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1.
Sensors (Basel) ; 24(1)2023 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-38202993

RESUMEN

Per- and polyfluoroalkyl substances (PFAS) are a class of materials that have been widely used in the industrial production of a wide range of products. After decades of bioaccumulation in the environment, research has demonstrated that these compounds are toxic and potentially carcinogenic. Therefore, it is essential to map the extent of the problem to be able to remediate it properly in the next few decades. Current state-of-the-art detection platforms, however, are lab based and therefore too expensive and time-consuming for routine screening. Traditional biosensor tests based on, e.g., lateral flow assays may struggle with the low regulatory levels of PFAS (ng/mL), the complexity of environmental matrices and the presence of coexisting chemicals. Therefore, a lot of research effort has been directed towards the development of biomimetic receptors and their implementation into handheld, low-cost sensors. Numerous research groups have developed PFAS sensors based on molecularly imprinted polymers (MIPs), metal-organic frameworks (MOFs) or aptamers. In order to transform these research efforts into tangible devices and implement them into environmental applications, it is necessary to provide an overview of these research efforts. This review aims to provide this overview and critically compare several technologies to each other to provide a recommendation for the direction of future research efforts focused on the development of the next generation of biomimetic PFAS sensors.


Asunto(s)
Biomimética , Fluorocarburos , Humanos , Carcinogénesis , Carcinógenos , Industrias
2.
J Chem Educ ; 98(2): 439-444, 2021 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-33583951

RESUMEN

The need to develop interest in STEM (science, technology, engineering, and mathematics) skills in young pupils has driven many educational systems to include STEM as a subject in primary schools. In this work, a science kit aimed at children from 8 to 14 years old is presented as a support platform for an innovative and stimulating approach to STEM learning. The peculiar design of the kit, based on modular components, is aimed to help develop a multitude of skills in the young students, dividing the learning process into two phases. During phase 1 the pupils build the experimental setup and visualize the scientific phenomena, while in phase 2, they are introduced and challenged to understand the principles on which these phenomena are based, guided by a handbook. This approach aims at making the experience more inclusive, stimulating the interest and passion of the pupils for scientific subjects.

3.
Sens Actuators B Chem ; 325: 128973, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-33012991

RESUMEN

Molecularly imprinted polymers (MIPs) have emerged over the past few decades as interesting synthetic alternatives due to their long-term chemical and physical stability and low-cost synthesis procedure. They have been integrated into many sensing platforms and assay formats for the detection of various targets, ranging from small molecules to macromolecular entities such as pathogens and whole cells. Despite the advantages MIPs have over natural receptors in terms of commercialization, the striking success stories of biosensor applications such as the glucose meter or the self-test for pregnancy have not been matched by MIP-based sensor or detection kits yet. In this review, we zoom in on the commercial potential of MIP technology and aim to summarize the latest developments in their commercialization and integration into sensors and assays with high commercial potential. We will also analyze which bottlenecks are inflicting with commercialization and how recent advances in commercial MIP synthesis could overcome these obstacles in order for MIPs to truly achieve their commercial potential in the near future.

4.
Molecules ; 25(22)2020 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-33182534

RESUMEN

The rapid sensing of drug compounds has traditionally relied on antibodies, enzymes and electrochemical reactions. These technologies can frequently produce false positives/negatives and require specific conditions to operate. Akin to antibodies, molecularly imprinted polymers (MIPs) are a more robust synthetic alternative with the ability to bind a target molecule with an affinity comparable to that of its natural counterparts. With this in mind, the research presented in this article introduces a facile MIP-based dye displacement assay for the detection of (±) amphetamine in urine. The selective nature of MIPs coupled with a displaceable dye enables the resulting low-cost assay to rapidly produce a clear visual confirmation of a target's presence, offering huge commercial potential. The following manuscript characterizes the proposed assay, drawing attention to various facets of the sensor design and optimization. To this end, synthesis of a MIP tailored towards amphetamine is described, scrutinizing the composition and selectivity (ibuprofen, naproxen, 2-methoxphenidine, quetiapine) of the reported synthetic receptor. Dye selection for the development of the displacement assay follows, proceeded by optimization of the displacement process by investigating the time taken and the amount of MIP powder required for optimum displacement. An optimized dose-response curve is then presented, introducing (±) amphetamine hydrochloride (0.01-1 mg mL-1) to the engineered sensor and determining the limit of detection (LoD). The research culminates in the assay being used for the analysis of spiked urine samples (amphetamine, ibuprofen, naproxen, 2-methoxphenidine, quetiapine, bupropion, pheniramine, bromopheniramine) and evaluating its potential as a low-cost, rapid and selective method of analysis.


Asunto(s)
Anfetaminas/orina , Colorantes/química , Polímeros Impresos Molecularmente , Polímeros/química , Detección de Abuso de Sustancias/métodos , Orina/química , Anfetamina/orina , Bromofeniramina/orina , Bupropión/orina , Relación Dosis-Respuesta a Droga , Técnicas Electroquímicas , Reacciones Falso Positivas , Humanos , Ibuprofeno/orina , Límite de Detección , Impresión Molecular , Naproxeno/orina , Feniramina/orina , Piperidinas/orina , Polvos , Fumarato de Quetiapina/orina
5.
Sensors (Basel) ; 19(5)2019 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-30857285

RESUMEN

The accurate detection of biological materials has remained at the forefront of scientific research for decades. This includes the detection of molecules, proteins, and bacteria. Biomimetic sensors look to replicate the sensitive and selective mechanisms that are found in biological systems and incorporate these properties into functional sensing platforms. Molecularly imprinted polymers (MIPs) are synthetic receptors that can form high affinity binding sites complementary to the specific analyte of interest. They utilise the shape, size, and functionality to produce sensitive and selective recognition of target analytes. One route of synthesizing MIPs is through electropolymerization, utilising predominantly constant potential methods or cyclic voltammetry. This methodology allows for the formation of a polymer directly onto the surface of a transducer. The thickness, morphology, and topography of the films can be manipulated specifically for each template. Recently, numerous reviews have been published in the production and sensing applications of MIPs; however, there are few reports on the use of electrosynthesized MIPs (eMIPs). The number of publications and citations utilising eMIPs is increasing each year, with a review produced on the topic in 2012. This review will primarily focus on advancements from 2012 in the use of eMIPs in sensing platforms for the detection of biologically relevant materials, including the development of increased polymer layer dimensions for whole bacteria detection and the use of mixed monomer compositions to increase selectivity toward analytes.


Asunto(s)
Técnicas Biosensibles/métodos , Impresión Molecular/métodos , Polímeros/química , Proteínas/análisis
6.
Sensors (Basel) ; 17(12)2017 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-29168733

RESUMEN

Serotonin is an important neurotransmitter that plays a major role in the pathogenesis of a variety of conditions, including psychiatric disorders. The detection of serotonin typically relies on high-performance liquid chromatography (HPLC), an expensive technique that requires sophisticated equipment and trained personnel, and is not suitable for point-of-care applications. In this contribution, we introduce a novel sensor platform that can measure spiked neurotransmitter concentrations in whole blood samples in a fast and low-cost manner by combining synthetic receptors with a thermal readout technique-the heat-transfer method. In addition, the design of a miniaturized version of the sensing platform is presented that aims to bridge the gap between measurements in a laboratory setting and point-of-care measurements. This fully automated and integrated, user-friendly design features a capillary pumping unit that is compatible with point-of-care sampling techniques such as a blood lancet device (sample volume-between 50 µL and 300 µL). Sample pre-treatment is limited to the addition of an anti-coagulant. With this fully integrated setup, it is possible to successfully discriminate serotonin from a competitor neurotransmitter (histamine) in whole blood samples. This is the first demonstration of a point-of-care ready device based on synthetic receptors for the screening of neurotransmitters in complex matrices, illustrating the sensor's potential application in clinical research and diagnosis of e.g., early stage depression.

7.
Molecules ; 21(5)2016 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-27128891

RESUMEN

A novel procedure is developed for producing bulk modified Molecularly Imprinted Polymer (MIP) screen-printed electrodes (SPEs), which involves the direct mixing of the polymer particles within the screen-printed ink. This allowed reduction of the sample preparation time from 45 min to 1 min, and resulted in higher reproducibility of the electrodes. The samples are measured with a novel detection method, namely, thermal wave transport analysis (TWTA), relying on the analysis of thermal waves through a functional interface. As a first proof-of-principle, MIPs for dopamine are developed and successfully incorporated within a bulk modified MIP SPE. The detection limits of dopamine within buffer solutions for the MIP SPEs are determined via three independent techniques. With cyclic voltammetry this was determined to be 4.7 × 10(-6) M, whereas by using the heat-transfer method (HTM) 0.35 × 10(-6) M was obtained, and with the novel TWTA concept 0.26 × 10(-6) M is possible. This TWTA technique is measured simultaneously with HTM and has the benefits of reducing measurement time to less than 5 min and increasing effect size by nearly a factor of two. The two thermal methods are able to enhance dopamine detection by one order of magnitude compared to the electrochemical method. In previous research, it was not possible to measure neurotransmitters in complex samples with HTM, but with the improved signal-to-noise of TWTA for the first time, spiked dopamine concentrations were determined in a relevant food sample. In summary, novel concepts are presented for both the sensor functionalization side by employing screen-printing technology, and on the sensing side, the novel TWTA thermal technique is reported. The developed bio-sensing platform is cost-effective and suitable for mass-production due to the nature of screen-printing technology, which makes it very interesting for neurotransmitter detection in clinical diagnostic applications.


Asunto(s)
Dopamina/análisis , Impresión Molecular/métodos , Polímeros/química , Técnicas Electroquímicas , Electrodos , Peso Molecular , Conductividad Térmica
8.
Langmuir ; 31(6): 2043-50, 2015 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-25654744

RESUMEN

Previous work has indicated that surface imprinted polymers (SIPs) allow for highly specific cell detection through macromolecular cell imprints. The combination of SIPs with a heat-transfer-based read-out technique has led to the development of a selective, label-free, low-cost, and user-friendly cell detection assay. In this study, the breast cancer cell line ZR-75-1 is used to assess the potential of the platform for monitoring the quality of a cell culture in time. For this purpose, we show that the proposed methodology is able to discriminate between the original cell line (adherent growth, ZR-75-1a) and a descendant cell line (suspension growth, ZR-75-1s). Moreover, ZR-75-1a cells were cultured for a prolonged period of time and analyzed using the heat-transfer method (HTM) at regular time intervals. The results of these experiments demonstrate that the thermal resistance (Rth) signal decays after a certain number of cell culture passages. This can likely be attributed to a compromised quality of the cell culture due to cross-contamination with the ZR-75-1s cell line, a finding that was confirmed by classical STR DNA profiling. The cells do not express the same functional groups on their membrane, resulting in a weaker bond between cell and imprint, enabling cell removal by mechanical friction, provided by flushing the measuring chamber with buffer solution. These findings were further confirmed by HTM and illustrate that the biomimetic sensor platform can be used as an assay for monitoring the quality of cell cultures in time.


Asunto(s)
Biomimética/métodos , Calor , Impresión Molecular , Sondas Moleculares/síntesis química , Polímeros/síntesis química , Técnicas de Cultivo de Célula , Línea Celular Tumoral , Humanos , Repeticiones de Microsatélite , Sondas Moleculares/metabolismo , Polímeros/metabolismo , Control de Calidad , Propiedades de Superficie
9.
ACS Omega ; 9(22): 23155-23171, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38854523

RESUMEN

Ensuring a rapid and accurate identification of harmful bacteria is crucial in various fields including environmental monitoring, food safety, and clinical diagnostics. Conventional detection methods often suffer from limitations such as long analysis time, complexity, and the need for qualified personnel. Therefore, a lot of research effort is devoted to developing technologies with the potential to revolutionize the detection of pathogenic bacteria by offering rapid, sensitive, and user-friendly platforms for point-of-care analysis. In this light, biosensors have gained significant commercial attention in recent years due to their simplicity, portability, and rapid analysis capabilities. The purpose of this review is to identify a trend by analyzing which biosensor technologies have become commercially successful in the field of bacteria detection. Moreover, we highlight the characteristics that a biosensor must possess to finally arrive in the market and therefore in the hands of the end-user, and we present critical examples of the market applications of various technologies. The aim is to investigate the reason why certain technologies have achieved commercial success and extrapolate these trends to the future economic viability of a new subfield in the world of biosensing: the development of biomimetic sensor platforms. Therefore, an overview of recent advances in the field of biomimetic bacteria detection will be presented, after which the challenges that need to be addressed in the coming years to improve market penetration will be critically evaluated. We will zoom into the current shortcomings of biomimetic sensors based on imprinting technology and aptamers and try to come up with a recommendation for further development based on the trends observed from previous commercial success stories in biosensing.

10.
ACS Sens ; 8(1): 353-362, 2023 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-36599088

RESUMEN

Pseudomonas aeruginosa is a ubiquitous multi-drug-resistant bacterium, capable of causing serious illnesses and infections. This research focuses on the development of a thermal sensor for the indirect detection of P. aeruginosa infection using molecularly imprinted polymers (MIPs). This was achieved by developing MIPs for the detection of pyocyanin, the main toxin secreted by P. aeruginosa. To this end, phenazine was used as a dummy template, evaluating several polymeric compositions to achieve a selective MIP for pyocyanin recognition. The sensitivity of the synthesized MIPs was investigated by UV-vis analysis, with the best composition having a maximum rebinding capacity of 30 µmol g-1 and an imprinting factor (IF) of 1.59. Subsequently, the MIP particles were immobilized onto planar aluminum chips using an adhesive layer, to perform thermal resistance measurements at clinically relevant concentrations of pyocyanin (1.4-9.8 µM), achieving a limit of detection (LoD) of 0.347 ± 0.027 µM. The selectivity of the sensor was also scrutinized by subjecting the receptor to potential interferents. Furthermore, the rebinding was demonstrated in King's A medium, highlighting the potential of the sensor for the indirect detection of P. aeruginosa in complex fluids. The research culminates in the demonstration of the MIP-based sensor's applicability for clinical diagnosis. To achieve this goal, an experiment was performed in which the sensor was exposed to pyocyanin-spiked saliva samples, achieving a limit of detection of 0.569 ± 0.063 µM and demonstrating that this technology is suitable to detect the presence of the toxin even at the very first stage of its production.


Asunto(s)
Impresión Molecular , Polímeros Impresos Molecularmente , Pseudomonas aeruginosa , Piocianina , Técnicas Electroquímicas
11.
EJNMMI Res ; 13(1): 42, 2023 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-37171631

RESUMEN

By clearing GABA from the synaptic cleft, GABA transporters (GATs) play an essential role in inhibitory neurotransmission. Consequently, in vivo visualization of GATs can be a valuable diagnostic tool and biomarker for various psychiatric and neurological disorders. Not surprisingly, in recent years several research attempts to develop a radioligand have been conducted, but so far none have led to suitable radioligands that allow imaging of GATs. Here, we provide an overview of the radioligands that were developed with a focus on GAT1, since this is the most abundant transporter and most of the research concerns this GAT subtype. Initially, we focus on the field of GAT1 inhibitors, after which we discuss the development of GAT1 radioligands based on these inhibitors. We hypothesize that the radioligands developed so far have been unsuccessful due to the zwitterionic nature of their nipecotic acid moiety. To overcome this problem, the use of non-classical GAT inhibitors as basis for GAT1 radioligands or the use of carboxylic acid bioisosteres may be considered. As the latter structural modification has already been used in the field of GAT1 inhibitors, this option seems particularly viable and could lead to the development of more successful GAT1 radioligands in the future.

12.
Food Chem ; 404(Pt B): 134653, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36327513

RESUMEN

Accurate and fast on-site detection of harmful microorganisms in food products is a key preventive step to avoid food-borne illness and product recall. In this study, screen-printed electrodes (SPEs) were functionalized via a facile strategy with surface imprinted polymers (SIPs). The SIP-coated SPEs were used in combination with the heat transfer method (HTM) for the real-time detection of Escherichia coli. The sensor was tested in buffer, with a reproducible and sensitive response that attained a limit of detection of 180 CFU/mL. Furthermore, selectivity was assessed by analyzing the sensor's response to C. sakazakii, K. pneumoniae and S. aureus as analogue strains. Finally, the device was successfully used for the detection of E. coli in spiked milk as proof-of-application, requiring no additional sample preparation. These results suggest the proposed thermal biosensor possesses the potential of becoming a tool for routine, on-site monitoring of E. coli in food safety applications.


Asunto(s)
Técnicas Biosensibles , Escherichia coli , Staphylococcus aureus , Electrodos , Técnicas Biosensibles/métodos , Productos Lácteos , Límite de Detección
13.
Biomacromolecules ; 13(5): 1448-57, 2012 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-22515272

RESUMEN

Three-dimensional cell culture and conditioning is an effective means to guide cell distribution and patterning for tissue engineered constructs such as vascular grafts. Polyacrylic acid is known as an electroresponsive polymer, capable of transforming environmental stimuli like electrical energy to mechanical forces. In this study, we developed an electrosensitive and biocompatible hydrogel-based smart device composed of acrylic acid and fibrin as a tissue engineered construct to mechanically stimulate cells. Structural properties of the hydrogel were assessed by FTIR-ATR, scanning electron microscopy, prosimetry, and swelling measurement. Distribution and alignment of porcine smooth muscle cells (pSMCs) seeded on the surface of lyophilized hydrogels were evaluated and quantified by two-photon laser scanning microscopy. Smooth muscle cell tissue constructs exposed to 2 h of pulsatile electrical stimulation showed significantly enhanced cell penetration and alignment due to dynamic changes produced by alternative swelling and deswelling, in comparison with static samples. On the basis of the results, this hydrogel under electrical stimulation works as a mechanical pump, which can direct SMC alignment and facilitate infiltration and distribution of cells throughout the structure.


Asunto(s)
Resinas Acrílicas/química , Estimulación Eléctrica , Fibrina/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Animales , Materiales Biocompatibles/química , Adhesión Celular , Supervivencia Celular , Células Cultivadas , Miocitos del Músculo Liso/citología , Porcinos , Ingeniería de Tejidos
14.
ACS Sens ; 7(5): 1467-1475, 2022 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-35537189

RESUMEN

This work presents an imprinted polymer-based thermal biomimetic sensor for the detection of Escherichia coli. A novel and facile bacteria imprinting protocol for polydimethylsiloxane (PDMS) films was investigated, and these receptor layers were functionalized with graphene oxide (GO) in order to improve the overall sensitivity of the sensor. Upon the recognition and binding of the target to the densely imprinted polymers, a concentration-dependent measurable change in temperature was observed. The limit of detection attained for the sensor employing PDMS-GO imprints was 80 ± 10 CFU/mL, a full order lower than neat PDMS imprints (670 ± 140 CFU/mL), illustrating the beneficial effect of the dopant on the thermo-dynamical properties of the interfacial layer. A parallel benchmarking of the thermal sensor with a commercial impedance analyzer was performed in order to prove the possibility of using the developed PDMS-GO receptors with multiple readout platforms. Moreover, S. aureus, C. sakazakii and an additional E. coli strain were employed as analogue species for the assessment of the selectivity of the device. Finally, because of the potential that this biomimetic platform possesses as a low-cost, rapid, and on-site tool for monitoring E. coli contamination in food safety applications, spiked fruit juice was analyzed as a real sample. Reproducible and sensitive results fulfill the limit requirements of the applicable European microbiological regulation.


Asunto(s)
Impresión Molecular , Biomimética , Dimetilpolisiloxanos , Escherichia coli , Grafito , Impresión Molecular/métodos , Polímeros/química , Staphylococcus aureus
15.
Foods ; 11(18)2022 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-36141032

RESUMEN

In recent years, melamine-sensing technologies have increasingly gained attention, mainly due to the misuse of the molecule as an adulterant in milk and other foods. Molecularly imprinted polymers (MIPs) are ideal candidates for the recognition of melamine in real-life samples. The prepared MIP particles were incorporated into a thermally conductive layer via micro-contact deposition and its response towards melamine was analyzed using the heat-transfer method (HTM). The sensor displayed an excellent selectivity when analyzing the thermal response to other chemicals commonly found in foods, and its applicability in food safety was demonstrated after evaluation in untreated milk samples, demonstrating a limit of detection of 6.02 µM. As the EU/US melamine legal limit in milk of 2.5 mg/kg falls within the linear range of the sensor, it can offer an innovative solution for routine screening of milk samples in order to detect adulteration with melamine. The results shown in this work thus demonstrate the great potential of a low-cost thermal platform for the detection of food adulteration in complex matrices.

16.
Polymers (Basel) ; 13(13)2021 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-34279364

RESUMEN

The scope of the presented research orientates itself towards the development of a Molecularly Imprinted Polymer (MIP)-based dye displacement assay for the colorimetric detection of the antibiotic amoxicillin in aqueous medium. With this in mind, the initial development of an MIP capable of such a task sets focus on monolithic bulk polymerization to assess monomer/crosslinker combinations that have potential towards the binding of amoxicillin. The best performing composition (based on specificity and binding capacity) is utilized in the synthesis of MIP particles by emulsion polymerization, yielding particles that prove to be more homogenous in size and morphology compared to that of the crushed monolithic MIP, which is an essential trait when it comes to the accuracy of the resulting assay. The specificity and selectivity of the emulsion MIP proceeds to be highlighted, demonstrating a higher affinity towards amoxicillin compared to other compounds of the aminopenicillin class (ampicillin and cloxacillin). Conversion of the polymeric receptor is then undertaken, identifying a suitable dye for the displacement assay by means of binding experiments with malachite green, crystal violet, and mordant orange. Once identified, the optimal dye is then loaded onto the synthetic receptor, and the displaceability of the dye deduced by means of a dose response experiment. Alongside the sensitivity, the selectivity of the assay is scrutinized against cloxacillin and ampicillin. Yielding a dye displacement assay that can be used (semi-)quantitatively in a rapid manner.

17.
Biosensors (Basel) ; 11(2)2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33670184

RESUMEN

Foodborne illnesses represent high costs worldwide in terms of medical care and productivity. To ensure safety along the food chain, technologies that help to monitor and improve food preservation have emerged in a multidisciplinary context. These technologies focus on the detection and/or removal of either biological (e.g., bacteria, virus, etc.) or chemical (e.g., drugs and pesticides) safety hazards. Imprinted polymers are synthetic receptors able of recognizing both chemical and biological contaminants. While numerous reviews have focused on the use of these robust materials in extraction and separation applications, little bibliography summarizes the research that has been performed on their coupling to sensing platforms for food safety. The aim of this work is therefore to fill this gap and highlight the multidisciplinary aspects involved in the application of imprinting technology in the whole value chain ranging from IP preparation to integrated sensor systems for the specific recognition and quantification of chemical and microbiological contaminants in food samples.


Asunto(s)
Impresión Molecular , Polímeros , Inocuidad de los Alimentos , Plaguicidas , Receptores Artificiales
18.
Biosensors (Basel) ; 11(10)2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34677351

RESUMEN

We demonstrate a novel way of creating three-dimensional microfluidic channels capable of following complex topographies. To this end, substrates with open channels and different geometries were 3D-printed, and the open channels were consecutively closed with a thermoplastic using a low-resolution vacuum-forming approach. This process allows the sealing of channels that are located on the surface of complex multiplanar topographies, as the thermoplastic aligns with the surface-shape (the macrostructure) of the substrate, while the microchannels remain mostly free of thermoplastic as their small channel size resists thermoplastic inflow. This new process was analyzed for its capability to consistently close different substrate geometries, which showed reliable sealing of angles >90°. Furthermore, the thermoplastic intrusion into channels of different widths was quantified, showing a linear effect of channel width and percentage of thermoplastic intrusion; ranging from 43.76% for large channels with 2 mm width to only 5.33% for channels with 500 µm channel width. The challenging sealing of substrate 'valleys', which are created when two large protrusions are adjacent to each other, was investigated and the correlation between protrusion distance and height is shown. Lastly, we present three application examples: a serpentine mixer with channels spun around a cuboid, increasing the usable surface area; a cuvette-inspired flow cell for a 2-MXP biosensor based on molecular imprinted polymers, fitting inside a standard UV/Vis-Spectrophotometer; and an adapter system that can be manufactured by one-sided injection molding and is self-sealed before usage. These examples demonstrate how this novel technology can be used to easily adapt microfluidic circuits for application in biosensor platforms.


Asunto(s)
Microfluídica , Terapia de Presión Negativa para Heridas , Polímeros , Impresión Tridimensional
19.
ACS Sens ; 6(12): 4515-4525, 2021 12 24.
Artículo en Inglés | MEDLINE | ID: mdl-34825565

RESUMEN

Glucose bio-sensing technologies have received increasing attention in the last few decades, primarily due to the fundamental role that glucose metabolism plays in diseases (e.g., diabetes). Molecularly imprinted polymers (MIPs) could offer an alternative means of analysis to a field that is traditionally dominated by enzyme-based devices, posing superior chemical stability, cost-effectiveness, and ease of fabrication. Their integration into sensing devices as recognition elements has been extensively studied with different readout methods such as quartz-crystal microbalance or impedance spectroscopy. In this work, a dummy imprinting approach is introduced, describing the synthesis and optimization of a MIP toward the sensing of glucose. Integration of this polymer into a thermally conductive receptor layer was achieved by micro-contact deposition. In essence, the MIP particles are pressed into a polyvinyl chloride adhesive layer using a polydimethylsiloxane stamp. The prepared layer is then evaluated with the so-called heat-transfer method, allowing the determination of the specificity and the sensitivity of the receptor layer. Furthermore, the selectivity was assessed by analyzing the thermal response after infusion with increasing concentrations of different saccharide analogues in phosphate-buffered saline (PBS). The obtained results show a linear range of the sensor of 0.0194-0.3300 mM for the detection of glucose in PBS. Finally, a potential application of the sensor was demonstrated by exposing the receptor layer to increasing concentrations of glucose in human urine samples, demonstrating a linear range of 0.0444-0.3300 mM. The results obtained in this paper highlight the applicability of the sensor both in terms of non-invasive glucose monitoring and for the analysis of food samples.


Asunto(s)
Impresión Molecular , Glucemia , Automonitorización de la Glucosa Sanguínea , Glucosa , Humanos , Polímeros Impresos Molecularmente
20.
J Org Chem ; 75(21): 7202-9, 2010 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-20925367

RESUMEN

A convenient and efficient three-step route toward both symmetrically and asymmetrically functionalized 4H-cyclopenta[2,1-b:3,4-b']dithiophenes has been developed. Using this method a broad collection of functionalized bridged bithiophenes can smoothly be accessed. Starting from 3-bromo-2,2'-bithiophene, prepared by Kumada coupling of 2-thienylmagnesium bromide with 2,3-dibromothiophene under Pd(dppf)Cl(2) catalysis, lithiation and subsequent reaction with dialkyl ketones afforded (a)symmetrically dialkylated tertiary alcohol derivatives. By means of final Friedel-Crafts dehydration cyclization in sulfuric acid medium, these derivatives were converted to 4,4-dialkyl-4H-cyclopenta[2,1-b:3,4-b']dithiophenes. Upon replacement of the dialkyl ketone reagent by ethyl levulinate, an ester-functionalized 4H-cyclopenta[2,1-b:3,4-b']dithiophene was prepared, representing an attractive precursor for variously functionalized cyclopentadithiophene compounds.

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