A team of researchers at the Center for Nanoparticle Research within the Institute for Basic Science (IBS; Seoul, Korea) has developed a multifunctional endoscope that integrates transparent bioelectronics such as lasers with theranostic nanoparticles. The work could enable testing new medications and tailoring a unique treatment plan for a cancer patient.
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Conventional endoscopes lack the spatial resolution necessary to detect and treat small cancers and other abnormalities. They are equipped with a flexible tube fitted with a camera, lens, and light delivery system, providing both maneuverability and direct visualization of the gastrointestinal tract. However, despite the proven utility of current surgical endoscopes, onboard sensors coupled with treatments are unavailable because of the macro-scale size of the conventional system, preventing diagnosis and therapy of micro-scale tumors.
Recognizing this, the research team--led by Professor Taeghwan Hyeon, the director of the Centre for Nanoparticle Research--demonstrated a multifunctional surgical endoscope system to diagnose and treat intestinal diseases such as colon cancers. Their smart endoscope system contains transparent bioelectronics, which provides pH-based sensing combined with radio-frequency ablation (RFA), a medical procedure in which part of the electrical conduction of a tumor is ablated using heat generated from a medium-frequency alternating current.
|Schematic illustrations of the design strategy and mode of use for the multifunctional endoscope system based on transparent bioelectronic devices and theranostic nanoparticles.|
The system’s additional sensors for monitoring mechanical contacts and mapping temperatures provide accurate physiological sensing capabilities during cancer detection and ablation. The transparency enables optimal integration of a number of multifunctional sensing and therapeutic components on the endoscope tip without blocking the line of sight of the camera or light. By loading transparent bioelectronics on the camera of the endoscope, the tissue observed through the camera in fluorescence mapping and phototherapies can be exactly matched with the characterized ablated tissues by transparent devices. The system also has custom-designed, biocompatible NPs with phototherapeutic and chemotherapeutic agents, which can be delivered locally and activated with light. According to the team’s paper, this multifunctional endoscopic system could be useful for the detection of flat or depressed abnormal growths. Synergistic effects between the transparent bioelectronics and theranostic nanoparticles can enhance the accuracy of tumor detection and provide treatment.
Controlled laboratory experiments within living organisms, known as in vivo experiments, were performed on mice. The results highlighted the utility of this technology for its accurate detection, delineation, and rapid targeted therapy of colon cancer or precancerous lesions. An intravenous injection of nanoparticles was administered to actively target colon cancer cells. Imaging of fluorescence dyes loaded on these nanoparticles provided optical information about the spatial distribution of cancer cells. The endoscope allowed laser light to access suspicious sites exposed to nanoparticles. These regions were easily observed because of the transparency of the integrated transparent bioelectronics on the endoscope camera. The transparent bioelectronics and associated sensors provided additional electrochemical analysis of the tumor distribution. After a suspicious area of tissue is optically observed and potentially cancerous tissue is identified, they can be treated by several modalities.
|Images of the mouse model with HT-29 tumors after multimodal treatments (from left to right: control, PDT, PTT, PTT + chemo, and combined.|
Direct control of the laser light, which is delivered through an optical fiber and guided with the endoscope, can overcome many issues related to the penetration depth of light. Because colon cancers are normally located in superficial regions, the team’s system is less affected by the penetration depth problem of light in comparison with other tumor cases.
The results of the experiments were startling. After a two-week treatment plan, the tumors significantly decreased on the mouse model. However, when tumors were treated without injecting nanoparticles or using chemotherapy drugs, the tumor volume increased. The combined therapy group exhibited a marked decrease in the tumor volume.
|Summary of tumor volume changes and corresponding tumor images seen in the previous image.|
Multifunctional endoscope systems have the potential to reduce the procedure time and improve the efficiency of minimally invasive surgical procedures for colon cancer treatment. Furthermore, efficient therapy can contribute to the excellent oncologic and economic yield for various gastrointestinal cancers or precancerous lesions in the future.
Full details of the work appear in the journal Nature Communications; for more information, please visit http://dx.doi.org/10.1038/ncomms10059.
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