The comparative effect of wrapping solid gold nanoparticles and hollow gold nanoparticles with doxorubicin-loaded thermosensitive liposomes for cancer thermo-chemotherapy

Plasmonic-Driven Regulation of Biomolecular Activity In Situ

Selective and remote manipulation of activity for biomolecules, including protein, DNA, and lipids, is crucial to elucidate their molecular function and to develop biomedical applications. While advances in tool development, such as optogenetics, have significantly impacted these directions, the requirement for genetic modification significantly limits their therapeutic applications. Plasmonic nanoparticle heating has brought new opportunities to the field, as hot nanoparticles are unique point heat sources at the nanoscale. In this review, we summarize fundamental engineering problems such as plasmonic heating and the resulting biomolecular responses. We highlight the biological responses and applications of manipulating biomolecules and provide perspectives for future directions in the field.

Tau- and α-synuclein-targeted gold nanoparticles: applications, opportunities, and future outlooks in the diagnosis and therapy of neurodegenerative diseases

The use of nanomaterials in medicine offers multiple opportunities to address neurodegenerative disorders such as Alzheimer's and Parkinson's disease. These diseases are a significant burden for society and the health system, affecting millions of people worldwide without sensitive and selective diagnostic methodologies or effective treatments to stop their progression. In this sense, the use of gold nanoparticles is a promising tool due to their unique properties at the nanometric level. They can be functionalized with specific molecules to selectively target pathological proteins such as Tau and α-synuclein for Alzheimer's and Parkinson's disease, respectively. Additionally, these proteins are used as diagnostic biomarkers, wherein gold nanoparticles play a key role in enhancing their signal, even at the low concentrations present in biological samples such as blood or cerebrospinal fluid, thus enabling an early and accurate diagnosis. On the other hand, gold nanoparticles act as drug delivery platforms, bringing therapeutic agents directly into the brain, improving treatment efficiency and precision, and reducing side effects in healthy tissues. However, despite the exciting potential of gold nanoparticles, it is crucial to address the challenges and issues associated with their use in the medical field before they can be widely applied in clinical settings. It is critical to ensure the safety and biocompatibility of these nanomaterials in the context of the central nervous system. Therefore, rigorous preclinical and clinical studies are needed to assess the efficacy and feasibility of these strategies in patients. Since there is scarce and sometimes contradictory literature about their use in this context, the main aim of this review is to discuss and analyze the current state-of-the-art of gold nanoparticles in relation to delivery, diagnosis, and therapy for Alzheimer's and Parkinson's disease, as well as recent research about their use in preclinical, clinical, and emerging research areas.

Development of Hollow Gold Nanoparticles for Photothermal Therapy and Their Cytotoxic Effect on a Glioma Cell Line When Combined with Copper Diethyldithiocarbamate

Gold-based nanoparticles hold promise as functional nanomedicines, including in combination with a photothermal effect for cancer therapy in conjunction with chemotherapy. Here, we synthesized hollow gold nanoparticles (HGNPs) exhibiting efficient light absorption in the near-IR (NIR) region. Several synthesis conditions were explored and provided monodisperse HGNPs approximately 95-135 nm in diameter with a light absorbance range of approximately 600-720 nm. The HGNPs were hollow and the surface had protruding structures when prepared using high concentrations of HAuCl4. The simultaneous nucleation of a sacrificial AgCl template and Au nanoparticles may affect the resulting HGNPs. Diethyldithiocarbamate (DDTC) is metabolized from disulfiram and is a repurposed drug currently attracting attention. The chelation of DDTC with copper ion (DDTC-Cu) has been investigated for treating glioma, and here we confirmed the cytotoxic effect of DDTC-Cu towards rat C6 glioma cells in vitro. HGNPs alone were biocompatible and showed little cytotoxicity, whereas a mixture of DDTC-Cu and HGNPs was cytotoxic in a dose dependent manner. The temperature of HGNPs was increased by NIR-laser irradiation. The photothermal effect on HGNPs under NIR-laser irradiation resulted in cytotoxicity towards C6 cells and was dependent on the irradiation time. Photothermal therapy by HGNPs combined and DDTC-Cu was highly effective, suggesting that this combination approach hold promise as a future glioma therapy.

α-Lipoic acid loaded hollow gold nanoparticles designed for osteoporosis treatment: preparation, characterization and in vitro evaluation

Osteoporosis is a common disease among the ageing society. Oxidative stress caused by excessive accumulation of reactive oxygen species (ROS) is the aetiology of osteoporosis. α-Lipoic acid (ALA) is an antioxidant in the body, which can eliminate excess ROS in the body and inhibits levels of oxidative stress in cells. Herein, we designed PEGylated hollow gold nanoparticles (HGNPs) loaded with ALA (mPEG@HGNPs-ALA) to remove ROS in the treatment of osteoporosis. First, mPEG@HGNPs with a particle size of ∼63 nm has been successfully synthesized. By comparing the drug loading of mPEG@HGNPs, it was concluded that the optimal mass ratio of mPEG@HGNPs (calculated by the amount of gold) to ALA was ∼1:2. ABTS antioxidant assay showed that free radical removal ability. In vitro results revealed that the preparation had good biocompatibility. At the gold concentration of 1-150 μg/mL, the cell viability of mPEG@HGNPs was more than 100%, which indicated that it could promote the proliferation of osteoblasts. What's more, mPEG@HGNPs-ALA could effectively remove the ROS caused by H₂O₂ injury and improve the cell viability. According to these results, it can be considered that mPEG@HGNPs-ALA has the potential to treat osteoporosis.

Single Pulse Nanosecond Laser-Stimulated Targeted Delivery of Anti-Cancer Drugs from Hybrid Lipid Nanoparticles Containing 5 nm Gold Nanoparticles

Encapsulating chemotherapeutic drugs like doxorubicin (DOX) inside lipid nanoparticles (LNPs) can overcome their acute, systematic toxicity. However, a precise drug release at the tumor microenvironment for improving the maximum tolerated dose and reducing side effects has yet to be well-established by implementing a safe stimuli-responsive strategy. This study proposes an integrated nanoscale perforation to trigger DOX release from hybrid plasmonic multilamellar LNPs composed of 5 nm gold (Au) NPs clustered at the internal lamellae interfaces. To promote site-specific DOX release, a single pulse irradiation strategy is developed by taking advantage of the resonant interaction between nanosecond pulsed laser radiation (527 nm) and the plasmon mode of the hybrid nanocarriers. This approach enlarges the amount of DOX in the target cells up to 11-fold compared to conventional DOX-loaded LNPs, leading to significant cancer cell death. The simulation of the pulsed laser interactions of the hybrid nanocarriers suggests a release mechanism mediated by either explosive vaporization of thin water layers adjacent to AuNP clusters or thermo-mechanical decomposition of overheated lipid layers. This simulation indicates an intact DOX integrity following irradiation since the temperature distribution is highly localized around AuNP clusters and highlights a controlled light-triggered drug delivery system.

Hybrid Nanoplatforms Comprising Organic Nanocompartments Encapsulating Inorganic Nanoparticles for Enhanced Drug Delivery and Bioimaging Applications

Organic and inorganic nanoparticles (NPs) have attracted significant attention due to their unique physico-chemical properties, which have paved the way for their application in numerous fields including diagnostics and therapy. Recently, hybrid nanomaterials consisting of organic nanocompartments (e.g., liposomes, micelles, poly (lactic-co-glycolic acid) NPs, dendrimers, or chitosan NPs) encapsulating inorganic NPs (quantum dots, or NPs made of gold, silver, silica, or magnetic materials) have been researched for usage in vivo as drug-delivery or theranostic agents. These classes of hybrid multi-particulate systems can enable or facilitate the use of inorganic NPs in biomedical applications. Notably, integration of inorganic NPs within organic nanocompartments results in improved NP stability, enhanced bioavailability, and reduced systemic toxicity. Moreover, these hybrid nanomaterials allow synergistic interactions between organic and inorganic NPs, leading to further improvements in therapeutic efficacy. Furthermore, these platforms can also serve as multifunctional agents capable of advanced bioimaging and targeted delivery of therapeutic agents, with great potential for clinical applications. By considering these advancements in the field of nanomedicine, this review aims to provide an overview of recent developments in the use of hybrid nanoparticulate systems that consist of organic nanocompartments encapsulating inorganic NPs for applications in drug delivery, bioimaging, and theranostics.

Eco-friendly chitosan-based nanostructures in diabetes mellitus therapy: Promising bioplatforms with versatile therapeutic perspectives

Nature-derived polymers, or biopolymers, are among the most employed materials for the development of nanocarriers. Chitosan (CS) is derived from the acetylation of chitin, and this biopolymer displays features such as biocompatibility, biodegradability, low toxicity, and ease of modification. CS-based nano-scale delivery systems have been demonstrated to be promising carriers for drug and gene delivery, and they can provide site-specific delivery of cargo. Owing to the high biocompatibility of CS-based nanocarriers, they can be used in the future in clinical trials. On the other hand, diabetes mellitus (DM) is a chronic disease that can develop due to a lack of insulin secretion or insulin sensitivity. Recently, CS-based nanocarriers have been extensively applied for DM therapy. Oral delivery of insulin is the most common use of CS nanoparticles in DM therapy, and they improve the pharmacological bioavailability of insulin. Moreover, CS-based nanostructures with mucoadhesive features can improve oral bioavailability of insulin. CS-based hydrogels have been developed for the sustained release of drugs and the treatment of DM complications such as wound healing. Furthermore, CS-based nanoparticles can mediate delivery of phytochemicals and other therapeutic agents in DM therapy, and they are promising compounds for the treatment of DM complications, including nephropathy, neuropathy, and cardiovascular diseases, among others. The surface modification of nanostructures with CS can improve their properties in terms of drug delivery and release, biocompatibility, and others, causing high attention to these nanocarriers in DM therapy.

Multifunctional targeted solid lipid nanoparticles for combined photothermal therapy and chemotherapy of breast cancer

Photothermal therapy has emerged as a new promising strategy for the management of cancer, either alone or combined with other therapeutics, such as chemotherapy. The use of nanoparticles for multimodal therapy can improve treatment performance and reduce drug doses and associated side effects. Here we propose the development of a novel multifunctional nanosystem based on solid lipid nanoparticles co-loaded with gold nanorods and mitoxantrone and functionalized with folic acid for dual photothermal therapy and chemotherapy of breast cancer. Nanoparticles were produced using an economically affordable method and presented suitable physicochemical properties for tumor passive accumulation. Upon Near-Infrared irradiation (808 nm, 1.7 W cm^-2, 5 min), nanoparticles could effectively mediate a temperature increase of >20 °C. Moreover, exposure to light resulted in an enhanced release of Mitoxantrone. Furthermore, nanoparticles were non-hemolytic and well tolerated by healthy cells even at high concentrations. The active targeting strategy was found to be successful, as shown by the greater accumulation of the functionalized nanoparticles in MCF-7 cells. Finally, the combined effects of chemotherapy, light-induced drug release and photothermal therapy significantly enhanced breast cancer cell death. Overall, these results demonstrate that the developed lipid nanosystem is an efficient vehicle for breast cancer multimodal therapy.

Surface engineering of hollow gold nanoparticle with mesenchymal stem cell membrane and MUC-1 aptamer for targeted theranostic application against metastatic breast cancer

Mesenchymal stem cell membrane (MSCM)-coated biomimetic doxorubicin-loaded hollow gold nanoparticles were fabricated and decorated with MUC1 aptamer in order to provide smart theranostic platform. The prepared targeted nanoscale biomimetic platform was extensively characterized and evaluated in terms of selective delivery of DOX and CT-scan imaging. The fabricated system illustrated spherical morphology with 118 nm in diameter. Doxorubicin was loaded into the hollow gold nanoparticles through physical absorption technique with encapsulation efficiency and loading content of 77%±10 and 31%±4, respectively. The in vitro release profile demonstrated that the designed platform could respond to acidic environment, pH 5.5 and release 50% of the encapsulated doxorubicin during 48 h, while 14% of the encapsulated doxorubicin was released in physiological condition, pH 7.4 up to 48 h. The in vitro cytotoxicity experiments on 4T1 as MUC1 positive cell line illustrated that the targeted formulation could significantly increase mortality at 0.468 and 0.23 µg/ml of equivalent DOX concentration compared to non-targeted formulation while this cytotoxicity was not observed in CHO as MUC1 negative cell line. Furthermore, in vivo experiments showed high tumor accumulation of the targeted formulation even 24 h after intravenous injection which induced effective tumor growth suppression against 4T1 tumor bearing mice. On the other hand, existence of hollow gold in this platform provided CT scan imaging capability of the tumor tissue in 4T1 tumor bearing mice up to 24 h post-administration. The obtained results indicated that the designed paradigm are promising and safe theranostic system for fighting against metastatic breast cancer.

Plasmonic stimulation of gold nanorods for the photothermal control of engineered living materials

Engineered living materials (ELMs) encapsulate microorganisms within polymeric matrices for biosensing, drug delivery, capturing viruses, and bioremediation. It is often desirable to control their function remotely and in real time and so the microorganisms are often genetically engineered to respond to external stimuli. Here, we combine thermogenetically engineered microorganisms with inorganic nanostructures to sensitize an ELM to near infrared light. For this, we use plasmonic gold nanorods (AuNR) that have a strong absorption maximum at 808 nm, a wavelength where human tissue is relatively transparent. These are combined with Pluronic-based hydrogel to generate a nanocomposite gel that can convert incident near infrared light into heat locally. We perform transient temperature measurements and find a photothermal conversion efficiency of 47 %. Steady-state temperature profiles from local photothermal heating are quantified using infrared photothermal imaging and correlated with measurements inside the gel to reconstruct spatial temperature profiles. Bilayer geometries are used to combine AuNR and bacteria-containing gel layers to mimic core-shell ELMs. The thermoplasmonic heating of an AuNR-containing hydrogel layer that is exposed to infrared light diffuses to the separate but connected hydrogel layer with bacteria and stimulates them to produce a fluorescent protein. By tuning the intensity of the incident light, it is possible to activate either the entire bacterial population or only a localized region.

Thermosensitive Biomimetic Hybrid Membrane Camouflaged Hollow Gold Nanoparticles for NIR-Responsive Mild-Hyperthermia Chemo-/Photothermal Combined Tumor Therapy

As an appealing biomimetic strategy for various medical applications, cell membrane coating lacks sensitive on-demand breaking capability. Herein, we incorporated thermosensitive lipid (TSL) membrane into red blood cell (RBC) and MCF-7 cancer cell (MC) hybrid membrane ([RBC-MC]M) vesicles. The [RBC-MC-TSL]M was coated onto doxorubicin (Dox)-loaded hollow gold nanoparticles to enhance chemo-/photothermal combined tumor therapy at a mild hyperthermia temperature (≤49 °C). Double-layer coating with TSL and [RBC-MC-TSL]M as the inner and outer layer, respectively, presented better antileakage and higher NIR-responsivity than single-layer coating. The Dox release ratio upon NIR laser irradiation (≤49 °C) was 74.6%, much higher than that (33.5%) without NIR laser. The nanodrug can be efficiently and specifically taken up by MCF-7 cells. In addition, the nanodrug exhibited excellent tumor-targeting property, with 4.08- and 1.12-times Dox accumulation in MCF-7 tumors compared to free Dox and [RBC-MC]M-coated counterpart, respectively. Most importantly, TSL incorporation significantly enhanced NIR-responsive antitumor efficiency, with tumor growth inhibition ratio increased from 35.1% to 48.6% after a single dose administration. Besides, the nanodrug exhibited very good biocompatibility. Camouflaging nanoparticles with the thermosensitive biomimetic hybrid membrane provides a painless and promisingly clinical-applicable approach for effective chemo-/photothermal combined mild-hyperthermia tumor therapy.

Gold-Nanoparticle Hybrid Nanostructures for Multimodal Cancer Therapy

With the urgent need for bio-nanomaterials to improve the currently available cancer treatments, gold nanoparticle (GNP) hybrid nanostructures are rapidly rising as promising multimodal candidates for cancer therapy. Gold nanoparticles (GNPs) have been hybridized with several nanocarriers, including liposomes and polymers, to achieve chemotherapy, photothermal therapy, radiotherapy, and imaging using a single composite. The GNP nanohybrids used for targeted chemotherapy can be designed to respond to external stimuli such as heat or internal stimuli such as intratumoral pH. Despite their promise for multimodal cancer therapy, there are currently no reviews summarizing the current status of GNP nanohybrid use for cancer theragnostics. Therefore, this review fulfills this gap in the literature by providing a critical analysis of the data available on the use of GNP nanohybrids for cancer treatment with a specific focus on synergistic approaches (i.e., triggered drug release, photothermal therapy, and radiotherapy). It also highlights some of the challenges that hinder the clinical translation of GNP hybrid nanostructures from bench to bedside. Future studies that could expedite the clinical progress of GNPs, as well as the future possibility of improving GNP nanohybrids for cancer theragnostics, are also summarized.

Multifunctional stimuli-responsive hybrid nanogels for cancer therapy: Current status and challenges

With cancer research shifting focus to achieving multifunctionality in cancer treatment strategies, hybrid nanogels are making a rapid rise to the spotlight as novel, multifunctional, stimuli-responsive, and biocompatible cancer therapeutic strategies. They can possess cancer cell-specific cytotoxic effects themselves, carry drugs or enzymes that can produce cytotoxic effects, improve imaging modalities, and target tumor cells over normal cells. Hybrid nanogels bring together a wide range of desirable properties for cancer treatment such as stimuli-responsiveness, efficient loading and protection of molecules such as drugs or enzymes, and effective crossing of cellular barriers among other properties. Despite their promising abilities, hybrid nanogels are still far from being used in the clinic, and their available data remains relatively limited. However, many studies can be done to facilitate this clinical transition. This review is critically summarizing and analyzing the recent information and progress on the use of hybrid nanogels particularly inorganic nanoparticle-based and organic nanoparticle-based hybrid nanogels in the field of oncology and future directions to aid in transferring those results to the clinic. This work concludes that the future of hybrid nanogels is greatly impacted by therapeutic and non-therapeutic factors. Therapeutic factors include the lack of hemocompatibility studies, acute and chronic toxicological studies, and information on agglomeration capability and extent, tumor heterogeneity, interaction with proteins in physiological fluids, endocytosis-exocytosis, and toxicity of the nanogels' breakdown products. Non-therapeutic factors include the lack of clear regulatory guidelines and standardized assays, limitations of animal models, and difficulties associated with good manufacture practices (GMP).

Stimuli-responsive liposomal nanoformulations in cancer therapy: Pre-clinical & clinical approaches

The site-specific delivery of antitumor agents is of importance for providing effective cancer suppression. Poor bioavailability of anticancer compounds and the presence of biological barriers prevent their accumulation in tumor sites. These obstacles can be overcome using liposomal nanostructures. The challenges in cancer chemotherapy and stimuli-responsive nanocarriers are first described in the current review. Then, stimuli-responsive liposomes including pH-, redox-, enzyme-, light-, thermo- and magneto-sensitive nanoparticles are discussed and their potential for delivery of anticancer drugs is emphasized. The pH- or redox-sensitive liposomes are based on internal stimulus and release drug in response to a mildly acidic pH and GSH, respectively. The pH-sensitive liposomes can mediate endosomal escape via proton sponge. The multifunctional liposomes responsive to both redox and pH have more capacity in drug release at tumor site compared to pH- or redox-sensitive alone. The magnetic field and NIR irradiation can be exploited for external stimulation of liposomes. The light-responsive liposomes release drugs when they are exposed to irradiation; thermosensitive-liposomes release drugs at a temperature of >40 °C when there is hyperthermia; magneto-responsive liposomes release drugs in presence of magnetic field. These smart nanoliposomes also mediate co-delivery of drugs and genes in synergistic cancer therapy. Due to lack of long-term toxicity of liposomes, they can be utilized in near future for treatment of cancer patients.

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.

A triple enhanced permeable gold nanoraspberry designed for positive feedback interventional therapy

Due to the unique microenvironment, nanoparticles cannot easily penetrate deeply into tumours, which decreases their therapeutic efficacy. Thus, new strategies should be developed to solve this problem and increase the efficacy of nanomedicine. In this study, gold nanoraspberries (GNRs) were constructed using ultrasmall gold nanospheres (UGNPs) with a matrix metalloproteinase (MMP)-2/9-sensitive peptide as a cross-linking agent. These UGNPs were then modified with trastuzumab (TRA) and mertansine derivatives (DM1) via the AuS bond. TRA targets the human epidermal growth factor receptor-2 (Her-2) which is overexpressed on Her-2⁺ breast cancer cells. The AuS bond in GNRs-DM1 can be replaced by the free sulfhydryl group of GSH, which could achieve GSH dependent redox responsive release of the drug. In the mouse model of Her-2⁺ breast cancer, a "positive feedback" triple enhanced penetration platform was construct to treat tumours. Firstly, near-infrared light-triggered photothermal conversion increased vascular permeability, resulting in nanoparticle penetration. Secondly, GNRs disintegrated into UGNPs in response to stimulation with MMPs. GNRs with larger particle sizes reached the tumour site through EPR effect and active targeting. Meanwhile, UGNPs with smaller particle sizes penetrated deeply into the tumour through diffusion. Thirdly, the UGNPs transformed activated cancer-associated fibroblasts to a quiescent state, which reduced intercellular pressure and promoted the penetration of the UGNPs into the interior of the tumour. In turn, an increase in the number of nanoparticles penetrating into the tumour led to a "positive feedback" loop of triple enhanced photothermal effects and further self-amplify the permeability in vivo. Interventional photothermal therapy (IPTT) was used to improve the therapeutic efficacy by reducing the laser power attenuation caused by percutaneous irradiation. The GNRs also showed excellent multimode imaging (computed tomography, photoacoustic imaging and photothermal imaging) capabilities and high anti-tumour efficacy due to efficient tumour targeting and triple enhanced deep penetration into the tumour site. Thus, these MMP-2/redox dual-responsive GNRs are promising carriers of drugs targeting human epidermal growth factor receptor 2+ breast cancer.

Gold nanostructures: synthesis, properties, and neurological applications

Recent advances in technology are expected to increase our current understanding of neuroscience. Nanotechnology and nanomaterials can alter and control neural functionality in both in vitro and in vivo experimental setups. The intersection between neuroscience and nanoscience may generate long-term neural interfaces adapted at the molecular level. Owing to their intrinsic physicochemical characteristics, gold nanostructures (GNSs) have received much attention in neuroscience, especially for combined diagnostic and therapeutic (theragnostic) purposes. GNSs have been successfully employed to stimulate and monitor neurophysiological signals. Hence, GNSs could provide a promising solution for the regeneration and recovery of neural tissue, novel neuroprotective strategies, and integrated implantable materials. This review covers the broad range of neurological applications of GNS-based materials to improve clinical diagnosis and therapy. Sub-topics include neurotoxicity, targeted delivery of therapeutics to the central nervous system (CNS), neurochemical sensing, neuromodulation, neuroimaging, neurotherapy, tissue engineering, and neural regeneration. It focuses on core concepts of GNSs in neurology, to circumvent the limitations and significant obstacles of innovative approaches in neurobiology and neurochemistry, including theragnostics. We will discuss recent advances in the use of GNSs to overcome current bottlenecks and tackle technical and conceptual challenges.

Lipid-based nanoparticles for photosensitive drug delivery systems

Background

Numerous drug delivery strategies have been studied, but many hurdles exist in drug delivery rates to the target site. Recently, researchers have attempted to remotely control the in vivo behavior of drugs with light to overcome the shortcomings of conventional drug delivery systems. Photodynamic and photothermal systems are representative strategies wherein a photosensitive material is activated in response to a specific wavelength of light.

Area covered

Photosensitive materials generally exhibit poor solubility and low biocompatibility. Additionally, their low photostability negatively affects delivery performance. A formulation of lipid-based nanoparticles containing photosensitive substances can help achieve photosensitive drug delivery with improved biocompatibility. The lipid bilayer structure, which can be assembled and disassembled by modulating the surrounding conditions (temperature, pH, etc.), can also be crucial for controlled release of drugs.

Expert opinion

To the best of our knowledge, translation research on photoresponsive nanoparticles is scarce. However, as various drugs based on lipid nanoparticles have been clinically approved, the development potential of the lipid-based photoresponsive nanoparticles seems high. Thus, the identification of valid indications and development of optimum medical devices will increase the interest in photoresponsive material-based nanoparticles.

An injectable thermosensitive hydrogel loading with theranostic nanoprobe for synergetic chemo-photothermal therapy of multidrug-resistant hepatocellular carcinoma

Multi-drug resistance (MDR) is a complicated cellular defense mechanism for tumor cells to resist chemotherapy drugs, which is also the main cause of chemotherapy failure. In this study, we used...

Nanogold-based materials in medicine: from their origins to their future

The properties of gold-based materials have been explored for centuries in several research fields, including medicine. Multiple published production methods for gold nanoparticles (AuNPs) have shown that the physicochemical and optical properties of AuNPs depend on the production method used. These different AuNP properties have allowed exploration of their usefulness in countless distinct biomedical applications over the last few years. Here we present an extensive overview of the most commonly used AuNP production methods, the resulting distinct properties of the AuNPs and the potential application of these AuNPs in diagnostic and therapeutic approaches in biomedicine.

Novel nanostructure-coupled biosensor platform for one-step high-throughput quantification of serum neutralizing antibody after COVID-19 vaccination

COVID-19 vaccination efficacy depends on serum levels of the neutralizing antibodies (NAs) specific to the receptor-binding domain of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. Therefore, a high-throughput rapid assay capable of measuring the total SARS-CoV-2 NA level is urgently needed for COVID-19 serodiagnosis, convalescent plasma therapy, vaccine development, and assessment. Here, we developed a novel nanoplasmonic immunosorbent assay (NanoPISA) platform for one-step rapid quantification of SARS-CoV-2 NAs in clinical serum samples for high-throughput evaluation of COVID-19 vaccine effectiveness. The NanoPISA platform enhanced by the use of nanoporous hollow gold nanoparticle coupling was able to detect SARS-CoV-2 NAs with a limit of detection of 0.2 pM within 15 min without washing steps. The one-step NanoPISA for SARS-CoV-2 NA detection in clinical specimens yielded good results, comparable with those obtained in the gold-standard seroneutralization test and the surrogate virus-neutralizing enzyme-linked immunosorbent assay. Collectively, the one-step NanoPISA might be a rapid and high-throughput NA-quantification platform for evaluating the effectiveness of COVID-19 vaccines.

Design and Application of Near-Infrared Nanomaterial-Liposome Hybrid Nanocarriers for Cancer Photothermal Therapy

Liposomes are attractive carriers for targeted and controlled drug delivery receiving increasing attention in cancer photothermal therapy. However, the field of creating near-infrared nanomaterial-liposome hybrid nanocarriers (NIRN-Lips) is relatively little understood. The hybrid nanocarriers combine the dual superiority of nanomaterials and liposomes, with more stable particles, enhanced photoluminescence, higher tumor permeability, better tumor-targeted drug delivery, stimulus-responsive drug release, and thus exhibiting better anti-tumor efficacy. Herein, this review covers the liposomes supported various types of near-infrared nanomaterials, including gold-based nanomaterials, carbon-based nanomaterials, and semiconductor quantum dots. Specifically, the NIRN-Lips are described in terms of their feature, synthesis, and drug-release mechanism. The design considerations of NIRN-Lips are highlighted. Further, we briefly introduced the photothermal conversion mechanism of NIRNs and the cell death mechanism induced by photothermal therapy. Subsequently, we provided a brief conclusion of NIRNs-Lips applied in cancer photothermal therapy. Finally, we discussed a synopsis of associated challenges and future perspectives for the applications of NIRN-Lips in cancer photothermal therapy.

Targeted Chemotherapy Delivery via Gold Nanoparticles: A Scoping Review of In Vivo Studies

In the field of oncology, a lot of improvements in nanotechnology creates support for better diagnosis and therapeutic opportunities, and due to their physical and chemical properties, gold nanoparticles are highly applicable. We performed a literature review on the studies engaging the usage of gold nanoparticles on murine models with a focus on the type of the carrier, the chemotherapy drug, the target tumoral tissue and outcomes. We identified fifteen studies that fulfilled our search criteria, in which we analyzed the synthesis methods, the most used chemotherapy conjugates of gold nanoparticles in experimental cancer treatment, as well as the improved impact on tumor size and system toxicity. Due to their intrinsic traits, we conclude that chemotherapy conjugates of gold nanoparticles are promising in experimental cancer treatment and may prove to be a safer and improved therapy option than current alternatives.

Red fluorescent nanoprobe based on Ag@Au nanoparticles and graphene quantum dots for H2O2 determination and living cell imaging

A sensitive and turn-on fluorescence nanoprobe based on core-shell Ag@Au nanoparticles (Ag@AuNPs) as a fluorescence receptor and red emissive graphene quantum dots (GQDs) as a donor was fabricated. They were conjugated together through π-π stacking between the GQDs and single-strand DNA modified at the Ag@AuNPs surface. The absorption spectrum of the receptor significantly overlapped with the donor emission spectrum, leading to a strong Förster resonance energy transfer (FRET) and thus a dramatic quenching. The sensing mechanism relies on fluorescence recovery following DNA cleavage by •OH produced from Fenton-like reaction between the peroxidase-like Ag nanocore and H₂O₂. The red emissive feature (Ex/Em, 520 nm/560 nm) provides low background in physiological samples. The •OH production, great spectrum overlapping, and red emission together contributes to good sensitivity and living cell imaging capability. The fluorescence assay (intensity at 560 nm) achieves a low detection limit of 0.49 μM H₂O₂ and a wide linear range from 5 to 200 μM, superior to most of the reported fluorescent probes. The RSD value for 100 μM H₂O₂ was 1.4%. The nanoprobe exhibits excellent anti-interferences and shows low cytotoxicity. The recovery of 100 μM standard H₂O₂ in a cancer cell lysate was 85.8%. Most satisfactorily, it can realize monitoring and imaging H₂O₂ in living cells. This study not only presents a sensitive H₂O₂ probe but also provides a platform for detecting other types of reactive oxygen species.

Gold nanostructures as mediators of hyperthermia therapies in breast cancer

Breast cancer is the leading cause of cancer-related deaths among women. Due to the limitations of the current therapeutics, new treatment options are needed. Hyperthermia is a promising approach to improve breast cancer therapy, particularly when combined with chemo and radiotherapy. This area has gained more attention following association with nanotechnology, with the emergence of modalities, such as photothermal therapy (PTT). PTT is a simple, minimally invasive technique that requires a near infrared (NIR) light source and a PTT agent. Gold nanostructures are excellent PTT agents as they offer biocompatibility, versatility, high photothermal conversion efficiency, imaging contrast and an easily-modified surface. In this review, we describe the molecular basis and the current clinical aspects of hyperthermia-based therapies. The emergent area of nanoparticle-induced hyperthermia will be explored, in particular gold nanostructure-mediated PTT, focusing on recent preclinical studies for breast cancer management.

Improvement of Gold Nanorods in Photothermal Therapy: Recent Progress and Perspective

Cancer is a life-threatening disease, and there is a significant need for novel technologies to treat cancer with an effective outcome and low toxicity. Photothermal therapy (PTT) is a noninvasive therapeutic tool that transports nanomaterials into tumors, absorbing light energy and converting it into heat, thus killing tumor cells. Gold nanorods (GNRs) have attracted widespread attention in recent years due to their unique optical and electronic properties and potential applications in biological imaging, molecular detection, and drug delivery, especially in the PTT of cancer and other diseases. This review summarizes the recent progress in the synthesis methods and surface functionalization of GNRs for PTT. The current major synthetic methods of GNRs and recently improved measures to reduce toxicity, increase yield, and control particle size and shape are first introduced, followed by various surface functionalization approaches to construct a controlled drug release system, increase cell uptake, and improve pharmacokinetics and tumor-targeting effect, thus enhancing the photothermal effect of killing the tumor. Finally, a brief outlook for the future development of GNRs modification and functionalization in PTT is proposed.

Synergistic Antitumor Activity of Gramicidin/Lipophilic Bismuth Nanoparticles (BisBAL NPs) on Human Cervical Tumor Cells

The objective of this study was to study the synergistic antitumor effect of lipophilic bismuth nanoparticles (BisBAL NPs) with the antibiotic solution Neo-Poly gramicidin on human cervical tumor cells. The effect of BisBAL NPs and Neo-Poly gramicidin solution on cervical cancer cell line (HeLa) was determined by the MTT cell viability assay and fluorescence microscopy. After a 24-h exposure to 0.1× Neo-Poly gramicidin HeLa cell growth decreased 94%. Fluorescence microscopy confirmed the antitumor effect cell death was higher among treated than among non-treated cells cells. Individually, gramicidin (0.04 mg/mL) inhibited HeLa tumor cell growth most (40%), and neomycin (0.04 mg/mL) least (21%). Gramicidin (0.3 mg/mL) in combination with different concentrations (1–150 μM) of BisBAL NPs had a synergistic antitumor effect against HeLa cells, reaching an < 86% tumor growth inhibition. As far as we know, we are the first to describe the antitumor activity of the antibiotic Neo-Poly gramicidin on a human cervical cancer cell line. The action mechanism of gramicidin/BisBAL NP is based on a strong damage on cell membrane and nucleus of tumor cells. A synergistic effect of gramicidin with BisBAL NPs may be useful as an alternative therapy for cervical cancer patients.

Optical properties and stability of small hollow gold nanoparticles

In the current work, small hollow Au nanoparticles (d ≈ 16 nm) with excellent thermal stability and high photo-thermal conversion efficiency, which have great potential for use in photo-thermal cancer therapy, were prepared through galvanic replacement reaction between Ag nano-templates and gold salt. The position of surface plasmon resonance (SPR) bands for these nanoparticles could be tuned by varying the amount of gold salt. The hydrophobic hollow nanostructures were made water-dispersible by being encapsulated with poly(maleic anhydride-alt-1-octadecene) - PMAO. The obtained nanostructures were stable in an aqueous solution of NaCl with concentration up to 280 mM. The hollow gold nanoparticles (HGNPs) were then heated using an 808 nm laser at different power densities, the obtained data showed that they are highly photo-thermal stable under a high power density laser up to 1.6 W cm^-2 after three circles of irradiation at 20 min per circle (20 min continuous irradiation for each circle). The facile synthesis of small size HGNPs with a plasmon peak in the near infrared range, colloidal and photo-thermal stability, and high capacity of conversion of photon energy into heat makes them a promising material for photo-thermal and imaging applications.

A DM1-doped porous gold nanoshell system for NIR accelerated redox-responsive release and triple modal imaging guided photothermal synergistic chemotherapy

Background

Although many treatments for breast cancer are available, poor tumour targeting limits the effectiveness of most approaches. Consequently, it is difficult to achieve satisfactory results with monotherapies. The lack of accurate diagnostic and monitoring methods also limit the benefits of cancer treatment. The aim of this study was to design a nanocarrier comprising porous gold nanoshells (PGNSs) co-decorated with methoxy polyethylene glycol (mPEG) and trastuzumab (Herceptin®, HER), a therapeutic monoclonal antibody that binds specifically to human epidermal receptor-2 (HER2)-overexpressing breast cancer cells. Furthermore, a derivative of the microtubule-targeting drug maytansine (DM1) was incorporated in the PGNSs.

Methods

Prepared PGNSs were coated with mPEG, DM1 and HER via electrostatic interactions and Au–S bonds to yield DM1-mPEG/HER-PGNSs. SK-BR-3 (high HER2 expression) and MCF-7 (low HER2) breast cancer cells were treated with DM1-mPEG/HER-PGNSs, and cytotoxicity was evaluated in terms of cell viability and apoptosis. The selective uptake of the coated PGNSs by cancer cells and subsequent intracellular accumulation were studied in vitro and in vivo using inductively coupled plasma mass spectrometry and fluorescence imaging. The multimodal imaging feasibility and synergistic chemo-photothermal therapeutic efficacy of the DM1-mPEG/HER-PGNSs were investigated in breast cancer tumour-bearing mice. The molecular mechanisms associated with the anti-tumour therapeutic use of the nanoparticles were also elucidated.

Result

The prepared DM1-mPEG/HER-PGNSs had a size of 78.6 nm and displayed excellent colloidal stability, photothermal conversion ability and redox-sensitive drug release. These DM1-mPEG/HER-PGNSs were taken up selectively by cancer cells in vitro and accumulated at tumour sites in vivo. Moreover, the DM1-mPEG/HER-PGNSs enhanced the performance of multimodal computed tomography (CT), photoacoustic (PA) and photothermal (PT) imaging and enabled chemo-thermal combination therapy. The therapeutic mechanism involved the induction of tumour cell apoptosis via the activation of tubulin, caspase-3 and the heat shock protein 70 pathway. M2 macrophage suppression and anti-metastatic functions were also observed.

Conclusion

The prepared DM1-mPEG/HER-PGNSs enabled nanodart-like tumour targeting, visibility by CT, PA and PT imaging in vivo and powerful tumour inhibition mediated by chemo-thermal combination therapy in vivo. In summary, these unique gold nanocarriers appear to have good potential as theranostic nanoagents that can serve both as a probe for enhanced multimodal imaging and as a novel targeted anti-tumour drug delivery system to achieve precision nanomedicine for cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00824-5.

Smart Stimuli-Responsive Liposomal Nanohybrid Systems: A Critical Review of Theranostic Behavior in Cancer

The epoch of nanotechnology has authorized novel investigation strategies in the area of drug delivery. Liposomes are attractive biomimetic nanocarriers characterized by their biocompatibility, high loading capacity, and their ability to reduce encapsulated drug toxicity. Nevertheless, various limitations including physical instability, lack of site specificity, and low targeting abilities have impeded the use of solo liposomes. Metal nanocarriers are emerging moieties that can enhance the therapeutic activity of many drugs with improved release and targeted potential, yet numerous barriers, such as colloidal instability, cellular toxicity, and poor cellular uptake, restrain their applicability in vivo. The empire of nanohybrid systems has shelled to overcome these curbs and to combine the criteria of liposomes and metal nanocarriers for successful theranostic delivery. Metallic moieties can be embedded or functionalized on the liposomal systems. The current review sheds light on different liposomal-metal nanohybrid systems that were designed as cellular bearers for therapeutic agents, delivering them to their targeted terminus to combat one of the most widely recognized diseases, cancer.

Hybrid Nanosystems for Biomedical Applications

Inorganic/organic hybrid nanosystems have been increasingly developed for their versatility and efficacy at overcoming obstacles not readily surmounted by nonhybridized counterparts. Currently, hybrid nanosystems are implemented for gene therapy, drug delivery, and phototherapy in addition to tissue regeneration, vaccines, antibacterials, biomolecule detection, imaging probes, and theranostics. Though diverse, these nanosystems can be classified according to foundational inorganic/organic components, accessory moieties, and architecture of hybridization. Within this Review, we begin by providing a historical context for the development of biomedical hybrid nanosystems before describing the properties, synthesis, and characterization of their component building blocks. Afterward, we introduce the architectures of hybridization and highlight recent biomedical nanosystem developments by area of application, emphasizing hybrids of distinctive utility and innovation. Finally, we draw attention to ongoing clinical trials before recapping our discussion of hybrid nanosystems and providing a perspective on the future of the field.

Advances in Hollow Inorganic Nanomedicines for Photothermal-Based Therapies

Nanotechnology has prompted the development of hollow inorganic nanomedicine. These medicines are now widely investigated as photothermal-based therapies for various diseases due to their high loading capacity, tuneable wavelength, relatively small size and low density. We begin this review with a brief introduction, followed by a summary of the development of imaging-guided photothermal therapy (PTT) for cancer treatment during the last three years (from 2017 to 2020). We then introduce the antibacterial effects of these medicines on some bacterial infections, in which the pathogenic bacteria can be killed by mild photothermal effects, ions and antibiotic release. Other diseases can also be treated using hollow inorganic photothermal agents. Specifically, we discuss the use of PTT for treating Alzheimer's disease, obesity and endometriosis. Finally, we share our perspectives on the current challenges and future prospects of using hollow inorganic materials in clinical PTT for various diseases.

A polyoxyethylene sorbitan oleate modified hollow gold nanoparticle system to escape macrophage phagocytosis designed for triple combination lung cancer therapy via LDL-R mediated endocytosis

Presently, a combination of chemotherapy, radiotherapy, thermotherapy, and other treatments has become a hot topic of research for the treatment of cancer, especially lung cancer. In this study, novel hollow gold nanoparticles (HGNPs) were used as drug carriers, and in order to improve the targeting ability of HGNPs to a lung tumor site, polyoxyethylene sorbitol oleate (PSO) was chosen here as a target ligand since it can be specifically recognized by the low-density lipoprotein (LDL) receptor which is usually over expressed on A549 lung cancer cells. In this way, a PSO-modified doxorubicin-loaded HGNP drug delivery system (PSO-HGNPs-DOX) was constructed and its physicochemical properties, photothermal conversion ability, and drug release of PSO-HGNPs-DOX was investigated. Further, the effects of triple combination therapy, the intracellular uptake, and the ability to escape macrophage phagocytosis of PSO-HGNPs-DOX were also studied using A549 cells in vitro. In addition, an in vivo mouse model was also used to study the targeting of PSO-HGNPs-DOX to lung cancer. PSO-HGNPs-DOX demonstrated a good triple therapeutic effect for lung cancer (A549 cell viability was only 10% at 500 μM) by LDL receptor mediated endocytosis and was able to escape macrophage phagocytosis to enhance its accumulation at the target site. Therefore, PSO-HGNPs-DOX is a novel, safe, promising, and targeted drug carrier designed for triple combination lung cancer therapy which should be further studied for such applications.

Applications of Inorganic Nanomaterials in Photothermal Therapy Based on Combinational Cancer Treatment

BACKGROUND

Cancer is one of the major causes of death and is difficult to cure using existing clinical therapies. Clinical cancer treatments [such as surgery, chemotherapy (CHT), radiotherapy (RT) and immunotherapy (IT)] are widely used but they have limited therapeutic effects and unavoidable side effects. Recently, the development of novel nanomaterials offers a platform for combinational therapy (meaning a combination of two or more therapeutic agents) which is a promising approach for cancer therapy. Recent studies have demonstrated several types of nanomaterials suitable for photothermal therapy (PTT) based on a near-infrared (NIR) light-responsive system. PTT possesses favorable properties such as being low in cost, and having high temporospatial control with minimal invasiveness. However, short NIR light penetration depth limits its functions.

METHODS

In this review, due to their promise, we focus on inorganic nanomaterials [such as hollow mesoporous silica nanoparticles (HMSNs), tungsten sulfide quantum dots (WS2QDs), and gold nanorods (AuNRs)] combining PTT with CHT, RT or IT in one treatment, aiming to provide a comprehensive understanding of PTT-based combinational cancer therapy.

RESULTS

This review found much evidence for the use of inorganic nanoparticles for PTT-based combinational cancer therapy.

CONCLUSION

Under synergistic effects, inorganic nanomaterial-based combinational treatments exhibit enhanced therapeutic effects compared to PTT, CHT, RT, IT or PDT alone and should be further investigated in the cancer field.

Mild-heat-inducible sequentially released liposomal complex remodels the tumor microenvironment and reinforces anti-breast-cancer therapy

Heat-responsive drug release helps celastrol & STS-coloaded liposome activate the cascade of TME normalization and enhances the anti-tumor efficacy.

Novel anti-HER2 peptide-conjugated theranostic nanoliposomes combining NaYF4:Yb,Er nanoparticles for NIR-activated bioimaging and chemo-photodynamic therapy against breast cancer

Herein, we reported the fabrication of novel peptide-conjugated ligand-targeted nanoliposomes (LTLs) for chemo-photodynamic therapy against HER2-positive breast cancer. The LTL core was utilized for encapsulating doxorubicin (DOX) for chemotherapy, and methylene blue (MB) attached NaYF₄:Yb,Er upconversion nanoparticles (UCNPs) for NIR-activated bioimaging and leveraging its visible emission for photoexciting MB for enhanced photodynamic therapy (PDT). The specificity of our LTLs was achieved by conjugating a newly discovered anti-HER2 peptide screened from a phage display peptide library. The high selectivity of the peptide-conjugated LTLs was confirmed by confocal imaging of SKBR-3 (HER2-positive) and MCF-7 (HER2-negative) breast cancer cell lines, illustrating its target-specific nature. The energy transfer from UCNPs to MB was verified, thus enabling the generation of reactive oxygen species upon activation with a 975 nm laser source (0.60 W cm^-2) under 5 min continuous excitation. A significant decline in the cell viability by 95% was observed using chemo-photodynamic combinational therapy, whereas for chemo-drug alone and PDT alone, the cell proliferation declined by 77% and 84%, respectively. Furthermore, we demonstrated an improved uptake of the LTLs inside a 3D model of SKBR-3 tumor spheroids, where the spheroid cell viability was suppressed by 66% after the use of combinational therapy. Thus, our results suggest great prospective use of theranostic LTLs for breast cancer management.

Injectable Silk-Vaterite Composite Hydrogels with Tunable Sustained Drug Release Capacity

Improving the efficiency of chemotherapy remains a key challenge in drug delivery. Many drug carriers have been designed to achieve multifunctional factors as part of their performance, including controlled release, dispersibility in aqueous environments, and targeting to cancer sites. However, it is difficult to optimize multiple properties simultaneously for a single carrier system. Here, synergistic carriers composed of vaterite microspheres and silk nanofiber hydrogels were developed to improve the dispersibility of vaterite spheres and the control of drug delivery without compromising the injectability or sensitivity to pH. The vaterite microspheres were dispersed homogeneously and remained stable in the silk nanofiber hydrogels. Doxorubicin (DOX) was effectively loaded on the vaterite spheres and silk nanofibers, forming synergistic silk-vaterite hydrogel delivery systems. The sustained delivery of DOX was tuned and controlled by vaterite stability and the DOX content loaded on the spheres and nanofibers. The cytotoxicity was regulated via the controlled delivery of DOX, suggesting the possibility of optimizing chemotherapeutic strategies. These silk-vaterite delivery hydrogels suggest a useful strategy for designing novel delivery systems for improved delivery and therapeutic benefits.

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

Functionalized gold nanoparticles (GNPs) with controlled geometrical and optical properties have been the subject of intense research and biomedical applications. This review summarizes recent data and topical problems in nanomedicine that are related to the use of variously sized, shaped, and structured GNPs. We focus on three topical fields in current nanomedicine: (1) use of GNP-based nanoplatforms for the targeted delivery of anticancer and antimicrobial drugs and of genes; (2) GNP-based cancer immunotherapy; and (3) combined chemo-, immuno-, and phototherapy. We present a summary of the available literature data and a short discussion of future work.

Inorganic nanomaterials for chemo/photothermal therapy: a promising horizon on effective cancer treatment

During the last few decades, nanotechnology has established many essential applications in the biomedical field and in particular for cancer therapy. Not only can nanodelivery systems address the shortcomings of conventional chemotherapy such as limited stability, non-specific biodistribution and targeting, poor water solubility, low therapeutic indices, and severe toxic side effects, but some of them can also provide simultaneous combination of therapies and diagnostics. Among the various therapies, the combination of chemo- and photothermal therapy (CT-PTT) has demonstrated synergistic therapeutic efficacies with minimal side effects in several preclinical studies. In this regard, inorganic nanostructures have been of special interest for CT-PTT, owing to their high thermal conversion efficiency, application in bio-imaging, versatility, and ease of synthesis and surface modification. In addition to being used as the first type of CT-PTT agents, they also include the most novel CT-PTT systems as the potentials of new inorganic nanomaterials are being more and more discovered. Considering the variety of inorganic nanostructures introduced for CT-PTT applications, enormous effort is needed to perform translational research on the most promising nanomaterials and to comprehensively evaluate the potentials of newly introduced ones in preclinical studies. This review provides an overview of most novel strategies used to employ inorganic nanostructures for cancer CT-PTT as well as cancer imaging and discusses current challenges and future perspectives in this area.

Gold nanoparticles for diagnosis and therapy of oncological diseases

Due to chemical stability, low toxicity, and relative simplicity of synthesis/modification techniques, gold nanoparticles (NP) enjoy a wide range of biomedical applications, including in vitro diagnostics, targeted drug delivery, contrast-enhanced radiation therapy, and photothermal therapy. The high ratio of the gold NP surface area to their volume facilitates design of complex nanoplatforms for various therapeutic and diagnostic purposes. Unique electrical and optical properties of gold NP known as surface plasmon resonance assist medical diagnosis. In this work we look at the basic methods for gold NP synthesis and modification, including the so-called green chemistry, talk about the pharmacological aspects of their application and highlight their potential as diagnostic agents. We believe that due to their unique properties, gold-based nanoplatforms for targeted drug delivery and theranostics have indisputable advantages over other nanoparticles.

PEGylated hollow gold nanoparticles for combined X-ray radiation and photothermal therapy in vitro and enhanced CT imaging in vivo

Up until now, hollow gold nanoparticles (HGNPs) with a spherical cavity have garnered much interest as theranostic agents in cancer therapy due to their high X-ray absorption and photothermal conversion ability. Herein, we describe the design of PEGylated hollow gold nanoparticles (mPEG@HGNPs) for combined X-ray radiation and photothermal therapy in vitro and enhanced computed tomography (CT) imaging in vivo using a breast tumor model. In vitro results revealed that mPEG@HGNPs could achieve a synergistic antitumor effect when irradiated by combined X-ray radiation and 808 nm near infrared laser light. Furthermore, mPEG@HGNPs exhibited a favorable tumor targeting effect and good CT contrast enhancement in both xenografted and orthotopic breast tumor models, due to the stealth effect of PEG which increased the enhanced permeability and retention (EPR) effect. These results suggest that mPEG@HGNPs may serve as multifunctional nanocomposites for cancer combination therapy and, thus, should be further studied.