Rapid and sensitive point-of-care diagnostics are of paramount importance for early detection of infectious diseases and timely initiation of treatment. Here, we present cellulose paper and flexible ...plastic chips with printed graphene-modified silver electrodes as universal point-of-care diagnostic tools for the rapid and sensitive detection of microbial pathogens or nucleic acids through utilizing electrical sensing modality and loop-mediated isothermal amplification (LAMP). We evaluated the ability of the developed paper-based assay to detect (i) viruses on cellulose-based paper microchips without implementing amplification in samples with viral loads between 10
and 10
copies per ml, and (ii) amplified HIV-1 nucleic acids in samples with viral loads between 10 fg μl
and 10
fg μl
. The target HIV-1 nucleic acid was amplified using the RT-LAMP technique and detected through the electrical sensing of LAMP amplicons for a broad range of RNA concentrations between 10 fg μl
and 10
fg μl
after 40 min of amplification time. Our assay may be used for antiretroviral therapy monitoring where it meets the sensitivity requirement of the World Health Organization guidelines. Such a paper microchip assay without the amplification step may also be considered as a simple and inexpensive approach for acute HIV detection where maximum viral replication occurs.
The widespread accessibility of commercial/clinically‐viable electrochemical diagnostic systems for rapid quantification of viral proteins demands translational/preclinical investigations. Here, ...Covid‐Sense (CoVSense) antigen testing platform; an all‐in‐one electrochemical nano‐immunosensor for sample‐to‐result, self‐validated, and accurate quantification of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) nucleocapsid (N)‐proteins in clinical examinations is developed. The platform's sensing strips benefit from a highly‐sensitive, nanostructured surface, created through the incorporation of carboxyl‐functionalized graphene nanosheets, and poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) conductive polymers, enhancing the overall conductivity of the system. The nanoengineered surface chemistry allows for compatible direct assembly of bioreceptor molecules. CoVSense offers an inexpensive (<$2 kit) and fast/digital response (<10 min), measured using a customized hand‐held reader (<$25), enabling data‐driven outbreak management. The sensor shows 95% clinical sensitivity and 100% specificity (Ct<25), and overall sensitivity of 91% for combined symptomatic/asymptomatic cohort with wildtype SARS‐CoV‐2 or B.1.1.7 variant (N = 105, nasal/throat samples). The sensor correlates the N‐protein levels to viral load, detecting high Ct values of ≈35, with no sample preparation steps, while outperforming the commercial rapid antigen tests. The current translational technology fills the gap in the workflow of rapid, point‐of‐care, and accurate diagnosis of COVID‐19.
Covid‐Sense
(CoVSense) utilizes electrochemical immunosensing technology for rapid and quantitative detection of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) viruses in clinical nasal specimens obtained from all‐inclusive cohort of patients, offering favorable features in terms of accuracy, signal correlation with viral load, and digital data management, compared to gold standard techniques, such as polymerase chain reaction and lateral flow strips.
•UV-triggered polymerization of catecholamine materials forming polydopamine and polynorepinephrine to implement organ-on-a-chip (OOC).•UV-light of a standard biosafety cabinet utilized for the ...polymerization of PDMS substrates.•Three different types of OOCs created using this technique:(i)Plasma-bonded, polymer-coated chips,(ii)UV-bonded, polymer-coated chips,(iii)projection coated fluid wall chips.•The UV-light and the catecholamine material together offer a simple yet effective technique for implementing OOC.
Surface modification of microfluidic chips used for making organ-on-a-chip (OOC) applications is often a time-consuming process, involving chip cleaning, ultraviolet (UV)-exposure, and steam sterilization. This work reports developing a simple, rapid, and cost-effective method that can achieve photo-activated polymerization and patterning of catecholamine materials on microfluidic chips in a single step using the UV light present in a standard biosafety cabinet. Polydimethylsiloxane (PDMS) microfluidic devices were filled with monomers of dopamine and norepinephrine, followed by exposure to UV light triggers polymerization of the material, which creates a highly viable surface for OOC applications. We examined the performance of these UV-triggered surface coatings for creating three different kinds of OOCs, where microfluidic chips were bonded and modified in three different ways: i) conventional oxygen plasma bonded microfluidic chips filled with monomer solutions and then exposed to UV to modify the surface (Plasma bonded, polymer-coated); ii) both the fluidic layer and glass substrate were exposed to UV to coat the functional layer and simultaneously allow adhesive proteins to bind the two pieces together (UV-bonded, polymer-coated); and iii) project the UV light through a mask to create fluid wall microfluidic channels on a polydimethylsiloxane (PDMS) substrate (projection coating). Cath.a.differentiated (CAD) cells seeded on UV-exposed polymer-coated surface in the three techniques showed significantly high cell viability, cell adhesion, proliferation, genetic expression, and they retained the functionality compared to uncoated PDMS. The UV-triggered surface modification technique uses a minimalist approach by using less equipment and existing infrastructure, such as a biosafety cabinet, for creating a functional OOC. This novel, simple, low-cost approach to reproducibly generating an organ-on-a-chip will facilitate the wider adoption of this technique.
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Hydrogels have been recognized as crucial biomaterials in the field of tissue engineering, regenerative medicine, and drug delivery applications due to their specific characteristics. ...These biomaterials benefit from retaining a large amount of water, effective mass transfer, similarity to natural tissues and the ability to form different shapes. However, having relatively poor mechanical properties is a limiting factor associated with hydrogel biomaterials. Controlling the biomechanical properties of hydrogels is of paramount importance. In this work, firstly, mechanical characteristics of hydrogels and methods employed for characterizing these properties are explored. Subsequently, the most common approaches used for tuning mechanical properties of hydrogels including but are not limited to, interpenetrating polymer networks, nanocomposites, self-assembly techniques, and co-polymerization are discussed. The performance of different techniques used for tuning biomechanical properties of hydrogels is further compared. Such techniques involve lithography techniques for replication of tissues with complex mechanical profiles; microfluidic techniques applicable for generating gradients of mechanical properties in hydrogel biomaterials for engineering complex human tissues like intervertebral discs, osteochondral tissues, blood vessels and skin layers; and electrospinning techniques for synthesis of hybrid hydrogels and highly ordered fibers with tunable mechanical and biological properties. We finally discuss future perspectives and challenges for controlling biomimetic hydrogel materials possessing proper biomechanical properties.
Hydrogels biomaterials are essential constituting components of engineered tissues with the applications in regenerative medicine and drug delivery. The mechanical properties of hydrogels play crucial roles in regulating the interactions between cells and extracellular matrix and directing the cells phenotype and genotype. Despite significant advances in developing methods and techniques with the ability of tuning the biomechanical properties of hydrogels, there are still challenges regarding the synthesis of hydrogels with complex mechanical profiles as well as limitations in vascularization and patterning of complex structures of natural tissues which barricade the production of sophisticated organs. Therefore, in addition to a review on advanced methods and techniques for measuring a variety of different biomechanical characteristics of hydrogels, the new techniques for enhancing the biomechanics of hydrogels are presented. It is expected that this review will profit future works for regulating the biomechanical properties of hydrogel biomaterials to satisfy the demands of a variety of different human tissues.
Isolation of circulating tumor cells (CTCs) from blood has long been a challenge due to the rarity and heterogeneity of these cells. Detection technologies have predominantly focused on different ...molecular or physical properties of CTCs. Size‐based isolation approach using microfilters have been widely used to capture CTCs because of the difference in size and stiffness of the cells compared to other hemocytes. Isolation of rare cells based on their size was the original CTC enrichment technique and it demonstrated a simple yet rapid method that enhanced the recovery of cells with high throughput. In this review, we highlight key technical aspects of filter‐based isolation, detection, and characterization of CTCs, and compare the clinical performance of filter‐based devices with the approved platforms and immunoassays used for the analysis of CTCs. We have also discussed future prospective and incorporation of advances in immunochemistry technique into the filter‐based platforms for enhancing the utility in clinical settings.
Isolation of circulating tumor cells (CTCs) from blood has long been a challenge due to the rarity and heterogeneity of these cells. Detection technologies have predominantly focused on different molecular or physical properties of CTCs. Size‐based isolation approach using microfilters have been widely used to capture CTCs because of the difference in size and stiffness of the cells compared to other hemocytes.
Future point-of-care (PoC) and wearable electrochemical biosensors explore new technology solutions to eliminate the need for multistep electrode modification and functionalization, overcome the ...limited reproducibility, and automate the sensing steps. In this work, a new screen-printed immuno-biosensor strip is engineered and characterized using a hybrid graphene nanosheet intermixed with the conductive poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymers, all embedded within the base carbon matrix (GiPEC) of the screen-printing ink. This intermixed nanocomposite ink is chemically designed for self-containing the “carboxyl” functional groups as the most specific chemical moiety for protein immobilization on the electrodes. The GiPEC ink enables capturing the target antibodies on the electrode without any need for extra surface preparation. As a proof of concept, the performance of the non-functionalized ready-to-immobilize strips was assessed for the detection of glial fibrillary acidic protein (GFAP) as a known central nervous system injury blood biomarker. This immuno-biosensor exhibits the limit of detection of 281.7 fg mL–1 (3 signal-to-noise ratio) and the sensitivity of 322.6 Ω mL pg–1 mm–2 within the clinically relevant linear detection range from 1 pg mL–1 to 10 ng mL–1. To showcase its potential PoC application, the bio-ready strip is embedded inside a capillary microfluidic device and automates electrochemical quantification of GFAP spiked in phosphate-buffered saline and the human serum. This new electrochemical biosensing platform can be further adapted for the detection of various protein biomarkers with the application in realizing on-chip immunoassays.
Rapid, selective, and ultra-sensitive detection of brain and spinal cord injury markers in bodily fluids is an unmet clinical need. In this work, Polycatecholamine as a rich source of amine moieties ...was used for single-step fabrication of ultrasensitive immunosensors for the detection of Ubiquitin carboxyl-terminal hydrolase (UCHL-1) biomarker of brain and spinal cord injuries and address the clinical need. The surface of graphene electrodes was modified by electropolymerizing aqueous solution of dopamine (DA) and norepinephrine (NE) monomers for generating polycatecholamines nanofilms on the surface of graphene screen printed electrodes (GSPE) in a single functionalization step. Amine moieties of the polymer allowed immobilization of UCHL-1 antibody on the electrode. The single-step modification of GSPE offered a simple, ultrasensitive, and stable production of immunosensors for the detection of UCHL-1. The operational range of the UCHL-1 immunosensor developed with Polynorepinephrine pNE-modified is 0.1 pg mL−1 – 105 pg mL−1 (LOD: 1.91 pg mL−1), and 1 pg mL−1 – 105 pg mL−1 (LOD: 0.70 pg mL−1) with Polydopamine (pDA) modification, satisfying the clinical range. Both pNE and pDA modified immunosensors, detected UCHL-1 spiked in phosphate buffer saline, artificial cerebrospinal fluid, and serum. Along with the sensitive detections, selective performances were recorded in the above matrices in the presence of interfering neurotransmitters GABA and Glutamate as well as glial fibrillary acidic protein (GFAP). Upon testing clinical samples of spinal cord injury patients and healthy controls, both pNE and pDA immunosensors, delivered a comparable response for UCHL-1, thereby, making immunosensors useful for clinical settings.
•Single-step modification of graphene electrode with Polycatecholamine polymers.•Polynorepinephrine (pNE) and Polydopamine (pDA) nanofilms offered binding sites to UCHL-1 antibody.•Comparable performance of both the immunosensors against standard ELISA.•Ultra-sensitive detection of UCHL-1 in the blood samples of spinal cord injury patients.
Microfluidic technologies for anticancer drug studies Valente, Karolina P.; Khetani, Sultan; Kolahchi, Ahmad R. ...
Drug discovery today,
November 2017, 2017-11-00, 20171101, Letnik:
22, Številka:
11
Journal Article
Recenzirano
•3D cell systems show high resistance to cytotoxic treatment compared with 2D models.•Microfluidic systems allow cost-effective analysis of cytotoxic drugs.•Integration of multiple microfluidic ...systems can recreate physiological cell–cell interactions.•Microfluidic chips allow integration of chemical/biological sensors for real-time responses.
The study of cancer growth mechanisms and the determination of the efficacy of experimental therapeutics are usually performed in two-dimensional (2D) cell culture models. However, these models are incapable of mimicking complex interactions between cancer cells and the environment. With the advent of microfluidic technologies, the combination of multiple cell cultures with mechanical and biochemical stimuli has enabled a better recapitulation of the three-dimensional (3D) tumor environment using minute amounts of reagents. These models can also be used to study drug transport, hypoxia, and interstitial pressure within the tumor. In this review, we highlight the applications of microfluidic-based models in anticancer drug studies and provide a perspective on the future of the clinical applications of microfluidic systems for anticancer drug development.
Microfluidic technology offers an excellent alternative for current in vitro models. This review examines the impact of microfluidic systems on chemotherapeutic studies as a basis for diminishing the gap between in vivo and in vitro models.
•This paper present an electrochemical biosensor for label-free and direct detection of S100β.•S100β is known biomarker for the diagnosing and prognosticating of the spinal cord injury.•The sensor is ...sensitive and within the dynamic detection range of 1pg/ml–10ng/ml.•The biomarker of interest was detected in artificial CSF and human blood serum.
S100 calcium-binding protein β (S100β), a member of the S100 protein family, is one of the spinal cord injury (SCI) biomarkers extensively studied for its diagnostic and prognostic potential. The concentration of S100β is found to increase in the blood and cerebrospinal fluid (CSF) after SCI. Here, we developed an electrochemical immunosensor that offers label-free and direct detection of S100β to aid the diagnosis and prognosis of SCI. A screen-printed graphene electrode was modified by electrochemically reducing nitrate from 4-nitrobenenediazonium tetrafluoroborate to an amine group. The covalent conjugation of S100β monoclonal antibody was then achieved on the electrode surface by activating the amine group using glutaraldehyde. Characterization of the electrode was implemented using differential pulse voltammetry (DPV) in presence of potassium ferricyanide (K3Fe(CN)6) redox probe. Upon testing the samples on the modified electrode with different concentrations of S100β, the DPV current peak decreased with the increase in concentration of S100β biomarker. We achieved sensitive and selective label-free detection of S100β in the dynamic range of 1pg/ml–104pg/ml for samples prepared in phosphate buffer saline (PBS), artificial CSF (aCSF), and human blood serum. The performance of the immunosensor was validated by correlating the results for samples tested with commercially available enzyme-linked immunosorbent assay (ELISA) method.
The conceptualization of body-on-a-chip in 2004 resulted in a new approach for studying human physiology in three-dimensional culture. Despite pioneering works and the progress made in replicating ...human physiology on-a-chip, the stability, reliability, and preservation of cell-culture-treated microfluidic chips remain a challenge. The development of a reliable surface treatment technique to more efficiently and reproducibly modify microfluidic channels would significantly simplify the process of creating and implementing organ-on-a-chip (OOC) systems. In this work, a new flow-based coating technique using bioinspired polymers was implemented to create reliable, reproducible, ready-to-use microfluidic cell culture chips for OOC studies. Single-channel polydimethylsiloxane microfluidic chips were coated with the bioinspired catecholamine polymers, polydopamine (PDA) and polynorepinephrine (PNE), using a flow-based coating technique. The functionality of the resulting microfluidic chips was evaluated by extensive surface characterizations, at 130 °C, in the presence of various cleaning and culture media in static and flow conditions regularly used in OOCs and tested for shelf life by storing the coated microfluidic chips for 4 months at room temperature. Microfluidic chips coated with polycatecholamine were then seeded with the mouse cancer cell line Cath.a.differentiated (CAD) and with the normal human cerebral microvascular endothelial cell line human cerebral microvascular endothelial cells (hCMEC)/D3. Cell viability, cell phenotype, and cell functionality were assessed to evaluate the performance of both the coatings and the surface treatment technique. Both PDA- and PNE-coated microfluidic chips maintained high viability, phenotype, and functionality of CAD cells and hCMEC/D3 cells. In addition, CAD cells retained high viability when they were cultured in both the polymer-coated chips, which were stored at room temperature for up to 120 days. These results suggest that flow-based techniques to coat surfaces with polycatecholamines can be used to generate ready-to-use microfluidic OOC chips that offer long-term stability and reliability for the culture of cell types with application in pathophysiological studies and drug screening.
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