Controlled Synthesis of Ag2Te@Ag2S Core–Shell Quantum Dots with Enhanced and Tunable Fluorescence in the Second Near‐Infrared Window

Fluorescence in the second near‐infrared window (NIR‐II, 900–1700 nm) has drawn great interest for bioimaging, owing to its high tissue penetration depth and high spatiotemporal resolution. NIR‐II fluorophores with high photoluminescence quantum yield (PLQY) and stability along with high biocompatibility are urgently pursued. In this work, a Ag‐rich Ag₂Te quantum dots (QDs) surface with sulfur source is successfully engineered to prepare a larger bandgap of Ag₂S shell to passivate the Ag₂Te core via a facile colloidal route, which greatly enhances the PLQY of Ag₂Te QDs and significantly improves the stability of Ag₂Te QDs. This strategy works well with different sized core Ag₂Te QDs so that the NIR‐II PL can be tuned in a wide range. In vivo imaging using the as‐prepared Ag₂Te@Ag₂S QDs presents much higher spatial resolution images of organs and vascular structures as compared with the same dose of Ag₂Te nanoprobes administrated, suggesting the success of the core–shell synthetic strategy and the potential biomedical applications of core–shell NIR‐II nanoprobes.     

Preoperative Detection and Intraoperative Visualization of Brain Tumors for More Precise Surgery: A New Dual‐Modality MRI and NIR Nanoprobe

In clinical practice, it is difficult to identify tumor margins during brain surgery due to its inherent infiltrative character. Herein, a unique dual‐modality nanoprobe (Gd‐DOTA‐Ag₂S QDs, referred as Gd‐Ag₂S nanoprobe) is reported, which integrates advantages of the deep tissue penetration of enhanced magnetic resonance (MR) imaging of Gd and the high signal‐to‐noise ratio and high spatiotemporal resolution of fluorescence imaging in the second near‐infrared window (NIR‐II) of Ag₂S quantum dots (QDs). Due to the abundant tumor angiogenesis and the enhanced permeability and retention effect in the tumor, a brain tumor (U87MG) in a mouse model is clearly delineated in situ with the help of the Gd assisted T1 MR imaging and the intraoperative resection of the tumor is precisely accomplished under the guidance of NIR‐II fluorescence imaging of Ag₂S QDs after intravenous injection of Gd‐Ag₂S nanoprobe. Additionally, no histologic changes are observed in the main organs of the mouse after administration of Gd‐Ag₂S nanoprobe for 1 month, indicating the high biocompatibility of the nanoprobe. We expect that such a novel “Detection and Operation” strategy based on Gd‐Ag₂S nanoprobe is promising in future clinical applications.     

Controllable preparation of Ag2S quantum dots with size-dependent fluorescence and cancer photothermal therapy

Although Ag₂S quantum dots (QDs) have attracted extensive attention in the fields of diagnosis and therapy, it is still a challenge to prepare Ag₂S QDs with well-controlled size distribution. Herein, size-tunable Ag₂S QDs with glutathione (GSH) as ligands were prepared via a facile aqueous precipitation method. The QDs are precisely prepared through carefully controlled growth of Ag2S QDs by varying the heating time. Morphology and structure characterization verify that Ag₂S QDs with 2.0–5.8 nm in diameter are coordinated with GSH through thiol group. The as-prepared Ag₂S QDs exhibit broad absorption spectra and narrow fluorescence emission spectra in the near-infrared region. Meanwhile, the QDs perform excellent and stable photothermal effect with a photothermal conversion efficiency up to 58.6%. More importantly, it is found that the size of Ag₂S QDs has a significant influence on the fluorescence intensity and photothermal effect. The cell viability evaluation in vitro demonstrates that Ag₂S QDs have low cytotoxicity to 293 T cells and Hela cells by methyl thiazolyl tetrazolium test. This paper proposes a convenient route to prepare unique Ag₂S QDs, which are capable to act as ideal theranostics probes for photothermal therapy and simultaneously monitoring the therapeutic effect for effective cancer treatment.     

An Activatable Phototheranostic Nanoplatform for Tumor Specific NIR-II Fluorescence Imaging and Synergistic NIR-II Photothermal-Chemodynamic Therapy

The phototheranostics in the second near-infrared window (NIR-II) have proven to be promising for the precise cancer theranostics. However, the non-responsive and “always on” imaging mode lacks the selectivity, leading to the poor diagnosis specificity. Herein, a tumor microenvironment (TME) activated NIR-II phototheranostic nanoplatform (Ag₂S-Fe(III)-DBZ Pdots, AFD NPs) is designed based on the principle of Förster resonance energy transfer (FRET). The AFD NPs are fabricated through self-assembly of Ag₂S QDs (NIR-II fluorescence probe) and ultra-small semiconductor polymer dots (DBZ Pdots, NIR-II fluorescence quencher) utilizing Fe(III) as coordination nodes. In normal tissues, the AFD NPs maintain in “off” state, due to the FRET between Ag₂S QDs and DBZ Pdots. However, the NIR-II fluorescence signal of AFD NPs can be rapidly “turn on” by the overexpressed GSH in tumor tissues, achieving a superior tumor-to-normal tissue (T/NT) signal ratio. Moreover, the released Pdots and reduced Fe(II) ions provide NIR-II photothermal therapy (PTT) and chemodynamic therapy (CDT), respectively. The GSH depletion and NIR-II PTT effect further aggravate CDT mediated oxidative damage toward tumors, achieving the synergistic anti-tumor therapeutic effect. The work provides a promising strategy for the development of TME activated NIR-II phototheranostic nanoprobes.     

Novel Mn3[Co(CN)6]2@SiO2@Ag Core–Shell Nanocube: Enhanced Two‐Photon Fluorescence and Magnetic Resonance Dual‐Modal Imaging‐Guided Photothermal and Chemo‐therapy

The versatile Mn₃[Co(CN)₆]₂@SiO₂@Ag core–shell NCs are prepared by a simple coprecipitation method. Ag nanoparticles with an average diameter of 12 nm deposited on the surface of Mn₃[Co(CN)₆]₂@SiO₂ through S–Ag bonding are fabricated in ethanol solution by reducing silver nitrate (AgNO₃) with NaBH₄. The NCs possess T₁–T₂ dual‐modal magnetic resonance imaging ability. The inner Prussian blue analogs (PBAs) Mn₃[Co(CN)₆]₂ exhibit bright two‐photon fluorescence (TPF) imaging when excited at 730 nm. Moreover, the TPF imaging intensity displays 1.85‐fold enhancement after loading of Ag nanoparticles. Besides, the sample also has multicolor fluorescence imaging ability under 403, 488, and 543 nm single photon excitation. The as‐synthesized Mn₃[Co(CN)₆]₂@SiO₂@Ag NCs show a DOX loading capacity of 600 mg g⁻¹ and exhibit an excellent ability of near‐infrared (NIR)‐responsive drug release and photothermal therapy (PTT) which is induced from the relative high absorbance in NIR region. The combined chemotherapy and PTT against cancer cells in vitro test shows high therapeutic efficiency. The multimodal treatment and imaging could lead to this material a potential multifunctional system for biomedical diagnosis and therapy.     

Biodegradable Bi2O2Se Quantum Dots for Photoacoustic Imaging‐Guided Cancer Photothermal Therapy

As new 2D layered nanomaterials, Bi₂O₂Se nanoplates have unique semiconducting properties that can benefit biomedical applications. Herein, a facile top‐down approach for the synthesis of Bi₂O₂Se quantum dots (QDs) in a solution is described. The Bi₂O₂Se QDs with a size of 3.8 nm and thickness of 1.9 nm exhibit a high photothermal conversion coefficient of 35.7% and good photothermal stability. In vitro and in vivo assessments demonstrate that the Bi₂O₂Se QDs possess excellent photoacoustic (PA) performance and photothermal therapy (PTT) efficiency. After systemic administration, the Bi₂O₂Se QDs accumulate passively in tumors enabling efficient PA imaging of the entire tumors to facilitate imaging‐guided PTT without obvious toxicity. Furthermore, the Bi₂O₂Se QDs which exhibit degradability in aqueous media not only have sufficient stability during in vivo circulation to perform the designed therapeutic functions, but also can be discharged harmlessly from the body afterward. The results reveal the great potential of Bi₂O₂Se QDs as a biodegradable multifunctional agent in medical applications.     

Core–Satellite Polydopamine–Gadolinium‐Metallofullerene Nanotheranostics for Multimodal Imaging Guided Combination Cancer Therapy

Integration of magnetic resonance imaging (MRI) and other imaging modalities is promising to furnish complementary information for accurate cancer diagnosis and imaging‐guided therapy. However, most gadolinium (Gd)–chelator MR contrast agents are limited by their relatively low relaxivity and high risk of released‐Gd‐ions‐associated toxicity. Herein, a radionuclide‐⁶⁴Cu‐labeled doxorubicin‐loaded polydopamine (PDA)–gadolinium‐metallofullerene core–satellite nanotheranostic agent (denoted as CDPGM) is developed for MR/photoacoustic (PA)/positron emission tomography (PET) multimodal imaging‐guided combination cancer therapy. In this system, the near‐infrared (NIR)‐absorbing PDA acts as a platform for the assembly of different moieties; Gd₃N@C₈₀, a kind of gadolinium metallofullerene with three Gd ions in one carbon cage, acts as a satellite anchoring on the surface of PDA. The as‐prepared CDPGM NPs show good biocompatibility, strong NIR absorption, high relaxivity (r ₁ = 14.06 mM^?1 s^?1), low risk of release of Gd ions, and NIR‐triggered drug release. In vivo MR/PA/PET multimodal imaging confirms effective tumor accumulation of the CDPGM NPs. Moreover, upon NIR laser irradiation, the tumor is completely eliminated with combined chemo‐photothermal therapy. These results suggest that the CDPGM NPs hold great promise for cancer theranostics.     

NIR‐Responsive Polycationic Gatekeeper‐Cloaked Hetero‐Nanoparticles for Multimodal Imaging‐Guided Triple‐Combination Therapy of Cancer

Responsive multifunctional organic/inorganic nanohybrids are promising for effective and precise imaging‐guided therapy of cancer. In this work, a near‐infrared (NIR)‐triggered multifunctional nanoplatform comprising Au nanorods (Au NRs), mesoporous silica, quantum dots (QDs), and two‐armed ethanolamine‐modified poly(glycidyl methacrylate) with cyclodextrin cores (denoted as CD‐PGEA) has been successfully fabricated for multimodal imaging‐guided triple‐combination treatment of cancer. A hierarchical hetero‐structure is first constructed via integration of Au NRs with QDs through a mesoporous silica intermediate layer. The X‐ray opacity and photoacoustic (PA) property of Au NRs are utilized for tomography (CT) and PA imaging, and the imaging sensitivity is further enhanced by the fluorescent QDs. The mesoporous feature of silica allows the loading of a typical antitumor drug, doxorubicin (DOX), which are sealed by the polycationic gatekeepers, low toxic hydroxyl‐rich CD‐PGEA/pDNA complexes, realizing the co‐delivery of drug and gene. The photothermal effect of Au NRs is utilized for photothermal therapy (PTT). More interestingly, such photothermal effect also induces a cascade of NIR‐triggered release of DOX through the facilitated detachment of CD‐PGEA gatekeepers for controlled chemotherapy. The resultant chemotherapy and gene therapy for glioma tumors are complementary for the efficiency of PTT. This work presents a novel responsive multifunctional imaging‐guided therapy platform, which combines fluorescent/PA/CT imaging and gene/chemo/photothermal therapy into one nanostructure.     

A Hollow‐Structured CuS@Cu2S@Au Nanohybrid: Synergistically Enhanced Photothermal Efficiency and Photoswitchable Targeting Effect for Cancer Theranostics

It is of great importance in drug delivery to fabricate multifunctional nanocarriers with intelligent targeting properties, for cancer diagnosis and therapy. Herein, hollow‐structured CuS@Cu₂S@Au nanoshell/satellite nanoparticles are designed and synthesized for enhanced photothermal therapy and photoswitchable targeting theranostics. The remarkably improved photothermal conversion efficiency of CuS@Cu₂S@Au under 808 nm near‐infrared (NIR) laser irradiation can be explained by the reduced bandgap and more circuit paths for electron transitions for CuS and Cu₂S modified with Au nanoparticles, as calculated by the Vienna ab initio simulation package, based on density functional theory. By modification of thermal‐isomerization RGD targeting molecules and thermally sensitive copolymer on the surface of nanoparticles, the transition of the shielded/unshielded mode of RGD (Arg‐Gly‐Asp) targeting molecules and shrinking of the thermally sensitive polymer by NIR photoactivation can realize a photoswitchable targeting effect. After loading an anticancer drug doxorubicin in the cavity of CuS@Cu₂S@Au, the antitumor therapy efficacy is greatly enhanced by combining chemo‐ and photothermal therapy. The reported nanohybrid can also act as a photoacoustic imaging agent and an NIR thermal imaging agent for real‐time imaging, which provides a versatile platform for multifunctional theranostics and stimuli‐responsive targeted cancer therapy.     

Layered MoS2 Hollow Spheres for Highly‐Efficient Photothermal Therapy of Rabbit Liver Orthotopic Transplantation Tumors

Combining photothermal therapy (PTT) with clinical technology to kill cancer via overcoming the low tumor targeting and poor therapy efficiency has great potential in basic and clinical researches. A brand‐new MoS₂ nanostructure is designed and fabricated, i.e., layered MoS₂ hollow spheres (LMHSs) with strong absorption in near‐infrared region (NIR) and high photothermal conversion efficiency via a simple and fast chemical aerosol flow method. Owing to curving layered hollow spherical structure, the as‐prepared LMHSs exhibit unique electronic properties comparing with MoS₂ nanosheets. In vitro and in vivo studies demonstrate their high photothermal ablation of cell and tumor elimination rate by single NIR light irradiation. Systematic acute toxicity study indicates that these LMHSs have negligible toxic effects to normal tissues and blood. Remarkably, minimally invasive interventional techniques are introduced to improve tumor targeting of PTT agents for the first time. To explore PTT efficiency on orthotopic transplantation tumors, New Zealand white rabbits with VX₂ tumor in liver are used as animal models. The effective elimination of tumors is successfully realized by PTT under the guidance of digital subtraction angiography, computed tomography, and thermal imaging, which provides a new way for tumor‐targeting delivery and cancer theranostic application.     

The Nanoassembly of an Intrinsically Cytotoxic Near‐Infrared Dye for Multifunctionally Synergistic Theranostics

The combination of diagnostic and therapeutic functions in a single theranostic nanoagent generally requires the integration of multi‐ingredients. Herein, a cytotoxic near‐infrared (NIR) dye (IR‐797) and its nanoassembly are reported for multifunctional cancer theranostics. The hydrophobic IR‐797 molecules are self‐assembled into nanoparticles, which are further modified with an amphiphilic polymer (C18PMH‐PEG5000) on the surface. The prepared PEG‐IR‐797 nanoparticles (PEG‐IR‐797 NPs) possess inherent cytotoxicity from the IR‐797 dye and work as a chemotherapeutic drug which induces apoptosis of cancer cells. The IR‐797 NPs are found to have an ultrahigh mass extinction coefficient (444.3 L g^?1 cm^?1 at 797 nm and 385.9 L g^?1 cm^?1 at 808 nm) beyond all reported organic nanomaterials (<40 L g^?1 cm^?1) for superior photothermal therapy (PTT). In addition, IR‐797 shows some aggregation‐induced‐emission (AIE) properties. Combining the merits of good NIR absorption, high photothermal energy conversion efficiency, and AIE, makes the PEG‐IR‐797 NPs useful for multimodal NIR AIE fluorescence, photoacoustic, and thermal imaging‐guided therapy. The research exhibits the possibility of using a single ingredient and entity to perform multimodal NIR fluorescence, photoacoustic, and thermal imaging‐guided chemo‐/photothermal combination therapy, which may trigger wide interest from the fields of nanomedicine and medicinal chemistry to explore multifunctional theranostic organic molecules.     

Nanocatalysts‐Augmented and Photothermal‐Enhanced Tumor‐Specific Sequential Nanocatalytic Therapy in Both NIR‐I and NIR‐II Biowindows

The tumor microenvironment (TME) has been increasingly recognized as a crucial contributor to tumorigenesis. Based on the unique TME for achieving tumor‐specific therapy, here a novel concept of photothermal‐enhanced sequential nanocatalytic therapy in both NIR‐I and NIR‐II biowindows is proposed, which innovatively changes the condition of nanocatalytic Fenton reaction for production of highly efficient hydroxyl radicals (?OH) and consequently suppressing the tumor growth. Evidence suggests that glucose plays a vital role in powering cancer progression. Encouraged by the oxidation of glucose to gluconic acid and H₂O₂ by glucose oxidase (GOD), an Fe₃O₄/GOD‐functionalized polypyrrole (PPy)‐based composite nanocatalyst is constructed to achieve diagnostic imaging‐guided, photothermal‐enhanced, and TME‐specific sequential nanocatalytic tumor therapy. The consumption of intratumoral glucose by GOD leads to the in situ elevation of the H₂O₂ level, and the integrated Fe₃O₄ component then catalyzes H₂O₂ into highly toxic ?OH to efficiently induce cancer‐cell death. Importantly, the high photothermal‐conversion efficiency (66.4% in NIR‐II biowindow) of the PPy component elevates the local tumor temperature in both NIR‐I and NIR‐II biowindows to substaintially accelerate and improve the nanocatalytic disproportionation degree of H₂O₂ for enhancing the nanocatalytic‐therapeutic efficacy, which successfully achieves a remarkable synergistic anticancer outcome with minimal side effects.     

Rhenium‐188 Labeled Tungsten Disulfide Nanoflakes for Self‐Sensitized,Near‐Infrared Enhanced Radioisotope Therapy

Radioisotope therapy (RIT), in which radioactive agents are administered or implanted into the body to irradiate tumors from the inside, is a clinically adopted cancer treatment method but still needs improvement to enhance its performances. Herein, it is found that polyethylene glycol (PEG) modified tungsten disulfide (WS₂) nanoflakes can be easily labeled by ¹⁸⁸Re, a widely used radioisotope for RIT, upon simple mixing. Like other high‐Z elements acting as radiosensitizers, tungsten in the obtained ¹⁸⁸Re‐WS₂‐PEG would be able to absorb ionization radiation generated from ¹⁸⁸Re, enabling ‘‘self‐sensitization’’ to enhance the efficacy of RIT as demonstrated in carefully designed in vitro experiments of this study. In the meanwhile, the strong NIR absorbance of WS₂‐PEG could be utilized for NIR light‐induced photothermal therapy (PTT), which if applied on tumors would be able to greatly relieve their hypoxia state and help to overcome hypoxia‐associated radioresistance of tumors. Therefore, with ¹⁸⁸Re‐WS₂‐PEG as a multifunctional agent, which shows efficient passive tumor homing after intravenous injection, in vivo self‐sensitized, NIR‐enhanced RIT cancer treatment is realized, achieving excellent tumor killing efficacy in a mouse tumor model. This work presents a new concept of applying nanotechnology in RIT, by delivering radioisotopes into tumors, self‐sensitizing the irradiation‐induced cell damage, and modulating the tumor hypoxia state to further enhance the therapeutic outcomes.     

Ultrasmall Pb:Ag2S Quantum Dots with Uniform Particle Size and Bright Tunable Fluorescence in the NIR‐II Window

Ag₂S quantum dots (QDs) are well‐known near‐infrared fluorophores and have attracted great interest in biomedical labeling and imaging in the past years. However, their photoluminescence efficiency is hard to compete with Cd‐, Pb‐based QDs. The high Ag⁺ mobility in Ag₂S crystal, which causes plenty of cation deficiency and crystal defects, may be responsible mainly for the low photoluminescence quantum yield (PLQY) of Ag₂S QDs. Herein, a cation‐doping strategy is presented via introducing a certain dosage of transition metal Pb²⁺ ions into Ag₂S nanocrystals to mitigate this intrinsic shortcoming. The Pb‐doped Ag₂S QDs (designated as Pb:Ag₂S QDs) present a renovated crystal structure and significantly enhanced optical performance. Moreover, by simply adjusting the levels of Pb doping in the doped nanocrystals, Pb:Ag₂S QDs with bright emission (PLQY up to 30.2%) from 975 to 1242 nm can be prepared without altering the ultrasmall particle size (≈2.7–2.8 nm). Evidently, this cation‐doping strategy facilitates both the renovation of crystal structure of Ag₂S QDs and modulation of their optical properties.     

Photosensitizer‐Conjugated Albumin−Polypyrrole Nanoparticles for Imaging‐Guided In Vivo Photodynamic/Photothermal Therapy

Conjugated polymers with strong absorbance in the near‐infrared (NIR) region have been widely explored as photothermal therapy agents due to their excellent photostability and high photothermal conversion efficiency. Herein, polypyrrole (PPy) nanoparticles are fabricated by using bovine serum albumin (BSA) as the stabilizing agent, which if preconjugated with photosensitizer chlorin e6 (Ce6) could offer additional functionalities in both imaging and therapy. The obtained PPy@BSA‐Ce6 nanoparticles exhibit little dark toxicity to cells, and are able to trigger both photodynamic therapy (PDT) and photothermal therapy (PTT). As a fluorescent molecule that in the meantime could form chelate complex with Gd³⁺, Ce6 in PPy@BSA‐Ce6 nanoparticles after being labeled with Gd³⁺ enables dual‐modal fluorescence and magnetic resonance (MR) imaging, which illustrate strong tumor uptake of those nanoparticles after intravenous injection into tumor‐bearing mice. In vivo combined PDT and PTT treatment is then carried out after systemic administration of PPy@BSA‐Ce6, achieving a remarkably improved synergistic therapeutic effect compared to PDT or PTT alone. Hence, a rather simple one‐step approach to fabricate multifunctional nanoparticles based on conjugated polymers, which appear to be promising in cancer imaging and combination therapy, is presented.     

Rational Design of Multifunctional Fe@γ‐Fe2O3@H‐TiO2 Nanocomposites with Enhanced Magnetic and Photoconversion Effects for Wide Applications: From Photocatalysis to Imaging‐Guided Photothermal Cancer Therapy

Titanium dioxide (TiO₂) has been widely investigated and used in many areas due to its high refractive index and ultraviolet light absorption, but the lack of absorption in the visible–near infrared (Vis–NIR) region limits its application. Herein, multifunctional Fe@γ‐Fe₂O₃@H‐TiO₂ nanocomposites (NCs) with multilayer‐structure are synthesized by one‐step hydrogen reduction, which show remarkably improved magnetic and photoconversion effects as a promising generalists for photocatalysis, bioimaging, and photothermal therapy (PTT). Hydrogenation is used to turn white TiO₂ in to hydrogenated TiO₂ (H‐TiO₂), thus improving the absorption in the Vis–NIR region. Based on the excellent solar‐driven photocatalytic activities of the H‐TiO₂ shell, the Fe@γ‐Fe₂O₃ magnetic core is introduced to make it convenient for separating and recovering the catalytic agents. More importantly, Fe@γ‐Fe₂O₃@H‐TiO₂ NCs show enhanced photothermal conversion efficiency due to more circuit loops for electron transitions between H‐TiO₂ and γ‐Fe₂O₃, and the electronic structures of Fe@γ‐Fe₂O₃@H‐TiO₂ NCs are calculated using the Vienna ab initio simulation package based on the density functional theory to account for the results. The reported core–shell NCs can serve as an NIR‐responsive photothermal agent for magnetic‐targeted photothermal therapy and as a multimodal imaging probe for cancer including infrared photothermal imaging, magnetic resonance imaging, and photoacoustic imaging.     

Graphene Nanomesh Promises Extremely Efficient In Vivo Photothermal Therapy

Reduced graphene oxide nanomesh (rGONM), as one of the recent structures of graphene with a surprisingly strong near‐infrared (NIR) absorption, is used for achieving ultraefficient photothermal therapy. First, by using TiO₂ nanoparticles, graphene oxide nanoplatelets (GONPs) are transformed into GONMs through photocatalytic degradation. Then rGONMs functionalized by polyethylene glycol (PEG), arginine–glycine–aspartic acid (RGD)‐based peptide, and cyanine 7 (Cy7) are utilized for in vivo tumor targeting and fluorescence imaging of human glioblastoma U87MG tumors having α_νβ₃ integrin receptors, in mouse models. The rGONM‐PEG suspension (1 μg mL^?1) exhibits about 4.2‐ and 22.4‐fold higher NIR absorption at 808 nm than rGONP‐PEG and graphene oxide (GO) with lateral dimensions of ≈60 nm and ≈2 μm. In vivo fluorescence imaging demonstrates high selective tumor uptake of rGONM‐PEG‐Cy7‐RGD in mice bearing U87MG cells. The excellent NIR absorbance and tumor targeting of rGONM‐PEG‐Cy7‐RGD results in an ultraefficient photothermal therapy (100% tumor elimination 48 h after intravenous injection of an ultralow concentration (10 μg mL^?1) of rGONM‐PEG‐Cy7‐RGD followed by irradiation with an ultralow laser power (0.1 W cm^?2) for 7 min), whereas the corresponding rGO‐ and rGONP‐based composites do not present remarkable treatments under the same conditions. All the mice treated by rGONM‐PEG‐Cy7‐RGD survived over 100 days, whereas the mice treated by other usual rGO‐based composites were dead before 38 days. The results introduce rGONM as one of the most promising nanomaterials in developing highly desired ultraefficient photothermal therapy.     

Dual‐Peak Absorbing Semiconducting Copolymer Nanoparticles for First and Second Near‐Infrared Window Photothermal Therapy: A Comparative Study

Near‐infrared (NIR) light is widely used for noninvasive optical diagnosis and phototherapy. However, current research focuses on the first NIR window (NIR‐I, 650–950 nm), while the second NIR window (NIR‐II, 1000–1700 nm) is far less exploited. The development of the first organic photothermal nanoagent (SPN_I‐II) with dual‐peak absorption in both NIR windows and its utilization in photothermal therapy (PTT) are reported herein. Such a nanoagent comprises a semiconducting copolymer with two distinct segments that respectively and identically absorb NIR light at 808 and 1064 nm. With the photothermal conversion efficiency of 43.4% at 1064 nm generally higher than other inorganic nanomaterials, SPN_I‐II enables superior deep‐tissue heating at 1064 nm over that at 808 nm at their respective safety limits. Model deep‐tissue cancer PTT at a tissue depth of 5 mm validates the enhanced antitumor effect of SPN_I‐II when shifting laser irradiation from the NIR‐I to the NIR‐II window. The good biodistribution and facile synthesis of SPN_I‐II also allow it to be doped with an NIR dye for fluorescence‐imaging‐guided NIR‐II PTT through systemic administration. Thus, this study paves the way for the development of new polymeric nanomaterials to advance phototherapy.     

Iodine‐Rich Semiconducting Polymer Nanoparticles for CT/Fluorescence Dual‐Modal Imaging‐Guided Enhanced Photodynamic Therapy

Photodynamic therapy (PDT) is a promising technique for cancer therapy, providing good therapeutic efficacy with minimized side effect. However, the lack of oxygen supply in the hypoxic tumor site obviously restricts the generation of singlet oxygen (¹O₂), thus limiting the efficacy of PDT. So far, the strategies to improve PDT efficacy usually rely on complicated nanosystems, which require sophisticated design or complex synthetic procedure. Herein, iodine‐rich semiconducting polymer nanoparticles (SPN‐I) for enhanced PDT, using iodine‐induced intermolecular heavy‐atom effect to elevate the ¹O₂ generation, are designed and prepared. The nanoparticles are composed of a near‐infrared (NIR) absorbing semiconducting polymer (PCPDTBT) serving as the photosensitizer and source of fluorescence signal, and an iodine‐grafted amphiphilic diblock copolymer (PEG‐PHEMA‐I) serving as the ¹O₂ generation enhancer and nanocarrier. Compared with SPN composed of PEG‐b‐PPG‐b‐PEG and PCPDTBT (SPN‐P), SPN‐I can enhance the ¹O₂ generation by 1.5‐fold. In addition, SPN‐I have high X‐ray attenuation coefficient because of the high density of iodine in PEG‐PHEMA‐I, providing SPN‐I the ability of use with computed tomography (CT) and fluorescence dual‐modal imaging. The study thus provides a simple nanotheranostic platform composed of two components for efficient CT/fluorescence dual‐modal imaging‐guided enhanced PDT.     

Near-infrared-emitting colloidal Ag<Subscript>2</Subscript>S quantum dots excited by an 808 nm diode laser

Thioglycolic acid (TGA)-coated colloidal Ag₂S quantum dots (QDs) emitting in the near-infrared (NIR) region upon excitation by an 808 nm diode laser were synthesized. The observed photoluminescence (PL) was attributed to the presence of ligand-modified Ag₂S on the QD surfaces and could be easily controlled by a simple dilution process due to the concentration-dependent surface structure of the colloidal QDs. Upon dilution of the solution, the PL intensity initially increased before later decreasing, with a blueshift being observed in the PL spectra. These phenomena can be accounted for by the aggregation of QDs due to a decrease in the content of ligand-modified Ag₂S on the QD surfaces upon dilution, which in turn affected the fluorescence resonance energy transfer (FRET), and re-emission of the surface energy level.