One-pot synthesis of albumin-gadolinium stabilized polypyrrole nanotheranostic agent for magnetic resonance imaging guided photothermal therapy

A Biomineralized Bifunctional Patient-Friendly Nanosystem for Sustained Glucose Monitoring and Control in Diabetes

Regular blood glucose monitoring and control is necessary for people with type 1 or advanced type 2 diabetes, yet diagnosing and treating patients with diabetes in an accurate, sustained and patient-friendly manner remains limited. Here, a glucose-responsive bifunctional nanosystem (PGOxMns) is constructed via one-pot biomineralisation of manganese dioxide with glucose oxidase and ε-poly-L-lysine. Under hyperglycaemic conditions, the cascade reactions that occur when glucose interacts with PGOxMns can trigger the production of Mn(II), which enhances the magnetic resonance imaging signal. Simultaneously, manganese dioxide catalyses the decomposition of toxic hydrogen peroxide into oxygen, which also maintains glucose oxidase (GOx) activity. In an in vivo model of diabetes, PGOxMns is used to monitor glucose levels (0-20 mm) and allowed identification of diabetic mice via T1-weighted MRI. Furthermore, PGOxMns is found to have a high insulin-loading capacity (83.6%), likely due to its positive charge. A single subcutaneous injection of insulin-loaded nanosystem (Ins-PGOxMns) into diabetic mice resulted in a rapid and efficient response to a glucose challenge and prolonged blood glucose level control (< 200 mg dL-1) for up to 50 h. Overall, this proof-of-concept study demonstrates the feasibility of using biomineralised nanosystems to develop patient-friendly strategies for glucose monitoring and control.

Intelligent gold nanocluster for effective treatment of malignant tumor via tumor-specific photothermal-chemodynamic therapy with AIE guidance

Precise and efficient therapy of malignant tumors is always a challenge. Herein, gold nanoclusters co-modified by aggregation-induced-emission (AIE) molecules, copper ion chelator (acylthiourea) and tumor-targeting agent (folic acid) were fabricated to perform AIE-guided and tumor-specific synergistic therapy with great spatio-temporal controllability for the targeted elimination and metastasis inhibition of malignant tumors. During therapy, the functional gold nanoclusters (AuNTF) would rapidly accumulate in the tumor tissue due to the enhanced permeability and retention effect as well as folic acid-mediated tumor targeting, which was followed by endocytosis by tumor cells. After that, the overexpressed copper ions in the tumor cells would trigger the aggregation of these intracellular AuNTF via a chelation process that not only generated the photothermal agent in situ to perform the tumor-specific photothermal therapy damaging the primary tumor, but also led to the copper deficiency of tumor cells to inhibit its metastasis. Moreover, the copper ions were reduced to cuprous ions along with the chelation, which further catalysed the excess H2O2 in the tumor cells to produce cytotoxic reactive oxygen species, resulting in additional chemodynamic therapy for enhanced antitumor efficiency. The aggregation of AuNTF also activated the AIE molecules to present fluorescence, which not only imaged the therapeutic area for real-time monitoring of this tumor-specific synergistic therapy, but also allowed us to perform near-infrared radiation at the correct time point and location to achieve optimal photothermal therapy. Both in vitro and in vivo results revealed the strong tumor elimination, effective metastasis inhibition and high survival rate of tumor-bearing mice after treatment using the AuNTF nanoclusters, indicating that this AIE-guided and tumor-specific synergistic strategy could offer a promising approach for tumor therapy.

Bioinspired Multiscale Mineralization: From Fundamentals to Potential Applications

The wondrous and imaginative designs of nature have always been an inexhaustible treasure trove for material scientists. Throughout the long evolutionary process, biominerals with hierarchical structures possess some specific advantages such as outstanding mechanical properties, biological functions, and sensing performances, the formation of which (biomineralization) is delicately regulated by organic component. Provoked by the subtle structures and profound principles of nature, bioinspired functional minerals can be designed with the participation of organic molecules. Because of the designable morphology and functions, multiscale mineralization has attracted more and more attention in the areas of medicine, chemistry, biology, and material science. This review provides a summary of current advancements in this extending topic. The mechanisms underlying mineralization is first concisely elucidated. Next, several types of minerals are categorized according to their structural characteristic, as well as the different potential applications of these materials. At last, a comprehensive overview of future developments for bioinspired multiscale mineralization is given. Concentrating on the mechanism of fabrication and broad application prospects of multiscale mineralization, the hope is to provide inspirations for the design of other functional materials.

PtSnBi Nanoplates Enable Photoacoustic Imaging-Guided Highly Efficient Photothermal Tumor Ablation

The development of photothermal agents (PTAs) with robust photostability and high photothermal conversion efficiency is of great importance for cancer photothermal therapy. Herein, a novel PTA was created using two-dimensional intermetallic PtSnBi nanoplates (NPs), which demonstrated excellent photostability and biocompatibility with a high photothermal conversion efficiency of ∼61 % after PEGylation. More importantly, PtSnBi NPs could be employed as photoacoustic imaging contrast agents for tumor visualization due to their strong absorbance in the NIR range. In addition, both in vitro and in vivo experiments confirmed that PtSnBi NPs had a good photothermal efficacy under NIR laser irradiation. Therefore, the remarkable therapeutic characteristics of PtSnBi NPs make them a most promising candidate for cancer theranostics.

Intelligent Bi2Se3@Cu2-xSe heterostructures with enhanced photoabsorption and photoconversion efficiency for tri-modal imaging guided combinatorial cancer therapy by near-infrared Ⅱ light

A novel nanoplatform that supports multimodal imaging has been designed for deep tumor therapy. In this study, Bi₂Se₃@Cu_2-xSe heterojunction nanocomposites with tunable spectral absorption, effective electron-hole separation and high photothermal conversion efficiency were prepared for the combination therapy of phototherapy (PT), chemodynamic therapy (CDT) and radiotherapy (RT). By adjusting the doping ratio, the heterojunction nanoparticles show obvious tunable ability of local surface plasmon resonance and the ability to promote electron-hole separation with significantly enhanced reactive oxygen species production capacity. The band structure and charge density difference calculated by density functional theory further reveal that the change of band gap and the decrease of free carriers can regulate the spectral absorption of nanomaterials and promote electron-hole separation. In addition, the photothermal conversion properties of low carrier density semiconductors are related to their inherent deep level defects. The formation of heterojunctions making the Se atoms deviate from the Bi₂Se₃ lattice, resulting in more deep level defects and stronger photothermal conversion properties. Meanwhile, this nanoplatform presented features similar to catalase activities and glutathione (GSH) consumption characteristics, which was capable of effectively alleviate the tumor-specific hypoxia environment to enhance the efficacy of O₂-dependent photodynamic therapy (PDT) and radiotherapy (RT) and depletion GSH to prevent the reduction of therapeutic efficacy due to the clearance of reactive oxygen species. In addition to therapeutic enhancement, heterojunction nanomaterials have excellent nuclear magnetic resonance imaging (MRI), infrared thermal imaging (IR) and computed tomography (CT) properties due to their significant paramagnetism and excellent photothermal conversion and X-ray attenuation capacities. In conclusion, our findings provide a new strategy for designing multi-function and efficient nanoplatform to treat tumor.

Molybdenum blue mediated photothermal immunoassay for CEA detection based on Ag4P2O7@Ag nanocomposites

A photothermal immunoassay was built for tumor marker detection based on Ag₄P₂O₇@Ag nanocomposites. Ag₄P₂O₇@Ag nanomaterials were synthesized by precipitation-photoreduction reaction, and characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectra (XPS) and X-ray powder diffraction (XRD). Come about PO₄^3- derived from Ag₄P₂O₇@Ag under acidic conditions react with ammonium molybdate in the action of reductant generating molybdenum blue. The photothermal change is due to molybdenum blue solution depending on the concentration of carcinoembryonic antigen (CEA) in immunoassay. Under optimal conditions, there is a linear relation between ΔT and CEA concentration in the range of 1 pg mL^-1-40 ng mL^-1 with the detection limit of 0.33 pg mL^-1. Meanwhile, the developed photothermal immunoassay displays preferable selectivity, repeatability, and stability.

Nanostructured particles assembled from natural building blocks for advanced therapies

Advanced treatments based on immune system manipulation, gene transcription and regulation, specific organ and cell targeting, and/or photon energy conversion have emerged as promising therapeutic strategies against a range of challenging diseases. Naturally derived macromolecules (e.g., proteins, lipids, polysaccharides, and polyphenols) have increasingly found use as fundamental building blocks for nanostructured particles as their advantageous properties, including biocompatibility, biodegradability, inherent bioactivity, and diverse chemical properties make them suitable for advanced therapeutic applications. This review provides a timely and comprehensive summary of the use of a broad range of natural building blocks in the rapidly developing field of advanced therapeutics with insights specific to nanostructured particles. We focus on an up-to-date overview of the assembly of nanostructured particles using natural building blocks and summarize their key scientific and preclinical milestones for advanced therapies, including adoptive cell therapy, immunotherapy, gene therapy, active targeted drug delivery, photoacoustic therapy and imaging, photothermal therapy, and combinational therapy. A cross-comparison of the advantages and disadvantages of different natural building blocks are highlighted to elucidate the key design principles for such bio-derived nanoparticles toward improving their performance and adoption. Current challenges and future research directions are also discussed, which will accelerate our understanding of designing, engineering, and applying nanostructured particles for advanced therapies.

Polypyrrole-based nanotheranostic agent for MRI guided photothermal-chemodynamic synergistic cancer therapy

Polypyrrole (PPy) nanoparticles have been widely studied in tumor photothermal therapy (PTT) for their significant photostability, good biocompatibility, and excellent photothermal performance. Herein, we report bovine serum albumin (BSA) stabilized PPy that were mineralized by MnO₂ nanozyme on the surface (PPy@BSA-MnO₂) to achieve synergistic photothermal and chemodynamic therapy (CDT) for breast cancer. In this multifunctional nanoplatform, the surface-loaded MnO₂ undergoes a redox reaction with glutathione (GSH) to generate glutathione disulfide (GSSG) and Mn²⁺. Then, Mn²⁺ can convert H₂O₂ into a highly cytotoxic ˙OH to achieve chemodynamic therapy (CDT) and possess good magnetic resonance (MR) T₁-weighted imaging capabilities to realize contrast imaging of the 4T1 tumor-bearing mouse models. In addition, PPy nanoparticles can efficiently convert near-infrared light energy into heat and achieve PTT. Most importantly, PPy@BSA-MnO₂ nanoprobes have excellent in vitro 4T1 cell-killing effect and in vivo tumor-suppressive properties. The acute toxicity assessment results indicate that PPy@BSA-MnO₂ nanoprobes have good biological safety. Therefore, the as-prepared multifunctional PPy@BSA-MnO₂ nanoprobes possess excellent performance to promote MRI-guided PTT/CDT synergistic therapy for breast cancer treatment and have extensive clinical transformation and application prospects.

Dual Tumor Microenvironment Remodeling by Glucose-Contained Radical Copolymer for MRI-Guided Photoimmunotherapy

Aberrant glucose metabolism and immune evasion are recognized as two hallmarks of cancer, which contribute to poor treatment efficiency and tumor progression. Herein, a novel material system consisting of a glucose and TEMPO (2,2,6,6-tetramethylpiperidin-1-yl)oxyl) at the distal ends of PEO-b-PLLA block copolymer (glucose-PEO-b-PLLA-TEMPO), is designed to encapsulate clinical therapeutics CUDC101 and photosensitizer IR780. The specific core-shell rod structure formed by the designed copolymer renders TEMPO radicals excellent stability against reduction-induced magnetic resonance imaging (MRI) silence. Tumor-targeting moiety endowed by glucose provides the radical copolymer outstanding multimodal imaging capabilities, including MRI, photoacoustic imaging, and fluorescence imaging. Efficient delivery of CUDC101 and IR780 is achieved to synergize the antitumor immune activation through IR780-mediated photodynamic therapy (PDT) and CUDC101-triggered CD47 inhibition, showing M1 phenotype polarization of tumor-associated macrophages (TAMs). More intriguingly, this study demonstrates PDT-stimulated p53 can also re-educate TAMs, providing a combined strategy of using dual tumor microenvironment remodeling to achieve the synergistic effect in the transition from cold immunosuppressive to hot immunoresponsive tumor microenvironment.

Development of copper vacancy defects in a silver-doped CuS nanoplatform for high-efficiency photothermal-chemodynamic synergistic antitumor therapy

The combination of chemodynamic and photothermal materials can not only improve the therapeutic effect of chemodynamic therapy (CDT) by thermal stimulation, but also play a synergistic therapeutic role. Benefitting from the strong near-infrared absorption ability, copper sulfide (CuS) nanomaterials are widely used in photothermal therapy. However, due to the harsh preparation conditions, low photothermal efficiency and poor biocompatibility, further biomedical application is limited. In this work, silver-doped copper sulfide nanoparticles (BSA-Ag:CuS) were synthesized using a biomineralization strategy using bovine serum albumin (BSA) as a template and stabilizer. Silver doping greatly improved the near-infrared absorption and photothermal efficiency of CuS nanoparticles, which can be used for 1064 nm laser-guided photothermal therapy (PTT). Meanwhile, BSA-Ag:CuS nanoparticles had a synergistic therapeutic effect with CDT and thus showed excellent antitumor performance. In vivo and in vitro biological experiments have shown that BSA-Ag:CuS nanoparticles have good stability, low toxicity, good biocompatibility and strong antitumor ability, and are promising as antitumor agents for future clinical cancer treatment.

Near infrared photothermal conversion materials: mechanism, preparation, and photothermal cancer therapy applications

Photothermal therapy (PTT) has been widely applied in cancer therapy as a result of its non-invasive, localized treatment and good therapeutic effect. In general, the final therapeutic effect of PTT mainly depends on the photothermal materials, which can be further considered to be determined by the photothermal conversion efficiency, biocompatibility, and photothermal stability of photothermal materials. In this review, photothermal materials including inorganic materials, organic materials, and organic-inorganic composite materials in recent years have been summarized in terms of the mechanism, preparation, and cancer therapy applications. In the end, the perspectives and obstacles in their further development are overviewed.

Recent Advances in Gadolinium Based Contrast Agents for Bioimaging Applications

Gadolinium (Gd) based contrast agents (CAs) (Gd-CAs) represent one of the most advanced developments in the application of Gd for magnetic resonance imaging (MRI). Current challenges with existing CAs generated an urgent requirement to develop multimodal CAs with good biocompatibility, low toxicity, and prolonged circulation time. This review discussed the Gd-CAs used in bioimaging applications, addressing their advantages and limitations. Future research is required to establish the safety, efficacy and theragnostic capabilities of Gd-CAs. Nevertheless, these Gd-CAs offer extraordinary potential as imaging CAs and promise to benefit bioimaging applications significantly.

Recent Progress on NIR-II Photothermal Therapy

Photothermal therapy is a very promising treatment method in the field of cancer therapy. The photothermal nanomaterials in near-infrared region (NIR-I, 750-900 nm) attracts extensive attention in recent years because of the good biological penetration of NIR light. However, the penetration depth is still not enough for solid tumors due to high tissue scattering. The light in the second near-infrared region (NIR-II, 1000-1700 nm) allows deeper tissue penetration, higher upper limit of radiation and greater tissue tolerance than that in the NIR-I, and it shows greater application potential in photothermal conversion. This review summarizes the photothermal properties of Au nanomaterials, two-dimensional materials, metal oxide sulfides and polymers in the NIR-II and their application prospects in photothermal therapy. It will arouse the interest of scientists in the field of cancer treatment as well as nanomedicine.

Self-assembly of hyaluronic acid-mediated tumor-targeting theranostic nanoparticles

Theranostic nanoparticles (NPs) have emerged as promising candidates for cancer diagnosis and treatment. Manganese dioxide (MnO₂)-based NPs are potential contrast agents with excellent paramagnetic property and biocompatibility, exhibiting satisfactory magnetic resonance imaging (MRI) effects and biological safety. Recently, hyaluronic acid (HA) has gained increasing interest due to its tumor-targeting ability, which can improve the tumor affinity of manganese dioxide (MnO₂)-based NPs. In this study, HA-coated and albumin (BSA)-templated MnO₂ and polydopamine hybrid nanoparticles (HMDNs) with tumor-targeting and superior imaging capability were fabricated via modifying the nanoparticles prepared by integrating dopamine polymerization and MnO₂ biomineralization. The modification was found to enhance the cellular uptake of HMDNs by cancer cells. The prepared HMDN had high MRI contrasting capability with a longitudinal relaxivity of 22.2 mM^-1 s^-1 and strong photothermal therapy (PTT) effects with nearly complete tumor ablation under laser irradiation in vivo. HMDNs also showed effective clearance through kidneys, with no toxicity to important tissues. Therefore, HMDNs with superior imaging and PTT capability presented a new method to prepare tumor-targeting multifunctional nanotheranostics.

Current update on nanoplatforms as therapeutic and diagnostic tools: A review for the materials used as nanotheranostics and imaging modalities

In the last decade, the use of nanotheranostics as emerging diagnostic and therapeutic tools for various diseases, especially cancer, is held great attention. Up to date, several approaches have been employed in order to develop smart nanotheranostics, which combine bioactive targeting on specific tissues as well as diagnostic properties. The nanotheranostics can deliver therapeutic agents by concomitantly monitor the therapy response in real-time. Consequently, the possibility of over- or under-dosing is decreased. Various non-invasive imaging techniques have been used to quantitatively monitor the drug delivery processes. Radiolabeling of nanomaterials is widely used as powerful diagnostic approach on nuclear medicine imaging. In fact, various radiolabeled nanomaterials have been designed and developed for imaging tumors and other lesions due to their efficient characteristics. Inorganic nanoparticles as gold, silver, silica based nanomaterials or organic nanoparticles as polymers, carbon based nanomaterials, liposomes have been reported as multifunctional nanotheranostics. In this review, the imaging modalities according to their use in various diseases are summarized, providing special details for radiolabeling. In further, the most current nanotheranostics categorized via the used nanomaterials are also summed up. To conclude, this review can be beneficial for medical and pharmaceutical society as well as material scientists who work in the field of nanotheranostics since they can use this research as guide for producing newer and more efficient nanotheranostics.

Functional gadolinium-based nanoscale systems for cancer theranostics

Cancer theranostics is a new strategy for combating cancer that integrates cancer imaging and treatment through theranostic agents to provide an efficient and safe way to improve cancer prognosis. Design and synthesis of these cancer theranostic agents are crucial since these agents are required to be biocompatible, tumor-specific, imaging distinguishable and therapeutically efficacious. In this regard, several types of gadolinium (Gd)-based nanomaterials have been introduced to combine different therapeutic agents with Gd to enhance the efficacy of therapeutic agents. At the same time, the entire treatment procedure could be monitored via imaging tools due to incorporation of Gd ions, Gd chelates and Gd/other imaging probes in the theranostic agents. This review aims to overview recent advances in the Gd-based nanomaterials for cancer theranostics and perspectives for Gd nanomaterial-based cancer theranostics are provided.

Facile synthesis of polypyrrole-rhodamine B nanoparticles for self-monitored photothermal therapy of cancer cells

Photothermal therapy following microscopic temperature detection can avoid overheating effects or insufficient heating, and thus improve therapeutic efficacy. In this study, biocompatible dual-functional nanoparticles (NPs) are constructed from polypyrrole (PPy) and rhodamine B (RB) by a one-step modified polymerization method. The polypyrrole serves as a photothemal agent, and rhodamine B acts as a temperature-sensing probe. The polypyrrole-rhodamine B (PPy-RB) NPs possess a high photothermal effect on irradiation by 808 nm laser, and a competent temperature sensitivity for the real-time temperature monitoring based on the emission intensity response of rhodamine B. After acting on HepG2 cells, the PPy-RB NPs can effectively induce cancer cell death, and the microscopic temperature is monitored by fluorescence feedback from rhodamine B during PTT by laser confocal microscopy. Hence, the proposed approach can supply a facile and promising way for the fabrication of effective theranostic nanoplatforms assisted by self-monitoring of cancer therapeutic processes.

Protein-based nanoplatforms for tumor imaging and therapy

Cancer is one of the leading causes of death all over the world. The development of nanoplatform provides a promising strategy for the diagnosis and treatment of cancer. As the foundation of the nanoplatform, the composition of nanocarrier decides the basic properties. Protein exists in all kinds of life and participates in any life activities, having great potentials to serve as a nanocarrier because of its excellent biocompatibility, abundance of functional groups, and inherent biological activity. As a result, protein-based nanoplatforms have evoked extensive interests for tumor imaging and therapy. This review presents the latest progresses on the advancement of protein-based nanoplatforms, introducing the most common protein nanocarriers (such as human/bovine serum albumin, ferritin, human transferrin) thoroughly including their physiochemical properties and specific applications. Also, other kinds of protein are briefly involved. Finally, the prospects and challenges of the development of protein-based nanoplatforms are summarized. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

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.

Microfluidic Synthesis of Gd-Based Nanoparticles for Fast and Ultralong MRI Signals in the Solid Tumor

Clinically used magnetic resonance imaging contrast agents (MRI CAs) for solid tumors suffer from short life spans and low accumulation at the tumor for their low molecular weights. A good solution is to incorporate these MRI CAs into nanoparticles. Food and Drug Administration-approved compounds, poly(lactic-co-glycolic acid) (PLGA) and lipids, are chosen to assemble these nanoparticles. PLGA/lipid hybrid nanoparticles are assembled in microfluidic channels with a suitable size distribution for imaging tumors. These nanoparticles achieve clearly enhanced MRI contrast at the tumor at 0.5 h postinjection. The enhanced MRI contrast is sustained for 16 h. They can margin the tumor with as good an enhanced MRI contrast as clinical MRI CAs (which visualize the whole tumor) of the solid tumor with much less Gd. They are particularly useful for monitoring the solid tumor after therapy within a day and without repeated administration as clinical MRI CAs.

H2O2/near-infrared light-responsive nanotheronostics for MRI-guided synergistic chemo/photothermal cancer therapy

Aim: To develop a H₂O₂/near-infrared (NIR) laser light-responsive nanoplatform (manganese-doped Prussian blue@polypyrrole [MnPB@PPy]) for synergistic chemo/photothermal cancer theranostics. Materials & methods: Doxorubicin (DOX) was loaded onto the surface of polypyrrole shells. The in vitro and in vivo MRI performance and anticancer effects of these nanoparticles (NPs) were evaluated. Results: The MnPB@PPy NPs could not only generate heat under NIR laser irradiation for cancer photothermal therapy but also act as an excellent MRI contrast agent. The loaded DOX could be triggered to release by both NIR light and H₂O₂ to enhance synergistic therapeutic efficacy. The antitumor effects were confirmed by in vitro cellular cytotoxicity assays and in vivo treatment in a xenograft tumor model. Conclusion: The designed H₂O₂/NIR light-responsive MnPB@PPy-DOX NPs hold great potential for future biomedical applications.

Chitosan-mediated green synthesis and folic-acid modification of CuS quantum dots for photoacoustic imaging guided photothermal therapy of tumor

CuS nanomaterials capped with artificial organic-molecules or polymers have been well demonstrated as efficient photothermal nanoagents for the therapy of tumor, but their biocompatibility and target ability should be improved. To address these problems, we have used chitosan (CS) as the biomacromolecule model and surface ligands to prepare CuS quantum dots (QDs) via a simple co-precipitation method. CuS-CS QDs are then conjugated with folic acid (FA). The resulting CuS-CS-FA QDs are composed of hexagonal phase nanodots with sizes of about 4 nm. FA modification process has no apparent influence on the size, phase and composition of the QDs. Furthermore, the zeta potential and infrared spectroscopy confirm the efficient conjugation of FA. CuS-CS-FA QDs exhibit strong near-infrared photoabsorption and high photothermal efficiency (47.0%). As a result of the presence of CS ligand and FA modification, CuS-CS-FA QDs have good biocompatibility and relatively high cellular uptake efficacy. When CuS-CS-FA QD dispersion is injected intravenously into the tumor-bearing mice, the photoacoustic imaging reveals that CuS-CS-FA QD can be efficiently targeted and accumulated in the tumor and reach the peak dose at 60 min. The irradiation of 1064-nm laser (1.0 W cm^-2, 10 min) results in the efficient inhibition of tumor growth, without treatment-induced toxicity. Therefore, CuS-CS-FA QDs have great potential to become biocompatible multifunctional nanoagents for imaging guided therapy of tumor.

One-pot synthesis of polypyrrole nanoparticles with tunable photothermal conversion and drug loading capacity

With an excellent near-infrared (NIR) light-responsive property, polypyrrole (PPy) nanoparticle has emerged as a promising NIR photothermal transducing agent for tumor photothermal therapy (PTT). Herein, we reported the PVP mediated one-pot synthesis of colloidal stable and biocompatible PPy nanoparticles (PPy-PVP NPs) for combined tumor photothermal-chemotherapy. The influence of molecular weight and PVP concentration on the spectroscopic characteristic, photothermal feature, drug loading performance, and antitumor efficiency of the resultant PPy-PVP NPs was systematically studied. By choosing PVP with a molecular weight of 360 kDa (concentration of 5 mg/mL) as the template and surface modifier during the synthesis, PPy-PVP NPs with optimal spectroscopic characteristic, photothermal feature, drug loading performance, and antitumor efficiency were synthesized. Findings in this study are anticipated to provide an in-depth understanding of the important character of surface engineering in the rational design and biomedical applications of PPy NPs.

Enhancing magnetic resonance/photoluminescence imaging-guided photodynamic therapy by multiple pathways

Mitochondria, which are a major source of adenosine triphosphate (ATP) and apoptosis regulators, are the key organelles that promote tumor cell proliferation, and their dysfunction affects tumor cell behavior. Additionally, mitochondria have been shown to play a central role in the biosynthesis of protoporphyrin IX (PpIX), which is a widely used photosensitizer that has been used for tumor detection, monitoring and photodynamic therapy. Nevertheless, photosensitizers administrated exogenously are often restricted by limited bioavailability.δ-Aminolevulinic acid (δ-ALA) is a naturally occurring delta amino acid that can be converted in situ to PpIX via the heme biosynthetic pathway in mitochondria. Because δ-ALA is the precursor for PpIX, δ-ALA-based photodynamic therapy (PDT) shows promise in treating cancer. However, the accumulation of δ-ALA within endosomal system limits the production of PpIX and eventually impedes its effectiveness. Theranostic nanoparticles (NPs) capable of endosomal escape are expected to optimize the endogenous biosynthetic yield. In this study, δ-ALA was improved with triphenylphosphoniumcation (TPP⁺), a high net position cation that functions in endosomal escape and as a mitochondria-targeting ligand, and was further modified with bovine serum albumin stabilized manganese dioxide (MnO₂). The tumor microenvironment (TME) responsive MnO₂ in this system can elevate oxygen content to relieve hypoxia. Both enhanced photosensitizer yield and elevated oxygen contributing to the final therapeutic effect. Moreover, the enhancement of magnetic resonance imaging (MRI) (r₁ = 5.410 s^-1mM^-1) stemming from the degradation of MnO₂ by the TME could serve as a guide prior to treatment for accurate location, while in situ hysteretic photoluminescence imaging derived from PpIX can be utilize as a supervisor for prognosis evaluation. This systematic design could broaden the biomedical application and highlight the considerable therapeutic promise of PDT.

Integration of Polymerization and Biomineralization as a Strategy to Facilely Synthesize Nanotheranostic Agents

Integration of biological macromolecules with inorganic materials via biomineralization has demonstrated great potential for development of nanotheranostic agents. To produce multifunctionality, integration of multiple components in the biomineralized theranostic agents is required; however, how to efficiently and reproducibly implement this is challenging. In this report, a universal biomineralization strategy is developed by incorporation of oxidization polymerization into albumin-templated biomineralization for facile synthesis of nanotheranostic agents. A series of biomineralized polymers and manganese dioxide hybrid nanoparticles (PMHNs) can be synthesized via the polymerization of various monomers, including dopamine (DA), epigallocatechin (EGC), pyrrole (PY), and diaminopyridine (DP), along with the reduction of KMnO₄ and formation of manganese dioxide nanoparticles in albumin templates. These biomineralized PMHNs demonstrate ultrahigh MRI (longitudinal relaxivity up to 38 mM^-1 s^-1) and ultrasonic (US) imaging contrasting capabilities and have excellent photothermal therapy efficacy with complete ablation of orthotopic tumors. Moreover, these biomineralized hybrid nanoparticles can be effectively excreted through the kidneys, avoiding potential systemic toxicity. Thus, integration of polymerization into biomineralization presents a strategy for the fabrication of hybrid nanomaterials, allowing the production of multifunctional and biocompatible nanotheranostic agents via a facile one-pot method.

Ultrasmall All-In-One Nanodots Formed via Carbon Dot-Mediated and Albumin-Based Synthesis: Multimodal Imaging-Guided and Mild Laser-Enhanced Cancer Therapy

Integration of multiple diagnostic/therapeutic modalities into a single system with ultrasmall size, excellent photothermal/photodynamic properties, high cellular uptake efficiency, nuclear delivery capacity, rapid renal clearance, and good biosafety is highly desirable for cancer theranostics, but still remains challenging. Here, a novel type of multifunctional nanodots (denoted as BCCGH) was synthesized by mixing bovine serum albumin, carbon dots, and metal ions (Cu²⁺ and Gd³⁺), followed by the conjugation with a photosensitizer (HPPH). The nanodots hold great promise for fluorescence/photoacoustic/magnetic resonance/photothermal imaging-guided synergistic photothermal/photodynamic therapy (PDT) because of their appealing properties such as high photothermal conversion efficiency (68.4%), high longitudinal relaxivity (11.84 mM^-1 s^-1, 7 T), and superior colloidal stability with negligible Gd³⁺ release. Benefiting from the massive cellular uptake, endoplasmic reticulum/mitochondrion-targeting ability, and mild near-infrared laser irradiation-promoted nuclear delivery of BCCGH, a high anticancer therapeutic efficiency is achieved in the subsequent in vitro PDT. Besides, as revealed by the in vivo/ex vivo results, the nanodots also exhibit excellent tumor accumulation, efficient renal clearance, complete tumor ablation, and exceptional biosafety. To summarize, this work develops a carbon dot-mediated and albumin-based synthetic approach for constructing ultrasmall and multifunctional nanodots, which may hold great potential for cancer theranostics and beyond.

Sub-10 nm Cu5FeS4 cube for magnetic resonance imaging-guided photothermal therapy of cancer

BACKGROUND

Facile synthesis and small size theranostic agents have shown great potential for cancer diagnosis and treatment.

PURPOSE

A ternary compound (Cu5FeS4), Fe doped copper sulfide, with novel magnetic properties and strong near-infrared absorption was prepared for magnetic resonance imaging (MRI) imaging guided photothermal therapy of cancer.

PATIENTS AND METHODS

Firstly, the capability of magnetic resonance imaging based on the novel magnetic properties and the photothermal performance due to the strong near-infrared absorption was investigated in vitro. Then, the magnetic resonance imaging guided photothermal therapy for 4T1 tumor-bearing mouse was carried out.

RESULTS

The Cu5FeS4 cube with good T1-weighted MRI, excellent photothermal performance and low cytotoxicity has been investigated. More importantly, the T1-weighted MRI for 4T1 tumor-bearing mouse will get the best contrast effect at tumor site after 8 h of intravenous injection of Cu5FeS4 cube. Under the guidance of the T1-weighted MRI, the PTT was carried out at 8 h after intravenous injection of Cu5FeS4 cube and only the group combined intravenous administration of Cu5FeS4 cube and laser irradiation nearly cured the tumor after 14 days.

CONCLUSION

Our study not only provides a new material for personalized treatment of tumors, but also further promotes potential applications of the cancer theranostic agents.

One-Step Synthesis of Iodinated Polypyrrole Nanoparticles for CT Imaging Guided Photothermal Therapy of Tumors

Theranostic materials are of great significance to a personalized precise medicine. However, conventional theranostic agents are mainly fabricated by combining presynthesized independent imaging probes and therapeutic agents, suffering from multiple synthesis procedures, poor morphological control, and time/reagent-consuming process. Herein, iodinated polypyrrole (I-PPy) nanoparticles are fabricated via a one-step synthesis strategy combining chemical oxidation and iodination for computed tomography (CT) imaging-guided photothermal therapy. Iodic acid with a high standard electrode potential enables the chemical oxidation polymerization of pyrrole monomers. Meanwhile, the iodination of PPy induced by the corresponding reduction product I₂ takes place during the polymerization process to generate I-PPy nanoparticles. The prepared I-PPy nanoparticles possess a uniform size, excellent colloidal stability, intense near-infrared absorption, strong X-ray attenuation ability, and favorable biocompatibility. The as-synthesized I-PPy nanoparticles not only guarantee remarkable contrast-enhanced CT imaging of blood pool and tumors, but also realize effective tumor suppression in vitro and in vivo by I-PPy nanoparticles-mediated CT imaging-guided photothermal therapy. To the best of the authors' knowledge, it is the first time that multifunctional PPy nanoparticles are fabricated through a one-step synthesis process. The proposed strategy opens up a new way for the fabrication of high-performance theranostic agents via a one-step strategy under mild conditions.

Multifunctional Supramolecular Materials Constructed from Polypyrrole@UiO-66 Nanohybrids and Pillararene Nanovalves for Targeted Chemophotothermal Therapy

Multifunctional supramolecular nanomaterials capable of targeted and multimodal therapy hold great potential to improve the efficiency of cancer therapeutics. Herein, we report a proof-of-concept nanoplatform for effective chemophotothermal therapy via the integration of folic acid-based active targeting and supramolecular nanovalves-based passive targeting. Inspired by facile surface engineering and designable layer-by-layer assembly concept, we design and synthesize PPy@UiO-66@WP6@PEI-Fa nanoparticles (PUWPFa NPs) to achieve efficient synergistic chemophotothermal therapy, taking advantage of the desirable photothermal conversion capability of polypyrrole nanoparticles (PPy NPs) and high drug-loading capacity of hybrid scaffolds. Significantly, pillararene-based pseudorotaxanes as pH/temperature dual-responsive nanovalves allow targeted drug delivery in pathological environment with sustained release over 4 days, which is complementary to photothermal therapy, and folic acid-conjugated polyethyleneimine (PEI-Fa) at the outmost layer through electrostatic interactions is able to enhance tumor-targeting and therapeutic efficiency. Such PUWPFa NPs showed efficient synergistic chemophotothermal therapy of cervical cancer both in vitro and in vivo. The present strategy offers not only the distinctly targeted drug delivery and release, but also excellent tumor inhibition efficacy of simultaneous chemophotothermal therapy, opening a new avenue for effective cancer treatment.

Sacrificial template-based synthetic approach of polypyrrole hollow fibers for photothermal therapy

In the present work, polypyrrole hollow fibers (PPy-HFs) were fabricated by sacrificial removal of soft templates of electrospun polycaprolactone (PCL) fibers with polypyrrole (PPy) coating through chemical polymerization of pyrrole monomer. Different physicochemical properties of as-fabricated PPy-HFs were then studied by Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infra-red (FT-IR) spectroscopy, Differential scanning calorimetry/Thermogravimetric analysis (DSC/TGA), and X-ray photoelectron spectroscopy (XPS). The photothermal activity of PPy-HF was studied by irradiating 808-nm near infra-red (NIR) light under different power values with various concentrations of PPy-HFs dispersed in phosphate buffer solution (PBS, pH 7.4). These PPy-HFs exhibited enhanced photothermal performance compared with polypyrrole nanoparticles (PPy-NPs). Furthermore, these PPy-HFs showed photothermal effect that was laser-power- and concentration-dependent. The photothermal toxicity of the resulting nanofiber was evaluated using cell counting kit-8 (CCK-8) and live and dead cell assays. Results showed that these PPy-HFs were more effective in killing cancer cells under NIR irradiation. In contrast, hollow-fiber showed no cytotoxicity without NIR exposure. Among different nanofiber formulations, PPy-160 exhibited the highest photothermal toxicity. It could be explained by its enhanced photothermal performance compared to other specimens. The resulting PPy-HFs showed superior drug-loading capacity to PPy-NPs. This might be attributed to adequate binding of the drug into both luminal and abluminal hollow-fiber surfaces. Fabrication of this substrate type opens a promising new avenue for architectural design of biocompatible organic polymer for biomedical field.

Sorafenib and indocyanine green co-loaded in photothermally sensitive liposomes for diagnosis and treatment of advanced hepatocellular carcinoma

Sorafenib (SF), as an irreplaceable first-line drug to help advanced hepatocellular carcinoma (HCC) patients to prolong their lives, has already been used in clinical practice for several years. However, this treatment causes several side effects, and few alternatives to SF treatment exist. Herein, we designed NIR fluorescence imaging-guided photothermally sensitive nanoliposomes based on co-encapsulation of SF and the clinical photothermal and photodynamic therapy agent Indocyanine Green (ICG) to solve the problems of SF-based treatment in advanced HCC. As expected, in vitro and in vivo drug release studies on SF-ICG liposomes (SILs) demonstrated SF release from SILs compared with free SF at the same concentration. In addition, in vivo NIR fluorescence imaging and anti-tumor treatment using SILs have been demonstrated by using Hep3B tumor-bearing xenograft nude mice. All detailed experimental evidence suggested that biocompatibility, biotoxicity, and anti-tumor effects were improved by using SILs instead of free SF. In conclusion, our designed SILs could present a novel and suitable SF-based treatment strategy for advanced HCC therapy in the future.

Fe3O4@MnO2@PPy nanocomposites overcome hypoxia: magnetic-targeting-assisted controlled chemotherapy and enhanced photodynamic/photothermal therapy

Here, a multifunctional nanocomposite composed by a core of iron oxide (Fe₃O₄) and two shells of manganese dioxide (MnO₂) and polypyrrole (PPy) was successfully designed and synthesized for drug delivery and magnetic targeting assisted synergistic effects of chemotherapy and improved PDT/PTT.

Semiconducting polymer-based nanoparticles for photothermal therapy at the second near-infrared window

We designed novel diketopyrrolopyrrole polymer based nanoparticles (DPP-IID-FA), which exhibited strong light absorption and excellent photothermal conversion in the NIR optical window, and displayed high biocompatibility and photostability.