Gravimetric resonant-inspired biosensors have attracted increasing attention in industrial and point-ofcare applications,enabling label-free detection of biomarkers such as DNA and antibodies.Capacitive micromachined ...Gravimetric resonant-inspired biosensors have attracted increasing attention in industrial and point-ofcare applications,enabling label-free detection of biomarkers such as DNA and antibodies.Capacitive micromachined ultrasonic transducers(CMUTs)are promising tools for developing miniaturized highperformance biosensing complementary metal–oxide–silicon(CMOS)platforms.However,their operability is limited by inefficient functionalization,aggregation,crosstalk in the buffer,and the requirement for an external high-voltage(HV)power supply.In this study,we aimed to propose a CMUTs-based resonant biosensor integrated with a CMOS front–end interface coupled with ethylene–glycol alkanethiols to detect single-stranded DNA oligonucleotides with large specificity.The topography of the functionalized surface was characterized by energy-dispersive X-ray microanalysis.Improved selectivity for onchip hybridization was demonstrated by comparing complementary and non-complementary singlestranded DNA oligonucleotides using fluorescence imaging technology.The sensor array was further characterized using a five-element lumped equivalent model.The 4 mm^(2) application-specific integrated circuit chip was designed and developed through 0.18 lm HV bipolar-CMOS-double diffused metal–oxide–silicon(DMOS)technology(BCD)to generate on-chip 20 V HV boosting and to track feedback frequency under a standard 1.8 V supply,with a total power consumption of 3.8 mW in a continuous mode.The measured results indicated a detection sensitivity of 7.943×10^(-3) lmol·L^(-1)·Hz^(-1) over a concentration range of 1 to 100 lmol·L^(-1).In conclusion,the label-free biosensing of DNA under dry conditions was successfully demonstrated using a microfabricated CMUT array with a 2 MHz frequency on CMOS electronics with an internal HV supplier.Moreover,ethylene–glycol alkanethiols successfully deposited self-assembled monolayers on aluminum electrodes,which has never been attempted thus far on CMUTs,to enhance the selectivity of bio-functionalization.The findings of this study indicate the possibility of full-on-chip DNA biosensing with CMUTs.展开更多
The B3LYP/LanL1MB and B3LYP/LanL2DZ methods for Ag atom in conjunction with the 6-31G（d） basis set for S, C and H atoms were used to optimize the geometries and calculate the energies for （SCH3）mAg20 （re=1-4）, r...The B3LYP/LanL1MB and B3LYP/LanL2DZ methods for Ag atom in conjunction with the 6-31G（d） basis set for S, C and H atoms were used to optimize the geometries and calculate the energies for （SCH3）mAg20 （re=1-4）, respectively. A single molecular adsorption energy of （SCH3）m （rn=1-4） on Ag20 and the intermolecular substrate-mediated interaction energy were evaluated. The results revealed that there is a proportional relation between the single molecular adsorption energy and the substrate-mediated intermolecular interaction energy. The results qualitatively demonstrated the semi-empirical expression for the substratemediated interaction energy proposed previously by us is consistent with the results of the density functional theory.展开更多
The structures of self-assembled monolayers(SAMs)of short(methyl)and long(hexyl)chain alkyl thiols on the clean gold(111)surface were modeled using for the Au–S interactions either the reactive ReaxFF potential or th...The structures of self-assembled monolayers(SAMs)of short(methyl)and long(hexyl)chain alkyl thiols on the clean gold(111)surface were modeled using for the Au–S interactions either the reactive ReaxFF potential or the well-known nonreactive Morse potential,while for the Au–Au interactions either the ReaxFF potential or an embeddedatom method(EAM).Analysis of the molecular dynamics(MD)trajectories of possible SAM structures suggests that disordering of interfacial Au atoms is definitely driven by the gold–sulphur interactions.Our MD results reveal a novel structure where two methanethiol molecules are bound to a gold adatom that has been lifted from the surface at 300 K,and the same kind of RS–Au–SR motif was also observed for hexanethiol at 600 K but not at 300 K.What is more,the above motif is only observed for the reactive ReaxFF potential.Moreover,these results are in clear agreement with recent experiments and more costly first principles-based MD simulations.These findings strongly support the use of reactive potentials such as ReaxFF for gathering an accurate description of Au–S interactions in inexpensive classical MD simulations.展开更多
Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly....Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly. It introduces the progresses on molecular self-assembly of alkanethiols in detail.展开更多
Restrained molecular dynamics simulations were performed to study the binding affinity of the peptide with alkanethiols of different tail-groups, S（CH2）7CH3, S（CH2）7OH and S（CH2）7COOH, which self-assembled on Au...Restrained molecular dynamics simulations were performed to study the binding affinity of the peptide with alkanethiols of different tail-groups, S（CH2）7CH3, S（CH2）7OH and S（CH2）7COOH, which self-assembled on Au（111） surface in the presence of water molecules. The curves of binding affinity were calculated by fixing the center of mass of the peptide at various distances from the assembling surface. Simulation results show that the binding affin- ity is in the order as COOH-SAMs〉OH-SAMs〉CH3-SAMs, while 100% COOH-SAMs〉5% COOH-SAMS in concentration. The effects on binding affinity by different tail-groups were also studied. Results show that the binding affinity between COOH-SAMs and the peptide is bigger than those of the others and increasing the acidity of COOH-SAMs will result in stronger attractive power.展开更多
基金supported by the National Key Research and Development Program of China(2022YFB3205400)the National Natural Science Foundation of China(52275570)+1 种基金the Postdoctoral Innovation Talents Support Program(BX20230288)the Postdoctoral Science Foundation of Shaanxi Province(2018BSHEDZZ08).
文摘Gravimetric resonant-inspired biosensors have attracted increasing attention in industrial and point-ofcare applications,enabling label-free detection of biomarkers such as DNA and antibodies.Capacitive micromachined ultrasonic transducers(CMUTs)are promising tools for developing miniaturized highperformance biosensing complementary metal–oxide–silicon(CMOS)platforms.However,their operability is limited by inefficient functionalization,aggregation,crosstalk in the buffer,and the requirement for an external high-voltage(HV)power supply.In this study,we aimed to propose a CMUTs-based resonant biosensor integrated with a CMOS front–end interface coupled with ethylene–glycol alkanethiols to detect single-stranded DNA oligonucleotides with large specificity.The topography of the functionalized surface was characterized by energy-dispersive X-ray microanalysis.Improved selectivity for onchip hybridization was demonstrated by comparing complementary and non-complementary singlestranded DNA oligonucleotides using fluorescence imaging technology.The sensor array was further characterized using a five-element lumped equivalent model.The 4 mm^(2) application-specific integrated circuit chip was designed and developed through 0.18 lm HV bipolar-CMOS-double diffused metal–oxide–silicon(DMOS)technology(BCD)to generate on-chip 20 V HV boosting and to track feedback frequency under a standard 1.8 V supply,with a total power consumption of 3.8 mW in a continuous mode.The measured results indicated a detection sensitivity of 7.943×10^(-3) lmol·L^(-1)·Hz^(-1) over a concentration range of 1 to 100 lmol·L^(-1).In conclusion,the label-free biosensing of DNA under dry conditions was successfully demonstrated using a microfabricated CMUT array with a 2 MHz frequency on CMOS electronics with an internal HV supplier.Moreover,ethylene–glycol alkanethiols successfully deposited self-assembled monolayers on aluminum electrodes,which has never been attempted thus far on CMUTs,to enhance the selectivity of bio-functionalization.The findings of this study indicate the possibility of full-on-chip DNA biosensing with CMUTs.
基金Ⅴ. ACKN0WLEDGMENTSThis work was supported by the National Natural Science Foundation of China （No.20473078） and The Ph.D. Programs Foundation of Ministry of Education of China （No.20020358061）.
文摘The B3LYP/LanL1MB and B3LYP/LanL2DZ methods for Ag atom in conjunction with the 6-31G（d） basis set for S, C and H atoms were used to optimize the geometries and calculate the energies for （SCH3）mAg20 （re=1-4）, respectively. A single molecular adsorption energy of （SCH3）m （rn=1-4） on Ag20 and the intermolecular substrate-mediated interaction energy were evaluated. The results revealed that there is a proportional relation between the single molecular adsorption energy and the substrate-mediated intermolecular interaction energy. The results qualitatively demonstrated the semi-empirical expression for the substratemediated interaction energy proposed previously by us is consistent with the results of the density functional theory.
基金supported by Project PTDC/CTMNAN/112241/2009Grant No.Pest−C/EQB/LA0006/2011+2 种基金financed by FEDER through COMPETE-Programa Operacional Factores de CompetitividadeFCT-Funda¸cão para a Ciência e a Tecnologia.J.L.C.Fajin acknowledges FCT for the grant SFRH/BPD/64566/2009 cofinancedthe Fundo Social Europen(FSE).
文摘The structures of self-assembled monolayers(SAMs)of short(methyl)and long(hexyl)chain alkyl thiols on the clean gold(111)surface were modeled using for the Au–S interactions either the reactive ReaxFF potential or the well-known nonreactive Morse potential,while for the Au–Au interactions either the ReaxFF potential or an embeddedatom method(EAM).Analysis of the molecular dynamics(MD)trajectories of possible SAM structures suggests that disordering of interfacial Au atoms is definitely driven by the gold–sulphur interactions.Our MD results reveal a novel structure where two methanethiol molecules are bound to a gold adatom that has been lifted from the surface at 300 K,and the same kind of RS–Au–SR motif was also observed for hexanethiol at 600 K but not at 300 K.What is more,the above motif is only observed for the reactive ReaxFF potential.Moreover,these results are in clear agreement with recent experiments and more costly first principles-based MD simulations.These findings strongly support the use of reactive potentials such as ReaxFF for gathering an accurate description of Au–S interactions in inexpensive classical MD simulations.
文摘Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly. It introduces the progresses on molecular self-assembly of alkanethiols in detail.
文摘Restrained molecular dynamics simulations were performed to study the binding affinity of the peptide with alkanethiols of different tail-groups, S（CH2）7CH3, S（CH2）7OH and S（CH2）7COOH, which self-assembled on Au（111） surface in the presence of water molecules. The curves of binding affinity were calculated by fixing the center of mass of the peptide at various distances from the assembling surface. Simulation results show that the binding affin- ity is in the order as COOH-SAMs〉OH-SAMs〉CH3-SAMs, while 100% COOH-SAMs〉5% COOH-SAMS in concentration. The effects on binding affinity by different tail-groups were also studied. Results show that the binding affinity between COOH-SAMs and the peptide is bigger than those of the others and increasing the acidity of COOH-SAMs will result in stronger attractive power.
