https://scholar.dgist.ac.kr/handle/20.500.11750/896 2026-04-04T12:01:39Z https://scholar.dgist.ac.kr/handle/20.500.11750/59946 Title: Automation in microinjection for zebrafish pericardial space with image-based motion control and batch agarose microplate Author(s): Lee, Hyuk-Jin; Lee, Hyun-Kyu; Lee, Sang-Won; Son, Ye-Won; Shin, Jun-Nyeong; Kim, Sohee Abstract: Microinjection enables the precise delivery of substances into specific areas of small animals, such as zebrafish, whose xenograft models can be a promising platform for developing rapid and personalized cancer therapies. However, manual microinjection exhibits experimental variability and low reproducibility, as it relies on the expertise of researchers. To address these problems, automated microinjection systems have been developed in recent years. In this study, we propose a microrobotic system based on an image recognition AI model that extracts key feature points to define the pericardial space in zebrafish larvae at 2 days post-fertilization. Using the geometric relationships among feature points, the system optimizes the glass capillary insertion motion for precise microinjection. We also introduced a batch agarose microplate that prevents dehydration while stabilizing the larvae, which improved the survival rate compared to the conventional plate (log-rank test, p < 0.0001). The proposed automation system achieved success rates of 80.8% (n = 1129) for microinjection and a 92.1% (n = 1143) for survival. Moreover, we successfully injected colorectal cancer cell lines (HCT116 and SW620) into the pericardial space, resulting in an engraftment success rate of 96.2% (n = 610). Our system exhibits higher success rates and reproducibility compared to manual microinjection, allowing even inexperienced researchers to perform stable injections. These results demonstrate that our system effectively enhances the efficiency and reproducibility of experiments involving zebrafish-based cancer research and xenograft model generation. 2025-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59061 Title: Optimized Coil Design for Enhanced Electric Field Induction in Peripheral Nerve Stimulation Author(s): Park, Jaeu; Lee, Kyeong Jae; Nagwade, Pritish; Jeong, Jinwoong; Park, Jeong Hoan; Choi, Hongsoo; Kim, Sohee; Lee, Sanghoon Abstract: Peripheral nerve electrical stimulation is widely used for the treatment of neuropathic pain and neural regeneration. However, it often induces adverse biological reactions and unintended activation of surrounding neural tissues. As an alternative, peripheral nerve magnetic stimulation offers a promising, less invasive approach that enables targeted nerve stimulation without direct tissue contact. Despite its potential, it is constrained by the bulkiness of coils and excessive heat generation due to the high currents required. To address these limitations, we conducted a study on coil design optimized for peripheral nerve modulation. Our approach, supported by simulations and animal experiments, focused on optimizing coil geometry to maximize the induced electric field gradient. Among various designs, a four-leaf rhombus-shaped coil demonstrated the highest gradient at the center of the interface. In rat sciatic nerve experiments, this coil, driven by a rectangular pulse with a 200 μs rise time and 25 V amplitude, successfully elicited compound muscle action potentials in both the tibial anterior and gastrocnemius muscles. This study presents design guidelines for peripheral nerve stimulation (PNS) coils based on magnetic stimulation as an alternative to conventional electrical stimulation. The proposed approach may serve as a foundation for the development of advanced, miniaturized, and energy-efficient neural stimulation coils. © 2025 Elsevier B.V., All rights reserved. 2025-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59060 Title: Neurotoxic effects of endosulfan on zebrafish (Danio rerio): Cognitive impairments, metallomic alterations, and impact of donepezil treatment Author(s): Kim, Chaeeun; Kim, Ho-jin; Kim, Donghyeon; Shin, Junnyeong; Kim, Sohee; Lee, Sung-Eun Abstract: Endosulfan is classified as a persistent organic pollutant with a ban on use globally, yet it continues to be detected in various environmental compartments. In this study, we used technical endosulfan (with a 7:3 ratio of α-endosulfan to β-endosulfan) to assess its neurotoxic effects on aquatic organisms, particularly adult zebrafish (Danio rerio). Adult zebrafish were exposed to concentrations ranging from 0 to 2.5 μg/L for 96 h, and their power spectral density was measured using an electroencephalogram (EEG). EEG analysis revealed ictal-like activity in zebrafish exposed to 0.5 μg/L of endosulfan. At the 1.0 μg/L concentration, power spectral densities of all frequency bands increased dramatically in the endosulfan-treated zebrafish, except for the delta band, indicating cognitive impairment. This study provides the first report quantifying the neurotoxic effects of endosulfan in fish. Metallomic analysis using ICP-OES and ICP-MS revealed a significant decrease in Fe levels at 2.5 μg/L, an increase in Mo at 1 μg/L, and elevated Pb levels at both 1 and 2.5 μg/L in the endosulfan-treated zebrafish, with these elemental alterations associated with cognitive impairment. Additionally, donepezil, a drug used to treat cognitive impairment induced by scopolamine, was ineffective in alleviating endosulfan-induced cognitive impairment and even exacerbated it. Therefore, endosulfan levels should be regularly monitored in environmental matrices, especially in aquatic environments, and its metabolites should also be tested for potential negative effects on cognitive processes, due to its adverse effects observed even at sufficiently low concentrations. © 2025 Elsevier B.V., All rights reserved. 2025-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/57225 Title: Epidural magnetic stimulation of the motor cortex using an implantable coil Author(s): Lee, Kyeong Jae; Jang, Jae-Won; Kim, June Sic; Kim, Sohee Abstract: Background: Magnetic stimulation, represented by transcranial magnetic stimulation (TMS), is used to treat neurological diseases. Various strategies have been explored to improve the spatial resolution of magnetic stimulation. While reducing the coil size is the most impactful approach for increasing the spatial resolution, it decreases the stimulation intensity and increases heat generation. Objective: We aim to demonstrate the feasibility of magnetic stimulation using an epidurally implanted millimeter-sized coil and that it does not damage the cortical tissue via heating even when a repetitive stimulation protocol is used. Methods: A coil with dimensions of 3.5 × 3.5 × 2.6 mm3 was epidurally implanted on the left motor cortex of rat, corresponding to the right hindlimb. Before and after epidural magnetic stimulation using a quadripulse stimulation (QPS) protocol, changes in the amplitude of motor evoked potentials (MEPs) elicited by a TMS coil were compared. Results: The experimental group showed an average increase of 88 % in MEP amplitude in the right hindlimb after QPS, whereas the MEP amplitude in the left hindlimb increased by 18 % on average. The control group showed no significant change in MEP amplitude after QPS in either hindlimb. The temperature changes at the coil surface remained <2 °C during repetitive stimulation, meeting the thermal safety limit for implantable medical devices. Conclusion: These results demonstrate the feasibility of epidural magnetic stimulation using an implantable coil to induce neuromodulation effects. This novel method is expected to be a promising alternative for focal magnetic stimulation with an improved spatial resolution and lowered stimulus current than previous magnetic stimulation methods. © 2024 The Authors 2024-08-31T15:00:00Z