Multiple-mRNA-controlled and heat-driven drug release from gold nanocages in targeted chemo-photothermal therapy for tumors

Multifunctional drug delivery systems enabling effective drug delivery and comprehensive treatment are critical to successful cancer treatment. Overcoming nonspecific release and off-target effects remains challenging in precise drug delivery. Here, we design triple-interlocked drug delivery systems to perform specific cancer cell recognition, controlled drug release and effective comprehensive therapy. Gold nanocages (AuNCs) comprise a novel class of nanostructures possessing hollow interiors and porous walls. AuNCs are employed as a drug carrier and photothermal transducer due to their unique structure and photothermal properties. A smart triple-interlocked I-type DNA nanostructure is modified on the surface of the AuNCs, and molecules of the anticancer drug doxorubicin (DOX) are loaded as molecular cargo and blocked. The triple-interlocked nanostructure can be unlocked by binding with three types of tumor-related mRNAs, which act as “keys” to the triple locks, sequentially, which leads to precise drug release. Additionally, fluorescence-imaging-oriented chemical–photothermal synergistic treatment is achieved under illumination with infrared light. This drug delivery system, which combines the advantages of AuNCs and interlocked I-type DNA, successfully demonstrates effective and precise imaging, drug release and photothermal therapy. This multifunctional triple-interlocked drug delivery system could be used as a potential carrier for effective cancer-targeting comprehensive chemotherapy and photothermal therapy treatments.

Schematic illustration of the multiple-mRNA-controlled and heat-driven drug release from gold nanocages.     

The video-rate imaging of sub-10 nm plasmonic nanoparticles in a cellular medium free of background scattering

Plasmonic nanoparticles (e.g., gold, silver) have attracted much attention for biological sensing and imaging as promising nanoprobes. Practical biomedical applications demand small gold nanoparticles (Au NPs) with a comparable size to quantum dots and fluorescent proteins. Very small nanoparticles with a size below the Rayleigh limit (usually <30–40 nm) are hard to see by light scattering using a dark-field microscope, especially within a cellular medium. A photothermal microscope is able to detect very small nanoparticles, down to a few nanometers, but the imaging speed is usually too slow (minutes to hours) to image living cell processes. Here an absorption modulated scattering microscopy (AMSM) method is presented, which allows for the imaging of sub-10 nm Au NPs within a cellular medium. The unique physical mechanism of AMSM offers the remarkable ability to remove the light scattering background of the cellular component. In addition to having a sensitivity comparable to that of photothermal microscopy, AMSM has a much higher imaging speed, close to the video rate (20 fps), which allows for the dynamic tracking of small nanoparticles in living cells. This AMSM method might be a valuable tool for living cell imaging, using sub-10 nm Au NPs as biological probes, and thereby unlocking many new applications, such as single molecule labeling and the dynamic tracking of molecular interactions.

An absorption modulated scattering microscopy technique that allows for the imaging of sub-10 nm gold nanoparticles within a cellular scattering medium is presented.     

Controlled-release system mediated by a retro Diels-Alder reaction induced by the photothermal effect of gold nanorods

Controlled-release systems that respond to external stimuli have received great interest for use in medical treatments such as for drug delivery to specific sites. Gold nanorods have an absorption band at the near-infrared region and convert the absorbed light energy into heat, which is known as a "photothermal effect". Therefore, gold nanorods are expected to act not only as an on-demand thermal converter for photothermal therapy but also as a controller of a drug-release system capable of responding to the near-infrared light irradiation. In this study, to construct a controlled-release system that responds to near-infrared light irradiation, we modified gold nanorods with polyethylene glycol (PEG) through Diels-Alder cycloadducts. When the modified gold nanorods were irradiated by near-infrared light, the PEG chains were released from the gold nanorods because of the retro Diels-Alder reaction induced by the photothermal effect. As a result of the PEG release, the gold nanorods formed aggregates. This type of controlled-release system coupled with the aggregate formation of the gold nanorods triggered by near-infrared light could be expanded to applications of gold nanorods in medical fields such as drug and photothermal therapy.     

Doxorubicin Loaded Chitosan–W18O49 Hybrid Nanoparticles for Combined Photothermal–Chemotherapy

Combined treatment is more effective than single treatment against most forms of cancer. In this work, doxorubicin loaded chitosan–W₁₈O₄₉ nanoparticles combined with the photothermal therapy and chemotherapy are fabricated through the electrostatic interaction between positively charged chitosan and negatively charged W₁₈O₄₉ nanoparticles. The in vitro and in vivo behaviors of these nanoparticles are examined by dynamic light scattering, transmission electron microscopy, cytotoxicity, near‐infrared fluorescence imaging, and tumor growth inhibition experiment. These nanoparticles have a mean size around 110 nm and show a pH sensitive drug release behavior. After irradiation by the 980 nm laser, these nanoparticles show more pronounced cytotoxicity against HeLa cells than that of free doxorubicin or photothermal therapy alone. The in vivo experiments confirm that their antitumor ability is significantly improved, resulting in superior efficiency in impeding tumor growth and extension of the lifetime of mice.

     

Luminescent Ru(bpy)3 2+-doped silica nanoparticles for imaging of intracellular temperature

Silica nanoparticles doped with the luminescent temperature probe Ru(bpy)₃ ²⁺ were prepared by a modified Stöber method and are shown to enable optical sensing of intracellular temperatures. Based on the regrowth of silica nanoseeds, the ruthenium probe was easily incorporated and then covered with a shell of pure silica. The resulting nanothermometers were immune to the quenching by oxygen owing to the outer silica layer. The nanoparticles were further coated with poly-L-lysine in order to reduce cytotoxicity and to warrant cellular uptake. The luminescence of these nanosensors is rather sensitive to temperature in the physiological range (25–45 °C), with a decrease of ?1.26 % in intensity per °C increase in temperature. The nanosensors were internalized into living cells of a hepatocellular carcinoma cell line along with gold nanorods. These display longitudinal surface plasmon resonance absorption at ~808 nm that causes a local rise in temperature. The microscopically captured luminescence intensity of the nanosensors after 808 nm irradiation of the gold nanorods decayed with increasing temperature, thereby indicating successful imaging of temperature.

Popcorn‐Shaped Magnetic Core–Plasmonic Shell Multifunctional Nanoparticles for the Targeted Magnetic Separation and Enrichment,Label‐Free SERS Imaging,and Photothermal Destruction of Multidrug‐Resistant Bacteria

Over the last few years, one of the most important and complex problems facing our society is treating infectious diseases caused by multidrug‐resistant bacteria (MDRB), by using current market‐existing antibiotics. Driven by this need, we report for the first time the development of the multifunctional popcorn‐shaped iron magnetic core–gold plasmonic shell nanotechnology‐driven approach for targeted magnetic separation and enrichment, label‐free surface‐enhanced Raman spectroscopy (SERS) detection, and the selective photothermal destruction of MDR Salmonella DT104. Due to the presence of the “lightning‐rod effect”, the core–shell popcorn‐shaped gold‐nanoparticle tips provided a huge field of SERS enhancement. The experimental data show that the M3038 antibody‐conjugated nanoparticles can be used for targeted separation and SERS imaging of MDR Salmonella DT104. A targeted photothermal‐lysis experiment, by using 670 nm light at 1.5 W cm^?2 for 10 min, results in selective and irreparable cellular‐damage to MDR Salmonella. We discuss the possible mechanism and operating principle for the targeted separation, label‐free SERS imaging, and photothermal destruction of MDRB by using the popcorn‐shaped magnetic/plasmonic nanotechnology.     

Real-time imaging of surface chemical reactions by electrochemical photothermal reflectance microscopy

Traditional electrochemical measurements based on either current or potential responses only present the average contribution of an entire electrode''s surface. Here, we present an electrochemical photothermal reflectance microscope (EPRM) in which a potential-dependent nonlinear photothermal signal is exploited to map an electrochemical process with sub-micron spatial resolution. By using EPRM, we are able to monitor the photothermal signal of a Pt electrode during the electrochemical reaction at an imaging speed of 0.3 s per frame. The potential-dependent photothermal signal, which is sensitive to the free electron density, clearly revealed the evolution of surface species on the Pt surface. Our results agreed well with the reported spectroelectrochemical techniques under similar conditions but with a much faster imaging speed. We further mapped the potential oscillation during the oxidation of formic acid on the Pt surface. The photothermal images from the Pt electrode well matched the potential change. This technique opens new prospects for real-time imaging of surface chemical reaction to reveal the heterogeneity of electrochemical reactivity, which enables broad applications to the study of catalysis, energy storage, and light harvest systems.

The potential-dependent photothermal signal, which is sensitive to the free electron density, map the evolution of surface species on the electrode in real time.     

LiNbO_3不同晶面的光催化产氢性能

研究了LiNbO3(001)、(100)和(110)晶面的光催化产氢性能。(001)、(100)和(110)3个晶面光催化产氢性能之比为7.8∶1.3∶1.0。LiNbO3[001]晶向存在电偶极矩和自发极化,有利于增加光生电子和空穴的分离效率,减少光生电子和空穴的复合,提高LiNbO3(001)面的光催化活性。LiNbO3(001)面的空穴有效质量最小,有利于光生空穴的迁移,从而减少光生电子和空穴的复合,也有利于光催化性能的提高。     

LiNbO3不同晶面的光催化产氢性能

研究了LiNbO₃（001）、（100）和（110）晶面的光催化产氢性能。（001）、（100）和（110）3个晶面光催化产氢性能之比为7.8：1.3：1.0。LiNbO₃[001]晶向存在电偶极矩和自发极化,有利于增加光生电子和空穴的分离效率,减少光生电子和空穴的复合,提高LiNbO₃（001）面的光催化活性。LiNbO₃（001）面的空穴有效质量最小,有利于光生空穴的迁移,从而减少光生电子和空穴的复合,也有利于光催化性能的提高。     

Multifunctional Uniform Core–Shell Fe3O4@mSiO2 Mesoporous Nanoparticles for Bimodal Imaging and Photothermal Therapy

Multimodal imaging and simultaneous therapy is highly desirable because it can provide complementary information from each imaging modality for accurate diagnosis and, at the same time, afford an imaging‐guided focused tumor therapy. In this study, indocyanine green (ICG), a near‐infrared (NIR) imaging agent and perfect NIR light absorber for laser‐mediated photothermal therapy, was successfully incorporated into superparamagnetic Fe₃O₄@mSiO₂ core–shell nanoparticles to combine the merit of NIR/magnetic resonance (MR) bimodal imaging properties with NIR photothermal therapy. The resultant nanoparticles were homogenously coated with poly(allylamine hydrochloride) (PAH) to make the surface of the composite nanoparticles positively charged, which would enhance cellular uptake driven by electrostatic interactions between the positive surface of the nanoparticles and the negative surface of the cancer cell. A high biocompatibility of the achieved nanoparticles was demonstrated by using a cell cytotoxicity assay. Moreover, confocal laser scanning microscopy (CLSM) observations indicated excellent NIR fluorescent imaging properties of the ICG‐loaded nanoparticles. The relatively high r₂ value (171.6 mM ^?1 s^?1) of the nanoparticles implies its excellent capability as a contrast agent for MRI. More importantly, the ICG‐loaded nanoparticles showed perfect NIR photothermal therapy properties, thus indicating their potential for simultaneous cancer diagnosis as highly effective NIR/MR bimodal imaging probes and for NIR photothermal therapy of cancerous cells.     

二元混合表面活性剂用于窄吸收金纳米棒的无种子合成

利用十六烷基三甲基溴化铵(CTAB)和油酸钠(NaOL)二元混合表面活性剂体系, 开发了一种高质量金纳米棒(AuNRs)的无种子合成方法. 通过透射电子显微镜(TEM)、 紫外-可见-近红外吸收光谱(UV-Vis-NIR)和热成像仪对金纳米棒的形貌、 光学性质及光热性能进行了表征. 实验结果表明, 当NaOL浓度为8.21~11.5 mmol/L时, 能够获得形貌均匀的AuNRs, 其纵向表面等离子体共振吸收(LSPR)在650~1150 nm范围内可调. 该方法制得的样品具有较窄的LSPR半峰宽, 特别是在制备LSPR在近红外二区(NIR-II, 大于1000 nm)的AuNRs方面具有明显优势. 在1064 nm激光的辐照下, 金纳米棒溶液能够快速升温至67 ℃, 光热转换效率可达31.5%, 同时表现出优秀的光热稳定性, 在近红外二区光声成像和光热治疗方面具有良好的应用价值.     

Theranostic Nanoplatform with Hydrogen Sulfide Activatable NIR Responsiveness for Imaging‐Guided On‐Demand Drug Release

NIR light responsive nanoplatforms hold great promise for on‐demand drug release in precision cancer medicine. However, currently available systems utilize “always‐on” photothermal transducers that lack target specificity, and thus inaccurately differentiate tumors from normal tissues. Developed here is a theranostic nanoplatform featuring H₂S‐mediated in situ production of NIR photothermal agents for imaging‐guided and photocontrolled drug release. The system targets H₂S‐rich cancers. This nanoplatform shows H₂S‐activatable NIR‐II emission and NIR light controllable release of the drug Camptothecin‐11. Upon administering the system to HCT116 tumor‐bearing mice, the tumor is greatly suppressed with minimal side effects, arising from the synergy of the cancer‐specific and NIR light activated therapy. This theranostic nanoplatform thus sheds light on precision medicine with guidance through NIR‐II imaging.     

Biodegradable Gold Nanovesicles with an Ultrastrong Plasmonic Coupling Effect for Photoacoustic Imaging and Photothermal Therapy

The hierarchical assembly of gold nanoparticles (GNPs) allows the localized surface plasmon resonance peaks to be engineered to the near‐infrared (NIR) region for enhanced photothermal therapy (PTT). Herein we report a novel theranostic platform based on biodegradable plasmonic gold nanovesicles for photoacoustic (PA) imaging and PTT. The disulfide bond at the terminus of a PEG‐b‐PCL block‐copolymer graft enables dense packing of GNPs during the assembly process and induces ultrastrong plasmonic coupling between adjacent GNPs. The strong NIR absorption induced by plasmon coupling and very high photothermal conversion efficiency (η=37 %) enable simultaneous thermal/PA imaging and enhanced PTT efficacy with improved clearance of the dissociated particles after the completion of PTT. The assembly of various nanocrystals with tailored optical, magnetic, and electronic properties into vesicle architectures opens new possibilities for the construction of multifunctional biodegradable platforms for biomedical applications.     

UCNP–Bi2Se3 Upconverting Nanohybrid for Upconversion Luminescence and CT Imaging and Photothermal Therapy

Non-invasive theranostics that integrate the advantages of multimodality imaging and therapeutics have great potential in the field of biomedicine. Herein, a new nanohybrid based on Bi₂Se₃-conjugated upconversion nanoparticles (UCNPs) has been successfully developed through a simple in situ growth strategy. Under 808 nm near-infrared laser irradiation, the UCNPs can emit bright visible light, whereas the Bi₂Se₃ nanomaterial exhibits efficient photothermal conversion capacity. Moreover, the as-synthesized UCNP–Bi₂Se₃ nanohybrid exhibits efficient cell upconversion luminescence (UCL), reasonable CT imaging, and admirable cancer cell ablation capacity, further emphasizing the efficiency of this strategy for simultaneous UCL imaging and photothermal therapy. The designed theranostic strategy guided by dual-modal imaging endowed with real-time dynamic monitoring, remote controllability, and non-invasiveness makes the UCNP–Bi₂Se₃ nanohybrid an ideal candidate for non-invasive multimodal imaging-guided photothermal therapy for the precise diagnosis and treatment of cancer.     

Plasmonic photothermal catalysis for solar-to-fuel conversion: current status and prospects

Solar-to-fuel conversion through photocatalytic processes is regarded as promising technology with the potential to reduce reliance on dwindling reserves of fossil fuels and to support the sustainable development of our society. However, conventional semiconductor-based photocatalytic systems suffer from unsatisfactory reaction efficiencies due to limited light harvesting abilities. Recent pioneering work from several groups, including ours, has demonstrated that visible and infrared light can be utilized by plasmonic catalysts not only to induce local heating but also to generate energetic hot carriers for initiating surface catalytic reactions and/or modulating the reaction pathways, resulting in synergistically promoted solar-to-fuel conversion efficiencies. In this perspective, we focus primarily on plasmon-mediated catalysis for thermodynamically uphill reactions converting CO₂ and/or H₂O into value-added products. We first introduce two types of mechanism and their applications by which reactions on plasmonic nanostructures can be initiated: either by photo-induced hot carriers (plasmonic photocatalysis) or by light-excited phonons (photothermal catalysis). Then, we emphasize examples where the hot carriers and phonon modes act in concert to contribute to the reaction (plasmonic photothermal catalysis), with special attention given to the design concepts and reaction mechanisms of the catalysts. We discuss challenges and future opportunities relating to plasmonic photothermal processes, aiming to promote an understanding of underlying mechanisms and provide guidelines for the rational design and construction of plasmonic catalysts for highly efficient solar-to-fuel conversion.

Hot carrier activation and photothermal heat can be constructively coupled using plasmonic photothermal catalysts for synergistically promoted solar-to-fuel conversion efficiency.     

Calculated absorption and scattering properties of gold nanoparticles of different size, shape, and composition: applications in biological imaging and biomedicine

The selection of nanoparticles for achieving efficient contrast for biological and cell imaging applications, as well as for photothermal therapeutic applications, is based on the optical properties of the nanoparticles. We use Mie theory and discrete dipole approximation method to calculate absorption and scattering efficiencies and optical resonance wavelengths for three commonly used classes of nanoparticles: gold nanospheres, silica-gold nanoshells, and gold nanorods. The calculated spectra clearly reflect the well-known dependence of nanoparticle optical properties viz. the resonance wavelength, the extinction cross-section, and the ratio of scattering to absorption, on the nanoparticle dimensions. A systematic quantitative study of the various trends is presented. By increasing the size of gold nanospheres from 20 to 80 nm, the magnitude of extinction as well as the relative contribution of scattering to the extinction rapidly increases. Gold nanospheres in the size range commonly employed ( approximately 40 nm) show an absorption cross-section 5 orders higher than conventional absorbing dyes, while the magnitude of light scattering by 80-nm gold nanospheres is 5 orders higher than the light emission from strongly fluorescing dyes. The variation in the plasmon wavelength maximum of nanospheres, i.e., from approximately 520 to 550 nm, is however too limited to be useful for in vivo applications. Gold nanoshells are found to have optical cross-sections comparable to and even higher than the nanospheres. Additionally, their optical resonances lie favorably in the near-infrared region. The resonance wavelength can be rapidly increased by either increasing the total nanoshell size or increasing the ratio of the core-to-shell radius. The total extinction of nanoshells shows a linear dependence on their total size, however, it is independent of the core/shell radius ratio. The relative scattering contribution to the extinction can be rapidly increased by increasing the nanoshell size or decreasing the ratio of the core/shell radius. Gold nanorods show optical cross-sections comparable to nanospheres and nanoshells, however, at much smaller effective size. Their optical resonance can be linearly tuned across the near-infrared region by changing either the effective size or the aspect ratio of the nanorods. The total extinction as well as the relative scattering contribution increases rapidly with the effective size, however, they are independent of the aspect ratio. To compare the effectiveness of nanoparticles of different sizes for real biomedical applications, size-normalized optical cross-sections or per micron coefficients are calculated. Gold nanorods show per micron absorption and scattering coefficients that are an order of magnitude higher than those for nanoshells and nanospheres. While nanorods with a higher aspect ratio along with a smaller effective radius are the best photoabsorbing nanoparticles, the highest scattering contrast for imaging applications is obtained from nanorods of high aspect ratio with a larger effective radius.     

Controlled synthesis of gold nanobelts and nanocombs in aqueous mixed surfactant solutions

Well-defined gold nanobelts as well as unique gold nanocombs made of nanobelts were readily synthesized by the reduction of HAuCl4 with ascorbic acid in aqueous mixed solutions of the cationic surfactant cetyltrimethylammonium bromide (CTAB) and the anionic surfactant sodium dodecylsulfonate (SDSn). Single-crystalline gold nanobelts grown along the <110> and <211> directions were prepared in mixed CTAB-SDSn solutions at 4 and 27 degrees C, respectively. Furthermore, single-crystalline gold nanocombs consisting of a <110>-oriented stem nanobelt and numerous <211>-oriented nanobelts grown perpendicularly on one side of the stem were fabricated by a two-step process with temperature changing from 4 to 27 degrees C. It was proposed that the mixed cationic-anionic surfactants exerted a subtle control on the growth of gold nanocrystals in solution due to the cooperative effect of mixed surfactants. This synthetic strategy may open a new route for the mild fabrication and hierarchical assembly of metal nanobelts in solution. The obtained gold nanobelts showed good electrocatalytic activity toward the oxidation of methanol in alkaline solution; in particular, the electrode modified with the nanobelts obtained at 27 degrees C exhibited an electrocatalytic activity considerably higher than normal polycrystalline gold electrode. Moreover, the gold nanobelts were used as the surface-enhanced Raman scattering (SERS) substrate for detecting the enhanced Raman spectra of p-aminothiophenol (PATP) molecules, and the gold nanobelts obtained at 4 degrees C exhibited an unusual larger enhancement of the b2 modes relative to the a1 modes for the adsorbed PATP molecules.     

Gold Nanorod‐Assembled PEGylated Graphene‐Oxide Nanocomposites for Photothermal Cancer Therapy

Gold nanorod‐attached PEGylated graphene‐oxide (AuNR‐PEG‐GO) nanocomposites were tested for a photothermal platform both in vitro and in vivo. Cytotoxicity of AuNR was reduced after encapsulation with PEG‐GO along with the removal of cetyltrimethylammonium bromide (CTAB) from AuNR by HCl treatment. Cellular internalization of the CTAB‐eliminated AuNR‐PEG‐GO nanocomposites was examined using dark‐field microscopy (DFM), confocal Raman microscopy and transmission electron microscopy (TEM). To determine the photothermal effect of the AuNR‐PEG‐GO nanocomposites, A431 epidermoid carcinoma cells were irradiated with Xe‐lamp light (60 W cm^?2) for 5 min after treatment with the AuNR‐PEG‐GO nanocomposites for 24 h. Cell viability significantly decreased by ~40% when the AuNR‐PEG‐GO‐encapsulated nanocomposites were irradiated with light as compared with the cells treated with only the AuNR‐PEG‐GO nanocomposites without any illumination. In vivo tumor experiments also indicated that HCl‐treated AuNR‐PEG‐GO nanocomposites might efficiently reduce tumor volumes via photothermal processes. Our graphene and AuNR nanocomposites will be useful for an effective photothermal therapy.     

Ultrasmall reduced graphene oxide with high near-infrared absorbance for photothermal therapy

We developed nanosized, reduced graphene oxide (nano-rGO) sheets with high near-infrared (NIR) light absorbance and biocompatibility for potential photothermal therapy. The single-layered nano-rGO sheets were ～20 nm in average lateral dimension, functionalized noncovalently by amphiphilic PEGylated polymer chains to render stability in biological solutions and exhibited 6-fold higher NIR absorption than nonreduced, covalently PEGylated nano-GO. Attaching a targeting peptide bearing the Arg-Gly-Asp (RGD) motif to nano-rGO afforded selective cellular uptake in U87MG cancer cells and highly effective photoablation of cells in vitro. In the absence of any NIR irradiation, nano-rGO exhibited little toxicity in vitro at concentrations well above the doses needed for photothermal heating. This work established nano-rGO as a novel photothermal agent due to its small size, high photothermal efficiency, and low cost as compared to other NIR photothermal agents including gold nanomaterials and carbon nanotubes.     

Cancer cell imaging and photothermal therapy in the near-infrared region by using gold nanorods

Due to strong electric fields at the surface, the absorption and scattering of electromagnetic radiation by noble metal nanoparticles are strongly enhanced. These unique properties provide the potential of designing novel optically active reagents for simultaneous molecular imaging and photothermal cancer therapy. It is desirable to use agents that are active in the near-infrared (NIR) region of the radiation spectrum to minimize the light extinction by intrinsic chromophores in native tissue. Gold nanorods with suitable aspect ratios (length divided by width) can absorb and scatter strongly in the NIR region (650-900 nm). In the present work, we provide an in vitro demonstration of gold nanorods as novel contrast agents for both molecular imaging and photothermal cancer therapy. Nanorods are synthesized and conjugated to anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibodies and incubated in cell cultures with a nonmalignant epithelial cell line (HaCat) and two malignant oral epithelial cell lines (HOC 313 clone 8 and HSC 3). The anti-EGFR antibody-conjugated nanorods bind specifically to the surface of the malignant-type cells with a much higher affinity due to the overexpressed EGFR on the cytoplasmic membrane of the malignant cells. As a result of the strongly scattered red light from gold nanorods in dark field, observed using a laboratory microscope, the malignant cells are clearly visualized and diagnosed from the nonmalignant cells. It is found that, after exposure to continuous red laser at 800 nm, malignant cells require about half the laser energy to be photothermally destroyed than the nonmalignant cells. Thus, both efficient cancer cell diagnostics and selective photothermal therapy are realized at the same time.