Plasmonic Photothermal Therapy Research Articles

Experimental investigation of photothermal conversion and thermal conductivity of broadband absorbing gold nanoblackbodies and graphene oxide nanoparticles for plasmonic photothermal cancer therapy

The choice of nanomaterial is crucial for achieving desired thermal ablation of a tumors, considering nanoparticle dose/concentration and near-infrared (NIR) irradiation parameters during plasmonic photothermal therapy (PPTT). Most studies prioritize use of nanoparticles with high photothermal conversion efficiency (η) for PPTT without emphasizing the thermal conductivity (κ) within a solid tumor. Herein, two broadband absorbing nanoparticles, i.e., gold nanoblackbodies (AuNBs) and graphene oxide (GO) nanoparticles, are compared for η under similar NIR irradiation and nanoparticles dose. Further, the effect of photothermal conversion and κ are studied through tumor-tissue mimicking phantoms mimicking invasive ductal carcinoma embedded with nanoparticles, surrounded by normal tissue region. Under similar conditions, η is higher in AuNBs (73.2%) than GO nanoparticles (63.7%), while κ of GO nanoparticles embedded phantom (0.62 W/mK) surpasses AuNBs embedded phantom (0.59 W/mK) by 5.08%. Photothermal response through tumor-tissue mimicking phantoms shows that GO nanoparticles achieve higher temperatures within the entire tumor region than AuNBs due to their high κ, despite having lower η. This finding suggests that η is not the sole parameter, and it is the coupled effect of η and κ for the choice/suitability of a nanoparticle to attain desired temperatures throughout the tumor for PPTT.

Assessment of thermal damage for plasmonic photothermal therapy of subsurface tumors.

Plasmonic photothermal therapy (PPTT) involves the use of nanoparticles and near-infrared radiation to attain a temperature above 50°C within the tumor for its thermal damage. PPTT is largely explored for superficial tumors, and its potential to treat deeper subsurface tumors is dealt feebly, requiring the assessment of thermal damage for such tumors. In this paper, the extent of thermal damage is numerically analyzed for PPTT of invasive ductal carcinoma (IDC) situated at 3-9mm depths. The developed numerical model is validated with suitable tissue-tumor mimicking phantoms. Tumor (IDC) embedded with gold nanorods (GNRs) is subjected to broadband near-infrared radiation. The effect of various GNRs concentrations and their spatial distributions [viz. uniform distribution, intravenous delivery (peripheral distribution) and intratumoral delivery (localized distribution)] are investigated for thermal damage for subsurface tumors situated at various depths. Results show that lower GNRs concentrations lead to more uniform internal heat generation, eventually resulting in uniform temperature rise. Also, the peripheral distribution of nanoparticles provides a more uniform spatial temperature rise within the tumor. Overall, it is concluded that PPTT has potential to induce thermal damage for subsurface tumors, at depths of upto 9mm, by proper choice of nanoparticle distribution, dose/concentration and irradiation parameters based on the tumor location. Moreover, intravenous administration of nanoparticles seems a good choice for shallower tumors, while for deeper tumors, uniform distribution is required to attain the necessary thermal damage. In the future, the algorithm may be extended further, involving 3D patient-specific tumors and through mice model-based experiments.

Plasmonic Photothermal Therapy Based Synergistic Drug Release Application Through Gold Nanoparticles Coated and Embedded PLGA Nanoparticles

Plasmonic Photothermal Therapy Based Synergistic Drug Release Application Through Gold Nanoparticles Coated and Embedded PLGA Nanoparticles

Role of periodic irradiation and incident beam radius for plasmonic photothermal therapy of subsurface tumors

Plasmonic photothermal therapy (PPTT) is a potential technique to treat tumors selectively. However, during PPTT, issue of high temperature region and damage to the surrounding healthy is still need to be resolved. Also, treatment of deeper tumors non-invasively is a challenge for PPTT. In this paper, the effect of periodic irradiation and incident beam radius (relative to tumor size) for various gold nanorods (GNRs) concentrations is investigated to avoid much higher temperatures region with limiting thermal damage to the surrounding healthy tissue during PPTT of subsurface breast tumors located at various depths. Lattice Boltzmann method is used to solve Pennes’ bioheat model to compute the resulting photothermal temperatures for the subsurface tumor embedded with GNRs subjected to broadband near infrared radiation of intensity 1 W/cm2. Computation revealed that low GNRs concentration leads to uniform internal heat generation than higher GNRs concentrations. The results show that deeper tumors, due to attenuation of incident radiation, show low temperature rise than shallower tumors. For shallower tumors situated 3 mm deep, 70% irradiation period resulted in around 20 °C reduction (110 °C–90 °C) of maximum temperature than that with the continuous irradiation. Moreover, 70% beam radius (i.e., beam radius as 70% of the tumor radius) causes less thermal damage to the nearby healthy tissue than 100% beam radius (i.e., beam radius equal to the tumor radius). The thermal damage within the healthy tissue is minimized to the 1 mm in radial direction and 3 mm in axial direction for 70% beam radius with 70% irradiation period. Overall, periodic heating and changing beam radius of the incident irradiation lead to reduce high temperature and limit healthy tissue damage. Hence, discussed results are useful for selection of the irradiation parameters for PPTT of sub-surface tumors.

Monitoring of optical properties of tumors during laser plasmon photothermal therapy.

We studied grafted tumors obtained by subcutaneous implantation of kidney cancer cells into male white rats. Gold nanorods with a plasmon resonance of about 800 nm were injected intratumorally for photothermal heating. Experimental irradiation of tumors was carried out percutaneously using a near-infrared diode laser. Changes in the optical properties of the studied tissues in the spectral range 350-2200 nm under plasmonic photothermal therapy (PPT) were studied. Analysis of the observed changes in the absorption bands of water and hemoglobin made it possible to estimate the depth of thermal damage to the tumor. A significant decrease in absorption peaks was observed in the spectrum of the upper peripheral part and especially the tumor capsule. The obtained changes in the optical properties of tissues under laser irradiation can be used to optimize laboratory and clinical PPT procedures.

Surface engineered nanohybrids in plasmonic photothermal therapy for cancer: Regulatory and translational challenges.

Plasmonic materials as non-invasive and selective treatment strategies are gaining increasing attention in the healthcare sector due to their remarkable optical and electronic properties, where the interface between matter and light becomes enhanced and highly localized. Some attractive applications of plasmonic materials in healthcare include drug delivery to target specific tissues or cells, hence reducing the side effects of the drug and improving their efficacy; enhancing the contrast and resolution in bioimaging; and selectively heating and destroying the cancerous cells while parting the healthy cells. Despite such advancements in photothermal therapy for cancer treatment, some limitations are still challenging. These include poor photothermal conversion efficiency, heat resistance, less accumulation in the tumor microenvironment, poor biosafety of photothermal agents, damage to the surrounding healthy tissues, post-treatment inflammatory responses, etc. Even though the clinical application of photothermal therapy is primarily restricted due to poor tissue penetration of excitation light, enzyme therapy is hindered due to less therapeutic efficacy. Several multimodal strategies, including chemotherapy, radiotherapy, photodynamic therapy, and immunotherapy were developed to circumvent these side effects associated with plasmonic photothermal agents for effective mild-temperature photothermal therapy. It can be prophesied that the nanohybrid platform could pave the way for developing cutting-edge multifunctional precise nanomedicine via an ecologically sustainable approach towards cancer therapy. In the present review, we have highlighted the significant challenges of photothermal therapy from the laboratory to the clinical setting and their struggle to get approval from the Food and Drug Administration (FDA).

Multiphysics modeling of plasmonic photothermal therapy

Gold nanoparticle-enabled plasmonic photothermal therapy (PPTT) has garnered widespread attention in recent years as a highly targeted and non-invasive treatment for tumor. In order to accelerate its practical application in clinical. This study introduces a tumor computational model that combines the physical properties of plasmonic resonance and photothermal conversion with the biological characteristics of tumor growth and treatment response. The results indicate that 140 nm nanorods exhibit the best therapeutic performance and are significantly enhanced under the influence of collective effects. In addition, by coupling the average absorption power of the 140 nm nanorod as heat source to a micro-scale model, it is found that 42.5 °C is the ideal temperature for tumor tissue. Our computational model provides an important reference for optimizing the application of PPTT in tumor therapy, offering the potential for more effective, targeted, and less harmful tumor treatment.

Advance on fiber optic‐based biosensors for precision medicine: From diagnosis to therapy

AbstractPrecision medicine that takes individual variability into account is a new way to minimize the individual variability for precise diagnosis and to establish the certain strategies of efficient therapy. Due to miniaturization sensing area, remoting detection, and flexible operation of light, fiber optics have been successfully used to develop in vitro, wearable, and implanted biosensors, exhibiting high potential in precision medicine from the diagnosis in vitro to therapy in vivo. When modified with the recognition element, the fiber optic‐based biosensor enables the point of care testing for the detection of disease biomarkers. Meanwhile, the fiber optics packaged in a needle/catheter also monitor the medical Internet of things for the continuous assessment of human health. Moreover, the light from the cladding or leaky mode in the fiber optics excites the strong photothermal effect for therapy. The fiber optic‐based biosensor addressed the drawbacks of plasmonic photothermal therapy that limited penetration depths and non‐selectivity therapy. When integrated with a photothermal agent, the fiber optic‐based biosensors provide in situ information for the diagnosis as well as specifically and efficiently kill the tumor cells in deep tissues. In this review, we summarized the advances of fiber optic‐based biosensors in the diagnosis in vitro and therapy in vivo. The challenges and prospection of the fiber optic‐based biosensor application in precision medicine were also explored in depth.

Palladium Nanocapsules for Photothermal Therapy in the Near-Infrared II Biological Window.

Recent developments in nanomaterials with programmable optical responses and their capacity to modulate the photothermal effect induced by an extrinsic source of light have elevated plasmonic photothermal therapy (PPTT) to the status of a favored treatment for a variety of malignancies. However, the low penetration depth of near-infrared-I (NIR-I) lights and the need to expose the human body to a high laser power density in PPTT have restricted its clinical translation for cancer therapy. Most nanostructures reported to date exhibit limited performance due to (i) activity only in the NIR-I region, (ii) the use of intense laser, (iii) need of large concentration of nanomaterials, or (iv) prolonged exposure times to achieve the optimal hyperthermia state for cancer phototherapy. To overcome these shortcomings in plasmonic nanomaterials, we report a bimetallic palladium nanocapsule (Pd Ncap)─with a solid gold bead as its core and a thin, perforated palladium shell─with extinction both in the NIR-I as well as the NIR-II region for PPTT applications toward cancer therapy. The Pd Ncap demonstrated exceptional photothermal stability with a photothermal conversion efficiency of ∼49% at the NIR-II (1064 nm) wavelength region at a very low laser power density of 0.5 W/cm2. The nanocapsules were further surface-functionalized with Herceptin (Pd Ncap-Her) to target the breast cancer cell line SK-BR-3 and exploited for in vitro PPTT applications using NIR-II light. Pd Ncap-Her caused more than 98% cell death at a concentration of just 50 μg/mL and a laser power density of 0.5 W/cm2 with an output power of only 100 mW. Flow cytometric and microscopic analyses revealed that Pd Ncap-Her-induced apoptosis in the treated cancer cells during PPTT. Additionally, Pd Ncaps were found to have reactive oxygen species (ROS) scavenging ability, which can potentially reduce the damage to cells or tissues from ROS produced during PPTT. Also, Pd Ncap demonstrated excellent in vivo biocompatibility and was highly efficient in photothermally ablating tumors in mice. With a high photothermal conversion and killing efficiency at very low nanoparticle concentrations and laser power densities, the current nanostructure can operate as an effective phototherapeutic agent for the treatment of different cancers with ROS-protecting ability.

Standardization of In Vitro Studies for Plasmonic Photothermal therapy.

Lack of standardization is a systematic problem that impacts nanomedicine by challenging data comparison from different studies. Translation from preclinical to clinical stages indeed requires reproducible data that can be easily accessed and compared. In this work, we propose a series of experimental standards for in vitro plasmonic photothermal therapy (PPTT). This best practice guide covers the five main aspects of PPTT studies in vitro: nanomaterials, biological samples, pre-, during, and postirradiation characterization. We are confident that such standardization of experimental protocols and reported data will benefit the development of PPTT as a transversal therapy.

Plasmonic nanoparticle-based surface-enhanced Raman spectroscopy-guided photothermal therapy: emerging cancer theranostics.

Optical imaging modalities have emerged as a keystone in oncological research, capable of providing molecular and cellular information on cancer with the advantage of being minimally invasive toward healthy tissues. Photothermal therapy (PTT) has shown great potential, with the exceptional advantages of high specificity and noninvasiveness. Combining surface-enhanced Raman spectroscopy (SERS)-based optical imaging with PTT has shown tremendous potential in cancer theranostics (therapeutics +diagnosis). This comprehensive review article provides up-to-date information by exploring recent works focused mainly on the development of plasmonic nanoparticles for medical applications using SERS-guided PTT, including the fundamental principles behind SERS and the plasmon heating effect for PTT.

Plasmonic photothermal therapy in the near-IR region using gold nanostars.

Photothermal therapy using nanoparticles is a prominent technique for cancer treatment. The principle is to maximize the heat conversion efficiency using plasmonic nanoparticle-light interaction. Due to their unique optical characteristics derived from their anisotropic structure, gold nanostars (GNSs) have gotten significant attention in photothermal therapy. To design a proper cancer treatment, it is vital to study the thermal effect induced close to the gold nanoparticles, in the vicinity, and the cancerous tissue. A temperature-dependent 2D model based on finite element method models is commonly used to simulate near-IR tumor ablation. The bioheat equation describes the photothermal effect within the GNSs and the environment. Surface cooling and heating strategies, such as the periodical heating method and a reduced laser irradiation area, were investigated to address surface overheating problems. We also determined that the optimal laser radius depends on tumor aspect ratio and laser intensity. Our results provide guidelines to evaluate a safe and feasible temperature range, treatment time, optimal laser intensity, and laser radius to annihilate a tumor volume.

Plasmonic porous micro- and nano-materials based on Au/Ag nanostructures developed for photothermal cancer therapy: challenges in clinicalization.

Photothermal therapy (PTT) has developed in recent decades as a relatively safe method for the treatment of cancers. Recently, various species of gold and silver (Au and Ag) nanostructures have been developed and investigated to achieve PTT due to their highly localized surface plasmon resonance (LSPR) effect. Concisely, the collective oscillation of electrons on the surface of Au and Ag nanostructures upon exposure to a specific wavelength (depending on their size and shape) and further plasmonic resonance leads to the heating of the surface of these particles. Hence, porous species can be equipped with tiny plasmonic ingredients that add plasmonic properties to therapeutic cargoes. In this case, a precise review of the recent achievements is very important to figure out to what extent plasmonic photothermal therapy (PPTT) by Au/Ag-based plasmonic porous nanomedicines successfully treated cancers with satisfactory biosafety. Herein, we classify the various species of LSPR-active micro- and nano-materials. Moreover, the routes for the preparation of Ag/Au-plasmonic porous cargoes and related bench assessments are carefully reviewed. Finally, as the main aim of this study, principal requirements for the clinicalization of Ag/Au-plasmonic porous cargoes and their further challenges are discussed, which are critical for specialists in this field.

PLASMONIC PHOTOTHERMAL THERAPY IN EXPERIMENTAL ONCOLOGY: PROBLEMS AND PROSPECTS

Despite great advances in the treatment of cancer, the effectiveness of standard chemotherapy and radiation therapy for some malignant neoplasms remains insufficient. Plasmonic photothermal therapy (PPT) with plasmon resonance gold nanoparticles has been an intensively researched area in therapy in recent years [1, 2]. Successful PPT with nanoparticles for tumor treatment requires solving a number of problems associated with the potential toxicity and the bio-distribution of nanoparticles, including the development of the most efficient method of nanoparticle delivery, as well as optimization of their therapeutic protocol.

Investigation through the anticancer properties of green synthesized spinel ferrite nanoparticles in present and absent of laser photothermal effect

Plasmonic photothermal therapy (PPTT) by applying nanoparticles has attracted great attention as a new and effective adjuvant treatment for cancer in recent years. Ferromagnetic nanoparticles with good wavelength absorption in the infrared region are widely applied in the biomedicine field. In the present study, the CoFe2O4 and -ZnFe2O4 NPs were performed by applying Rutin extract, as a non-invasive and green synthesis method, for PPTT of MCF-7 breast cancer cells. Physical and structural characteristics were studied by using a Transmission electron microscope (TEM), Energy Dispersive X-Ray Analysis (EDX), Scanning electron microscope (SEM), Vibrating sample magnetometer (VSM) analysis, X-Ray Diffraction (XRD), and the Fourier-Transform Infrared (FTIR) spectroscopy. Microscopic images confirmed a spherical shape with an average size of 29 and 25 nm for biosynthesized CoFe2O4 and ZnFe2O4 nanoparticles, respectively. It is also revealed that the biosynthesized CoFe2O4 and ZnFe2O4 nanoparticles exhibit ferromagnetic and superparamagnetic behavior, with saturation magnetization of 56.2 and 6 emu/g, respectively. Therefore, these nanoparticles revealed excellent and effective magnetic characteristics as an important factor in magnetic hyperthermia therapeutic applications. The results of the MTT assay and inverted stage microscope revealed significant photothermal efficacy of green synthesized CoFe2O4 and ZnFe2O4 nanoparticles combined with laser radiation against MCF-7 cells; however, this effect is more prominent for CoFe2O4 nanoparticles. MTT investigation proved the low and acceptable toxicity of these nanoparticles for normal cells as a critical parameter for biological applications.

A Review of Alkali Tungsten Bronze Nanoparticles for Applications in Plasmonics

The optimal material for plasmonic applications is an electrical conductor with low damping losses, high chemical and thermal stability, simple low-cost synthetic methods, and a resonance frequency that can be tuned to suit a desired application. To date, plasmonic applications have predominantly relied on Au or Ag, but these materials are limited respectively by high damping losses and rapid corrosion. In the search for alternative plasmonic materials, the alkali tungsten bronzes have been identified as possible candidates, as they display many of the features of the optimal plasmonic material. In this review, we first describe the crystallography, electronic structure, synthesis methods and plasmonic behaviour of the tungsten bronzes. A range of plasmonic applications for tungsten bronze nanoparticles, including solar-control filtering, plasmonic photocatalysis and plasmonic photothermal therapy, are then discussed.

A bent fiber optic sensor based on gold nanoparticle-decorated silver film for integration of cytosensor and plasmonic photothermal therapy: A simulation study

The fiber optic surface plasmonic resonance (SPR), with the unique characteristic of miniaturized devices, high refractive index sensitivity, and intense plasmonic photothermal effect, is a promising technique for advanced biosensors in clinical medicine. Studies on the synergistic influence factors of the dual performance of refractive index sensitivity and surface heat field are benefitted for integration of cytosensor and phototherapy. Herein, a gold nanoparticle-decorated silver film (AuNPs-AgFM) was simulated as the coating to construct a bent fiber optic surface plasmonic resonance (SPR) through a Finite Element Method (FEM). Bending leads core mode to shift away from the center of curvature into the fiber cladding, which further reacted with the AgFM and AuNPs to generate the short wavelength peaks for cytosensor and long wavelength peaks for plasmonic photothermal therapy, respectively. Furthermore, the parameters of bent radius, AuNPs’ size, and thickness of AgFM were optimized considering both refractive index sensitivity and surface temperature. Under the optimal condition, the designed SPR biosensor exhibit high amplification sensitivity (AS) of − 2301.6 (1/RIU), wavelength sensitivity (WS) of 3120 (nm/RIU), and surface temperature of 54.9 ℃ under irradiation of near-infrared ray (NIR) laser. The proposed AuNPs-AgFM-based fiber optic SPR biosensor provides an alternative scheme to integrate cytosensor and phototherapy, further pushing fiber optics to clinical application.

Non-invasive and depth-free temperature monitoring using MR thermometry in plasmonic photothermal therapy using gold nanorods

This study used magnetic resonance (MR) thermometry to investigate the temperature increases and thermal transfer that occur during plasmonic photothermal therapy (PTT) with gold nanorods (GNRs). An artificial tumor phantom made of agarose gel containing GNRs was heated by irradiation with an 808 nm laser. The MR thermometry visualized the conditions: a well-localized temperature distribution with suppressed thermal diffusion that depended on laser power and irradiation time. A tumor phantom model was implanted in mice, and MR thermometry evaluated the temperature change in the presence and absence of GNRs and the thermal transfer into the surrounding tissues. That experiment showed that MR thermometry can be a useful tool for monitoring PTT. These results suggest that MR temperature measurement could help to establish ideal laser irradiation conditions in GNR-mediated PTT, and that it has great potential for visualizing local photothermal induction and evaluating therapeutic effects.

Polydopamine Coated Gold Nano Blackbodies for Tumor-Selective Spatial Thermal Damage During Plasmonic Photothermal Cancer Therapy.

Plasmonic photothermal therapy (PPTT), which involves nanoparticles and near-infrared radiation (NIR) to generate confined heat, is a potential technique for selective thermal damage of cancerous tissue. Herein, tumor-selective spatial damage characteristics during polydopamine (PDA) coated gold nano blackbodies (AuNBs) mediated PPTT is investigated through a tumor-tissue mimicking phantom. The spatial temperatures during PPTT were measured within the phantom mimicking the optical scattering of superficial invasive ductal carcinoma (injected with AuNBs) surrounded by a region without AuNBs. The phantom was irradiated using broadband NIR radiation (754-816 nm), and spatial temperatures were measured using thermocouples and an infrared thermal camera. The obtained results demonstrate that the tumor region's temperature was elevated to >50°C in about 2.5 minutes and was maintained thereafter for about 6 minutes, which is well sufficient for the thermal ablation of the tumor. While for the region surrounding the tumor, a temperature of about 40-44°C was attained, which is within safe limits for the said exposure duration. Overall, this study demonstrates that for the considered experimental parameters and tumor dimensions, heat-based thermal damage could be confined to the nanoparticle embedded tumor region while maintaining the safe temperature levels for the surrounding region, i.e., 2 mm beyond the tumor boundary.

Enhanced photothermal heating and combination therapy of gold nanoparticles on a breast cell model

Multi-drug resistance (MDR) in addition to the damage to non-malignant normal cells are the most difficult in cancer treatment. Drug delivery and Plasmonic photothermal therapy based on the use of resonant metallic nanoparticles have developed as promising techniques to destroy cancer cells selectively. In the present work, gold nanoparticles (AuNPs) were synthesized using trisodium citrate. The prepared AuNPs have a small size of 14 ± 4 nm and exhibit high stability with Zeta potential − 18 mV, AuNPs showed higher photothermal heating efficiency compared to irradiation with a 532 nm laser alone on the breast cancer cell line (MCF-7). Treatment of MCF-7 cells with 0.125 mM AuNPs coupled with laser irradiation for 6 min was found to significantly reduce (34%) the cell viability compared to 5% obtained with AuNPs in the same concentration and 26% with laser irradiation for 6 min without AuNPs. Moreover, the prepared AuNPs were used as an anticancer drug carrier for Doxorubicin (Dox), upon loading Dox to AuNPs there was a slight increase in the particle size to 16 ± 2 nm, FT-IR spectroscopic results showing the binding of Dox to AuNPs was through the –NH group. The potential cytotoxicity of the DOX@AuNPs nanocomposite was significantly increased compared to free DOX on the MCF7 cell line with a decrease in IC50. All these results suggested the potential use of AuNPs as therapeutic photothermal agents and drug carriers in cancer therapy.