Rapid diagnosis of Salmonella is crucial for the effective control of food safety incidents, especially in regions with poor hygiene conditions. Polymerase chain reaction(PCR), as a promising tool for Salmonella detec...Rapid diagnosis of Salmonella is crucial for the effective control of food safety incidents, especially in regions with poor hygiene conditions. Polymerase chain reaction(PCR), as a promising tool for Salmonella detection, is facing a lack of simple and fast sensing methods that are compatible with field applications in resource-limited areas. In this work, we developed a sensing approach to identify PCR-amplified Salmonella genomic DNA with the naked eye in a snapshot. Based on the ratiometric fiuorescence signals from SYBR Green Ⅰ and Hydroxyl naphthol blue, positive samples stood out from negative ones with a distinct color pattern under UV exposure. The proposed sensing scheme enabled highly specific identification of Salmonella with a detection limit at the single-copy level. Also, as a supplement to the intuitive naked-eye visualization results, numerical analysis of the colored images was available with a smartphone app to extract RGB values from colored images. This work provides a simple, rapid, and user-friendly solution for PCR identification, which promises great potential in molecular diagnosis of Salmonella and other pathogens in field.展开更多
Fractional-N phase-locked loops(PLLs)are widely deployed in high-speed communication systems to generate local oscillator(LO)or clock signals with precise frequency.To support sophisticated modulations for increasing ...Fractional-N phase-locked loops(PLLs)are widely deployed in high-speed communication systems to generate local oscillator(LO)or clock signals with precise frequency.To support sophisticated modulations for increasing the data rate,the PLL needs to generate low-jitter output[1].展开更多
Towards a sustainable healthcare system,the clinicalgrade diagnostic platform should be decentralized into lowcost consumer-grade handheld devices,for broadly and early disease screening and diagnosis.The joint advanc...Towards a sustainable healthcare system,the clinicalgrade diagnostic platform should be decentralized into lowcost consumer-grade handheld devices,for broadly and early disease screening and diagnosis.The joint advancement of CMOS biosensors and signal-processing capability has recently transformed bulky laboratory instruments into handheld devices,leading to cost,size and weight reduction by orders of magnitude.This article gives a glimpse of the lab-on-CMOS in-vitro diagnostic(IVD)tools for point-of-care applications.展开更多
This paper explored the practical utility of gas sensing applications based on the multi-degree-of-freedom(Multi-DoF)bulk acoustic wave(BAW)resonant sensors,including 1,2,and 3-DoF devices,where piezoelectric actuatio...This paper explored the practical utility of gas sensing applications based on the multi-degree-of-freedom(Multi-DoF)bulk acoustic wave(BAW)resonant sensors,including 1,2,and 3-DoF devices,where piezoelectric actuation and sensing methods were adopted.Zeolitic imidazolate framework-8(ZIF-8)was chosen for the adsorption and desorption of the ethanol vapor,thereby facilitating the gas sensing mechanism and introducing the external mass changes to the multi-DoF resonating system.Similar to conventional quartz crystal microbalance(QCM)gas sensors,the frequency shift of all the devices(1,2,and 3-DoF devices)was tracked to characterize the sensitivity.Besides,for the 2 and 3-DoF devices,the amplitude ratio(AR)change was also recorded and observed with an enhancement in performance.Compared with the state-of-the-art gas sensor based on 2-DoFcapacitively coupled resonators,the presented devices achieved better Q factor in air,stability,and resolution in terms of both frequency shifts and AR changes.The dominant mass change(dominant stiffness change in the state-of-the-art)of the proposed resonant devices matched well with the theoretical mass sensing principle,which is both predictable and crucial for the accurate modeling of the practical mass sensor.Furthermore,a lower ethanol vapor concentration from 0.1%to 2%was successfully detected by the proposed 2-DoF device,demonstrating even better sensing performance than that of the state-of-the-art.展开更多
This paper describes a novel,system-level design methodology based on a genetic algorithm(GA)using freeform geometries for microelectromechanical systems(MEMS)devices.The proposed method can concurrently design and co...This paper describes a novel,system-level design methodology based on a genetic algorithm(GA)using freeform geometries for microelectromechanical systems(MEMS)devices.The proposed method can concurrently design and co-optimize the electronic and mechanical parts of a MEMS device comprising freeform geometries to achieve a better system performance,i.e.,a high sensitivity,a good system stability,and large fabrication tolerances.Also,the introduction of freeform geometries allows higher degrees of freedom in the design process,improving the diversity and potentially the performance of the MEMS devices.A MEMS accelerometer comprising a freeform mechanical motion preamplifier in a closed-loop control system is presented to demonstrate the effectiveness of the design approach.The optimization process shows the main figure-of-merit(FOM)is improved by 195%.In the mechanical component alone(open-loop system),the product of sensitivity and bandwidth has improved by 151%,with sensitivity increasing by 276%.For closed-loop performance,there is an improvement of 120%for the ratio of open and closed-loop displacements.The product of sensitivity and bandwidth is improved by 27%in the closed-loop system.Excellent immunities to fabrication errors and parameter mismatch are achieved.Experiments show that the displacement of the MEMS accelerometer in the closed-loop system decreased by 86%with 4.85 V feedback voltage compared with that in the open-loop system under a 1 g 100 Hz acceleration input.The static and dynamic nonlinearities in the closed-loop system are improved by 64%and 61%,respectively,compared with those in the open-loop system,in the±1 g acceleration input range.Besides,the closed-loop system improves the cross-axis sensitivity by 18.43%,compared with that in the open-loop system.It is the first time a closed-loop system for a MEMS accelerometer comprising a mechanical motion preamplifier is successfully implemented experimentally.展开更多
Despite the precise controllability of droplet samples in digital microfluidic(DMF)systems,their capability in isolating single cells for long-time culture is still limited:typically,only a few cells can be captured o...Despite the precise controllability of droplet samples in digital microfluidic(DMF)systems,their capability in isolating single cells for long-time culture is still limited:typically,only a few cells can be captured on an electrode.Although fabricating small-sized hydrophilic micropatches on an electrode aids single-cell capture,the actuation voltage for droplet transportation has to be significantly raised,resulting in a shorter lifetime for the DMF chip and a larger risk of damaging the cells.In this work,a DMF system with 3D microstructures engineered on-chip is proposed to form semi-closed micro-wells for efficient single-cell isolation and long-time culture.Our optimum results showed that approximately 20%of the micro-wells over a 30×30 array were occupied by isolated single cells.In addition,low-evaporation-temperature oil and surfactant aided the system in achieving a low droplet actuation voltage of 36V,which was 4 times lower than the typical 150 V,minimizing the potential damage to the cells in the droplets and to the DMF chip.To exemplify the technological advances,drug sensitivity tests were run in our DMF system to investigate the cell response of breast cancer cells(MDA-MB-231)and breast normal cells(MCF-10A)to a widely used chemotherapeutic drug,Cisplatin(Cis).The results on-chip were consistent with those screened in conventional 96-well plates.This novel,simple and robust single-cell trapping method has great potential in biological research at the single cell level.展开更多
This article overviews the design considerations and state-of-the-art of the ring voltage-controlled oscillator(VCO)-based phase-locked loops(PLLs)for clock generation in different applications.Partic-ularly,the objec...This article overviews the design considerations and state-of-the-art of the ring voltage-controlled oscillator(VCO)-based phase-locked loops(PLLs)for clock generation in different applications.Partic-ularly,the objective of the current work is to evaluate the required PLL performance among the fundamental metrics of power,jitter and area.An in-depth treatment of the mainstream PLL architectures and the associated design techniques enables them to be compared analyt-ically and benchmarked with respect to their figure-of-merit(FoM).The paper also summarizes the key concerns on the selection of dif-ferent circuit techniques to optimize the clock performance under dif-ferent scenarios.展开更多
基金supported by the Macao Science and Technology Development Fund(FDCT)(Nos.FDCT 0029/2021/A1,FDCT0002/2021/AKP,004/2023/SKL,0036/2021/APD)University of Macao(No.MYRG-GRG2023-00034-IME,SRG2024-00057IME)+2 种基金Dr.Stanley Ho Medical Development Foundation(No.SHMDF-OIRFS/2024/001)Zhuhai Huafa Group(No.HF-006-2021)Guangdong Science and Technology Department(No.2022A0505030022)。
文摘Rapid diagnosis of Salmonella is crucial for the effective control of food safety incidents, especially in regions with poor hygiene conditions. Polymerase chain reaction(PCR), as a promising tool for Salmonella detection, is facing a lack of simple and fast sensing methods that are compatible with field applications in resource-limited areas. In this work, we developed a sensing approach to identify PCR-amplified Salmonella genomic DNA with the naked eye in a snapshot. Based on the ratiometric fiuorescence signals from SYBR Green Ⅰ and Hydroxyl naphthol blue, positive samples stood out from negative ones with a distinct color pattern under UV exposure. The proposed sensing scheme enabled highly specific identification of Salmonella with a detection limit at the single-copy level. Also, as a supplement to the intuitive naked-eye visualization results, numerical analysis of the colored images was available with a smartphone app to extract RGB values from colored images. This work provides a simple, rapid, and user-friendly solution for PCR identification, which promises great potential in molecular diagnosis of Salmonella and other pathogens in field.
基金supported by the University of Macao Research Fund under Grant MYRG-GRG2024-00298-IMEby the Macao Science and Technology Development Fund(FDCT)under Grant 0103/2022/AFJ.
文摘Fractional-N phase-locked loops(PLLs)are widely deployed in high-speed communication systems to generate local oscillator(LO)or clock signals with precise frequency.To support sophisticated modulations for increasing the data rate,the PLL needs to generate low-jitter output[1].
文摘Towards a sustainable healthcare system,the clinicalgrade diagnostic platform should be decentralized into lowcost consumer-grade handheld devices,for broadly and early disease screening and diagnosis.The joint advancement of CMOS biosensors and signal-processing capability has recently transformed bulky laboratory instruments into handheld devices,leading to cost,size and weight reduction by orders of magnitude.This article gives a glimpse of the lab-on-CMOS in-vitro diagnostic(IVD)tools for point-of-care applications.
基金supported by The Science and Technology Development Fund,Macao SAR(FDCT),004/2023/SKLThe Science and Technology Development Fund,Macao SAR(FDCT),0087/2023/ITP2.
文摘This paper explored the practical utility of gas sensing applications based on the multi-degree-of-freedom(Multi-DoF)bulk acoustic wave(BAW)resonant sensors,including 1,2,and 3-DoF devices,where piezoelectric actuation and sensing methods were adopted.Zeolitic imidazolate framework-8(ZIF-8)was chosen for the adsorption and desorption of the ethanol vapor,thereby facilitating the gas sensing mechanism and introducing the external mass changes to the multi-DoF resonating system.Similar to conventional quartz crystal microbalance(QCM)gas sensors,the frequency shift of all the devices(1,2,and 3-DoF devices)was tracked to characterize the sensitivity.Besides,for the 2 and 3-DoF devices,the amplitude ratio(AR)change was also recorded and observed with an enhancement in performance.Compared with the state-of-the-art gas sensor based on 2-DoFcapacitively coupled resonators,the presented devices achieved better Q factor in air,stability,and resolution in terms of both frequency shifts and AR changes.The dominant mass change(dominant stiffness change in the state-of-the-art)of the proposed resonant devices matched well with the theoretical mass sensing principle,which is both predictable and crucial for the accurate modeling of the practical mass sensor.Furthermore,a lower ethanol vapor concentration from 0.1%to 2%was successfully detected by the proposed 2-DoF device,demonstrating even better sensing performance than that of the state-of-the-art.
基金supported by The Science and Technology Development Fund,Macao SAR(FDCT),004/2023/SKLThe Science and Technology Development Fund,Macao SAR(FDCT),0087/2023/ITP2.
文摘This paper describes a novel,system-level design methodology based on a genetic algorithm(GA)using freeform geometries for microelectromechanical systems(MEMS)devices.The proposed method can concurrently design and co-optimize the electronic and mechanical parts of a MEMS device comprising freeform geometries to achieve a better system performance,i.e.,a high sensitivity,a good system stability,and large fabrication tolerances.Also,the introduction of freeform geometries allows higher degrees of freedom in the design process,improving the diversity and potentially the performance of the MEMS devices.A MEMS accelerometer comprising a freeform mechanical motion preamplifier in a closed-loop control system is presented to demonstrate the effectiveness of the design approach.The optimization process shows the main figure-of-merit(FOM)is improved by 195%.In the mechanical component alone(open-loop system),the product of sensitivity and bandwidth has improved by 151%,with sensitivity increasing by 276%.For closed-loop performance,there is an improvement of 120%for the ratio of open and closed-loop displacements.The product of sensitivity and bandwidth is improved by 27%in the closed-loop system.Excellent immunities to fabrication errors and parameter mismatch are achieved.Experiments show that the displacement of the MEMS accelerometer in the closed-loop system decreased by 86%with 4.85 V feedback voltage compared with that in the open-loop system under a 1 g 100 Hz acceleration input.The static and dynamic nonlinearities in the closed-loop system are improved by 64%and 61%,respectively,compared with those in the open-loop system,in the±1 g acceleration input range.Besides,the closed-loop system improves the cross-axis sensitivity by 18.43%,compared with that in the open-loop system.It is the first time a closed-loop system for a MEMS accelerometer comprising a mechanical motion preamplifier is successfully implemented experimentally.
基金This work was supported by the FDCT110/2016/A3AMSV SKL Fund from the Macao Science and Technology Development Fund(FDCT)by MYRG2017-00022-AMSV and MYRG2018-00114-AMSV from the University of Macao.
文摘Despite the precise controllability of droplet samples in digital microfluidic(DMF)systems,their capability in isolating single cells for long-time culture is still limited:typically,only a few cells can be captured on an electrode.Although fabricating small-sized hydrophilic micropatches on an electrode aids single-cell capture,the actuation voltage for droplet transportation has to be significantly raised,resulting in a shorter lifetime for the DMF chip and a larger risk of damaging the cells.In this work,a DMF system with 3D microstructures engineered on-chip is proposed to form semi-closed micro-wells for efficient single-cell isolation and long-time culture.Our optimum results showed that approximately 20%of the micro-wells over a 30×30 array were occupied by isolated single cells.In addition,low-evaporation-temperature oil and surfactant aided the system in achieving a low droplet actuation voltage of 36V,which was 4 times lower than the typical 150 V,minimizing the potential damage to the cells in the droplets and to the DMF chip.To exemplify the technological advances,drug sensitivity tests were run in our DMF system to investigate the cell response of breast cancer cells(MDA-MB-231)and breast normal cells(MCF-10A)to a widely used chemotherapeutic drug,Cisplatin(Cis).The results on-chip were consistent with those screened in conventional 96-well plates.This novel,simple and robust single-cell trapping method has great potential in biological research at the single cell level.
基金supported by the National Natural Science Foundation of China under Grant 62004028,62090041the Science Foundation of Sichuan under Grant 2022NSFSC0927.
文摘This article overviews the design considerations and state-of-the-art of the ring voltage-controlled oscillator(VCO)-based phase-locked loops(PLLs)for clock generation in different applications.Partic-ularly,the objective of the current work is to evaluate the required PLL performance among the fundamental metrics of power,jitter and area.An in-depth treatment of the mainstream PLL architectures and the associated design techniques enables them to be compared analyt-ically and benchmarked with respect to their figure-of-merit(FoM).The paper also summarizes the key concerns on the selection of dif-ferent circuit techniques to optimize the clock performance under dif-ferent scenarios.
