Flow-through nanohole array based sensor implemented on analogue smartphone components

Gomez-Cruz, Juan; Nair, Srijit; Ascanio, Gabriel; Escobedo, Carlos

doi:10.1117/12.2272433

Cited by 3 publications

(1 citation statement)

References 20 publications

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“…Nanoplasmonic sensors supporting surface plasmon resonance (SPR) have been employed in various biosensing applications in the past [19][20][21][22][23][24][25]. In terms of design of POC devices, metallic nanostructures such as surface relief gratings (SRGs) offer several key advantages including very small footprint, portability and compatibility with collinear optics providing easiness of integration with other microsystems [26,27].…”

Section: Introductionmentioning

confidence: 99%

Selective Uropathogenic <em>E. coli</em> Detection using Crossed Surface Relief Gratings

Nair

Gomez-Cruz

Manjarrez-Hernández

et al. 2018

Preprint

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Given the rise in the number of cases and their recurrences, Urinary Tract Infections (UTI) are one of the major burdens on public healthcare worldwide. Rapid, inexpensive and selective detection of Uropathogenic E. coli (UPEC), a major contributor to UTIs, is the need of the hour for effective treatment, given the rise of antibiotic-resistant bacteria due to improper diagnosis. Here we present a rapid, real-time, selective and label-free detection of UPEC using an integrated sensing platform based on Crossed Surface Relief Gratings (CSRGs) as nanoplasmonic sensors. Detection is achieved due to the unique Surface Plasmon Resonance (SPR)-based light energy exchange attributed to the CSRGs, allowing real-time sensing in a very narrow bandwidth of the incident light to pass where the SPR energy conversion occurs. The sensing ability of the platform is experimentally demonstrated by the detection of bulk Refractive Index (RI) changes, with a bulk sensitivity of 382.2 nm/RIU and a resolution in the order of 10-6 RIU. We demonstrate selective capture and detection of clinical concentration of UPEC, as opposed to other gram-negative bacteria, in real-time, a first for CSRGs. This work is particularly important for effective treatment of UTIs, allowing point-of-care diagnosis for economically disadvantaged regions around the world.

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Section: Introductionmentioning

confidence: 99%

Selective Uropathogenic <em>E. coli</em> Detection using Crossed Surface Relief Gratings

Nair

Gomez-Cruz

Manjarrez-Hernández

et al. 2018

Preprint

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Structural Stability of Optofluidic Nanostructures in Flow-Through Operation

2020

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Optofluidic sensors based on periodic arrays of subwavelength apertures that support surface plasmon resonance can be employed as both optical sensors and nanofluidic structures. In flow-through operation, the nanoapertures experience pressure differences across the substrate in which they are fabricated, which imposes the risk for structural failure. This work presents an investigation of the deflection and structural stability of nanohole array-based optofluidic sensors operating in flow-through mode. The analysis was approached using experiments, simulations via finite element method, and established theoretical models. The results depict that certain areas of the sensor deflect under pressure, with some regions suffering high mechanical stress. The offset in the deflection values between theoretical models and actual experimental values is overturned when only the effective area of the substrate, of 450 µm, is considered. Experimental, theoretical, and simulation results suggest that the periodic nanostructures can safely operate under trans-membrane pressures of up to 20 psi, which induce deflections of up to ~20 μm.

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Selective Uropathogenic E. coli Detection Using Crossed Surface-Relief Gratings

Nair

Gomez-Cruz

Manjarrez-Hernández

et al. 2018

Sensors

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Urinary tract infections (UTIs) are one of the major burdens on public healthcare worldwide. One of the primary causes of UTIs is the invasion of the urinary tract by uropathogenic Escherichia coli (UPEC). Improper treatment of bacterial infections like UTIs with broad-spectrum antibiotics has contributed to the rise of antimicrobial resistance, necessitating the development of an inexpensive, rapid and accurate detection of UPEC. Here, we present real-time, selective and label-free detection of UPEC using crossed surface-relief gratings (CSRGs) as nanometallic sensors incorporated into an optical sensing platform. CSRGs enable real-time sensing due to their unique surface plasmon resonance (SPR)-based light energy exchange, resulting in detection of a very-narrow-bandwidth SPR signal after the elimination of residual incident light. The platform’s sensing ability is experimentally demonstrated by the detection of bulk refractive index (RI) changes, with a bulk sensitivity of 382.2 nm/RIU and a resolution in the order of 10−6 RIU. We also demonstrate, for the first time, CSRG-based real-time selective capture and detection of UPEC in phosphate-buffered saline (PBS) solution, in clinically relevant concentrations, as opposed to other UTI-causing Gram-negative bacteria. The platform’s detection limit is calculated to be 105 CFU/mL (concentration on par with the clinical threshold for UTI diagnosis), with a dynamic range spanning four orders of magnitude. This work paves the way for the development of inexpensive point-of-care diagnosis devices focusing on effective treatment of UTIs, which are a burden on public healthcare due to the rise in the number of cases and their recurrences in the recent past.

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Flow-through nanohole array based sensor implemented on analogue smartphone components

Cited by 3 publications

References 20 publications

Selective Uropathogenic <em>E. coli</em> Detection using Crossed Surface Relief Gratings

Selective Uropathogenic <em>E. coli</em> Detection using Crossed Surface Relief Gratings

Structural Stability of Optofluidic Nanostructures in Flow-Through Operation

Selective Uropathogenic E. coli Detection Using Crossed Surface-Relief Gratings

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