Human HSP70 Promoter‐Based Prussian Blue Nanotheranostics for Thermo‐Controlled Gene Therapy and Synergistic Photothermal Ablation

Realizing precise control of the therapeutic process is crucial for maximizing efficacy and minimizing side effects, especially for strategies involving gene therapy (GT). Herein, a multifunctional Prussian blue (PB) nanotheranostic platform is first designed and then loaded with therapeutic plasmid DNA (HSP70‐p53‐GFP) for near‐infrared (NIR) light‐triggered thermo‐controlled synergistic GT/photothermal therapy (PTT). Due to the unique structure of the PB nanocubes, the resulting PB@PEI/HSP70‐p53‐GFP nanoparticles (NPs) exhibit excellent photothermal properties and pronounced tumor‐contrast performance in T₁/T₂‐weighted magnetic resonance imaging. Both in vitro and in vivo studies demonstrate that mild NIR‐laser irradiation (≈41 °C) activates the HSP70 promoter for tumor suppressor p53‐dependent apoptosis, while strong NIR‐laser irradiation (≈50 °C) induces photothermal ablation for cellular dysregulation and necrosis. Significant synergistic efficacy can be achieved by adjusting the NIR‐laser irradiation (from ≈41 to ≈50 °C), compared to using GT or PTT alone. In addition, in vitro and in vivo toxicity studies demonstrate that PB@PEI/HSP70‐p53‐GFP NPs have good biocompatibility. Therefore, this work provides a promising theranostic approach for controlling combined GT and PTT via the heat‐shock response.     

Stimuli‐Responsive Scaffold for Breast Cancer Treatment Combining Accurate Photothermal Therapy and Adipose Tissue Regeneration

Development of new therapeutic scaffolds to selectively destruct tumors under gentle conditions meanwhile promoting adipose tissue formation would be a promising strategy for clinical treatment of breast cancer. Herein, a stimuli‐responsive scaffold composed of polyacrylic acid‐g‐polylactic acid (PAA‐g‐PLLA) modified graphene oxide (GO) with a cleavable bond in between (GO‐PAA‐g‐PLLA), gambogic acid (GA), and polycaprolactone (PCL) is fabricated and then preseeded on adipose‐derived stem cells (ADSCs) for breast cancer treatment. This GO–GA‐polymer scaffold is able to simultaneously perform pH‐triggered low temperature (45 °C) photothermal therapy to selectively induce the apoptosis of tumor cells and significantly improve ADSCs growth without any photothermal damage. The low‐temperature photothermal therapy of the scaffolds can induce more than 95% of cell death for human breast cancer (MCF‐7) in vitro, which further completely inhibits tumor growth and finally eliminates tumor tissue in mice. Meanwhile, the prepared GO–GA‐polymer scaffold possesses the improved capability to stimulate the differentiation of ADSCs into adipocytes by upregulating adipo‐related gene expression, and significantly promotes new adipose tissue formation whether with or without NIR irradiation. These results successfully demonstrate that the prepared GO–GA‐polymer scaffolds with bifunctional properties will be a promising candidate for clinical cases involving both tumor treatment and tissue engineering.     

Metal Nanoparticles Acting as Light‐Activated Heating Elements within Composite Materials

The photothermal effect of metal nanoparticles embedded in polymeric materials can be used to efficiently generate local heat for in situ thermally processing within an existing material. Fluorescent probes are employed as thermal sensors to allow dynamical measurement of the amplitude and rate of temperature change within the polymer matrix. The efficacy of this technique is demonstrated in polymer nanocomposite samples with different morphological characteristics, namely nanofibrous mats and thin film samples. For similarly thick materials and both types of sample morphology, average temperature increases on the order of ≈100s °C are readily obtained with dilute nanoparticle concentrations under relatively low irradiation intensity. Thus, the in situ photothermal heating approach has great potential for controllably driving a multitude of thermal processes, such as triggering phase transitions, generating site‐specific cross‐linking, or initiating chemical reactions from within a material.     

PEGylated Micelle Nanoparticles Encapsulating a Non‐Fluorescent Near‐Infrared Organic Dye as a Safe and Highly‐Effective Photothermal Agent for In Vivo Cancer Therapy

Photothermal therapy (PTT), as a minimally invasive and highly effective cancer treatment approach, has received widespread attention in recent years. Tremendous effort has been devoted to explore various types of photothermal agents with high near‐infrared (NIR) absorbance for PTT cancer treatment. Despite many exciting progresses in the area, effective yet safe photothermal agents with good biocompatibility and biodegradability are still highly desired. In this work, a new organic PTT agent based on polyethylene glycol (PEG) coated micelle nanoparticles encapsulating a heptamethine indocyanine dye IR825 is developed, showing a strong NIR absorption band and a rather low quantum yield, for in vivo photothermal treatment of cancer. It is found that the IR825–PEG nanoparticles show ultra‐high in vivo tumor uptake after intravenous injection, and appear to be an excellent PTT agent for tumor ablation under a low‐power laser irradiation, without rendering any appreciable toxicity to the treated animals. Compared with inorganic nanomaterials and conjugated polymers being explored in PTT, the NIR‐absorbing micelle nanoparticles presented here may have the least safety concern while showing excellent treatment efficacy, and thus may be a new photothermal agent potentially useful in clinical applications.     

Tumor‐Penetrating Nanotherapeutics Loading a Near‐Infrared Probe Inhibit Growth and Metastasis of Breast Cancer

The tumor growth and metastasis is the leading reason for the high mortality of breast cancer. Herein, it is first reported a deep tumor‐penetrating photothermal nanotherapeutics loading a near‐infrared (NIR) probe for potential photothermal therapy (PTT) of tumor growth and metastasis of breast cancer. The NIR probe of 1,1‐dioctadecyl‐3,3,3,3‐tetramethylindotricarbocyanine iodide (DiR), a lipophilicfluorescent carbocyanine dye with strong light‐absorbing capability, is entrapped into the photothermal nanotherapeutics for PTT application. The DiR‐loaded photothermal nanotherapeutics (DPN) is homogeneous nanometer‐sized particles with the mean diameter of 24.5 ± 4.1 nm. Upon 808 nm laser irradiation, DPN presents superior production of thermal energy than free DiR both in vitro and in vivo. The cell proliferation and migration activities of metastatic 4T1 breast cancer cells are obviously inhibited by DPN in combination with NIR irradiation. Moreover, DPN can induce a higher accumulation in tumor and penetrate into the deep interior of tumor tissues. The in vivo PTT measurements indicate that the growth and metastasis of breast cancer are entirely inhibited by a single treatment of DPN with NIR irradiation. Therefore, the deep tumor‐penetrating DPN can provide a promising strategy for PTT of tumor progression and metastasis of breast cancer.     

Infrared‐Emitting QDs for Thermal Therapy with Real‐Time Subcutaneous Temperature Feedback

Nowadays, one of the most exciting applications of nanotechnology in biomedicine is the development of localized, noninvasive therapies for diverse diseases, such as cancer. Among them, nanoparticle‐based photothermal therapy (PTT), which destroys malignant cells by delivering heat upon optical excitation of nanoprobes injected into a living specimen, is emerging with great potential. Two main milestones that must be reached for PTT to become a viable clinical treatment are deep penetration of the triggering optical excitation and real‐time accurate temperature monitoring of the ongoing therapy, which constitutes a critical factor to minimize collateral damage. In this work, a yet unexplored capability of near‐infrared emitting semiconductor nanocrystals (quantum dots, QDs) is demonstrated. Temperature self‐monitored ­QD‐based PTT is presented for the first time using PbS/CdS/ZnS QDs emitting in the second biological window. These QDs are capable of acting, simultaneously, as photothermal agents (heaters) and high‐resolution fluorescent thermal sensors, making it possible to achieve full control over the intratumoral temperature increment during PTT. The differences observed between intratumoral and surface temperatures in this comprehensive investigation, through different irradiation conditions, highlight the need for real‐time control of the intratumoral temperature that allows for a dynamic adjustment of the treatment conditions in order to maximize the efficacy of the therapy.     

Selective Photothermal Tumor Therapy Using Nanodiamond‐Based Nanoclusters with Folic Acid

This paper describes the fabrication and evaluation of folic acid (FA)‐conjugated nanodiamond (ND) nanoclusters for selective photothermal tumor therapy. ND nanoclusters with surface carboxyl groups are aminated using ethylenediamine and conjugated with FA via carbodiimide chemistry. The temperature of an aqueous ND dispersion (10 μg mL^?1) is increased to 54 °C upon laser exposure for 5 min. FA‐ND nanoclusters are preferentially taken up by KB cells (folate receptor positive) compared to WI‐38 (folate receptor negative) cells, suggesting specificity for tumor cells that overexpress folate receptors. Cell viability tests reveal that FA‐ND nanoclusters effectively and selectively ablate KB cells upon near‐infrared (NIR) laser exposure. In addition, fluorescence microscopy images confirm that only KB cells treated with FA‐ND nanoclusters are ablated in a spot (200 μm in diameter) by NIR laser exposure. In an animal model, a large amount of FA‐ND nanoclusters is accumulated into tumor tissue, resulting in dramatically reduced tumor volume post‐NIR laser exposure as compared to ND nanoclusters.     

Carbon‐Based Photothermal Actuators

Actuators that can convert environmental stimuli into mechanical work are widely used in intelligent systems, robots, and micromechanics. To produce robust and sensitive actuators of different scales, efforts are devoted to developing effective actuating schemes and functional materials for actuator design. Carbon‐based nanomaterials have emerged as preferred candidates for different actuating systems because of their low cost, ease of processing, mechanical strength, and excellent physical/chemical properties. Especially, due to their excellent photothermal activity, which includes both optical absorption and thermal conductivities, carbon‐based materials have shown great potential for use in photothermal actuators. Herein, the recent advances in photothermal actuators based on various carbon allotropes, including graphite, carbon nanotubes, amorphous carbon, graphene and its derivatives, are reviewed. Different photothermal actuating schemes, including photothermal effect–induced expansion, desorption, phase change, surface tension gradient creation, and actuation under magnetic levitation, are summarized, and the light‐to‐heat and heat‐to‐work conversion mechanisms are discussed. Carbon‐based photothermal actuators that feature high light‐to‐work conversion efficiency, mechanical robustness, and noncontact manipulation hold great promise for future autonomous systems.     

Ultrasmall CuCo2S4 Nanocrystals: All‐in‐One Theragnosis Nanoplatform with Magnetic Resonance/Near‐Infrared Imaging for Efficiently Photothermal Therapy of Tumors

Copper‐based ternary bimetal chalcogenides have very promising potential as multifunctional theragnosis nanoplatform for photothermal treatment of tumors. However, the design and synthesis of such an effective platform remains challenging. In this study, hydrophilic CuCo₂S₄ nanocrystals (NCs) with a desirable size of ≈10 nm are synthesized by a simple one‐pot hydrothermal route. The as‐prepared ultrasmall CuCo₂S₄ NCs show: 1) intense near‐infrared absorption, which is attributed to 3d electronic transitions from the valence band to an intermediate band, as identified by density functional theory calculations; 2) high photothermal performance with a photothermal conversion efficiency up to 73.4%; and 3) capability for magnetic resonance (MR) imaging, as a result of the unpaired 3d electrons of cobalt. Finally, it is demonstrated that the CuCo₂S₄ NCs are a promising “all‐in‐one” photothermal theragnosis nanoplatform for photothermal cancer therapy under the irradiation of a 915 nm laser at a safe power density of 0.5 W cm^?2, guided by MR and infrared thermal imaging. This work further promotes the potential applications of ternary bimetal chalcogenides for photothermal theragnosis therapy.     

A Bifunctional Biomaterial with Photothermal Effect for Tumor Therapy and Bone Regeneration

Malignant bone tumor is one of the major bone diseases. The treatment of such a bone disease typically requires the removal of bone tumor and regeneration of tumor‐initiated bone defects simultaneously. To address this issue, it is required that implanted biomaterials should combine the bifunctions of both therapy and regeneration. In this work, a bifunctional graphene oxide (GO)‐modified β‐tricalcium phosphate (GO‐TCP) composite scaffold combining a high photothermal effect with significantly improved bone‐forming ability is prepared by 3D‐printing and surface‐modification strategies. The prepared GO‐TCP scaffolds exhibit excellent photothermal effects under the irradiation of 808 nm near infrared laser (NIR) even at an ultralow power density of 0.36 W cm^?2, while no photothermal effects are observed for pure β‐TCP scaffolds. The photothermal temperature of GO‐TCP scaffolds can be effectively modulated in the range of 40–90 °C by controlling the used GO concentrations, surface‐modification times, and power densities of NIR. The distinct photothermal effect of GO‐TCP scaffolds induces more than 90% of cell death for osteosarcoma cells (MG‐63) in vitro, and further effectively inhibits tumor growth in mice. Meanwhile, the prepared GO‐TCP scaffolds possess the improved capability to stimulate the osteogenic differentiation of rabbit bone mesenchymal stem cells (rBMSCs) by upregulating bone‐related gene expression, and significantly promote new bone formation in the bone defects of rabbits as compared to pure β‐TCP scaffolds. These results successfully demonstrate that the prepared GO‐TCP scaffolds have bifunctional properties of photothermal therapy and bone regeneration, which is believed to pave the way to design and fabricate novel implanting biomaterials in combination of therapy and regeneration functions.     

Integration of Self‐Lubrication and Near‐Infrared Photothermogenesis for Excellent Anti‐Icing/Deicing Performance

The economic and safety issues caused by ice accretion have become more and more serious. Except for traditional ways of anti‐icing, such as spraying agents, mechanical/thermal removal, etc., more economic approaches are urgently required. This work demonstrates the conceptual feasibility of using a self‐lubricated photothermal coating for both anti‐icing and deicing function. The coating is generally water repellent and infiltrated with hydrocarbon or perfluorocarbon oils as the lubricant to endow a liquid interface for preventing ice accumulation and minimizing the adhesion of ice on surfaces once it is formed. Fe₃O₄ nanoparticles are added to the film to afford high efficiency photothermal effect under near‐infrared irradiation for rapidly melting the accumulated ice. The conceptual strategy can be easily implemented as a facile method to fabricate analogous sprayed coatings. It represents a major advance to tackle the challenging icing issue that is normally seen as a disaster in everyday life.     

Size‐Transformable Metal–Organic Framework–Derived Nanocarbons for Localized Chemo‐Photothermal Bacterial Ablation and Wound Disinfection

Severe infectious diseases caused by pathogenic bacteria have become urgent threats to global public health. Antibacterial materials with combined chemo‐photothermal therapeutic capabilities possess distinct advantages when compared with many other antibacterial approaches. However, developing simplified and chemically tunable precursors to synthesize such antibacterial nanoagents for rapidly, safely, and synergistically combating pathogenic bacteria remains a huge challenge. Herein, metal–organic framework (MOF)‐derived nanocarbons with near‐infrared (NIR)‐responsive and size‐transformable capabilities are designed to overcome this challenge. The MOF‐derived nanocarbons with chemo‐photothermal bactericidal capabilities are first synthesized, and then coated with a thermoresponsive gel layer to obtain ON–OFF switching capability for bacterial trapping. The fabricated nanocarbons exhibit high photo‐to‐thermal conversion efficiency and fast size transformation from nanodispersions to micrometer aggregations upon NIR irradiation, thus enabling nanocarbons to generate localized massive heat and abundant Zn²⁺ ions for directly disrupting bacterial membrane and intracellular proteins. Furthermore, these nanocarbons not only exhibit a nearly 100% bactericidal ratio at very low dosage, but also possess highly efficient and safe wound disinfection activities, which are comparable to vancomycin. Overall, these proposed novel nanocarbons display robust and localized chemo‐photothermal bactericidal capability and possess great potential to be used as alternative to antibiotics for broad‐spectrum eradication of pathogenic bacteria.     

Engineering Versatile Nanoparticles for Near‐Infrared Light‐Tunable Drug Release and Photothermal Degradation of Amyloid β

Nanomedicines that inhibit/disassemble amyloid β (Aβ) aggregates in Alzheimer's disease (AD) are highly desirable yet remain challenging. Therapeutic efficacy and systemic delivery of reported molecules and nanoparticles (NPs) are hampered by various challenges, including low biocompatibility, off‐target toxicity, and lack of specificity. Herein, a versatile NP is designed by integrating high Aβ‐binding affinity, stimuli‐responsive drug release, and photothermal degradation properties for efficient disassembly of Aβ. Near‐infrared (NIR)‐absorbing conjugated polymer PDPP3T‐O14 serves as a photothermal core while thermal‐responsive polymer 1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphocholine at the outer layer as the NIR‐stimuli gatekeeper. Curcumin, an inhibitor of Aβ aggregation, is loaded into the NP with high encapsulation efficiency. The 5‐mer β‐sheet breaker peptides LPFFD (Leu‐Pro‐Phe‐Phe‐Asp) having high binding affinity toward Aβ are further anchored onto the surface of polyethylene glycol‐lipid shell for active Aβ‐targeting. The resultant NPs exhibit good Aβ‐targeting ability and obvious photothermal dissociation effect together with Aβ aggregation‐dependent fluorescence detection capability. Upon NIR laser irradiation, entrapped curcumin can be effectively released from the unconsolidated NPs to enhance the anti‐amyloid activity. In vitro studies demonstrate that the NPs dramatically lower Aβ‐induced cytotoxicity of PC12 cells, and therefore show great potential for the application in AD treatment.     

High‐Yield Synthesis of Multifunctional Tellurium Nanorods to Achieve Simultaneous Chemo‐Photothermal Combination Cancer Therapy

Tellurium (Te) is an important semiconductor material with low band‐gap energy, which has attracted considerable attention in recent years, due to its special chemical and physical properties and wide potential in electrochemistry, optoelectronics, and biological fields. This study demonstrates a facile and high‐yield synthesis strategy of Te nanorods (PTW‐TeNRs) decorated by polysaccharide–protein complex, which can achieve simultaneous chemo‐photothermal combination therapy against cancers. PTW‐TeNRs alone possess high stability under physiological conditions, potent anticancer activities through induction of reactive oxygen species overproduction, and high selectivity among tumor and normal cells. More importantly, they exhibit strong near‐infrared (NIR) absorbance and good photothermal conversion ability from NIR light to heat energy. Furthermore, in combination with NIR laser irradiation, PTW‐TeNRs exhibit excellent chemo‐photothermal efficiency and low toxicity as evidenced by highly efficient tumor ablation ability, but show no obvious histological damage to the major organs. Taken together, this study provides a valid tactic for facile synthesis of multifunctional tellurium nanorods for efficient and combinational cancer therapy.     

High‐Security Multifunctional Nano‐Bismuth‐Sphere‐Cluster Prepared from Oral Gastric Drug for CT/PA Dual‐Mode Imaging and Chemo‐Photothermal Combined Therapy In Vivo

Multifunctional nanoprobes that can be applied for real‐time monitoring or precision treatment of tumors have received wide interest among researchers. However, most of these nanoprobes are obtained through chemical synthesis, and thereby may contain toxic residues or harmful reagents. In this article, a nano‐bismuth‐sphere‐cluster (Bi) is synthesized via a one‐step method (after an irradiation with ultra‐violet) and is then applied in dual‐mode computed tomography/photoacoustic imaging. Bismuth potassium citrate granules, which is a common gastric drug that is highly safe and has a low price (<1 China Yuan/g), is used as the only raw material. The results show that the Bi cluster has good stability with sizes of about 25–55 nm, and a photothermal conversion efficiency as high as 39.67%. After being adsorbed onto doxorubicin, the Bi cluster can be used directly in animal experiments. Due to the effect of enhanced permeability and retention, the probe can easily enter tumor cells. Drug release can be controlled by a near‐infrared laser and the acidic environment of tumor cells, which indicates that the combined chemo‐photothermal therapy is achieved. This work presents a new dual‐mode bio‐imaging and combined chemo‐photothermal therapeutic nanoprobe that can be applied in theragnostics for tumors.     

NIR‐Laser‐Controlled Hydrogen‐Releasing PdH Nanohydride for Synergistic Hydrogen‐Photothermal Antibacterial and Wound‐Healing Therapies

For decades, hydrogen (H₂) gas has been recognized as an excellent antioxidant molecule that holds promise in treating many diseases like Alzheimer's, stroke, cancer, and so on. For the first time, active hydrogen is demonstrated to be highly efficient in antibacterial, antibiofilm, and wound‐healing applications, in particular when used in combination with the photothermal effect. As a proof of concept, a biocompatible hydrogen‐releasing PdH nanohydride, displaying on‐demand controlled active hydrogen release property under near‐infrared laser irradiation, is fabricated by incorporating H₂ into Pd nanocubes. The obtained PdH nanohydride combines both merits of bioactive hydrogen and photothermal effect of Pd, exhibiting excellent in vitro and in vivo antibacterial activities due to its synergistic hydrogen‐photothermal therapeutic effect. Interestingly, combinational hydrogen‐photothermal treatment is also proved to be an excellent therapeutic methodology in healing rats' wound with serious bacterial infection. Moreover, an in‐depth antibacterial mechanism study reveals that two potential pathways are involved in the synergistic hydrogen‐photothermal antibacterial effect. One is to upregulate bacterial metabolism relevant genes like dmpI, narJ, and nark, which subsequently encode more expression of oxidative metabolic enzymes to generate substantial reactive oxygen species to induce DNA damage and another is to cause severe bacterial membrane damage to release intracellular compounds like DNA.     

Near‐Infrared Light‐Absorptive Stealth Liposomes for Localized Photothermal Ablation of Tumors Combined with Chemotherapy

Although near‐infrared (NIR) light‐absorbing organic dyes have recently been proposed for photothermal ablation of tumors, their clinical applications have often been hampered by problems such as low water solubility and minimal tissue absorption. Rapid development of nanotechnology provides various novel nanostructures to address these issues. In this work, doxorubicin (DOX)‐loaded stealth liposomes are engineered through the incorporation of an NIR‐absorptive heptamethine indocyanine dye IR825 into the thermoresponsive liposomes for photothermal/chemo combined cancer therapy. It is demonstrated that the lipid nanostructure can enhance the bioavailability of water‐insoluble IR825 for efficient photothermal treatment, while delivering the anticancer drug doxorubicin to achieve simultaneous anticancer medication. The combined treatment of photothermal ablation and chemotherapy synergistically improves the overall cancer cell killing efficiency, which can be of future clinical interest.     

Photothermal Bimorph Actuators with In‐Built Cooler for Light Mills,Frequency Switches,and Soft Robots

Photothermal bimorph actuators are widely used for smart devices, which are generally operated in a room temperature environment, therefore a low temperature difference for actuation without deteriorating the performance is preferred. The strategy for the actuator is assembling a broadband‐light absorption layer for volume expansion and an additional water evaporation layer for cooling and volume shrinkage on a passive layer. The response time and temperature‐change‐normalized bending speed under NIR, white, and blue light illumination are at the same level of high performance, fast photothermal actuators based on polymer or polymer composites. The classical beam theory and finite element simulations are also conducted to understand the actuation mechanism of the actuator. A new type of light mill is designed based on a wing‐flapping mechanism and a light‐modulated frequency switch. A fast‐walking robot (with a speed of 26 mm s^?1) and a fast‐and‐strong mechanical gripper with a large weight‐lifting ratio (≈2142), respectively, are also demonstrated.     

Leaf-Structure-Inspired Through-Hole Electrode with Boosted Mass Transfer and Photothermal Effect for Oxygen Evolution Reactions

The sluggish kinetics of oxygen evolution reaction (OER) remains a bottleneck for the electrocatalytic water splitting. In addition to improving the intrinsic activity of electrocatalysts, the electrode structure and external environment also have a significant influence on catalytic performance. Inspired by photosynthesis in plant leaves, a photothermal conversion strategy is proposed via the decoration of photothermal responsive MoS₂/FeCoNiS-nanotube (MoS₂/FeCoNiS-NT) on designed through-hole porous nickel foam (PNF), defined as MoS₂/FeCoNiS-NT@PNF, to boost OER performance. The PNF facilitated bubble transport in OER by mimicking stomata structure of the leaf, and simultaneously, the MoS₂/FeCoNiS-NT increases light absorption and photothermal conversion by simulating the leaf epidermis. Benefiting from bionic structure and functional design, the MoS₂/FeCoNiS-NT@PNF electrode exhibits highly effective oxygen-evolving ability and excellent photothermal conversion capacity (surface temperature: 25 °C → 52.3 °C, AM1.5G), which increases the intrinsic activity of electrocatalysts. With the assistance of optimized electrode structure and the photothermal effect, the MoS₂/FeCoNiS-NT@PNF electrode exhibits a low overpotential of 214 mV to achieve 50 mA cm⁻². This research reveals that tuning the electrode structure can promote light absorption in the electrolyte in favor of OER performance, which can serve as an inspiration for the development of high-performance catalytic electrodes.     

Gold Nanoshell Nanomicelles for Potential Magnetic Resonance Imaging,Light‐Triggered Drug Release,and Photothermal Therapy

A novel multifunctional drug‐delivery platform is developed based on cholesteryl succinyl silane (CSS) nanomicelles loaded with doxorubicin, Fe₃O₄ magnetic nanoparticles, and gold nanoshells (CDF‐Au‐shell nanomicelles) to combine magnetic resonance (MR) imaging, magnetic‐targeted drug delivery, light‐triggered drug release, and photothermal therapy. The nanomicelles show improved drug‐encapsulation efficiency and loading level, and a good response to magnetic fields, even after the formation of the gold nanoshell. An enhancement for T₂‐weighted MR imaging is observed for the CDF‐Au‐shell nanomicelles. These nanomicelles display surface plasmon absorbance in the near‐infrared (NIR) region, thus exhibiting an NIR (808 nm)‐induced temperature elevation and an NIR light‐triggered and stepwise release behavior of doxorubicin due to the unique characteristics of the CSS nanomicelles. Photothermal cytotoxicity in vitro confirms that the CDF‐Au‐shell nanomicelles cause cell death through photothermal effects only under NIR laser irradiation. Cancer cells incubated with CDF‐Au‐shell nanomicelles show a significant decrease in cell viability only in the presence of both NIR irradiation and a magnetic field, which is attributed to the synergetic effects of the magnetic‐field‐guided drug delivery and the photothermal therapy. Therefore, such multicomponent nanomicelles can be developed as a smart and promising nanosystem that integrates multiple capabilities for effective cancer diagnosis and therapy.