Carbon nanotubes utilization has gained significant attention for being a prospective approach for exploring a variety of biomedical applications, particularly in cancer therapy. These CNTs exhibit exceptional properties, including the ability to be modified for the purpose of targeted drug delivery by functionalizing them along with biocompatible molecules [59-61]. Furthermore, due to their unique electrical and optical properties, which enable their application in diagnostic imaging techniques such as near-infrared fluorescence and Raman spectroscopy, CNTs have demonstrated significant potential in cancer therapy [62,63]. However, while initial findings are promising, further in-depth studies are required to fully elucidate their therapeutic capabilities and to rigorously assess them in clinical settings for patient benefit in terms of efficacy and safety.
In scientific research, bibliometric analysis is essential since it permits a thorough examination and visual representation concerning enormous knowledge repositories [13]. The current research attempts to fill in the gaps that currently exist for our understanding through the provision of a quantitative assessment of global research on CNTs, with a focus on cancer therapy research. For attaining this goal, we gathered pertinent scientific literature sourced via the prestigious Scopus database, renowned for being the most comprehensive repository of peer-reviewed articles that encompasses abstracts along with citations. Accompanied by means of vast searching capabilities and analytical tools, Scopus assists with data extraction to support additional visualization as well as investigation. Scopus-indexed journals undergo rigorous evaluations and meticulous peer-review processes, strengthening their trustworthiness.
In addition, Scopus sorts these scientific journals by subject matter, thereby providing a thorough resource for those investigating CNTs application in cancer treatment research. Findings derived from the study we performed furnish crucial perspectives for guiding researchers and institutions in prioritization their attempts and directing forthcoming investigations into this burgeoning sector. The present study performed an intensive search to compile all the relevant literature from the last two decades that concerned the utilization of CNTs in cancer therapy. Solely reviews and papers written in English and subjected to a thorough peer review process were incorporated in this study.
Our findings indicated a notable increase in publications within this particular arena during the past five years, with almost 30% of the articles being released between the years 2020 and 2024, as shown in Figure 1. This growth reflects increasing global interest in nanotechnology-based cancer therapies and highlights the expanding role of CNTs in advanced biomedical applications. From 445 journals indexed in Scopus, a total of 1,221 papers were retrieved. Table 2 highlights that the most prolific top ten journals accounted for approximately 17% out of all published articles. The obtained documents produced 72,181 citations in total, having an average of 59.1 citations for each document. Moreover, the published publications had an h-index of 124, demonstrating a considerable degree of reader interest. The most citations have been received by the ACS Nano journal. As demonstrated in Table 2, the documents that were commonly referenced were disseminated between the years 2004 and 2009.
However, recently published publications failed to garner adequate citations to contend with the documents mentioned previously. Recent publications tend to have lower citation counts due to the limited time since publication, which restricts the accumulation of citations. Of all the documents that were retrieved, the scholarly publication by Poland C. et al., published in Nature Nanotechnology [64], garnered the greatest citation count. The essay examines that exposing the mesothelial lining of the body cavity of mice, as a surrogate for the mesothelial lining of the chest cavity, to long multiwalled carbon nanotubes results in asbestos-like, length-dependent, pathogenic behavior.
In accordance with the geographic distribution examination of the acquired papers, academics from China authored the highest count of publications, totaling 333 documents (27%). Consequently, researchers from USA released 283 documents, constituting 23% of the total.
The investigation of the scientific influence concerning these countries, as measured by the average number of citations per document, depicts that documents originating from United States showcase the highest total scientific impact, with 120.7 citations per document. Afterwards, with 96 citations per document, the United Kingdom is ranked second, and France occupies the third rank having 86.6 citations per document, as demonstrated in Table 3 and Figure 2.
Within the scope of this investigation, the acquired documents amassed 72,181 citations in total. The significant nature of this topic is underscored through the substantial number of citations, and further reinforced by articles in esteemed academic journals. This finding has been evidenced by the data displayed in Table 1, thereby implies that all of the leading 10 journals are listed into Q1 category. The investigation also evaluated international collaborations amongst countries associated with this scientific domain. The most prominent partnership was established between USA and China, as revealed by the network visualization of international research partnerships, depicted in Figure 2.
Research Hotspots and Trends
Through analyzing the co-occurrences of author keywords found within the gathered literature, which surpassed 15 incidences, Biblioshiny and VOSview were both employed to map hotspots. In consequence, five overlapping conceptual clusters comprising 24 primary keywords were discovered. These clusters emphasize the fields of focus along with study emphasis of the retrieved materials.
The five mentioned previous clusters, determined using VOSviewer and Biblioshiny, were utilized to infer the subsequently occurring hotspots, as shown in Figure 3C and Figure 4.
Cluster 1: Harnessing CNTs for Cancer Therapy (single-walled CNTs, breast cancer, cytotoxicity, photothermal therapy, cancer therapy, apoptosis, and cisplatin): Single-walled carbon nanotubes (SWCNTs) have gained significant attention in cancer therapy due to their unique physicochemical properties, including high surface area, biocompatibility, and the ability to easily functionalize for targeted drug delivery [65]. These nanotubes can serve as carriers for various therapeutic agents, including chemotherapy drugs, RNA molecules, and proteins, allowing for more precise targeting of cancer cells while minimizing damage to healthy tissues [66]. Additionally, SWCNTs have shown promise in photothermal therapy; where they can convert near-infrared light into heat to selectively destroy cancer cells [67]. CNTs offer a versatile platform in the treatment of breast cancer, particularly for enhancing the delivery and efficacy of chemotherapy. Their unique structure allows them to encapsulate hydrophobic drugs, improving solubility and stability in the bloodstream [18]. Moreover, CNTs can be conjugated with specific targeting agents, such as monoclonal antibodies, to improve selective accumulation at the tumor site. This targeted approach not only enhances the therapeutic effect but it additionally diminishes the side effects associated that are related to traditional chemotherapy [30]. CNTs can also be utilized for monitoring treatment response through imaging techniques, as they are capable of providing contrast in modalities like MRI [68].
On the other hand, CNTs have raised concerns regarding their cytotoxicity, which gets influenced by factors such as their surface charge, size, and functionalization. Studies have shown that CNTs can induce oxidative stress, inflammation, and cellular damage, leading to cytotoxic effects in various cell types [19]. However, the degree of toxicity varies significantly based on the physicochemical properties of the CNTs, with functionalization often mitigating harmful effects [69]. For example, surface modification with biocompatible molecules, such as polyethylene glycol (PEG), can reduce the inflammatory response and enhance their biocompatibility [70,71]. Additionally, CNTs’ ability to penetrate cell membranes and interact with intracellular components has sparked interest in their potential use for drug delivery systems, although this also necessitates a careful evaluation of their long-term safety profile. As the body of research on CNTs’ cytotoxicity grows, it is clear that balancing their therapeutic benefits with their potential toxic effects is crucial for their successful clinical application [72,73].
CNTs offer a promising approach in photothermal therapy (PTT) due to their ability to efficiently absorb and convert near-infrared light into heat. This makes them effective in targeted cancer treatment, where CNTs can be directed to tumor sites and activated by NIR light to induce localized thermal damage to cancer cells. Their unique structural properties, such as high surface area and conductivity, enable them to generate significant heat upon light exposure, making them ideal for enhancing the efficacy of PTT [74]. Functionalization with targeting agents, such as antibodies or peptides, allows for precise delivery to cancer cells, minimizing damage to healthy tissues. Despite their potential, careful consideration of heat management and biocompatibility is crucial to ensure that CNTs can be safely integrated into clinical practices for cancer treatment [75].
Carbon nanotubes (CNTs) have been shown to play a role in the induction of apoptosis, particularly in cancer cells, due to their ability to interact with cellular components and trigger cell death pathways. CNTs can facilitate the delivery of pro-apoptotic agents or induce oxidative stress, leading to mitochondrial dysfunction and the activation of apoptotic signaling. Their unique properties, including high surface area and ability to be functionalized with various biomolecules, enable precise targeting of tumor cells, where they can promote apoptosis without affecting healthy tissues [76,77]. Additionally, CNTs have been used in combination with chemotherapy agents to enhance their apoptotic effects, sensitizing cancer cells to treatment. However, the exact mechanisms by which CNTs influence apoptosis are still being studied, and concerns regarding their potential to induce unwanted toxicity or inflammation in normal cells must be addressed before their widespread clinical use [78,79].
Cisplatin, a potent chemotherapy agent, has been widely used in the treatment of various cancers; however, its clinical effectiveness is often limited by issues such as poor solubility, systemic toxicity, and the development of drug resistance [80-82]. Carbon nanotubes (CNTs) offer a promising solution to these challenges by serving as carriers for cisplatin, enhancing its solubility and targeted delivery to tumor sites. When functionalized with cisplatin, CNTs facilitate the controlled release of the drug, ensuring a higher concentration at the tumor while minimizing exposure to healthy tissues. Moreover, CNTs can enhance the uptake of cisplatin into cancer cells, overcoming resistance mechanisms and increasing its cytotoxic effects [83,84]. Despite the therapeutic potential, the safety profile of CNT-based cisplatin delivery systems needs further investigation to address concerns related to toxicity, biodegradability, and long-term biocompatibility [85]
Cluster 2: MWCNTs in Drug Delivery and Biosensing (multi-walled carbon nanotubes, doxorubicin, biosensor, chitosan, electrochemical sensor and gold nanoparticles): The unique properties of multi-walled carbon nanotubes (MWCNTs), including their high surface area, mechanical strength, and ease of functionalization, have positioned them as a promising tool in nanomedicine [86,87]. In cancer therapy, MWCNTs are increasingly employed as carriers for the delivery of chemotherapeutic agents, such as doxorubicin, a potent anti-cancer drug. By attaching doxorubicin to the surface of MWCNTs, researchers have been able to boost the solubility, stability, and targeted delivery of the drug, which enhances its therapeutic efficacy while minimizing systemic side effects [88-90]. Furthermore, MWCNTs’ ability to penetrate cell membranes allows for efficient intracellular delivery, making them particularly valuable in overcoming drug resistance mechanisms observed in many cancer types. To enhance their biocompatibility and prevent premature drug release, MWCNTs are often combined with biopolymers like chitosan, which not only stabilizes the drug-nanotube complex but also improves the uptake and distribution of the drug within tumor cells. This combination ensures that doxorubicin remains active in its therapeutic role without causing excessive toxicity to healthy tissues [91,92]. Beyond their application in drug delivery, MWCNTs have also been explored in the development of highly sensitive biosensors [93-95]. When integrated with gold nanoparticles, MWCNTs create hybrid nanocomposites with exceptional electrical conductivity and surface area, making them ideal candidates for electrochemical biosensing. These sensors have shown remarkable sensitivity in detecting cancer biomarkers, enabling early diagnosis and real-time monitoring of treatment progress [96,97]. The synergy between MWCNTs, gold nanoparticles, and chitosan further enhances the performance of electrochemical sensors, leading to increased specificity and detection limits, which are critical in the early detection of cancer and other diseases [98]. The combination of these technologies for both therapeutic and diagnostic purposes holds significant promise for advancing personalized medicine and improving patient outcomes.
Cluster 3: Exploring CNT functionalization and cancer treatment (Carbon Nanotubes, Cancer, Functionalization, Toxicity, Folic Acid): Recent advancements in nanomedicine have positioned carbon nanotubes (CNTs) as highly promising candidates for cancer therapy, offering precise drug delivery and enhanced therapeutic efficiency [99]. However, their biomedical applications are often hindered by concerns related to cytotoxicity and potential long-term accumulation in tissues. To address these challenges, extensive research has focused on functionalization techniques that modify the surface of CNTs, improving their solubility, reducing toxicity, and increasing their specificity for cancer cells [100]. One of the most effective approaches involves conjugating CNTs with folic acid, leveraging the overexpression of folate receptors on many cancer cells to enable selective targeting. This functionalization strategy enhances the cellular uptake of CNT-based therapeutics, ensuring higher drug concentrations at tumor sites while minimizing adverse effects on healthy tissues [101-103]. Additionally, folic acid-functionalized CNTs serve as efficient carriers for chemotherapeutic agents, allowing for controlled drug release and prolonged retention within malignant cells. Functionalization not only optimizes therapeutic outcomes but also mitigates oxidative stress and inflammatory responses often associated with unmodified CNTs, making them more suitable for clinical applications [104]. Beyond drug delivery, folic acid-modified CNTs have demonstrated potential in cancer diagnostics, where they can improve imaging contrast and biomarker detection [105-107]. Despite these promising developments, further research is essential to fine-tune functionalization methods, ensuring that CNT-based platforms achieve maximum efficacy with minimal toxicity. Long-term in vivo studies will be critical to evaluating their pharmacokinetics, clearance mechanisms, and overall safety before transitioning to widespread clinical use [47,108]. As functionalization strategies continue to evolve, CNTs hold immense potential for revolutionizing cancer treatment by providing highly efficient, targeted, and minimally invasive therapeutic solutions [109,110].
Cluster 4: Advancing Drug Delivery with CNTs (Targeted Drug Delivery, Controlled Release, Adsorption): The effectiveness of cancer therapy depends not only on the potency of the drug but also on its ability to reach the tumor site in a controlled and sustained manner. Carbon nanotubes (CNTs) have emerged as highly efficient nanocarriers due to their ability to adsorb therapeutic molecules and release them in a targeted fashion [101,111]. Their large surface area allows for strong interactions with a wide range of drugs through physical adsorption and chemical attachment, ensuring high drug-loading capacity [112,113]. Functionalized CNTs can be engineered to respond to specific biological stimuli, such as pH changes in the tumor microenvironment, to trigger controlled drug release precisely where it is needed. This approach prevents premature drug degradation, reduces systemic toxicity, and enhances therapeutic efficiency [3,27,114]. Additionally, the adsorption properties of CNTs enable them to carry multiple therapeutic agents simultaneously, opening possibilities for combination therapies that attack cancer through different mechanisms [14]. While promising, further research is required to optimize CNT-based drug carriers for improved stability, reduced unintended interactions with healthy cells, and enhanced biodegradability to facilitate their safe transition into clinical applications [43,115].
Cluster 5: CNTs in nanomedicine for lung cancer (nanomedicine, nanotechnology, lung cancer): Nanomedicine, empowered by advancements in nanotechnology, holds immense potential for revolutionizing lung cancer treatment. Carbon nanotubes (CNTs), as key components of nanomedicine, offer a highly versatile platform for targeted drug delivery, enhancing the precision and efficacy of cancer therapies [19,67,104]. In the context of lung cancer, CNTs can be functionalized with specific ligands to target tumor cells selectively, overcoming challenges related to conventional chemotherapy, such as low drug bioavailability and non-specific toxicity. Moreover, their unique structural properties allow CNTs to interact with and penetrate cancerous tissues, delivering therapeutic agents directly to the site of the tumor [74,93,116]. Nanotechnology-driven innovations, such as the use of CNTs for controlled drug release and real-time monitoring, have significantly improved the potential for personalized cancer therapies [1,117,118]. As research progresses, CNT-based nanomedicines are being designed to tackle the complexities of lung cancer, with promising results in preclinical models showing enhanced treatment outcomes [119]. However, the successful translation of CNT-based therapies into clinical settings requires further studies to assess long-term safety, biocompatibility, and the potential for overcoming drug resistance in lung cancer cells.
Study limitations
Considering our study purely utilized Scopus database for document retrieval, it is of the utmost importance to recognize that relevant research on CNTs and cancer may be released by journals that are not indexed by Scopus. Furthermore, only restricted assortment of 2024 publications may not have been incorporated into Scopus during our investigation, presumably leading to their omission from the investigation we conduct. Furthermore, we excluded items which remained in “in press” phase. Therefore, it is plausible that these circumstances have resulted in the neglect of particularly relevant research articles or review papers on the subject that were published into the late 2024. The fact that we merely utilized papers produced in English is a further limitation of our investigation. Scholars may gain significant insights about the application CNTs in cancer therapy from research accomplished in other languages. At long last, it is essential to remark that the findings of the study could be impacted by even slight discrepancies in the affiliations or names of the authors.
Conclusions
Encompassing a wide range of scientific fields, our extensive bibliometric study reveals the immense prospects of application of CNTs in cancer therapy. The revolutionary significance of CNTs is highlighted by our investigation of the present status of the field and potential avenues for future research. Significant attention has been directed towards the potential integration of CNTs in cancer diagnostics and treatment, as they hold the promise for improving patient outcomes along with fewer adverse effects. Moreover, CNTs utilization in cancer therapy aligns with the growing focus on sustainable nanotechnology, offering a promising and responsible method for developing targeted treatments with enhanced therapeutic efficacy.
Our bibliometric analysis, in essence, accentuates the significance of ongoing research, cooperation align with the translation to clinical applications in addition to highlighting the recent advancements in the use of CNTs in cancer therapy.
