Nature encodes stability and responsiveness within single-molecule frameworks, creating systems that remain structurally persistent while retaining access to activated functional states. Tetrazoles embody this principle in synthetic chemistry by combining aromatic persistence with latent reactivity within a single nitrogen-rich heterocycle. Their intrinsic "Jekyll-Hyde" duality arises from a polarized electronic structure governed by the substitution pattern, which acts as an electronic switch between adaptive, triggerable, and structurally persistent regimes. Although tetrazoles are widely used in small-molecule chemistry, they remain comparatively underexplored as electronically programmable motifs in polymer science. Their polarity, ion-binding ability, and photoreactivity are often exploited individually rather than integrated into a broader structure-function framework. This Minireview presents a unifying concept linking tetrazole substitution patterns to electronic identity and, consequently, to macromolecular function in polymer systems. Monosubstituted tetrazoles enable adaptive acid-base responsiveness, hydrogen bonding, and ionic network formation. In contrast, 2,5-disubstituted tetrazoles serve as photoaddressable precursors for nitrile imine-mediated ligation, covalent fixation, and fluorescent readout, whereas regio-defined 1,5-disubstituted tetrazoles provide electronically locked, highly polar heteroaromatic motifs for persistent polymer architectures. Thus, the mini-review examines how synthetic strategy governs the formation and preservation of these substitution-defined tetrazole motifs during polymer synthesis, establishing practical design principles for rational development of functional polymer materials.
The effect of Si/Al ratio and nature of the silicon-substituting element (Fe, Ga, B) on acidic and catalytic properties of BEA zeolites in glycerol conversion at 300-340 °C was investigated. Physicochemical and structural characteristics obtained by X-ray diffraction (XRD), BET, SEM, FTIR spectroscopy, MAS NMR, and Raman spectroscopy have been described and discussed. An increase in Si/Al ratio reduces both Brønsted (BAS) and Lewis (LAS) acid site concentrations, thereby decreasing the total acidity of zeolites. In HAlSiBEA samples, the BAS/LAS ratio correlates with the proportion of tetrahedrally coordinated aluminum (AlIV) to pentahedrally coordinated aluminum (AlV), indicating that BAS is associated with AlIV, while LAS is predominantly associated with AlV. The nature of the silicon substitution element determines HESiBEA overall acidity via changing strong sites concentration: HBSiBEA < HFeSiBEA < HAlSiBEA < HGaSiBEA. Glycerol conversion products over all catalysts are acetaldehyde and acrolein. Both the Si/Al ratio and the nature of the silicon-substituting element have a greater effect on overall catalytic activity than on product distribution. Acrolein yield for HESiBEA catalysts depends on total acidity, and acetaldehyde yield increases with LAS/BAS ratio. Acetaldehyde selectivity tends to increase with temperature, while acrolein selectivity decreases. Studies show that variation of the elements isomorphically introduced into the BEA zeolites structure is a more effective tool for increasing their catalytic activity than dealumination of aluminosilicate HAlSiBEA. Moreover, isomorphously substituted HESiBEA catalysts are less prone to surface carbonization during catalysis than HAlSiBEA. These findings provide new insights into the structure-activity relationships of BEA-type zeolites, offering guidance for the rational design of catalysts for glycerol valorization.
Snakebite maims or kills several hundred thousand people each year. For more than a century, treatment has relied on antivenoms derived from animals immunized with whole venoms, but their efficacy, safety, and availability are highly variable, and it is often not well understood which specific venom components must be inhibited to prevent mortality and major morbidities. New therapeutic approaches are needed. Here, we take an evolutionary approach to antivenom design inspired by the longstanding observation that vipers have evolved serum-borne toxin inhibitors that confer resistance to their own venoms. We have investigated the abilities of a family of four rattlesnake metalloproteinase (MP) inhibitors derived from the ancestral serum glycoprotein Fetuin-A (FETUAs) to neutralize the enzymatic, hemorrhagic, and lethal activities of viper venoms. We find that while certain individual FETUA proteins are able to inhibit enzymatic or hemorrhagic activity, they are unable or only partially able to inhibit venom lethality. However, we show that specific combinations of FETUA proteins complement one another's activities and are sufficient to fully neutralize rattlesnake venom lethality with approximately 10 times greater potency than commercial antivenom. Moreover, we demonstrate that FETUA proteins are well conserved among viper subfamilies and that rattlesnake FETUAs are able to inhibit the MPs and neutralize the lethality of several evolutionarily distant pit viper or true viper venoms. Our results highlight the critical importance of inhibiting MPs in hemorrhagic venoms and the potential general utility of combinations of naturally evolved, recombinant MP inhibitors in the treatment of viper snakebite.
Achieving kinetic stability of hydrolytically labile bonds remains a persistent goal of chemistry. The present study investigates the kinetic stability of boron-heteroatom bonds in N-methyliminodiacetic acid (MIDA) boronates. The hemilabile nature of the ligand has enabled the synthesis of molecules that would otherwise be considered too hydrolytically labile. Depending on the structure, acid-promoted migration of the boryl substituent was found to produce molecules with boron bound to nitrogen in different oxidation states. The formation of azidoboronate over aminoboronate is a particularly interesting consequence of kinetic stabilization and is at odds with the expectedly low-energy path to nitrogen gas elimination. By focusing on the unusual stability of boron-heteroatom bonds in different settings, this study contributes to the development of fundamental aspects of organoboron chemistry and offers a path to versatile building blocks that should find widespread utility in chemistry.
Alzheimer's disease (AD) is characterized by progressive cognitive decline and stereotyped neuropathology, yet the earliest cellular events that precede overt plaque burden and measurable behavioral impairment remain incompletely defined. Here, we tested the hypothesis that synaptic hyperexcitability and subcellular metabolic dysfunction emerge early in the 5xFAD mouse model and contribute to region-specific neuronal vulnerability before substantial amyloid plaque deposition. Using the 5xFAD heterozygous mouse, we first established the onset of transgene expression and the timing of plaque accumulation. Robust transgene expression was detected by postnatal day 15 and statistically significant plaque accumulation in the CA1 stratum radiatum by 4 months of age. Hippocampal slice electrophysiology revealed an early hyperexcitable phenotype at 1 month of age, including both increased AMPA receptor-mediated transmission and N-methyl-D-aspartate receptor signaling associated with the GluN2B subunit. Given the tight coupling between glutamatergic hyperactivity, oxidative stress, calcium dysregulation, and mitochondrial health, we assessed mitochondrial structure and function at this pre-plaque stage. Mitochondrial abnormalities consistent with impaired bioenergetic homeostasis were evident within hippocampal synaptic processes. Morphological analyses demonstrated that these early changes were associated with altered dendritic architecture in the CA1 and dentate gyrus regions, revealing hippocampal subregional susceptibility. Finally, spatial transcriptomics identified regionally enriched molecular signatures consistent with differential vulnerability. The CA1 subregion exhibited pronounced downregulation of mitochondria-related transcripts, and single-cell deconvolution resolved this transcriptomic suppression specifically to CA1 pyramidal neurons (CA1.ProS); CA3 and dentate gyrus did not show equivalent mitochondrial pathway suppression. Together, these findings define a pre-plaque window in 5xFAD mice marked by GluN2B-linked glutamatergic hyperexcitability, early mitochondrial disruption, and selective dendritic and transcriptional vulnerability. Mitochondrial transcriptomic suppression was anatomically restricted to CA1 pyramidal neurons, establishing a cell-type-specific bioenergetic signature at 1 month of age, well before overt amyloid pathology. While the observations herein are descriptive in nature and detailed mechanisms have yet to be established, nevertheless, the integrated timeline suggests that synaptic and metabolic dysfunctions arise before substantial plaque deposition and may represent tractable early targets for intervention in AD.
Developing enzymatic mechanisms for C-F bond formation remains a long-standing challenge. Here, we repurposed the biosynthetic nonheme Fe enzyme EgtB, which features a three-histidine facial triad, to catalyze C(sp 3 )-H fluorination reactions. Directed evolution of EgtB afforded two new-to-nature fluorine atom transferases with opposite enantiopreference, EgtB CHF1 and EgtB CHF2 , with up to 28-fold improved total activity. In contrast to our previously evolved nonheme Fe fluorine atom transfer biocatalyst ACCO CHF , which contains a two-histidine-one-carboxylate facial triad, the evolved EgtB CHF variants displayed unexpected hydroxylation activity. 18 O-labeling experiments showed that the hydroxy group originated from water rather than residual O 2 . Computational studies suggested that the three-histidine-supported Fe(III) center exhibits enhanced Lewis acidity compared to the two-histidine-one-carboxylate system, allowing deprotonation of Fe(III)-bound water to form a Fe(III)-OH species to catalyze radical hydroxylation. Primary coordination-sphere mutagenesis in EgtB and ACCO further supported the critical role of Fe coordination chemistry in controlling radical rebound reactivity and selectivity. Computational studies revealed that Fe coordination chemistry strongly influences both fluorine atom abstraction and radical rebound, with the intrinsic C-X (X = F, OH, and N 3 ) bond forming radical rebound preference following the order N 3 > OH > F. Furthermore, multivariate linear regression analysis revealed that fluorine atom abstraction is primarily governed by the intrinsic Fe-F bond strength, whereas fluorine rebound is predominantly controlled by the electronic structure of the Fe(III) intermediate. Together, these findings provide mechanistic insights into nonheme Fe enzymology and reprogramming toward selective radical rebound reactions, including challenging C-H fluorination.
Living cell-based computers are in their infancy and answering multiple computational decision problems by a single system remains a key challenge. Here, we demonstrate an artificial neural network type architecture implemented with molecular-genetically engineered bacteria that answer four computational decision problems by identifying four types of prime numbers, including cluster prime, Euclid prime, safe prime, and Lucas prime, within the range of 0-9 in a chemical space. First, we demonstrated that the network consisting of four engineered cells classified two prime number families, namely cluster and Lucas prime numbers. Next, we scaled up the four-cell network to a six-cell network by introducing two new engineered cells and demonstrated that the new network classified four prime number families. Questions were asked to the bacteria by applying chemicals in binary patterns, and the answers were obtained from the distinct expression patterns of multiple fluorescent proteins. Each bacterium was engineered with synthetic gene regulatory networks such that the system chemistry followed the mathematical nature of an artificial neuro-synapse module. Collectively, the molecular-genetically engineered bacterial population formed a single-layered artificial neural network type architecture in liquid culture to perform the overall computation. The work may have implications in synthetic biology, biocomputing, and biologically implemented AI wetware.
Developing sustainable and efficient catalytic strategies to construct aryl alkyl ethers from inexpensive feedstocks remains a central objective in modern synthetic chemistry. In this context, a ligand-centered redox-controlled zinc amide system is disclosed herein that enables highly selective defluoroetherification of aryl fluorides, irrespective of their electronic nature, with diverse alcohols under mild conditions (70-80 °C, 4-8 h), for the first time. Comprehensive mechanistic studies, including radical-trapping experiments, EPR spectroscopy, HRMS analysis, and various control experiments, support a radical-mediated C-(sp2)-O cross-coupling driven by unique intramolecular electron transfer within the Zn-(II)-amide framework. Intriguingly, the protocol could engage both electron-neutral and -rich aryl fluorides that are typically unreactive under conventional S N Ar conditions and display excellent functional-group tolerance. Accordingly, selective C-F bond activation delivers F-containing aryl ethers of pharmaceutical relevance with high chemoselectivity over readily reducible, e.g., CN, NO2, CO, and CC, functional groups. Moreover, many types of alcohols (primary, secondary, aliphatic, and benzylic) are efficiently transformed within a unified manifold. The mildness and breadth of the method further enable late-stage diversification of complex, bioactive molecules, providing streamlined access to structurally convoluted ether architectures including drug derivatives. Overall, this work establishes a mechanistically distinct, operationally simple, and sustainable platform for selective aryl C-F bond functionalization that expands the toolbox of C-O bond generation.
Active polymers represent a distinct class of non-equilibrium systems whose structure and movement are strongly influenced by the nature of activity and environmental complexity. In this work, we present a comparative study of an Active Brownian Polymer Chain (ABPC) and a Tangentially Active Polymer Chain (TAPC) in a two-dimensional porous environment using Brownian dynamics simulations. Our study on two different types of active polymers reveals distinct differences in their conformational and dynamical properties. We identify fundamentally different trapping mechanisms in the two systems: ABPC exhibits extensive folding in the porous confinement, whereas TAPC adapts stable spiral conformations accounting for persistent self-trapping at moderate and high activity. Furthermore, ABPC undergoes unrestraint motion at high activity, while TAPC displays reptation-like motion at low activity, leading to efficient escape from the traps. Our findings suggest that the nature and strength of activity coupled with environment complexity lead to emergent phenomena that dictate these unique conformational and dynamical properties of active polymers.
Under microsolvent conditions, when the α-nucleophile HOO- reacts with CH3Br, it can abstract a proton from the solvent CH3OH to induce alternative nucleophile CH3O-(HOOH). In the present work, the competition between the normal HOO--SN2 pathway and the photon transfer (PT)-induced CH3O--SN2 pathway has been explored by quantum chemistry calculations for HOO-(CH3OH) n and CH3O-(HOOH)0,1 (CH3OH) n-1 reacting with CH3Br. The potential energy profile of the HOO--SN2 pathway exhibits that the energy barriers of the traditional back-side attack substitution are 0.4-3.8 kcal/mol lower than those of the CH3O--SN2 pathway, suggesting the HOO-(CH3OH) n is more active, which is consistent with the experimental phenomenon. The activation strain analysis suggests compared to the CH3O--SN2 pathway, the stronger interaction energy between the HOO-(CH3OH) and CH3Br over the entire reaction course stabilizes its transition state, which is caused by the stronger orbital interaction of the HOO--SN2 pathway. The barrier heights of both pathways are increased with the incremental hydration, but the PT-induced CH3O--SN2 pathway is highly suppressed. The enhanced reactivity of reactions involving HOO-(CH3OH) n is found through comparison with CH3O-(HOOH)0,1(CH3OH) n-1 nucleophiles and is ascribed to the α-nucleophilic character of the HOO- anion. This work deepens an understanding of the nature of the α-effect nucleophile and highlights the effect of the solvent molecule on the enhanced reactivity.
Curved conjugated molecules with strained non-planar geometries show unique properties valuable for supramolecular chemistry and optoelectronics, but their synthesis and modification remain challenging. We introduce carbazole-embedded cycloparaphenylenes (CPPs) as versatile building blocks to overcome these limitations. Using Suzuki coupling and regioselective bromination, we created a functionalizable macrocyclic synthon. This enabled controlled multi-component couplings to construct trimacrocyclic (TMC) and pentamacrocyclic (PMC) curved π-systems. Structural analyses reveal TMC adopts a well-defined C-shape that self-assembles into tubes, while PMC shows a deformed conformation. Their optical and electronic properties are size-dependent, featuring strong fluorescence and stepwise oxidation to open-shell polycations. Supramolecular studies show TMC acts as an adaptive host, forming distinct 1:1 complexes with C60 (host-guest recognition-induced host cavity expansion) and C70 (encapsulation without conformational change). In comparison, PMC forms 2:1 (guest:host) complexes with C60 or C70. Crystallographic and computational data indicate recognition is governed by the geometrically defined C-shaped cavity rather than the macrocycle's electron-rich nature.
Body temperature is a key physiological indicator, requiring continuous, full-range monitoring from normothermia to hyperthermia for effective heatstroke management. To address the limitations of mercury thermometers and existing sensors in visualized real-time screening, three monomers S-1, S-2, and S-3 featuring flexible aliphatic chains and ester terminals, anhydride terminals, and aromatic rings with amide hydrogen bonds and π-π stacking are designed and polymerized into Poly(S-1), Poly(S-2), and Poly(S-3), respectively. Among these polydiacetylenes (PDAs) with symmetric functionalization, Poly(S-1) exhibits a multi-step, naked-eye-visible thermochromic transition within 35°C-43°C, attributed to its flexible aliphatic chains and ester linkages that enable side-chain motion and main-chain conformational changes at low temperatures. In contrast, the rigid structural motifs present in Poly(S-2) and Poly(S-3) introduce stronger intermolecular forces and higher energy barriers, necessitating elevated temperatures to induce comparable thermochromic transitions. Notably, Poly(S-1) is successfully fabricated into a functional patch; its irreversible thermochromic nature within the physiological range meets the requirements of disposable medical devices, helping to prevent cross-infection and facilitating temperature recording. This study enables precise tuning of the thermochromic temperature of PDA materials, expands their applications in biomedical monitoring and smart responsive materials, and offers design insights and theoretical foundations for developing next-generation visual body temperature sensors.
Direct structural characterization of reactive intermediates in photocatalytic N2 reduction is challenging due to their low concentration and fleeting nature, often limiting mechanistic understanding to spectroscopic or computational inference. Herein, we report the crystallographic capture of a coordinatively unsaturated dinuclear intermediate for N2 activation, generated through a photoinduced single-crystal-to-single-crystal transformation within a dynamic coordination polymer. The initial structure, NJUZ-Zn, is an active photocatalyst for N2 photoreduction and contains a stable [Zn2+-(N≡N)--Zn2+] site with bridging N2 - anions. Upon irradiation, N2 - dissociation was observed by single-crystal X-ray diffraction, yielding the unsaturated [Zn2+···Zn+] center. Raman spectroscopy and isotope-tracking experiments demonstrated the reversible exchange of 14N2 and 15N2 at the bimetallic site, confirming dynamic interconversion between saturated and unsaturated states during photocatalysis. Together, these results establish a photocatalytic mechanism in which dissociation of bridging N2 - generates reactive bimetallic intermediates that continuously capture and activate external N2 to produce ammonia under ambient conditions. This work provides unambiguous structural evidence of a key intermediate in an active photocatalyst for N2 fixation, offering a blueprint for understanding the reaction pathway and guiding the rational design of cooperative metal sites for sustainable catalysis.
This study demonstrates the utility of the electrochemical-surface force balance (e-SFB) for observing solid electrolyte interphase (SEI) formation directly at an electrode surface. Through proof-of-concept measurements of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) based electrolytes, absolute thickness and mechanical properties of SEIs are measured in situ before and after electrochemical cycling. The SEIs that formed in these systems were found to have thickness on the order of 100s of nm and elastic moduli on the order of 10s of MPa depending on cycling conditions and the nature of the solvent.
The adaptable nature of Escherichia coli, shifting from benign to virulent forms, poses a major healthcare challenge due to rising multidrug resistance and hypervirulence. In this study, using an in silico reverse vaccinology approach, we designed a multiepitope mRNA vaccine candidate targeting the Shiga toxin 1 (Stx1) of Shiga toxin-producing E. coli (STEC). Two cytotoxic T-Lymphocyte (CTL), three Helper T-Lymphocyte (HTL), and two Linear B-Lymphocyte (LBL) epitopes were identified and selected through stringent computational filtering based on high antigenicity, non-allergenicity, and non-toxicity. These epitopes were joined using optimized linkers (EAAK, AAY, GPGPG, KK) and the adjuvant PefE to form a stable 184-residue multi-epitope construct. Physicochemical profiling predicted a molecular weight of 19969.45 Da, an antigenicity score of 0.9278 (VaxiJen v.2.0), a basic isoelectric point (pI) of 10.31, and structural stability. Structural analysis revealed 21.74% alpha-helical content. Molecular docking exhibited strong binding with human Toll-like receptor 2 TLR2 and TLR4, with weighted energy scores of - 1096.2 and - 1110.5 kcal/mol, respectively, mediated by extensive hydrogen-bonding and salt-bridge networks. In silico immune simulation projected a strong clonal expansion of B-cells, active T-helper and cytotoxic T-cells, and higher cytokine production (IFN-γ, IL-10). Codon Adaptation Index (CAI) of 0.87 and a stable mRNA secondary structure were predicted with a minimum free energy (MFE) of - 204.10 kcal/mol. While these computational findings provide immunogenic potential, they represent a predictive hypothesis. Subsequent in vitro synthesis and in vivo testing in animal models are essential to validate its safety, immunogenicity, and protective efficacy.
Organic thermally activated delayed fluorescence (TADF) materials, capable of harvesting both singlet and triplet excitons to achieve a theoretic internal quantum yield of 100%, have exhibited promising applications in a wide-range of fields. However, most of them suffer from a large singlet-triplet energy gap (ΔEST) and a slow reverse intersystem coupling rate. Herein, using two N-heterocyclic benzimidazole derivatives as carbon source, two binary composites (R1-CDs@B2O3 and R2-CDs@B2O3) with uniformly dispersed N-doped carbon dots (N-CDs) in a hydroxyl-functionalized boric oxide matrix, were successfully fabricated. Benefiting from sufficiently small ΔEST (0.07 and 0.15 eV) and oxygen defect-assisted exciton recombination, these materials emit intense deep-blue TADF emission under ambient conditions, featuring ultralong lifetimes exceeding 2.53 s, high photoluminescence quantum yields (PLQY) up to 70.7% and durable afterglow lasting more than 27 s. R2-CDs@B2O3 with more carbonyl groups anchored on the carbon core achieves improved lifetime and PLQY via enhanced spin-orbit coupling. A high-efficiency white-light-emitting ternary composite was constructed through singlet-singlet energy transfer. Owing to their high PLQY, tunable emission and naked eye-visible afterglow, these materials were intriguingly used in dynamic display of polychrome three-dimensional artworks and multi-level information anti-counterfeiting and encryption. In particular, the developed epoxy matrix encapsulation strategy for improving the long-term stability of the composites significantly overcomes the practical limitations arising from the hygroscopic nature of the B2O3 matrix.
The rapid spread of metallo-β-lactamase (MBL)-mediated resistance, particularly by NDM- and VIM-type enzymes, poses a major threat to the clinical efficacy of β-lactam antibiotics. Building on our previous work, we report the design, synthesis, and evaluation of 4-substituted 3,5-diarylpyrrole-2-carboxylic acids as MBL inhibitors. Structure-activity relationship studies revealed that both the nature and position of substituents in the A and B rings, as well as functionalization at the C4 position, critically influence inhibitory activity. Notably, C4 halogenation, especially bromination, significantly enhanced inhibition of VIM-2 while maintaining activity against NDM-1. Molecular modelling supported these findings, indicating distinct binding modes and coordination patterns within the enzyme active sites. The most active compounds displayed nanomolar potency and effectively restored the activity of β-lactam antibiotics, including meropenem, against NDM- and VIM-producing resistant strains. Importantly, the compounds exhibited no detectable cytotoxicity and lacked intrinsic antibacterial activity. These results identify C4-functionalized pyrrole-2-carboxylic acids as promising dual-target MBL inhibitors for combination antibacterial therapy.
Biarylitides are a group of bacterial ribosomally synthesized and post-translationally modified peptides (RiPPs) that contain a biaryl bridge formed by dedicated cytochrome P450 enzymes that can introduce different cross-links. The biarylitides are produced via a five-amino-acid precursor peptide, encoded by a minimal 18 bp gene that evades automatic detection. Previous genome mining approaches for biarylitides do not capture their full biosynthetic space. We therefore repurposed a machine learning algorithm to comprehensively chart the biosynthetic space of the biarylitides, including variation of precursor motifs, P450, and additional modifying enzymes, which yielded 277 biarylitide biosynthetic gene clusters (BGCs). We experimentally investigated biaryl formation with previously uninvestigated core peptide motifs, including YWH, YVH, and YWY, and elucidated the nature of these cross-links. This study significantly expands the biarylitide precursor and BGC diversity and provides directions for the systematic exploration of other RiPP families.
Semiconductor metal oxides, particularly zinc oxide (ZnO) and copper oxide (CuO), have attracted considerable attention as photocatalysts for the degradation of organic pollutants because of their favorable electronic properties, chemical stability, and low cost. In this study, ZnO and CuO nanoparticles were synthesized by wick-assisted solution combustion, while Zn-Cu mixed oxide composites were prepared by thermal decomposition of oxalate precursors. Their structural, morphological, and photocatalytic properties were systematically compared with those of commercial materials. X-ray diffraction analysis showed that the synthesized ZnO possessed a highly crystalline hexagonal wurtzite structure, whereas the commercial ZnO exhibited a predominantly amorphous nature. The photocatalytic activity was evaluated by the degradation of Orange G dye under UV irradiation. Commercial ZnO exhibited superior photocatalytic performance compared with the synthesized ZnO, while the synthesized CuO showed enhanced activity relative to commercial CuO. The Zn-Cu mixed oxide composite demonstrated improved photocatalytic performance owing to the synergistic interaction between ZnO and CuO, which promotes charge separation and suppresses electron-hole recombination. Electron paramagnetic resonance (EPR) spectroscopy confirmed the generation of hydroxyl (˙OH) and superoxide (˙O2 -) radicals during UV irradiation, and radical trapping experiments identified ˙OH as the dominant reactive species responsible for Orange G degradation. These findings provide direct experimental evidence for the proposed photocatalytic mechanism and establish a clear relationship between crystallinity, reactive oxygen species generation, and photocatalytic performance. The results provide useful insights into the design of efficient ZnO-CuO-based photocatalysts for environmental remediation applications.
Bruxism-induced wear and microbial colonization of oral splints remain significant challenges in restorative dentistry. In this study, we developed a series of antibacterial nanocomposites based on a poly(ethylene terephthalate-co-1,4-cyclohexanedimethylene terephthalate) (PET-G) matrix incorporated with zinc oxide (ZnO) particles (3, 7, and 10 wt%), designed for the next generation of oral appliances. The composites were fabricated via a solvent-casting method followed by thermal processing. Differential scanning calorimetry (DSC) revealed that the amorphous nature and glass transition temperature (Tg ≈ 80 °C) of the PET-G matrix remained stable, ensuring excellent processability. While a minor decrease in Shore D hardness and flexural strength (up to 15%) was observed due to filler-induced structural discontinuity, the mechanical integrity remained within clinically acceptable limits. Crucially, the PET-G/ZnO composites exhibited potent antimicrobial activity; the 7 and 10 wt% loadings achieved a 100% reduction in Streptococcus oralis viability and significant inhibition of Candida albicans. These findings demonstrate that ZnO integration provides a dual-functional advantage-maintaining the thermoplastic versatility of PET-G while introducing critical bioactive properties, positioning these materials as a superior alternative for effective long-term bruxism therapy.