Absorption Intensity Research Articles

Alternating Donor‐Acceptor Ladder‐Type Heteroarene for Efficient Photothermal Conversion via Boosting Non‐Radiative Decay

The development of novel ladder‐type conjugated molecules is crucial for advancing supramolecular chemistry and material science. In this study, we report a straightforward synthesis of new alternating donor‐acceptor (D‐A) ladder‐type heteroarene, FCDTDPP, and demonstrate its application as photothermal agent for imaging and cancer therapy. FCDTDPP is constructed by vinylene bridge between cyclopentadithiophene (D) and diketopyrrolopyrrole (A) through intramolecular Friedel‐Crafts type reaction. FCDTDPP exhibits unique combination of good molecular planarity, efficient intra/inter‐molecular mixed D‐A interactions, and local aromaticity. These features collectively contribute to its broad and intense absorptions with narrow bandgap in red band of the spectra, coupled with multiple vibrational absorption feature, thereby enhancing non‐radiative decay process and resulting in efficient photothermal conversion property. FCDTDPP and its nanoparticles (NPs) exhibit superior photothermal conversion performance and stability under 660 nm laser irradiation. Moreover, in vitro studies reveal that FCDTDPP NPs possess excellent biocompatibility, low cytotoxicity, and robust photothermal therapeutic efficacy, a finding further corroborated by preliminary in vivo experiments in tumor‐bearing mice. This work charts a novel course for the molecular engineering of organic photothermal conversion systems, propelling relevant research forward.

Alternating Donor‐Acceptor Ladder‐Type Heteroarene for Efficient Photothermal Conversion via Boosting Non‐Radiative Decay

The development of novel ladder‐type conjugated molecules is crucial for advancing supramolecular chemistry and material science. In this study, we report a straightforward synthesis of new alternating donor‐acceptor (D‐A) ladder‐type heteroarene, FCDTDPP, and demonstrate its application as photothermal agent for imaging and cancer therapy. FCDTDPP is constructed by vinylene bridge between cyclopentadithiophene (D) and diketopyrrolopyrrole (A) through intramolecular Friedel‐Crafts type reaction. FCDTDPP exhibits unique combination of good molecular planarity, efficient intra/inter‐molecular mixed D‐A interactions, and local aromaticity. These features collectively contribute to its broad and intense absorptions with narrow bandgap in red band of the spectra, coupled with multiple vibrational absorption feature, thereby enhancing non‐radiative decay process and resulting in efficient photothermal conversion property. FCDTDPP and its nanoparticles (NPs) exhibit superior photothermal conversion performance and stability under 660 nm laser irradiation. Moreover, in vitro studies reveal that FCDTDPP NPs possess excellent biocompatibility, low cytotoxicity, and robust photothermal therapeutic efficacy, a finding further corroborated by preliminary in vivo experiments in tumor‐bearing mice. This work charts a novel course for the molecular engineering of organic photothermal conversion systems, propelling relevant research forward.

Plasmon-enhanced NIR-II photoluminescence of rare-earth oxide nanoprobes for high-sensitivity optical temperature sensing

With ongoing advancements in photothermal therapy, achieving efficient tumor cell eradication while minimizing damage to healthy tissues necessitates a highly effective and non-invasive real-time temperature monitoring technique for human tissues. Herein, we report a near-infrared (NIR)-II optical temperature sensing nanoprobe featuring rare-earth-doped gadolinium oxide nanocrystals (RENCs) attached to the dumbbell mesoporous silica-coated gold nanorods (AuNRs). The composite nanoprobe presents an intense absorption in the NIR region, and NIR-II photoluminescence (PL) increases by 97.2 to 102-fold compared to pure RENCs upon 980 nm irradiation. The localized electric field generated through surface plasmon resonance effects of AuNRs demonstrated a dumbbell-shaped distribution that aligns with the structure of nanoprobes, maximizing the PL enhancement of RENCs. Moreover, the NIR-II emissions are changed with the rising temperature, with an exceptional relative sensitivity of 7.25% K−1 at 338 K based on PL lifetime, indicating the nanoprobe is highly potential for optical temperature sensing.

Carbon dots nanoparticles derived from showy Asian grapes (Medinilla speciosa) for free radical scavenger

Carbon dot nanoparticles (CNPs) were synthesized from the peels of showy Asian grapes (Medinilla speciosa) using microwave irradiation for free radical scavenging. The optimal emission and absorption intensities were achieved with a 50-min irradiation duration, at wavelengths of 430 nm and 267 nm, respectively. XRD analysis revealed characteristic peaks at angles of 26.37° and 29.63°. FTIR analysis indicated that antioxidant potential is attributed to hydroxyl and carboxyl groups on the CNPs’ surface. TEM images showed diameters ranging from 2 nm to 8 nm. The CNPs exhibited 73.82% antioxidant activity at 5 mg/mL, with an IC50 value of 6.89 ppm, indicating strong antioxidant activity. Additionally, the CNPs demonstrated good storage stability, suggesting potential applications in food supplements and biomedical materials.

A Comprehensive Quality Evaluation for Gentiana Rigescens Franch. by Fingerprinting Combined with Chemometrics and Network Pharmacology.

Gentiana rigescens Franch. (G. rigescens) is a unique traditional medicinal herb from southwestern China, and its clinical mechanism for the treatment of hepatitis and the quality differences between different origins are not clear. The research aims to analyze the mechanisms for the treatment of hepatitis and differences in inter-origin differences using analytical techniques, chemometrics, and network pharmacology. Through infrared spectroscopy, spectral images, and high-performance liquid chromatography (HPLC) analysis, it was found that there were differences in absorbance intensity and significant differences in compound content among the samples' origin. G. rigescens iridoids and flavonoids exert therapeutic effects on hepatitis through multiple targets (GAPDH, EGFR, and MMP9, etc.) and multiple pathways (non-small cell lung cancer, hepatitis C, etc.). The above HPLC, chemometrics, and network pharmacology results revealed that gentiopicroside, and swertiamarine was the best quality marker among origins. The accuracy of the ResNet model train, test, and external validation sets for synchronous spectral images were 100 %, which could be utilized as an effective tool for tracing G. rigescens's origins. The R2 of the calibration and validation sets of the PLSR model was higher than 0.70. This model had excellent predictive performance in determining the content of gentiopicroside and swertiamarine, and could quickly, accurately, and effectively predict these two compounds. The research investigates the differences in G. rigescens origins from multiple perspectives, establishes image recognition models and prediction models, and provides new methods and theoretical basis for quality control of G. rigescens.

Solid-state solvatochromism of oxazolidine in multi-functionalized copolymer nanoparticles: Development of advanced materials with multi-color fluorescence

Investigating the solvatochromism of stimuli-chromic compounds such as oxazolidine in polymer matrices with various polarities or functionalities is a unique approach to developing advanced materials for anticounterfeiting, sensor, optoelectronic, and displayers. In a novel strategy, multi-functionalized copolymer nanoparticles were synthesized by copolymerization of methyl methacrylate (MMA) with various functional comonomers in emulsion media for post-polymerization modification with oxazolidine and investigation of its solvatochromism in both colloidal solution and solid phase. The particle size and morphology of nanoparticles were influenced significantly by the polarity of functional groups, and the morphology evolution from sphere to anisotropic shapes was observed by increasing the polarity of functional groups. Investigation of oxazolidine solvatochromism in colloidal solution and solid polymer powders indicated different mechanisms for solvatochromism, in which the polarity of media is the main effective parameter in colloidal solution and the polarity of functional groups in the polymer structure is the main effective parameter in solid polymer phase. The solvatochromism of oxazolidine was confirmed by observed red shift and blue shift in UV–Vis and fluorescence spectra, in which the intensity of absorbance and emission peaks was changed as a function of the polarity of functional groups. Solvatochromic photoluminescent polymer nanoparticles were used for several advanced applications such as solid anticounterfeiting inks to information encryption, dual-mode visualization of latent fingerprints, and also development of organic light-emitting diodes (OLEDs). For the first time, the results indicate a significant effect of polymer chain local polarity induced by functional groups on the tuning of optical properties of the oxazolidine by the solid-state solvatochromic phenomenon. Solvatochromism of oxazolidine in functionalized polymer nanoparticles is an interesting approach to developing novel intelligent materials that have advanced applications in different fields such as anticounterfeiting and information encryption, optoelectronic, polarity sensor, and visualization of latent fingerprints.

Investigation of the Effects of Different Phases of TiO2 Nanoparticles on PVA Membranes

Introduction: PVA/TiO2 nanocomposite membranes are prepared by solution casting technique where different phases of TiO2 nanoparticles like brookite, brookiterutile and rutile are dispersed in PVA matrix. Sol-gel method was employed to prepare TiO2 nanoparticles, while different phases of TiO2 have been obtained by controlling the calcination temperature. Methods: PVA/TiO2 nanocomposite membranes were characterized by XRD, FTIR, AFM, TEM, UV-visible and PL techniques. XRD results confirmed the presence of different phases of TiO2, exhibiting 3.3 nm, 8.4 nm, and 35.7 nm mean crystalline size. The XRD studies also confirmed that TiO2 nanoparticles became properly dispersed to the PVA matrix, leading to increased PVA crystallinity after doping of different phases of TiO2 nanoparticles. UV-visible analysis revealed an increase in absorption intensity and peak position shifts slightly towards longer wavelengths, which indicates that nanofillers tuned the band gap of PVA. The doping of the TiO2 (brookite) phase in the PVA matrix results in a decreased in PL intensity. Results: This suggests that the PVA/TiO2 (brookite) membrane exhibits a greater degree of photocatalytic activity in comparison to the other two composites. According to the FTIR investigation, the hydroxyl (OH) groups present in PVA interact with the dopants Ti+ ions via intra- and intermolecular hydrogen bonds to produce charge transfer complexes (CTC). The AFM study shows surface roughness details for PVA and PVA/TiO2 composite membranes. The average grain size of TiO2 nanoparticles calculated from TEM images is in good agreement with the grain size calculated by XRD. Conclusion: By adjusting the phase of TiO2 nanoparticles into PVA matrix, composites can be developed that are optimized for a variety of applications such as water purification, UV protection, self-cleaning surfaces, lithium-ion batteries, and optoelectronic devices.

Synthesis of heavy-atom-free thienoisoindigo dye as near-infrared photosensitizer for type I photodynamic therapy and photoacoustic imaging

Thienoisoindigo (TIIG) has been extensively employed as promising building block of near-infrared (NIR) dyes and organic semiconductor materials. Herein, heavy-atom-free TIIG-based NIR dye TIIGTPA is reported as photosensitizer for combinational photodynamic and photothermal therapy and photoacoustic imaging (PAI). By introducing two methoxy-substituted triphenylamines as the rotors and electron donors at the periphery sites of the electron-deficient TIIG core, dye TIIGTPA featuring Donor-Acceptor-Donor (D-AD) structure is constructed with intensive NIR absorption. Through co-assembly with amphipathic F-127, water-soluble TIIGTPA NPs were prepared with good superoxide anion radical (O2-•) production and high photothermal conversion efficiency (PCE) of 59.0 % under 730 nm photoirradiation. Additionally, the excellent photothermal effect enabled a superior photoacoustic response for tumor blood vessel visualization through PAI. All results indicated the favorable potential of TIIGTPA NPs for PAI-mediated combinational phototherapy.

Glycation modification of protein hydrolysate from channel catfish (Ictalurus Punetaus) viscera to mitigate undesirable flavor: Unraveling structure and flavor characteristics

To investigate the impacts of glycation modification on the structure and flavor of fish viscera-derived protein hydrolysates, channel catfish viscera was utilized and hydrolyzed by Flavourzyme, followed by glycation with glucosamine, xylose, ribose and glucose, respectively. The structural characteristics, taste and odor of glycated products were evaluated. The results revealed that glycation led to an increase in peptides (<1 kDa) and a decrease in peptide fraction (>5 kDa). UV and fluorescence spectra indicated a gradual rise in absorbance and fluorescence intensity. Glucosamine-induced glycation significantly mitigated bitterness, while enhancing saltiness and umami. GC–MS/MS analysis revealed that glycation led to reduced undesirable odor, and formation of aromatic compounds. LC-MS/MS identified Arg and Lys as the main modification sites. Interestingly, aldehydes were found to modify peptides via carbonyl-amine reaction, leading to decreased fishy odor. The present study contributes to flavor improvement of fish viscera-derived peptides through glycation and high-value utilization of fish viscera.

Experimental and calculation investigations of the photocatalytic selective and performance for CO2 reduction by cobalt-doped Bi4O5Br2 nanosheets

This study delves into the photocatalytic process of an innovative Co-doped Bi4O5Br2 material synthesized through a straightforward process. Experimental and theoretical findings corroborate that cobalt doping remarkably enhances the CO2 reduction capability of Bi4O5Br2 catalysts under visible light. Findings indicate that Co-doped Bi4O5Br2 exhibits substantial advantages over its pristine counterpart in photocatalytic CO2 reduction. Notably, the catalyst with 4 at.% Co doping demonstrates the highest photocatalytic CO2 reduction efficiency, achieving CO and methane production activities of up to 9.46 and 0.20 μmol/g/h, respectively. Furthermore, the low activation energy for CO2 reduction in Co-doped Bi4O5Br2, as indicated by reaction pathways calculations, facilitates the process. Detailed experimental results reveal that Co incorporation does not alter the surface morphology or the crystalline phase of the photocatalyst. The superior efficiency of Co-doped Bi4O5Br2 is attributed to multiple factors: a narrow band gap, expanded visible light absorption spectrum, greater absorption intensity within the visible range, and enhanced separation efficiency of photogenerated electrons and holes compared to pristine Bi4O5Br2. This highlights the practical application of Co-doped Bi4O5Br2 for enhancing photocatalytic performance, supporting future advancements in solar energy utilization and the creation of high-value chemical products.

Investigating Flavonoids by HPTLC Analysis Using Aluminium Chloride as Derivatization Reagent

This is the first study to report on high performance thin layer chromatography (HPTLC) generated spectrophotometric data to systematically capture flavonoid compounds using optimized derivatization with either AlCl3 or NaNO2-AlCl3-NaOH as visualisation reagents. While the traditional AlCl3 colorimetric method using UV–Vis analysis provides valuable insights into the presence of flavonoids and allows derivation of the total flavonoid content (TFC) of a sample, HPTLC fingerprints obtained after spraying with AlCl3 or NaNO2-AlCl3-NaOH enable the visualization of the various flavonoids present in a sample based on their respective absorption shifts, thus complementing the traditional TFC assay. In this study, 40 different flavonoids representing different classes (flavonols, flavanolols, flavan-3-ol, flavones, flavanones, and isoflavonoids) were analysed. Upon derivatization with AlCl3 most of the investigated flavonoids recorded bathochromic shifts, yielding characteristic λmax values between 370 and 420 nm, while spraying with NaNO2-AlCl3-NaOH triggered hyperchromic shifts, and thus an increase in absorbance intensity in flavonoids with particular substitution patterns. A few non-flavonoid components with structural similarities to flavonoids (e.g., rosmarinic acid, gallic acid, aspirin, salicylic acid) served as the negative control in this study to determine whether the derivatization reagents allowed exclusive detection of flavonoids. The method was then applied to the analysis of flavonoid containing supplements as well as red clover honey to demonstrate the method’s application in the analysis of natural products.

Revealing the effect of hydrothermal processing of legumes on the accumulation of dry matter in aquafaba

Legumes are an affordable source of vegetable protein, fiber, and vitamins, and due to their high nutritional and biological value, they are widely used in the nutrition of various categories of consumers. The main methods of processing legumes include hydromechanical and hydrothermal treatment, which is aimed at achieving culinary readiness of boiled legumes. Studying the parameters of the specified technological process for the accumulation of dry substances in aquafaba could make it possible to influence the composition and properties of this liquid, which would provide opportunities for its use in the food industry. The influence of hydrothermal processing of leguminous grains on the accumulation of dry matter in aquafaba, as well as the kinetics of moisture content of various types of leguminous grains, have been experimentally investigated, which made it possible to determine the rational parameters of hydromechanical and hydrothermal processing of chickpeas, beans, peas, lentils, with the preparation of boiled leguminous grains and aquafaba. It was determined that during hydromechanical processing intensive moisture absorption occurs in the first hours and reaches up to 80 % of the initial mass, after which the intensity of water absorption decreases somewhat. Rational technological parameters of hydrothermal processing of leguminous grains by two methods, basic (cooking at a temperature of 99±1 °С) and under pressure (cooking in a pressure cooker at a temperature of 120±1 °С) were established in the relationship "achieving the readiness of legumes – the content of dry substances in aquafaba". The use of the above-mentioned techniques for hydrothermal processing of leguminous grains make it possible to obtain the content of dry substances in aquafaba in the range of 2.8–4.8 % for cooking by the main technique and 3.9–7.0 % under pressure cooking conditions. To understand the processes regarding the influence of hydrothermal processing of legume grains on the accumulation of dry substances, the Peleg model was used. The experimental data could be used to substantiate parameters for the technological process to produce foods based on legumes

Novel Structures for PV Solar Cells: Fabrication of Cu/Cu2S-MWCNTs 1D-Hybrid Nanocomposite

The production of cost-effective novel materials for PV solar cells with long-term stability, high energy conversion efficiency, enhanced photon absorption, and easy electron transport has stimulated great interest in the research community over the last decades. In the presented work, Cu/Cu2S-MWCNTs nanocomposites were produced and analyzed in the framework of potential applications for PV solar cells. Firstly, the surface of the produced one-dimensional Cu was covered by Cu2S nanoflake. XRD data prove the formation of both Cu and Cu2S structures. The length and diameter of the one-dimensional Cu wire were 5–15 µm and 80–200 nm, respectively. The thickness of the Cu2S nanoflake layer on the surface of the Cu was up to 100 nm. In addition, the Cu/Cu2S system was enriched with MWCNTs. MWCNs with a diameter of 50 nm interact by forming a conductive network around the Cu/Cu2S system and facilitate quick electron transport. Raman spectra also prove good interfacial coupling between the Cu/Cu2S system and MWCNTs, which is crucial for charge separation and electron transfer in PV solar cells. Furthermore, UV studies show that Cu/Cu2S-MWCNTs nanocomposites have a wide absorption band. Thus, MWCNTs, Cu, and Cu2S exhibit an intense absorption spectrum at 260 nm, 590 nm, and 972 nm, respectively. With a broad absorption band spanning the visible–infrared spectrum, the Cu/Cu2S-MWCNTs combination can significantly boost PV solar cells’ power conversion efficiency. Furthermore, UV research demonstrates that the plasmonic character of the material is altered fundamentally when CuS covers the Cu surface. Additionally, MWCN-Cu/Cu2S nanocomposite exhibits hybrid plasmonic phenomena. The bandgap of Cu/Cu2S NWs was found to be approximately 1.3 eV. Regarding electron transfer and electromagnetic radiation absorption, the collective oscillations in plasmonic metal-p-type semiconductor–conductor MWCNT contacts can thus greatly increase energy conversion efficiency. The Cu/Cu2S-MWCNTs nanocomposite is therefore a promising new material for PV solar cell application.

Outstanding performance of Co-doped ZnS nanoparticles used as nanocatalyst for synthetic dye degradation

In this work, fabrication of pure and cobalt (Co) doped zinc sulfide (ZnS) nanoparticles were carried out via facile co-precipitation technique using thioglycolic acid as a surfactant. The synthesized nano powders were employed to characterize using various techniques like X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and UV–Vis spectroscopy, to elucidate the alterations in the structure and morphology of nanomaterials. The XRD analysis revealed wurtzite phase of fabricated nanoparticles. Inclusion of Co dopants failed to modify the lattice structure of host material. Analysis of UV–Vis spectroscopy indicates intensive absorption in the visible region upon doping. FTIR spectroscopy was employed to identify functional groups affiliated with molecular vibrations. The photoactivity and kinetics of photo-products were evaluated by monitoring degradation of methylene blue (MB) by solar irradiation. Photodecomposition of MB was significantly increased when Co doped ZnS was employed relative to pristine ZnS. This novel technique of doped ZnS nanoparticles provide an effectual and sustainable route for treatment of wastewater.

Four ecofriendly spectrophotometric methods for the determination of perindopril through derivatization with sulphophtalein dyes: application to tablet analysis

Nowadays, there is a need to expand the bank of spectrophotometric methods for the determination of perindopril in dosage forms for the purposes of routine pharmaceutical analysis, which would be simple, express, «green» and inexpensive. In the present work, perindopril in tablets was quantified via a direct simple, «green», and non-extracting spectrophotometric approach based on the formation of ion-pair complexes with sulphophtalein dyes. The absorbances of the colored reaction products were registered at 405 nm (bromocresol green, BCG), 397 nm (bromocresol purple, BCP, and bromothymol blue, BTB) and 598 nm (bromophenol blue, BPB). To achieve the highest intensity of absorbance, optimum conditions were established by the screening of many experimental factors such as optimal concentration and volume of dyes, and the time consumed for the reaction. Beer’s law was obeyed in the ranges of 0.44–3.96 µg/mL (BCG), 3.00–7.00 µg/mL (BCP), 4.00–12.00 µg/mL (BTB) and 0.44–3.52 µg/mL (BPB). All four methods were validated in accordance with ICH guidelines, confirming specificity and linearity, accuracy and precision, limits of detection and quantification, robustness. These validated methods provide a reliable and green approach for the quantitative analysis of perindopril in tablets, contributing to safer and more sustainable laboratory practices in pharmaceutical analysis.

Conjugated Diphenylaniline-Azulene Co-Oligomers with Intense Absorption and Emission in the Visible Region

New conjugated 2,6-diphenylaniline-azulene co-oligomers of linear and branched structure were synthesized by the interaction of borylazulenes with diphenylaniline bromides under Suzuki–Miyaura cross-coupling conditions. The obtained diphenylaniline-azulene co-oligomers intensively absorb and emit visible light (410–700 nm region); in particular, they exhibit strong emissions in the green, as well as orange, range, with maxima of 510/590 nm. It is shown that such properties appear as a result of the positive resonance exposure to aniline fragments significantly rearranging the electronic structure of azulene, in particular, the levels and energy gaps of frontal HOMO–LUMO orbitals.

Deep neural network-enabled dual-functional wideband absorbers

The increasing interest in switchable and tunable wideband perfect absorbers for applications such as modulation, energy harvesting, and spectroscopy has significantly driven research efforts. In this study, we present a dual-function terahertz (THz) metamaterial absorber supported by deep neural networks (DNN). This absorber achieves dual-wideband perfect absorption through the use of graphene and vanadium dioxide (VO₂), enabling both switching and tuning functionalities. Simulation results show that, in the insulating phase of VO₂, a high-frequency wideband absorption ranging from 9.31 to 9.77 THz is achieved, with an absorption rate exceeding 90%. In contrast, in the metallic phase of VO₂, a full-band wideband absorption above 90% is observed from 8.44 to 9.75 THz. The corresponding fractional bandwidths are 61.3% and 174.6%, respectively. Additionally, electrical tuning of graphene’s Fermi level from 0.01 to 1 eV enables continuous modulation of absorption intensity between 48 and 100%. The absorber also exhibits polarization insensitivity to TE and TM waves due to its symmetric design and broad incidence angle. This design holds significant potential for various THz applications, including switching, electromagnetic shielding, stealth technology, filtering, and sensing.

Modified perylene diimide for femto molar level detection of glucose: smartphone-assisted colorimetric glucose detection kits.

In this report, a functionalized hydroxyphenyl benzothiazole (HBT) derivative has been synthesized and anchored onto the perylene diimide (PDI) core at the -bay position (PHI). PHI has been explored for the generation of radical anions (PH1˙-) and dianions (PH12-) in 20% HEPES buffer-DMSO solution using H2S as a sacrificial electron donor. The PH1˙- has a half-life (t1/2) of 1.5 h and 3 h in oxygenated and hypoxic conditions, respectively. The formation of radical anions has been confirmed by optical (absorbance and fluorescence) methods, cyclic voltammetry (CV), differential pulse voltammetry (DPV), and femtosecond transient absorbance spectroscopy along with current-voltage (I-V) and NOBF4 studies. The PH1˙- showed peroxidase-like activity for the reduction of H2O2 as low as 170 fmol L-1 (fM) giving a colour change from sea green to pink. The biochemical assay which consists of PH1˙-+ GOx has been further utilized as a glucose sensor. Upon addition of glucose (0-8 nM) in the biochemical assay, the in-situ produced H2O2 (after oxidation of glucose with GOx) oxidized PH1˙- to PH1 giving a sea green to pink colorimetric read out along with a decrease in the absorption intensities at 720, 815, 880 and 950 nm and the emergence of absorption intensity at 541 nm. The lowest limit of detection is 85 fM. We also explored this biochemical assay for the detection of 860 fM of glucose in a 10% blood serum. Similarly, fluorometric, CV and DPV studies were carried out for the detection of glucose using this biochemical assay. The smartphone-assisted RGB colour analyser showed large variations in the red colour and this RGB based colour differentiation can be used for the detection of 1 nM of glucose.

Theoretical and Experimental Analyses of the Interfacial Mechanism of Dendrimer-Doxorubicin Complexes Formation.

The work presents correlations between the physicochemical properties of the carrier and the active substance and optimization of the conditions for creating an active system based on PAMAM dendrimers and doxorubicin. The study monitored the influence of the ionized form of the doxorubicin molecule on the efficiency of complex formation. The deprotonated form of doxorubicin occurs under basic conditions in the pH range of 9.0-10.0. In the presence of doxorubicin, changes in the zeta potential of the complex concerning the initial system are observed. These changes result from electrostatic interactions between the drug molecules and external functional groups. Based on changes in the absorbance intensity of UV-vis spectra, the binding of the drug in the polymer structure is observed depending on the pH of the environment and the molar ratio. Optimal conditions for forming complexes occur under alkaline conditions. UV-vis, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy confirmed the stability of the formed dendrimer-DOX complex. Molecular dynamics simulations were conducted to gain a deeper insight into the molecular mechanism of DOX adsorption on and within the G4.0 PAMAM dendrimers. It was observed that the protonation state of both the dendrimer and DOX significantly influences the adsorption stability. The system exhibited high stability at high pH values (∼9-10), with DOX molecules strongly adsorbed on the dendrimer surface and partially within its bulk. However, under lower pH conditions, a reduction in adsorption strength was observed, leading to the detachment of DOX clusters from the dendrimer structure.

Mechanically Stable PMMA‐Based Large‐Area Nano‐Channels with Sub‐10 nm Depth

AbstractArtificial sub‐microfluidic and nanofluidic devices allow for studying mass or ion transport effects under spatial confinement. It remains challenging to fabricate large‐scale, nanofluidic channels of well‐defined thickness for fundamental studies and practical applications, especially for extreme confinement conditions (e.g., with sub‐10 nm channel height). Here, a strategy is reported to fabricate large‐scale nano‐channels with the channel height down to 5.0 nm. The fabrication is enabled by developing ultra‐flat and ultra‐thin polymethylmethaacrylate (PMMA) layers as the spacer. The ease of scaling up the channel length to a millimeter in the lateral dimensions with high mechanical stability is demonstrated. Furthermore, experimental evidence is provided of the role of the mechanical coupling between the spacer and capping materials in determining the device's mechanical properties, and how controlling the channel width and the top graphite thickness can be employed to tailor the device's mechanical properties. Finally, employing near‐field IR experiments, the decay constant is established for the near‐field absorption intensity of PMMA molecules inside the channel by increasing the top layer thickness. This work develops a novel method for fabricating large‐area, mechanically stable nano‐channels for nanofluidic devices and lays the foundation for further in situ spectroscopic studies of electrochemistry within sub‐10 nm confinement.