Research

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13 pages, 3530 KiB

Open AccessArticle

Electrochemical Detection of Vibrio cholerae by Amine Functionalized Biocompatible Gadolinium Oxide Nanoparticles

by Ashutosh Kumar, Tamal Sarkar, Robin Kumar, Amulya K. Panda and Pratima R. Solanki

Micromachines 2023, 14(5), 995; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14050995 - 03 May 2023

Viewed by 1437

Herein, we report the biocompatible amine-functionalized gadolinium oxide nanoparticles (Gd₂O₃ NPs) for the possibility of electrochemical detection of Vibrio cholerae (Vc) cells. The microwave irradiation process is applied to synthesize Gd₂O₃ NPs. The amine (NH [...] Read more.

Herein, we report the biocompatible amine-functionalized gadolinium oxide nanoparticles (Gd₂O₃ NPs) for the possibility of electrochemical detection of Vibrio cholerae (Vc) cells. The microwave irradiation process is applied to synthesize Gd₂O₃ NPs. The amine (NH₂) functionalization is carried out via overnight stirring with 3(Aminopropyl)triethoxysilane (APTES) at 55 °C. The size of NPs amine functionalized APETS@Gd₂O₃ NPs are determined by transmission electron microscopy (TEM). APETS@Gd₂O₃ NPs are further electrophoretically deposited onto indium tin oxide (ITO) coated glass substrate to obtain working electrode surface. The monoclonal antibodies (anti-CT) specific to cholera toxin associated to Vc cells are covalently immobilized onto the above electrodes using EDC-NHS chemistry and further BSA is added to obtain the BSA/anti-CT/APETS@Gd₂O₃/ITO immunoelectrode. Further, this immunoelectrode shows the response for cells in CFU range from 3.125 × 10⁶ to 30 × 10⁶ and is very selective with sensitivity and LOD 5.07 mA CFUs mL cm⁻² and 0.9375 × 10⁶ CFU respectively. To establish a future potential for APTES@Gd₂O₃ NPs in field of biomedical applications and cytosensing, the effect of APTES@Gd₂O₃ NPs on mammalian cells is also observed using in vitro cytotoxicity assay and cell cycle analysis. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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18 pages, 8451 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Biomechanical Assessment of Red Blood Cells in Pulsatile Blood Flows

by Yang Jun Kang

Micromachines 2023, 14(2), 317; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14020317 - 26 Jan 2023

Cited by 2 | Viewed by 1971

Abstract

As rheological properties are substantially influenced by red blood cells (RBCs) and plasma, the separation of their individual contributions in blood is essential. The estimation of multiple rheological factors is a critical issue for effective early detection of diseases. In this study, three [...] Read more.

As rheological properties are substantially influenced by red blood cells (RBCs) and plasma, the separation of their individual contributions in blood is essential. The estimation of multiple rheological factors is a critical issue for effective early detection of diseases. In this study, three rheological properties (i.e., viscoelasticity, RBC aggregation, and blood junction pressure) are measured by analyzing the blood velocity and image intensity in a microfluidic device. Using a single syringe pump, the blood flow rate sets to a pulsatile flow pattern (Q_b[t] = 1 + 0.5 sin(2πt/240) mL/h). Based on the discrete fluidic circuit model, the analytical formula of the time constant (λ_b) as viscoelasticity is derived and obtained at specific time intervals by analyzing the pulsatile blood velocity. To obtain RBC aggregation by reducing blood velocity substantially, an air compliance unit (ACU) is used to connect polyethylene tubing (i.d. = 250 µm, length = 150 mm) to the blood channel in parallel. The RBC aggregation index (AI) is obtained by analyzing the microscopic image intensity. The blood junction pressure (β) is obtained by integrating the blood velocity within the ACU. As a demonstration, the present method is then applied to detect either RBC-aggregated blood with different concentrations of dextran solution or hardened blood with thermally shocked RBCs. Thus, it can be concluded that the present method has the ability to consistently detect differences in diluent or RBCs in terms of three rheological properties. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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12 pages, 2843 KiB

Open AccessArticle

A Disposable Screen Printed Electrodes with Hexagonal Ni(OH)₂ Nanoplates Embedded Chitosan Layer for the Detection of Depression Biomarker

by Satyanarayana Moru, Venishetty Sunil Kumar, Shekar Kummari and Kotagiri Yugender Goud

Micromachines 2023, 14(1), 146; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14010146 - 05 Jan 2023

Cited by 4 | Viewed by 1573

Abstract

Serotonin (5-hydroxytryptamine (5-HT)) is one of the important neurotransmitters which is released from the endocrine system. An abnormal level of this biomarker leads to several neurological diseases. The accurate assessment of serotonin is the utmost option to start treatment in the early stages [...] Read more.

Serotonin (5-hydroxytryptamine (5-HT)) is one of the important neurotransmitters which is released from the endocrine system. An abnormal level of this biomarker leads to several neurological diseases. The accurate assessment of serotonin is the utmost option to start treatment in the early stages of the disease. The current work is focused on the development of a disposable, screen-printed electrochemical sensor for the depression biomarker, serotonin in the physiological pH medium (pH 7.4) with the aid of a hexagonal, Ni(OH)₂-nanoplate (NH-HNP)-embedded chitosan (Chit) and modified, screen-printed carbon electrode (SPCE). Initially, hexagonal nanoplates of Ni(OH)₂ were synthesized by an eco-friendly and simple hydrothermal method. The prepared materials were well characterized by advanced analytical techniques to examine the physicochemical properties of the synthesized Ni(OH)₂ hexagonal nanoplates. From the cyclic voltametric (CV) analysis, it was found that the oxidative current response of 5-HT at a NH-HNP-modified SPCE has about fivefold higher current values than over bare SPCE. The scan rate studies of NH-HNP-Chit/SPCE electrodes revealed that the oxidation mechanism of 5-HT is controlled by the diffusion behavior of the analyte. Differential pulse voltammetric tests of the NH-HNP-Chit/SPCE electrode exhibited a linear response in the dynamic concentration range of 0.1 to 30 µM, with a detection limit of about 60 nM. The sensor response is very reproducible from electrode to electrode, and the deactivation or surface-fouling of the sensor was not observed within the several experimental measurements. The sensor exhibited excellent storage stability over a period of twenty days. Finally, the fabricated, disposable SPCE sensor has shown respectable activity for the detection of depression biomarker 5-HT from synthetic urine and saliva samples. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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12 pages, 3172 KiB

Open AccessArticle

Electrochemical Micro-Immunosensor of Cubic AuPt Dendritic Nanocrystals/Ti₃C₂-MXenes for Exosomes Detection

by Wenpo Feng, Pingping Xu, Mei Wang, Guidan Wang, Guangda Li and Aihua Jing

Micromachines 2023, 14(1), 138; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14010138 - 04 Jan 2023

Cited by 3 | Viewed by 1695

Abstract

Exosomes are extracellular vesicles that exist in body circulation as intercellular message transmitters. Although the potential of tumor-derived exosomes for non-invasive cancer diagnosis is promising, the rapid detection and effective capture of exosomes remains challenging. Herein, a portable electrochemical aptasensor of cubic AuPt [...] Read more.

Exosomes are extracellular vesicles that exist in body circulation as intercellular message transmitters. Although the potential of tumor-derived exosomes for non-invasive cancer diagnosis is promising, the rapid detection and effective capture of exosomes remains challenging. Herein, a portable electrochemical aptasensor of cubic AuPt dendritic nanocrystals (AuPt DNs)/Ti₃C₂ assisted in signal amplification, and aptamer CD63 modified graphene oxide (GO) was immobilized on a screen-printed carbon electrode (SPCE) as the substrate materials for the direct capture and detection of colorectal carcinoma exosomes. Cubic AuPt DNs/Ti₃C₂ was synthesized according to a simple hydrothermal procedure, and the AuPt DNs/Ti₃C₂-Apt hybrid demonstrated an efficient recognition of exosomes. Under optimal conditions, a detection limit of down to 20 exosomes µL⁻¹ was achieved with the linear range from 100 exosomes μL⁻¹ to 5.0 × 10⁵ exosomes μL⁻¹. The proposed immunosensor could be suitable for the analysis of exosomes and has clinical value in the early diagnosis of cancer. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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10 pages, 3230 KiB

Open AccessArticle

Enzyme Nanosheet-Based Electrochemical Aspartate Biosensor for Fish Point-of-Care Applications

by Thenmozhi Rajarathinam, Dinakaran Thirumalai, Sivaguru Jayaraman, Seonghye Kim, Minho Kwon, Hyun-jong Paik, Suhkmann Kim, Mijeong Kang and Seung-Cheol Chang

Micromachines 2022, 13(9), 1428; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13091428 - 29 Aug 2022

Cited by 1 | Viewed by 1551

Abstract

Bacterial infections in marine fishes are linked to mass mortality issues; hence, rapid detection of an infection can contribute to achieving a faster diagnosis using point-of-care testing. There has been substantial interest in identifying diagnostic biomarkers that can be detected in major organs [...] Read more.

Bacterial infections in marine fishes are linked to mass mortality issues; hence, rapid detection of an infection can contribute to achieving a faster diagnosis using point-of-care testing. There has been substantial interest in identifying diagnostic biomarkers that can be detected in major organs to predict bacterial infections. Aspartate was identified as an important biomarker for bacterial infection diagnosis in olive flounder (Paralichthys olivaceus) fish. To determine aspartate levels, an amperometric biosensor was designed based on bi-enzymes, namely, glutamate oxidase (GluOx) and aspartate transaminase (AST), which were physisorbed on copolymer reduced graphene oxide (P-rGO), referred to as enzyme nanosheets (GluOx-ASTENs). The GluOx-ASTENs were drop casted onto a Prussian blue electrodeposited screen-printed carbon electrode (PB/SPCE). The proposed biosensor was optimized by operating variables including the enzyme loading amount, coreactant (α-ketoglutarate) concentration, and pH. Under optimal conditions, the biosensor displayed the maximum current responses within 10 s at the low applied potential of −0.10 V vs. the internal Ag/AgCl reference. The biosensor exhibited a linear response from 1.0 to 2.0 mM of aspartate concentrations with a sensitivity of 0.8 µA mM⁻¹ cm⁻² and a lower detection limit of approximately 500 µM. Moreover, the biosensor possessed high reproducibility, good selectivity, and efficient storage stability. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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Review

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25 pages, 5364 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Point-of-Care Devices for Viral Detection: COVID-19 Pandemic and Beyond

by Sumit K. Yadav, Damini Verma, Ujala Yadav, Ashish Kalkal, Nivedita Priyadarshini, Ashutosh Kumar and Kuldeep Mahato

Micromachines 2023, 14(9), 1744; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14091744 - 07 Sep 2023

Cited by 4 | Viewed by 1326

Abstract

The pandemic of COVID-19 and its widespread transmission have made us realize the importance of early, quick diagnostic tests for facilitating effective cure and management. The primary obstacles encountered were accurately distinguishing COVID-19 from other illnesses including the flu, common cold, etc. While [...] Read more.

The pandemic of COVID-19 and its widespread transmission have made us realize the importance of early, quick diagnostic tests for facilitating effective cure and management. The primary obstacles encountered were accurately distinguishing COVID-19 from other illnesses including the flu, common cold, etc. While the polymerase chain reaction technique is a robust technique for the determination of SARS-CoV-2 in patients of COVID-19, there arises a high demand for affordable, quick, user-friendly, and precise point-of-care (POC) diagnostic in therapeutic settings. The necessity for available tests with rapid outcomes spurred the advancement of POC tests that are characterized by speed, automation, and high precision and accuracy. Paper-based POC devices have gained increasing interest in recent years because of rapid, low-cost detection without requiring external instruments. At present, microfluidic paper-based analysis devices have garnered public attention and accelerated the development of such POCT for efficient multistep assays. In the current review, our focus will be on the fabrication of detection modules for SARS-CoV-2. Here, we have included a discussion on various strategies for the detection of viral moieties. The compilation of these strategies would offer comprehensive insight into the detection of the causative agent preparedness for future pandemics. We also provide a descriptive outline for paper-based diagnostic platforms, involving the determination mechanisms, as well as a commercial kit for COVID-19 as well as their outlook. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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29 pages, 1134 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Exhaled Biomarkers for Point-of-Care Diagnosis: Recent Advances and New Challenges in Breathomics

by Helga Kiss, Zoltán Örlős, Áron Gellért, Zsolt Megyesfalvi, Angéla Mikáczó, Anna Sárközi, Attila Vaskó, Zsuzsanna Miklós and Ildikó Horváth

Micromachines 2023, 14(2), 391; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14020391 - 04 Feb 2023

Cited by 8 | Viewed by 3233

Abstract

Cancers, chronic diseases and respiratory infections are major causes of mortality and present diagnostic and therapeutic challenges for health care. There is an unmet medical need for non-invasive, easy-to-use biomarkers for the early diagnosis, phenotyping, predicting and monitoring of the therapeutic responses of [...] Read more.

Cancers, chronic diseases and respiratory infections are major causes of mortality and present diagnostic and therapeutic challenges for health care. There is an unmet medical need for non-invasive, easy-to-use biomarkers for the early diagnosis, phenotyping, predicting and monitoring of the therapeutic responses of these disorders. Exhaled breath sampling is an attractive choice that has gained attention in recent years. Exhaled nitric oxide measurement used as a predictive biomarker of the response to anti-eosinophil therapy in severe asthma has paved the way for other exhaled breath biomarkers. Advances in laser and nanosensor technologies and spectrometry together with widespread use of algorithms and artificial intelligence have facilitated research on volatile organic compounds and artificial olfaction systems to develop new exhaled biomarkers. We aim to provide an overview of the recent advances in and challenges of exhaled biomarker measurements with an emphasis on the applicability of their measurement as a non-invasive, point-of-care diagnostic and monitoring tool. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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23 pages, 2054 KiB

Open AccessReview

Applications of Smart Material Sensors and Soft Electronics in Healthcare Wearables for Better User Compliance

by Arnab Ghosh, Sagnik Nag, Alyssa Gomes, Apurva Gosavi, Gauri Ghule, Aniket Kundu, Buddhadev Purohit and Rohit Srivastava

Micromachines 2023, 14(1), 121; https://0-doi-org.brum.beds.ac.uk/10.3390/mi14010121 - 31 Dec 2022

Cited by 5 | Viewed by 3576

Abstract

The need for innovation in the healthcare sector is essential to meet the demand of a rapidly growing population and the advent of progressive chronic ailments. Over the last decade, real-time monitoring of health conditions has been prioritized for accurate clinical diagnosis and [...] Read more.

The need for innovation in the healthcare sector is essential to meet the demand of a rapidly growing population and the advent of progressive chronic ailments. Over the last decade, real-time monitoring of health conditions has been prioritized for accurate clinical diagnosis and access to accelerated treatment options. Therefore, the demand for wearable biosensing modules for preventive and monitoring purposes has been increasing over the last decade. Application of machine learning, big data analysis, neural networks, and artificial intelligence for precision and various power-saving approaches are used to increase the reliability and acceptance of smart wearables. However, user compliance and ergonomics are key areas that need focus to make the wearables mainstream. Much can be achieved through the incorporation of smart materials and soft electronics. Though skin-friendly wearable devices have been highlighted recently for their multifunctional abilities, a detailed discussion on the integration of smart materials for higher user compliance is still missing. In this review, we have discussed the principles and applications of sustainable smart material sensors and soft electronics for better ergonomics and increased user compliance in various healthcare devices. Moreover, the importance of nanomaterials and nanotechnology is discussed in the development of smart wearables. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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36 pages, 6211 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Emerging Bioanalytical Devices and Platforms for Rapid Detection of Pathogens in Environmental Samples

by Lightson Ngashangva, Bahaa A. Hemdan, Mohamed Azab El-Liethy, Vinay Bachu, Shelley D. Minteer and Pranab Goswami

Micromachines 2022, 13(7), 1083; https://0-doi-org.brum.beds.ac.uk/10.3390/mi13071083 - 08 Jul 2022

Cited by 7 | Viewed by 3623

Abstract

The development of robust bioanalytical devices and biosensors for infectious pathogens is progressing well with the advent of new materials, concepts, and technology. The progress is also stepping towards developing high throughput screening technologies that can quickly identify, differentiate, and determine the concentration [...] Read more.

The development of robust bioanalytical devices and biosensors for infectious pathogens is progressing well with the advent of new materials, concepts, and technology. The progress is also stepping towards developing high throughput screening technologies that can quickly identify, differentiate, and determine the concentration of harmful pathogens, facilitating the decision-making process for their elimination and therapeutic interventions in large-scale operations. Recently, much effort has been focused on upgrading these analytical devices to an intelligent technological platform by integrating them with modern communication systems, such as the internet of things (IoT) and machine learning (ML), to expand their application horizon. This review outlines the recent development and applications of bioanalytical devices and biosensors to detect pathogenic microbes in environmental samples. First, the nature of the recent outbreaks of pathogenic microbes such as foodborne, waterborne, and airborne pathogens and microbial toxins are discussed to understand the severity of the problems. Next, the discussion focuses on the detection systems chronologically, starting with the conventional methods, advanced techniques, and emerging technologies, such as biosensors and other portable devices and detection platforms for pathogens. Finally, the progress on multiplex assays, wearable devices, and integration of smartphone technologies to facilitate pathogen detection systems for wider applications are highlighted. Full article

(This article belongs to the Special Issue Microfluidics and Biosensors for Point-of-Care Applications)

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