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Wireless pressure sensor integrated with a 3D printed polymer stent for smart health monitoring
Park, Jongsung,Kim, Ji-Kwan,Kim, Dong-Su,Shanmugasundaram, Arunkumar,Park, Su A,Kang, Sohi,Kim, Sung-Ho,Jeong, Myung Ho,Lee, Dong-Weon Elsevier 2019 Sensors and actuators. B Chemical Vol.280 No.-
<P><B>Abstract</B></P> <P>The primary objective of this study was to deploy a promising wireless pressure sensor system capable of monitoring real-time biological signals in an experimental object. MEMS-based micromachining technology was used to fabricate the proposed SU-8 wireless pressure sensor. The sensor utilizes a capacitor-inductor resonant circuit that can operate the sensor without any external power supply. The variable capacitor in the pressure sensor is designed to change the resonance frequency (130, 183 MHz) in response to applied pressure. The fabricated wireless pressure sensor was integrated into a polymer-based smart stent to minimize the discomfort of medication administration and hospital visits. A 3D bio-printing-based manufacturing technique was employed for the production of a smart polymer stent with complicated shapes. The proposed method is considerably more comfortable than the conventional metal stents fabrication process. The polymer smart stent made of the biocompatible polycaprolactone (PCL) material which can be fully absorbed by the body after a medication period. After integrating the fabricated wireless pressure sensor with the polymer smart stent, various basic experiments such as the working distance of the sensor were performed using a simple experimental setup. The biocompatibility of the proposed polymer stent and the wireless pressure sensor was also successfully confirmed using an experimental animal. The preliminary investigation results indicate that the proposed wireless sensor can be used to obtain necessary information in various parts of the human body as well as the stent.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fabrication of SU-8 based wireless pressure sensor for battery-less operation. </LI> <LI> Manufacturing of biodegradable polymer stent using 3D printing technique. </LI> <LI> Integration of wireless pressure sensor into polymer stent for real-time blood pressure monitoring. </LI> <LI> Verification of the biocompatibility of smart stent and its operation with experimental animals. </LI> <LI> Continuous measurement of blood pressure change in animals for more than 3 months. </LI> </UL> </P>
Finite Element Analysis and Mechanical Assessment for the Constraint of Total Knee Replacement
Kwan-Su Kang,Taegon Jung 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.25 No.4
The constraint level of TKR is essential for ensuring product performance to prevent knee joint dislocation. Computer modeling and simulation (CM&S) technology is widely used in the medical device industry due to its advantages such as reducing testing time and costs. However, there is a lack of research on the constraint level of TKR according to the size and flexion angle of the femoral component. In this study, the constraint levels of AP draw, ML shear, and rotary laxity were tested according to the size and flexion angle of TKR products using finite element analysis. A TKR model was constructed using a 3D scanner, and a finite element model with mechanical testing and error rates of 2.49% and 3.00% was developed through AP draw testing. In AP draw, as the size of TKR decreases, the constraint level increases by about 3.6%, and rotary laxity also increases by about 1.3%. In all tests, the constraint level increased as the bending angle of the femoral component increased. We found that the curvature and contact area of a TKR influenced the constraint level. Through this study, it is believed that CM&S technolaogy can be widely used in evaluating the unique performance of medical devices.
Kang, Ki-Kwan,Hur, Hoon,Byun, Cheul Su,Kim, Young Bae,Han, Sang-Uk,Cho, Yong Kwan The Korean Gastric Cancer Association 2014 Journal of gastric cancer Vol.14 No.1
Purpose: The role of peritoneal washing cytology in determining further treatment strategies after surgery for gastric cancer remains unclear. One reason for this is the fact that optimal procedures to increase the accuracy of predicting peritoneal metastasis have not been established. The aim of this study was to evaluate the efficacy of cytology using samples harvested from two different abdominal cavity sites during gastric cancer surgery. Materials and Methods: We prospectively recruited 108 patients who were clinically diagnosed with locally advanced gastric cancer (higher than cT1 stage disease). Peritoneal washing fluids were collected from the pouch of Douglas and the subphrenic area. Patients were prospectively followed up for 2 years to determine the recurrence and survival rates. Results: Thirty-three patients dropped out of the study for various reasons, so 75 patients were included in the final analysis. Seven patients (9.3%) showed positive cytology findings, of whom, three showed peritoneal recurrence. Tumor size was the only factor associated with positive cytology findings (P=0.037). The accuracy and specificity of cytology for predicting peritoneal recurrence were 90.1% and 94.2%, respectively, whereas the sensitivity was 50.0%. The survival rate did not differ between patients with positive cytology findings and those with negative cytology findings (P=0.081). Conclusions: Peritoneal washing cytology using samples harvested from two different sites in the abdominal cavity was not able to predict peritoneal recurrence or survival in gastric cancer patients. Further studies will be required to determine whether peritoneal washing cytology during gastric cancer surgery is a meaningful procedure.
마그네트론 스퍼터링 시스템을 이용한 정형외과용 PEEK의 타이타늄/하이드록시아파타이트 이중 코팅층의 표면 특성 분석
강관수(Kwan-Su Kang),정태곤(Tae-Gon Jung),양재웅(Jae-Woong Yang),우수헌(Su-Heon Woo),박태현(Tea-Hyun Park),정용훈(Yong-Hoon Jeong) 한국표면공학회 2018 한국표면공학회지 Vol.51 No.3
In this study, we have fabricated pure titanium (Ti)/hydroxyapatite (HA) double layer coating on medical grade PEEK from magnetron sputtering system, an investigation was performed whether the surface can be had more improve bio-active for orthopedi/dental applications than that of non-coated one. Pure Ti and HA coating layer were obtained by a radio-frequency and direct current power magnetron sputtering system. The microstructures surface, mechanical properties and wettability of the pure Ti/HA double layer deposited on the PEEK were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), nano-indentation, and contact angle test. According to the EDS and XRD results, the composition and crystal structure of pure Ti and HA coated surface were verified. The elastic modulus and hardness value were increased by pure Ti and HA coating, and the pure Ti/HA double layer coating surface has the highest value. The contact angle showed higher value for pure Ti/HA double layered coating specimens than that of non-coated (PEEK) surface.
Kim, Su Kang,Seok, Hosik,Park, Hae Jeong,Han, Kyuup,Kang, Sang Wook,Ban, Ju Yeon,Jung, Hee-Jae,Kim, Kwan-Il,Lee, Beom-Joon,Kim, Jinju,Chung, Joo-Ho International Scientific Literature, Inc. 2017 Medical science monitor Vol.23 No.-
<P><B>Background</B></P><P>Secretoglobin family 3A member 2 (SCGB3A2) plays an important role in secreting lung surfactant protein, which is a downstream target of thyroid transcription factor.</P><P><B>Material/Methods</B></P><P>We investigated whether single-nucleotide polymorphisms (SNPs) of SCGB3A2 gene contribute to susceptibility to asthma. To explore this possible association, 2 promoter SNPs (rs6882292, 659 G/A and rs1368408, −112 G/A) and missense SNP (rs151333009, stop codon) were tested in <I>SCGB3A2</I> gene in 101 asthma patients and 377 healthy control subjects. SNPStats was used to obtain odds ratio (OR), 95% confidence intervals (CI), and P value adjusted for age and sex as covariables. Logistic regression method in each model (dominant, recessive, and log-additive) was applied to analyze genetic data.</P><P><B>Results</B></P><P>rs151333009 SNP showed a monomorphic genotype. Two promoter SNPs (rs6882292, −659 G/A and rs1368408, −112 G/A) showed significant association with asthma (rs6882292, OR=2.66, 95% CI=1.42–5.01, p=0.0033 in dominant model, OR=2.45, 95% CI=1.33–4.54, p=0.0055 in log-additive model; rs1368408, OR=1.59, 95% CI=1.02–2.49, p=0.041 in dominant model, OR=3.02, 95% CI=1.15–7.90, p=0.03 in recessive model, OR=1.63, 95% CI=1.63, 95% CI=1.12–2.37, p=0.012 in log-additive model).</P><P><B>Conclusions</B></P><P>These results suggest that the promoter SNPs (rs6882292 and rs1368408) of <I>SCGB3A2</I> gene may contribute to susceptibility to asthma in a Korean population.</P>
TiN 및 DLC 코팅된 척추경나사못시스템 수술기구의 기계적 안정성 분석
강관수(Kwan-Su Kang),정태곤(Tae-Gon Jung),양재웅(Jae-Woong Yang),우수헌(Su-Heon Woo),박태현(Tea-Hyun Park),정용훈(Yong-Hoon Jeong) 한국표면공학회 2019 한국표면공학회지 Vol.52 No.3
Durability of instrument is one of the most important factor to ensure accurate treatment and decrease failure for the orthopedic surgical operation. Normally, a set-screw driver tip has been processed with hard coating for their higher durability and wear resistance. And several surface modification methods were obtained such as titanium nitride (TiN) coating, diamond like carbon coating, other nitriding, and etc. In this study, we have surface modified on set-screw driver tip with TiN and DLC, investigated whether the TiN and DLC coatings affect the mechanical properties and durability of the set-screw driver tip in the pedicle screw system. The surface morphologies were observed with scanning-electron microscopy (SEM), and the static/dynamic torsional properties were investigated with universal testing machine based on ASTM F543. Coating thickness of each coatings were commonly around 1oC. Static torsional stiffness, and ultimate torque values for DLC and TiN coated samples were significantly higher than those of non-coated sample by the pared T-test. Surface morphology of after the dynamic torsional test was more clean with less scratch or friction traces from DLC coating than that of TiN coating and non-coated sample.