Gd-encapsulated carbonaceous dots with efficient renal clearance for magnetic resonance imaging

Gadolinium Functionalized Carbon Dot Complexes for Dual-Modal Imaging: Structure, Performance, and Applications

Gadolinium functionalized carbon dot complexes (Gd-CDs) have both the fluorescent properties of carbon dots and the magnetic characteristics of gadolinium ions, exhibiting excellent biocompatibility, high spatial resolution, high sensitivity, and deep tissue penetration in bioimaging. As fluorescence (FL) and magnetic resonance imaging (MRI) probes, Gd-CDs have attracted significant attention in dual-modal biological imaging. This review summarizes recent advances in Gd-CDs, focusing on their structure, optical and magnetic properties, and applications in dual-modal imaging. First, according to the different existing forms of gadolinium in carbon dots, the structures of Gd-CDs are categorized into chelation, electrostatic interaction, and encapsulation. Second, the mechanisms and performances of Gd-CDs in dual-modal imaging are introduced in detail. The reported Gd-CDs have a maximum quantum yield of 69.86%, with a fluorescence emission wavelength reaching up to 625 nm, and the optimum longitudinal and transverse relaxivity rates are 35.39 and 115.6 mM-1 s-1, respectively, showing excellent FL/MRI capacities. Subsequently, the progress in their applications in dual-modal cellular imaging, in vivo imaging, and integrated cancer diagnosis and therapy is reviewed. Finally, the challenges and issues faced by Gd-CDs in their development are summarized, providing new insights for their controlled synthesis and widespread application in the biomedical field of dual-modal imaging.

Synthesis, MTT assay, 99m-Technetium radiolabeling, biodistribution evaluation of radiotracer and in vitro magnetic resonance imaging study of P,N-doped graphene quantum dots as a new multipurpose imaging nano-agent

In this study, a new nano-structure, N,P-doped graphene quantum dots (N,P-GQDs), were synthesized as multipurpose imaging agent for performing scintigraphy and magnetic resonance imaging (MRI). Some standard characterization methods were used to identify the nano-structure. In vitro cytotoxicity evaluation using MTT assay revealed that N,P-GQDs nanoparticles had no significant cytotoxicity after 24 and 48 h against normal (MCF-10A) and cancerous (MCF 7) human breast cell line in concentration up to 200 μg/mL. The N,P-GQDs were radiolabeled with Technetium-99m as 99mTc-(N,P-GQDs) and the radiochemical purity was assayed by ITLC concluding RCP ≥ 95 %. The passing of 99mTc-(N,P-GQDs) through 0.1 µm filter demonstrated that 70.8 % of particles were <0.1 µm. In order to perform scintigraphy, the 99mTc-(N,P-GQDs) were injected to female healthy Wistar rats. The results showed that the radio-complex was captured and eliminated just by kidneys. Moreover, in vitro T1-weighted phantom MRI imaging showed that the N,P-GQDs have proper relaxivity in comparison to Dotarem® as a clinically available contrast agent. The results showed that the N,P-GQDs have potential to be considered as a novel and encouraging agent for both molecular MRI and nuclear medicine imagings.

Gold Nanoparticle Transport in the Injured Kidneys with Elevated Renal Function Biomarkers

Renal function biomarkers such as serum blood urea nitrogen (BUN) and creatinine (Cr) serve as key indicators for guiding clinical decisions before administering kidney-excreted small-molecule agents. With engineered nanoparticles increasingly designed to be renally clearable to expedite their clinical translation, understanding the relationship between renal function biomarkers and nanoparticle transport in diseased kidneys becomes crucial to their biosafety in future clinical applications. In this study, renal-clearable gold nanoparticles (AuNPs) are used as X-ray contrast agents to noninvasively track their transport and retention in cisplatin-injured kidneys with varying BUN and Cr levels. The findings reveal that AuNP transport is significantly slowed in the medulla of severely injured kidneys, with BUN and Cr levels elevated to 10 times normal. In mildly injured kidneys, where BUN and Cr levels only four to five times higher than normal, AuNP transport and retention are not predictable by BUN and Cr levels but correlate strongly with the degree of tubular injury due to the formation of gold-protein casts in the Henle's loop of the medulla. These results underscore the need for caution when employing renal-clearable nanomedicines in compromised kidneys and highlight the potential of renal-clearable AuNPs as X-ray probes for assessing kidney injuries noninvasively.

RGD-modified ZIF-8 nanoparticles as a drug carrier for MR imaging and targeted drug delivery in myocardial infarction

Aim: A multifunctional nanoplatform has been developed to enhance the targeting capability and biosafety of drug/siRNA for better diagnosis and treatment of myocardial infarction (MI).Materials & methods: The nanoplatform's chemical properties, biodistribution, cardiac magnetic resonance imaging (MRI) capabilities, therapeutic effects and biocompatibility were investigated.Results: The nanoplatform exhibited MI-targeting properties and pH-sensitivity, allowing for effective cardiac MRI and delivery of drugs to the infarcted myocardium. The GCD/Qt@ZIF-RGD demonstrated potential as a reliable MRI probe for MI diagnosis. Moreover, the GCD/si-SHP1/Qt@ZIF-RGD effectively suppressed SHP-1 expression, increased pro-angiogenesis gene expression and reduced cell apoptosis in HUVECs exposed to hypoxia/reoxygenation.Conclusion: Our newly developed multifunctional drug delivery system shows promise as a nanoplatform for both the diagnosis and treatment of MI.

Metal-doped carbon dots for biomedical applications: From design to implementation

Carbon dots (CDs), as a new kind of fluorescent nanomaterials, show great potential for application in several fields due to their unique nano-size effect, easy surface functionalization, controllable photoluminescence, and excellent biocompatibility. Conventional preparation methods for CDs typically involve top-down and bottom-up approaches. Doping is a major step forward in CDs design methodology. Chemical doping includes both non-metal and metal doping, in which non-metal doping is an effective strategy for modulating the fluorescence properties of CDs and improving photocatalytic performance in several areas. In recent years, Metal-doped CDs have aroused the interest of academics as a promising nano-doping technique. This approach has led to improvements in the physicochemical and optical properties of CDs by altering their electron density distribution and bandgap capacity. Additionally, the issues of metal toxicity and utilization have been addressed to a large extent. In this review, we categorize metals into two major groups: transition group metals and rare-earth group metals, and an overview of recent advances in biomedical applications of these two categories, respectively. Meanwhile, the prospects and the challenges of metal-doped CDs for biomedical applications are reviewed and concluded. The aim of this paper is to break through the existing deficiencies of metal-doped CDs and fully exploit their potential. I believe that this review will broaden the insight into the synthesis and biomedical applications of metal-doped CDs.

Facile synthesis of Gd/Ru-doped fluorescent carbon dots for fluorescent/MR bimodal imaging and tumor therapy

Functional metal doping endows fluorescent carbon dots with richer physical and chemical properties, greatly expanding their potential in the biomedical field. Nonetheless, fabricating carbon dots with integrated functionality for diagnostic and therapeutic modalities remains challenging. Herein, we develop a simple strategy to prepare Gd/Ru bimetallic doped fluorescent carbon dots (Gd/Ru-CDs) via a one-step microwave-assisted method with Ru(dcbpy)3Cl2, citric acid, polyethyleneimine, and GdCl3 as precursors. Multiple techniques were employed to characterize the morphology and properties of the obtained carbon dots. The Gd/Ru-CDs are high mono-dispersity, uniform spherical nanoparticles with an average diameter of 4.2 nm. Moreover, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) confirmed the composition and surface properties of the carbon dots. In particular, the successful doping of Gd/Ru enables the carbon dots not only show considerable magnetic resonance imaging (MRI) performance but also obtain better fluorescence (FL) properties, especially in the red emission area. More impressively, it has low cytotoxicity, excellent biocompatibility, and efficient reactive oxygen species (ROS) generation ability, making it an effective imaging-guided tumor treatment reagent. In vivo experiments have revealed that Gd/Ru-CDs can achieve light-induced tumor suppression and non-invasive fluorescence/magnetic resonance bimodal imaging reagents to monitor the treatment process of mouse tumor models. Thus, this simple and efficient carbon dot manufacturing strategy by doping functional metals has expanded avenues for the development and application of multifunctional all-in-one theranostics.

Carbon Dots for Multiuse Platform: Intracellular pH Sensing and Complementary Intensified T1-T2 Dual Imaging Contrast Nanoprobes

Measurement of pH in living cells is a great and decisive factor for providing an early and accurate diagnosis factor. Along with this, the multimodal transverse and longitudinal relaxivity enhancement potentiality over single modality within a single platform in the magnetic resonance imaging (MRI) field is a very challenging issue for diagnostic purposes in the biomedical field of application. Therefore, this work aims to design a versatile platform by fabricating a novel nanoprobe through holmium- and manganese-ion doping in carbon quantum dots (Ho-Mn-CQDs), which can show nearly neutral intracellular pH sensing and MRI imaging at the same time. These manufactured Ho-Mn-CQDs acted as excellent pH sensors in the near-neutral range (4.01-8.01) with the linearity between 6.01 and 8.01, which could be useful for the intracellular pH-sensing capability. An innumerable number of carboxyl and amino groups are present on the surface of the prepared nanoprobe, making it an excellent candidate for pH sensing through fluorescence intensity quenching phenomena. Cellular uptake and cell viability experiments were also executed to affirm the intracellular accepting ability of Ho-Mn-CQDs. Furthermore, with this pH-sensing quality, these Ho-Mn-CQDs are also capable of acting as T1-T2 dual modal imaging contrast agents in comparison with pristine Ho-doped and Mn-doped CQDs. The Ho-Mn-CQDs showed an increment of r1 and r2 relaxivity values simultaneously compared with only the negative contrast agent, holmium in holmium-doped CQDs, and the positive contrast agent, manganese in manganese-doped CQDs. The above-mentioned observations elucidate that its tiny size, excitation dependence of fluorescence behavior, low cytotoxicity, and dual modal contrast imaging capability make it an ideal candidate for pH monitoring in the near-neutral range and also as a dual modal MRI imaging contrast enhancement nanoprobe at the same time.

Folic acid functionalized gadolinium-doped carbon dots as fluorescence / magnetic resonance imaging contrast agent for targeted imaging of liver cancer

Gadolinium-doped carbon dots (Gd-CDs), as a new class of nanomaterial, has a wide application prospect in targeted imaging and monitoring diagnosis and treatment of liver cancer because of their good fluorescence (FL)-magnetic resonance (MR) imaging properties. First, Gd-CDs were synthesized by hydrothermal method with gadodiamide as gadolinium source, citric acid as carbon source and silane coupling agent (KH-792) as coupling agent with FL quantum yield (QY) of 48.2%. Then, folic acid (FA), which is highly expressed in liver cancer, was used as a targeting component to modify Gd-CDs to obtain targeted imaging agent (Gd-CDs-FA). The results showed that Gd-CDs and Gd-CDs-FA have low cytotoxicity and good biocompatibility, and the targeting and selectivity of Gd-CDs-FA to HepG2 cells could be observed under confocal laser scanning microscope (CLSM). The T1 longitudinal relaxation rates (r1) of Gd-CDs and Gd-CDs-FA are 15.92 mM-1s-1 and 13.56 mM-1s-1, respectively. They showed good MR imaging ability in vitro and in vivo, and MR imaging in nude mice further proved the targeting imaging performance of Gd-CDs-FA. Therefore, Gd-CDs-FA with higher QY showed good FL-MR targeting imaging ability of liver cancer, which broke through the limitations of single molecular imaging probe in sensitivity and soft tissue resolution. This study provides a new idea for the application of Gd-CDs in FL and MR targeting imaging of liver cancer.

Multifunctional Carbon Dots for Biomedical Applications: Diagnosis, Therapy, and Theranostic

Designing suitable nanomaterials is an ideal strategy to enable early diagnosis and effective treatment of diseases. Carbon dots (CDs) are luminescent carbonaceous nanoparticles that have attracted considerable attention. Through facile synthesis, they process properties including tunable light emission, low toxicity, and light energy transformation, leading to diverse applications as optically functional materials in biomedical fields. Recently, their potentials have been further explored, such as enzyme-like activity and ability to promote osteogenic differentiation. Through refined synthesizing strategies carbon dots, a rich treasure trove for new discoveries, stand a chance to guide significant development in biomedical applications. In this review, the authors start with a brief introduction to CDs. By presenting mechanisms and examples, the authors focus on how they can be used in diagnosing and treating diseases, including bioimaging failure of tissues and cells, biosensing various pathogenic factors and biomarkers, tissue defect repair, anti-inflammation, antibacterial and antiviral, and novel oncology treatment. The introduction of the application of integrated diagnosis and treatment follows closely behind. Furthermore, the challenges and future directions of CDs are discussed. The authors hope this review will provide critical perspectives to inspire new discoveries on CDs and prompt their advances in biomedical applications.

Renal clearable magnetic nanoparticles for magnetic resonance imaging and guided therapy

Magnetic resonance imaging (MRI) is a non-invasive, radiation-free imaging technique widely used for disease detection and therapeutic evaluation due to its infinite penetration depth. Magnetic nanoparticles (MNPs) have unique magnetic and physicochemical properties, making them ideal as contrast agents for MRI. However, the in vivo toxicity of MNPs, resulting from metal ion leakage and long-term accumulation in the reticuloendothelial system (RES), limits their clinical application. To overcome these challenges, there is considerable interest in the development of renal-clearable MNPs that can be completely cleared through the kidney, reducing retention time and potential toxic risks. In this review, we provide an overview of recent advancements in the development of renal-clearable MNPs for disease imaging and treatment. We discuss the factors influencing renal clearance, summarize the types of renal-clearable MNPs, their synthesis methods, and biomedical applications. This review aims to offer comprehensive information for the design and clinical translation of renal-clearable MNPs. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Biosensing.

Polyoxometalates as Potential Artificial Enzymes toward Biological Applications

Artificial enzymes, as alternatives to natural enzymes, have attracted enormous attention in the fields of catalysis, biosensing, diagnostics, and therapeutics because of their high stability and low cost. Polyoxometalates (POMs), a class of inorganic metal oxides, have recently shown great potential in mimicking enzyme activity due to their well-defined structure, tunable composition, high catalytic efficiency, and easy storage properties. This review focuses on the recent advances in POM-based artificial enzymes. Different types of POMs and their derivatives-based mimetic enzyme functions are covered, as well as the corresponding catalytic mechanisms (where available). An overview of the broad applications of representative POM-based artificial enzymes from biosensing to theragnostic is provided. Insight into the current challenges and the future directions for POMs-based artificial enzymes is discussed.

Advances in Magnetic Carbon Dots: A Theranostics Platform for Fluorescence/Magnetic Resonance Bimodal Imaging and Therapy for Tumors

Theranostics technology that combines tumor diagnosis or monitoring with therapy is an important direction for the future development of tumor treatment. It takes advantage of efficiently observing tumor tissues, monitoring tumor treatment in real time, and significantly improving the cure efficiency. Magnetic carbon dots (CDs) are of wide interest as molecular imaging probes, drug carriers, photosensitizers, and radiosensitizers in the integration of tumor fluorescence/magnetic resonance bimodal diagnosis and treatment because of their small size, good optical stability, magnetic relaxation rate, and biocompatibility. This review first analyzes and compares the synthesis methods and physicochemical properties of magnetic CDs in recent years and then concludes their mechanism in tumor fluorescence/magnetic resonance bimodal imaging and therapy in details. Subsequently, the research progress of their application in tumor theranostics are summarized. Finally, the problems and challenges of magnetic CDs for development at this stage are prospected. This review provides new ideas for their controlled synthesis and application in efficient and precise therapy for tumors.

VEGF mimetic peptide-conjugated nanoparticles for magnetic resonance imaging and therapy of myocardial infarction

To reduce the mortality of myocardial infarction (MI), accurate detection of the infarct and appropriate prevention against ischemia/reperfusion (I/R) induced cardiac dysfunction are highly desired. Considering that vascular endothelial growth factor (VEGF) receptors are overexpressed in the infarcted heart and VEGF mimetic peptide QK binds specifically to VEGF receptors and activates vascularization, the PEG-QK-modified, gadolinium-doped carbon dots (GCD-PEG-QK) were formulated. This research aims to investigate the magnetic resonance imaging (MRI) capability of GCD-PEG-QK on myocardial infarct and their therapeutic effect on I/R-induced myocardial injury. These multifunctional nanoparticles exhibited good colloidal stability, excellent fluorescent and magnetic property, and satisfactory biocompatibility. Intravenous injection of GCD-PEG-QK nanoparticles post myocardial I/R displayed accurate MRI of the infarct, enhanced efficacy of QK peptide on pro-angiogenesis, and amelioration of cardiac fibrosis, remodeling and dysfunction, probably via the improvement on QK's in vivo stability and MI-targeting. Collectively, the data suggested that this theranostic nanomedicine can realize precise MRI and effective therapy for acute MI in a non-invasive manner.

A comparative multi-level toxicity assessment of carbon-based Gd-free dots and Gd-doped nanohybrids from coffee waste: hematology, biochemistry, histopathology and neurobiology study

Here, a comparative toxicity assessment of precursor carbon dots from coffee waste (cofCDs) obtained using green chemistry principles and Gd-doped nanohybrids (cofNHs) was performed using hematological, biochemical, histopathological assays in vivo (CD1 mice, intraperitoneal administration, 14 days), and neurochemical approach in vitro (rat cortex nerve terminals, synaptosomes). Serum biochemistry data revealed similar changes in cofCDs and cofNHs-treated groups, i.e. no changes in liver enzymes' activities and creatinine, but decreased urea and total protein values. Hematology data demonstrated increased lymphocytes and concomitantly decreased granulocytes in both groups, which could evidence inflammatory processes in the organism and was confirmed by liver histopathology; decreased red blood cell-associated parameters and platelet count, and increased mean platelet volume, which might indicate concerns with platelet maturation and was confirmed by spleen histopathology. So, relative safety of both cofCDs and cofNHs for kidney, liver and spleen was shown, whereas there were concerns about platelet maturation and erythropoiesis. In acute neurotoxicity study, cofCDs and cofNHs (0.01 mg/ml) did not affect the extracellular level of L-[14C]glutamate and [3H]GABA in nerve terminal preparations. Therefore, cofNHs demonstrated minimal changes in serum biochemistry and hematology assays, had no acute neurotoxicity signs, and can be considered as perspective biocompatible non-toxic theragnostic agent.

Targeted nanotherapy for kidney diseases: a comprehensive review

Kidney diseases represent a major public health problem, affecting millions of people worldwide. Moreover, the treatment of kidney diseases is burdened by the problematic effects of conventional drug delivery, such as systemic drug toxicity, rapid drug clearance, and the absence of precise targeting of the kidney. Although the use of nanotechnology in medicine is in its early stage and lacks robust translational studies, nanomedicines have already shown great promise as novel drug-delivery systems for the treatment of kidney disease. On the basis of our current knowledge of renal anatomy and physiology, pathophysiology of kidney diseases, and physicochemical characteristics of nanoparticles, an expansive repertoire and wide use of nanomedicines could be developed for kidney diseases in the near future. Some limitations have slowed the transition of these agents from preclinical studies to clinical trials, however. In this review, we summarize the current knowledge on renal drug-delivery systems and recent advances in renal cell targeting; we also demonstrate their important potential as future paradigm-shifting therapies for kidney diseases.

Recent progress of emitting long-wavelength carbon dots and their merits for visualization tracking, target delivery and theranostics

As a novel strategy for in vivo visualization tracking and monitoring, carbon dots (CDs) emitting long wavelengths (LW, 600-950 nm) have received tremendous attention due to their deep tissue penetration, low photon scattering, satisfactory contrast resolution and high signal-to-background ratios. Although, the mechanism of CDs emitting LW remains controversial and what properties are best for in vivo visualization have not been specifically elucidated, it is more conducive to the in vivo application of LW-CDs through rational design and ingenious synthesis based on the appreciation of the luminescence mechanism. Therefore, this review analyzes the current tracer technologies applied in vivo and their advantages and disadvantages, with emphasis on the physical mechanism of emitting LW fluorescence for in vivo imaging. Subsequently, the general properties and merits of LW-CDs for tracking and imaging are summarized. More importantly, the factors affecting the synthesis of LW-CDs and its luminescence mechanism are highlighted. Simultaneously, the application of LW-CDs for disease diagnosis, integration of diagnosis and therapy are summarized. Finally, the bottlenecks and possible future directions of LW-CDs in visualization tracking and imaging in vivo are detailly discussed.

Single-Atom Gadolinium Nano-Contrast Agents with High Stability for Tumor T1 Magnetic Resonance Imaging

Gadolinium chelates for tumor magnetic resonance imaging (MRI) face challenges such as inadequate sensitivity, lack of selectivity, and risk of Gd leakage. This study presents a single-atom Gd nano-contrast agent (Gd-SA) that enhances tumor MRI. Isolated Gd atoms coordinated by six N atoms and two O atoms are atomically dispersed on a hollow carbon nanosphere, allowing the maximum utilization of Gd atoms with reduced risk of toxic Gd ion leakage. Owning to the large surface area and fast exchange of relaxed water molecules, Gd-SA shows excellent T₁-weighted magnetic resonance enhancement with a r₁ value of 11.05 mM^-1 s^-1 at 7 T, which is 3.6 times that of the commercial gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). In vivo MRI results show that the Gd-SA has a higher spatial resolution and a wider imaging time window for tumors than Gd-DTPA, with low hematological, hepatic, and nephric toxicities. These advantages demonstrate the great potential of single-atom Gd-based nanomaterials as safe, efficient, and long-term MRI contrast agents for cancer diagnosis.

A smartphone-based fluorospectrophotometer and ratiometric fluorescence nanoprobe for on-site quantitation of pesticide residue

Cost-effective and user-friendly quantitation at points-of-need plays an important role in food safety inspection, environmental monitoring, and biomedical analysis. This study reports a stand-alone smartphone-based fluorospectrophotometer (the SBS) installed with a custom-designed application (the SBS-App) for on-site quantitation of pesticide using a ratiometric sensing scheme. The SBS can collect fluorescence emission spectra in the wavelength range of 380-760 nm within 5 s. A ratiometric fluorescence probe is facilely prepared by directly mixing the blue-emissive carbon nanodots (the Fe3+-specific fluorometric indicator) and red-emissive quantum dots (the internal standard) at a ratio of 11.6 (w/w). Based on the acetylcholinesterase/choline oxidase dual enzyme-mediated cascade catalytic reactions of Fe2+/Fe3+ transformation, a ratiometric fluorescence sensing scheme is developed. The practicability of the SBS is validated by on-site quantitation of chlorpyrifos in apple and cabbage with a comparable accuracy to the GC-MS method, offering a scalable solution to establish a cost-effective surveillance system for pesticide pollution.

Synthesis and characterization of Gd3+-loaded hyaluronic acid-polydopamine nanoparticles as a dual contrast agent for CT and MRI scans

Magnetic resonance imaging and computed tomography (CT) suffer from low contrast sensitivity and potential toxicity of contrast agents. To overcome these limitations, we developed and tested a new class of dual contrast agents based on polydopamine nanoparticles (PDA-NPs) that are functionalized and targeted with hyaluronic acid (HA). These nanoparticles (NPs) are chelated with Gd³⁺ to provide suitable contrast. The targeted NPs were characterized through ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), infrared Fourier transform (FTIR), and dynamic light scattering (DLS). The cytotoxicity was investigated on HEK293 cells using an MTT assay. The contrast property of synthesized Gd³⁺/PDA/HA was compared with Barium sulfate and Dotarem, as commercial contrast agents (CAs) for CT and MRI, respectively. The results illustrated that synthesized PDA-NPs have a spherical morphology and an average diameter of 72 nm. A distinct absorption peak around 280 nm in the UV-vis spectrum reported the self-polymerization of PDA-NPs. The HA coating on PDA-NPs was revealed through a shift in the FTIR peak of C=O from 1618 cm^-1 to 1635 cm^-1. The Gd³⁺ adsorption on PDA/HA-NPs was confirmed using an adsorption isotherm assay. The developed CA showed low in vitro toxicity (up to 158.98 µM), and created a similar contrast in MRI and CT when compared to the commercial agents. The r₁ value for PDA/HA/Gd³⁺ (6.5 (mg/ml)^-1 s^-1) was more than Dotarem (5.6 (mg/ml)^-1 s^-1) and the results of the hemolysis test showed that at concentrations of 2, 4, 6, and 10 mg/ml, the hemolysis rate of red blood cells is very low. Additionally, the results demonstrated that PDA/HA/Gd³⁺ could better target the CD₄₄⁺-expressing cancer cells than PDA/Gd³⁺. Thus, it can be concluded that lower doses of developed CA are needed to achieve similar contrast of Dotarem, and the developed CA has no safety concerns in terms of hemolysis. The stability of PDA/HA/Gd³⁺ has also been evaluated by ICP-OES, zeta potential, and DLS during 3 days, and the results suggested that Gd-HA NPs were stable.

Multifunctional 3D-printed bioceramic scaffolds: Recent strategies for osteosarcoma treatment

Osteosarcoma is the most prevalent bone malignant tumor in children and teenagers. The bone defect, recurrence, and metastasis after surgery severely affect the life quality of patients. Clinically, bone grafts are implanted. Primary bioceramic scaffolds show a monomodal osteogenesis function. With the advances in three-dimensional printing technology and materials science, while maintaining the osteogenesis ability, scaffolds become more patient-specific and obtain additional anti-tumor ability with functional agents being loaded. Anti-tumor therapies include photothermal, magnetothermal, old and novel chemo-, gas, and photodynamic therapy. These strategies kill tumors through novel mechanisms to treat refractory osteosarcoma due to drug resistance, and some have shown the potential to reverse drug resistance and inhibit metastasis. Therefore, multifunctional three-dimensional printed bioceramic scaffolds hold excellent promise for osteosarcoma treatments. To better understand, we review the background of osteosarcoma, primary 3D-printed bioceramic scaffolds, and different therapies and have a prospect for the future.

Emerging metal doped carbon dots for promising theranostic applications

As a bridge between organic fluorophores and inorganic quantum dots, carbon dots (CDs) have been recognized as emerging nanotheranostics for biomedical applications owing to their distinctive merits such as superior optical properties, flexible modification, adjustable functionalities, and remarkable photoactive therapeutic outcome, etc. Compared to metal free CDs, the introduction of metal ion in CDs endowed metal-doped CDs (MCDs) with tunable optical properties and new intrinsic properties, thereby illustrating its different capabilities from metal-free CDs for bioimaging and therapy. This review aims to summarize the recent progress of photonic MCDs as emerging nanoagent for theranostic application such as disease-related diagnostic (involving biosensing and bioimaging) and cancer therapy. The challenges and potential development of MCDs in nanotheranostic fields are also discussed.

Recent Developments in Heteroatom/Metal-Doped Carbon Dot-Based Image-Guided Photodynamic Therapy for Cancer

Carbon nanodots (CNDs) are advanced nanomaterials with a size of 2-10 nm and are considered zero-dimensional carbonaceous materials. CNDs have received great attention in the area of cancer theranostics. The majority of review articles have shown the improvement of CNDs for use in cancer therapy and bioimaging applications. However, there is a minimal number of consolidated studies on the currently developed doped CNDs that are used in various ways in cancer therapies. Hence, in this review, we discuss the current developments in different types of heteroatom elements/metal ion-doped CNDs along with their preparations, physicochemical and biological properties, multimodal-imaging, and emerging applications in image-guided photodynamic therapies for cancer.

Calcium and phosphorus co-doped carbon dots enhance osteogenic differentiation for calvarial defect repairin situ

Calvarial bone defect remains a clinical challenge due to the lack of efficient osteo-inductive agent. Herein, a novel calcium and phosphorus codoped carbon dot (Ca/P-CD) for bone regeneration was synthesized using phosphoethanolamine and calcium gluconate as precursors. The resultant Ca/P-CDs exhibited ultra-small size, stable excitation dependent emission spectra and favorable dispersibility in water. Moreover, Ca/P-CDs with good biocompatibility rapidly entered the cytoplasm through endocytosis and increased the expression of bone differentiation genes. After mixing with temperature-sensitive hydrogel, Ca/P-CDs were injectedin situinto calvarial defect and promoted the repair of bone injury. These Ca/P-CDs provide a new treatment method for the bone repair and should be expended the application in the biomedical fields.

Carbonized paramagnetic complexes of Mn (II) as contrast agents for precise magnetic resonance imaging of sub-millimeter-sized orthotopic tumors

Paramagnetic complexes containing gadolinium ions have been widely used for magnetic resonance imaging (MRI) in clinic. However, these paramagnetic complexes pose some safety concerns. There is still a demand for the development of stable MRI contrast agents that exhibit higher sensitivity and superior functionality to existing contrast agents. Here, we develop carbonized paramagnetic complexes of manganese (II) (Mn@CCs) to encapsulate Mn2+ in sealed carbonized shells with superhigh r1 relaxivity. Compared to the most common clinical contrast agent Magnevist, investigations in vivo demonstrate that the Mn@CCs cross the intact blood-brain barrier of normal health mice with minor metal deposition; preferentially target the glioma tissues distribute homogeneously with high penetration in an intracranial mouse model; delineate clear tumor margins in MRIs of ultrasmall single-nodule brain tumors, and multi-nodular liver tumors. The sensitivity, accuracy and low toxicity offer by Mn@CCs provides new opportunities for early molecular diagnostics and imaging-guided biomedical applications.

Tannin-Mn coordination polymer coated carbon quantum dots nanocomposite for fluorescence and magnetic resonance bimodal imaging

The MR/FI bimodal imaging has attracted widely studied due to combining the advantages of MRI and FI can bridge gaps in sensitivity and depth between these two modalities. Herein, a novel MR/FI bimodal imaging probe is facile fabricated by coating the Mn-phenolic coordination polymer on the surface of the carbon quantum dots. The structure of the as-prepared nanocomposite probe is carefully validated via SEM, TEM, and XPS. The content of Mn²⁺ is calculated through the EDS and TGA. The quantum yield (QY) and emission wavelength of the probe are about 7.24% and 490 nm, respectively. The longitudinal r1 value (2.43 mM^-1 s^-1) with low r2/r1 (4.45) of the probe is obtained. Subsequently, fluorescence and MR imaging are performed. The metabolic pathways in vivo are inferred by studying the bio-distribution of the probe in major organs. Thus, these results indicate that probe would be an excellent dual-modal imaging probe for enhanced MR imaging and fluorescence imaging. MR/FI bimodal imaging probe is built via in-situ coated Mn-phenolic coordination polymer on the surface of the carbon quantum dots. The in vitro and vivo image property of the probe is evaluated.

In Vivo Biodistribution, Clearance, and Biocompatibility of Multiple Carbon Dots Containing Nanoparticles for Biomedical Application

Current research on the use of carbon dots for various biological systems mainly focuses on the single carbon dots, while particles that contain multiple carbon dots have scarcely been investigated. Here, we assessed multiple carbon dots-crosslinked polyethyleneimine nanoparticles (CDs@PEI) for their in vivo biodistribution, clearance, biocompatibility, and cellular uptake. The in vivo studies demonstrate three unique features of the CDs@PEI nanoparticles: (1) the nanoparticles possess tumor-targeting ability with steady and prolonged retention time in the tumor region. (2) The nanoparticles show hepatobiliary excretion and are clear from the intestine in feces. (3) The nanoparticles have much better biocompatibility than the polyethyleneimine passivated single carbon dots (PEI-CD). We also found that pegylated CDs@PEI nanoparticles can be effectively taken up by the cells, which the confocal laser scanning microscope can image under different excitation wavelengths (at 405, 488, and 800 nm). These prior studies provide invaluable information and new opportunities for this new type of intrinsic photoluminescence nanoparticles in carbon dot-based biomedical applications.

Simple and facile carbon dots based electrochemical biosensor for TNF-α targeting in cancer patient's sample

Tumour Necrosis Factor (TNF-α) is a pro-inflammatory cytokine having key roles in cell death, differentiation, survival, proliferation, migration and is a modulator of immune system. Therefore, TNF-α is an ideal biomarker for several disease diagnosis including cancer. However, out of all the biomarkers of cancer, TNF-α) is less explored for cancer detection. Only a few reports are available of developing biosensors for TNF-α targeting in human serum samples. Also, Carbon Dots (CDs) remains less explored in biosensor application. In this regard, for the first time, a sensitive and low-cost electrochemical biosensor based on CDs has developed. CDs were synthesized by simple yet facile microwave pyrolysis. Poly methyl methacrylate (PMMA) was selected as the matrix to hold CDs to fabricate the biosensing platform. This novel CD-PMMA nanocomposite featuring excellent biocompatibility, exceptional electrocatalytic conductivity, and large surface area. CD-PMMA was applied as transducing material to efficiently conjugate antibodies specific towards TNF-α and fabricate electrochemical immunosensor for specific detection of TNF-α. The fabricated immunosensor was used for the detection of TNF-α within a wide dynamic range of 0.05-160 pg mL^-1 with a lower detection limit of 0.05 pg mL^-1 and sensitivity of 5.56 pg mL^-1 cm^-2. Furthermore, this CDs based immunosensor retains high sensitivity, selectivity, and stability. This immunosensor demonstrated a high correlation with the conventional technique, Enzyme-Linked Immunosorbent Assay for early screening of cancer patient serum samples.

Image-guided selection of Gd@C-dots as sensitizers to improve radiotherapy of non-small cell lung cancer

BACKGROUND

Recently, gadolinium-intercalated carbon dots (Gd@C-dots) have demonstrated potential advantages over traditional high-Z nanoparticles (HZNPs) as radiosensitizers due to their high stability, minimal metal leakage, and remarkable efficacy.

RESULTS

In this work, two Gd@C-dots formulations were fabricated which bore carboxylic acid (CA-Gd@C-dots) or amino group (pPD-Gd@C-dots), respectively, on the carbon shell. While it is critical to develop innovative nanomateirals for cancer therapy, determining their tumor accumulation and retention is equally important. Therefore, in vivo positron emission tomography (PET) was performed, which found that 64Cu-labeled pPD-Gd@C-dots demonstrated significantly improved tumor retention (up to 48 h post injection) compared with CA-Gd@C-dots. Indeed, cell uptake of 64Cu-pPD-Gd@C-dots reached close to 60% of total dose compared with ~ 5% of 64Cu-CA-Gd@C-dots. pPD-Gd@C-dots was therefore further evaluated as a new radiosensitizer for non-small cell lung cancer treatment. While single dose radiation plus intratumorally injected pPD-Gd@C-dots did lead to improved tumor suppression, the inhibition effect was further improved with two doses of radiation. The persistent retention of pPD-Gd@C-dots in tumor region eliminates the need of reinjecting radiosensitizer for the second radiation.

CONCLUSIONS

PET offers a simple and straightforward way to study nanoparticle retention in vivo, and the selected pPD-Gd@C-dots hold great potential as an effective radiosensitizer.

Red Fluorescent Emissive Gd-Phenolic Nanoparticles for In Vivo Fluorescence and Magnetic Resonance Bimodal Imaging

Due to the combination of the high resolution of fluorescence imaging and the no limitation in penetration depth of magnetic resonance imaging, dual-mode imaging of magnetic resonance and fluorescence (MR/FI) have attracted extensive research in recent years. Herein, a novel MR/FI bimodal imaging probe is facile fabricated by attaching the rhodamine fluorophore covalently to the surface of the Gd-phenolic coordination polymer nanoparticles. The contents of Gd³⁺ and RB of the as prepared probe are calculated to be 8.2% and 12.5%. The quantum yield of the probe is about 8.84% as well as red fluorescent emissive. The longitudinal r1 value is 6.94 mM^-1 s^-1 and the ratio r2/r1 is very low and about 1.22. Subsequently, the and MR imaging and fluorescence both in vitro and In Vivo are performed. The metabolic pathways In Vivo are inferred by studying the bio-distribution of the probe in major organs. The as-prepared probe exhibits excellent imaging performance and biocompatibility, which is conducive to its further application.

Ultrasmall Gd@Cdots as a radiosensitizing agent for non-small cell lung cancer

High-Z nanoparticles (HZNPs) afford high cross-section for high energy radiation and have attracted wide attention as a novel type of radiosensitizer. However, conventional HZNPs are often associated with issues such as heavy metal toxicity, suboptimal pharmacokinetics, and low cellular uptake. Herein, we explore gadolinium-intercalated carbon dots (Gd@Cdots) as a dose-modifying agent for radiotherapy. Gd@Cdots are synthesized through a hydrothermal reaction with an ultrasmall size (∼3 nm) and a high Gd content. Gd@Cdots can significantly increase hydroxyl radical production under X-ray irradiation; this is attributed to not only the photoelectric effects of Gd, but also the surface catalytic effects of carbon. Because carbon is biologically and chemically inert, Gd@Cdots show low Gd leakage and minimal toxicity. In vitro studies confirm that Gd@Cdots can efficiently enhance radiation-induced cellular damage, causing elevated double strand breaks, lipid peroxidation, and mitochondrial depolarization. When tested in mice bearing non-small cell lung cancer H1299 tumors, intravenously injected Gd@Cdots plus radiation leads to improved tumor suppression and animal survival relative to radiation alone while causing no detectable toxicity. Our studies suggest a great potential of Gd@Cdots as a safe and efficient radiosensitizer.

Development of FL/MR dual-modal Au nanobipyramids for targeted cancer imaging and photothermal therapy

Multifunctional nanodrugs have emerged as an effective platform to integrate multiple imaging and therapeutic functions for tremendous biomedical applications. However, the development of a simple potent theranostic nanoplatform is still an intractable challenge. Herein, a novel theranostic nanoplatform was developed by coupling prepared Au nanobipyramids with Gd₂O₃, Au nanoclusters and denatured bovine serum albumin (AuNBP-Gd₂O₃/Au-dBSA) for FL/MR dual-modal imaging guided photothermal therapy. AS1411 aptamers were conjugated to enhance its targetability towards breast cancer. The AS1411-AuNBP-Gd₂O₃/Au-dBSA suspension could be readily heated above 40 °C at a low concentration (2 mg/L) and NIR density (1 W/cm²). The AS1411-AuNBP-Gd₂O₃/Au-dBSA revealed a fluorescence quantum yield of 4.2% and higher longitudinal relaxivity rate of 6.75 mM^-1 s^-1 compared to Gd-DTPA of 4.45 mM^-1 s^-1. As a result, the AS1411-AuNBP-Gd₂O₃/Au-dBSA functions as a multimodal nanoprobe of photothermal, fluorescence and MR imaging for specific tumor diagnosis and guidance of therapy, which was validated via in vitro and in vivo tests. Moreover, AS1411-AuNBP-Gd₂O₃/Au-dBSA nanoparticles indicated excellent photothermal anticancer effect more than 95% in both in vitro and in vivo tests. Besides, the low toxicity of AS1411-AuNBP-Gd₂O₃/Au-dBSA nanocomposites was further confirmed in vitro and in vivo. Thus, these results demonstrated the AS1411-AuNBP-Gd₂O₃/Au-dBSA nanocomposites as a rational design of multifunctional nanoplatform to enable multimodal imaging guided photothermal therapy.

Single-Atom Gadolinium Anchored on Graphene Quantum Dots as a Magnetic Resonance Signal Amplifier

A single-atom metal doped on carbonaceous nanomaterials has attracted increasing attention due to its potential applications as high-performance catalysts. However, few studies focus on the applications of such nanomaterials as nanotheranostics for simultaneous bioimaging and cancer therapy. Herein, it is pioneeringly demonstrated that the single-atom Gd anchored onto graphene quantum dots (SAGd-GQDs), with dendrite-like morphology, was successfully prepared. More importantly, the as-fabricated SAGd-GQDs exhibits a robustly enhanced longitudinal relaxivity (r₁ = 86.08 mM^-1 s^-1) at a low Gd³⁺ concentration of 2 μmol kg^-1, which is 25 times higher than the commercial Gd-DTPA (r₁ = 3.44 mM^-1 s^-1). In vitro and in vivo studies suggest that the obtained SAGd-GQDs is a highly potent and contrast agent to obtain high-definition MRI, thereby opening up more opportunities for future precise clinical theranostics.

Manganese-nitrogen and gadolinium-nitrogen Co-doped graphene quantum dots as bimodal magnetic resonance and fluorescence imaging nanoprobes

Graphene quantum dots (GQDs) are unique derivatives of graphene that show promise in multiple biomedical applications as biosensors, bioimaging agents, and drug/gene delivery vehicles. Their ease in functionalization, biocompatibility, and intrinsic fluorescence enable those modalities. However, GQDs lack deep tissue magnetic resonance imaging (MRI) capabilities desirable for diagnostics. Considering that the drawbacks of MRI contrast agent toxicity are still poorly addressed, we develop novel Mn²⁺ or Gd³⁺ doped nitrogen-containing graphene quantum dots (NGQDs) to equip the GQDs with MRI capabilities and at the same time render contrast agents biocompatible. Water-soluble biocompatible Mn-NGQDs and Gd-NGQDs synthesized via single-step microwave-assisted scalable hydrothermal reaction enable dual MRI and fluorescence modalities. These quasi-spherical 3.9-6.6 nm average-sized structures possess highly crystalline graphitic lattice structure with 0.24 and 0.53 atomic % for Mn²⁺ and Gd³⁺ doping. This structure ensures high in vitro biocompatibility of up to 1.3 mg ml^-1 and 1.5 mg ml^-1 for Mn-NGQDs and Gd-NGQDs, respectively, and effective internalization in HEK-293 cells traced by intrinsic NGQD fluorescence. As MRI contrast agents with considerably low Gd and Mn content, Mn-NGQDs exhibit substantial transverse/longitudinal relaxivity (r ₂/r ₁) ratios of 11.190, showing potential as dual-mode longitudinal or transverse relaxation time (T ₁ or T ₂) contrast agents, while Gd-NGQDs possess r ₂/r ₁ of 1.148 with high r ₁ of 9.546 mM^-1 s^-1 compared to commercial contrast agents, suggesting their potential as T1 contrast agents. Compared to other nanoplatforms, these novel Mn²⁺ and Gd³⁺ doped NGQDs not only provide scalable biocompatible alternatives as T1/T2 and T1 contrast agents but also enable in vitro intrinsic fluorescence imaging.

Fluorescence quenching mechanism and the application of green carbon nanodots in the detection of heavy metal ions: a review

This review article highlights the quenching mechanism and applications of green CNDs for the detection of metal ions.

Development of fluorescence/MR dual-modal manganese-nitrogen-doped carbon nanosheets as an efficient contrast agent for targeted ovarian carcinoma imaging

Background

Development of sensitive and specific imaging approaches for the detection of ovarian cancer holds great promise for improving the therapeutic efficacy and the lifespan of the patients.

Results

In this study, manganese-nitrogen doped carbon nanosheets (Mn-N-CNSs) coupled with Anti-HE4 monoclonal antibody (Mn-N-CNSs@Anti-HE4) were synthesized for the specific and targeted fluorescence/MR dual-modal imaging of ovarian carcinoma. The prepared Mn-N-CNSs revealed excellent aqueous dispersity, good colloidal stability, great optical properties and high longtudinal relaxivity rate (r₁ = 10.30 mM⁻¹ s⁻¹). Encouraged by the tunable photoluminiscence of the nanoprobe and Anti-HE4 targeting ligand, the ovarian carcinoma cells were specifically labeled by the Mn-N-CNSs@Anti-HE4 nanoprobe with multi-color fluorescences. Benefiting from the high r₁ relaxivity, the nanoprobe exhibited targeted and enhanced MR contrast effect in the ovarian carcinoma cells and tumor bearing mice model. Besides, the high biocompatibility and easy excretion from the body of the nanoprobe were further confirmed in vivo.

Conclusion

The prepared Mn-N-CNSs@Anti-HE4 with excellent biocompatibility, high-performance and superior tumor-targeting ability provides a novel fluorescence/MR dual-modal nanoprobe for specific labeling and detection of ovarian carcinoma cells in vitro and in vivo.

Tunable NIR-II emitting silver chalcogenide quantum dots using thio/selenourea precursors: preparation of an MRI/NIR-II multimodal imaging agent

Aqueous-stable, Cd- and Pb-free colloidal quantum dots with fluorescence properties in the second near-infrared region (NIR-II, 1000-1400) are highly desirable for non-invasive deep-tissue optical imaging and biosensing. The low band-gap semiconductor, silver chalcogenide, offers a non-toxic and stable alternative to existing Pd, As, Hg and Cd-based NIR-II colloidal quantum dots (QDs). We report facile access to NIR-II emission windows with Ag2X (X = S, Se) QDs using easy-to-prepare thio/selenourea precursors and their analogues. The aqueous phase transfer of these QDs with a high conservation of fluorescence quantum yield (retention up to ∼90%) and colloidal stability is demonstrated. A bimodal NIR-II/MRI contrast agent with a tunable fluorescence and high T1 relaxivity of 408 mM-1 s-1 per QD (size ∼ 2.2 nm) and 990 mM-1 s-1 per QD (size ∼ 4.2 nm) has been prepared by grafting 50 and 120 monoaqua Gd(iii) complexes respectively to two differently sized Ag2S QDs. The size of the nanocrystals is crucial for tuning the Gd payload and the relaxivity.

When rare earth meets carbon nanodots: mechanisms, applications and outlook

Rare earth (RE) elements are widely used in the luminescence and magnetic fields by virtue of their abundant 4f electron configurations. However, the overall performance and aqueous stability of single-component RE materials need to be urgently improved to satisfy the requirements for multifunctional applications. Carbon nanodots (CNDs) are excellent nanocarriers with abundant functional surface groups, excellent hydrophilicity, unique photoluminescence (PL) and tunable features. Accordingly, RE-CND hybrids combine the merits of both RE and CNDs, which dramatically enhance their overall properties such as luminescent and magnetic-optical imaging performances, leading to highly promising practical applications in the future. Nevertheless, a comprehensive review focusing on the introduction and in-depth understanding of RE-CND hybrid materials has not been reported to date. This review endeavors to summarize the recent advances of RE-CNDs, including their interaction mechanisms, general synthetic strategies and applications in fluorescence, biosensing and multi-modal biomedical imaging. Finally, we present the current challenges and the possible application perspectives of newly developed RE-CND materials. We hope this review will inspire new design ideas and valuable references in this promising field in the future.

The Renal Clearable Magnetic Resonance Imaging Contrast Agents: State of the Art and Recent Advances

The advancements of magnetic resonance imaging contrast agents (MRCAs) are continuously driven by the critical needs for early detection and diagnosis of diseases, especially for cancer, because MRCAs improve diagnostic accuracy significantly. Although hydrophilic gadolinium (III) (Gd3+) complex-based MRCAs have achieved great success in clinical practice, the Gd3+-complexes have several inherent drawbacks including Gd3+ leakage and short blood circulation time, resulting in the potential long-term toxicity and narrow imaging time window, respectively. Nanotechnology offers the possibility for the development of nontoxic MRCAs with an enhanced sensitivity and advanced functionalities, such as magnetic resonance imaging (MRI)-guided synergistic therapy. Herein, we provide an overview of recent successes in the development of renal clearable MRCAs, especially nanodots (NDs, also known as ultrasmall nanoparticles (NPs)) by unique advantages such as high relaxivity, long blood circulation time, good biosafety, and multiple functionalities. It is hoped that this review can provide relatively comprehensive information on the construction of novel MRCAs with promising clinical translation.

Recent Developments of Carbon Dots in Biosensing: A Review

Early diagnosis of diseases is of great importance because it increases the chance of a cure and significantly reduces treatment costs. Thus, development of rapid, sensitive, and reliable biosensing techniques is essential for the benefits of human life and health. As such, various nanomaterials have been explored to improve performance of biosensors, among which, carbon dots (CDs) have received enormous attention due to their excellent performance. In this Review, the recent advancements of CD-based biosensors have been carefully summarized. First, biosensors are classified according to their sensing strategies, and the role of CDs in these sensors is elaborated in detail. Next, several typical CD-based biosensors (including CD-only, enzymatic, antigen-antibody, and nucleic acid biosensors) and their applications are fully discussed. Last, advantages, challenges, and perspectives on the future trends of CD-based biosensors are highlighted.

Safe and efficient magnetic resonance imaging of acute myocardial infarction with gadolinium-doped carbon dots

Aim: The magneto-fluorescent gadolinium-doped carbon dots (Gd-CDs) were developed as a cardiac MR imaging contrast agent to detect the infarcted myocardium on a myocardial ischemia/reperfusion (I/R) mice model. Materials & methods: The chemophysical features, cardiac MR imaging effect, biodistribution and biocompatibility of Gd-CDs were studied. Results: The ultrasmall size and good aqueous dispersibility endows Gd-CDs with high longitudinal relaxivity, intense fluorescence, excellent physiological stability and superior biocompatibility. More importantly, Gd-CDs preferentially target the infarcts as determined by the confocal microscopy and MR imaging on the I/R mice at the acute stage of myocardial infarction. Conclusion: Gd-CDs manifest great potential for development as an MR imaging contrast agent to facilitate accurate visualization and image-guided therapy of acute myocardial infarction.

Affibody-Modified Gd@C-Dots with Efficient Renal Clearance for Enhanced MRI of EGFR Expression in Non-Small-Cell Lung Cancer

Purpose

Gd-encapsulated carbonaceous dots (Gd@C-dots) have excellent stability and magnetic properties without free Gd leakage, therefore they can be considered as a safe alternative T1 contrast agent to commonly used Gd complexes. To improve their potential for cancer diagnosis and treatment, affibody-modified Gd@C-dots targeting non-small-cell lung cancer (NSCLC) EGFR-positive tumors with enhanced renal clearance were developed and synthesized.

Materials and Methods

Gd@C-dots were developed and modified with Ac-Cys-Z_EGFR:1907 through EDC/NHS. The size, morphology, and optical properties of the Gd@C-dots and Gd@C-dots-Cys-Z_EGFR:1907 were characterized. Targeting ability was evaluated by in vitro and in vivo experiments, respectively. Residual gadolinium concentration in major organs was detected with confocal imaging and inductively coupled plasma mass spectrometry (ICP-MS) ex vivo. H&E staining was used to assess the morphology of these organs.

Results

Gd@C-dots with nearly 20 nm in diameter were developed and modified with Ac-Cys-Z_EGFR:1907. EGFR expression in HCC827 cells was higher than NCI-H520. In cell uptake assays, EGFR-expressing HCC827 cells exhibited significant MR T1WI signal enhancement when compared to NCI-H520 cells. Cellular uptake of Gd@C-dots-Cys-Z_EGFR:1907 was reduced, when Ac-Cys-Z_EGFR:1907 was added. In vivo targeting experiments showed that the probe signal was significantly higher in HCC827 than NCI-H520 xenografts at 1 h after injection. In contrast to Gd@C-dots, Gd@C-dots-Cys-Z_EGFR:1907 nanoparticles can be efficiently excreted through renal clearance. No morphological changes were observed by H&E staining in the major organs after injection of Gd@C-dots-Cys-Z_EGFR:1907.

Conclusion

Gd@C-dots-Cys-Z_EGFR:1907 is a high-affinity EGFR-targeting probe with efficient renal clearance and is therefore a promising contrast agent for clinical applications such as diagnosis and treatment of NSCLC EGFR-positive malignant tumors.

Photonic Carbon Dots as an Emerging Nanoagent for Biomedical and Healthcare Applications

As a class of carbon-based nanomaterials, carbon dots (CDs) have attracted enormous attention because of their tunable optical and physicochemical properties, such as absorptivity and photoluminescence from ultraviolet to near-infrared, high photostability, biocompatibility, and aqueous dispersity. These characteristics make CDs a promising alternative photonic nanoagent to conventional fluorophores in disease diagnosis, treatment, and healthcare managements. This review describes the fundamental photophysical properties of CDs and highlights their recent applications to bioimaging, photomedicine (e.g., photodynamic/photothermal therapies), biosensors, and healthcare devices. We discuss current challenges and future prospects of photonic CDs to give an insight into developing vibrant fields of CD-based biomedicine and healthcare.

Renal clearable nanocarriers: Overcoming the physiological barriers for precise drug delivery and clearance

Physiological barriers encountered in the clinical translation of cancer nanomedicines inspire the community to more deeply understand nano-bio interactions in not only tumor microenvironment but also entire body and develop new nanocarriers to tackle these barriers. Renal clearable nanocarriers are one kind of these newly emerged drug delivery systems (DDSs), which enable drugs to rapidly penetrate into the tumor cores with no need of long blood retention and escape macrophage uptake in the meantime they can also enhance body elimination of non-targeted anticancer drugs. As a result, they can improve therapeutic efficacies and reduce side effects of anticancer drugs. Not limited to anticancer drugs, diagnostic agents can also be achieved with these renal clearable DDSs, which might also be applied to improve the precision in the gene editing and immunotherapy in the future.

Gadolinium-Rose Bengal Coordination Polymer Nanodots for MR-/Fluorescence-Image-Guided Radiation and Photodynamic Therapy

Combination therapy based on nanomedicine has gained momentum in oncology in recent years, offering superior safety and efficacy over monotherapies. It is critical to design theranostics that are composed of imaging and therapeutic agents already approved. Herein, gadolinium (Gd)-rose bengal coordination polymer nanodots (GRDs) are reported. The GRDs exhibit a unique absorption property and 7.7-fold luminescence enhancement, as well as a 1.9-fold increase in singlet oxygen generation efficiency over free rose bengal. Meanwhile, GRDs exhibit a twofold increase in r₁ relaxivity over gadopentetic acid (Gd-DTPA) and have better X-ray absorption ability than rose bengal alone. These excellent properties of the GRDs are verified both in vitro and in vivo. The combination of photodynamic therapy (PDT) and radiation therapy (RT) more significantly inhibits tumor growth than monotherapies (i.e., PDT or RT). This work offers a new route to designing and synthesizing Gd-based nanotheranostics for image-guided cancer therapy.