Eric L. Wisotzky, Sophie Beckmann, Peter Eisert, Lasse Renz-Kiefel, Anna Hilsmann, Sebastian Lünse, René Mantke
Abstract Surgical phase recognition is an important aspect of surgical workflow analysis, as it allows an automatic analysis of the performance and efficiency of surgical procedures. A big challenge for training a neural network for surgical phase recognition is the availability of training data and the large (visual) variability in procedures of different surgeons. Hence, a network must be able to generalize to new data. In this paper, we present an adaptation of a Temporal Convolutional Network for surgical phase recognition in order to ensure the generalization of the network to new scenes with different conditions on the example of cholecystectomy. We used publicly available datasets of 104 surgeries from four different centers for training. The results showed that the network was able to generalize to new scenes and we obtained recognition results with accuracy up to 82% on our own six captured surgeries, performed in a different hospital. This performance is similar for test data from the hospitals of the training data, suggesting that the network can well generalize to new surgical rooms and surgeons. The findings have important implications for the development of automated surgical decision support systems that can be applied in a variety of real-world surgical settings.
{"title":"Surgical Phase Recognition for different hospitals","authors":"Eric L. Wisotzky, Sophie Beckmann, Peter Eisert, Lasse Renz-Kiefel, Anna Hilsmann, Sebastian Lünse, René Mantke","doi":"10.1515/cdbme-2023-1079","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1079","url":null,"abstract":"Abstract Surgical phase recognition is an important aspect of surgical workflow analysis, as it allows an automatic analysis of the performance and efficiency of surgical procedures. A big challenge for training a neural network for surgical phase recognition is the availability of training data and the large (visual) variability in procedures of different surgeons. Hence, a network must be able to generalize to new data. In this paper, we present an adaptation of a Temporal Convolutional Network for surgical phase recognition in order to ensure the generalization of the network to new scenes with different conditions on the example of cholecystectomy. We used publicly available datasets of 104 surgeries from four different centers for training. The results showed that the network was able to generalize to new scenes and we obtained recognition results with accuracy up to 82% on our own six captured surgeries, performed in a different hospital. This performance is similar for test data from the hospitals of the training data, suggesting that the network can well generalize to new surgical rooms and surgeons. The findings have important implications for the development of automated surgical decision support systems that can be applied in a variety of real-world surgical settings.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maxim Fenko, Constantin Wiesener, Rima Fanaei Pirlar, Andrej Trampuz, Markus Valtin, Thomas Schauer
Abstract Introduction: Biofilms are bacterial communities that transform into a state enclosed in an extracellular polymeric substance, which makes them less susceptible to antibiotics. Those bacterial formations often develop on metal implants and cause chronic infections. Due to the severely reduced impact of antibiotics against biofilms, the effect of electric stimulation (on its own and in combination with antimicrobials) needs to be further observed, as available studies indicate a positive effect. Methods: Therefore, this work examined the development of a six-channel current-controlled stimulation setup, which enables further in vitro research on the effects of electric stimulation on biofilms. The setup controls the desired stimulation current through the load to counteract electrochemical processes, which constantly change its resistive and capacitive properties. Results: Each channel of the stimulator is able to operate within an amplitude range of 50 A to 1 mA, a frequency range of 0 Hz to 1 kHz, and a pulse width range of 50 s to 1 ms. The current control provides a sufficient rise time of 3.3 s for three different stimulation modes: constant direct current (DC), pulsed DC, and biphasic-pulsed alternating current (AC). Furthermore, a graphical user interface enables the user to regulate and observe the stimulation on a computer to which the stimulator device is connected. Conclusion: The achieved variety of stimulation parameters in one device makes it possible to analyze the effect of different stimulation paradigms on biofilms and therefore enables more in vitro research which is inevitable to develop a sufficient treatment for patients with biofilm-infected implants.
{"title":"Development of a current controlled stimulation setup for investigating the effect of electrical currents on implant infections caused by biofilms","authors":"Maxim Fenko, Constantin Wiesener, Rima Fanaei Pirlar, Andrej Trampuz, Markus Valtin, Thomas Schauer","doi":"10.1515/cdbme-2023-1028","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1028","url":null,"abstract":"Abstract Introduction: Biofilms are bacterial communities that transform into a state enclosed in an extracellular polymeric substance, which makes them less susceptible to antibiotics. Those bacterial formations often develop on metal implants and cause chronic infections. Due to the severely reduced impact of antibiotics against biofilms, the effect of electric stimulation (on its own and in combination with antimicrobials) needs to be further observed, as available studies indicate a positive effect. Methods: Therefore, this work examined the development of a six-channel current-controlled stimulation setup, which enables further in vitro research on the effects of electric stimulation on biofilms. The setup controls the desired stimulation current through the load to counteract electrochemical processes, which constantly change its resistive and capacitive properties. Results: Each channel of the stimulator is able to operate within an amplitude range of 50 A to 1 mA, a frequency range of 0 Hz to 1 kHz, and a pulse width range of 50 s to 1 ms. The current control provides a sufficient rise time of 3.3 s for three different stimulation modes: constant direct current (DC), pulsed DC, and biphasic-pulsed alternating current (AC). Furthermore, a graphical user interface enables the user to regulate and observe the stimulation on a computer to which the stimulator device is connected. Conclusion: The achieved variety of stimulation parameters in one device makes it possible to analyze the effect of different stimulation paradigms on biofilms and therefore enables more in vitro research which is inevitable to develop a sufficient treatment for patients with biofilm-infected implants.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Wearable emotion recogniton system is essential in identifying mental health disorders by early detection and continuous monitoring of human emotions to provide proper treatment care. Electrocardiogram (ECG) signals can be used for emotion recognition for its noninvasiveness and easy usability. In this study, Detrended Fluctuation Analysis (DFA) and Extreme Gradient Boost (XG Boost) classifier is used to classify the scary and boring emotion from the ECG signals. For this, ECG signal corresponding to these emotions are obtained from public database. The preprocessing is performed by adding the video IDs to the signal and annotating it. This preprocessed signal is subjected to DFA to understand the power-law correlations and similarity property. Further, from the power law correlations, features namely Hurst exponent and DFA intercept are extracted. These features are subjected to XG Boost classifier to differentiate the two emotions. Results shows that the log-log plot of power law correlation is linear in nature which indicates that ECG signals of both the emotions have long range correlations and self-similarity property. The extracted scaling exponent indicates variations between scary and boring with a mean and standard deviation of 0.81±0.13 and 0.68±0.07 respectively. Similarly, DFA intercept provides mean and standard deviation for scary and boring 0.15±0.06 and 0.17±0.07 respectively, showing less variability in the ECG signal. XG Boost classifier gives accuracy of 80.5% for classifying scary and boring emotion. Thus, the proposed approach can be used for wearable emotion recognition system to differentiate scary and boring emotion.
{"title":"Quantitative ECG based emotion state recognition using Detrended Fluctuation Analysis","authors":"Meena Anandan, Pandiyarasan Veluswamy, Rohini Palanisamy","doi":"10.1515/cdbme-2023-1176","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1176","url":null,"abstract":"Abstract Wearable emotion recogniton system is essential in identifying mental health disorders by early detection and continuous monitoring of human emotions to provide proper treatment care. Electrocardiogram (ECG) signals can be used for emotion recognition for its noninvasiveness and easy usability. In this study, Detrended Fluctuation Analysis (DFA) and Extreme Gradient Boost (XG Boost) classifier is used to classify the scary and boring emotion from the ECG signals. For this, ECG signal corresponding to these emotions are obtained from public database. The preprocessing is performed by adding the video IDs to the signal and annotating it. This preprocessed signal is subjected to DFA to understand the power-law correlations and similarity property. Further, from the power law correlations, features namely Hurst exponent and DFA intercept are extracted. These features are subjected to XG Boost classifier to differentiate the two emotions. Results shows that the log-log plot of power law correlation is linear in nature which indicates that ECG signals of both the emotions have long range correlations and self-similarity property. The extracted scaling exponent indicates variations between scary and boring with a mean and standard deviation of 0.81±0.13 and 0.68±0.07 respectively. Similarly, DFA intercept provides mean and standard deviation for scary and boring 0.15±0.06 and 0.17±0.07 respectively, showing less variability in the ECG signal. XG Boost classifier gives accuracy of 80.5% for classifying scary and boring emotion. Thus, the proposed approach can be used for wearable emotion recognition system to differentiate scary and boring emotion.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Henrik Wolframm, Johannes Hoffmann, Ralf Burgardt, Eric Elzenheimer, Gerhard Schmidt, Michael Höft
Abstract Accurate calibration is key for any reliable sensor system. Magnetoelectric (ME) sensors, in particular, are influenced in their operating point by external parameters such as the Earth’s magnetic field or the ambient temperature. In this paper, we introduce a new planar coil design for the generation of a magnetic test field within the plane of the ME sensor. Furthermore, we implemented a method for measuring the sensor behaviour using a short-term magnetic noise signal. The combination of the printed circuit board (PCB) coil and the accelerated sensor characterization method allows the sensor system to be calibrated at the measurement site (in situ) without the need for laboratory equipment. We can show that the presented method for calibration achieves high-quality results in 10 seconds for a sensor affected by external interference fields.
{"title":"PCB Coil Enables In Situ Calibration of Magnetoelectric Sensor Systems","authors":"Henrik Wolframm, Johannes Hoffmann, Ralf Burgardt, Eric Elzenheimer, Gerhard Schmidt, Michael Höft","doi":"10.1515/cdbme-2023-1142","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1142","url":null,"abstract":"Abstract Accurate calibration is key for any reliable sensor system. Magnetoelectric (ME) sensors, in particular, are influenced in their operating point by external parameters such as the Earth’s magnetic field or the ambient temperature. In this paper, we introduce a new planar coil design for the generation of a magnetic test field within the plane of the ME sensor. Furthermore, we implemented a method for measuring the sensor behaviour using a short-term magnetic noise signal. The combination of the printed circuit board (PCB) coil and the accelerated sensor characterization method allows the sensor system to be calibrated at the measurement site (in situ) without the need for laboratory equipment. We can show that the presented method for calibration achieves high-quality results in 10 seconds for a sensor affected by external interference fields.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Introduction. Computational models of optic nerve stimulation can allow to estimate the neural response of optic nerve fibers electrical stimulation and thus can be exploited to tune stimulation parameters to obtain a specific target perception. In principle, such tuning should be performed in an automatic way, so that the chosen stimulation parameters minimize some given cost function related to the quality of resulting the visual perception, but the use of such automatic methods is still under study and no satisfactory solution is available yet. In the absence of automatic methods, stimulation parameters are customarily set via manual tuning, which can be extremely time-consuming if performed in a non-principled way. Methods. We build biophysically-accurate hybrid models of monopolar and bipolar electrical stimulation of optic nerve fibers to study how the fibers firing rates depend upon the stimulation parameters. Results. In the case of monopolar sinusoidal stimulation of optic nerve fibers, we show that the amplitude of stimulation controls the size of the recruited cluster of fibers, and that the frequency controls their firing rate, independently. Instead, for bipolar stimulation, we show that when cross-talk is non negligible it is very difficult to obtain rules of thumb linking the firing rate of target fibers to stimulation parameters. Conclusion. We show that, if the stimulation amplitude is kept such that neighboring stimulating sites do not produce cross-talk, it is possible to reconstruct visual scenes “pixel-by-pixel” without needing any optimization process. If on the contrary current steering is required and cross-talk is non negligible, then it is very difficult to obtain rules of thumb and the development and use of automatic optimization techniques should be preferable.
{"title":"Decoupling the effects of varying amplitude and frequency in the electrical stimulation of optic nerve fibers","authors":"Simone Romeni, Gabriele Marino, Luca Pierantoni, Silvestro Micera","doi":"10.1515/cdbme-2023-1049","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1049","url":null,"abstract":"Abstract Introduction. Computational models of optic nerve stimulation can allow to estimate the neural response of optic nerve fibers electrical stimulation and thus can be exploited to tune stimulation parameters to obtain a specific target perception. In principle, such tuning should be performed in an automatic way, so that the chosen stimulation parameters minimize some given cost function related to the quality of resulting the visual perception, but the use of such automatic methods is still under study and no satisfactory solution is available yet. In the absence of automatic methods, stimulation parameters are customarily set via manual tuning, which can be extremely time-consuming if performed in a non-principled way. Methods. We build biophysically-accurate hybrid models of monopolar and bipolar electrical stimulation of optic nerve fibers to study how the fibers firing rates depend upon the stimulation parameters. Results. In the case of monopolar sinusoidal stimulation of optic nerve fibers, we show that the amplitude of stimulation controls the size of the recruited cluster of fibers, and that the frequency controls their firing rate, independently. Instead, for bipolar stimulation, we show that when cross-talk is non negligible it is very difficult to obtain rules of thumb linking the firing rate of target fibers to stimulation parameters. Conclusion. We show that, if the stimulation amplitude is kept such that neighboring stimulating sites do not produce cross-talk, it is possible to reconstruct visual scenes “pixel-by-pixel” without needing any optimization process. If on the contrary current steering is required and cross-talk is non negligible, then it is very difficult to obtain rules of thumb and the development and use of automatic optimization techniques should be preferable.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gerhard Schmidt, Erik Engelhardt, Eric Elzenheimer, Johannes Hoffman, Tobias Schmidt, Adrian Zaman, Norbert Frey
Abstract In this paper we present a novel noninvasive approach to estimate current densities in the heart from magnetocardiography. The proposed algorithm uses nested optimization to model current densities in equally-sized voxels of myocardial tissue. First-order Thiran all-pass filters are used to describe the propagation between voxels.We demonstrate feasibility of the algorithm for a noise-free single-layer simulation. However, challenges remain, such as addressing measurement noise and optimizing propagation velocity. Overall, this approach has the potential to complement or replace invasive catheter-based electrophysiological studies for localization of arrhythmogenic tissue.
{"title":"A Concept for Myocardial Current Density Estimation with Magnetoelectric Sensors","authors":"Gerhard Schmidt, Erik Engelhardt, Eric Elzenheimer, Johannes Hoffman, Tobias Schmidt, Adrian Zaman, Norbert Frey","doi":"10.1515/cdbme-2023-1023","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1023","url":null,"abstract":"Abstract In this paper we present a novel noninvasive approach to estimate current densities in the heart from magnetocardiography. The proposed algorithm uses nested optimization to model current densities in equally-sized voxels of myocardial tissue. First-order Thiran all-pass filters are used to describe the propagation between voxels.We demonstrate feasibility of the algorithm for a noise-free single-layer simulation. However, challenges remain, such as addressing measurement noise and optimizing propagation velocity. Overall, this approach has the potential to complement or replace invasive catheter-based electrophysiological studies for localization of arrhythmogenic tissue.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Seidler, Martin Pendzik, Arthur Hilbig, Philipp Sembdner, Stefan Holtzhausen, Kristin Paetzold-Byhain
Abstract In current implantology, calcium phosphate cement (CPC) is increasingly used. A special focus is given to CPC scaffolds, as they are suitable for cell settlement and growth due to their positive osteoconductive properties. The design of the scaffolds is of decisive importance for this. The value ranges of the geometric parameters of these scaffolds (e.g. path distance, path diameter), which are positive for both cell settlement and cell growth, are very small. Manufacturing deviations therefore have a significant impact on cell settlement and growth. The pasty manufacturing consistency can cause sagging at the path interstices of a layer immediately below, resulting in significant manufacturing deviations. A larger path distance and thus a larger path interstitial space promotes cell settlement, but at the same time increases the risk of CPC path shape inconsistency. This in turn can have a negative effect on cell settlement. Therefore, the aim of this paper is to investigate the discrepancies between the nominal and actual state at a path distance favourable to cell settlement on the basis of manufactured CPC scaffolds. In this context, geometric and manufacturing parameters of the shape deviation are to be identified and constructive design adaptations are to be derived on the basis of these. In addition, the effects of the shape and position deviations on the flow behaviour will be investigated.
{"title":"Investigation of manufacturing deviations of CPC scaffolds for improving the design process","authors":"Alexander Seidler, Martin Pendzik, Arthur Hilbig, Philipp Sembdner, Stefan Holtzhausen, Kristin Paetzold-Byhain","doi":"10.1515/cdbme-2023-1138","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1138","url":null,"abstract":"Abstract In current implantology, calcium phosphate cement (CPC) is increasingly used. A special focus is given to CPC scaffolds, as they are suitable for cell settlement and growth due to their positive osteoconductive properties. The design of the scaffolds is of decisive importance for this. The value ranges of the geometric parameters of these scaffolds (e.g. path distance, path diameter), which are positive for both cell settlement and cell growth, are very small. Manufacturing deviations therefore have a significant impact on cell settlement and growth. The pasty manufacturing consistency can cause sagging at the path interstices of a layer immediately below, resulting in significant manufacturing deviations. A larger path distance and thus a larger path interstitial space promotes cell settlement, but at the same time increases the risk of CPC path shape inconsistency. This in turn can have a negative effect on cell settlement. Therefore, the aim of this paper is to investigate the discrepancies between the nominal and actual state at a path distance favourable to cell settlement on the basis of manufactured CPC scaffolds. In this context, geometric and manufacturing parameters of the shape deviation are to be identified and constructive design adaptations are to be derived on the basis of these. In addition, the effects of the shape and position deviations on the flow behaviour will be investigated.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Klaus Kreuels, Carina Schemmer, Arnold Gillner, Maximilian Frederick Flesch, Arnold Gillner
Abstract This study presents a novel approach for threedimensional (3D) cell culture using a two-component system consisting of a 3D-printed scaffold structure combined with a perfusion channel. A polymeric scaffold structure with an overall size of 9 mm x 9 mm x 1 mm composed of a cubic lattice with a web thickness of 200 μm and pore size of 600 μm was 3D-printed using a hot UV-stereolithography (SLA) system. The perfusion channel with an inner diameter of 800 μm and channel wall pores of 300 μm for cell culture medium supply was 3D-printed with the same system and material. Scaffolds were investigated with respect to the printing accuracy by digital microscopy. Cytotoxicity of the materials was assessed using MTT-assay and Live/Dead staining. Scaffold were subsequently seeded with 3T3- fibroblasts within a fibrin-based hydrogel and then conditioned either statically or under passive perfusion using a hydrostatic pressure driven flow system. The results show that the scaffold structure and perfusion channel can be produced with high accuracy and stability allowing a supply of nutrient and oxygen via perfusion channel to the cells within the scaffold. This approach has potential for nutrient supply within larger constructs for tissue engineering and regenerative medicine applications.
本研究提出了一种三维(3D)细胞培养的新方法，该方法使用由3D打印支架结构和灌注通道组成的双组分系统。采用热紫外立体光刻(SLA)系统进行3d打印，制备了一种总尺寸为9mm x 9mm x 1mm的聚合物支架结构，该支架由立方晶格组成，腹板厚度为200 μm，孔径为600 μm。采用相同的体系和材料，3d打印出内径为800 μm、壁孔为300 μm的灌注通道供细胞培养基供应。用数码显微镜对支架的打印精度进行了研究。采用mtt法和活/死染色评估材料的细胞毒性。随后，将3T3-成纤维细胞植入基于纤维蛋白的水凝胶中，然后使用静水压力驱动流系统进行静态或被动灌注调节。结果表明，该支架结构和灌注通道的制备精度高，稳定性好，可使支架内细胞通过灌注通道获得营养和氧气供应。这种方法有潜力在组织工程和再生医学应用的更大结构中提供营养。
{"title":"3D-printed scaffolds with perfusable channels for low-cost large construct 3D cell culture","authors":"Klaus Kreuels, Carina Schemmer, Arnold Gillner, Maximilian Frederick Flesch, Arnold Gillner","doi":"10.1515/cdbme-2023-1166","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1166","url":null,"abstract":"Abstract This study presents a novel approach for threedimensional (3D) cell culture using a two-component system consisting of a 3D-printed scaffold structure combined with a perfusion channel. A polymeric scaffold structure with an overall size of 9 mm x 9 mm x 1 mm composed of a cubic lattice with a web thickness of 200 μm and pore size of 600 μm was 3D-printed using a hot UV-stereolithography (SLA) system. The perfusion channel with an inner diameter of 800 μm and channel wall pores of 300 μm for cell culture medium supply was 3D-printed with the same system and material. Scaffolds were investigated with respect to the printing accuracy by digital microscopy. Cytotoxicity of the materials was assessed using MTT-assay and Live/Dead staining. Scaffold were subsequently seeded with 3T3- fibroblasts within a fibrin-based hydrogel and then conditioned either statically or under passive perfusion using a hydrostatic pressure driven flow system. The results show that the scaffold structure and perfusion channel can be produced with high accuracy and stability allowing a supply of nutrient and oxygen via perfusion channel to the cells within the scaffold. This approach has potential for nutrient supply within larger constructs for tissue engineering and regenerative medicine applications.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stefan Siewert, Ariane Dierke, Thomas Stahnke, Swen Großmann, Christoph Brandt-Wunderlich, Laura Supp, Michael Stiehm, Andrea Bock, Klaus-Peter Schmitz, Paula Rosam, Marek Zygmunt
Abstract Fallopian tube occlusions represent one of the most common causes of female sterility. As an innovative treatment approach for affected persons, we previously presented the concept of a novel polymeric, self-expanding, and bioresorbable microstent. As a basis for microstent development, knowledge of the mechanical properties of the anatomical target structure represents a crucial requirement. The current work describes a methodological approach for the experimental determination of radial Fallopian tube compliance using optical coherence tomography. It could be shown that a quantitative assessment of the mechanical properties of porcine Fallopian tube samples - as a whole anatomical structure including the Tunica mucosa, the Tunica muscularis, and the Tunica serosa - is possible, using the described test setup. Future investigations on human samples will allow for valuable information regarding the structural-mechanical properties of the Fallopian tube. Therefore, the current work offers perspectives for the development of a novel gynecological microstent for the treatment of Fallopian tube occlusions.
{"title":"Radial compliance of porcine Fallopian tubes ex vivo – perspectives for the development of a gynecological microstent","authors":"Stefan Siewert, Ariane Dierke, Thomas Stahnke, Swen Großmann, Christoph Brandt-Wunderlich, Laura Supp, Michael Stiehm, Andrea Bock, Klaus-Peter Schmitz, Paula Rosam, Marek Zygmunt","doi":"10.1515/cdbme-2023-1147","DOIUrl":"https://doi.org/10.1515/cdbme-2023-1147","url":null,"abstract":"Abstract Fallopian tube occlusions represent one of the most common causes of female sterility. As an innovative treatment approach for affected persons, we previously presented the concept of a novel polymeric, self-expanding, and bioresorbable microstent. As a basis for microstent development, knowledge of the mechanical properties of the anatomical target structure represents a crucial requirement. The current work describes a methodological approach for the experimental determination of radial Fallopian tube compliance using optical coherence tomography. It could be shown that a quantitative assessment of the mechanical properties of porcine Fallopian tube samples - as a whole anatomical structure including the Tunica mucosa, the Tunica muscularis, and the Tunica serosa - is possible, using the described test setup. Future investigations on human samples will allow for valuable information regarding the structural-mechanical properties of the Fallopian tube. Therefore, the current work offers perspectives for the development of a novel gynecological microstent for the treatment of Fallopian tube occlusions.","PeriodicalId":10739,"journal":{"name":"Current Directions in Biomedical Engineering","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135394561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andreas Scherrieble, Elena Haab, Evi Held-Föhn, Carsten Linti, Michael Doser, Götz T. Gresser, Tobias Baumgartner, Claus G. Wandres
Abstract Hospital-acquired infections occur through microbial contamination of the surgical wound and can lead to severe complications. A significant transmission path is the aerogenic transmission, where pathogens stick to floating particles like skin scales or to air moisture. A novel porous airflow ring which is placed around the surgical field aims to overcome this by applying sterile air directly at the operation wound. The ring is provided with an air tight coating at the outer side and allows for fixation on the skin by an adhesive coating at the lower side. To evaluate its performance the airflow ring was placed in an atmosphere with nebulized suspension of Staphylococcus arlettae of a concentration of 5.0 x 10^5 CFU/ml resp. 5.0 x 10^6 CFU/ml within a box. The formation of bacterial colonies (CFU) on contact plates placed within the airflow ring was subsequently determined by visual counting after incubating at 37 °C for one day. CFU counts of the ventilated and the unventilated situation were compared. With the smaller inoculum, the introduction of bacteria into the inner site of the ring was completely prevented, whereas the contact plate of the unventilated ring resulted in 77 to 427 colonies in different trials. With the higher inoculum, the bacteria ingress was very strongly reduced by 99.7% respectively 99.9%. In conclusion the airflow ring shows a strong shielding effect for germs adhered to fog-sized water droplets. To clearly demonstrate the effect, the number of bacteria was greatly increased compared to reality in this setup. It was shown that it can withstand even conditions significantly worse than those encountered in an operating theatre. In order to demonstrate the effect in vivo, clinical trials have to be conducted to confirm the laboratory results.
医院获得性感染是通过外科伤口的微生物污染而发生的，可导致严重的并发症。一个重要的传播途径是空气传播，病原体附着在皮肤鳞片等漂浮颗粒或空气湿度上。一种新型的多孔气流环被放置在手术区域周围，旨在通过将无菌空气直接应用于手术伤口来克服这一问题。所述环在其外侧设有气密涂层，并允许在其下侧通过粘合剂涂层固定在皮肤上。为了评估其性能，将气流环放置在浓度为5.0 × 10^5 CFU/ml的葡萄球菌雾化悬浮液的气氛中。盒内5.0 x 10^6 CFU/ml。在37°C孵育1天后，通过目测计数测定放置在气流环内的接触板上菌落(CFU)的形成。比较通风与不通风情况下的CFU计数。较小的接种量完全阻止了细菌进入环内部位，而不通风环的接触板在不同的试验中产生了77 ~ 427个菌落。在较高的接种量下，细菌的进入率分别降低了99.7%和99.9%。综上所述，气流环对附着在雾状水滴上的细菌具有较强的屏蔽作用。为了清楚地证明这种效果，在这种设置中，细菌的数量大大增加了。研究表明，它甚至可以承受比手术室更恶劣的条件。为了证明在体内的效果，必须进行临床试验来确认实验室结果。
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