Silica-coated bismuth sulfide nanorods as multimodal contrast agents for a non-invasive visualization of the gastrointestinal tract

Evaluating the adverse effects and mechanisms of nanomaterial exposure on longevity of C. elegans: A literature meta-analysis and bioinformatics analysis of multi-transcriptome data

Exposure to large-size particulate air pollution (PM2.5 or PM10) has been reported to increase risks of aging-related diseases and human death, indicating the potential pro-aging effects of airborne nanomaterials with ultra-fine particle size (which have been widely applied in various fields). However, this hypothesis remains inconclusive. Here, a meta-analysis of 99 published literatures collected from electronic databases (PubMed, EMBASE and Cochrane Library; from inception to June 2023) was performed to confirm the effects of nanomaterial exposure on aging-related indicators and molecular mechanisms in model animal C. elegans. The pooled analysis by Stata software showed that compared with the control, nanomaterial exposure significantly shortened the mean lifespan [standardized mean difference (SMD) = -2.30], reduced the survival rate (SMD = -4.57) and increased the death risk (hazard ratio = 1.36) accompanied by upregulation of ced-3, ced-4 and cep-1, while downregulation of ctl-2, ape-1, aak-2 and pmk-1. Furthermore, multi-transcriptome data associated with nanomaterial exposure were retrieved from Gene Expression Omnibus (GSE32521, GSE41486, GSE24847, GSE59470, GSE70509, GSE14932, GSE93187, GSE114881, and GSE122728) and bioinformatics analyses showed that pseudogene prg-2, mRNAs of abu, car-1, gipc-1, gsp-3, kat-1, pod-2, acdh-8, hsp-60 and egrh-2 were downregulated, while R04A9.7 was upregulated after exposure to at least two types of nanomaterials. Resveratrol (abu, hsp-60, pod-2, egrh-2, acdh-8, gsp-3, car-1, kat-1, gipc-1), naringenin (kat-1, egrh-2), coumestrol (egrh-2) or swainsonine/niacin/ferulic acid (R04A9.7) exerted therapeutic effects by reversing the expression levels of target genes. In conclusion, our study demonstrates the necessity to use phytomedicines that target hub genes to delay aging for populations with nanomaterial exposure.

Achieving safe and high-performance gastrointestinal tract spectral CT imaging with small-molecule lanthanide complex

BACKGROUND

Non-intrusive imaging of gastrointestinal (GI) tract using computed tomography (CT) contrast agents is of the most significant issues in the diagnosis and treatment of GI diseases. Moreover, spectral CT, which can generate monochromatic images to display the X-ray attenuation characteristics of contrast agents, provides a better imaging sensitivity for diagnose inflammatory bowel disease (IBD) than convention CT imaging.

METHODS

Herein, a convenient and one-pot synthesis method is provided for the fabrication of small-molecule lanthanide complex Holmium-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (Ho-DOTA) as a biosafe and high-performance spectral CT contrast agent for GI imaging with IBD. In vivo CT imaging was administered with both healthy mice and colitis mice induced by dextran sodium sulfate.

RESULTS

We found that Ho-DOTA accumulated in inflammation sites of large intestines and produced high CT contrast compared with healthy mice. Both in vitro and in vivo experimental results also showed that Ho-DOTA provided much more diagnostic sensitivity and accuracy due to the excellent X-ray attenuation characteristics of Ho-DOTA compared with clinical iodinate agent. Furthermore, the proposed contrast media could be timely excreted from the body via the urinary and digestive system, keeping away from the potential side effects due to long-term retention in vivo.

CONCLUSION

Accordingly, Ho-DOTA with excellent biocompatibility can be useful as a potential high-performance spectral CT contrast agent for further clinical imaging of gastrointestinal tract and diagnosis of intestinal system diseases.

Noninvasive Gastrointestinal Tract Imaging Using BSA-Ag2Te Quantum Dots as a CT/NIR-II Fluorescence Dual-Modal Imaging Probe in Vivo

The combination of high-resolution computed tomography (CT) and the real-time sensitive second near-infrared window (NIR-II) fluorescence bioimaging can provide complementary information for the diagnosis, progression and prognosis of gastrointestinal disorders. Ag₂Te quantum dots (QDs) are a kind of promising CT/NIR-II fluorescence dual-modal imaging probe due to their high atomic number and narrow bandgap. However, conventional Ag₂Te QDs synthesized by oil phase approaches often suffer from complicated steps, harsh reaction conditions, and toxic organic solvents. Herein, we report the synthesis of bovine serum albumin (BSA)-Ag₂Te QDs using a biomineralization approach for CT/NIR-II fluorescence dual-modal imaging of the gastrointestinal tract. The BSA-Ag₂Te QDs are fabricated in a facile one-pot approach under mild conditions and exhibit homogeneous size, favorable monodispersity, admirable aqueous solubility, excellent X-ray attenuation properties, and outstanding NIR-II fluorescence performance. In vivo imaging experiments show that BSA-Ag₂Te QDs can be used in gastrointestinal tract CT/NIR-II dual-modal imaging with high spatiotemporal resolution and sensitivity. In addition, in an intestinal obstruction mouse model, accurate lesion positioning and imaging-guided obstruction relief surgery are successfully realized based on BSA-Ag₂Te QDs. Besides, BSA-Ag₂Te QDs have outstanding biocompatibility in vitro and in vivo. This study presents a high-performance and biosafe CT/NIR-II fluorescence dual-modal imaging probe for visualizing the gastrointestinal tract in vivo.

Fabrication of gelatin Bi2S3 capsules as a highly sensitive X-ray contrast agent for gastrointestinal motility assessment in vivo

Tiny BaSO₄ rod-based X-ray imaging is the most frequently-used method for clinical diagnosis of gastrointestinal motility disorders. The BaSO₄ rods usually have a small size to pass through the gastrointestinal tract smoothly, but suffer from unavoidably low sensitivity. Herein, we developed Bi₂S₃ capsules as a high-performance X-ray contrast agent for gastrointestinal motility assessment for the first time. The Bi₂S₃ capsules were synthesized by the encapsulation of commercial Bi₂S₃ powder into commercial gelatin capsules and subsequent coating of ultraviolet-curable resin. The prepared Bi₂S₃ capsules showed excellent biocompatibility in vitro and in vivo and superior X-ray attenuation ability due to the large atomic number and high K-edge value of Bi. The developed Bi₂S₃ capsules can serve as a small but highly sensitive X-ray contrast agent to quantitatively assess gastrointestinal motility in a vincristine-induced gastrointestinal motility disorder model in vivo by X-ray, CT and spectral CT imaging successfully, solving the intrinsic drawbacks of clinically used BaSO₄.

Orally administered Bi2S3@SiO2 core-shell nanomaterials as gastrointestinal contrast agents and their influence on gut microbiota

Effective and safe contrast agents for X-ray computed tomography (CT) imaging of the gastrointestinal (GI) tract are quite desirable for realizing high diagnostic accuracy and low toxicity in the clinic. Herein, we synthesize a series of silica-coated bismuth sulfide core-shell nanomaterials (Bi2S3@SiO2) of various sizes and systematically study their GI CT contrast performance and potential toxic effects in comparison with those of barium sulfate (BaSO4) in mice. The in vivo experimental results suggest that these Bi2S3@SiO2 core-shell nanomaterials display superior CT contrast performance and higher elimination efficacy than BaSO4 by single-dose exposure manner (10 ​mg/kg Bi element/b.w. for Bi2S3@SiO2 versus 30 ​mg/kg Ba element/b.w. for BaSO4). Furthermore, 28 days after exposure, Bi2S3@SiO2 core-shell nanomaterials show minimal toxic effects in vivo and nonsignificant influences on the structure and function of the gut microbiota in mice. This demonstrates that no adverse effects on the gut homeostasis are induced by Bi2S3@SiO2 core-shell nanomaterials and, thus, suggests that they can act as excellent and safe CT contrast agents for GI tract imaging.

Gram-scale synthesis of a neodymium chelate as a spectral CT and second near-infrared window imaging agent for visualizing the gastrointestinal tract in vivo

The diagnosis of gastrointestinal (GI) tract diseases is frequently performed in the clinic, so it is crucial to develop high-performance contrast agents for real-time and non-invasive imaging examination of the GI tract. Herein, we show a novel method to synthesize a neodymium (Nd) chelate, Nd-diethylenetriaminepentaacetic acid (Nd-DTPA), on a large scale without byproducts for spectral computed tomography (CT) and second near-infrared window imaging of the GI tract in vivo. The Nd-DTPA was simply generated by heating the mixture of Nd2O3 and DTPA in water at 85 °C for 2 h. This dual-modal imaging agent has the advantages of a simple and green synthesis route, no need of purification process, high yield (86.24%), large-scale production capability (>10 g in lab synthesis), good chemical stability and excellent water solubility (≈2 g mL-1). Moreover, the Nd-DTPA emitted strong near-infrared fluorescence at 1308 nm, and exhibited superior X-ray attenuation ability compared to clinical iohexol. The proposed Nd-DTPA can integrate the complementary merits of dual-modal imaging to realize spatial-temporal and highly sensitive imaging of the GI tract in vivo, and accurate diagnosis of the location of intestinal obstruction and monitor its recovery after surgery. The developed highly efficient method for the gram-scale synthesis of Nd-DTPA and the proposed spectral CT and second near-infrared window dual-modal imaging strategy provide a promising route for accurate visualization of the GI tract in vivo.

Engineering of bioactive metal sulfide nanomaterials for cancer therapy

Metal sulfide nanomaterials (MeSNs) are a novel class of metal-containing nanomaterials composed of metal ions and sulfur compounds. During the past decade, scientists found that the MeSNs engineered by specific approaches not only had high biocompatibility but also exhibited unique physicochemical properties for cancer therapy, such as Fenton catalysis, light conversion, radiation enhancement, and immune activation. To clarify the development and promote the clinical transformation of MeSNs, the first section of this paper describes the appropriate fabrication approaches of MeSNs for medical science and analyzes the features and limitations of each approach. Secondly, we sort out the mechanisms of functional MeSNs in cancer therapy, including drug delivery, phototherapy, radiotherapy, chemodynamic therapy, gas therapy, and immunotherapy. It is worth noting that the intact MeSNs and the degradation products of MeSNs can exert different types of anti-tumor activities. Thus, MeSNs usually exhibit synergistic antitumor properties. Finally, future expectations and challenges of MeSNs in the research of translational medicine are spotlighted.

Pnictogen Semimetal (Sb, Bi)-Based Nanomaterials for Cancer Imaging and Therapy: A Materials Perspective

Innovative multifunctional nanomaterials have attracted tremendous interest in current research by facilitating simultaneous cancer imaging and therapy. Among them, antimony (Sb)- and bismuth (Bi)-based nanoparticles are important species with multifunction to boost cancer theranostic efficacy. Despite the rapid development, the extensive previous work treated Sb- and Bi-based nanoparticles as mutually independent species, and therefore a thorough understanding of their relationship in cancer theranostics was lacking. We propose here that the identical chemical nature of Sb and Bi, being semimetals, provides their derived nanoparticles with inherent multifunction for near-infrared laser-driven and/or X-ray-based cancer imaging and therapy as well as some other imparted functions. An overview of recent progress on Sb- and Bi-based nanoparticles for cancer theranostics is provided to highlight the relationship between chemical nature and multifunction. The understanding of Sb- and Bi-based nanoparticles in this way might shed light on the further design of smart multifunctional nanoparticles for cancer theranostics.

Bistratal Au@Bi2S3 nanobones for excellent NIR-triggered/multimodal imaging-guided synergistic therapy for liver cancer

To fabricate a highly biocompatible nanoplatform enabling synergistic therapy and real-time imaging, novel Au@Bi2S3 core shell nanobones (NBs) (Au@Bi2S3 NBs) with Au nanorods as cores were synthesized. The combination of Au nanorods with Bi2S3 film made the Au@Bi2S3 NBs exhibit ultrahigh photothermal (PT) conversion efficiency, remarkable photoacoustic (PA) imaging and high computed tomography (CT) performance; these Au@Bi2S3 NBs thus are a promising nanotheranostic agent for PT/PA/CT imaging. Subsequently, poly(N-vinylpyrrolidone)-modified Au@Bi2S3 NBs (Au@Bi2S3-PVP NBs) were successfully loaded with the anticancer drug doxorubicin (DOX), and a satisfactory pH sensitive release profile was achieved, thus revealing the great potential of Au@Bi2S3-PVP NBs in chemotherapy as a drug carrier to deliver DOX into cancer cells. Both in vitro and in vivo investigations demonstrated that the Au@Bi2S3-PVP NBs possessed multiple desired features for cancer therapy, including extremely low toxicity, good biocompatibility, high drug loading ability, precise tumor targeting and effective accumulation. Highly efficient ablation of the human liver cancer cell HepG2 was achieved through Au@Bi2S3-PVP NB-mediated photothermal therapy (PTT). As both a contrast enhancement probe and therapeutic agent, Au@Bi2S3-PVP NBs provided outstanding NIR-triggered multi-modal PT/PA/CT imaging-guided PTT and effectively inhibited the growth of HepG2 liver cancer cells via synergistic chemo/PT therapy.

A Review on the Biodistribution, Pharmacokinetics and Toxicity of Bismuth-Based Nanomaterials

Here, bismuth-based nanomaterials (Bi-based NMs) are introduced as promising theranostic agents to enhance image contrast as well as for the therapeutic gain for numerous diseases. However, understanding the interaction of such novel developed nanoparticles (NPs) within a biological environment is a requisite for the translation of any promising agent from the lab bench to the clinic. This interaction delineates the fate of NPs after circulation in the body. In an ideal setting, a nano-based therapeutic agent should be eliminated via the renal clearance pathway, meanwhile it should have specific targeting to a diseased organ to reach an effective dose and also to overcome off-targeting. Due to their clearance pathway, biodistribution patterns and pharmacokinetics (PK), Bi-based NMs have been found to play a determinative role to pass clinical approval and they have been investigated extensively in vivo to date. In this review, we expansively discuss the possible toxicity induced by Bi-based NMs on cells or organs, as well as biodistribution profiles, PK and the clearance pathways in animal models. A low cytotoxicity of Bi-based NMs has been found in vitro and in vivo, and along with their long-term biodistribution and proper renal clearance in animal models, the translation of Bi-based NMs to the clinic as a useful novel theranostic agent is promising to improve numerous medical applications.

The Novel DPP-BDT Nanoparticles as Efficient Photoacoustic Imaging and Positron Emission Tomography Agents in Living Mice

Background

Molecular imaging is of great benefit to early disease diagnosis and timely treatment. One of the most striking innovations is the development of multimodal molecular imaging technology, which integrates two or more imaging modalities, largely in view of making the best of the advantages of each modality while overcoming their respective shortcomings. Hence, engineering a versatile and easily prepared nanomaterial with integrating multimodal molecular imaging function holds great promise, but is still a great challenge.

Materials and Methods

We firstly designed and synthesized a BDT-DPP conjugated polymer and then noncovalent self-assembly with phospholipid-polyethylene glycol endowed BDT-DPP with water solubility and biocompatibility. Followed by [Cu] labeling, the acquired multifunctional nanoparticles (NPs) were studied in detail for the photophysical property. The cytotoxicity and biocompatibility of DPP-BDT NPs were examined through MTT assay and H&E stained analysis. In addition, we investigated the accumulation of the NPs in HepG2 tumor models by positron emission tomography (PET) and photoacoustic (PA) dual-mode imaging.

Results and Discussion

The DPP-BDT NPs exhibited excellent optical stability, strong near-infrared (NIR) light absorption as well as fine biocompatibility. After tail vein injection into the living mice, the PA signals in the neoplastic tissues were gradually increased and reached to the maximum at the 4-h post-injection, which was consistent with the PET analysis. Such strong PA and PET signals were attributed to the efficient NPs accumulation resulting from the enhanced permeability and retention (EPR) effect.

Conclusion

The biocompatible DPP-BDT NPs demonstrated to be strong NIR absorption property and PAI sensitivity. Besides, these novel DPP-BDT NPs can act not only as a PA imaging contrast agent but also as an imaging agent for PET.

Polydopamine-coated downconversion nanoparticle as an efficient dual-modal near-infrared-II fluorescence and photoacoustic contrast agent for non-invasive visualization of gastrointestinal tract in vivo

Herein, a multifunctional dual-modal imaging probe is successfully developed to integrate the advantages of second near-infrared window (NIR-II, 1000-1700 nm) fluorescence imaging (FI) and photoacoustic imaging (PAI) with the ultimate goal of improving diseases diagnosis and management. Melanin-inspired polydopamine (PDA) polymer coated NaYF4:Yb3+,Er3+@NaYbF4@NaYF4:Nd3+ down conversion nanoparticles (DCNPs) is designed via water-in-oil microemulsion method, which comprises a DCNP core, acting as the NIR-II optical imaging agent, and a PDA shell, acting as the PA contrast agent. By taking the advantages of high spatial resolution and excellent temporal resolution, the dual-modal contrast agent is capable for high sensitivity real-time visualization of gastrointestinal tract, diagnosis of gastrointestinal peristalsis disorder and NIR-II FI-guided intestinal obstruction surgery. All of the above results demonstrate the great potential of DCNP@PDA NP as an efficient NIR-II/PAI dual-modal contrast agent for precision medicine.

The versatile biomedical applications of bismuth-based nanoparticles and composites: therapeutic, diagnostic, biosensing, and regenerative properties

Studies of nanosized forms of bismuth (Bi)-containing materials have recently expanded from optical, chemical, electronic, and engineering fields towards biomedicine, as a result of their safety, cost-effective fabrication processes, large surface area, high stability, and high versatility in terms of shape, size, and porosity. Bi, as a nontoxic and inexpensive diamagnetic heavy metal, has been used for the fabrication of various nanoparticles (NPs) with unique structural, physicochemical, and compositional features to combine various properties, such as a favourably high X-ray attenuation coefficient and near-infrared (NIR) absorbance, excellent light-to-heat conversion efficiency, and a long circulation half-life. These features have rendered bismuth-containing nanoparticles (BiNPs) with desirable performance for combined cancer therapy, photothermal and radiation therapy (RT), multimodal imaging, theranostics, drug delivery, biosensing, and tissue engineering. Bismuth oxyhalides (BiO_x, where X is Cl, Br or I) and bismuth chalcogenides, including bismuth oxide, bismuth sulfide, bismuth selenide, and bismuth telluride, have been heavily investigated for therapeutic purposes. The pharmacokinetics of these BiNPs can be easily improved via the facile modification of their surfaces with biocompatible polymers and proteins, resulting in enhanced colloidal stability, extended blood circulation, and reduced toxicity. Desirable antibacterial effects, bone regeneration potential, and tumor growth suppression under NIR laser radiation are the main biomedical research areas involving BiNPs that have opened up a new paradigm for their future clinical translation. This review emphasizes the synthesis and state-of-the-art progress related to the biomedical applications of BiNPs with different structures, sizes, and compositions. Furthermore, a comprehensive discussion focusing on challenges and future opportunities is presented.

Rod-shape theranostic nanoparticles facilitate antiretroviral drug biodistribution and activity in human immunodeficiency virus susceptible cells and tissues

Human immunodeficiency virus theranostics facilitates the development of long acting (LA) antiretroviral drugs (ARVs) by defining drug-particle cell depots. Optimal drug formulations are made possible based on precise particle composition, structure, shape and size. Through the creation of rod-shaped particles of defined sizes reflective of native LA drugs, theranostic probes can be deployed to measure particle-cell and tissue biodistribution, antiretroviral activities and drug retention.

Methods: Herein, we created multimodal rilpivirine (RPV) ¹⁷⁷lutetium labeled bismuth sulfide nanorods (¹⁷⁷LuBSNRs) then evaluated their structure, morphology, configuration, chemical composition, biological responses and adverse reactions. Particle biodistribution was analyzed by single photon emission computed tomography (SPECT/CT) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging.

Results: Nanoformulated RPV and BSNRs-RPV particles showed comparable physicochemical and cell biological properties. Drug-particle pharmacokinetics (PK) and biodistribution in lymphoid tissue macrophages proved equivalent, one with the other. Rapid particle uptake and tissue distribution were observed, without adverse reactions, in primary blood-derived and tissue macrophages. The latter was seen within the marginal zones of spleen.

Conclusions: These data, taken together, support the use of ¹⁷⁷LuBSNRs as theranostic probes as a rapid assessment tool for PK LA ARV measurements.

A Safe-by-Design Strategy towards Safer Nanomaterials in Nanomedicines

The marriage of nanotechnology and medicine offers new opportunities to fight against human diseases. Benefiting from their unique optical, thermal, magnetic, or redox properties, a wide range of nanomaterials have shown potential in applications such as diagnosis, drug delivery, or tissue repair and regeneration. Despite the considerable success achieved over the past decades, the newly emerging nanomedicines still suffer from an incomplete understanding of their safety risks, and of the relationships between their physicochemical characteristics and safety profiles. Herein, the most important categories of nanomaterials with clinical potential and their toxicological mechanisms are summarized, and then, based on this available information, an overview of the principles in developing safe-by-design nanomaterials for medical applications and of the recent progress in this field is provided. These principles may serve as a starting point to guide the development of more effective safe-by-design strategies and to help identify the major knowledge and skill gaps.

Rhenium Sulfide Nanoparticles as a Biosafe Spectral CT Contrast Agent for Gastrointestinal Tract Imaging and Tumor Theranostics in Vivo

Spectral computed tomography (CT) imaging as a novel imaging technique shows promising prospects in the accurate diagnosis of various diseases. However, clinically iodinated contrast agents suffer from poor signal-to-noise ratio, and emerging heavy-metal-based CT contrast agents arouse great biosafety concern. Herein, we show the fabrication of rhenium sulfide (ReS₂) nanoparticles, a clinic radiotherapy sensitizer, as a biosafe spectral CT contrast agent for the gastrointestinal tract imaging and tumor theranostics in vivo by teaching old drugs new tricks. The ReS₂ nanoparticles were fabricated in a one-pot facile method at room temperature, and exhibited sub-10 nm size, favorable monodispersity, admirable aqueous solubility, and strong X-ray attenuation capability. More importantly, the proposed nanoparticles possess an outstanding spectral CT imaging ability and undoubted biosafety as a clinic therapeutic agent. Besides, the ReS₂ nanoparticles possess appealing photothermal performance due to their intense near-infrared absorption. The proposed nano-agent not only guarantees obvious contrast enhancement in gastrointestinal tract spectral CT imaging in vivo, but also allows effective CT imaging-guided tumor photothermal therapy. The proposed "teaching old drugs new tricks" strategy shortens the time and cuts the cost required for clinical application of nano-agents based on existing clinical toxicology testing and trial results, and lays down a low-cost, time-saving, and energy-saving method for the development of multifunctional nano-agents toward clinical applications.

In Vivo Quantitative Photoacoustic Diagnosis of Gastric and Intestinal Dysfunctions with a Broad pH-Responsive Sensor

Gastrointestinal diseases affect many people in the world and significantly impair life quality and burden the healthcare system. The functional parameters of the gastrointestinal tract such as motility and pH can effectively reflect the changes of gastrointestinal activity in physiological and pathological conditions. Thus, a noninvasive method for real-time and quantitative measurement of gastrointestinal functional parameters in vivo is highly desired. At present, there are many strategies widely used for the diagnosis of gastrointestinal diseases in clinic, including X-ray barium meal examination, ultrasound imaging, radionuclide examination, endoscopy, etc. However, these methods are limited in determining the gastrointestinal status and cannot provide comprehensive quantitative information. Photoacoustic imaging (PAI) is a rapid noninvasive real-time imaging technique in which multiple types of functional and quantitative information can be simultaneously obtained. Unfortunately, very few ratiometric PAI contrast agents have been reported for quantification of gastrointestinal functional parameters in vivo. In this work, a broad, pH-responsive ratiometric sensor based on polyaniline and Au triangular nanoplates was developed. Utilizing the sensor as a contrast agent, PAI served as an all-in-one technique, accurately measuring the gastrointestinal functional parameters in a single test. Notably, this sensor was examined to be ultrasensitive with pH responses as fast as 0.6 s and durability as long as 24 h, and was repeatable and reversible for longitudinal monitoring. The quantitative results demonstrated a significant disorder in motility and decrease in pH for gastric and duodenal ulcers. Collectively, the combination of PAI and this broad pH-responsive sensor might be a promising candidate for quantitative diagnosis of gastrointestinal diseases.

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.

Flower-like Fe7S8/Bi2S3 superstructures with improved near-infrared absorption for efficient chemo-photothermal therapy

Although various photothermal therapy (PTT) nanoagents have been developed in recent years, the rational design and easy synthesis of a PTT nanoplatform with improved near-infrared (NIR) absorption have remained challenging. Herein, via a facile one-pot solvothermal strategy, hydrophilic nanosheet-assembled flower-like Fe7S8/Bi2S3 superstructures were fabricated successfully. Such nanoflowers exhibit improved NIR absorption, which is 1.54 times higher than that of pure Bi2S3 nanosheets at a wavelength of 808 nm. Attractively, these nanoflowers could serve as a drug delivery carrier with controlled release under pH/NIR stimuli and display a fascinating chemo-photothermal synergetic therapeutic effect both in vitro and vivo. The resulting nanoflowers may open up a way for the design of other nanoagents with an improved NIR absorption and chemo-photothermal cancer therapy effect.

Biocompatible Heat-Shock Protein Inhibitor-Delivered Flowerlike Short-Wave Infrared Nanoprobe for Mild Temperature-Driven Highly Efficient Tumor Ablation

Multifunctional nanomaterials for dual-mode imaging guided cancer therapy are highly desirable in clinical applications. Herein, a flowerlike NiS₂-coated NaLuF₄:Nd (Lu:Nd@NiS₂) nanoparticle was synthesized as a novel therapeutic agent for short-wave infrared light imaging and magnetic resonance imaging to guide photothermal therapy (PTT). The material was then loaded with phenolic epigallocatechin 3-gallate (EGCG), which is a natural heat-shock protein 90 (HSP90) inhibitor. Upon near infrared irradiation, EGCG was released from the Lu:Nd@NiS₂-EGCG, which bound HSP90 and reduced cell tolerance to heat, resulting in a better therapeutic effect at the same elevated temperature. Therefore, with minimal side effects and remarkable antitumor efficacy in vivo, Lu:Nd@NiS₂-EGCG appeared to be a promising photothermal agent for enhanced PTT.

Novel near-infrared II aggregation-induced emission dots for in vivo bioimaging

Near-infrared II fluorescence imaging holds great promise for in vivo imaging and imaging-guided surgery with deep penetration and high spatiotemporal resolution. However, most NIR-II aromatic luminophores suffer from the notorious aggregation-caused quenching (ACQ) effect in the aqueous solution, which largely hinders their biomedical application in vivo. In this study, the first NIR-II organic aggregation-induced emission (AIE) fluorophore (HLZ-BTED), encapsulated as nanoparticles (HLZ-BTED dots) for in vivo biomedical imaging, was designed and synthesized. The NIR-II AIE HLZ-BTED dots showed high temporal resolution, high photostability, outstanding water-solubility and biocompatibility in vitro and in vivo. The HLZ-BTED dots were further used for long-term breast tumor imaging and visualizing tumor-feeding blood vessels, long-term hind limb vasculature and incomplete hind limb ischemia. More importantly, as a proof-of-concept, this is the first time that non-invasive and real-time NIR-II imaging of the gastrointestinal tract in health and disease has been performed, making the AIE dots a promising tool for gastrointestinal (GI) tract research, such as understanding the healthy status of GI peristalsis, diagnosing and evaluating intestinal motility dysfunction, and assessing drug effects on intestinal obstruction.

Bi2SiO5@g-SiO2 upconverting nanoparticles: a bismuth-driven core-shell self-assembly mechanism

Core-shell systems have attracted increasing interest among the research community in recent years due to their unique properties and structural features, and the development of new synthetic strategies is still a challenge. In this work, we have investigated lanthanide-doped Bi2SiO5 nanocrystal formation inside mesoporous silica nanoparticles (MSNs). The role of both synthesis temperature and concentration of the bismuth precursor impregnated into the MSNs is discussed, showing an unprecedented strategy for the simultaneous stabilization of a crystalline core and a glassy shell. Temperature dependent synchrotron radiation X-ray powder diffraction (SR-XRPD) and high resolution transmission electron microscopy (HR-TEM) analyses allow one to follow the crystalline core growth. A mechanism for the formation of a Bi2SiO5@g-SiO2 core-shell nanosystem is proposed. In addition, the easy tunability of the color output of the upconverting system is demonstrated by means of suitable doping lanthanide ions with potential applications in several fields.

Nanocellulose templated growth of ultra-small bismuth nanoparticles for enhanced radiation therapy

An unmet need in nanomedicine is to prepare biocompatible and renal clearable nanoparticles by controlling the diameter, composition and surface properties of the nanoparticles. This paper reports cellulose nanofiber templated synthesis of ultra-small bismuth nanoparticles, and their uses in enhanced X-ray radiation therapy. The interstitial spaces between adjacent fibers are the adsorption sites of bismuth ions and also stabilize nanoparticles generated by chemical reduction. The sizes of nanoparticles are tailored in the 2-10 nm range using cellulose nanofibers with various amounts of carboxyl groups. In vitro cytotoxicity, reactive oxygen species (ROS) and in vivo animal tests with tumor-bearing mice are studied in order to enhance X-ray radiation therapy using cellulose nanofiber-templated bismuth nanoparticles. Bismuth nanoparticles show strong X-ray attenuation ability, concentration-dependent cytotoxicity and high level production of ROS upon X-ray exposure, which is consistent with enhanced cellular damage and retarded growth of tumors in animals.

Deep-Level Defect Enhanced Photothermal Performance of Bismuth Sulfide-Gold Heterojunction Nanorods for Photothermal Therapy of Cancer Guided by Computed Tomography Imaging

Bismuth sulfide (Bi₂ S₃ ) nanomaterials are emerging as a promising theranostic platform for computed tomography imaging and photothermal therapy of cancer. Herein, the photothermal properties of Bi₂ S₃ nanorods (NRs) were unveiled to intensely correlate to their intrinsic deep-level defects (DLDs) that potentially could work as electron-hole nonradiative recombination centers to promote phonon production, ultimately leading to photothermal performance. Bi₂ S₃ -Au heterojunction NRs were designed to hold more significant DLD properties, exhibiting more potent photothermal performance than Bi₂ S₃ NRs. Under 808 nm laser irradiation, Bi₂ S₃ -Au NRs could trigger higher cellular heat shock protein 70 expression and more apoptotic cells than Bi₂ S₃ NRs, and caused severe cell death and tumor growth inhibition, showing great potential for photothermal therapy of cancer guided by computed tomography imaging.

Probing the modulated formation of gold nanoparticles-beta-lactoglobulin corona complexes and their applications

Understanding the interactions between proteins and nanoparticles (NPs) along with the underlying structural and dynamic information is of utmost importance to exploit nanotechnology for biomedical applications. Upon adsorption onto a NP surface, proteins form a well-organized layer, termed the corona, that dictates the identity of the NP-protein complex and governs its biological pathways. Given its high biological relevance, in-depth molecular investigations and applications of NPs-protein corona complexes are still scarce, especially since different proteins form unique corona patterns, making identification of the biomolecular motifs at the interface critical. In this work, we provide molecular insights and structural characterizations of the bio-nano interface of a popular food-based protein, namely bovine beta-lactoglobulin (β-LG), with gold nanoparticles (AuNPs) and report on our investigations of the formation of corona complexes by combined molecular simulations and complementary experiments. Two major binding sites in β-LG were identified as being driven by citrate-mediated electrostatic interactions, while the associated binding kinetics and conformational changes in the secondary structures were also characterized. More importantly, the superior stability of the corona led us to further explore its biomedical applications, such as in the smartphone-based point-of-care biosensing of Escherichia coli (E. coli) and in the computed tomography (CT) of the gastrointestinal (GI) tract through oral administration to probe GI tolerance and functions. Considering their biocompatibility, edible nature, and efficient excretion through defecation, AuNPs-β-LG corona complexes have shown promising perspectives for future in vitro and in vivo clinical settings.

Enhanced Radiotherapy using Bismuth Sulfide Nanoagents Combined with Photo-thermal Treatment

Nanotechniques that can improve the effectiveness of radiotherapy (RT) by integrating it with multimodal imaging are highly desirable. Results In this study, we fabricated Bi2S3 nanorods that have attractive features such as their ability to function as contrast agents for X-ray computed tomography (CT) and photoacoustic (PA) imaging as well as good biocompatibility. Both in vitro and in vivo studies confirmed that the Bi2S3 nanoagents could potentiate the lethal effects of radiation via amplifying the local radiation dose and enhancing the anti-tumor efficacy of RT by augmenting the photo-thermal effect. Furthermore, the nanoagent-mediated hyperthermia could effectively increase the oxygen concentration in hypoxic regions thereby inhibiting the expression of hypoxia-inducible factor (HIF-1α). This, in turn, interfered with DNA repair via decreasing the expression of DNA repair-related proteins to overcome radio-resistance. Also, RT combined with nanoagent-mediated hyperthermia could substantially suppress tumor metastasis via down-regulating angiogenic factors. Conclusion In summary, we constructed a single-component powerful nanoagent for CT/PA imaging-guided tumor radiotherapy and, most importantly, explored the potential mechanisms of nanoagent-mediated photo-thermal treatment for enhancing the efficacy of RT in a synergistic manner.

Design of TPGS-functionalized Cu3BiS3 nanocrystals with strong absorption in the second near-infrared window for radiation therapy enhancement

Integrating radiation therapy with high-depth photothermal therapy in the second near-infrared (NIR) window is highly required for efficient treatment of deep-seated tumor cells. Here, we constructed a multifunctional nano-theranostic with bimetallic chalcogenide nanocrystals (NCs) functionalized with amphiphilic d-α-tocopherol polyethylene glycol 1000 succinate (TPGS-Cu₃BiS₃). Benefiting from the strong absorbance of both X-ray and NIR light in the second NIR window, TPGS-Cu₃BiS₃ CNs can not only deposit more radiation dose to trigger enhanced radiation damage in vivo, but also conduct photo-induced hyperthermia for thermal ablation in the second NIR window and effective improvement of tumor oxygenation to overcome the hypoxia-associated radio-resistance of tumors. Moreover, copper ions on the surface of TPGS-Cu₃BiS₃ NCs are capable of catalyzing the Fenton-like and Haber-Weiss reactions to produce highly reactive hydroxyl radicals, leading to the increase in the level of oxygen radicals and further enhance cancer cell destruction. Apart from their therapeutic application, by means of X-ray computer tomography imaging as well as multispectral optoacoustic tomography imaging, TPGS-Cu₃BiS₃ NCs also have the potential as a nano-theranostic to offer remarkable therapeutic outcome for deep-seated tumor cells in imaging-guided synergistically enhanced radiation therapy.

Opportunities for new CT contrast agents to maximize the diagnostic potential of emerging spectral CT technologies

The introduction of spectral CT imaging in the form of fast clinical dual-energy CT enabled contrast material to be differentiated from other radiodense materials, improved lesion detection in contrast-enhanced scans, and changed the way that existing iodine and barium contrast materials are used in clinical practice. More profoundly, spectral CT can differentiate between individual contrast materials that have different reporter elements such that high-resolution CT imaging of multiple contrast agents can be obtained in a single pass of the CT scanner. These spectral CT capabilities would be even more impactful with the development of contrast materials designed to complement the existing clinical iodine- and barium-based agents. New biocompatible high-atomic number contrast materials with different biodistribution and X-ray attenuation properties than existing agents will expand the diagnostic power of spectral CT imaging without penalties in radiation dose or scan time.

Multifunctional Theranostic Agent of Cu2(OH)PO4 Quantum Dots for Photoacoustic Image-Guided Photothermal/Photodynamic Combination Cancer Therapy

Image-guided phototherapy is considered to be a prospective technique for cancer treatment because it can provide both oncotherapy and bioimaging, thus achieving an optimized therapeutic efficacy and higher treatment accuracy. Compared to complicated systems with multiple components, using a single material for this multifunctional purpose is preferable. In this work, we strategically fabricated poly(acrylic acid)- (PAA-) coated Cu₂(OH)PO₄ quantum dots [denoted as Cu₂(OH)PO₄@PAA QDs], which exhibit a strong near-infrared photoabsorption ability. As a result, an excellent photothermal conversion ability and the photoactivated formation of reactive oxygen species could be realized upon NIR irradiation, concurrently meeting the basic requirements for photothermal and photodynamic therapies. Moreover, phototherapeutic investigations on both cervical cancer cells in vitro and solid tumors of an in vivo mice model illustrated the effective antitumor effects of Cu₂(OH)PO₄@PAA upon 1064-nm laser irradiation, with no detectable lesions in major organs during treatment. Meanwhile, Cu₂(OH)PO₄@PAA is also an exogenous contrast for photoacoustic tomography (PAT) imaging to depict tumors under NIR irradiation. In brief, the Cu₂(OH)PO₄@PAA QDs prepared in this work are expected to serve as a multifunctional theranostic platform.

Multifunctional Theranostics for Dual-Modal Photodynamic Synergistic Therapy via Stepwise Water Splitting

Combined therapy using multiple approaches has been demonstrated to be a promising route for cancer therapy. To achieve enhanced antiproliferation efficacy under hypoxic condition, here we report a novel hybrid system by integrating dual-model photodynamic therapies (dual-PDT) in one system. First, we attached core-shell structured up-conversion nanoparticles (UCNPs, NaGdF₄:Yb,Tm@NaGdF₄) on graphitic-phase carbon nitride (g-C₃N₄) nanosheets (one photosensitizer). Then, the as-fabricated nanocomposite and carbon dots (another photosensitizer) were assembled in ZIF-8 metal-organic frameworks through an in situ growth process, realizing the dual-photosensitizer hybrid system employed for PDT via stepwise water splitting. In this system, the UCNPs can convert deep-penetration and low-energy near-infrared light to higher-energy ultraviolet-visible emission, which matches well with the absorption range of the photosensitizers for reactive oxygen species (ROS) generation without sacrificing its efficacy under ZIF-8 shell protection. Furthermore, the UV light emitted from UCNPs allows successive activation of g-C₃N₄ and carbon dots, and the visible light from carbon dots upon UV light excitation once again activate g-C₃N₄ to produce ROS, which keeps the principle of energy conservation thus achieving maximized use of the light. This dual-PDT system exhibits excellent antitumor efficiency superior to any single modality, verified vividly by in vitro and in vivo assay.

Annexin V-Conjugated Mixed Micelles as a Potential Drug Delivery System for Targeted Thrombolysis

To alleviate the hemorrhagic side effect of thrombolysis therapy, a thrombus targeted drug delivery system based on the specific affinity of Annexin V to phosphatidylserine exposed on the membrane surface of activated platelet was developed. The amphiphilic and biodegradable biomaterial, polycaprolactone-block-poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-hydroxyethyl methacrylate) (PCL-b-PDMAEMA-b-PHEMA (PCDH)) triblock polymer, was synthesized via ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP) to use as the nanocarriers of thrombolytic drug. In order to conjugate Annexin V to the polymer, PCDH was modified by succinic anhydride via ring-opening reaction to introduce the carboxyl group (PCDH-COOH). After preparation of PCDH/PCDH-COOH (9/1, m/m) mixed micelles, Annexin V was coupled with the micelles using carbodiimide chemistry. The blood clot lysis assay in vitro confirmed that lumbrokinase-loaded targeted micelles (LKTM) had stronger thrombolysis potency than free lumbrokinase (LK) and LK-loaded nontargeted micelles (LKM, P < 0.05). In vivo thrombolytic assay, multispectral, optoacoustic tomography (MSOT) was used to assess the target ability of LKTM. The results of MSOT images indicated the fluorescence intensity of the LKTM group located in the blood clot position were significantly stronger than the LKM group. A 5 mm of carotid artery containing blood clot was cut out 24 h later after administration to assess the degree of thrombolysis. The results of thrombolytic assay in vivo were consistent with the assay in vitro, which the differences between LK, LKM, and LKTM groups were both statistically significant. All the results of thrombolysis assays above proved that the capacity of thrombolysis in the LKTM group was optimal. It suggested that Annexin V-conjugated micelles will be a potential drug delivery system for targeted thrombolysis.

Chitosan coated tungsten trioxide nanoparticles as a contrast agent for X-ray computed tomography

Recent advances have shown that inorganic nanoparticles (NPs) based on heavy elements are highly appropriate for X-ray computed tomography (CT). In this contribution, tungsten trioxide NPs are prepared by the electrical arc discharge (EAD) method in DI water. The effect of chitosan (CTS) and glutaraldehyde (GTA) as coating and cross-linking agent, respectively, on the hydrodynamic size and zeta potential of prepared tungsten trioxide NPs is investigated. It is found that zeta potential increases by increasing the amounts of CTS. Meanwhile, by increasing the volume of glutaraldehyde (GTA), the final particle size increases whereas the zeta potential deceases. Chitosan coated tungsten trioxide demonstrated no significant cytotoxicity at concentration up to 5mg/mL after 24h. Finally, the X-ray attenuation of prepared chitosan coated tungsten trioxide NPs are higher than Iohexol as the commercially available iodinated contrasting agent at the same concentrations.

Protein-directed synthesis of Bi2S3 nanoparticles as an efficient contrast agent for visualizing the gastrointestinal tract

BSA@Bi₂S₃ nanoparticles can be applied for CT imaging of the gastrointestinal tract, realizing the visualization of gastrointestinal structures.

Two-dimensional transition metal dichalcogenide nanomaterials for combination cancer therapy

In this review, we mainly summarize the latest advances in the utilization of 2D TMDCs for PTT combination cancer therapy and imaging-guided cancer combination therapy, as well as their toxicity bothin vitroandin vivo.

A nanocomposite of Au-AgI core/shell dimer as a dual-modality contrast agent for x-ray computed tomography and photoacoustic imaging

PURPOSE

To develop a core/shell nanodimer of gold (core) and silver iodine (shell) as a dual-modal contrast-enhancing agent for biomarker targeted x-ray computed tomography (CT) and photoacoustic imaging (PAI) applications.

METHODS

The gold and silver iodine core/shell nanodimer (Au/AgICSD) was prepared by fusing together components of gold, silver, and iodine. The physicochemical properties of Au/AgICSD were then characterized using different optical and imaging techniques (e.g., HR- transmission electron microscope, scanning transmission electron microscope, x-ray photoelectron spectroscopy, energy-dispersive x-ray spectroscopy, Z-potential, and UV-vis). The CT and PAI contrast-enhancing effects were tested and then compared with a clinically used CT contrast agent and Au nanoparticles. To confer biocompatibility and the capability for efficient biomarker targeting, the surface of the Au/AgICSD nanodimer was modified with the amphiphilic diblock polymer and then functionalized with transferrin for targeting transferrin receptor that is overexpressed in various cancer cells. Cytotoxicity of the prepared Au/AgICSD nanodimer was also tested with both normal and cancer cell lines.

RESULTS

The characterizations of prepared Au/AgI core/shell nanostructure confirmed the formation of Au/AgICSD nanodimers. Au/AgICSD nanodimer is stable in physiological conditions for in vivo applications. Au/AgICSD nanodimer exhibited higher contrast enhancement in both CT and PAI for dual-modality imaging. Moreover, transferrin functionalized Au/AgICSD nanodimer showed specific binding to the tumor cells that have a high level of expression of the transferrin receptor.

CONCLUSIONS

The developed Au/AgICSD nanodimer can be used as a potential biomarker targeted dual-modal contrast agent for both or combined CT and PAI molecular imaging.

Facile Synthesis of Uniform-Sized Bismuth Nanoparticles for CT Visualization of Gastrointestinal Tract in Vivo

High-performance and biocompatible contrast agents are the key to accurate diagnosis of various diseases in vivo via CT imaging. Fabrication of pure Bi nanoparticles is the best way to maximize X-ray absorption efficiency due to the ultrahigh X-ray attenuation ability of Bi and 100% content of Bi element. However, high-quality Bi nanoparticles prepared through a facile strategy are still lacking. Herein, we report a simple noninjection method to fabricate uniformly sized pure Bi nanoparticles using only two commercial reagents by simply heating the mixture of raw materials in a short time. The obtained Bi nanoparticles owned highly uniform size, excellent monodispersity, and impressive antioxidant capacity. After being modified with oligosaccharide, the "sweet" Bi nanoprobe with comfortable patient experience and favorable biocompatibility was successfully used in CT visualization of gastrointestinal tract in detail.

Folate-targeted perfluorohexane nanoparticles carrying bismuth sulfide for use in US/CT dual-mode imaging and synergistic high-intensity focused ultrasound ablation of cervical cancer

The integration of multifunctional contrast agents with HIFU synergistic therapy could real-time guide, monitor, and assess cancer therapeutic procedures and effects.