Gold nanoparticles in chemo-, immuno-, and combined therapy: review [Invited]

Efficient production of uniform gold nanoparticles via a streamlined low-cost, semi-automated, open-source platform

In the quest to discover dependable and repeatable methods for producing noble metal nanospheres, both commercial and academic scientists have shown great interest. The challenge of precisely controlling the size of these nanospheres is critical, as variations can alter their optical characteristics, leading to complications in subsequent applications. In this context, we present the design and validation of an affordable, semi-automated device that synthesizes gold nanoparticles using the Turkevich method. This device, named 'NanoSynth Mini' and powered by Raspberry Pi, demonstrates the capability to generate gold nanoparticles with diameters ranging from 15 to 60 nanometers with minimal variability. Its design allows for seamless integration into lab processes, providing consistent support for extensive research initiatives.

Adjuvant Novel Nanocarrier-Based Targeted Therapy for Lung Cancer

Lung cancer has the lowest survival rate due to its late-stage diagnosis, poor prognosis, and intra-tumoral heterogeneity. These factors decrease the effectiveness of treatment. They release chemokines and cytokines from the tumor microenvironment (TME). To improve the effectiveness of treatment, researchers emphasize personalized adjuvant therapies along with conventional ones. Targeted chemotherapeutic drug delivery systems and specific pathway-blocking agents using nanocarriers are a few of them. This study explored the nanocarrier roles and strategies to improve the treatment profile's effectiveness by striving for TME. A biofunctionalized nanocarrier stimulates biosystem interaction, cellular uptake, immune system escape, and vascular changes for penetration into the TME. Inorganic metal compounds scavenge reactive oxygen species (ROS) through their photothermal effect. Stroma, hypoxia, pH, and immunity-modulating agents conjugated or modified nanocarriers co-administered with pathway-blocking or condition-modulating agents can regulate extracellular matrix (ECM), Cancer-associated fibroblasts (CAF),Tyro3, Axl, and Mertk receptors (TAM) regulation, regulatory T-cell (Treg) inhibition, and myeloid-derived suppressor cells (MDSC) inhibition. Again, biomimetic conjugation or the surface modification of nanocarriers using ligands can enhance active targeting efficacy by bypassing the TME. A carrier system with biofunctionalized inorganic metal compounds and organic compound complex-loaded drugs is convenient for NSCLC-targeted 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.

Applications of Green Synthesized Metal Nanoparticles - a Review

Green nanotechnology is an emerging field of science that focuses on the production of nanoparticles by living cells through biological pathways. This topic plays an extremely imperative responsibility in various fields, including pharmaceuticals, nuclear energy, fuel and energy, electronics, and bioengineering. Biological processes by green synthesis tools are more suitable to develop nanoparticles ranging from 1 to 100 nm compared to other related methods, owing to their safety, eco-friendliness, non-toxicity, and cost-effectiveness. In particular, the metal nanoparticles are synthesized by top-down and bottom-up approaches through various techniques like physical, chemical, and biological methods. Their characterization is very vital and the confirmation of nanoparticle traits is done by various instrumentation analyses such as UV-Vis spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM), annular dark-field imaging (HAADF), and intracranial pressure (ICP). In this review, we provide especially information on green synthesized metal nanoparticles, which are helpful to improve biomedical and environmental applications. In particular, the methods and conditions of plant-based synthesis, characterization techniques, and applications of green silver, gold, iron, selenium, and copper nanoparticles are overviewed.

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.

Tunable-wavelength nanosecond laser tailoring of plasmon resonance spectra of gold nanoparticle colloids

Metal nanoparticles have applications across a range of fields of science and industry. While there are numerous existing methods to facilitate their large-scale production, most face limitations, particularly in achieving reproducible processes and minimizing undesirable impurities. Common issues are varying particle sizes and aggregates with unfavorable spectral properties. Researchers are currently developing methods to separate or modify nanoparticle sizes and shapes post-synthesis and to eliminate impurities. One promising approach involves laser light irradiation and enables the changing of nanoparticle sizes and shapes while controlling crucial spectral parameters. In this work, we present a novel extension of this method by irradiating nanoparticle colloids with variable-wavelength nanosecond laser pulses on both sides of the extinction band. Our results demonstrate the use of gradual laser wavelength tuning to optimize the photothermal reshaping of gold nanorods and achieve precise control over the plasmon resonance band. By irradiating both sides of the plasmon resonance band, we execute a multistep tuning process, controlling the band's width and spectral position. A statistical analysis of SEM images reveals differences in the nanorod morphology when irradiated on the long- or short-wavelength side of the plasmon resonance band. The fine-tuning of plasmonic spectral properties is desirable for various applications, including the development of sensors and filters and the exploitation of the photothermal effect. The findings of this study can be extended to other plasmonic nanostructures.

The Dawn of a New Era: Targeting the "Undruggables" with Antibody-Based Therapeutics

The high selectivity and affinity of antibodies toward their antigens have made them a highly valuable tool in disease therapy, diagnosis, and basic research. A plethora of chemical and genetic approaches have been devised to make antibodies accessible to more "undruggable" targets and equipped with new functions of illustrating or regulating biological processes more precisely. In this Review, in addition to introducing how naked antibodies and various antibody conjugates (such as antibody-drug conjugates, antibody-oligonucleotide conjugates, antibody-enzyme conjugates, etc.) work in therapeutic applications, special attention has been paid to how chemistry tools have helped to optimize the therapeutic outcome (i.e., with enhanced efficacy and reduced side effects) or facilitate the multifunctionalization of antibodies, with a focus on emerging fields such as targeted protein degradation, real-time live-cell imaging, catalytic labeling or decaging with spatiotemporal control as well as the engagement of antibodies inside cells. With advances in modern chemistry and biotechnology, well-designed antibodies and their derivatives via size miniaturization or multifunctionalization together with efficient delivery systems have emerged, which have gradually improved our understanding of important biological processes and paved the way to pursue novel targets for potential treatments of various diseases.

Cerium End-Deposited Gold Nanorods-Based Photoimmunotherapy for Boosting Tumor Immunogenicity

BACKGROUND

Triple-negative breast cancer (TNBC) was closely related to high metastatic risk and mortality and has not yet found a targeted receptor for targeted therapy. Cancer immunotherapy, especially photoimmunotherapy, shows promising potential in TNBC treatment because of great spatiotemporal controllability and non-trauma. However, the therapeutic effectiveness was limited by insufficient tumor antigen generation and the immunosuppressive microenvironment.

METHODS

We report on the design of cerium oxide (CeO₂) end-deposited gold nanorods (CEG) to achieve excellent near-infrared photoimmunotherapy. CEG was synthesized through hydrolyzing of ceria precursor (cerium acetate, Ce(AC)₃) on the surface of Au nanorods (NRs) for cancer therapy. The therapeutic response was first verified in murine mammary carcinoma (4T1) cells and then monitored by analysis of the anti-tumor effect in xenograft mouse models.

RESULTS

Under near-infrared (NIR) light irradiation, CEG can efficiently generate hot electrons and avoid hot-electron recombination to release heat and form reactive oxygen species (ROS), triggering immunogenic cell death (ICD) and activating part of the immune response. Simultaneously, combining with PD-1 antibody could further enhance cytotoxic T lymphocyte infiltration.

CONCLUSIONS

Compared with CBG NRs, CEG NRs showed strong photothermal and photodynamic effects to destroy tumors and activate a part of the immune response. Combining with PD-1 antibody could reverse the immunosuppressive microenvironment and thoroughly activate the immune response. This platform demonstrates the superiority of combination therapy of photoimmunotherapy and PD-1 blockade in TNBC therapy.

Evolution of Gold and Iron Oxide Nanoparticles in Conjugates with Methotrexate: Synthesis and Anticancer Effects

Au and Fe nanoparticles and their conjugates with the drug methotrexate were obtained by an environmentally safe method of metal-vapor synthesis (MVS). The materials were characterized by transmission and scanning electron microscopy (TEM, SEM), X-ray photoelectron spectroscopy (XPS), and small-angle X-ray scattering using synchrotron radiation (SAXS). The use of acetone as an organic reagent in the MVS makes it possible to obtain Au and Fe particles with an average size of 8.3 and 1.8 nm, respectively, which was established by TEM. It was found that Au, both in the NPs and the composite with methotrexate, was in the Au⁰, Au⁺ and Au³⁺ states. The Au 4f spectra for Au-containing systems are very close. The effect of methotrexate was manifested in a slight decrease in the proportion of the Au⁰ state-from 0.81 to 0.76. In the Fe NPs, the main state is the Fe³⁺ state, and the Fe²⁺ state is also present in a small amount. The analysis of samples by SAXS registered highly heterogeneous populations of metal nanoparticles coexisting with a wide proportion of large aggregates, the number of which increased significantly in the presence of methotrexate. For Au conjugates with methotrexate, a very wide asymmetric fraction with sizes up to 60 nm and a maximum of ~4 nm has been registered. In the case of Fe, the main fraction consists of particles with a radius of 4.6 nm. The main fraction consists of aggregates up to 10 nm. The size of the aggregates varies in the range of 20-50 nm. In the presence of methotrexate, the number of aggregates increases. The cytotoxicity and anticancer activity of the obtained nanomaterials were determined by MTT and NR assays. Fe conjugates with methotrexate showed the highest toxicity against the lung adenocarcinoma cell line and Au nanoparticles loaded with methotrexate affected the human colon adenocarcinoma cell line. Both conjugates displayed lysosome-specific toxicity against the A549 cancer cell line after 120 h of culture. The obtained materials may be promising for the creation of improved agents for cancer treatment.

18F-fluorodeoxyglucose (18F-FDG) Functionalized Gold Nanoparticles (GNPs) for Plasmonic Photothermal Ablation of Cancer: A Review

The meeting and merging between innovative nanotechnological systems, such as nanoparticles, and the persistent need to outperform diagnostic-therapeutic approaches to fighting cancer are revolutionizing the medical research scenario, leading us into the world of nanomedicine. Photothermal therapy (PTT) is a non-invasive thermo-ablative treatment in which cellular hyperthermia is generated through the interaction of near-infrared light with light-to-heat converter entities, such as gold nanoparticles (GNPs). GNPs have great potential to improve recovery time, cure complexity, and time spent on the treatment of specific types of cancer. The development of gold nanostructures for photothermal efficacy and target selectivity ensures effective and deep tissue-penetrating PTT with fewer worries about adverse effects from nonspecific distributions. Regardless of the thriving research recorded in the last decade regarding the multiple biomedical applications of nanoparticles and, in particular, their conjugation with drugs, few works have been completed regarding the possibility of combining GNPs with the cancer-targeted pharmaceutical fluorodeoxyglucose (FDG). This review aims to provide an actual scenario on the application of functionalized GNP-mediated PTT for cancer ablation purposes, regarding the opportunity given by the 18F-fluorodeoxyglucose (18F-FDG) functionalization.

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.

Nanoplasmonics Enabling Cancer Diagnostics and Therapy

In this paper, we highlight several advances our laboratory has developed in the pursuit of cancer diagnostics and therapeutics by integrating plasmonics, photonics, and nanotechnology. We discuss the development and applications of plasmonics-active gold nanostar (GNS), a uniquely shaped nanoparticle with numerous branches that serve to greatly amplify the thermal generation at resonant wavelengths. GNS has also been successfully used in tumor imaging contexts from two-photon fluorescence to surface-enhanced Raman scattering (SERS) sensing and imaging. Finally, GNS has been coupled with immunotherapy applications to serve as an effective adjuvant to immune checkpoint inhibitors. This combination of GNS and immunotherapy, the so called synergistic immuno photo nanotherapy (SYMPHONY), has been shown to be effective at controlling long-lasting cancer immunity and metastatic tumors.

Ruthenium-based antitumor drugs and delivery systems from monotherapy to combination therapy

Ruthenium complex is an important compound group for antitumor drug research and development. NAMI-A, KP1019, TLD1433 and other ruthenium complexes have entered clinical research. In recent years, the research on ruthenium antitumor drugs has not been limited to single chemotherapy drugs; other applications of ruthenium complexes have emerged such as in combination therapy. During the development of ruthenium complexes, drug delivery forms of ruthenium antitumor drugs have also evolved from single-molecule drugs to nanodrug delivery systems. The review summarizes the following aspects: (1) ruthenium complexes from monotherapy to combination therapy, including the development of single-molecule compounds, carrier nanomedicine, and self-assembly of carrier-free nanomedicine; (2) ruthenium complexes in the process of ADME in terms of absorption, distribution, metabolism and excretion; (3) the applications of ruthenium complexes in combination therapy, including photodynamic therapy (PDT), photothermal therapy (PTT), photoactivated chemotherapy (PACT), immunotherapy, and their combined application; (4) the future prospects of ruthenium-based antitumor drugs.

Nonmetal-to-Metal Transition of Magnesia Supported Au Clusters Affects the Ultrafast Dissociation Dynamics of Adsorbed CH3Br Molecules

The detection of intermediate species and the correlation of their ultrafast dynamics with the morphology and electronic structure of a surface is crucial to fully understand and control heterogeneous photoinduced and photocatalytic reactions. In this work, the ultrafast photodissociation dynamics of CH₃Br molecules adsorbed on variable-size Au clusters on MgO/Mo(100) is investigated by monitoring the CH₃⁺ transient evolution using a pump-probe technique in conjunction with surface mass spectrometry. Furthermore, extreme-UV photoemission spectroscopy in combination with theoretical calculations is employed to study the electronic structure of the Au clusters on MgO/Mo(100). Changes in the ultrafast dynamics of the CH₃⁺ fragment are correlated with the electronic structure of Au as it evolves from monomers to small nonmetallic clusters to larger nanoparticles with a metallic character. This work provides a new avenue to a detailed understanding of how surface-photoinduced chemical reactions are influenced by the composition and electronic structure of the surface.

Inorganic Nanoparticles in Bone Healing Applications

Modern biomedicine aims to develop integrated solutions that use medical, biotechnological, materials science, and engineering concepts to create functional alternatives for the specific, selective, and accurate management of medical conditions. In the particular case of tissue engineering, designing a model that simulates all tissue qualities and fulfills all tissue requirements is a continuous challenge in the field of bone regeneration. The therapeutic protocols used for bone healing applications are limited by the hierarchical nature and extensive vascularization of osseous tissue, especially in large bone lesions. In this regard, nanotechnology paves the way for a new era in bone treatment, repair and regeneration, by enabling the fabrication of complex nanostructures that are similar to those found in the natural bone and which exhibit multifunctional bioactivity. This review aims to lay out the tremendous outcomes of using inorganic nanoparticles in bone healing applications, including bone repair and regeneration, and modern therapeutic strategies for bone-related pathologies.

OxyChip embedded with radio-opaque gold nanoparticles for anatomic registration and oximetry in tissues

PURPOSE

Electron paramagnetic resonance oximetry using the OxyChip as an implantable oxygen sensor can directly and repeatedly measure tissue oxygen levels. A phase I, first-in-human clinical study has established the safety and feasibility of using OxyChip for reliable and repeated measurements of oxygen levels in a variety of tumors and treatment regimens. A limitation in these studies is the inability to easily locate and identify the implanted probes in the tissue, particularly in the long term, thus limiting spatial/anatomical registration of the implant for proper interpretation of the oxygen data. In this study, we have developed and evaluated an enhanced oxygen-sensing probe embedded with gold nanoparticles (GNP), called the OxyChip-GNP, to enable visualization of the sensor using routine clinical imaging modalities.

METHODS

In vitro characterization, imaging, and histopathology studies were carried out using tissue phantoms, excised tissues, and in vivo animal models (mice and rats).

RESULTS

The results demonstrated a substantial enhancement of ultrasound and CT contrast using the OxyChip-GNP without compromising its electron paramagnetic resonance and oxygen-sensing properties or biocompatibility.

CONCLUSIONS

The OxyChips embedded with gold nanoparticles (OxyChip-GNP) can be readily identified in soft tissues using standard clinical imaging modalities such as CT, cone beam-CT, or ultrasound imaging while maintaining its capability to make repeated in vivo measurements of tissue oxygen levels over the long term. This unique capability of the OxyChip-GNP facilitates precisely localized in vivo oxygen measurements in the clinical setting.

Silver and Gold Nanoparticles for Antimicrobial Purposes against Multi-Drug Resistance Bacteria

Several pieces of research have been done on transition metal nanoparticles and their nanocomplexes as research on their physical and chemical properties and their relationship to biological features are of great importance. Among all their biological properties, the antibacterial and antimicrobial are especially important due to their high use for human needs. In this article, we will discuss the different synthesis and modification methods of silver (Ag) and gold (Au) nanoparticles and their physicochemical properties. We will also review some state-of-art studies and find the best relationship between the nanoparticles’ physicochemical properties and potential antimicrobial activity. The possible antimicrobial mechanism of these types of nanoparticles will be discussed in-depth as well.

Novel Green Approaches for the Preparation of Gold Nanoparticles and Their Promising Potential in Oncology

The difficulty of achieving targeted drug delivery following administration of currently marketed anticancer therapeutics is a still a concern. Metallic nanoparticles (NPs) developed through nanotechnology breakthroughs appear to be promising in this regard. Research studies pertaining to gold NPs have indicated their promising applicability in cancer diagnosis, drug delivery and therapy. These NPs have also recently paved the path for precise drug delivery and site-specific targeting. Our review paper thus highlights the scope and impact of biogenetically generated gold nanoparticles (NPs) in cancer therapy. In a critical, constructive, and methodical manner, we compare the advantages offered by gold NPs over other metal NPs. Moreover, we also focus on novel ‘greener’ strategies that have been recently explored for the preparation of gold NPs and shed light on the disadvantages of conventional NP synthesis routes. Future prospects pertaining to the use of gold NPs in oncotherapy and domains that require further investigation are also addressed.

Design and Encapsulation of Immunomodulators onto Gold Nanoparticles in Cancer Immunotherapy

The aim of cancer immunotherapy is to reactivate autoimmune responses to combat cancer cells. To stimulate the immune system, immunomodulators, such as adjuvants, cytokines, vaccines, and checkpoint inhibitors, are extensively designed and studied. Immunomodulators have several drawbacks, such as drug instability, limited half-life, rapid drug clearance, and uncontrolled immune responses when used directly in cancer immunotherapy. Several strategies have been used to overcome these limitations. A simple and effective approach is the loading of immunomodulators onto gold-based nanoparticles (GNPs). As gold is highly biocompatible, GNPs can be administered intravenously, which aids in increasing cancer cell permeability and retention time. Various gold nanoplatforms, including nanospheres, nanoshells, nanorods, nanocages, and nanostars have been effectively used in cancer immunotherapy. Gold nanostars (GNS) are one of the most promising GNP platforms because of their unusual star-shaped geometry, which significantly increases light absorption and provides high photon-to-heat conversion efficiency due to the plasmonic effect. As a result, GNPs are a useful vehicle for delivering antigens and adjuvants that support the immune system in killing tumor cells by facilitating or activating cytotoxic T lymphocytes. This review represents recent progress in encapsulating immunomodulators into GNPs for utility in a cancer immunotherapeutic regimen.

Nanoparticle-based fluorescence probe for detection of NF-κB transcription factor in single cell via steric hindrance

A novel nanoparticle-based fluorescence probe was developed for NF-κB transcription factor detection and in situ imaging via steric hindrance. The probe contains gold nanoparticles (AuNPs) to quench fluorescence, and nucleic acids immobilized on the surface of AuNPs to output fluorescence. In the basal state, Cy5 labeled DNA1 folds its long chain into a hairpin structure and quenches fluorescence by forcing the Cy5 fluorophore close to the surface of AuNPs. After the probe enters the cell, the NF-κB transcription factor can bind to the κB site in the DNA duplex of the nucleic acids. The steric hindrance caused by NF-κB leads to the extension of the long chain of DNA1 and the removal of the Cy5 fluorophore from the surface of AuNPs, thereby restoring the fluorescence of the probe. By measuring NF-κB in cell lysis in vitro, the probe obtains a detection limit of 0.38 nM and the linear range from 0.5 to 16 nM. Repeated measurements showed the recovery in the cell nuclear extract was between 93.38 and 109.32%, with relative standard deviation less than 5%. By monitoring the sub-localization of the Cy5 fluorophore in single cell, the probe system can effectively distinguish active NF-κB (nucleus) and inactive NF-κB (cytoplasm) through in situ imaging. The well-designed probe will make up for the shortcomings of the existing technology, and reveal the regulatory role of transcription factors in many disease processes.

Outer Membrane Protein-Coated Nanoparticles as Antibacterial Vaccine Candidates

Nanoformulations are novel therapeutic strategies as compared to traditional treatments. The development of biomimetic nanoparticles by combining the natural cellular material with synthetic nanoparticles has inspired innovative vaccine strategies for modifying the antibacterial immunity. A lot of work has been done in which synthetic nanoparticles are coated with biomimetic cellular membranes for enhancement of biological functions and treatments. Outer membrane protein of bacteria not only act as adjuvant but also contain a large number of immunogenic antigens that play an important role in motivating the native immunity and stimulating the immune responses of the body. Outer membrane protein coating onto the surfaces of synthetic nanoparticles has synergistic effects to produce antibacterial responses. This article reviews the recent improvements related to the bacterial membrane-coated nanoparticles for antibacterial immunization.

Comparative toxicity of green and chemically synthesized CuO NPs during pregnancy and lactation in rats and offspring: Part I -hepatotoxicity

Widespread applications of nanomaterials in food and health sciences have inevitable toxicological outcomes. Among nanomaterials, copper oxide nanoparticles (CuO NPs) are commonly used in all fields due to its distinctive characteristics. The study was designed to investigate the comparative hepatotoxic effect of green (GNPs) and chemically synthesized (CNPs) CuO NPs on spargue-dawely rats and their offspring. NPs (50 and 100 mg/kg) were orally administered to rats twice a week starting before mating. After birth the parents were continued dosing while pups were only on mother feed. Antioxidant, lipid peroxidation, genotoxicity, and histology were performed on liver tissue. In addition serum biochemistry of parents and offspring was also performed. The levels of catalase, peroxidase, and glutathione were significantly lowered only in CNPs treated parents while lipid peroxidation level was increased in these groups. Maximum genotoxicity (2.3%) in terms of percent tail DNA was observed in parent rats administered with high CNPs dose while other groups did not exhibit significant variation in genetoxic parameters. Gender and dose dependent effects were observed on liver function tests especially ALP and ALT in parents however no obvious differences were observed in offspring. Furthermore, dose dependent dilation and congestion of sinusoids was observed on CNPs administration. In GNPs treated rats and offspring histological alterations were observed. The study concludes that chemically synthesized CuO NPs exhibit dose dependent toxic effects on liver as compared to green synthesized CuO NPs. Furthermore lactation does not play significant role in the hepatotoxicity of offspring though minor oxidative stress was observed only on CNPs administration. The study also shows that pharmacological application of green synthesized NPs can be accomplished due to their biocompatible nature.

Effect of Cetuximab-Conjugated Gold Nanoparticles on the Cytotoxicity and Phenotypic Evolution of Colorectal Cancer Cells

Epidermal growth factor receptor (EGFR) is estimated to be overexpressed in 60~80% of colorectal cancer (CRC), which is associated with a poor prognosis. Anti-EGFR targeted monoclonal antibodies (cetuximab and panitumumab) have played an important role in the treatment of metastatic CRC. However, the therapeutic response of anti-EGFR monoclonal antibodies is limited due to multiple resistance mechanisms. With the discovery of new functions for gold nanoparticles (AuNPs), we hypothesize that cetuximab-conjugated AuNPs (cetuximab-AuNPs) will not only improve the cytotoxicity for cancer cells, but also introduce expression change of the related biomarkers on cancer cell surface. In this contribution, we investigated the size-dependent cytotoxicity of cetuximab-AuNPs to CRC cell line (HT-29), while also monitored the expression of cell surface biomarkers in response to treatment with cetuximab and cetuximab-AuNPs. AuNPs with the size of 60 nm showed the highest impact for cell cytotoxicity, which was tested by cell counting kit-8 (CCK-8) assay. Three cell surface biomarkers including epithelial cell adhesion molecule (EpCAM), melanoma cell adhesion molecule (MCAM), and human epidermal growth factor receptor-3 (HER-3) were found to be expressed at higher heterogeneity when cetuximab was conjugated to AuNPs. Both surface-enhanced Raman scattering/spectroscopy (SERS) and flow cytometry demonstrated the correlation of cell surface biomarkers in response to the drug treatment. We thus believe this study provides powerful potential for drug-conjugated AuNPs to enhance cancer prognosis and therapy.

Creation of Gold Nanoparticles in ZnO by Ion Implantation-DFT and Experimental Studies

Three different crystallographic orientations of the wurtzite ZnO structure (labeled as c-plane, a-plane and m-plane) were implanted with Au⁺ ions using various energies and fluences to form gold nanoparticles (GNPs). The ion implantation process was followed by annealing at 600 °C in an oxygen atmosphere to decrease the number of unwanted defects and improve luminescence properties. With regard to our previous publications, the paper provides a summary of theoretical and experimental results, i.e., both DFT and FLUX simulations, as well as experimental results from TEM, HRTEM, RBS, RBS/C, Raman spectroscopy and photoluminescence. From the results, it follows that in the ZnO structure, implanted gold atoms are located in random interstitial positions -experimentally, the amount of interstitial gold atoms increased with increasing ion implantation fluence. During ion implantation and subsequent annealing, the metal clusters and nanoparticles with sizes from 2 to 20 nm were formed. The crystal structure of the resulting gold was not cubic (confirmed by diffraction patterns), but it had a hexagonal close-packed (hcp) arrangement. The ion implantation of gold leads to the creation of Zn and O interstitial defects and extended defects with distinct character in various crystallographic cuts of ZnO, where significant O-sublattice disordering occurred in m-plane ZnO.

Beyond gold nanoparticles cytotoxicity: Potential to impair metastasis hallmarks

Gold nanoparticle (AuNP)-based systems have been extensively investigated as diagnostic and therapeutic agents due to their tunable properties and easy surface functionalization. Upon cell uptake, AuNPs present an inherent cell impairment potential based on organelle and macromolecules damage, leading to cell death. Such cytotoxicity is concentration-dependent and completely undesirable, especially if unspecific. However, under non-cytotoxic concentrations, internalized AuNPs could potentially weaken cells and act as antitumor agents. Therefore, this study aimed to investigate the antitumor effect of ultrasmall AuNPs (~3 nm) stabilized by the anionic polysaccharide gum arabic (GA-AuNPs). Other than intrinsic cytotoxicity, the focus was downregulation of cancer hallmarks of aggressive tumors, using a highly metastatic model of melanoma. We first demonstrated that GA-AuNPs showed excellent stability under biological environment. Non-cytotoxic concentrations to seven different cell lines, including tumorigenic and non-tumorigenic cells, were determined by standard 2D in vitro assays. Gold concentrations ≤ 2.4 mg L^-1 (16.5 nM AuNPs) were non-cytotoxic and therefore chosen for further analyses. Cells exposed to GA-AuNPs were uptaken by melanoma cells through endocytic processes. Next we described remarkable biological properties using non-cytotoxic concentrations of this nanomaterial. Invasion through an extracellular matrix barrier as well as 3D growth capacity (anchorage-independent colony formation and spheroids growth) were negatively affected by 2.4 mg L^-1 GA-AuNPs. Additionally, exposed spheroids showed morphological changes, suggesting that GA-AuNPs could penetrate into the preformed tumor and affect its integrity. All together these results demonstrate that side effects, such as cytotoxicity, can be avoided by choosing the right concentration, nevertheless, preserving desirable effects such as modulation of key tumor cell malignancy features.

Role of gold nanoparticles in advanced biomedical applications

Gold nanoparticles (GNPs) have generated keen interest among researchers in recent years due to their excellent physicochemical properties. In general, GNPs are biocompatible, amenable to desired functionalization, non-corroding, and exhibit size and shape dependent optical and electronic properties. These excellent properties of GNPs exhibit their tremendous potential for use in diverse biomedical applications. Herein, we have evaluated the recent advancements of GNPs to highlight their exceptional potential in the biomedical field. Special focus has been given to emerging biomedical applications including bio-imaging, site specific drug/gene delivery, nano-sensing, diagnostics, photon induced therapeutics, and theranostics. We have also elaborated on the basics, presented a historical preview, and discussed the synthesis strategies, functionalization methods, stabilization techniques, and key properties of GNPs. Lastly, we have concluded this article with key findings and unaddressed challenges. Overall, this review is a complete package to understand the importance and achievements of GNPs in the biomedical field.

Advances in Gold Nanoparticle-Based Combined Cancer Therapy

According to the global cancer observatory (GLOBOCAN), there are approximately 18 million new cancer cases per year worldwide. Cancer therapies are largely limited to surgery, radiotherapy, and chemotherapy. In radiotherapy and chemotherapy, the maximum tolerated dose is presently being used to treat cancer patients. The integrated development of innovative nanoparticle (NP) based approaches will be a key to address one of the main issues in both radiotherapy and chemotherapy: normal tissue toxicity. Among other inorganic NP systems, gold nanoparticle (GNP) based systems offer the means to further improve chemotherapy through controlled delivery of chemotherapeutics, while local radiotherapy dose can be enhanced by targeting the GNPs to the tumor. There have been over 20 nanotechnology-based therapeutic products approved for clinical use in the past two decades. Hence, the goal of this review is to understand what we have achieved so far and what else we can do to accelerate clinical use of GNP-based therapeutic platforms to minimize normal tissue toxicity while increasing the efficacy of the treatment. Nanomedicine will revolutionize future cancer treatment options and our ultimate goal should be to develop treatments that have minimum side effects, for improving the quality of life of all cancer patients.

Recent advancement of imidazolate framework (ZIF-8) based nanoformulations for synergistic tumor therapy

As a new kind of porous material, zeolitic imidazolate frameworks (ZIF-8) are built from zinc ions and 2-methylimidazolate and possess unique merits including high porosity, good structural regularity and tunability, adjustable surface functionality and intrinsic pH induced biodegradability. These advantages endow ZIF-8 with multiple functionalities and stimuli-responsive controlled release of loaded payloads by endogenous or exogenous means. In this review, we will summarize the recent advancement of ZIF-8 as nanocarriers for the loading of various molecules including chemotherapeutic drugs, photosensitizers, photothermal agents, and proteins to fabricate multifunctional nanocomposites for synergistic cancer therapy. In addition, the challenges and future developments in this area will be highlighted.

Recent progress in optical probing and manipulation of tissue: introduction

This feature issue of Biomedical Optics Express represents a cross-section of the most recent work in tissue optics, including exciting developments in tissue optical clearing, deep tissue imaging, optical elastography, nanophotonics in tissue, and therapeutic applications of light, amongst others. A collection of 33 papers provides a comprehensive overview of current research in tissue optics, much of it inspired and informed by the pioneering work of Prof. Valery Tuchin. The issue contains three invited manuscripts and several mini-reviews that we hope will benefit researchers in this exciting area.