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

Application of nano-radiosensitizers in non-small cell lung cancer

Radiotherapy stands as a cornerstone in the treatment of numerous malignant tumors, including non-small cell lung cancer. However, the critical challenge of amplifying the tumoricidal effectiveness of radiotherapy while minimizing collateral damage to healthy tissues remains an area of significant research interest. Radiosensitizers, by methods such as amplifying DNA damage and fostering the creation of free radicals, play a pivotal role in enhancing the destructive impact of radiotherapy on tumors. Over recent decades, nano-dimensional radiosensitizers have emerged as a notable advancement. Their mechanisms include cell cycle arrest in the G2/M phase, combating tumor hypoxia, and others, thereby enhancing the efficacy of radiotherapy. This review delves into the evolving landscape of nanomaterials used for radiosensitization in non-small cell lung cancer. It provides insights into the current research progress and critically examines the challenges and future prospects within this burgeoning field.

A potent multifunctional ZIF-8 nanoplatform developed for colorectal cancer therapy by triple-delivery of chemo/radio/targeted therapy agents

BACKGROUND

Multimodal cancer therapy has garnered significant interest due to its ability to target tumor cells from various perspectives. The advancement of novel nano-delivery platforms represents a promising approach for improving treatment effectiveness while minimizing detrimental effects on healthy tissues.

METHODS

This study aimed to develop a multifunctional nano-delivery system capable of simultaneously delivering an anti-cancer drug, a radiosensitizer agent, and a targeting moiety (three-in-one) for the triple combination therapy of colorectal cancer (CRC). This unique nano-platform, called Apt-PEG-DOX/ZIF-8@GQD, encapsulated both doxorubicin (DOX) and graphene quantum dots (GQDs) within the zeolitic imidazolate framework-8 (ZIF-8). To enhance the safety and anti-cancer potential of the platform, heterobifunctional polyethylene glycol (PEG) and an epithelial cell adhesion molecule (EpCAM) aptamer were conjugated with the system, resulting in the formation of targeted Apt-PEG-DOX/ZIF-8@GQD NPs. The physical and chemical characteristics of Apt-PEG-DOX/ZIF-8@GQD were thoroughly examined, and its therapeutic efficacy was evaluated in combination with radiotherapy (RT) against both EpCAM-positive HT-29 and EpCAM-negative CHO cells. Furthermore, the potential of Apt-PEG-DOX/ZIF-8@GQD as a tumor-specific, radio-enhancing, non-toxic, and controllable delivery system for in vivo cancer treatment was explored using immunocompromised C57BL/6 mice bearing human HT-29 tumors.

RESULTS

The large surface area of ZIF-8 (1013 m2 g-1) enabled successful loading of DOX with an encapsulation efficiency of approximately ∼90%. The synthesis of Apt-PEG-DOX/ZIF-8@GQD resulted in uniform particles with an average diameter of 100 nm. This targeted platform exhibited rapid decomposition under acidic conditions, facilitating an on-demand release of DOX after endosomal escape. In vitro experiments revealed that the biocompatible nano-platform induced selective toxicity in HT-29 cells by enhancing X-ray absorption. Moreover, in vivo experiments demonstrated that the therapeutic efficacy of Apt-PEG-ZIF-8/DOX@GQD against HT-29 tumors was enhanced through the synergistic effects of chemotherapy, radiotherapy, and targeted therapy, with minimal side effects.

CONCLUSION

The combination of Apt-PEG-DOX/ZIF-8@GQD with RT as a multimodal therapy approach demonstrated promising potential for the targeted treatment of CRC and enhancing therapeutic effectiveness. The co-delivery of DOX and GQD using this nano-platform holds great promise for improving the outcome of CRC treatment.

Zero-Dimensional Carbon Nanomaterials for Fluorescent Sensing and Imaging

Advances in nanotechnology and nanomaterials have attracted considerable interest and play key roles in scientific innovations in diverse fields. In particular, increased attention has been focused on carbon-based nanomaterials exhibiting diverse extended structures and unique properties. Among these materials, zero-dimensional structures, including fullerenes, carbon nano-onions, carbon nanodiamonds, and carbon dots, possess excellent bioaffinities and superior fluorescence properties that make these structures suitable for application to environmental and biological sensing, imaging, and therapeutics. This review provides a systematic overview of the classification and structural properties, design principles and preparation methods, and optical properties and sensing applications of zero-dimensional carbon nanomaterials. Recent interesting breakthroughs in the sensitive and selective sensing and imaging of heavy metal pollutants, hazardous substances, and bioactive molecules as well as applications in information encryption, super-resolution and photoacoustic imaging, and phototherapy and nanomedicine delivery are the main focus of this review. Finally, future challenges and prospects of these materials are highlighted and envisaged. This review presents a comprehensive basis and directions for designing, developing, and applying fascinating fluorescent sensors fabricated based on zero-dimensional carbon nanomaterials for specific requirements in numerous research fields.

Carbon Dots in Treatment of Pediatric Brain Tumors: Past, Present, and Future Directions

Pediatric brain tumors remain a significant source of morbidity and mortality. Though developments have been made in treating these malignancies, the blood-brain barrier, intra- and inter-tumoral heterogeneity, and therapeutic toxicity pose challenges to improving outcomes. Varying types of nanoparticles, including metallic, organic, and micellar molecules of varying structures and compositions, have been investigated as a potential therapy to circumvent some of these inherent challenges. Carbon dots (CDs) have recently gained popularity as a novel nanoparticle with theranostic properties. This carbon-based modality is highly modifiable, allowing for conjugation to drugs, as well as tumor-specific ligands in an effort to more effectively target cancerous cells and reduce peripheral toxicity. CDs are being studied pre-clinically. The ClinicalTrials.gov site was queried using the search terms: brain tumor and nanoparticle, liposome, micelle, dendrimer, quantum dot, or carbon dot. At the time of this review, 36 studies were found, 6 of which included pediatric patients. Two of the six studies investigated nanoparticle drug formulations, whereas the other four studies were on varying liposomal nanoparticle formulations for the treatment of pediatric brain tumors. Here, we reviewed the context of CDs within the broader realm of nanoparticles, their development, promising pre-clinical potential, and proposed future translational utility.

Luminescent Carbon Nanodots Doped with Gadolinium (III): Purification Criteria, Chemical and Biological Characterization of a New Dual Fluorescence/MR Imaging Agent

Carbon Dots (CDs) are luminescent quasi-spherical nanoparticles, possessing water solubility, high biocompatibility, and tunable chemical and physical properties for a wide range of applications, including nanomedicine and theranostics. The evaluation of new purification criteria, useful to achieve more reliable CDs, free from the interference of artifacts, is currently an object of debate in the field. Here, new CDs doped with gadolinium (Gd (III)), named Gd@CNDs, are presented as multifunctional probes for Magnetic Resonance Imaging (MRI). This new system is a case of study, to evaluate and/or combine different purification strategies, as a crucial approach to generate CDs with a better performance. Indeed, these new amorphous Gd@CNDs display good homogeneity, and they are free from emissive side products. Gd@CNDs (7-10 nm) contain 7% of Gd (III) w/w, display suitable and stable longitudinal relaxivity (r₁ ) and with emissive behavior, therefore potentially useful for both MR and fluorescence imaging. They show good biocompatibility in both cellular and in vivo studies, cell permeability, and the ability to generate contrast in cellular pellets. Finally, MRI recording T₁ -weighted images on mice after intravenous injection of Gd@CNDs, show signal enhancement in the liver, spleen, and kidney 30 min postinjection.

Size-changeable nanoprobes for the combined radiotherapy and photodynamic therapy of tumor

PURPOSE

Radiation therapy (RT) and photodynamic therapy (PDT) are promising while challenging in treating tumors. The potential radiation resistance of tumor cells and side effects to healthy tissues restrict their clinical treatment efficacy. Effective delivery of therapeutic agents to the deep tumor tissues would be available for tumor-accurate therapy and promising for the tumor therapy. Thus, developing nanoprobes with effectively delivering radiotherapy sensitizers and photosensitizers to the interior of tumors is needed for the accurate combined RT and PDT of tumor.

METHODS

The size-changeable nanoprobes of Gd₂O₃@BSA-BSA-Ce6 (BGBC) were synthesized with a crosslinking method. Magnetic resonance imaging (MRI) and in vivo near-infrared (NIR) imaging were measured to evaluate the nanoprobes' tumor accumulation and intratumor penetration effect. The tumor suppression effect of combined RT and PDT with these nanoprobes was also studied for the 4T1 bearing Balb/c mice.

RESULTS

The nanoprobes BGBC showed high tumor accumulation and disintegrated into small particles responding to the photo-irradiation-produced reactive oxygen species (ROS), allowing for tumor penetration. Abundant radiotherapy sensitizers and photosensitizers were delivered to the deep tumor tissues, which is available for the accurate therapy of tumor. In addition, the BGBC displayed outstanding MRI and fluorescence imaging effects for evaluating the biodistribution and tumor suppression effect of nanoprobes. Consequently, significant tumor suppression effect was obtained based on the accurate tumor treatment with the combined RT and PDT.

CONCLUSION

The designed size-changeable nanoprobes BGBC showed excellent tumor accumulation and deep tumor penetration, resulting in a significant tumor suppression effect based on the combined RT and PDT. This study provides a novel strategy for dual delivery of radiotherapy sensitizers and photosensitizers into the deep tumor tissues and is promising for the accurate theranostics of tumor.

Magnetic and near-infrared-II fluorescence Au-Gd nanoclusters for imaging-guided sensitization of tumor radiotherapy

The significant role of multifunctional nanoprobes with complementary advantages in magnetic and near-infrared-II (NIR-II, 1000-1700 nm) fluorescence properties has been documented in precision cancer theranostics. However, certain limitations, including the large size (>10 nm), low NIR-II fluorescence quantum yield (QY < 1.0%), and inefficient magnetic performance (relaxation rate < 5.0 s^-1 mM^-1) of nanoprobes, restrict their biomedical applications and clinical translation. Albumin-based biomineralization was adopted to prepare bright NIR-II Au NCs, which were further conjugated with DTPA and Gd ions to produce magnetic and NIR-II Au-Gd NCs. Albumin-based biomineralization helped to develop ultrasmall Au-Gd nanoclusters with ultrasmall size (∼2 nm), high NIR-II fluorescence QY (∼3.0%), and effective magnetic resonance imaging (MRI) performance (relaxation rate (r1) = 22.6 s^-1 mM^-1). On the one hand, Au-Gd NCs achieved NIR-II fluorescence and MRI dual-modal imaging of tumors with a high signal-to-background ratio (SBR = 8.2) in mice. On the other hand, their effective metabolism simultaneously through the kidney and liver minimized their toxicity in vivo. Moreover, compared to the control group, the survival time of tumor-bearing mice was extended by three times when Au-Gd NCs with high-Z elements were used to perform dual-modal imaging-guided sensitization of tumor radiotherapy. Thus, ultrasmall nanoprobes with complementary imaging modalities and therapeutic functions manifest great potential in cancer precision diagnosis and therapy.

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.