, an increase in the cytotoxic activity of the EV-β-CD-HA-Chi-AuNCs toward cancerous colorectal Caco-2 cells was also observed, which can potentially improve the treatment of colorectal cancer.

Influence of Gold Nanoparticles on eNOS Localization in Gill Tissues: Advancements in Immunofluorescence Techniques

This study optimizes immunofluorescence techniques using gold nanoparticles (AuNPs) to improve visualization of endothelial nitric oxide synthase (eNOS) in gill tissue. Two types of AuNP dispersions, stabilized in phosphate buffered saline (PBS) and citrate buffer (CB), were evaluated for their imaging performance. AuNPs suspended in PBS provided significantly better optical contrast due to uniform distribution and effective tissue attachment, whereas citrate-suspended AuNPs exhibited aggregation, resulting in reduced contrast. These results highlight the influence of suspension media on AuNP performance, particularly in balancing fluorescence signals to improve contrast. The PBS suspension allowed clearer visualization of eNOS, highlighting the role of AuNP compatibility in improving immunofluorescence results. This study highlights the importance of strategic selection of AuNP dispersions in contrast agent design and provides insights for advanced imaging applications where sensitivity and accurate localization of biomolecules are essential. By refining the use of AuNPs as contrast enhancers, this approach offers potential improvements in bioimaging accuracy, facilitating more precise visualization in complex tissue environments.

Biomimetic Cell Membrane-Coated Nanoparticles for Cancer Theranostics

Nanoparticles can enhance drugs accumulating at the tumor site and hold tremendous promise for achieving effective tumor treatment. However, due to the complexity of cancer heterogeneity and suppressive tumor microenvironment, the delivery of traditional nanoparticles has poor infiltration and off-target effects, making it difficult to control the drug release rate and causing off-target toxicity. In recent years, cell membrane-coated biomimetic nanoparticles have been developed, which have both the natural characteristics of biomembranes and the physical characteristics of traditional nanoparticles, thus improving the homologous targeting ability of nanoparticles to tumor cells and better biocompatibility. In this paper, we reviewed the application of single cell membrane and hybrid cell membrane-coated biomimetic nanoparticles in the integration for tumor diagnosis and treatment. We talked about the preparation methods of cell membrane-coated nanoparticles, the targeting mechanisms, and the effects of imaging and therapeutic outcomes of different cell membrane-coated biomimetic nanoparticles in detail. Finally, we discussed the existing problems and prospects of cell membrane-coated biomimetic nanomaterials.

Green synthesis of anti-cancer drug-loaded gold nanoparticles for low-intensity pulsed ultrasound targeted drug release

In the present work, we have designed a one-pot green protocol in which anti-cancer drugs (curcumin and doxorubicin) can be directly loaded on the surface of gold nanoparticles during their formation. We have further demonstrated that low-intensity pulsed ultrasound (LIPUS) can be used to effectively induce the release of anti-cancer drugs from the surface of gold nanoparticles in an ex vivo tissue model. With this protocol, gold nanoparticles can be easily loaded with different types of anticancer drugs, irrespective of their affinity towards water, and even hydrophobic molecules, like curcumin, can be attached onto the gold nanoparticles in an aqueous medium. The method is very simple and straightforward and does not require stirring or mechanical shaking. The drug molecules interact with the gold seeds formed during the reduction and growth process and modulate the final morphology into a spherical shape. A black-colored colloidal solution of gold nanowire networks is formed in the absence of these anti-cancer drug molecules in the reaction mixture. We used hyperspectral-enhanced dark field microscopy to examine the uptake of gold nanoparticles by breast cancer cells. Upon exposure to LIPUS, the release of the anti-cancer drug from the particle surface can be quantified by fluorescence measurements. This release of drug molecules along with trisodium citrate from the surface of gold nanoparticles by ultrasound resulted in their destabilization and subsequent aggregation, which could be visually observed through the change in the color of colloidal sol. Cancer cell viability was studied by MTT assay to examine the efficacy of this nanoparticle-based drug delivery system. Ultraviolet-visible spectroscopy, dynamic light scattering (DLS), and transmission electron microscope (TEM) analysis were used to characterize the nanoparticles and quantify anti-cancer drug release.

Clinical translation of nanomedicine with integrated digital medicine and machine learning interventions

Nanomaterials based therapeutics transform the ways of disease prevention, diagnosis and treatment with increasing sophistications in nanotechnology at a breakneck pace, but very few could reach to the clinic due to inconsistencies in preclinical studies followed by regulatory hinderances. To tackle this, integrating the nanomedicine discovery with digital medicine provide technologies as tools of specific biological activity measurement. Hence, overcome the redundancies in nanomedicine discovery by the on-site data acquisition and analytics through integrating intelligent sensors and artificial intelligence (AI) or machine learning (ML). Integrated AI/ML wearable sensors directly gather clinically relevant biochemical information from the subject's body and process data for physicians to make right clinical decision(s) in a time and cost-effective way. This review summarizes insights and recommend the infusion of actionable big data computation enabled sensors in burgeoning field of nanomedicine at academia, research institutes, and pharmaceutical industries, with a potential of clinical translation. Furthermore, many blind spots are present in modern clinically relevant computation, one of which could prevent ML-guided low-cost new nanomedicine development from being successfully translated into the clinic was also discussed.

Gold Nanoparticles in Nanobiotechnology: From Synthesis to Biosensing Applications

Nanobiotechnology has ushered in a new era of scientific discovery where the unique properties of nanomaterials, such as gold nanoparticles, have been harnessed for a wide array of applications. This review explores gold nanoparticles' synthesis, properties, and multidisciplinary applications, focusing on their role as biosensors. Gold nanoparticles possess exceptional physicochemical attributes, including size-dependent optical properties, biocompatibility, and ease of functionalization, making them promising candidates for the development of biosensing platforms. The review begins by providing a comprehensive overview of gold nanoparticle synthesis techniques, highlighting the advantages and disadvantages of various approaches. It then delves into the remarkable properties that underpin their success in biosensing, such as localized surface plasmon resonance and enhanced surface area. The discussion also includes the functionalization strategies that enable specific binding to biomolecules, enhancing the sensitivity and selectivity of gold-nanoparticle-based biosensors. Furthermore, this review surveys the diverse applications of gold nanoparticles in biosensing, encompassing diagnostics, environmental monitoring, and drug delivery. The multidisciplinary nature of these applications underscores the versatility and potential of gold nanoparticles in addressing complex challenges in healthcare and environmental science. The review emphasizes the pressing need for further exploration and research in the field of nanobiotechnology, particularly regarding the synthesis, properties, and biosensing applications of gold nanoparticles. With their exceptional physicochemical attributes and versatile functionalities, gold nanoparticles present a promising avenue for addressing complex challenges in healthcare and environmental science, making it imperative to advance our understanding of their synthesis, properties, and applications for enhanced biosensing capabilities and broader scientific innovation.

[18F]-Radiolabelled Nanoplatforms: A Critical Review of Their Intrinsic Characteristics, Radiolabelling Methods, and Purification Techniques

A wide range of nano-objects is found in many applications of our everyday life. Recognition of their peculiar properties and ease of functionalization has prompted their engineering into multifunctional platforms that are supposed to afford efficient tools for the development of biomedical applications. However, bridging the gap between bench to bedside cannot be expected without a good knowledge of their behaviour in vivo, which can be obtained through non-invasive imaging techniques, such as positron emission tomography (PET). Their radiolabelling with [18F]-fluorine, a technique already well established and widely used routinely for PET imaging, with [18F]-FDG for example, and in preclinical investigation using [18F]-radiolabelled biological macromolecules, has, therefore, been developed. In this context, this review highlights the various nano-objects studied so far, the reasons behind their radiolabelling, and main in vitro and/or in vivo results obtained thereof. Then, the methods developed to introduce the radioelement are presented. Detailed indications on the chemical steps involved are provided, and the stability of the radiolabelling is discussed. Emphasis is then made on the techniques used to purify and analyse the radiolabelled nano-objects, a point that is rarely discussed despite its technical relevance and importance for accurate imaging. The pros and cons of the different methods developed are finally discussed from which future work can develop.

Gold Nanoparticles Downregulate IL-6 Expression/Production by Upregulating microRNA-26a-5p and Deactivating the RelA and NF-κBp50 Transcription Pathways in Activated Breast Cancer Cells

MicroRNAs (miRNAs) are involved in the modulation of pathogenic genes by binding to their mRNA sequences' 3' untranslated regions (3'UTR). Interleukin-6 (IL-6) is known to promote cancer progression and treatment resistance. In this study, we aimed to explore the therapeutic effects of gold nanoparticles (GNP) against IL-6 overexpression and the modulation of miRNA-26a-5p in breast cancer (BC) cells. GNP were synthesized using the trisodium citrate method and characterized through UV-Vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). To predict the binding of miR-26a-5p in the IL-6 mRNA's 3'UTR, we utilized bioinformatics algorithms. Luciferase reporter clone assays and anti-miRNA-26a-5p transfection were employed to validate the binding of miR26a-5p in the IL-6 mRNA's 3'UTR. The activity of RelA and NF-κBp50 was assessed and confirmed using Bay 11-7082. The synthesized GNP were spherical with a mean size of 28.3 nm, exhibiting high stability, and were suitable for BC cell treatment. We found that miR-26a-5p directly regulated IL-6 overexpression in MCF-7 cells activated with PMA. Treatment of MCF-7 cells with GNP resulted in the inhibition of IL-6 overexpression and secretion through the increase of miR26a-5p. Furthermore, GNP deactivated NF-κBp65/NF-κBp50 transcription activity. The newly engineered GNP demonstrated safety and showed promise as a therapeutic approach for reducing IL-6 overexpression. The GNP suppressed IL-6 overexpression and secretion by deactivating NF-κBp65/NF-κBp50 transcription activity and upregulating miR-26a-5p expression in activated BC cells. These findings suggest that GNP have potential as a therapeutic intervention for BC by targeting IL-6 expression and associated pathways.

Role of Functionalized Peptides in Nanomedicine for Effective Cancer Therapy

Peptide-functionalized nanomedicine, which addresses the challenges of specificity and efficacy in drug delivery, is emerging as a pivotal approach for cancer therapy. Globally, cancer remains a leading cause of mortality, and conventional treatments, such as chemotherapy, often lack precision and cause adverse effects. The integration of peptides into nanomedicine offers a promising solution for enhancing the targeting and delivery of therapeutic agents. This review focuses on the three primary applications of peptides: cancer cell-targeting ligands, building blocks for self-assembling nanostructures, and elements of stimuli-responsive systems. Nanoparticles modified with peptides improved targeting of cancer cells, minimized damage to healthy tissues, and optimized drug delivery. The versatility of self-assembled peptide structures makes them an innovative vehicle for drug delivery by leveraging their biocompatibility and diverse nanoarchitectures. In particular, the mechanism of cell death induced by self-assembled structures offers a novel approach to cancer therapy. In addition, peptides in stimuli-responsive systems enable precise drug release in response to specific conditions in the tumor microenvironment. The use of peptides in nanomedicine not only augments the efficacy and safety of cancer treatments but also suggests new research directions. In this review, we introduce systems and functionalization methods using peptides or peptide-modified nanoparticles to overcome challenges in the treatment of specific cancers, including breast cancer, lung cancer, colon cancer, prostate cancer, pancreatic cancer, liver cancer, skin cancer, glioma, osteosarcoma, and cervical cancer.

Smart Magnetic Nanocarriers for Codelivery of Nitric Oxide and Doxorubicin for Enhanced Apoptosis in Cancer Cells

Extremely short half-life therapeutic molecule nitric oxide (NO) plays significant roles in the functioning of various physiological and pathological processes in the human body, whereas doxorubicin hydrochloride (DOX) is a clinically important anticancer drug widely used in cancer chemotherapy. Thus, the intracellular delivery of these therapeutic molecules is tremendously important to achieve their full potential. Herein, we report a novel approach for the development of highly water-dispersible magnetic nanocarriers for codelivery of NO and DOX. Primarily, bifunctional magnetic nanoparticles enriched with carboxyl and thiol groups were prepared by introducing cysteine onto the surface of citrate-functionalized Fe3O4 nanoparticles. DOX was electrostatically conjugated onto the surface of bifunctional nanoparticles via carboxyl moieties, whereas the thiol group was further nitrosated to provide NO-releasing molecules. The developed magnetic nanocarrier exhibited good aqueous colloidal stability, protein resistance behavior, and high encapsulation efficacy for NO (65.5%) and DOX (85%), as well as sustained release characteristics. Moreover, they showed superior cytotoxicity toward cancer (A549 and MCF-7) cells via apoptosis induction over normal (WI26VA4) cells. Specifically, we have developed magnetic nanocarriers having the capability of dual delivery of NO and DOX, which holds great potential for combinatorial cancer treatment.