Optical devices are highly attractive for biosensing as they can not only enable quantitative measurements of analytes but also provide information on molecular structures.Unfortunately,typical refractive index-based ...Optical devices are highly attractive for biosensing as they can not only enable quantitative measurements of analytes but also provide information on molecular structures.Unfortunately,typical refractive index-based optical sensors do not have sufficient sensitivity to probe the binding of low-molecular-weight analytes.Non-optical devices such as field-effect transistors can be more sensitive but do not offer some of the significant features of optical devices,particularly molecular fingerprinting.We present optical conductivity-based mid-infrared(mid-IR)biosensors that allow for sensitive and quantitative measurements of low-molecular-weight analytes as well as the enhancement of spectral fingerprints.The sensors employ a hybrid metasurface consisting of monolayer graphene and metallic nano-antennas and combine individual advantages of plasmonic,electronic and spectroscopic approaches.First,the hybrid metasurface sensors can optically detect target molecule-induced carrier doping to graphene,allowing highly sensitive detection of low-molecular-weight analytes despite their small sizes.Second,the resonance shifts caused by changes in graphene optical conductivity is a well-defined function of graphene carrier density,thereby allowing for quantification of the binding of molecules.Third,the sensor performance is highly stable and consistent thanks to its insensitivity to graphene carrier mobility degradation.Finally,the sensors can also act as substrates for surfaceenhanced infrared spectroscopy.We demonstrated the measurement of monolayers of sub-nanometer-sized molecules or particles and affinity binding-based quantitative detection of glucose down to 200 pM(36 pg/mL).We also demonstrated enhanced fingerprinting of minute quantities of glucose and polymer molecules.展开更多
基金supported by the National Science Foundation(grants no.ECCS-1509760 and ECCS-1307948)a Defense Advanced Research Projects Agency Young Faculty Award(grant no.D15AP00111)+1 种基金the Air Force Office of Scientific Research(grants no.FA9550–14–1–0389 and FA9550–16–1–0322)Research was carried out in part at the Center for Functional Nanomaterials,Brookhaven National Laboratory,which is supported by the US Department of Energy,Office of Basic Energy Sciences(contract no.DE-SC0012704).
文摘Optical devices are highly attractive for biosensing as they can not only enable quantitative measurements of analytes but also provide information on molecular structures.Unfortunately,typical refractive index-based optical sensors do not have sufficient sensitivity to probe the binding of low-molecular-weight analytes.Non-optical devices such as field-effect transistors can be more sensitive but do not offer some of the significant features of optical devices,particularly molecular fingerprinting.We present optical conductivity-based mid-infrared(mid-IR)biosensors that allow for sensitive and quantitative measurements of low-molecular-weight analytes as well as the enhancement of spectral fingerprints.The sensors employ a hybrid metasurface consisting of monolayer graphene and metallic nano-antennas and combine individual advantages of plasmonic,electronic and spectroscopic approaches.First,the hybrid metasurface sensors can optically detect target molecule-induced carrier doping to graphene,allowing highly sensitive detection of low-molecular-weight analytes despite their small sizes.Second,the resonance shifts caused by changes in graphene optical conductivity is a well-defined function of graphene carrier density,thereby allowing for quantification of the binding of molecules.Third,the sensor performance is highly stable and consistent thanks to its insensitivity to graphene carrier mobility degradation.Finally,the sensors can also act as substrates for surfaceenhanced infrared spectroscopy.We demonstrated the measurement of monolayers of sub-nanometer-sized molecules or particles and affinity binding-based quantitative detection of glucose down to 200 pM(36 pg/mL).We also demonstrated enhanced fingerprinting of minute quantities of glucose and polymer molecules.
