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Objective: To propose a method for making organ-on-a-chip based on 3D printing, and study the relationship between cell growth on the chips and various factors. Methods: Through 3D printing technology and surface microstructure transfer method, ulcer-like and ridge-like mi-crostructures of the tumor surface and the intestinal villi were fabricated on a polydimethylsiloxane (PDMS) chip. Combined with fluorescence imaging, the effects of surface modification, shapes and heights of microstructures, and culture time on the surface coverage and density of Caco-2 cells on the chip were measured. Results:The PDMS chip was more likely to induce cell adhesion and growth rather than the 3D printing resin chip. On the surface of three-dimensional structure, cell surface coverage and cell density increased after the surface was treated with rat tail collagen (P0.05). Conclusion: The intestinal villi and tumor topological organ chips can be fabricated by 3D printing technology and surface microstructure transfer method. The surface modification and microstructure height affect the cell growth on the surface.
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Aims: Design and assembly of an inexpensive microfluidic PDMS chip for visual detection of cell adhesion and biofilm formation. Study Design: Three different styles of microchannels (2.6, 5.0, and 11.5 µl volumes) were designed, fabricated and tested for adhesion and biofilm formation in a microfluidic system. The pressure drop measurements system includes a bio-Ferrograph connected to the PDMS microchannel via a syringe and a pressure transducer. Methodology: Microfluidic chips were fabricated using Polydimethylsiloxane (PDMS) by means of soft lithography. Different cell densities of E.coli K12 cells were introduced to investigate adhesion and biofilm formation at different time intervals. Stabilization time and hydraulic resistance were obtained via a Bio-Ferrograph connected to a pressure transducer. Results: PDMS microfluidic volume (2.6 µl) failed to generate noticeable biofilm, while slight and greatest yield occurred with PDMS microchannels (5.0, and 11.5 µl), respectively, and could detect as low as 26 cells in 11.5 µl microchannel. As incubation time and/or initial cell density increases, cell adhesion increased, illustrated by crystal violet color intensity. High stabilization time (3 h) didn’t allow for bacterial attachment and cultivation inside the microchannel (2.6 µl) while lower stabilization time (10 min) yielded the highest capacity of cell adhesion in microchannel (11.5 µl). Conclusions: We developed a microfluidic chip with low stabilization time and hydraulic resistance, thus offering more volume for adhesion of bacterial cells and biofilm formation. It allowed bacterial cultivation without any addition of nutrients. The microfluidic chip provides a platform to monitor biofilm growth and can be integrated in situ investigations for biological systems, food biotechnology and other industrial biotechnology applications. This would allow a non-destructive and non-invasive monitoring of the biofilm-forming bacteria inside the PDMS microfluidic chip. This work opens opportunities for further investigations of pressure drop phenomena in microchannels that would otherwise go unnoticed in macro scale measurements.
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This paper addresses the modification of poly(dimethylsiloxane), i.e. PDMS, using plasma surface treatment and a novel application of the membrane created. A set of model compounds were analysed to determine their permeation through PDMS, both with and without plasma treatment. It was found that plasma treatment reduced permeation for the majority of compounds but had little effect on some compounds, such as caffeine, with results indicating that polarity plays an important role in permeation, as is seen in human skin. Most importantly, a direct correlation was observed between plasma-modified permeation data and literature data through calculation of membrane permeability (Kp) values suggesting plasma-modified silicone membrane (PMSM) could be considered as a suitable in vivo replacement to predict clinical skin permeation.
ABSTRACT
This paper addresses the modification of poly(dimethylsiloxane), i.e. PDMS, using plasma surface treatment and a novel application of the membrane created. A set of model compounds were analysed to determine their permeation through PDMS, both with and without plasma treatment. It was found that plasma treatment reduced permeation for the majority of compounds but had little effect on some compounds, such as caffeine, with results indicating that polarity plays an important role in permeation, as is seen in human skin. Most importantly, a direct correlation was observed between plasma-modified permeation data and literature data through calculation of membrane permeability (Kp) values suggesting plasma-modified silicone membrane (PMSM) could be considered as a suitable in vivo replacement to predict clinical skin permeation.
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A review of cell traction forces (CTFs) measurement based on Biological MiCro Electromechanical Systems (BioMEMS) microposts matrix is presented.CTFs are exerted by cells and ansmitted to the underly-ing substrate through focal adhesions and close contacts.which is essential for cells movement.Cells probe the mechanicaI compliance of the exlracellular mabix (ECM) in part by locally deforming it with nanonewton-scale traction forces.Precision measurement of CTFs is significant for many researches such as call biology and tissue engineering and so on.Enabled by the advancement in BioMEMS technology,surface treated high aspeect ratio Polydimethyisiloxane(PDMS)micropos matrix devices,which serve as BioMEMS sensom for de-tecting cellular nanoforces and studying in vitro cell mechanics,have been developed.Closely spaced vartical microposts matrixes were designed to encourage cells to attach and spread across multiple microposts,and to bend the microposts like vertical cantilevers as the cells locomote on the surface.Using this dense and dis-crete matrix of microposts rather than a convanfional continuous substrate,CTFs can be directly measured and quantified by processing the microscopy images of the deformations of microposts.The resolution of the force was in tens of nN/μm scale.At first,the conventional CTFs measurement methods were concisely summa-rized.Then BioMEMS microposts matrix method was described in detail,including principle and fabfication process,Surface treatment and cell expedment results.Furthermore,high aspect ratio structure collapse prob-lem was investigated.
ABSTRACT
A review of cell traction forces (CTFs) measurement based on Biological MiCro Electromechanical Systems (BioMEMS) microposts matrix is presented.CTFs are exerted by cells and ansmitted to the underly-ing substrate through focal adhesions and close contacts.which is essential for cells movement.Cells probe the mechanicaI compliance of the exlracellular mabix (ECM) in part by locally deforming it with nanonewton-scale traction forces.Precision measurement of CTFs is significant for many researches such as call biology and tissue engineering and so on.Enabled by the advancement in BioMEMS technology,surface treated high aspeect ratio Polydimethyisiloxane(PDMS)micropos matrix devices,which serve as BioMEMS sensom for de-tecting cellular nanoforces and studying in vitro cell mechanics,have been developed.Closely spaced vartical microposts matrixes were designed to encourage cells to attach and spread across multiple microposts,and to bend the microposts like vertical cantilevers as the cells locomote on the surface.Using this dense and dis-crete matrix of microposts rather than a convanfional continuous substrate,CTFs can be directly measured and quantified by processing the microscopy images of the deformations of microposts.The resolution of the force was in tens of nN/μm scale.At first,the conventional CTFs measurement methods were concisely summa-rized.Then BioMEMS microposts matrix method was described in detail,including principle and fabfication process,Surface treatment and cell expedment results.Furthermore,high aspect ratio structure collapse prob-lem was investigated.
ABSTRACT
A review of cell traction forces (CTFs) measurement based on Biological MiCro Electromechanical Systems (BioMEMS) microposts matrix is presented.CTFs are exerted by cells and ansmitted to the underly-ing substrate through focal adhesions and close contacts.which is essential for cells movement.Cells probe the mechanicaI compliance of the exlracellular mabix (ECM) in part by locally deforming it with nanonewton-scale traction forces.Precision measurement of CTFs is significant for many researches such as call biology and tissue engineering and so on.Enabled by the advancement in BioMEMS technology,surface treated high aspeect ratio Polydimethyisiloxane(PDMS)micropos matrix devices,which serve as BioMEMS sensom for de-tecting cellular nanoforces and studying in vitro cell mechanics,have been developed.Closely spaced vartical microposts matrixes were designed to encourage cells to attach and spread across multiple microposts,and to bend the microposts like vertical cantilevers as the cells locomote on the surface.Using this dense and dis-crete matrix of microposts rather than a convanfional continuous substrate,CTFs can be directly measured and quantified by processing the microscopy images of the deformations of microposts.The resolution of the force was in tens of nN/μm scale.At first,the conventional CTFs measurement methods were concisely summa-rized.Then BioMEMS microposts matrix method was described in detail,including principle and fabfication process,Surface treatment and cell expedment results.Furthermore,high aspect ratio structure collapse prob-lem was investigated.
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@#ObjectiveTo investigate the efficacy of acupuncture point injection for fine motor functions in children with cerebral palsy.Methods57 children with cerebral palsy were treated by acupuncture point injection combined with occupational therapy. The efficacy was evaluated by the Peabody Developmental Motor Scale-Fine Motor (PDMS-FM).ResultsThe fine motor quotient (FMQ) of 34 children (59.7%) elevated. The raw scores of grasping subtest (Gr) elevated in 45 children (78.9%) and the raw scores of visual-motor integration (VI) elevated in 53 children (93.0%).ConclusionThe efficacy of acupuncture point injection combined with occupational therapy is significant in children with cerebral palsy.
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@#Objective To compare the advantages of two gross motor measure scales, Peabody Developmental Measure Scale Gross Motor (PDMS-GM) and Gross Motor Function Measure Scale (GMFM), in the evaluation of children with cerebral palsy (CP).Methods The gross motor functions of 29 CP children, 0-3 years old, were evaluated three times using PDMS-GM and GMFM respectively. The improvement percentile each month of PDMS-GM and GMFM were compared by t test.Results There was significant difference between the improvement percentile each month of PDMS-GM and GMFM. Conclusion The GMFM was more sensitive than PDMS-GM in the evaluation of CP children especially in the evaluation of treatment effect.
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Objective To define whether correlation exists between the enlargement of lateral ventricles and motor development delay. Methods Motor development was assessed with Peabody Developmental Motor Scale (PDMS) in 28 children with cerebral palsy. Correlation between computerized tomography (CT) findings of enlargement of lateral ventricles (ventricle index,body index,width index and frontal horn index) and motor quotients of PDMS(GMQ,FMQ and TMQ) was analyzed. Results Width index was correlated with all three motor quotients (GMQ,FMQ and TMQ)( P
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@# ObjectiveTo investigat e the improvement of fine motor functions after occupational therapy in children w ith cerebral palsy (CP) and mental retardation (MR), and also using the value of Peabody developmental motor scale-fine motor (PDMS-FM) to evaluate their fine motor functions.MethodsAll children have received occupational therapy (OT) for three months. Their fine motor functions before an d after OT were observed and evaluated using PDMS-FM by the therapist.ResultsAll children have their fine motor functions obvious ly improved after OT. Results of PDMS-FM test indicated that fine motor functio ns between CP and MR group were comparable before and after OT, the MR group hav e their fine motor functions significantly improved after OT (P<0.001 ),although the CP group also have their fine motor functions impr oved after OT, there wasn't significant difference (P>0.05).Conclusions Fine motor functions of CP and MR children could be improved after OT. PDMS-FM was suitable to evaluate fine mot or function changes, especially in children with MR.