Macroporous Silicon Microcavities for Macromolecule Detection

Ouyang, Huimin; Christophersen, M.; Viard, R.; Miller, Benjamin L.; Fauchet, Philippe M.

doi:10.1002/adfm.200500218

Cited by 228 publications

(209 citation statements)

References 42 publications

(43 reference statements)

Supporting

Mentioning

205

Contrasting

Order By: Relevance

“…A decrease in the ability to bind streptavidin was observed for surface concentrations of biotin above 50% and was attributed to steric crowding within the biotin layer. 19 In this study we leverage the optical response of the PSi sensor to directly investigate each layer of a sandwich assay which attaches a biotinylated receptor antibody to the biotin/SA linking chemistry in order to optimize target detection. Taking a "bottom-up" approach we observe strong steric crowding effects in each layer of the receptor linking stack (biotin/SA/receptor) and identify distinct differences when compared to results reported on planar gold surfaces.…”

Section: (Equation 1)mentioning

confidence: 99%

“…12 Recently, Ouyang et al 19 observed steric crowding when binding SA to biotin in a PSi optical sensor 13 , but the effect was not characterized in detail. In this study we characterize the effect of each layer in the sandwich assay on the immobilization of the subsequent layer with the goal of optimizing IgG target detection sensitivity.…”

Section: Optimization Of Linking Chemistry To Maximize Igg Target Detmentioning

confidence: 99%

“…17 Many groups have proved the use of PSi as an optical biosensing substrate. 2, 18,19,20 The amount of biological material linkedto the internal surface area causes a decrease in the porosity of the porous device thatcan be monitored by a shift in refractive index. Porosity can be related to refractive index by the Bruggeman effective medium approximation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Steric Crowding Effects on Target Detection in an Affinity Biosensor

Bonanno

DeLouise

2007

Langmuir

View full text Add to dashboard Cite

This work quantifies the impact of steric crowding on whole antibody (Ab) receptor immobilization and target Ab detection and also demonstrates how the versatile biotin/streptavidin receptor immobilization system must be tuned to optimize target detection in designing biosensors. Results are demonstrated on a label-free optical biosensor comprised of n-type macroporous porous silicon (PSi) with ∼88-107 nm diameter pores. We employ a sandwich assay scheme comprised of a linking chemistry (biotin/streptavidin) to attach biotinylated anti-rabbit IgG (receptor) to detect rabbit IgG (target). A "bottoms-up" approach was taken to investigate each layer of the sandwich assay to optimize target binding. Steric crowding was observed to hinder subsequent layer binding for each layer in the sandwich (biotin, streptavidin, and receptor). Our results give definitive evidence that onset of steric crowding within the biotin layer occurs at a surface coverage of 57% which is much higher compared to published work on well ordered self-assembled biotin monolayers on planar gold surfaces. This difference is attributed to the topographical heterogeneity of the PSi substrate. Streptavidin binding to surface-linked biotin was altered by preblocking streptavidin binding sites with biotin. Through consistent trends in data, preblocking SA was shown to reduce steric crowding within the SA layer, which translated into increased receptor immobilization. The final detection range of rabbit IgG was 0.07-3 mg ml -1 (0.23-9.8 μg mm -2 ) and binding specificity was demonstrated employing anti-chicken IgG control receptor. This study underlines the importance of considering binding avidity and surface topography in optimizing chip-based biosensors.

show abstract

Section: (Equation 1)mentioning

confidence: 99%

Section: Optimization Of Linking Chemistry To Maximize Igg Target Detmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Steric Crowding Effects on Target Detection in an Affinity Biosensor

Bonanno

DeLouise

2007

Langmuir

View full text Add to dashboard Cite

show abstract

“…However, since a thin film is not a resonant structure, the sensitivity of the single layer PSi biosensor is limited as there is no sharp feature in the optical spectrum for which to accurately monitor small reflectance shifts. Multilayer PSi microcavities have also been used to detect various biomolecules [6] [7]. The drawback of these devices is their several micron thickness, which increases the infiltration time.…”

Section: Introductionmentioning

confidence: 99%

High Sensitivity Sensor Based on Porous Silicon Waveguide

et al. 2006

View full text Add to dashboard Cite

Porous silicon (PSi) waveguides are fabricated as a new platform for high sensitivity biosensors. Biomolecules infiltrated into the PSi waveguide increase the effective refractive index of the waveguide and change the angle at which incident light couples into a waveguide mode. Due to the high surface area to volume ratio of PSi and the confinement of optical energy in the region where the biomolecules reside, the waveguide resonance is very sensitive to small concentrations of infiltrated molecular species. A resonance width below 0.1˚ has been obtained, which is sufficient to detect one monolayer of DNA covering the pore walls. In this work, a prism is used for the waveguide coupling in an arrangement that is similar to traditional surface plasmon resonance (SPR) sensing. Theoretical analysis suggests that an optimized PSi waveguide resonant sensor will show a 60-fold improvement in sensitivity when compared to a conventional SPR sensor due to the enhanced interaction between the electromagnetic field and biological material.

show abstract

“…This principle is applied in porous biosensors [6]. If the pores are filled with an optically tunable medium, then the optical properties of the PSi sample also become tunable.…”

Section: Introductionmentioning

confidence: 99%

Thermal tuning of a thin-film optical filter based on porous silicon and liquid crystal

Tkachenko¹,

Shulika²

2010

Ukr. J. Phys. Opt.

View full text Add to dashboard Cite

Spectral characteristics of an interference optical filter based on a free-standing mesoporous silicon film containing nematic liquid crystal E7 are studied experimentally. The porous structure represents two distributed Bragg reflectors divided by a quarter-wave microcavity having a resonance near 1600 nm. Optical transmission spectra of the filter are measured in the temperature range from 27°C to 80°C. For the temperatures less than 62 o C (a clearing point of the liquid crystal), we have observed continuous red shift of resonant wavelength of the microcavity in the range of 11 nm. The thermal dependence of the shift measured by us has sharply increasing slope near the clearing point. The resonant wavelength of the microcavity exhibits a slow linear decrease for the temperatures exceeding 62 o C. We have also studied the spectra of the filter under local heating of the sample by a laser. Our results demonstrate that the laser beam with the power of 100 mW provides total tuning of the microcavity.

show abstract

Macroporous Silicon Microcavities for Macromolecule Detection

Cited by 228 publications

References 42 publications

Steric Crowding Effects on Target Detection in an Affinity Biosensor

Steric Crowding Effects on Target Detection in an Affinity Biosensor

High Sensitivity Sensor Based on Porous Silicon Waveguide

Thermal tuning of a thin-film optical filter based on porous silicon and liquid crystal

Contact Info

Product

Resources

About