{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T14:48:58Z","timestamp":1777560538588,"version":"3.51.4"},"reference-count":38,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,10]],"date-time":"2022-01-10T00:00:00Z","timestamp":1641772800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2020R1C1C1010505"],"award-info":[{"award-number":["2020R1C1C1010505"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"name":"the CABMC through funding by the Defense Acquisition Program Administration","award":["UD170030ID"],"award-info":[{"award-number":["UD170030ID"]}]},{"name":"BK21PLUS","award":["Creative Human Resource Education and Research Programs for ICT Convergence in the 4th Industrial Revolution"],"award-info":[{"award-number":["Creative Human Resource Education and Research Programs for ICT Convergence in the 4th Industrial Revolution"]}]},{"name":"Pusan National University Research","award":["2021"],"award-info":[{"award-number":["2021"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Spinal cord stimulation is a therapy to treat the severe neuropathic pain by suppressing the pain signal via electrical stimulation of the spinal cord. The conventional metal packaged and battery-operated implantable pulse generator (IPG) produces electrical pulses to stimulate the spinal cord. Despite its stable operation after implantation, the implantation site is limited due to its bulky size and heavy weight. Wireless communications including wireless power charging is also restricted, which is mainly attributed to the electromagnetic shielding of the metal package. To overcome these limitations, here, we developed a fully implantable miniaturized spinal cord stimulator based on a biocompatible liquid crystal polymer (LCP). The fabrication of electrode arrays in the LCP substrate and monolithically encapsulating the circuitries using LCP packaging reduces the weight (0.4 g) and the size (the width, length, and thickness are 25.3, 9.3, and 1.9 mm, respectively). An inductive link was utilized to wirelessly transfer the power and the data to implanted circuitries to generate the stimulus pulse. Prior to implantation of the device, operation of the pulse generator was evaluated, and characteristics of stimulation electrode such as an electrochemical impedance spectroscopy (EIS) were measured. The LCP-based spinal cord stimulator was implanted into the spared nerve injury rat model. The degree of pain suppression upon spinal cord stimulation was assessed via the Von Frey test where the mechanical stimulation threshold was evaluated by monitoring the paw withdrawal responses. With no spinal cord stimulation, the mechanical stimulation threshold was observed as 1.47 \u00b1 0.623 g, whereas the stimulation threshold was increased to 12.7 \u00b1 4.00 g after spinal cord stimulation, confirming the efficacy of pain suppression via electrical stimulation of the spinal cord. This LCP-based spinal cord stimulator opens new avenues for the development of a miniaturized but still effective spinal cord stimulator.<\/jats:p>","DOI":"10.3390\/s22020501","type":"journal-article","created":{"date-parts":[[2022,1,10]],"date-time":"2022-01-10T22:03:13Z","timestamp":1641852193000},"page":"501","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["A Fully Implantable Miniaturized Liquid Crystal Polymer (LCP)-Based Spinal Cord Stimulator for Pain Control"],"prefix":"10.3390","volume":"22","author":[{"given":"Seunghyeon","family":"Yun","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2115-7894","authenticated-orcid":false,"given":"Chin Su","family":"Koh","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea"}]},{"given":"Jungmin","family":"Seo","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea"}]},{"given":"Shinyong","family":"Shim","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea"}]},{"given":"Minkyung","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8289-564X","authenticated-orcid":false,"given":"Hyun Ho","family":"Jung","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9918-8095","authenticated-orcid":false,"given":"Kyungsik","family":"Eom","sequence":"additional","affiliation":[{"name":"Department of Electronics Engineering, College of Engineering, Pusan National University, Busan 46241, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2717-0101","authenticated-orcid":false,"given":"Jin Woo","family":"Chang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 03722, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7902-1223","authenticated-orcid":false,"given":"Sung June","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.neuron.2006.09.021","article-title":"Mechanisms of Neuropathic Pain","volume":"52","author":"Campbell","year":"2006","journal-title":"Neuron"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"71","DOI":"10.3171\/jns.1986.64.1.0071","article-title":"Spinal cord stimulation in peripheral arterial disease: A cooperative study","volume":"64","author":"Broseta","year":"1986","journal-title":"J. Neurosurg."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1109\/86.830945","article-title":"Muscle recruitment through electrical stimulation of the lumbo-sacral spinal cord","volume":"8","author":"Mushahwar","year":"2000","journal-title":"IEEE Trans. Rehabil. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1111\/j.1525-1403.2011.00395.x","article-title":"Incidence and Avoidance of Neurologic Complications with Paddle Type Spinal Cord Stimulation Leads","volume":"14","author":"Levy","year":"2011","journal-title":"Neuromodul. Technol. Neural Interface"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2574","DOI":"10.1097\/00007632-200211150-00034","article-title":"Spinal Cord Stimulation: Mechanisms of Action","volume":"27","author":"Oakley","year":"2002","journal-title":"Spine"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"840","DOI":"10.1016\/j.neuron.2017.01.012","article-title":"Leaky Gate Model: Intensity-Dependent Coding of Pain and Itch in the Spinal Cord","volume":"93","author":"Sun","year":"2017","journal-title":"Neuron"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.pain.2013.12.010","article-title":"Constructing and deconstructing the gate theory of pain","volume":"155","author":"Mendell","year":"2014","journal-title":"Pain"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/S1082-3174(96)80050-X","article-title":"Gate control theory: On the evolution of pain concepts","volume":"5","author":"Melzack","year":"1996","journal-title":"Pain Forum"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1111\/ner.12006","article-title":"High-Frequency Spinal Cord Stimulation for the Treatment of Chronic Back Pain Patients: Results of a Prospective Multicenter European Clinical Study","volume":"16","author":"Smet","year":"2013","journal-title":"Neuromodul. Technol. Neural Interface"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"851","DOI":"10.1097\/ALN.0000000000000774","article-title":"Novel 10-kHz High-frequency Therapy (HF10 Therapy) Is Superior to Traditional Low-frequency Spinal Cord Stimulation for the Treatment of Chronic Back and Leg Pain: The SENZA-RCT Randomized Controlled Trial","volume":"123","author":"Kapural","year":"2015","journal-title":"Anesthesiology"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1111\/ner.13037","article-title":"Patient-Specific Analysis of Neural Activation During Spinal Cord Stimulation for Pain","volume":"23","author":"Lempka","year":"2020","journal-title":"Neuromodul. Technol. Neural Interface"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"103","DOI":"10.3121\/cmr.2008.813","article-title":"Spinal cord stimulation as a treatment option for intractable neuropathic cancer pain","volume":"6","author":"Yakovlev","year":"2008","journal-title":"Clin. Med. Res."},{"key":"ref_13","unstructured":"(2021, September 26). PRIMEADVANCEDTM Multi-Program Neurostimulator Implant Manual. Available online: http:\/\/www.neuromodulation.ch\/sites\/default\/files\/pictures\/prime_advanced_implant_manual.pdf."},{"key":"ref_14","unstructured":"(2021, September 26). PrecisionTM M8 Adapter\u2014Directions for Use. Available online: https:\/\/www.bostonscientific.com\/content\/dam\/Manuals\/us\/current-rev-en\/90893429-09RevA_Precision_M8_Adapter_DFU_en-US_S.pdf."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/0304-3959(94)90047-7","article-title":"Perception threshold and electrode position for spinal cord stimulation","volume":"59","author":"He","year":"1994","journal-title":"Pain"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"642","DOI":"10.1016\/j.wneu.2013.01.040","article-title":"Burst Spinal Cord Stimulation for Limb and Back Pain","volume":"80","author":"Plazier","year":"2013","journal-title":"World Neurosurg."},{"key":"ref_17","unstructured":"(2021, September 26). Physician Implant Manual 11051 Rev A, Available online: https:\/\/www.accessdata.fda.gov\/cdrh_docs\/pdf13\/P130022d.pdf."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1111\/pme.12294","article-title":"Sustained Effectiveness of 10 kHz High-Frequency Spinal Cord Stimulation for Patients with Chronic, Low Back Pain: 24-Month Results of a Prospective Multicenter Study","volume":"15","author":"Smet","year":"2014","journal-title":"Pain Med."},{"key":"ref_19","first-page":"E671-4","article-title":"Late Extrusion of an Implantable Pulse Generator of a Spinal Cord Stimulator","volume":"19","author":"Rabi","year":"2016","journal-title":"Pain Physician"},{"key":"ref_20","unstructured":"Lorence, M.W., and Pesheck, P.S. (2020). Shielding and field modification of thick metal films. Woodhead Publishing in Materials, Woodhead Publishing."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2665","DOI":"10.1016\/j.apsusc.2005.03.206","article-title":"Selective metal pattern formation and its EMI shielding efficiency","volume":"252","author":"Lee","year":"2006","journal-title":"Appl. Surf. Sci."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1109\/TDMR.2005.859033","article-title":"MRI and implanted medical devices: Basic interactions with an emphasis on heating","volume":"5","author":"Nyenhuis","year":"2005","journal-title":"IEEE Trans. Device Mater. Reliab."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2045","DOI":"10.1109\/TBME.2010.2043102","article-title":"Numerical Model for Estimating RF-Induced Heating on a Pacemaker Implant During MRI: Experimental Validation","volume":"57","author":"Mattei","year":"2010","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"668","DOI":"10.1259\/dmfr\/17778370","article-title":"Radiofrequency heating and magnetically induced displacement of dental magnetic attachments during 3.0 T MRI","volume":"41","author":"Miyata","year":"2012","journal-title":"Dentomaxillofac. Radiol."},{"key":"ref_25","first-page":"189","article-title":"Liquid crystal polymer (LCP), an attractive substrate for retinal implant","volume":"24","author":"Jeong","year":"2012","journal-title":"Sens. Mater."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1108\/03056129610799958","article-title":"Controlled thermal expansion printed wiring boards based on liquid crystal polymer dielectrics","volume":"22","author":"Jayaraj","year":"1994","journal-title":"Circuit World"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"992","DOI":"10.1109\/8.410216","article-title":"A low cost multichip packaging technology for monolithic microwave integrated circuits","volume":"43","author":"Jayaraj","year":"1995","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Jobb\u00e1gy, \u00c1. (2012). Challenges for the Future Neuroprosthetic Implants B. Proceedings of the 5th European Conference of the International Federation for Medical and Biological Engineering, Springer.","DOI":"10.1007\/978-3-642-23508-5"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2085","DOI":"10.1109\/TBME.2012.2196274","article-title":"A Flexible Depth Probe Using Liquid Crystal Polymer","volume":"59","author":"Lee","year":"2012","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_30","first-page":"243","article-title":"High charge storage capacity electrodeposited iridium oxide film on liquid crystal polymer-based neural electrodes","volume":"28","author":"Shin","year":"2016","journal-title":"Sens. Mater."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"5859","DOI":"10.1167\/iovs.09-3743","article-title":"Development of Microelectrode Arrays for Artificial Retinal Implants Using Liquid Crystal Polymers","volume":"50","author":"Lee","year":"2009","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"982","DOI":"10.1109\/TBME.2014.2377197","article-title":"A Miniaturized, Eye-Conformable, and Long-Term Reliable Retinal Prosthesis Using Monolithic Fabrication of Liquid Crystal Polymer (LCP)","volume":"62","author":"Jeong","year":"2015","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4545","DOI":"10.1021\/nn401246y","article-title":"In Vivo Silicon-Based Flexible Radio Frequency Integrated Circuits Monolithically Encapsulated with Biocompatible Liquid Crystal Polymers","volume":"7","author":"Hwang","year":"2013","journal-title":"ACS Nano"},{"key":"ref_34","first-page":"497","article-title":"A handheld neural stimulation controller for avian navigation guided by remote control","volume":"30","author":"Shim","year":"2019","journal-title":"Biomed. Mater. Eng."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"66014","DOI":"10.1088\/1741-2560\/13\/6\/066014","article-title":"Nerve cuff electrode using embedded magnets and its application to hypoglossal nerve stimulation","volume":"13","author":"Seo","year":"2016","journal-title":"J. Neural Eng."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/S0304-3959(00)00276-1","article-title":"Spared nerve injury: An animal model of persistent peripheral neuropathic pain","volume":"87","author":"Decosterd","year":"2000","journal-title":"Pain"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"25004","DOI":"10.1088\/1741-2560\/13\/2\/025004","article-title":"Long-term evaluation of a liquid crystal polymer (LCP)-based retinal prosthesis","volume":"13","author":"Jeong","year":"2016","journal-title":"J. Neural Eng."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"66024","DOI":"10.1088\/1741-2552\/aae39d","article-title":"Long-term recording reliability of liquid crystal polymer \u00b5ECoG arrays","volume":"15","author":"Woods","year":"2018","journal-title":"J. Neural Eng."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/2\/501\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T14:01:53Z","timestamp":1760364113000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/2\/501"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,1,10]]},"references-count":38,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["s22020501"],"URL":"https:\/\/doi.org\/10.3390\/s22020501","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,1,10]]}}}