Bio-Medical Materials and Engineering - Volume 31, issue 4

Authors: Kambe, Yusuke | Ogino, Shuichi | Yamanaka, Hiroki | Morimoto, Naoki | Yamaoka, Tetsuji

Article Type: Research Article

Abstract: BACKGROUND: Adipose tissue engineering has been studied as an alternative to current options for breast reconstruction, such as lipofilling, flap reconstruction, and silicone implants. Previously, we demonstrated that a poly(L-lactic acid) mesh containing a collagen sponge, containing neither cells nor growth factors, could be filled with the regenerated adipose tissues when implanted in rodent models. However, the main factor contributing to adipogenesis remained unclear. OBJECTIVE: We aimed to clarify whether adipogenesis can be achieved by the space provided by the mesh or by the bioactivity of collagen. METHODS: A three-dimensional (3D) poly(lactic acid) (PLA) frame, which …was stiff enough to maintain its shape, was fabricated by 3D printing. The frame with (PLA+ColI) or without (PLA only) a type I collagen hydrogel was implanted in the inguinal region of rats for up to 12 months. Adipose tissue regeneration in the PLA only and PLA+ColI groups was evaluated histologically. RESULTS: The 3D PLA frame maintained its structure for 12 months in vivo and oil red O (ORO)-positive adipose tissues were regenerated in the frame. No significant difference in the ORO-positive area was detected between the PLA only and PLA+ColI groups. CONCLUSION: The space supported by the frame was a key factor in adipogenesis in vivo. Show more

Keywords: Adipogenesis, 3D printing, PLA, collagen hydrogel, internal space

DOI: 10.3233/BME-201103

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 4, pp. 203-210, 2020

Authors: Cavaco, Adriana | Durães, Luísa | Ramalho, Amílcar | Pais, Sandra

Article Type: Research Article

Abstract: BACKGROUND: Interfaces of transtibial prosthesis have an important role in the transmission of ground reaction forces, damping gait loads and tissue protection. OBJECTIVE: This work aims to study the influence of prosthesis interfaces on amputees’ gait and perception on pain, comfort and the overall interface/prosthesis system. METHODS: Commercial samples of three different interface materials were selected: block copolymer (Material I), silicone gel (Material II) and silicone elastomer (Material III). Using standardized prosthesis, four amputee subjects performed gait tests at three imposed cadences in a barometric platform. The subjects also filled in a questionnaire about their perception. …RESULTS: Material II presented the highest asymmetries of vertical ground reaction forces and was perceived as the most painful and uncomfortable. Material III led to the most symmetric load distribution between legs and was perceived as the most comfortable. Material I showed better overall biomechanical behavior and better subject’s perception. CONCLUSIONS: Material III showed appropriate characteristics for lower levels of activity for which it is recommended. Prescription of Material II should be rethought, as it is only adequate for specific and occasional situations. Material I should be considered adequate for both active and less active amputees. When correlating the subjects’ perception with the interface properties, we concluded that the mechanical properties are the most influential. Show more

Keywords: Limb prosthesis, gait analysis, transtibial amputees, materials testing, silicone, block copolymer

DOI: 10.3233/BME-206002

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 4, pp. 211-223, 2020

Authors: Elblbesy, Mohamed A. | Hanafy, Taha A. | Kandil, Bothaina A.

Article Type: Research Article

Abstract: BACKGROUND: The design and fabrication of hemocompatible and low-toxicity formulations remains a challenging task. Hydrogels are of considerable importance for biomedical applications since they are highly compatible with living tissue, both in vivo and in vitro. OBJECTIVE: The present study aimed to develop and evaluate the characterizations and in vitro hemocompatibility of a hydrogel using polyvinyl alcohol and gelatin with different concentrations. METHODS: The gelling process was realized by cross-linking the polyvinyl alcohol and gelatin. The morphological and structural examinations of the synthetic hydrogels were done by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). …The swelling behavior of the prepared hydrogels in water was evaluated. Prothrombin time, activated partial thromboplastin time, and thrombin time were measured, and a hemolysis test was done to evaluate the hemocompatibility of prepared hydrogels. RESULTS: The increase of the gelatin concentration in polyvinyl gelatin hydrogel increases the porosity and enhances the absorptivity of the prepared hydrogel. The measured hematological parameters indicated enhancement of hemocompatibility as the gelatin concentration was increased in the prepared hydrogel. CONCLUSIONS: The results obtained from this study confirm that gelatin was able to improve the properties of the polyvinyl alcohol–gelatin hydrogel and enhance the hemocompatibility. Thus, the prepared hydrogel could be used in a variety of biomedical applications. Show more

Keywords: Polyvinyl alcohol, gelatin, hemocompatibility

DOI: 10.3233/BME-201096

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 4, pp. 225-234, 2020

Authors: Aydin, Ahmet Levent | Sasani, Mehdi | Erbulut, Deniz Ufuk | Oktenoglu, Tunc | Ozer, Ali Fahir

Article Type: Research Article

Abstract: BACKGROUND: Laminectomy may cause kyphotic postoperative deformity in the cervical region leading to segmental instability over time. Laminoplasty may be an alternative procedure to laminectomy, as it protects the spine against post-laminectomy kyphosis; however, similar to laminectomy, laminoplasty may cause sagittal plane deformities by destructing or weakening the dorsal tension band. OBJECTIVE: Using finite element analysis (FE), we attempted to determine whether a posterior motion preservation system (PEEK posterior rod system concept) could overcome the postoperative complications of laminectomy and laminoplasty and eliminate the side effects of rigid posterior stabilization in the cervical region. METHODS: We …compared PEEK rods in four different diameters with a titanium rod for posterior cervical fixation. The present study may lead to motion preservation systems of the cervical vertebra. RESULTS: When PEEK rod is compared with titanium rod, considerable increase in range of motion is observed. CONCLUSIONS: PEEK rod-lateral mass screw instrumentation systems may be useful in motion preservation surgery of the posterior cervical region. Show more

Keywords: Laminoplasty, cervical dynamic instrumentation, non-fusion, cervical instrumentation, cervical disc disorders, PEEK rod system, posterior cervical fixation

DOI: 10.3233/BME-206004

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 4, pp. 235-251, 2020

Authors: Yang, Yujie | Zhang, Qianqian

Article Type: Research Article

Abstract: BACKGROUND: Pulmonary micronodules account for 80% of all lung nodules. Generally, pulmonary micronodules in the early stages can be detected on thoracic computed tomography (CT) scans. Early diagnosis is crucial for improving the patient’s survival rate. OBJECTIVE: This paper aims to estimate the malignancy risk of pulmonary micronodules and potentially improve the survival rate. METHODS: We extract 3D features of the CT images to obtain richer characteristics. Because superior performance can be achieved by having deep layers, we apply a 3D residual network (3D-ResNet) to classify the pulmonary micronodule. We construct a framework by using three …parallel ResNets whose inputs are CT images in different regions of interest, i.e., the multiview of the image. To further evaluate the applicability of the framework, we make a five-category classification and achieve good performance. RESULTS: By fusing different characteristics from three views, we achieve the area under the receiver operating characteristic curve (AUC) of 0.9681. Based on the results of the experiments, our 3D-ResNet has a better performance than 3D-VGG and 3D-Inception in terms of precision (the increase rates are 13.7% and 7.4%), AUC (the increase rates are 15.8% and 5.3%), and accuracy (the increase rates are 14.3% and 4.5%). Meanwhile, the recall performance is close to that of the 3D-Inception network. CONCLUSION: Overall, the framework we propose has applicability and feasibility in pulmonary micronodule classification. Show more

Keywords: Pulmonary micronodule, computed tomography (CT), multiview, three-dimensional residual network (3D-ResNet)

DOI: 10.3233/BME-206005

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 4, pp. 253-267, 2020