Lancet needle, having three planes at the tip to generate a sharp lancet point, is the most common needle tip geometry and used for medical procedures. This research presents two five-plane lancet needle designs, the ...Lancet needle, having three planes at the tip to generate a sharp lancet point, is the most common needle tip geometry and used for medical procedures. This research presents two five-plane lancet needle designs, the five-plane lancet needle with two back bevels （FLN-B） and five-plane lancet needle with two front bevels （FLN-F）, to study the effects of two additional bevel planes on the reduction of soft tissue cutting force. Mathematical models to calculate the inclination angle and rake angle along the cutting edges of FLN-B and FLN-F are developed. By using the grinding process, the prototype FLN-B and FLN-F needles are fabricated. And their inclination and rake angles along the cutting edges are investigated and compared to that of regular lancet needle. Needles insertion tests were conducted on soft PVC phantom which mimics the soft tissue. The initial peak insertion force and steady-state cutting force during needle insertion were identified, and the effect of cutting edge on needle soft tissue cutting force was studied. Compared to lancet needle, FLN-B and FLN-F both have higher inclination and rake angles at the tip cutting edge, could reduce the initial peak needle insertion force and tissue cutting forces, and thus can efficiently cut the soft tissue for medical applications.展开更多
Compared with stiff silicon-based probes,flexible neural probes can alleviate biological inflammation and tissue rejection.A polyethylene glycol(PEG)coating can facilitate the insertion of flexible probes,and the fabr...Compared with stiff silicon-based probes,flexible neural probes can alleviate biological inflammation and tissue rejection.A polyethylene glycol(PEG)coating can facilitate the insertion of flexible probes,and the fabrication methods have a significant impact on the dimensional accuracy and structural strength of the coating.In this study,a novel melting injection moulding method is used to process a PEG-dexamethasone(PEG-DEX)coating with high structural strength for a type of mesh-shaped photosensitive polyimide(PSPI)based neural probe.Combined with the digital image correlation(DIC)method,an in vitro test system with high accuracy is developed to evaluate the effects of the elastic modulus of the PEG component and two fabrication methods,i.e.,computer-numerical-control(CNC)micro-milling and laser engraving,on the processing quality and implantation mechanics of a PEG-DEX coated probe.The results show that compared with laser engraving,CNC micro-milling can ensure high dimensional accuracy and sharpness for the composite coating,thus leading to small damage from implantation,whereas the elastic modulus of the composite coating has a limited effect on the implantation mechanics of the PEG-DEX coated probe.展开更多
文摘Lancet needle, having three planes at the tip to generate a sharp lancet point, is the most common needle tip geometry and used for medical procedures. This research presents two five-plane lancet needle designs, the five-plane lancet needle with two back bevels （FLN-B） and five-plane lancet needle with two front bevels （FLN-F）, to study the effects of two additional bevel planes on the reduction of soft tissue cutting force. Mathematical models to calculate the inclination angle and rake angle along the cutting edges of FLN-B and FLN-F are developed. By using the grinding process, the prototype FLN-B and FLN-F needles are fabricated. And their inclination and rake angles along the cutting edges are investigated and compared to that of regular lancet needle. Needles insertion tests were conducted on soft PVC phantom which mimics the soft tissue. The initial peak insertion force and steady-state cutting force during needle insertion were identified, and the effect of cutting edge on needle soft tissue cutting force was studied. Compared to lancet needle, FLN-B and FLN-F both have higher inclination and rake angles at the tip cutting edge, could reduce the initial peak needle insertion force and tissue cutting forces, and thus can efficiently cut the soft tissue for medical applications.
基金the National Natural Science Foundation of China(No.51675330)。
文摘Compared with stiff silicon-based probes,flexible neural probes can alleviate biological inflammation and tissue rejection.A polyethylene glycol(PEG)coating can facilitate the insertion of flexible probes,and the fabrication methods have a significant impact on the dimensional accuracy and structural strength of the coating.In this study,a novel melting injection moulding method is used to process a PEG-dexamethasone(PEG-DEX)coating with high structural strength for a type of mesh-shaped photosensitive polyimide(PSPI)based neural probe.Combined with the digital image correlation(DIC)method,an in vitro test system with high accuracy is developed to evaluate the effects of the elastic modulus of the PEG component and two fabrication methods,i.e.,computer-numerical-control(CNC)micro-milling and laser engraving,on the processing quality and implantation mechanics of a PEG-DEX coated probe.The results show that compared with laser engraving,CNC micro-milling can ensure high dimensional accuracy and sharpness for the composite coating,thus leading to small damage from implantation,whereas the elastic modulus of the composite coating has a limited effect on the implantation mechanics of the PEG-DEX coated probe.
