A Photolabile Semiconducting Polymer Nanotransducer for Near-Infrared Regulation of CRISPR/Cas9 Gene Editing

Noninvasive regulation of CRISPR/Cas9 gene editing is conducive to understanding of gene function and development of gene therapy; however, it remains challenging. Herein, a photolabile semiconducting polymer nanotransducer (pSPN) is synthesized to act as the gene vector to deliver CRISPR/Cas9 plasmids into cells and also as the photoregulator to remotely activate gene editing. pSPN comprises a ¹ O₂ -generating backbone grafted with polyethylenimine brushes through ¹ O₂ -cleavable linkers. NIR photoirradiation spontaneously triggers the cleavage of gene vectors from pSPN, resulting in the release of CRISPR/Cas9 plasmids and subsequently initiating gene editing. This system affords 15- and 1.8-fold enhancement in repaired gene expression relative to the nonirradiated controls in living cells and mice, respectively. As this approach does not require any specific modifications on biomolecular components, pSPN represents the first generic nanotransducer for in vivo regulation of CRISPR/Cas9 gene editing.

Manipulating Nonradiative Decay Channel by Intermolecular Charge Transfer for Exceptionally Improved Photothermal Conversion

In-depth studies of nonradiative (NR) decay, seeking to maximize NR decay rate or manipulate other NR decay channels, are of greatest significance for improving the photothermal conversion efficiency (η) of organic materials for phototheranostics; however, to date, relevant work remains scarce. Here, we present an insightful study of NR decay in BODIPY (BDP) dye, in an aggregated state, i.e., in BDP nanoparticles (BDP NPs), which show an efficient additional NR decay channel from the aggregation-stabilized intermolecular charge transfer (CT) state, resulting in exceptionally high η (61%) for highly efficient phototheranostics in vivo. BDP NPs exhibit two ultrafast NR decay channels with ultrashort lifetimes of 1.7 and 50 ps, which is in stark contrast to the only S₁ → S₀ NR channel with a long lifetime of 373 ps in the isolated BDP dye. More importantly, the ultrafast NR channel (1.7 ps) in BDP NPs depletes a substantial portion of the excited-state population (71%), which accounts for its much better photothermal effect as compared with the isolated BDP dye. Finally, BDP NPs display a highly efficient photoacoustic imaging (PAI) guided photothermal therapy (PTT) of tumors in live mice. This study presents a deeper fundamental understanding of NR decay in organic materials, setting a valuable guideline that may be widely applicable to similar molecular structure to develop more advanced organic materials not only for photothermal-related applications.

Radiolabeling nanomaterials for multimodality imaging: New insights into nuclear medicine and cancer diagnosis

Nuclear medicine imaging has been developed as a powerful diagnostic approach for cancers by detecting gamma rays directly or indirectly from radionuclides to construct images with beneficial characteristics of high sensitivity, infinite penetration depth and quantitative capability. Current nuclear medicine imaging modalities mainly include single-photon emission computed tomography (SPECT) and positron emission tomography (PET) that require administration of radioactive tracers. In recent years, a vast number of radioactive tracers have been designed and constructed to improve nuclear medicine imaging performance toward early and accurate diagnosis of cancers. This review will discuss recent progress of nuclear medicine imaging tracers and associated biomedical imaging applications. Radiolabeling nanomaterials for rational development of tracers will be comprehensively reviewed with highlights on radiolabeling approaches (surface coupling, inner incorporation and interface engineering), providing profound understanding on radiolabeling chemistry and the associated imaging functionalities. The applications of radiolabeled nanomaterials in nuclear medicine imaging-related multimodality imaging will also be summarized with typical paradigms described. Finally, key challenges and new directions for future research will be discussed to guide further advancement and practical use of radiolabeled nanomaterials for imaging of cancers.

Oxygen self-sufficient NIR-activatable liposomes for tumor hypoxia regulation and photodynamic therapy

The inherent hypoxic environment in tumors severely resists the efficacy of photodynamic therapy. To address this problem, herein, the strategy of using oxygen self-sufficient liposomes (denoted as CaO2/B1/NH4HCO3 lipo), which contained aza-BODIPY dye (B1) and CaO2 nanoparticles in the hydrophobic layer and NH4HCO3 in the hydrophilic cavity, was presented to overcome hypoxia-associated photodynamic resistance. Under near-infrared (NIR) irradiation, NIR-absorbable B1 was activated to induce hyperthermia and further triggered the decomposition of NH4HCO3. Subsequently, with the aid of NH4HCO3 and CaO2 nanoparticles, oxygen was rapidly and self-sufficiently generated, during which clean by-products were produced. Furthermore, the increased amount of oxygen promoted the singlet oxygen production in the presence of B1, which served as a photosensitizer because of the heavy atom effect. The oxygen self-sufficient system improved the anticancer efficiency and alleviated the hypoxic environment in vivo, which demonstrated a valuable attempt to regulate intratumoral hypoxia and overcome the limitation of current photodynamic therapy systems. To our knowledge, this highlights the first example of using NIR light to activate CaO2 nanoparticle-containing liposomes for the modulation of the hypoxic environment in tumors.

A photochromic upconversion nanoarchitecture: towards activatable bioimaging and dual NIR light-programmed singlet oxygen generation

A novel upconversion nanoarchitecture is designed, whose 980 nm light photosensitized activity could be activated by 808 nm light.

The precise control of singlet oxygen (¹O₂) generation is in great demand for biological studies and precision medicine. Here, a nanoarchitecture is designed and synthesized for generating ¹O₂ in a dual NIR light-programmable manner, while shifting to the therapeutic window. The nanoarchitecture is constructed by controlled synthesis of mesoporous silica-coated upconversion nanoparticles (UCNPs), wherein the porphyrin photosensitizers (PSs) are covalently embedded inside the silica walls while NIR (808 nm)-responsive diarylethene (DAE) photochromic switches are loaded in the nanopores. Upon irradiation with 980 nm NIR light, the UCNP core absorbs low energy photons and transfers energy to the PSs in the silica wall, leading to efficient ¹O₂ generation. Furthermore, this 980 nm NIR light photosensitized activity can be remotely controlled by irradiation with a distinct NIR wavelength (808 nm). The ¹O₂ generation is inhibited when the DAE installed in the nanopores is in the closed form, whereas irradiation of the nanoconstruct with 808 NIR light leads to the transformation of DAE to the open form, and thus enabling full recovery of the 980 nm NIR light excited ¹O₂ generation capability. The NIR light-mediated on-demand “activation” of the nanoarchitecture for bioimaging and controllable photodynamic therapy is further demonstrated in vitro and in vivo.

Recent Progress on Near-Infrared Photoacoustic Imaging: Imaging Modality and Organic Semiconducting Agents

Over the past few decades, the photoacoustic (PA) effect has been widely investigated, opening up diverse applications, such as photoacoustic spectroscopy, estimation of chemical energies, or point-of-care detection. Notably, photoacoustic imaging (PAI) has also been developed and has recently received considerable attention in bio-related or clinical imaging fields, as it now facilitates an imaging platform in the near-infrared (NIR) region by taking advantage of the significant advancement of exogenous imaging agents. The NIR PAI platform now paves the way for high-resolution, deep-tissue imaging, which is imperative for contemporary theragnosis, a combination of precise diagnosis and well-timed therapy. This review reports the recent progress on NIR PAI modality, as well as semiconducting contrast agents, and outlines the trend in current NIR imaging and provides further direction for the prospective development of PAI systems.

A mitochondria-targeting dinuclear Ir-Ru complex as a synergistic photoactivated chemotherapy and photodynamic therapy agent against cisplatin-resistant tumour cells

A mitochondria-targeting hetero-binuclear Ir(iii)-Ru(ii) complex was developed as a photoactivated chemotherapy (PACT) and photodynamic therapy (PDT) bifunctional agent to achieve a synergistic effective therapeutic outcome for the therapy of cisplatin-resistant tumour cells.

PEGylated Tantalum Nanoparticles: A Metallic Photoacoustic Contrast Agent for Multiwavelength Imaging of Tumors

Elemental tantalum is a well-known biomedical metal in clinics due to its extremely high biocompatibility, which is superior to that of other biomedical metallic materials. Hence, it is of significance to expand the scope of biomedical applications of tantalum. Herein, it is reported that tantalum nanoparticles (Ta NPs), upon surface modification with polyethylene glycol (PEG) molecules via a silane-coupling approach, are employed as a metallic photoacoustic (PA) contrast agent for multiwavelength imaging of tumors. By virtue of the broad optical absorbance from the visible to near-infrared region and high photothermal conversion efficiency (27.9%), PEGylated Ta NPs depict high multiwavelength contrast capability for enhancing PA imaging to satisfy the various demands (penetration depth, background noise, etc.) of clinical diagnosis as needed. Particularly, the PA intensity of the tumor region postinjection is greatly increased by 4.87, 7.47, and 6.87-fold than that of preinjection under 680, 808, and 970 nm laser irradiation, respectively. In addition, Ta NPs with negligible cytotoxicity are capable of eliminating undesirable reactive oxygen species, ensuring the safety for biomedical applications. This work introduces a silane-coupling strategy for the surface engineering of Ta NPs, and highlights the potential of Ta NPs as a biocompatible metallic contrast agent for multiwavelength photoacoustic image.

Rational design of a multifunctional molecular dye for dual-modal NIR-II/photoacoustic imaging and photothermal therapy

Small-molecule based multifunctional probes play significant roles in biomedical science and possess high clinical translational ability. However, the preparation of these promising probes without complicated synthetic procedures remains a challenging task. Herein, we rationally designed a high-performance DD-A-DD scaffold molecular dye (SYL) with an intrinsic multifunctional ability and then incorporated it into DSPE-mPEG5000 to facilely construct biocompatible NIR-II fluorescent and photoacoustic (PA) dual-modal theranostic nanoprobes (SYL NPs) (∼120 nm). In vivo studies confirmed that SYL NPs exhibited bright NIR-II fluorescence and PA signals in the tumor region with a promising signal to background ratio (S/B). Meanwhile, SYL NPs demonstrated significantly inhibited tumor growth under laser irradiation with no noticeable side effects. These promising results highlighted SYL NPs as a potential theranostic platform for cancer diagnosis (NIR-II region) and therapy.

TMTP1-modified Indocyanine Green-loaded Polymeric Micelles for Targeted Imaging of Cervical Cancer and Metastasis Sentinel Lymph Node in vivo

Metastasis is one of the most threatening aspects of cervical cancer. We developed a method to intraoperatively map the primary tumor, metastasis and metastatic sentinel lymph nodes (SLNs), providing real-time intraoperative guidance in cervical cancer.

Methods: TMTP1, a tumor metastasis targeting peptide, was employed to modify the indocyanine green (ICG)-loaded poly (ethylene glycol)- poly (lactic-co-glycolic acid) (PEG-PLGA) micelles. The cervical cancer subcutaneous tumor model and lung metastasis model were established to determine the active targeting of ICG-loaded TMTP1-PEG-PLGA micelles (ITM) for the primary tumor and occult metastasis of cervical cancer. Human cervical cancer HeLa cells engineered by firefly luciferase were injected into the right hocks of BALB/c nude mice to develop the SLN metastasis model. The ITM and control ICG-loaded PEG-PLGA micelles (IM) were injected into the right hind footpads in the SLN metastasis model, and the migration and retention of micelles were recorded under near-infrared fluorescence. K14-HPV16 transgenic mice were also used to detect the image capability of ITM to target cancerous lesions.

Results: ITM could actively target imaging of the primary tumor and cervical cancer metastasis. ITM quickly diffused from the injection site to SLNs along lymphatic capillaries and remained in the SLNs for 12 h. Moreover, ITM specifically accumulated in the tumor metastatic SLNs (T-SLNs), which could be successfully distinguished from normal SLNs (N-SLNs).

Conclusion: ITM could achieve active targeting of the primary tumor, metastasis and T-SLNs, providing precise and real-time intraoperative guidance for cervical cancer.

Spatiotemporally Coupled Photoactivity of Phthalocyanine-Peptide Conjugate Self-Assemblies for Adaptive Tumor Theranostics

Spatiotemporally coupled tumor phototheranostic platforms offer a flexible and precise system that takes the biological interaction between tumors and photoactive agents into consideration for optimizing treatment, which is highly consistent with precision medicine. However, the fabrication of monocomponent-based photoactive agents applicable to multifold imaging techniques and multiple therapies in a facile way remains challenging. In this study, we developed simple phthalocyanine-peptide (PF) conjugate-based monocomponent nanoparticles with spatiotemporally coupled photoactivity for adaptive tumor theranostics. The self-assembled PF nanoparticles possess well-defined spherical nanostructures and excellent colloidal stability along with supramolecular photothermal effects. Importantly, the PF nanoparticles showed switchable photoactivity triggered by their interactions with the cell membrane, which enables an adaptive transformation from photothermal therapy (PTT) and photoacoustic imaging (PAI) to photodynamic therapy (PDT) and corresponding fluorescence imaging (FI). Theranostic modalities are integrated in a spatiotemporally coupled manner, providing a facile, biocompatible and effective route for localized tumor phototherapy. This study offers a flexible and versatile strategy to integrate multiple theranostic modalities into a single component so that it can realize its full potential and thereby amplify its therapeutic efficacy, creating promising opportunities for the design of theranostics and further highlighting their clinical prospects to the diagnosis and treatment of cancers.

Chemical Modulation of Bioengineered Exosomes for Tissue-Specific Biodistribution

The physicochemical properties of nanomaterials play a key role in tissue-specific targeting by reducing nonspecific background uptake as well as controlling biodistribution and clearance. Due to the strong influence of surface chemistry, chemical modulation of bioinert exosomes with chargeable and traceable small molecule fluorophores has a significant effect on the targeting, stability, and toxicity of the final conjugates. In this study, charge-variable exosomes are designed by conjugating their surface proteins with near-infrared fluorophores to control the in vivo fate of exosomes. Interestingly, zwitterionic fluorophore-labeled exosomes show rapid renal clearance with minimum to none nonspecific tissue uptake, whereas anionic exosomes are excreted through the hepatobiliary route with high uptake in the liver. The biodistribution and pharmacokinetics of exosome conjugates are comparable to their corresponding free fluorophores, demonstrating that the surface characteristics govern the fate of final conjugates in the living organism. Such unique surface properties of chemically modulated exosomes are confirmed in the lymphatic system after intradermal administration, which results in distinctive kinetic profiles in the secondary lymphoid tissues. This finding can subsequently serve as the foundation for developing tissue-specific exosome-based therapeutics.

Renal-clearable Molecular Semiconductor for Second Near-Infrared Fluorescence Imaging of Kidney Dysfunction

Real-time imaging of kidney function is important to assess the nephrotoxicity of drugs and monitor the progression of renal diseases; however, it remains challenging because of the lack of optical agents with high renal clearance and high signal-to-background ratio (SBR). Herein, a second near-infrared (NIR-II) fluorescent molecular semiconductor (CDIR2) is synthesized for real-time imaging of kidney dysfunction in living mice. CDIR2 not only has a high renal clearance efficiency (≈90 % injection dosage at 24 h post-injection), but also solely undergoes glomerular filtration into urine without being reabsorbed and secreted in renal tubules. Such a unidirectional renal clearance pathway of CDIR2 permits real-time monitoring of kidney dysfunction in living mice upon nephrotoxic exposure. Thus, this study not only introduces a molecular renal probe but also provides useful molecular guidelines to increase the renal clearance efficiency of NIR-II fluorescent agents.

A Novel Theranostic Nanoprobe for In Vivo Singlet Oxygen Detection and Real-Time Dose-Effect Relationship Monitoring in Photodynamic Therapy

Singlet oxygen, as the main member of reactive oxygen species, plays a significant role in cancer photodynamic therapy. However, the in vivo real-time detection of singlet oxygen remains challenging. In this work, a Förster resonance energy transfer (FRET)-based upconversion nanoplatform for monitoring the singlet oxygen in living systems is developed, with the ability to evaluate the in vivo dose-effect relationship between singlet oxygen and photodynamic therapy (PDT) efficacy. In details, this nanoplatform is composed of core-shell upconversion nanoparticles (UCNPs), photosensitizer MC540, NIR dye IR-820, and poly(acryl amine) PAA-octylamine, where the UCNPs serve as an energy donor while IR-820 serves as an energy acceptor. The nanoparticles are found to sensitively reflect the singlet oxygen levels generated in the tumor tissues during PDT, by luminescence intensity changes of UNCPs at 800 nm emission. Furthermore, it could also enable tumor treatment with satisfactory biocompatibility. To the best knowledge, this is the first report of a theranostic nanoplatform with the ability to formulate the in vivo dose-effect relationship between singlet oxygen and PDT efficacy and to achieve tumor treatment at the same time. This work might also provide an executable strategy to evaluate photodynamic therapeutic efficacy based on singlet oxygen pathway.

Photoacoustic Detection of Superoxide Using Oxoporphyrinogen and Porphyrin

The superoxide (O₂^•-) ion is a highly reactive oxygen species involved in many diseases; hence, its noninvasive detection is desirable to identify the onset of pathological processes. Here, we employed photoacoustic (PA) spectroscopy, which enables imaging at ultrasound resolution with the sensitivity of optical modality, for the first time to detect O₂^•-, using stimuli-responsive contrast agents. meso-(3,5-Di-tert-butyl 4-hydroxyphenyl) porphyrins and oxoporphyrinogens were used as PA contrast agents, which trap the O₂^•- and enable its detection. The trapped O₂^•- increased the PA signal amplitude of chromophores up to 9.6-fold, and induced a red-shift in the PA signal maxima of up to 225 nm. Therefore, these trigger-responsive probes may be highly valuable as smart diagnostic PA probes to investigate pathological events stimulated by O₂^•- species.

Single NIR Laser-Activated Multifunctional Nanoparticles for Cascaded Photothermal and Oxygen-Independent Photodynamic Therapy

Inconvenient dual-laser irradiation and tumor hypoxic environment as well as limited judgment of treating region have impeded the development of combined photothermal and photodynamic therapies (PTT and PDT). Herein, Bi₂Se₃@AIPH nanoparticles (NPs) are facilely developed to overcome these problems. Through a one-step method, free radical generator (AIPH) and phase transition material (lauric acid, LA, 44-46 °C) are encapsulated in hollow bismuth selenide nanoparticles (Bi₂Se₃ NPs). Under a single 808-nm laser irradiation at the tumor area, hyperthermia produced by Bi₂Se₃ not only directly leads to cell death, but also promotes AIPH release by melting LA and triggers free radical generation, which could further eradicate tumor cells in hypoxic environments. Moreover, Bi₂Se₃ with high X-ray attenuation coefficient endows the NPs with high computed tomography (CT) imaging capability, which is important for treating area determination. The results exhibit that Bi₂Se₃@AIPH NPs possesses 31.2% photothermal conversion efficiency for enhanced PTT, ideal free radical generation for oxygen-independent PDT, and 37.77 HU mL mg^-1 X-ray attenuation coefficient for CT imaging with high quality. Most importantly, the tumor growth inhibition rate by synergistic PTT, PDT, and following immunotherapy is 99.6%, and even one tumor disappears completely, which demonstrates excellent cascaded synergistic effect of Bi₂Se₃@AIPH NPs for the tumor therapy.

Synthesis of Bi2WO6-x nanodots with oxygen vacancies as an all-in-one nanoagent for simultaneous CT/IR imaging and photothermal/photodynamic therapy of tumors

All-in-one nanoagents with a single-component and all-required functions have attracted increasing attention for the imaging-guided therapy of tumors, but the design and preparation of such nanoagents remain a challenge. Herein, we report the introduction of oxygen vacancies to traditional semiconductors with heavy-metal elements for tuning photoabsorption in the near infrared (NIR) region, by using Bi2WO6 (band-gap: ∼2.7 eV) as a model. Bi2WO6-x nanodots with sizes of ∼3 or ∼8 nm have been prepared by a facile coprecipitation-solvothermal method assisted by citric acid (CA, 0.1-1.5 g) as the reduction agent. CA confers the removal of O atoms from the [Bi2O2]2+ layer during the solvothermal process, resulting in the formation of plenty of oxygen vacancies in the Bi2WO6-x crystal. As a result, NIR photoabsorption of Bi2WO6-x nanodots can be remarkably enhanced with the increase of the CA amount from 0 to 1.0 g. Under irradiation of a single-wavelength (808 nm, 1.0 W cm-2) NIR laser, black Bi2WO6-x-CA1.0 nanodots can not only efficiently produce a sufficient amount of heat with a photothermal conversion efficiency of 45.1% for photothermal therapy, but also generate singlet oxygen (1O2) for photodynamic therapy. Furthermore, due to the presence of heavy-metal (Bi and W) elements, Bi2WO6-x-CA1.0 nanodots have high X-ray attenuation ability for CT imaging. After the Bi2WO6-x-CA1.0 nanodot dispersion is injected into the tumor-bearing mice, the tumor can be imaged by using CT and an IR thermal camera. After irradiation with a single-wavelength (808 nm, 1.0 W cm-2, 10 min) NIR laser, the tumor can be completely suppressed by the synergic photothermal and photodynamic effects of Bi2WO6-x-CA1.0 nanodots, without recurrence and treatment-induced toxicity. Therefore, Bi2WO6-x nanodots have great potential as a novel all-in-one nanoagent for the imaging and phototherapy of tumors.

Ultrabright Fluorescent Polymer Dots with Thermochromic Characteristics for Full-Color Security Marking

Innovative and scalable security technologies are in high demand to deter increasing counterfeiting in modern society. Here, we report the first example of thermochromic-fluorescent ink based on semiconducting polymer dots (Pdots) by taking advantage of the unique optical properties of Pdots. We designed and synthesized two types of thermochromic molecules and then incorporated them with multicolor fluorescent Pdots. The resulting Pdots exhibited colorimetric and fluorescent dual-readout abilities in response to different temperatures which greatly increase the security level for anticounterfeiting applications. These multifunctional Pdots can be easily doped into flexible substrates or prepared as inks. These full-color inks can be further loaded into marker pens for handwriting or cartridges for inkjet printing with excellent signal-to-background contrast. Moreover, complex and delicate full-color images can be printed on security documents or currency for practical use. We anticipate that this first example of thermoresponsive dual-readout methodology based on Pdots will have broad use in advanced security marking technologies.

MnFe2O4-decorated large-pore mesoporous silica-coated upconversion nanoparticles for near-infrared light-induced and O2 self-sufficient photodynamic therapy

The limited light penetration depth and tumor hypoxia are two natural shortcomings of photodynamic therapy (PDT). Overcoming these two issues within a single system is still a great challenge. Herein, photosensitizer (PS)-loaded and PEG-modified MnFe2O4-decorated large-pore mesoporous silica-coated β-NaYF4:20%Yb,2%Er@β-NaYF4 upconversion nanoparticles (UCMnFe-PS-PEG) as excellent PDT agents are successfully prepared for NIR light-mediated and O2 self-sufficient PDT. The large mesoporous structure observably increases PS loading efficiency (11.33 wt%) and the green luminescence from upconversion nanoparticles activated by NIR is able to activate PSs to generate ROS effectively. In addition, sub-10 nm MnFe2O4 nanoparticles work as a Fenton catalyst to generate O2in situ. In vivo experiments further prove that UCMnFe-PS-PEG not only provides magnetic guidance to the tumor, but also overcomes tumor hypoxia and dramatically enhances PDT efficiency. Furthermore, in vivo MR and UCL imaging are performed for accurate cancer therapy. We believe that the successful construction of the multifunctional UCMnFe-PS-PEG provides more revelations for developing advanced nano-drug systems for cancer therapy.

High-Aspect-Ratio Semiconducting Polymer Pillars for 3D Cell Cultures

Hybrid interfaces between living cells and nano/microstructured scaffolds have huge application potential in biotechnology, spanning from regenerative medicine and stem cell therapies to localized drug delivery and from biosensing and tissue engineering to neural computing. However, 3D architectures based on semiconducting polymers, endowed with responsivity to visible light, have never been considered. Here, we apply for the first time a push-coating technique to realize high aspect ratio polymeric pillars, based on polythiophene, showing optimal biocompatibility and allowing for the realization of soft, 3D cell cultures of both primary neurons and cell line models. HEK-293 cells cultured on top of polymer pillars display a remarkable change in the cell morphology and a sizable enhancement of the membrane capacitance due to the cell membrane thinning in correspondence to the pillars' top surface, without negatively affecting cell proliferation. Electrophysiology properties and synapse number of primary neurons are also very well preserved. In perspective, high aspect ratio semiconducting polymer pillars may find interesting applications as soft, photoactive elements for cell activity sensing and modulation.

A nano-cocktail of an NIR-II emissive fluorophore and organoplatinum(ii) metallacycle for efficient cancer imaging and therapy

The scarcity of efficient imaging technologies for precise cancer treatment greatly drives the development of new nanotheranostic based platforms that enable both diagnostic and therapeutic functions, together in a single formulation. Owing to the complicated physiological microenvironment, nanosystems designed with the possibility of noninvasive real-time monitoring of therapeutic progression in the second near-infrared channel (NIR-II, 1000-1700 nm) could substantially improve the current cancer therapies. Herein, we design a novel NIR-II theranostic nanoprobe, PSY (size ∼110 nm), by incorporating organoplatinum(ii) metallacycles P1 and an organic NIR-II molecular dye, SY1030, into the FDA-approved polymer Pluronic F127. Preliminary in vitro and in vivo studies suggest that PSY is capable of being internalized into glioma U87MG-cells with no significant internalization in non-cancerous tissues. In addition, it shows excellent photostability and minimal background for real-time monitoring the process of therapy in the NIR-II region. Furthermore, in U87MG xenografts and orthotopic breast tumor, PSY demonstrat significantly improved anticancer efficacy compared to a clinically approved Pt(ii)-based anticancer drug, cisplatin. The engineered nano-cocktail PSY offers a simple strategy for delivering the organoplatinum(ii) macrocycle P1 and NIR-II fluorophore SY1030 as a cocktail of diagnostic and therapeutic functions and highlights its promising capacity for future cancer treatment.

A dual-targeted theranostic photosensitizer based on a TADF fluorescein derivative

Specific diagnosis and therapy of cancer is still a challenge in biomedical research. Photodynamic therapy (PDT) has emerged as a novel therapeutic modality for cancer treatment. However, the traditional PDT photosensitizers often exhibit low specific selectivity. In this study, we have reported a dual-targeted theranostic photosensitizer FL-RGD by covalently conjugating tumor marker cyclic arginine-glycine-aspartic acid tripeptide (RGD) and a fluorescein derivative FL which has a property of thermally activated delayed fluorescence (TADF) and a long triplet lifetime for efficient PDT. The FL-RGD can target tumor tissues and further locate lysosomes of tumor cells to concurrently achieve the cancers' specific diagnosis and efficient treatment. The mechanism of its highly efficient PDT was attributed to the damage of lysosome via ¹O₂. Besides, FL-RGD has the potential to be utilized in depth imaging and treatment by two-photon excitation. The actual diagnosis performance of FL-RGD was proved by fluorescence imaging of living cells and tumor bearing mice. The therapy performance was proved by MTT assays, fluorescence-activated cell sorting (FACS) analysis and PDT experiments on tumor bearing mice. The research obviously exhibited the potential of FL-RGD for tumor theranostics in vivo and in vitro.

Nanotransducers for Near-Infrared Photoregulation in Biomedicine

Photoregulation, which utilizes light to remotely control biological events, provides a precise way to decipher biology and innovate in medicine; however, its potential is limited by the shallow tissue penetration and/or phototoxicity of ultraviolet (UV)/visible light that are required to match the optical responses of endogenous photosensitive substances. Thereby, biologically friendly near-infrared (NIR) light with improved tissue penetration is desired for photoregulation. Since there are a few endogenous biomolecules absorbing or emitting light in the NIR region, the development of molecular transducers is essential to convert NIR light into the cues for regulation of biological events. In this regard, optical nanomaterials able to convert NIR light into UV/visible light, heat, or free radicals are suitable for this task. Here, the recent developments of optical nanotransducers for NIR-light-mediated photoregulation in medicine are summarized. The emerging applications, including photoregulation of neural activity, gene expression, and visual systems, as well as photochemical tissue bonding, are highlighted, along with the design principles of nanotransducers. Moreover, the current challenges and perspectives in this field are discussed.

Copper Sulfide Nanodisks and Nanoprisms for Photoacoustic Ovarian Tumor Imaging

Transvaginal ultrasound is widely used for ovarian cancer screening but has a high false positive rate. Photoacoustic imaging provides additional optical contrast to supplement ultrasound and might be able to improve the accuracy of screening. Here, we report two copper sulfide (CuS) nanoparticles types (nanodisks and triangular nanoprisms) as the photoacoustic contrast agents for imaging ovarian cancer. Both CuS nanoprisms and nanodisks were ~6 nm thick and ~26 nm wide and were coated with poly(ethylene glycol) to make them colloidally stable in phosphate buffered saline (PBS) for at least 2 weeks. The CuS nanodisks and nanoprisms revealed strong localized surface plasmon resonances with peak maxima at 1145 nm and 1098 nm, respectively. Both nanoparticles types had strong and stable photoacoustic intensity with detection limits below 120 pM. The circular CuS nanodisk remained in the circulation of nude mice (n=4) and xenograft 2008 ovarian tumors (n=4) 17.9-fold and 1.8-fold more than the triangular nanoprisms, respectively. Finally, the photoacoustic intensity of the tumors from the mice (n=3) treated with CuS nanodisks was 3.0-fold higher than the baseline. The tumors treated with nanodisks had a characteristic peak at 920 nm in the spectrum to potentially differentiate the tumor from adjacent tissues.

An Organic Afterglow Protheranostic Nanoassembly

Cancer theranostics holds potential promise for precision medicine; however, most existing theranostic nanoagents are simply developed by doping both therapeutic agents and imaging agent into one particle entity, and thus have an "always-on" pharmaceutical effect and imaging signals regardless of their in vivo location. Herein, the development of an organic afterglow protheranostic nanoassembly (APtN) that specifically activates both the pharmaceutical effect and diagnostic signals in response to a tumor-associated chemical mediator (hydrogen peroxide, H₂ O₂ ) is reported. APtN comprises an amphiphilic macromolecule and a near-infrared (NIR) dye acting as the H₂ O₂ -responsive afterglow prodrug and the afterglow initiator, respectively. Such a molecular architecture allows APtN to passively target tumors in living mice, specifically release the anticancer drug in the tumor, and spontaneously generate the uncaged afterglow substrate. Upon NIR light preirradiation, the afterglow initiator generates singlet oxygen to react and subsequently transform the uncaged afterglow substrate into an active self-luminescent form. Thus, the intensity of generated afterglow luminescence is correlated with the drug release status, permitting real-time in vivo monitoring of prodrug activation. This study proposes a background-free design strategy toward activatable cancer theranostics.

Organic Semiconducting Pro-nanostimulants for Near-Infrared Photoactivatable Cancer Immunotherapy

In this study, an organic semiconducting pro-nanostimulant (OSPS) with a near-infrared (NIR) photoactivatable immunotherapeutic action for synergetic cancer therapy is presented. OSPS comprises a semiconducting polymer nanoparticle (SPN) core and an immunostimulant conjugated through a singlet oxygen (¹ O₂ ) cleavable linkers. Upon NIR laser irradiation, OSPS generates both heat and ¹ O₂ to exert combinational phototherapy not only to ablate tumors but also to produce tumor-associated antigens. More importantly, NIR irradiation triggers the cleavage of ¹ O₂ -cleavable linkers, triggering the remote release of the immunostimulants from OSPS to modulate the immunosuppressive tumor microenvironment. Thus, the released tumor-associated antigens in conjunction with activated immunostimulants induce a synergistic antitumor immune response after OSPS-mediated phototherapy, resulting in the inhibited growth of both primary/distant tumors and lung metastasis in a mouse xenograft model, which is not observed for sole phototherapy.

A Magneto-Optical Nanoplatform for Multimodality Imaging of Tumors in Mice

Multimodality imaging involves the use of more imaging modes to image the same living subjects and is now generally preferred in clinics for cancer imaging. Here we present multimodality-Magnetic Particle Imaging (MPI), Magnetic Resonance Imaging (MRI), Photoacoustic, Fluorescent-nanoparticles (termed MMPF NPs) for imaging tumor xenografts in living mice. MMPF NPs provide long-term (more than 2 months), dynamic, and accurate quantification, in vivo, of NPs and in real time by MPI. Moreover, MMPF NPs offer ultrasensitive MPI imaging of tumors (the tumor ROI increased by 30.6 times over that of preinjection). Moreover, the nanoparticle possessed a long-term blood circulation time (half-life at 49 h) and high tumor uptake (18% ID/g). MMPF NPs have been demonstrated for imaging breast and brain tumor xenografts in both subcutaneous and orthotopic models in mice via simultaneous MPI, MRI, fluorescence, and photoacoustic imaging with excellent tumor contrast to normal tissues.

Tumor-Microenvironment-Induced All-in-One Nanoplatform for Multimodal Imaging-Guided Chemical and Photothermal Therapy of Cancer

Precisely locating tumor site based on tumor-microenvironment-induced (TMI) multimodal imaging is especially interesting for accurate and efficient cancer therapy. In the present investigation, a novel TMI all-in-one nanoplatform, CuS_NC@DOX@MnO_2-NS, has been successfully fabricated for chemical and photothermal (Chem-PTT) therapy guided by multimodal imaging on tumor site. Here, the CuS nanocages with mesoporous and hollow structure (CuS_NC) acting as nanocarriers provide high capacity for loading the anticancer drug, doxorubicin (DOX). The outer layer of the MnO₂ nanoshell (MnO_2-NS) acts as "gatekeeper" to control the DOX release until the nanoplatform arrives at the tumor site, where abundant glutathione and H⁺ decompose MnO_2-NS into paramagnetic Mn²⁺. The magnetic resonance imaging and fluorescent imaging were then triggered to locate the tumor, which was further improved by photothermal imaging on account of the intrinsic property of CuS_NC. Guided by the multimode imaging, the combination of chemical therapy upon DOX and photothermal therapy upon CuS_NC exhibits eminent efficiency on tumor ablation. The nanoplatform exhibits biocompatibility to avoid unwanted harm to normal tissues during trans-shipment in the body. The investigation thus develops a cost-effective TMI nanoplatform with facile preparations and easy integration of Chem-PTT treatment capabilities guided by multimodal imaging for potential application in precise therapy.

Mutualistic benefit in the self-sorted co-aggregates of peri-naphthoindigo and a 4-amino-1,8-naphthalimide derivative

Photoluminescence enhancement for all the members of a self-sorted co-aggregate was observed for the first time by successfully amalgamating AIEE and social self-sorting. Intermolecular H-bonding and π-π stacking were utilised to prepare several co-aggregates of peri-naphthoindigo (PNI) and a 4-amino-1,8-naphthalimide derivative dye, NH₂-NMI. In the heteromeric aggregates, photoluminescence intensities were increased by 28% for the imide and more than 400% for PNI. Due to spectral overlap between the emission of the imide and the absorption of PNI, energy transfer took place from the former to the latter. The heteromeric aggregates are dual emissive and the relative intensities of the emissions can easily be tuned by varying the stoichiometry of the dyes.

Platelet-membrane-camouflaged bismuth sulfide nanorods for synergistic radio-photothermal therapy against cancer

Bismuth-containing nanoparticles (BNPs) are potential enhancers for tumor radiotherapy. Improving the bioavailability and developing synergistic therapeutic regimens benefit the drug transformation of BNPs. In the present study, we prepare a mesoporous silica-coated bismuth nanorod (BMSNR) camouflaged by a platelet membrane (PM). This biomimetic material is termed BMSNR@PM. The PM camouflage enhances the immune escape of the BMSNRs by lowering endocytosis by macrophages in the reticuloendothelial system. Additionally, the PM camouflage strengthens the material tumor-targeting capacity and leads to better radiotherapeutic efficacy compared with bare BMSNRs. Owing to the photothermal effect, BMSNR@PMs alters the cell cycle of 4T1 cancer cells post-treatment with 808 nm near-infrared irradiation (NIR). The proportions of S phase and G2/M phase cells decrease and increase, respectively, which explains the synergistic effect of NIR on BMSNR@PM-based radiotherapy. BMSNR@PMs efficiently eradicates cancer cells by the combined action of photothermal therapy (PTT) and radiotherapy in vivo and markedly improves the survival of 4T1-tumor-bearing mice. The synergistic therapeutic effect is superior to the outcomes of PTT and radiotherapy performed alone. Our study demonstrates a versatile bismuth-containing nanoplatform with tumor-targeting, immune escape, and radiosensitizing functionalities using an autologous cell membrane biomimetic concept that may promote the development of radiotherapy enhancers.

Near-Infrared Light Activated Thermosensitive Ion Channel to Remotely Control Transgene System for Thrombolysis Therapy

Current antithrombotic therapeutic strategies often suffer from severe post-thrombotic syndromes (PTS), inconvenient daily subcutaneous injections for a long time and short circulation times accompanied by a dose-dependent risk of intracranial hemorrhage. Aiming at noninvasive, on-demand, and sustained antithrombotic therapy, a new thrombolysis approach based on the transgene system has been developed to remotely and precisely control the expression of urokinase plasminogen activator (uPA) by bioengineered cells for antithrombotic therapy both in vitro and in vivo. In this design, the near-infrared (NIR) light could activate the expression of the thermosensitive TRPV1 channel in response to photothermal responsive nanotransducers to trigger the synthetic signaling pathway to secret uPA. By encapsulating bioengineered cells in injectable hydrogel to ensure long-term survival and convenience for injection, the engineered cells could noninvasively and precisely control the production of uPA protein in situ via an NIR laser to significantly enhance the thrombolysis therapeutic effects by spatiotemporally controlling the local temperature, in both the microfluidic blood circulation mimic and the murine tail thrombus model. This novel thrombolysis approach could overcome some key limitations that are associated with conventional antithrombotic therapy, thus opening a new direction for developing remotely and precisely controllable continuous thrombolysis through artificially designed signaling.

Synthesis and biological evaluation of an epidermal growth factor receptor-targeted peptide-conjugated phthalocyanine-based photosensitiser

A peptide-conjugated zinc(ii) phthalocyanine containing the epidermal growth factor receptor-targeted heptapeptide QRHKPRE has been prepared. The conjugate labelled as ZnPc-QRH* can selectively bind to the cell membrane of HT29 human colorectal adenocarcinoma cells in 10 min followed by internalisation upon prolonged incubation via receptor-mediated endocytosis, leading to localisation in lysosomes eventually. By manipulating the incubation time, the subcellular localisation of the conjugate can be varied and the cell-death pathways induced upon irradiation can also be altered. It has been found that photosensitisation initiated at the cell membrane and in the lysosomes would trigger cell death mainly through necrosis and apoptosis respectively. Intravenous administration of the conjugate into HT29 tumour-bearing nude mice resulted in higher accumulation in the tumour than in most major organs. The selective binding of this conjugate to tumour has also been demonstrated by comparing the results with those of the analogue with a scrambled peptide sequence (EPRQRHK). The overall results indicate that ZnPc-QRH* is a promising EGFR-targeted photosensitiser for photodynamic therapy.

Beyond 1000 nm Emission Wavelength: Recent Advances in Organic and Inorganic Emitters for Deep-Tissue Molecular Imaging

In vivo second near-infrared (NIR-II, 1.0-1.7 µm) bioimaging , a rapidly expanding imaging tool for preclinical diagnosis and prognosis, is of great importance to afford precise dynamic actions in vivo with high spatiotemporal resolution, deeper penetration, and decreasing light absorption and scattering. In the course of preclinical practices, organic and inorganic emitters with NIR-II signals are indispensable keys to open the invisible biological window. In this review, NIR-II emitters, including but not limited to organic emitters like organic small molecules and copolymers, and inorganic emitters such as lanthanide-based nanocrystals, quantum dots like Ag₂ S dots, and carbon nanotubes, are described, especially regarding their unique optical features and noteworthy functions for animal bioimaging. Along with these existing advances, the challenges and potential spaces for further progress are discussed to offer an approximate direction for future researches.

Highly Stable Core-Shell Structured Semiconducting Polymer Nanoparticles for FRET-Based Intracellular pH Imaging

Highly stable semiconducting polymer nanoparticles (NPs) (poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO)/ poly(fluorene-2,7-ylenevinylene-co-phenylene) (PFV)-dopamine (DA) NPs) with previously unreported core-shell structure are developed for ratiometric sensing of intracellular pH values. PFO/PFV-DA NPs comprise central polyfluorene (PFO) as donor and PFV as acceptor, in which the donor and acceptor are spatially separated into the central core and nanoparticle shell. Specifically, thick PFV shells can not only significantly minimize the quenching interference of dopamine on the emission of standard reference (PFO), but are also able to maximize its accessibility to pH-sensitive dopamine and lead to sensitive response to pH changes. The resulting core-shell PFO/PFV NPs are structurally and optically stable, which can avoid the photobleaching and leakage of materials issues compared to traditional semiconducting polymer nanoparticles (SPNs)-based fluorescence resonance energy transfer (FRET) systems containing small molecules. Additionally, the designed compact PFO/PFV-DA NPs show quantitative response to the pH values in aqueous media and are capable of mapping intracellular pH fluctuations by ratiometric imaging. This work may open up opportunities for the generalizability of the consistent ratiometric emission intensity strategy based on core-shell structured SPNs nanoprobes for highly sensitive biological sensing.