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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 324: 124972, 2025 Jan 05.
Article in English | MEDLINE | ID: mdl-39159513

ABSTRACT

A new tripodal tris(hydroxycoumarin) based Schiff base, HCTN was synthesized and characterized by FT-IR, 1H NMR, 13C NMR and ESI-HRMS. The probe, HCTN exhibits cyan emission in DMSO/HEPES buffer (9:1, v/v) which selectively detects Cu2+ ion via turn-off fluorescence. The quenching of the fluorescence was due to the binding of the probe, HCTN towards paramagnetic Cu2+ ion resulting in chelation enhanced quenching effect (CHEQ). From the spectroscopic results, the limit of detection of Cu2+ ion was obtained as very low as 0.40 × 10-9 M. The complexation of the metal ion, Cu2+ towards the probe HCTN was confirmed by the ESI-HRMS and Job's plot analysis which supports 1:1 binding stochiometric ratio. In order to validate the affinity of Cu2+ ion towards histidine, the HCTN+Cu2+ system was utilized for the detection of histidine via turn-on mode by the metal displacement approach. The detection limit of His was found to be 7.31 × 10-10 M. In addition to the above, the probe was utilized for various detection applications such as paper strips, cotton swabs, logic gates and thin film applications. The probe, HCTN extends its application to the confocal bioimaging to sense the Cu2+ and Histidine intracellularly.

2.
Article in English | MEDLINE | ID: mdl-39298291

ABSTRACT

SiOx electrodes are promising for high-energy-density lithium-ion batteries (LIBs) due to their ability to mitigate volume expansion-induced degradation. Here, we investigate the surface dynamics of SiOx thin-film electrodes cycled in different carbonate-based electrolytes using a combination of ex situ X-ray photoelectron spectroscopy (XPS) and operando synchrotron X-ray reflectivity analyses. The thin-film geometry allows us to probe the depth-dependent chemical composition and electron density from surface to current collector through the solid electrolyte interphase (SEI), the active material, and the thickness evolution during cycling. Results reveal that SiOx lithiation initiates below 0.4 V vs Li+/Li and indicate a close relationship between SEI formation and SiOx electrode lithiation, likely due to the high resistivity of SiOx. We find similar chemical compositions for the SEI in FEC-containing and FEC-free electrolytes but observe a reduced thickness in the former case. In both cases, the SEI thickness decreases during delithiation due to the removal or dissolution of some carbonate species. These findings give insights into the (de)lithiation of SiOx, in particular, during the formation stage, and the effect of the presence of FEC in the electrolyte on the evolution of the SEI during cycling.

3.
Heliyon ; 10(18): e37776, 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-39315225

ABSTRACT

We present the successful development of a 1089.4 nm Q-switched laser employing a neodymium-doped fiber (NDF) as the active fiber and black phosphorus (BP) as the saturable absorber (SA). The BP SA was fabricated by inserting BP compound into a polyvinyl alcohol (PVA) host polymer, exhibiting a saturable absorption of 2.8 %. Integrated into an NDFL ring cavity, the SA modified the cavity loss, enabling the production of Q-switched pulses. With an increase in the 808 nm pumping power from 108.6 to 155.9 mW, the laser output pulse duration decreased from 3.74 to 3.54 µs, while the repetition rate improved from 40.6 to 51.0 kHz. The laser demonstrated a stable pulse train output, with a fundamental frequency signal to background noise ratio of 45.78 dB. The highest pulse energy of 1.3 nJ was recorded at 155.9 mW pump power. To the best of our knowledge, this represents the first utilization of BP as a SA or Q-switcher within an NDFL cavity.

4.
Article in English | MEDLINE | ID: mdl-39305270

ABSTRACT

Slurry spin coating is an effective approach for the fabrication of protonic ceramic electrolyte thin films. However, weak adhesion between the electrode and spin-coated electrolyte layers in electrochemical cells due to the low sinterability of the proton-conducting perovskite materials usually lead to a high interfacial resistance and thus a low performance. Herein, we report a method to improve the interfacial connection and boost the performance of protonic ceramic cells based on a BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte. Ni-BZCY anode functional layer, BZCY electrolyte layer and La0.6Sr0.4Co0.2Fe0.8O3-δ-BZCY cathode functional layer are all fabricated by slurry spin coating. The electrode functional layers and the components of the electrolyte slurry influence the microstructure of the single cell and the kinetics of the electrochemical processes significantly. A peak power density of 2345 mW cm-2 is achieved at 700 °C in the fuel cell mode, and a current density of -3.0 A cm-2 is obtained at an applied voltage of 1.3 V in the electrolysis mode.

5.
ACS Biomater Sci Eng ; 2024 Sep 23.
Article in English | MEDLINE | ID: mdl-39312410

ABSTRACT

3D printing of microneedles (µNDs) for transdermal therapy has the potential to enable patient personalization based on the target disease, site of application, and dosage requirements. To convert this concept to reality, it is necessary that the 3D printing technology can deliver high resolution, an affordable cost, and large print volumes. With the introduction of benchtop 4K and 8K 3D printers, it is now possible to manufacture medical devices like µNDs at sufficient resolution and low cost. In this research, we systematically optimized the 3D printing design parameters such as resin viscosity, print angle, layer height, and curing time to generate customizable µNDs. We have also developed an innovative 3D coating microtank device to optimize the coating method. We have applied this to the development of novel µNDs to deliver an established NAD+ precursor molecule, nicotinamide mononucleotide (NMN). A methacrylate-based polymer photoresin (eSun resin) was diluted with methanol to adjust the resin viscosity. The 3D print layer height of 25 µm yielded a smooth surface, thus reducing edge-ridge mismatches. Printing µNDs at 90° to the print platform yielded 84.28 ± 2.158% (n = 5) of the input height thus increasing the tip sharpness (48.52 ± 10.43 µm, n = 5). The formulation containing fluorescein (model molecule), sucrose (viscosity modifier), and Tween-20 (surface tension modifier) was coated on the µNDs using the custom designed microtank setup, and the amount deposited was determined fluorescently. The dye-coated µND arrays inserted into human skin (in vitro) showed a fluorescence signal at a depth of 150 µm (n = 3) into the skin. After optimization of the 3D printing parameters and coating protocol using fluorescein, NMN was coated onto the µNDs, and its diffusion was assessed in full-thickness human skin in vitro using a Franz diffusion setup. Approximately 189 ± 34.5 µg (5× dipped coated µNDs) of NMN permeated through the skin and 41.2 ± 7.53 µg was left in the skin after 24 h. Multiphoton microscopy imaging of NMN-coated µND treated mouse ear skin ex vivo demonstrated significantly (p < 0.05) increased free-unbound NADPH and reduced fluorescence lifetime of NADPH, both of which are indicative of cellular metabolic rates. Our study demonstrates that low-cost benchtop 3D printers can be used to print high-fidelity µNDs with the ability to rapidly coat and release NMN which consequently caused changes in intracellular NAD+ levels.

6.
Adv Mater ; : e2412379, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39252633

ABSTRACT

Organic thin film transistors (OTFTs) enable rapid and label-free high-sensitivity detection of target analytes due to their low cost, large-area processing, biocompatibility, and inherent signal amplification. At the same time, the freedom of synthesis, tailorability, and functionalization of organic semiconductor materials and their ability to be combined with flexible substrates make them one of the ideal platforms for biosensing. However, OTFTs-based biosensors still face significant challenges, such as unexpected surface adsorption, disordered conformation, inhomogeneous graft density, and flexibility of probe molecules that biological sensing probes would face during immobilization. In this review, efficient immobilization strategies based on OTFTs biological sensing probes developed in the last 5 years are highlighted. First, the biosensors are classified according to their sensing interface. Second, a comprehensive discussion of the types of biological sensing probes is presented. Third, three commonly used methods for immobilizing biological sensing probes and their challenges are briefly described. Finally, the applications of OTFTs-based biosensors for liquid phase detection are summarized. This review provides a comprehensive and timely review of optimization in sensing interface engineering so that efficient immobilization of biological sensing probes with sensing interfaces will contribute to the development of high-performance OTFTs-based biosensors.

7.
ACS Appl Mater Interfaces ; 16(36): 47820-47831, 2024 Sep 11.
Article in English | MEDLINE | ID: mdl-39219100

ABSTRACT

The exploration of synaptic plasticity in metal-oxide-based ferroelectric thin-film transistors has been limited. As a perovskite ferroelectric material, LiNbO3 is widely studied; but its potential use as a neuromorphic device, like synaptic transistors, has not been realized. In this study, a solution-processed ferroelectric thin-film transistor (FeTFT) with an alternating layer of LiNbO3 and Li5AlO4 as a gate dielectric has been fabricated. This configuration reduces the depolarization field by leveraging the large ionic polarization of Li+ ions in the Li5AlO4 layer, while the wide bandgap helps mitigate the leakage current. FeTFT exhibits impressive transistor performance, including a saturation mobility of 0.478 cm2V-1 s-1, an on/off ratio of 3.08 × 103, and a low trap-state density of 1.3 × 1013 cm-2. Moreover, the device demonstrates good memory retention, retaining information for nearly 1 day. It successfully emulates synaptic plasticity, specifically short-term plasticity and long-term plasticity. Besides, a 94% training accuracy has been achieved through artificial neural network simulation. Notably, the FeTFT consumes minimal power, with energy consumption of approximately 3.09 nJ per synaptic event, which is remarkably low compared to other reported solution-processed FeTFT devices.

8.
ACS Appl Mater Interfaces ; 16(36): 48293-48306, 2024 Sep 11.
Article in English | MEDLINE | ID: mdl-39222057

ABSTRACT

The miniaturization and widespread deployment of electronic devices across diverse environments have heightened their vulnerability to corrosion, particularly affecting copper traces within printed circuit boards (PCBs). Conventional protective methods, such as conformal coatings, face challenges including the necessity for a critical thickness to ensure effective barrier properties and the requirement for multiple steps of drying and curing to eliminate solvent entrapment within polymer coatings. This study investigates cold atmospheric plasma (CAP) as an innovative technique for directly depositing ultrathin silicon oxide (SiOx) coatings onto copper surfaces to enhance corrosion protection in PCBs. A systematic investigation was undertaken to examine how the scanning speed of the CAP deposition head impacts the film quality and corrosion resistance. The research aims to determine the optimal scanning speed of the CAP deposition head that achieves complete surface coverage while promoting effective cross-linking and minimizing unreacted precursor entrapment, resulting in superior electrical barrier and mechanical properties. The CAP coating process demonstrated the capability of depositing SiOx onto copper surfaces at various thicknesses ranging from 70 to 1110 nm through a single deposition process by simply adjusting the scanning speed of the plasma head (5-75 mm/s). Evaluation of material corrosion barrier characteristics revealed that scanning speeds of 45 mm/s of the plasma deposition head provided an effective coating thickness of 140 nm, exhibiting superior corrosion resistance (30-fold) compared to that of uncoated copper. As a proof of concept, the efficacy of CAP-deposited SiOx coatings was demonstrated by protecting an LED circuit in saltwater and by coating printed circuits for potential agricultural sensor applications. These CAP-deposited coatings offer performance comparable to or superior to traditional conformal polymeric coatings. This research presents CAP-deposited SiOx coatings as a promising approach for effective and scalable corrosion protection in miniaturized electronics.

9.
ACS Appl Mater Interfaces ; 16(36): 47854-47865, 2024 Sep 11.
Article in English | MEDLINE | ID: mdl-39223079

ABSTRACT

Correlated transparent conducting oxides (TCOs) have gained great attention, because of their unique combination of transparency and metallic character. SrVO3 (SVO) was identified as a high-performance TCO in the visible range. Few studies have investigated band structure engineering through chemical doping to enhance the optical properties of SVO. Here, we use two different strategies by exploiting the band-filling and width of the bands derived from Vanadium to tune the screened plasma frequency ωp* and the interband transition Ep-d energy, corresponding to the optical transparency window edges. For control of the band-filling strategy, it is found that Titanium doped SVO has a wide transparency window, but such a composition does not maintain the high electrical conductivity required for TCO applications. Concerning the bandwidth strategy, the doping of SrVO3 by Calcium shows that ωp* remains located in the IR range (1.12 eV), while Ep-d is blue-shifted into the UV region (3.43 eV) due to reinforced electronic correlations. By an appropriate choice of dopant, we successfully increased the size of the transparency window by around 11% from 1.94 eV (SVO) to 2.30 eV (Calcium-doped SVO), while retaining high conductivity of around 2.30 × 104 (S·cm-1) and high charge carrier density of 2.93 × 1022 cm-3.

10.
MethodsX ; 13: 102914, 2024 Dec.
Article in English | MEDLINE | ID: mdl-39253006

ABSTRACT

This review critically assesses the determination of low molecular weight volatiles by different methods, providing context for the development of suitable techniques to determine volatile content in plant tissue and soil samples as well as the associated analytical challenges. Although sensitive analytical methods have been reported in recent decades, studies on their application in modern investigative techniques are lacking. Herein, the latest sampling methods in volatile biochemistry, current advancements in the understanding of these analytes, and the significance of these findings for other types of volatiles are summarized. Gas chromatography, high-performance liquid chromatography, ion chromatography, thin-film microextraction, and real-time monitoring techniques are discussed and critically determined. This review concerns the methods most suitable for future research in this area.

11.
Heliyon ; 10(17): e36965, 2024 Sep 15.
Article in English | MEDLINE | ID: mdl-39281428

ABSTRACT

Wide-gap Cu(In,Ga)Se2 (CIGS) solar cells exhibit a superior match to the solar spectrum, resulting in a higher ideal efficiency (E ff). However, in reality, their device E ff is lower than that of narrow-gap CIGS solar cells. This study aims to identify the factors that limit the performance enhancement of wide-gap CIGS solar cells, focusing on the characteristics of the buffer layer. The influence of the thickness and doping concentration of the CdS layer on the built-in electric field and interfacial recombination of the heterojunction has been investigated through simulation. The simulation results indicate that when the doping concentration of the CdS layer is lower than or similar to that of the CGS layer, decreasing the thickness of the CdS layer (e.g., 10 nm) is beneficial for improving device performance. However, if it is higher than that of the CGS layer, increasing the thickness of the CdS layer (e.g., 50 nm) is conducive to improving device performance. The thickness of the CdS layer that maximizes the E ff of the wide-gap CGS device should be approximately 50 nm, and its doping concentration should be higher than that of the CGS layer. This optimization can simultaneously enhance the built-in electric field of the heterojunction and minimize its interfacial recombination, thereby improving the open-circuit voltage and E ff of wide-gap CGS devices.

12.
Adv Mater ; : e2410383, 2024 Sep 17.
Article in English | MEDLINE | ID: mdl-39286858

ABSTRACT

Renal sympathetic nerves play a crucial role in the pathogenesis of hypertension, and renal denervation (RDN) is a new solution for patients with refractory hypertension. However, current RDN techniques show inconsistent results in clinical application probably owing to incomplete endovascular ablation of the sympathetic nerves and a lack of measures to localize and assess efficacy. In this study, a closed-loop RDN system consisting of a sensing unit with a piezoelectric thin-film sensor (PTFS) and a treatment unit with a hollow Pd nanoparticle shell (PdNPS) with a diameter of 202.0 nm for photothermal neural ablation is constructed. The PTFS can monitor and collect arterial pulsation and blood pressure (BP) and direct PdNPS to maximize RDN. PdNPS maintains a local temperature of 58-62 °C under near-infrared-II irradiation (1,064 nm) to achieve effective RDN within a range of 90-120 s treatment window. Photothermal ablation significantly inhibits the activities of renal sympathetic nerves post-procedure and after one month and reduces the elevation of BP by > 50%. The novel closed-loop system enables safe and efficient targeting, dynamic monitoring, and ablation of the renal sympathetic nerves. This closed-loop system provides a new strategy for RDN technology and even for treating sympathetic nerve-related chronic diseases.

13.
Nano Lett ; 24(37): 11676-11682, 2024 Sep 18.
Article in English | MEDLINE | ID: mdl-39225551

ABSTRACT

Second-order nonlinearity gives rise to many distinctive physical phenomena, e.g., second-harmonic generation, which play an important role in fundamental science and various applications. Lithium niobate, one of the most widely used nonlinear crystals, exhibits strong second-order nonlinear effects and electro-optic properties. However, its moderate refractive index and etching sidewall angle limit its capability in confining light into nanoscales, thereby restricting its application in nanophotonics. Here, we exploit nanocavities formed by second-order circular Bragg gratings, which support resonant anapole modes, to achieve a 42 000-fold enhanced second-harmonic generation in thin-film lithium niobate. The nanocavity exhibits a record-high normalized conversion efficiency of 1.21 × 10-2 cm2/GW under the pump intensity of 1.9 MW/cm2. Besides, we also show s- and p-polarization-independent second-harmonic generation in elliptical Bragg nanocavities. This work could inspire the study of nonlinear optics at the nanoscale on thin-film lithium niobate, as well as other novel photonic platforms.

14.
Sensors (Basel) ; 24(17)2024 Sep 01.
Article in English | MEDLINE | ID: mdl-39275602

ABSTRACT

ZnO film ultrasonic transducers for temperature and stress measurements with dual-mode wave excitation (longitudinal and shear) were deposited using the reactive RF magnetron sputtering technique on Si and stainless steel substrates and construction steel bolts. It was found that the position in the substrate plane had a significant effect on the structure and ultrasonic performance of the transducers. The transducers deposited at the center of the deposition zone demonstrated a straight columnar structure with a c-axis parallel to the substrate normal and the generation of longitudinal waves. The transducers deposited at the edge of the deposition zone demonstrated inclined columnar structures and the generation of dominant shear or longitudinal shear waves. Transducers deposited on the bolts with dual-wave excitation were used to study the effects of high temperatures in the range from 25 to 525 °C and tensile stress in the range from 0 to 268 MPa on ultrasonic response. Dependencies between changes in the relative time of flight and temperature or axial stress were obtained. The dependencies can be described by second-order functions of temperature and stress. An analysis of the contributions of thermal expansion, strain, and the speed of sound to changes in the time of flight was performed. At high temperatures, a decrease in the signal amplitude was observed due to the decreasing resistivity of the transducer. The ZnO ultrasonic transducers can be used up to temperatures of ~500 °C.

15.
Sensors (Basel) ; 24(17)2024 Sep 07.
Article in English | MEDLINE | ID: mdl-39275731

ABSTRACT

Accurate measurement of the pretightening stress for bolts has great significance for improving the assembly quality and safety, especially in severe environments. In this study, AlN thin film transducers were deposited on GH4169 nickel base alloy bolts using the RF magnetron sputtering, enabling a systematic investigation into the correlation between structures and the intensity of ultrasonic echo signals. Employing the finite element method resulted in consistency with the experimental data, enabling further exploration of the enhancement mechanism. With the increasing thickness of both the piezoelectric layer and the electrode layer, the intensity of the ultrasonic echo signals saw a great enhancement. The maximum-intensity observed increase is 14.7 times greater than that of the thinnest layers. Specifically, the thicker piezoelectric layer improves its mechanical displacement, while the increased thickness of the electrode layer contributes to better densification. An electrode diameter of nearly 4 mm is optimal for an AlN thin film transducer of M8 bolts. For pretightening the stress measurement, the sample with a strong and stable echo signal shows a low measurement error of pretightening below ±2.50%.

16.
J Colloid Interface Sci ; 678(Pt B): 1049-1060, 2024 Sep 13.
Article in English | MEDLINE | ID: mdl-39276514

ABSTRACT

HYPOTHESIS: The structural details of foams made with pea albumins are affected by the pH of the initial solution and followed heat treatment. EXPERIMENTS: An in situ, time-resolved investigation of foams prepared with pea albumins was conducted using small-angle neutron scattering (SANS) in combination with imaging and conductance measurements. Solutions were tested at pH three pH values (3, 4.5, and 8) before and after heating (90 °C for 1 and 5 min). FINDINGS: The characteristic structures present in the foam from the nano to the meso-scale differed during drainage depending on solution pH. Foams obtained at pH 3, had the largest bubble radius and thinnest plateau border, as well as the highest extent of liquid drainage. At pH 4.5, close to the isoelectric point of the proteins, foams displayed similar bubbles' behavior to those at pH 8, but with the largest film thickness. In this case, the proteins were extensively aggregated. Heating of the solutions prior to foaming did not significantly affect the foam aging regardless of pH. The quantification of specific surface areas and film thickness over time without sample disruption shows to be a powerful approach to designing foam structures.

17.
Small Methods ; : e2401339, 2024 Sep 16.
Article in English | MEDLINE | ID: mdl-39279567

ABSTRACT

Vapor-deposited inverted perovskite solar cells utilizing self-assembled monolayer (SAM) as hole transport material have gained significant attention for their high efficiencies and compatibility with silicon/perovskite monolithic tandem devices. However, as a small molecule, the SAM layer suffers low thermal tolerance in comparison with other metal oxide or polymers, rendering poor efficiency in solar device with high-temperature (> 160 °C) fabricating procedures. In this study, a dual modification approach involving AlOx and F-doped phenyltrimethylammonium bromide (F-PTABr) layers is introduced to enhance the buried interface. The AlOx dielectric layer improves the interface contact and prevents the upward diffusion of SAM molecules during the vapor-solid reaction at 170 °C, while the F-PTABr layer regulates crystal growth and reduces the interfacial defects. As a result, the AlOx/F-PTABr-treated perovskite film exhibits a homogeneous, pinhole-free morphology with improved crystal quality compared to the control films. This leads to a champion power conversion efficiency of 21.53% for the inverted perovskite solar cells. Moreover, the encapsulated devices maintained 90% of the initial efficiency after 600 h of ageing at 85 °C in air, demonstrating promising potential for silicon/perovskite tandem application.

18.
Adv Colloid Interface Sci ; 333: 103298, 2024 Sep 04.
Article in English | MEDLINE | ID: mdl-39243484

ABSTRACT

This review paper focuses on group IVB transition metal nitrides (TMNs) such as titanium nitride (TiN), zirconium nitride (ZrN), and hafnium nitride (HfN) and as alternative plasmonic materials to noble metals like gold and silver. It delves into the fabrication methods of these TMNs, particularly emphasizing thin film fabrication techniques like magnetron sputtering and atomic layer deposition, as well as nanostructure fabrication processes applied to these thin films. Overcoming the current fabrication and application-related challenges requires a deep understanding of the material properties, deposition techniques, and application requirements. Here, we discuss the impact of fabrication parameters on the properties of resulting films, highlighting the importance of aligning fabrication methods with practical application requirements for optimal performance. Additionally, we summarize and tabulate the most recent plasmonic applications of these TMNs in fields like biosensing, photovoltaic energy, and photocatalysis, contributing significantly to the current literature by consolidating knowledge on TMNs.

19.
Mikrochim Acta ; 191(10): 581, 2024 09 07.
Article in English | MEDLINE | ID: mdl-39243346

ABSTRACT

To meet the needs of developing efficient extractive materials alongside the evolution of miniaturized sorbent-based sample preparation techniques, a mesoporous structure of g-C3N4 doped with sulfur as a heteroatom was achieved utilizing a bubble template approach while avoiding the severe conditions of other methods. In an effort to increase the number of adsorption sites, the resultant exfoliated structure was then modified with thymol-coumarin NADES as a natural sorbent modifier, followed by introduction into a nylon 6 polymer via an electrospinning process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis validated S-doped g-C3N4 and composite production. The prepared electrospun fiber nanocomposite, entailing satisfactory processability, was then successfully utilized as a sorbent in on-chip thin film micro-solid-phase extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from saliva samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Utilizing a chip device, a thin film µ-SPE coupled with LC-MS/MS analysis yielded promising outcomes with reduced sample solution and organic solvents while extending lifetime of a thin film sorbent. The DES-modified S-doped g-C3N4 amount in electrospun was optimized, along with adsorption and desorption variables. Under optimal conditions, selected NSAIDs were found to have a linear range of 0.05-100.0 ng mL-1 with an R2 ≥ 0.997. The detection limits were ranged between 0.02 and 0.2 ng mL-1. The intra-day and inter-day precisions obtained were less than 6.0%. Relative recoveries were between 93.3 and 111.4%.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal , Deep Eutectic Solvents , Graphite , Limit of Detection , Nanofibers , Saliva , Tandem Mass Spectrometry , Saliva/chemistry , Tandem Mass Spectrometry/methods , Graphite/chemistry , Nanofibers/chemistry , Humans , Adsorption , Anti-Inflammatory Agents, Non-Steroidal/analysis , Porosity , Deep Eutectic Solvents/chemistry , Chromatography, Liquid/methods , Nitrogen Compounds/chemistry , Solid Phase Microextraction/methods , Solid Phase Extraction/methods
20.
Philos Trans A Math Phys Eng Sci ; 382(2281): 20230322, 2024 Oct 23.
Article in English | MEDLINE | ID: mdl-39246080

ABSTRACT

Polymers have distinctive optical properties and facile fabrication methods that have been well-established. Therefore, they have immense potential for nanophotonic devices. Here, we demonstrate the temperature-sensing potential of SU8-meta-phenylenediamine (SU8-mPD), produced by epoxy amination of the SU-8 polymer. Its properties were examined through a series of molecular structural techniques and optical methods. Thin layers have demonstrated optical emission and absorption in the visible range around 420 and 520 nm, respectively, alongside a strong thermal responsivity, characterized by the 18 ppm °C-1 expansion coefficient. A photonic chip, comprising a thin 5-10 µm SU8-mPD layer, encased between parallel silver and/or gold thin film mirrors, has been fabricated. When pumped by an external light source, this assembly generates a pronounced fluorescent signal that is superimposed with the Fabry-Pérot (FP) resonant response. The chip undergoes mechanical deformation in response to temperature changes, thereby shifting the FP resonance and encoding temperature information into the fluorescence output spectrum. The time response of the device was estimated to be below 1 s for heating and a few seconds for cooling, opening a new avenue for optical sensing using SU8-based polymers. Thermoresponsive resonant structures, encompassing strong tunable fluorescent properties, can further enrich the functionalities of nanophotonic polymer-based platforms. This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'.

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