An efficient technique for the reduction of wavelength noise in resonance-based integrated photonic sensors

The Analyst ◽  
2014 ◽  
Vol 139 (22) ◽  
pp. 5901-5910 ◽  
Author(s):  
Farshid Ghasemi ◽  
Maysamreza Chamanzar ◽  
Ali A. Eftekhar ◽  
Ali Adibi

A systematic study of the limit of detection (LOD) in resonance-based silicon photonic lab-on-chip sensors is presented.

Biosensors ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 202
Author(s):  
Rosario Iemmolo ◽  
Valentina La Cognata ◽  
Giovanna Morello ◽  
Maria Guarnaccia ◽  
Mariamena Arbitrio ◽  
...  

Background: Antineoplastic agents represent the most common class of drugs causing Adverse Drug Reactions (ADRs). Mutant alleles of genes coding for drug-metabolizing enzymes are the best studied individual risk factors for these ADRs. Although the correlation between genetic polymorphisms and ADRs is well-known, pharmacogenetic tests are limited to centralized laboratories with expensive or dedicated instrumentation used by specialized personnel. Nowadays, DNA chips have overcome the major limitations in terms of sensibility, specificity or small molecular detection, allowing the simultaneous detection of several genetic polymorphisms with time and costs-effective advantages. In this work, we describe the design of a novel silicon-based lab-on-chip assay able to perform low-density and high-resolution multi-assay analysis (amplification and hybridization reactions) on the In-Check platform. Methods: The novel lab-on-chip was used to screen 17 allelic variants of three genes associated with adverse reactions to common chemotherapeutic agents: DPYD (Dihydropyrimidine dehydrogenase), MTHFR (5,10-Methylenetetrahydrofolate reductase) and TPMT (Thiopurine S-methyltransferase). Results: Inter- and intra assay variability were performed to assess the specificity and sensibility of the chip. Linear regression was used to assess the optimal hybridization temperature set at 52 °C (R2 ≈ 0.97). Limit of detection was 50 nM. Conclusions: The high performance in terms of sensibility and specificity of this lab-on-chip supports its further translation to clinical diagnostics, where it may effectively promote precision medicine.


Author(s):  
Jesus Rodriguez-Manzano ◽  
Kenny Malpartida-Cardenas ◽  
Nicolas Moser ◽  
Ivana Pennisi ◽  
Matthew Cavuto ◽  
...  

AbstractThe COVID-19 pandemic is a global health emergency characterized by the high rate of transmission and ongoing increase of cases globally. Rapid point-of-care (PoC) diagnostics to detect the causative virus, SARS-CoV-2, are urgently needed to identify and isolate patients, contain its spread and guide clinical management. In this work, we report the development of a rapid PoC diagnostic test (< 20 min) based on reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) and semiconductor technology for the detection of SARS-CoV-2 from extracted RNA samples. The developed LAMP assay was tested on a real-time benchtop instrument (RT-qLAMP) showing a lower limit of detection of 10 RNA copies per reaction. It was validated against 183 clinical samples including 127 positive samples (screened by the CDC RT-qPCR assay). Results showed 90.55% sensitivity and 100% specificity when compared to RT-qPCR and average positive detection times of 15.45 ± 4.43 min. For validating the incorporation of the RT-LAMP assay onto our PoC platform (RT-eLAMP), a subset of samples was tested (n=40), showing average detection times of 12.89 ± 2.59 min for positive samples (n=34), demonstrating a comparable performance to a benchtop commercial instrument. Paired with a smartphone for results visualization and geo-localization, this portable diagnostic platform with secure cloud connectivity will enable real-time case identification and epidemiological surveillance.One Sentence SummaryWe demonstrate isothermal detection of SARS-CoV-2 in under 20 minutes from extracted RNA samples with a handheld Lab-on-Chip platform.


2021 ◽  
Author(s):  
Shaik Ahmadsaidulu ◽  
B. Vamsi Krsihna ◽  
B V V Satyanarayana ◽  
Durga Prakash Matta

Abstract Cardiac arrests are one of the major health problems in present days. Cardiac Troponin-I (cTnI) is one of the important enzymes that causes cardiac arrest. Early diagnosis and proper medication of this saves human life. One of the prominent devices to diagnose troponin I is FET based bio-sensor. Normally, for these sensors’ higher sensitivities will be obtained as these biosensors structure consists of nanowire FETs. Proper selection of materials, dimensions, and doping concentrations of nanowire FET imply the perfection of a nanowire FET-based biosensor. In this work, Silicon Nanowire (SiNW) FET sensor is designed and simulated using COMSOL Multiphysics. Through this design, Identified the presence of different concentrations of cTnI present in human blood. The presence of different enzymes like cTnT, cTnI etc., bring changes in characteristics of SiNW FET sensor. With these changes in characteristics, we can identify the presence of these enzymes of a lower concentration also. The lower concentrations of these biomarkers will bring notable changes in the drain current. The characteristics were analysed with the SiNW FET which is equipped with immobilized antibodies on it. The considerable changes observed in these characteristics of FET sensor identifies the presence of cTnI biomarker and are attached to the monoclonal Antibodies (mAb). Our observations shown that the properties of designed SiNW FET changes with presence of these bio marker materials and a limit of detection is obtained the order of 2pg/mL. with further the design bio sensor with SiNW FET can be used for microfluidic and Lab-on-Chip applications also.


Lab on a Chip ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 178-185 ◽  
Author(s):  
Jessica Francis ◽  
Isaac Stamper ◽  
Jason Heikenfeld ◽  
Eliot F. Gomez

A digital flowmetry sensor is fabricated with low limit of detection and wide dynamic range, that is suitable for lab-on-chip or wearable sweat sensing systems.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7210
Author(s):  
Manasa Nandimandalam ◽  
Francesca Costantini ◽  
Nicola Lovecchio ◽  
Lorenzo Iannascoli ◽  
Augusto Nascetti ◽  
...  

Innovative materials for the integration of aptamers in Lab-on-Chip systems are important for the development of miniaturized portable devices in the field of health-care and diagnostics. Herein we highlight a general method to tailor an aptamer sequence in two subunits that are randomly immobilized into a layer of polymer brushes grown on the internal surface of microfluidic channels, optically aligned with an array of amorphous silicon photosensors for the detection of fluorescence. Our approach relies on the use of split aptamer sequences maintaining their binding affinity to the target molecule. After binding the target molecule, the fragments, separately immobilized to the brush layer, form an assembled structure that in presence of a “light switching” complex [Ru(phen)2(dppz)]2+, emit a fluorescent signal detected by the photosensors positioned underneath. The fluorescent intensity is proportional to the concentration of the target molecule. As proof of principle, we selected fragments derived from an aptamer sequence with binding affinity towards ATP. Using this assay, a limit of detection down to 0.9 µM ATP has been achieved. The sensitivity is compared with an assay where the original aptamer sequence is used. The possibility to re-use both the aptamer assays for several times is demonstrated.


Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 861
Author(s):  
Benjamin J. Murphy ◽  
Edward A. Luy ◽  
Katerina L. Panzica ◽  
Gregory Johnson ◽  
Vincent J. Sieben

Reagent-based colorimetric analyzers often heat the fluid under analysis for improved reaction kinetics, whilst also aiming to minimize energy use per measurement. Here, a novel method of conserving heat energy on such microfluidic systems is presented. Our design reduces heat transfer to the environment by surrounding the heated optical cell on four sides with integral air pockets, thereby realizing an insulated and suspended bridge structure. Our design was simulated in COMSOL Multiphysics and verified in a polymethyl methacrylate (PMMA) device. We evaluate the effectiveness of the insulated design by comparing it to a non-insulated cell. For temperatures up to 55 °C, the average power consumption was reduced by 49.3% in the simulation and 40.2% in the experiment. The designs were then characterized with the vanadium and Griess reagent assay for nitrate at 35 °C. Nitrate concentrations from 0.25 µM to 50 µM were tested and yielded the expected linear relationship with a limit of detection of 20 nM. We show a reduction in energy consumption from 195 J to 119 J per 10 min measurement using only 4 µL of fluid. Efficient heating on-chip will have broad applicability to numerous colorimetric assays.


2018 ◽  
pp. 83-102
Author(s):  
Mahmoud S. Rasras ◽  
Osama Al Mrayat

Nanophotonics ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 2377-2385 ◽  
Author(s):  
Zhao Cheng ◽  
Xiaolong Zhu ◽  
Michael Galili ◽  
Lars Hagedorn Frandsen ◽  
Hao Hu ◽  
...  

AbstractGraphene has been widely used in silicon-based optical modulators for its ultra-broadband light absorption and ultrafast optoelectronic response. By incorporating graphene and slow-light silicon photonic crystal waveguide (PhCW), here we propose and experimentally demonstrate a unique double-layer graphene electro-absorption modulator in telecommunication applications. The modulator exhibits a modulation depth of 0.5 dB/μm with a bandwidth of 13.6 GHz, while graphene coverage length is only 1.2 μm in simulations. We also fabricated the graphene modulator on silicon platform, and the device achieved a modulation bandwidth at 12 GHz. The proposed graphene-PhCW modulator may have potentials in the applications of on-chip interconnections.


2021 ◽  
pp. 2004101
Author(s):  
Marco Giacometti ◽  
Francesca Milesi ◽  
Pietro Lorenzo Coppadoro ◽  
Alberto Rizzo ◽  
Federico Fagiani ◽  
...  
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