A novel immunosensor based on surface plasmon resonance（SPR） has been developed for the recognition of antigen. The sensor was designed on the basis of the fixed angle of incidence and measuring the reflected intens...A novel immunosensor based on surface plasmon resonance（SPR） has been developed for the recognition of antigen. The sensor was designed on the basis of the fixed angle of incidence and measuring the reflected intensities in a wavelength range of 430--750 nm in real-time. An ultra-bright white light-emitting diode（LED） was used as the light source. Molecular self-assembling in solution was used to form the sensing membrane on gold substrate. It has been seen that the sensitivity of the SPR sensor with 3-mercaptopropionic acid（MPA）/protein A（SPA） sensing membrane is considerably higher than that with MPA or SPA modified sensing membrane. The kinetic processes on the sensing membrane were studied. The human B factor（Bf）, an activator of complement 3（C3）, was recognized among the other antigens. This sensor can also be used for other antigen/antibody or adaptor/receptor recognition. Under optimized experimental conditions, the sensor has good selectivity, repeatability, and reversibility.展开更多
Plasmonic enhanced fluorescence(PEF)technology is a powerful strategy to improve the sensitivity of immunofluorescence microarrays(IFMA),however,current approaches to constructing PEF platforms are either expensive/ti...Plasmonic enhanced fluorescence(PEF)technology is a powerful strategy to improve the sensitivity of immunofluorescence microarrays(IFMA),however,current approaches to constructing PEF platforms are either expensive/time-consuming or reliant on specialized instruments.Here,we develop a completely alternative approach relying on a two-step protocol that includes the self-assembly of gold nanoparticles(GNPs)at the water–oil interface and subsequent annealing-assisted regulation of gold nanogap.Our optimized thermal-annealing GNPs(TA-GNP)platform generates adequate hot spots,and thus produces high-density electromagnetic coupling,eventually enabling 240-fold fluorescence enhancement of probed dyes in the near-infrared region.For clinical detection of human samples,TA-GNP provides super-high sensitivity and low detection limits for both hepatitis B surface antigen and SARS-CoV-2 binding antibody,coupled with a much-improved detection dynamic range up to six orders of magnitude.With fast detection,high sensitivity,and low detection limit,TA-GNP could not only substantially improve the outcomes of IFMA-based precision medicine but also find applications in fields of proteomic research and clinical pathology.展开更多
Severe acute respiratory syndrome-associated coronavirus 2 is a major global health issue and is driving the need for new therapeutics.The surface spike protein,which plays a central role in virus infection,is current...Severe acute respiratory syndrome-associated coronavirus 2 is a major global health issue and is driving the need for new therapeutics.The surface spike protein,which plays a central role in virus infection,is currently the target for vaccines and neutralizing treatments.The emergence of novel variants with multiple mutations in the spike protein may reduce the effectiveness of neutralizing antibodies by altering the binding activity of the protein with angiotensin-converting enzyme 2(ACE2).To understand the impact of spike protein mutations on the binding interactions required for virus infection and the effectiveness of neutralizing monoclonal antibody(mAb)therapies,the binding activities of the original spike protein receptor binding domain(RBD)sequence and the reported spike protein variants were investigated using surface plasmon resonance.In addition,the interactions of the ACE2 receptor,an antispike mAb(mAb1),a neutralizing mAb(mAb2),the original spike RBD sequence,and mutants D614G,N501Y,N439K,Y453F,and E484K were assessed.Compared to the original RBD,the Y453F and N501Y mutants displayed a significant increase in ACE2 binding affinity,whereas D614G had a substantial reduction in binding affinity.All mAb-RBD mutant proteins displayed a reduction in binding affinities relative to the original RBD,except for the E484K-mAb1 interaction.The potential neutralizing capability of mAb1 and mAb2 was investigated.Accordingly,mAb1 failed to inhibit the ACE2-RBD interaction while mAb2 inhibited the ACE2-RBD interactions for all RBD mutants,except mutant E484K,which only displayed partial blocking.展开更多
基金National Key Technologies Research & Development Program of China(No.2006BAK03A09)National Basic Research Program of China(No.2007CB714503)Science and Technology Development Program of Jilin Province, China (No.20060706)
文摘A novel immunosensor based on surface plasmon resonance（SPR） has been developed for the recognition of antigen. The sensor was designed on the basis of the fixed angle of incidence and measuring the reflected intensities in a wavelength range of 430--750 nm in real-time. An ultra-bright white light-emitting diode（LED） was used as the light source. Molecular self-assembling in solution was used to form the sensing membrane on gold substrate. It has been seen that the sensitivity of the SPR sensor with 3-mercaptopropionic acid（MPA）/protein A（SPA） sensing membrane is considerably higher than that with MPA or SPA modified sensing membrane. The kinetic processes on the sensing membrane were studied. The human B factor（Bf）, an activator of complement 3（C3）, was recognized among the other antigens. This sensor can also be used for other antigen/antibody or adaptor/receptor recognition. Under optimized experimental conditions, the sensor has good selectivity, repeatability, and reversibility.
基金supported by the National Natural Science Foundation of China(Nos.21975098 and 22275071)the program for JLU Science and Technology Innovative Research Team(No.2017TD-06)the opening funds of State Key Laboratory of Applied Optics,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Science,and the China Postdoctoral Science Foundation(Nos.2020TQ0119 and 2020M681046).
文摘Plasmonic enhanced fluorescence(PEF)technology is a powerful strategy to improve the sensitivity of immunofluorescence microarrays(IFMA),however,current approaches to constructing PEF platforms are either expensive/time-consuming or reliant on specialized instruments.Here,we develop a completely alternative approach relying on a two-step protocol that includes the self-assembly of gold nanoparticles(GNPs)at the water–oil interface and subsequent annealing-assisted regulation of gold nanogap.Our optimized thermal-annealing GNPs(TA-GNP)platform generates adequate hot spots,and thus produces high-density electromagnetic coupling,eventually enabling 240-fold fluorescence enhancement of probed dyes in the near-infrared region.For clinical detection of human samples,TA-GNP provides super-high sensitivity and low detection limits for both hepatitis B surface antigen and SARS-CoV-2 binding antibody,coupled with a much-improved detection dynamic range up to six orders of magnitude.With fast detection,high sensitivity,and low detection limit,TA-GNP could not only substantially improve the outcomes of IFMA-based precision medicine but also find applications in fields of proteomic research and clinical pathology.
文摘Severe acute respiratory syndrome-associated coronavirus 2 is a major global health issue and is driving the need for new therapeutics.The surface spike protein,which plays a central role in virus infection,is currently the target for vaccines and neutralizing treatments.The emergence of novel variants with multiple mutations in the spike protein may reduce the effectiveness of neutralizing antibodies by altering the binding activity of the protein with angiotensin-converting enzyme 2(ACE2).To understand the impact of spike protein mutations on the binding interactions required for virus infection and the effectiveness of neutralizing monoclonal antibody(mAb)therapies,the binding activities of the original spike protein receptor binding domain(RBD)sequence and the reported spike protein variants were investigated using surface plasmon resonance.In addition,the interactions of the ACE2 receptor,an antispike mAb(mAb1),a neutralizing mAb(mAb2),the original spike RBD sequence,and mutants D614G,N501Y,N439K,Y453F,and E484K were assessed.Compared to the original RBD,the Y453F and N501Y mutants displayed a significant increase in ACE2 binding affinity,whereas D614G had a substantial reduction in binding affinity.All mAb-RBD mutant proteins displayed a reduction in binding affinities relative to the original RBD,except for the E484K-mAb1 interaction.The potential neutralizing capability of mAb1 and mAb2 was investigated.Accordingly,mAb1 failed to inhibit the ACE2-RBD interaction while mAb2 inhibited the ACE2-RBD interactions for all RBD mutants,except mutant E484K,which only displayed partial blocking.
