Integrating Colloidal Quantum Dots with Porous Silicon for High Sensitivity Biosensing

2011 ◽  
Vol 1301 ◽  
Author(s):  
Girija Gaur ◽  
Dmitry Koktysh ◽  
Sharon M. Weiss
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
High Sensitivity ◽  
Detection Sensitivity ◽  
Detection Scheme ◽  
Mode Detection ◽  
Cdte Qds ◽  
Refractive Index Increase

ABSTRACTWe aim to utilize the high surface area of a porous silicon (PSi) matrix coupled with semiconductor quantum dot (QD) amplifiers for ultrasensitive optical detection of small biomolecules using a dual-mode detection scheme. In our system, QDs attached to the target biomolecule serve as signal amplifiers by providing an additional refractive index increase beyond that of the smaller target molecules. The strong photoluminescence (PL) from the QDs serves as a secondary indication of target molecule attachment in the pores. A resulting increase in optical thickness of ∼190 nm and detection sensitivity of ∼700 nm/RIU have been demonstrated for attachment of glutathione capped CdTe QDs in the porous silicon matrix. Reflectance and PL measurements, combined with simulations, have been used to characterize the surface area coverage of the QDs within the porous framework, which is estimated at 10% for glutathione capped CdTe QDs.

scholarly journals High surface area of porous silicon drives desorption of intact molecules

2007 ◽  
Vol 18 (11) ◽  
pp. 1945-1949 ◽  
Author(s):  
Trent R. Northen ◽  
Hin-Koon Woo ◽  
Michael T. Northen ◽  
Anders Nordström ◽  
Winnie Uritboonthail ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area

Sensitive, Selective, & Tunable Porous Silicon Gas Sensor

2004 ◽  
Vol 828 ◽  
Author(s):  
Stephen Lewis ◽  
James Gole ◽  
Peter J. Hesketh
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
Gas Sensor ◽  
Linear Response ◽  
High Surface ◽  
High Surface Area ◽  
Gas Response ◽  
Nanoporous Layer ◽  
General Method ◽  
Fft Analysis

ABSTRACTHybrid porous silicon, consisting of a microporous framework whose walls are covered with a thin nanoporous layer, proves to be an inexpensive and robust platform for fabrication of rapid, reversible, and sensitive semiconductor sensors. An extremely high surface area provides a mechanism for the detection of ppm and ppb levels of a range of gases including ammonia, NOx, and CO. A general method of coating electroless metal onto the surface provides a basis for nanostructure induced selectivity between these gases. Further, the introduction of FFT analysis to the rapidly reversible and linear response of the porous silicon gas sensor allows the gas response to be acquired and filtered on a drifting baseline.

Extremely High Surface Area Metallurgical-Grade Porous Silicon Powder Prepared by Metal-Assisted Etching

2011 ◽  
Vol 14 (5) ◽  
pp. K25 ◽  
Author(s):  
A. Loni ◽  
D. Barwick ◽  
L. Batchelor ◽  
J. Tunbridge ◽  
Y. Han ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Silicon Powder

High sensitivity, high surface area Enzyme-linked Immunosorbent Assay (ELISA)

2015 ◽  
Vol 26 (3-4) ◽  
pp. 115-127 ◽  
Author(s):  
Harpal Singh ◽  
Takahiro Morita ◽  
Yuma Suzuki ◽  
Masayuki Shimojima ◽  
An Le Van ◽  
...  
Keyword(s):  
Surface Area ◽  
Immunosorbent Assay ◽  
High Surface ◽  
High Surface Area ◽  
High Sensitivity ◽  
Enzyme Linked Immunosorbent Assay

Synthesis and Characterization of Mesoporous Silicon Spheres from Solid Silica Spheres

2011 ◽  
Vol 675-677 ◽  
pp. 1069-1072 ◽  
Author(s):  
Jiang Zhu ◽  
Chang Gong Meng
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
Quantum Confinement Effect ◽  
Single Point ◽  
High Surface ◽  
High Surface Area ◽  
Silica Spheres ◽  
Mesoporous Silicon ◽  
Silicon Spheres

A well known method was used to convert the solid silica spheres to porous silicon spheres with high surface area, with the starting shape retained. The presented work demonstrated that the porous silicon spheres are composed of polycrystal morphology. Due to the quantum confinement effect, the photoluminescence emission centered at 621 nm. The results of N2 adsorption and desorption analysis indicates the mesoporous silicon spheres possess a surface area around 88 m2 g-1 and single point micro-pore volume 0.173 cm3 g-1.

Synthesis of High Surface Area Porous Silicon Carbide by Employing Soft Template in the Sol-Gel Process

2010 ◽  
Vol 148-149 ◽  
pp. 1629-1633
Author(s):  
Dong Hua Wang ◽  
Xin Fu
Keyword(s):  
Silicon Carbide ◽  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Silica Xerogel ◽  
Porous Silicon Carbide ◽  
Gel Method ◽  
Sol Gel Process

High surface area porous silicon carbide was synthesized by a modified sol-gel method. In the sol-gel method, furfuryl alcohol and tetraethoxysilane were used respectively as carbon and silicon precursors for preparing a carbonaceous silica xerogel. Polymethylhydrosiloxane (PMHS) was employed as pore-adjusting agent in the sol-gel process. SiC was obtained by the carbothermal reduction of the carbonaceous silica xerogel at 1300 oC in argon flow and then purified by removing excess silica, carbon and other impurities. XRD、FTIR、SEM、HRTEM and BET were used to characterize the SiC samples. The results show that the SiC products are found to have high specific surface area of 135 m2 /g. PMHS has important effect on the surface area, pore volume of the SiC products. It is therefore suggested that PMHS plays the role of structure-directing agent that enhances the production of mesoporous pores in the SiC products.

scholarly journals 3D Fuzzy Graphene Microelectrode Array for Neurotransmitter Sensing at Sub-cellular Spatial Resolution

2020 ◽  
Author(s):  
Elisa Castagnola ◽  
Raghav Garg ◽  
Sahil Rastogi ◽  
Tzahi Cohen-Karni ◽  
Xinyan Tracy Cui
Keyword(s):  
Surface Area ◽  
Spatial Resolution ◽  
Microelectrode Array ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Brain Functions

<div>Dopamine (DA) is a monoamine neurotransmitter involved in the modulation of various physiological brain functions, including learning, motivation, reward, and motor functions. The development of a high sensitivity real-time sensor for multi-site detection of DA with high spatial resolution has critical implications for both neuroscience and clinical communities to improve understanding and treatments of neurological and neuropsychiatric disorders. Here, we present high-surface area out-of-plane grown three-dimensional (3D) fuzzy graphene (3DFG) microelectrode arrays (MEAs) for highly selective, sensitive, and stable DA electrochemical sensing. 3DFG microelectrodes present a remarkable sensitivity to DA (2.87 ± 0.25 nA/nM, with</div><div>LOD of 990±15 pM), the highest reported for nanocarbon MEAs using Fast Scan Cyclic Voltammetry (FSCV). The high surface area of 3DFG allows for miniaturization of electrode down to 2 x 2 μm^2, without compromising the electrochemical performance. Moreover, 3DFG MEAs are electrochemically stable under 7.2 million scans of continuous FSCV cycling, present exceptional selectivity over the most common interferents in vitro with minimum fouling by electrochemical byproducts, and can discriminate DA and serotonin (5-HT) in response to the injection of their 50:50 mixture. These results highlight the potential of 3DFG MEAs as a promising platform for FSCV based multi-site detection of DA with high sensitivity, selectivity, and spatial resolution.</div>

High Sensitivity Sensor Based on Porous Silicon Waveguide

2006 ◽  
Vol 934 ◽  
Author(s):  
Guoguang Rong ◽  
Jarkko J. Saarinen ◽  
John E. Sipe ◽  
Sharon M. Weiss
Keyword(s):  
Porous Silicon ◽  
Waveguide Mode ◽  
Incident Light ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
High Sensitivity ◽  
Silicon Waveguide ◽  
Spr Sensor ◽  
Waveguide Coupling

ABSTRACTPorous 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.

High Sensitivity Photonic Crystal Biosensor Incorporating Nanorod Structures for Enhanced Surface Area

2007 ◽  
Vol 1010 ◽  
Author(s):  
Wei Zhang ◽  
Nikhil Ganesh ◽  
Ian D. Block ◽  
Brian T. Cunningham
Keyword(s):  
Photonic Crystal ◽  
Surface Area ◽  
Mass Density ◽  
High Surface ◽  
High Surface Area ◽  
High Sensitivity ◽  
Porous Titanium ◽  
Glancing Angle ◽  
Adsorbed Mass ◽  
Enhanced Surface

AbstractWe report efforts at enhancement of the surface area of a photonic crystal biosensor through incorporation of a porous titanium dioxide film into the device. The film possessing the structure of nanorods is deposited by the glancing angle deposition technique. Results for detection of polymer films, large proteins and small molecules indicate up to a four-fold enhancement of detected adsorbed mass density for high surface area sensors, compared with sensors without the high surface area coating.

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