Gold nanorod-encapsulated biodegradable polymeric matrix for combined photothermal and chemo-cancer therapy

Advances in stimuli-responsive gold nanorods for drug-delivery and targeted therapy systems

In recent years, the use of gold nanorods (AuNRs) has garnered considerable attention in biomedical applications due to their unique optical and physicochemical properties. They have been considered as potential tools for the advanced treatment of diseases by various stimuli such as magnetic fields, pH, temperature and light in the fields of targeted therapy, imaging and drug delivery. Their biocompatibility and tunable plasmonic properties make them a versatile platform for a range of biomedical applications. While endogenous stimuli have limited cargo delivery control at specific sites, exogenous stimuli are a more favored approach despite their circumscribed penetration depth for releasing the cargo at the specific target. Dual/multi-stimuli responsive AuNTs can be triggered by multiple stimuli for enhanced control and specificity in biomedical applications. This review provides to provide a summary of the biomedical applications of stimuli-responsive AuNRs, including their endogenous and exogenous properties, as well as their dual/multi-functionality and potential for clinical delivery. This review provides a comprehensive review on the improvement of therapeutic efficacy and the effective control of drug release with AuNRs, highlights AuNRs design strategies in recent years, discusses the advantages or challenges so far in the field of AuNRs. Finally, we have addressed the clinical translation bio-integrated nanoassemblies (CTBNs) in this field.

Emerging Progress of RNA-Based Antitumor Therapeutics

RNA-based therapeutics (e.g., mRNAs, siRNAs, microRNAs, ASOs, and saRNAs) have considerable potential for tumor treatment. The development and optimization of RNA modifications and delivery systems enable the stable and efficient delivery of RNA cargos in vivo to elicit an antitumor response. Targeted RNA-based therapeutics with multiple specificities and high efficacies are now available. In this review, we discuss progress in RNA-based antitumor therapeutics, including mRNAs, siRNAs, miRNAs, ASOs, saRNAs, RNA aptamers, and CRISPR-based gene editing. We focus on the immunogenicity, stability, translation efficiency, and delivery of RNA drugs, and summarize their optimization and the development of delivery systems. In addition, we describe the mechanisms by which RNA-based therapeutics induce antitumor responses. Furthermore, we review the merits and limitations of RNA cargos and their therapeutic potential for cancers.

Gold nanorods-loaded chitosan-based nanomedicine platform enabling an effective tumor regression in vivo

The clinical utility of 7-ethyl-10-hydroxycamptothecin (SN-38) is hampered by its low water solubility and reduced bioactivity at neutral or alkaline conditions. The rational design of an effective drug delivery system that can significantly enhance the therapeutic index of SN-38 and achieve complete tumor regression still remains a challenge. Herein, chitosan-based hybrid nanoparticles system co-loading with chemotherapeutic drug SN-38 and gold nanorods (AuNRs) was engineered for effective combinational photothermal-chemotherapy. To increase the solubility of SN-38, soluble polymeric prodrug poly (l-glutamic acid)-SN38 (l-PGA-SN38) was firstly synthesized and then complexed with chitosan to form stable nanomedicine via a mild and facile way without using any organic solvent or surfactant. Upon introducing AuNRs into chitosan-based nanomedicine by coordination interaction between the amine group of chitosan and AuNRs, the hybrid nanoparticles exhibited distinct synergistic therapeutic effect compared with single chemotherapy or photothermal treatment in vitro and in vivo. Almost complete tumor regression was achieved after 21-day treatment of the developed hybrid nanoparticles and showed no recurrence for at least 60 days.

A novel gold-polymer-antibody conjugate for targeted (radio-photothermal) treatment of HepG2 cells

Localization of the near-infrared (NIR) plasmonic nanoparticles at the tumor sites is essential for safe and efficient photothermal therapy of cancer. In this work, two biocompatible polymers: modified poly(ethylene glycol) (PEG) and branched polyethyleneimine (bPEI) were used to bind plasmonic hollow gold nanospheres (HAuNS) to the tumor-specific antibody, atezolizumab (ATZ). The photo-immunoconjugate (HAuNS-PEI-PEG-ATZ) was prepared via a simple and cost-effective procedure. The conjugate was also prepared with the radioiodinated antibody (ATZ-¹³¹I) to combine the targeted radio- and photothermal cytotoxic actions against human hepatoma (HepG2) cells. In vitro study revealed that attachment to the antibody and the use of cellular internalizing polymers enhanced the cellular localization of both gold and the radiotherapeutic Iodine-131. Compared to bare gold nanoparticles, (HAuNS-PEI-PEG-ATZ) conjugate exhibited a significantly enhanced photothermal ablation of HepG2 cells after laser irradiation (0.4 W cm^-2, 5 min). Laser irradiation of the cells treated with the radiolabeled conjugate (HAuNS-PEI-PEG-ATZ-¹³¹I) exhibited the highest cytotoxicity against HepG2 cells due to the combinatorial cytotoxic effects.

MSOT-Guided Nanotheranostics for Synergistic Mild Photothermal Therapy and Chemotherapy to Boost Necroptosis/Apoptosis

The development of nanotheranostics for precision imaging-guided regulated cell death-mediated synergistic tumor therapy is still challenging. Herein, a novel multifunctional nanotheranostic agent, iRGD-coated maleimide-poly(ethylene glycol)-poly(lactic acid/glycolic acid)-encapsulated hydrophobic gold nanocages (AuNCs) and hydrophilic epigallocatechin gallate (EGCG) (PAuE) is developed for multispectral optoacoustic tomography (MSOT)-guided photothermal therapy (PTT) and chemotherapy. The portions of necroptotic and apoptotic tumor cells were 52.9 and 5.4%, respectively, at 6 h post-incubation after the AuNC-induced mild PTT treatment, whereas they became 14.0 and 46.1% after 24 h, suggesting that the switch of the cell death pathway is a time-dependent process. Mild PTT facilitated the release of EGCG which induces the downregulation of hypoxia-inducible factor-1 (HIF-1α) expression to enhance apoptosis at a later stage, realizing a remarkable tumor growth inhibition in vivo. Moreover, RNA sequence analyses provided insights into the significant changes in genes related to the cross-talk between necroptosis and apoptosis pathways via PAuE upon laser irradiation. In addition, the biodistribution and metabolic pathways of PAuE have been successfully revealed by 3D MSOT. Taken together, this strategy of first combination of EGCG and AuNC-based photothermal agent via triggering necroptosis/apoptosis to downregulate HIF-1α expression in a tumor environment provides a new insight into anti-cancer therapy.

Next-generation engineered nanogold for multimodal cancer therapy and imaging: a clinical perspectives

Cancer is one of the significant threats to human life. Although various latest technologies are currently available to treat cancer, it still accounts for millions of death each year worldwide. Thus, creating a need for more developed and novel technologies to combat this deadly condition. Nanoparticles-based cancer therapeutics have offered a promising approach to treat cancer effectively while minimizing adverse events. Among various nanoparticles, nanogold (AuNPs) are biocompatible and have proved their efficiency in treating cancer because they can reach tumors via enhanced permeability and retention effect. The size and shape of the AuNPs are responsible for their diverse therapeutic behavior. Thus, to modulate their therapeutic values, the AuNPs can be synthesized in various shapes, such as spheres, cages, flowers, shells, prisms, rods, clusters, etc. Also, attaching AuNPs with single or multiple targeting agents can facilitate the active targeting of AuNPs to the tumor tissue. The AuNPs have been much explored for photothermal therapy (PTT) to treat cancer. In addition to PTT, AuNPs-based nanoplatforms have been investigated for combinational multimodal therapies in the last few years, including photodynamic therapy, chemotherapy, radiotherapy, immunotherapy, etc., to ablate cancer cells. Thus, the present review focuses on the recent advancements in the functionalization of AuNPs-based nanoconstructs for cancer imaging and therapy using combinatorial multimodal approaches to treat various cancers.

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

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

Emerging trends in the application of gold nanoformulations in colon cancer diagnosis and treatment

Colorectal cancer is one of the most aggressive types of cancer with about two million new cases and one million deaths in 2020. The side effects of the available chemotherapies and the possibility of developing resistance against treatment highlight the importance of developing new therapeutic options. The development in the field of nanotechnology have introduced the application of nanoparticles (NPs) as a promising approach in the diagnosis and treatments of colorectal cancer and other types of cancer. Gold nanoparticles (AuNPs) are currently one of the most studied materials as they possess unique tunable properties allowing them to play a role in colorectal cancer bioimaging, diagnosis, and therapy. The high surface-to-volume ratio of AuNPs mediates their utilization in drug delivery as well as functionalization to provide specific targeting. Moreover, depending on their physical properties (size, shape), AuNPs can be modified to fit the intended application. However, there are contradictory results around the pharmacokinetics of AuNPs including their biodistribution, clearance, and toxicity. This variation of opinions is most likely due to the development of different AuNPs that vary in shape, size, and surface chemistry, in addition to the conditions under which each research was carried out. The conflicting data represent a challenge in the clinical use of AuNPs suggesting the need to understand the toxicity, fate, and long-term exposure of AuNPs in vivo. Thus, there is an unmet need for the establishment of a publicly available data base for extensive analysis. In this review, we discuss the recent advances in AuNP applications in the treatment and diagnosis of colorectal cancer, mechanisms of action, and clinical challenges.

Synthesis and characterization of gold nanorods coated by mesoporous silica MCM-41 as a platform bioapplication in photohyperthermia

Gold nanoparticles have been widely investigated for biomedical applications due to their optical properties. These particles present the interesting feature of absorbing light when stimulated with laser radiation to generate heating. Among the possible morphologies for synthetic gold nanoparticles, gold nanorods have properties of great interest for applications in the photohyperthermia processes. Due to their morphology, gold nanorods can absorb light at longer wavelengths comprising specific regions of the electromagnetic spectrum, such as the region of the biological window, in which laser radiation has less interaction with tissues. However, these nanoparticles present limitations in biomedical applications, such as low colloidal and thermal stabilities that can be overcome by coating the gold nanorods with silica MCM-41. The silicate covering can provide greater stability for gold nanorods and allow multifunctionality in treating different diseases through photohyperthermia. This work developed a specific chemical route through seed and growth solutions to synthesize gold nanorods with controlled particle size, rod morphology, and silica covering for photohyperthermia applications. The synthesized samples were characterized through a multi-technique approach that successfully demonstrated the presence of gold nanorods inside the silica coating, presenting high stability and desirable textural and morphological characteristics for bioapplications. Furthermore, silica-coated gold nanorods exhibit high biocompatibility and great performance in generating therapeutic heating by absorbing laser radiation in the biological window range, making the system developed in this work a promising agent in photohyperthermia.

Polymer-Based Materials and Their Applications in Image-Guided Cancer Therapy

BACKGROUND

Advances in nanotechnology have enabled the combination of disease diagnosis and therapy into a single nano package that has tremendous potential for the development of new theranostic strategies. The variety of polymer-based materials has grown exponentially over the past several decades. Such materials have great potential as carriers in disease detection imaging and image monitoring and in systems for the precise delivery of drugs to specific target sites.

OBJECTIVE

In the present article, we review recent key developments in the synthesis of polymer-based materials for various medical applications and their clinical trials.

CONCLUSION

There is a growing range of multi-faceted, polymer-based materials with various functions. These functions include carriers for image contrast agents, drug delivery systems, and real-time image-guided systems for noninvasive or minimally invasive therapeutic procedures for cancer therapy.

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.

Doxorubicin-loaded gold nanorods: a multifunctional chemo-photothermal nanoplatform for cancer management

Two of the limitations associated with cancer treatment are the low efficacy and the high dose-related side effects of anticancer drugs. The purpose of the current study was to fabricate biocompatible multifunctional drug-loaded nanoscale moieties for co-therapy (chemo-photothermal therapy) with maximum efficacy and minimum side effects. Herein, we report in vitro anticancerous effects of doxorubicin (DOX) loaded on gold nanorods coated with the polyelectrolyte poly(sodium-4-styrenesulfonate) (PSS-GNRs) with and without NIR laser (808 nm, power density = 1.5 W/cm2 for 2 min) irradiation. The drug-loading capacity of PSS-GNRs was about 76% with a drug loading content of 3.2 mg DOX/mL. The cumulative DOX release significantly increased after laser exposure compared to non-irradiated samples (p < 0.05). The zeta potential values of GNRs, PSS-GNRs and DOX-PSS-GNRs were measured as 42 ± 0.1 mV, -40 ± 0.3 mV and 39.3 ± 0.6 mV, respectively. PSS-GNRs nanocomplexes were found to be biocompatible and showed higher photothermal stability. The DOX-conjugated nanocomplexes with NIR laser irradiation appear more efficient in cell inhibition (93%) than those without laser exposure (65%) and doxorubicin alone (84%). The IC50 values of PSS-GNRs-DOX and PSS-GNRs-DOX were measured as 7.99 and 3.12 µg/mL, respectively, with laser irradiation. Thus, a combinatorial approach based on chemotherapy and photothermal strategies appears to be a promising platform in cancer management.

Cytotoxicity of targeted PLGA nanoparticles: a systematic review

Recent advances in nanotechnology have contributed tremendously to the development and revolutionizing of drug delivery systems in the field of nanomedicine. In particular, targeting nanoparticles based on biodegradable poly(lactic-co-glycolic acid) (PLGA) polymers have gained much interest. However, PLGA nanoparticles remain of concern for their effectiveness against cancer cells and their toxicity to normal cells. The aim of this systematic review is to identify a promising targeting PLGA nanoformulation based on the comparison study of their cytotoxicity potency in different cell lines. A literature search was conducted through the databases of Google Scholar, PubMed, ScienceDirect, Scopus and SpringerLink. The sources studied were published between 2009 and 2019, and a variety of keywords were utilized. In total, 81 manuscripts that met the inclusion and exclusion criteria were selected for analysis based on their cytotoxicity, size, zeta potential, year of publication, type of ligand, active compounds and cell line used. The half maximal inhibitory concentration (IC50) for cytotoxicity was the main measurement in this data extraction, and the SI units were standardized to μg mL-1 for a better view of comparison. This systematic review also identified that cytotoxicity potency was inversely proportional to nanoparticle size. The PLGA nanoparticles predominantly exhibited a size of less than 300 nm and absolute zeta potential ∼20 mV. In conclusion, more comprehensive and critical appraisals of pharmacokinetic, pharmacokinetic, toxicokinetic, in vivo and in vitro tests are required for the investigation of the full value of targeting PLGA nanoparticles for cancer treatment.

Gold Nanoparticles: A New Golden Era in Oncology?

In recent years, the spectrum of possible applications of gold in diagnostics and therapeutic approaches in clinical practice has changed significantly, becoming surprisingly broad. Nowadays, gold-based therapeutic agents are used in the therapy of multiple human diseases, ranging from degenerative to infectious diseases and, in particular, to cancer. At the basis of these performances of gold, there is the development of new gold-based nanoparticles, characterized by a promising risk/benefit ratio that favors their introduction in clinical trials. Gold nanoparticles appear as attractive elements in nanomedicine, a branch of modern clinical medicine, which combines high selectivity in targeting tumor cells and low toxicity. Thanks to these peculiar characteristics, gold nanoparticles appear as the starting point for the development of new gold-based therapeutic strategies in oncology. Here, the new gold-based therapeutic agents developed in recent years are described, with particular emphasis on the possible applications in clinical practice as anticancer agents, with the aim that their application will give rise to a new golden age in oncology and a breakthrough in the fight against cancer.

Stem Cell-Based Delivery of Gold/Chlorin e6 Nanocomplexes for Combined Photothermal and Photodynamic Therapy

Combining photothermal and photodynamic modalities has shown encouraging therapeutic efficacy against various malignant cancers. Developing a delivery method for targeting and penetrating tumors is still a major focus for advancing this therapeutic approach. Herein, we report a novel strategy involving the utilization of stem cells as a live carrier to codeliver photothermal and photodynamic agents for cancer therapy. To this end, a novel gold nanorod (AuNR)-PEG-PEI (APP)/chlorin e6 (Ce6)-loaded adipose-derived stem cell (ADSC) system is proposed in which AuNRs and Ce6 act as the photothermal and photodynamic agents, respectively. To integrate with stem cells, the APP/Ce6 nanocomplexes exhibit advantages of low drug leakage, low cytotoxicity, efficient cellular uptake, and redox-responsive release. After loading of APP/Ce6 nanocomplexes, the ADSCs still maintained good tumor tropism and were capable of penetrating into the tumor spheroids. The photothermal effect induced by exposure to near-infrared light irradiation at 808 nm promoted the release of Ce6 from the stem cells into the surroundings and hence increased its availability to treat cancer cells. APP/Ce6-loaded ADSCs exerted effective dose-dependent in vitro anticancer activities via anticipated photothermal and photodynamic effects. In a murine CT26 colon cancer model, APP/Ce6 delivered by ADSCs resulted in superior tumor suppression compared to other delivery strategies. It was also noted that in vivo applications of APP/Ce6-loaded ADSCs did not induce noticeable detrimental effects on normal tissues/organs.

Multifunctional Nanoparticles Encapsulating Astragalus Polysaccharide and Gold Nanorods in Combination with Focused Ultrasound for the Treatment of Breast Cancer

Purpose

Focused ultrasound (FUS) is a noninvasive method to produce thermal and mechanical destruction along with an immune-stimulatory effect against cancer. However, FUS ablation alone appears insufficient to generate consistent antitumor immunity. In this study, a multifunctional nanoparticle was designed to boost FUS-induced immune effects and achieve systemic, long-lasting antitumor immunity, along with imaging and thermal enhancement.

Materials and Methods

PEGylated PLGA nanoparticles encapsulating astragalus polysaccharides (APS) and gold nanorods (AuNRs) were constructed by a simple double emulsion method, characterized, and tested for cytotoxicity. The abilities of PA imaging and thermal-synergetic ablation efficiency were analyzed in vitro and in vivo. The immune-synergistic effect on dendritic cell (DC) differentiation in vitro and the immune response in vivo were also evaluated.

Results

The obtained APS/AuNR/PLGA-PEG nanoparticles have an average diameter of 255.00±0.1717 nm and an APS-loading efficiency of 54.89±2.07%, demonstrating their PA imaging capability and high biocompatibility both in vitro and in vivo. In addition, the as-prepared nanoparticles achieved a higher necrosis cell rate and induced apoptosis rate in an in vitro cell suspension assay, greater necrosis area and decreased energy efficiency factor (EEF) in an in vivo rabbit liver assay, and remarkable thermal-synergic performance. In particular, the nanoparticles upregulated the expression of MHC-II, CD80 and CD86 on cocultured DCs in vitro, followed by declining phagocytic function and enhanced interleukin (IL)-12 and interferon (INF)-γ production. Furthermore, they boosted the production of tumor necrosis factor (TNF)-α, IFN-γ, IL-4, IL-10, and IgG1 (P< 0.001) but not IgG2a. Immune promotion peaked on day 3 after FUS in vivo.

Conclusion

The multifunctional APS/AuNR/PLGA-PEG nanoparticles can serve as an excellent synergistic agent for FUS therapy, facilitating real-time imaging, promoting thermal ablation effects, and boosting FUS-induced immune effects, which have the potential to be used for further clinical FUS treatment.

Gold nanorod-loaded (PLGA-PEG) nanocapsules as near-infrared controlled release model of anticancer therapeutics

Despite of high in vitro anticancer efficacy of many chemotherapeutics, their in vivo use is limited due to lack of biocompatibility and tumor targeting. Near-infrared (NIR) photothermally induced phase transition of PLGA-PEG regime was utilized for developing highly efficient photoresponsive drug delivery systems. Co-encapsulation of plasmonic gold nanorods (GNRs), as NIR-trigger, with the novel and highly efficient anticancer drug N'-(2-Methoxybenzylidene)-3-methyl-1-phenyl-H-Thieno[2,3-c]Pyrazole-5-Carbohyd-razide (MTPC) produced NIR-responsive biodegradable polymeric (PLGA-b-PEG) nanocapsules. This remotely controllable drug release significantly enhanced both biodistribution and pharmacokinetics of the hydrophobic drug. Intravenous (IV) injection of the prepared nanocapsules (MTPC/GNRs@PLGA-PEG) to tumor-bearing mice followed by extracorporeal exposure of the tumor to NIR light resulted in highly selective drug accumulation at the tumor sites. In vivo biodistribution and pharmacokinetics utilizing iodine-131 drug-radiolabelling technique revealed a maximum target to non-target ratio (T/NT) of 5.8, 4 h post-injection with maximum drug level in the tumor (6.3 ± 0.6% of the injected dose). Graphical abstract.

A Review on Cancer Therapy Based on the Photothermal Effect of Gold Nanorod

Background:

Cancer causes millions of deaths and huge economic losses every year. The currently practiced methods for cancer therapy have many defects, such as side effects, low curate rate, and discomfort for patients.

Objective:

Herein, we summarize the applications of gold nanorods (AuNRs) in cancer therapy based on their photothermal effect-the conversion of light into local heat under irradiation.

Methods:

The recent advances in the synthesis and regulation of AuNRs, and facile surface functionalization further facilitate their use in cancer treatment. For cancer therapy, AuNRs need to be modified or coated with biocompatible molecules (e.g. polyethylene glycol) and materials (e.g. silicon) to reduce the cytotoxicity and increase their biocompatibility, stability, and retention time in the bloodstream. The accumulation of AuNRs in cancerous cells and tissues is due to the high leakage in tumors or the specific interaction between the cell surface and functional molecules on AuNRs such as antibodies, aptamers, and receptors.

Results:

AuNRs are employed not only as therapeutics to ablate tumors solely based on the heat produced under laser that could denature protein and activate the apoptotic pathway, but also as synergistic therapies combined with photodynamic therapy, chemotherapy, and gene therapy to kill cancer more efficiently. More importantly, other materials like TiO2, graphene oxide, and silicon, etc. are incorporated on the AuNR surface for multimodal cancer treatment with high drug loadings and improved cancer-killing efficiency. To highlight their applications in cancer treatment, examples of therapeutic effects both in vitro and in vivo are presented.

Conclusion:

AuNRs have potential applications for clinical cancer therapy.

Poly-amino acids coated gold nanorod and doxorubicin for synergistic photodynamic therapy and chemotherapy in ovarian cancer cells

In this work, we have successfully designed and formulated a doxorubicin-loaded polypeptide-based multilayer assembled gold nanorod (DH-GNR). We have hypothesized that near-infrared (NIR) laser irradiation of DH-GNR will combine the benefits of chemotherapy and photothermal therapy. The GNR was surface functionalized with poly-glutamic acid (PGA) and poly-l-Lysine (PLL) with a final layer of hyaluronic acid (HA) that could also serve as a targeting ligand toward the overexpressed CD44 receptors in ovarian cancer cells. The zigzag ζ potential of nanoparticle is a proof of successful assembly of alternative polymers on the GNR surface. NIR irradiation exhibited a burst release of drug in pH 7.4 and pH 5.0 buffer conditions. The combination of doxorubicin (DOX)-based chemotherapy and GNR-based photothermal therapy exhibited a synergistic effect in killing the SKOV3 cancer cells. DH-GNR(+NIR) induced a 82.5% apoptosis (combined early and late apoptosis) compared with only 35.2 and 38.5% for DOX or DH-GNR(-NIR) treated cell group. Results clearly suggest that the excessive reactive oxygen species (ROS) generation in DH-GNR (+NIR) might be responsible for the cell apoptosis and cell death. The promising anticancer effect of DH-GNR will be of great potential in the treatment of ovarian cancers and worth further development for treating other malignant tumors.

Engineering of Porous Silica Coated Gold Nanorods by Surface-Protected Etching and Their Applications in Drug Loading and Combined Cancer Therapy

Core-shell nanostructures, specifically gold nanorods coated with porous silica (GNR@p-SiO₂), were successfully fabricated by surface-protected etching. The nanostructures, photothermal effects, drug loading and drug release behaviors, cellular uptake, and combined chemo-photothermal therapy were investigated. The results showed that the as-prepared GNR@p-SiO₂ had a uniform porous silica outer layer. Etching process could be modulated by adjusting the etching time, concentrations of etching agents, and concentrations of protective agents. With doxorubicin (DOX) as the model drug, the drug loading capacity reached 18.9%, which was dependent on the DOX concentrations. The drug release profiles were dual stimulus-responsive to pH and laser irradiation. In addition, the GNR@p-SiO₂ nanoparticles were biocompatible and effectively internalized by cancer cells. Compared with chemotherapy or photothermal therapy administered individually, combined chemo-photothermal therapy using GNR@p-SiO₂ exhibited higher efficiency in killing cancer cells both in vitro and in vivo. Therefore, surface-protected etching is a powerful method for preparing core-shell nanostructures capped with mesoporous silica for combined cancer chemo-photothermal therapy.