BioMedical Engineering OnLine. Feb 18, 2020, Vol. 19 Issue 1
Infection -- Health aspects, Antibacterial agents -- Health aspects, and Hydrochloric acid -- Health aspects
Author(s): Rui Ma[sup.1] , Wei Wang[sup.1] , Pei Yang[sup.1] , Chunsheng Wang[sup.1] , Dagang Guo[sup.2] and Kunzheng Wang[sup.1] Background Bone defects are often at a high risk for infection due [...] Background Bone defects are often combined with the risk of infection in the clinic, and artificial bone substitutes are often implanted to repair the defective bone. However, the implant materials are carriers for bacterial growth, and biofilm can form on the implant surface, which is difficult to eliminate using antibiotics and the host immune system. Magnesium (Mg) was previously reported to possess antibacterial potential. Methods In this study, Mg was incorporated into poly(lactide-co-glycolic acid) (PLGA) to fabricate a PLGA/Mg scaffold using a low-temperature rapid-prototyping technique. All scaffolds were divided into three groups: PLGA (P), PLGA/10 wt% Mg with low Mg content (PM-L) and PLGA/20 wt% Mg with high Mg content (PM-H). The degradation test of the scaffolds was conducted by immersing them into the trihydroxymethyl aminomethane-hydrochloric acid (Tris-HCl) buffer solution and measuring the change of pH values and concentrations of Mg ions. The antibacterial activity of the scaffolds was investigated by the spread plate method, tissue culture plate method, scanning electron microscopy and confocal laser scanning microscopy. Additionally, the cell attachment and proliferation of the scaffolds were evaluated by the cell counting kit-8 (CCK-8) assay using MC3T3-E1 cells. Results The Mg-incorporated scaffolds degraded and released Mg ions and caused an increase in the pH value. Both PM-L and PM-H inhibited bacterial growth and biofilm formation, and PM-H exhibited higher antibacterial activity than PM-L after incubation for 24 and 48 h. Cell tests revealed that PM-H exerted a suppressive effect on cell attachment and proliferation. Conclusions These findings demonstrated that the PLGA/Mg scaffolds possessed favorable antibacterial activity, and a higher content of Mg (20%) exhibited higher antibacterial activity and inhibitory effects on cell attachment and proliferation than low Mg content (10%). Keywords: Magnesium, Antibacterial activity, Poly(lactide-co-glycolic acid), Infection, Scaffold
Abd Razak, Nasrul Anuar, Abu Osman, Noor Azuan, Gholizadeh, Hossein, and Ali, Sadeeq
BioMedical Engineering OnLine. April 23, 2014, Vol. 13 Issue 1
Computer-aided design -- Analysis
Author(s): Nasrul Anuar Abd Razak[sup.1], Noor Azuan Abu Osman[sup.1], Hossein Gholizadeh[sup.1] and Sadeeq Ali[sup.1] Background Functional prosthetic hands can be classified into two parts; body powered prosthesis (uses tension cable) [...] Background The design and performance of a new development prosthesis system known as biomechatronics wrist prosthesis is presented in this paper. The prosthesis system was implemented by replacing the Bowden tension cable of body powered prosthesis system using two ultrasonic sensors, two servo motors and microcontroller inside the prosthesis hand for transradial user. Methods The system components and hand prototypes involve the anthropometry, CAD design and prototyping, biomechatronics engineering together with the prosthetics. The modeler construction of the system develop allows the ultrasonic sensors that are placed on the shoulder to generate the wrist movement of the prosthesis. The kinematics of wrist movement, which are the pronation/supination and flexion/extension were tested using the motion analysis and general motion of human hand were compared. The study also evaluated the require degree of detection for the input of the ultrasonic sensor to generate the wrist movements. Results The values collected by the vicon motion analysis for biomechatronics prosthesis system were reliable to do the common tasks in daily life. The degree of the head needed to bend to give the full input wave was about 45[degrees] - 55[degrees] of rotation or about 14 cm - 16 cm. The biomechatronics wrist prosthesis gave higher degree of rotation to do the daily tasks but did not achieve the maximum degree of rotation. Conclusion The new development of using sensor and actuator in generating the wrist movements will be interesting for used list in medicine, robotics technology, rehabilitations, prosthetics and orthotics. Keywords: Anthropometrics in designing prosthesis, Biomechatronics in prosthesis, Motion analysis, Transradial prosthetics
Pagnano, Rodrigo G., Okubo, Rodrigo, and Volpon, Jose B.
BioMedical Engineering OnLine. June 28, 2011, Vol. 10, 57
Bone diseases -- Care and treatment, Bone diseases -- Research, Bone diseases -- Risk factors, Cerebral palsy -- Diagnosis, Cerebral palsy -- Research, and Osteotomy -- Health aspects
Authors: Rodrigo G Pagnano (corresponding author) ; Rodrigo Okubo ; Jose B Volpon  Background Femoral anteversion is the anterior projection of the femoral neck related to the coronal plane. [...] Background Rotational osteotomy is frequently indicated to correct excessive femoral anteversion in cerebral palsy patients. Angled blade plate is the standard fixation device used when performed in the proximal femur, but extensile exposure is required for plate accommodation. The authors developed a short locked intramedullary nail to be applied percutaneously in the fixation of femoral rotational osteotomies in children with cerebral palsy and evaluated its mechanical properties. Methods The study was divided into three stages. In the first part, a prototype was designed and made based on radiographic measurements of the femoral medullary canal of ten-year-old patients. In the second, synthetic femoral models based on rapid-prototyping of 3D reconstructed images of patients with cerebral palsy were obtained and were employed to adjust the nail prototype to the morphological changes observed in this disease. In the third, rotational osteotomies were simulated using synthetic femoral models stabilized by the nail and by the AO-ASIF fixed-angle blade plate. Mechanical testing was done comparing both devices in bending-compression and torsion. Results The authors observed proper adaptation of the nail to normal and morphologically altered femoral models, and during the simulated osteotomies. Stiffness in bending-compression was significantly higher in the group fixed by the plate (388.97 [+ -] 57.25 N/mm) than in that fixed by the nail (268.26 [+ -] 38.51 N/mm) as torsional relative stiffness was significantly higher in the group fixed by the plate (1.07 [+ -] 0.36 Nm/[degrees]) than by the nail (0.35 [+ -] 0.13 Nm/[degrees]). Conclusions Although the device presented adequate design and dimension to fit into the pediatric femur, mechanical tests indicated that the nail was less stable than the blade plate in bending-compression and torsion. This may be a beneficial property, and it can be attributed to the more flexible fixation found in intramedullary devices.