Substrate Oxidation Research Articles

Running in the heat similarly reduces lipid oxidation and peak oxygen consumption in trained runners and inactive individuals.

This study compared oxygen consumption and substrate oxidation while exercising in hot and temperate conditions in individuals with different physical activity status (i.e., inactive individuals vs. trained runners). 10 inactive individuals (IA: 26 ± 6 y; 79.1 ± 14.1 kg; 40.7 ± 5.1 ml·kg-1·min-1) and 10 trained runners (TR: 25 ± 6 y; 69.5 ± 9.1 kg; 63.1 ± 5.1 ml·kg-1·min-1) completed two incremental exercise tests (4 min stages) until exhaustion in temperate (TEMP: 18.7 ± 0.1 °C; 43.2 ± 4.1% relative humidity) and hot (HOT: 34.4 ± 0.2 °C and 42.6 ± 1.6% relative humidity) conditions. Expired gas and blood lactate concentrations were measured at the end of each stage. Peak oxygen consumption similarly decreased in HOT compared to TEMP for IA and TR (-13.2 ± 4.5% vs. -15.2 ± 7%; p=0.571; ES=0.25). In HOT compared to TEMP, lipid oxidation, from 30 to 70% of V̇O2peak, was reduced for both groups (IA: p=0.023, ES=0.43; TR: p<0.001, ES=0.72) while carbohydrate oxidation was increased for TR (p=0.011; ES=0.45) but not for IA (p=0.268; ES=0.21). Core temperature was different between conditions for TR (higher in HOT, p=0.017; ES=0.66) but not for IA (p=0.901; ES=0.25). Despite reduced physiological capacities in IA, both populations demonstrated reductions in lipid utilisation and peak oxygen consumption in hot compared to temperate conditions. However, the increased carbohydrate oxidation in HOT for TR were not observed in IA, potentially explained by lower thermal strain.

Development of an integrated micro-millisystem for continuous laccase extraction.

Efforts to reduce the impact of chemical processes on the environment are leading to a shift to enzymatic alternatives, with laccases standing out for their versatile substrate oxidation capabilities. This study addresses the improvement of biocatalytic reactions by deep eutectic solvents (DES), in particular DES-based aqueous two-phase systems (ATPS) for the extraction of biomolecules. Continuous laccase extraction from crude samples was achieved using a DES-based ATPS, which was first optimized in a batch extractor and later intensified in a microextractor. Integration with a milliseparator enabled continuous phase separation, which increased process efficiency. The extracted laccase used as a co-solvent showed superior efficiency in the degradation of aniline dyes. This research not only advances enzyme extraction methods, but also highlights the potential of laccase in sustainable biocatalytic processes, particularly in environmental remediation.

Standing or Very Low-Intensity Cycling as Sedentary Breaks: Does Physical Activity Level Matter?

Active breaks and very low- to low-intensity exercises such as walking or cycling at an active desk have been shown to significantly counteract the negative effect of prolonged sedentary behaviors. The objective was to investigate the effect of physical activity level(PAL) on changes in energy expenditure (EE), heart rate, and substrate oxidation from sit-to-stand and sit-to-light cycling. Fifty healthy young males and females (age: 23.9 [3.9]y, body mass index: 22.9 [2.3]kg/m2) were submitted to a fixed 1hour session of different posture allocations: 15-minute sitting, 15-minute standing, 15-minute sitting, and 15-minute very low-intensity cycling. EE, substrate oxidation rates, and heart rate were continuously assessed throughout the experimental visit. Data were then compared between participants according to their PALin tertiles (low, medium, or high). The high-PAL group showed lower sedentary time (P < .0001) and higher time spent in low (P < .0001), moderate (P < .0001), and vigorous physical activity (P = .0034). ANOVA's analysis showed that EE significantly increased when standing (+11%) and cycling (+94%) relative to the seated position (P < .05) without any differences between groups. There was also a significant increase in heart rate during standing and cycling compared with sitting (P < .05) without any differences between groups. Relative EE (in kilocalories per minute per kilogram) was significantly higher when seated (P < .05) independent of PAL but marginally higher in the high-PAL group when standing relative to the medium-PAL group (P = .06). The findings of this study suggest that people's PAL does not impact energetic and metabolic adaptations during sit-to-stand and sit-to-very-light-intensity cycling exercise.

Acidic Engineering on Buried Interface toward Efficient Inorganic CsPbI3 Perovskite Light-Emitting Diodes.

Inorganic CsPbI3 perovskite has emerged as a promising emitter for deep-red light-emitting diodes (LEDs) due to its intrinsic thermal stability and suitable bandgap. However, uncontrollable CsPbI3 crystallization induced by an alkaline zinc oxide (ZnO) substrate in bulk film-based LEDs leads to insufficient external quantum efficiencies (EQEs) at high brightness, leaving obstacles in commercialization progress. Herein, we demonstrate an effective acidic engineering strategy with wide applicability to modify the surface property of ZnO and regulate CsPbI3 crystallization. Via systematically selecting 1,4-cyclohexanedicarboxylic acid with a mild acid dissociation constant to functionalize the buried interface, we mitigate the speed of the deprotonation reaction and achieve homogeneous CsPbI3 films with high phase purity and fewer defects. The resulting CsPbI3 perovskite LEDs (PeLEDs) exhibit a record EQE of 19.4% at a high luminance of 3400 cd m-2, representing the state-of-art bulk CsPbI3 PeLEDs. These findings provide valuable insights in the advancement of efficient CsPbI3 PeLEDs.

Assays to Enhance Metabolic Phenotyping in the Kidney.

The kidney is highly metabolically active, and injury induces changes in metabolism that can impact repair and fibrosis progression. Changes in expression of metabolism-related genes and proteins provide valuable data, but functional metabolic assays are critical to confirm changes in metabolic activity. Stable isotope metabolomics are the gold standard, but these involve considerable cost and specialized expertise. Both the Seahorse bioflux assays and substrate oxidation assays in tissues ex vivo are two relatively cost-effective assays for interrogating metabolism. Many institutions have access to Seahorse bioflux analyzers, which can easily and quickly generate data, but guidelines to enhance reproducibility are lacking. We investigate how variables (e.g. primary versus immortalized cells, time in culture) impact the data generated by Seahorse bioflux analyzers. In addition, we show the utility of 3H-palmitate, a new approach for assessing fatty acid oxidation in the kidney, in uninjured and injured kidney cortices. The 3H-palmitate substrate oxidation assays also demonstrate significant sex-dependent and strain-dependent differences in rates of fatty acid oxidation. These data should facilitate metabolic interrogation in the kidney field with enhanced reproducibility.

Carbohydrate supplementation maintains physical performance during short-term energy deficit despite reductions in exogenous glucose oxidation.

Exogenous glucose oxidation is reduced 55% during aerobic exercise after three days of complete starvation. Whether energy deficits more commonly experienced by athletes and military personnel similarly affect exogenous glucose oxidation and what impact this has on physical performance remains undetermined. This randomized, longitudinal parallel study aimed to assess the effects of varying magnitudes of energy deficit (DEF) on exogenous glucoseoxidation and physical performance compared to energy balance (BAL). Participants consumed a4-day BAL diet, followed by a 6-day 20% (n=10), 40% (n=10), or 60% (n=10) DEF diet. At the end of each energy phase participants performed 90-min of steady-state cycle ergometry (56±3% V̇O2peak) while consuming a glucose drink (80 g), followed by a time to exhaustion (TTE) performance test. Substrate oxidation (g/min) was determined by indirect calorimetry and 13C glucose. Muscle glycogen (mmol/kg dry weight) and transcript accumulation were assessed in rested fasted muscle collected before exercise in each phase. Muscle glycogen was lower (P = 0.002) during DEF (365±179) than BAL (456±125), regardless of group. Transcriptional regulation of glucose uptake (GLUT4italic> and IRS2) and glycogenolysis (HKII and PKM) were lower (P < 0.05) during DEF than BAL, independent of group. Regardless of group, exogenous glucose oxidation was 10% lower (P < 0.001) during DEF (0.38±0.08) than BAL (0.42±0.08). There was no evidence of a difference in TTE between BAL and DEF or between groups. In conclusion, despite modest reduction in exogenous glucose oxidative capacity during energy deficit, physical performance was similar compared with balance.

Oxygen-modulated photoresponse in nickel oxide thin films for wide band gap photodetector application

Metal oxides, due to their wide band gap, are well suited for use in photodetectors as the active light-absorbing layer. While there have been extensive studies on n-type oxides, such as tungsten oxide and zinc oxide, there is relatively little work on the use of p-type oxides, such as nickel oxide (NiO), for photodetectors. Using these p-type oxides along with n-type conducting oxides to form heterojunctions can improve the detection capabilities by efficient separation of charge carriers. In this work, the photoresponse of a p-type NiO thin film, grown by room temperature reactive magnetron sputtering from a pure nickel target onto a conducting n-type indium-doped tin oxide (ITO) substrate, is investigated. Different ratios of oxygen to argon (10/45, 15/45, and 20/45) during sputtering are investigated, and the effect of oxygen concentration on the optical properties of the NiO film is studied, which helps in modulating the photoresponse of the developed detector. The O2/Ar ratio, with a value of 15/45, is found to perform better among the three ratios. For the corresponding photodetector, the current under illumination, is found to be nearly three orders of magnitude higher than the dark current, even at a very low applied voltage of 0.1 V. The calculated responsivity (at 0.012 A/W) is found to be the best among all three values. The device also has an excellent transient current response with a rise time of 0.5 s and a decay time of 1.4 s, which is the fastest transient behavior among all three ratio-based devices. The work paves the way for using metal oxide-based heterojunctions as wide band gap photodetectors.

Binding Kinetics of Self-Assembled Monolayers of Fluorinated Phosphate Ester on Metal Oxides for Underwater Aerophilicity.

The term "aerophilic surface" is used to describe superhydrophobic surfaces in the Cassie-Baxter wetting state that can trap air underwater. To create aerophilic surfaces, it is essential to achieve a synergy between a low surface energy coating and substrate surface roughness. While a variety of techniques have been established to create surface roughness, the development of rapid, scalable, low-cost, waste-free, efficient, and substrate-geometry-independent processes for depositing low surface energy coatings remains a challenge. This study demonstrates that fluorinated phosphate ester, with a surface tension as low as 15.31 mN m-1, can form a self-assembled monolayer on metal oxide substrates within seconds using a facile wet-chemical approach. X-ray photoelectron spectroscopy was used to analyze the formed self-assembled monolayers. Using nanotubular morphology as a rough substrate, we demonstrate the rapid formation of a superhydrophobic surface with a trapped air layer underwater.

Thiazolidinone-Based Electron-Collecting Monolayers for n-i-p Perovskite Solar Cells.

The development of efficient electron-collecting monolayer materials is desired to lower manufacturing costs and improve the performance of regular (negative-intrinsic-positive, n-i-p) type perovskite solar cells (PSCs). Here, we designed and synthesized four electron-collecting monolayer materials based on thiazolidinone skeletons, with different lowest-unoccupied molecular orbital (LUMO) levels (rhodanine or thiazolidinedione) and different anchoring groups to the transparent electrode (phosphonic acid or carboxylic acid). These molecules, when adsorbed on indium tin oxide (ITO) substrates, lower the work function of ITO, decreasing the energy barrier for electron extraction at the ITO/perovskite interface and improving the device performance. The shift of work function, rather than the LUMO levels of the molecules themselves, was found to be correlated with the performance of the perovskite solar cells.

Aptamer proximal enzyme cascade reactions for ultrafast detection of glucose in human blood serum.

Aninnovative colorimetric sensing strategy was developedfor the detection of glucose by the integration of glucose aptamer, glucose oxidase (GOx), and horseradish peroxidase (HRP), termed aptamer proximal enzyme cascade reactions (APECR). In the presence of glucose, aptamer binding enables GOx to catalyze glucose oxidation into H2O2 efficiently. Subsequently, the adjacent HRP catalyzes the oxidation of the peroxidase substrate, 2,2'-biazobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS2-), utilizing the generated H2O2, resulting in a distinct color change. In comparison to the free enzymes and the HRP-GOx system, APECR exhibited higher colorimetric signal. This approach achieved glucose detection within three minutes, which was significantly faster than previous methods. This method showed good sensitivity and selectivity with a limit of detection of 0.013mM. Moreover, the practical utility of this strategy was verified by achieving rapid detection of glucose in clinical serum samples. Hence, the developed strategy has the advantages of simple operation and rapid analysis time for the detection of glucose in human serum.

Direct laser writing of planar and stretchable supercapacitors based on a graphene oxide and manganese dioxide nanoparticle composite on a paper substrate

Paper-based supercapacitors (P-SCs) exhibit superior electrochemical performance owing to the flexibility and unique surface properties of paper substrates. Currently, most P-SCs adopt a sandwich structure that is limited by electrode fabrication methods. However, the development of planar paper-based devices is crucial to satisfy the tremendous demand for wearable electronics. Herein, based on the mechanism of interaction between the laser and material, we used direct laser writing (DLW) techniques to fabricate in-plane P-SCs based on graphene oxide (GO) and manganese dioxide (MnO2) composite-covered paper substrates. Owing to the in-plane device structure and pseudocapacitive MnO2, the acquired rGO-MnO2-based planar P-SCs possessed a much higher specific capacitance value (17.7 mF/cm2) than that based on sandwich-structured reduced GO (rGO) (1.71 mF/cm2). In addition, three in-series integrated devices can be easily achieved via the DLW fabrication method, which shows potential for practical applications such as powering a light emitting diode. In addition, by carefully designing the paper substrate structure, the paper-based device exhibited excellent stretching stability. A specific capacitance retention of 86.8% remained after 5000 stretch cycles. Therefore, this study provides valuable insights into the design and fabrication of wearable paper-based electronics.

An Energy Level Alignment Study of 2PACz Molecule on Perovskite Device‐Related Interfaces by Vacuum Deposition

Self‐assembling molecules (SAM) have been widely used in inverted perovskite solar cells (PSC) as a hole transfer layer due to nearly lossless charge transfer giving excellent device performance. However, the energy level alignment between SAM‐ and PSC‐related interfaces has not been systematically studied. Herein, the 2PACz, a typical SAM with the largest dipole moment, is chosen as the model system and is studied by vacuum deposition. It is found that the energy level alignment is determined by the orientation of 2PACz molecules on a different substrate. The molecules are lying down on highly oriented pyrolytic graphite and giving nearly zero interface dipole. On solvent‐cleaned and plasma‐treated indium tin oxide (ITO) substrates, the SAM is vertically assembled with 0.22 and 0.13 eV work function increases, respectively. However, on sputtered ITO, SAM is assembled with upside down orientation, with 0.51 eV work function decrease. The change of orientation is due to strong interaction between oxygen vacancies in ITO substrate and carbazole head group of 2PACz. On perovskite film, SAM also shows a slightly upward orientation with additional passivation of free MA+ ions. Herein, it is confirmed that the energy level alignment of SAM plays an important role in hole extraction.

Microbe-mediated synthesis of defect-rich CeO2 nanoparticles with oxidase-like activity for colorimetric detection of L-penicillamine and glutathione.

To enhance production efficiency, curtail costs, and minimize environmental impact, developing simple and sustainable nanozyme synthesis methods has been the focus of relevant research. In this report, graphite-coated CeO2 nanoparticles (CeO2 NPs) with multiple defects (Ce3+ defects, oxygen vacancies and carbon defects) were synthesized via the culture filtrate of the extremely radioresistant bacterium Deinococcus wulumuqiensis R12 (D. wulumuqiensis R12). The as-prepared CeO2 NPs exhibit remarkable oxidase (OXD)-like activity, efficiently catalyzing the oxidation of the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) to form oxTMB, even in the absence of H2O2. The electron-rich bioactive substances in the supernatant were demonstrated to modulate the electronic state of the Ce atom and played a key role in the formation of multiple defects, thereby enhancing the OXD-like activity of CeO2 NPs. Based on the inhibitory effect of sulphydryl groups (-SH) on the TMB-CeO2 system, a colorimetric strategy for the detection of both L-penicillamine (L-PA) and glutathione (GSH) was devised and successfully applied in real sample analysis. The linear ranges of L-PA and GSH detection were found to be 10-500 μM and 9-200 μM with the limits of detection (LODs) at 8.53 and 5.19 μM, respectively. This work provides a straightforward, eco-friendly and nontoxic method for the synthesis and defect construction of CeO2 NPs with OXD-like activity.

Sex-specific differences in insulin response and substrate oxidation after repeated, brief whole-body immersion in 45°C water: A prospective, interventional study.

Prolonged heat exposure is suggested to improve glucose metabolism and fat oxidation, but no studies have addressed whether brief heat stimuli represent a viable, time-efficient, alternative approach. Consequently, we examined the ability of brief stimuli evoked by 45°C water to improve glucose tolerance, insulin sensitivity, and fat oxidation in young, non-obese, males and females. Twenty-four participants completed fourteen 5-min sessions involving whole body passive heating in 45°C water. Changes in resting catecholamines, cytokines, substrate oxidation, resting energy expenditure, glucose tolerance, and insulin release in response to an oral glucose tolerance test, were assessed before and 24-h after intervention, and 1 month after the end of the intervention. The results showed that repeated short-duration heat intervention had no significant effects on epinephrine, norepinephrine, interleukin-6, and tumor necrosis factor alpha production in both sexes. Glucose area under the curve (AUC) was not affected. However, females had a lower insulin AUC and improved insulin sensitivity as indicated by a decrease in homeostatic model assessment for insulin resistance, and an increase in the quantitative insulin sensitivity check index and the Matsuda insulin sensitivity index values one month after the end of the heat intervention. No effect was observed in resting energy expenditure, but carbohydrate oxidation per kilogram increased in females, and this substrate oxidation change was maintained after one month. In conclusion, fourteen sessions of brief 5-min whole-body immersion in 45°C water produced an improvement in insulin sensitivity and increased reliance on carbohydrate oxidation in females.

Does mental exertion during incremental exercise change substrate oxidation and cardiorespiratory outcomes in individuals with overweight?

Given the growing concern over the impact of brain health in individuals with overweight, understanding how mental exertion (ME) during exercise affects substrate oxidation and cardiorespiratory outcomes is crucial. This study examines how ME impacts these outcomes during an incremental exercise test in adults with overweight. Seventeen adults who were overweight completed an incremental exercise test on a cycle ergometer two times, with and without the Stroop task. Energy expenditure (EE), carbohydrate and fat oxidation, maximum heart rate (HRmax), maximal oxygen uptake (VO2max), maximum fat oxidation (MFO), and the intensity of exercise that elicited MFO (Fatmax) are measured by indirect calorimetry. ME did not change the EE, carbohydrate, and fat oxidation at any stages of the incremental test. However, ME resulted in significantly lower HRmax, VO2max, and MFO (p < 0.01) and increased NASA-TLX scores but showed no change in Fatmax. These results show ME decreases the value of HRmax, VO2max, and MFO during the incremental exercise test. Due to the increased mental workload demonstrated by the NASA-TLX test, adults with overweight are unable to complete the test to the same extent as they did in the test without ME according to maximal levels in this study.

Site-specific plan-view (S)TEM sample preparation from thin films using a dual-beam FIB-SEM.

To fully evaluate the atomic structure, and associated properties of materials using transmission electron microscopy, examination of samples from three non-collinear orientations is needed. This is particularly challenging for thin films and nanoscale devices built on substrates due to limitations with plan-view sample preparation. In this work, a new method for preparation of high-quality, site-specific, plan-view TEM samples from thin-films grown on substrates, is presented and discussed. It is based on using a dual-beam focused ion beam scanning electron microscope (FIB-SEM) system. To demonstrate the method, the samples were prepared from thin films of perovskite oxide BaSnO3 grown on a SrTiO3 substrate and metal oxide IrO2 on a TiO2 substrate, ranging from 20-80 nm in thicknesses using molecular beam epitaxy. While the method is optimized for the thin films, it can be extended to other site-specific plan-view samples and devices build on wafers. Aberration-corrected STEM was used to evaluate the quality of the samples and their applicability for atomic-resolution imaging and analysis.

Blister test to measure the out-of-plane shear modulus of few-layer graphene.

We measure the out-of-plane shear modulus of few-layer graphene (FLG) by a blister test. During the test, we employed a monolayer molybdenum disulfide (MoS2) membrane stacked onto FLG wells to facilitate the separation of FLG from the silicon oxide (SiOx) substrate. Using the deflection profile of the blister, we determine an average shear modulus G of 0.97 ± 0.15 GPa, and a free energy model incorporating the interfacial shear force is developed to calculate the adhesion energy between FLG and SiOx substrate. The experimental protocol can be extended to other two-dimensional (2D) materials and layered structures (LS) made from other materials (WS2, hBN, etc.) to characterize their interlayer interactions. These results provide valuable insight into the mechanics of 2D nano devices which is important in designing more complex flexible electronic devices and nanoelectromechanical systems.

In situ oxidized Mo2CTx MXene film via electrochemical activation for smart electrochromic supercapacitors.

Mo2CTx MXenes have great potential for multifunctional energy storage applications because of their outstanding electrical conductivity, superior cycling stability, and high optical transmittance. In this study, we fabricate Mo2CTx film electrodes (referred to as Mo2C) on fluorine-doped tin oxide (FTO) substrates using the layer-by-layer (LbL) self-assembly technique. To improve the energy-storage performance of Mo2CTx film electrodes, we develop a convenient electrochemical activation process to prepare in situ oxidized Mo2CTx/MoO3 film electrodes (referred to as EA-Mo2C). The Mo2CTx/MoO3 hybrid film benefits from the addition of MoO3, which introduces extra redox sites and enhances the charge-storage capacity. Furthermore, the unique layered structure of Mo2CTx significantly reduces the diffusion energy barrier for cations. The synergistic interaction between Mo2CTx and MoO3 results in superior electrochemical performance, and the EA-Mo2C displays a remarkable increase in areal specific capacitance, achieving 23.29 mF cm-2 at a current density of 1.5mA cm-2, which is 518% higher than that of Mo2C. The electrochromic supercapacitor, assembled using EA-Mo2C as the ion-storage layer and polyaniline (PANI) as the electrochromic layer, enables power visualization and quantitative display. In summary, this study utilizes in situ electrochemical activation to derive high-performance electrode materials, offering an innovative strategy for advancing MXene-based energy-storage materials.

Effects of time-restricted feeding and meal timing on an 8-week fat oxidation exercise training program-A randomized controlled trial.

Time-restricted feeding (TRF) and aerobic exercise are lifestyle interventions to prevent or manage different metabolic diseases. How these interventions interact, including the impact of meal timing, is not well understood. The aim of this study was to examine the influence of TRF on fat oxidation during exercise, whereby participants performed an 8-week fatmax-training program either in the fasted state or after a carbohydrate-based snack. 36 participants were randomized into three groups. (1) Training sessions were performed in the fasted state; (2) Training sessions were performed after consuming a standardized carbohydrate-based snack; (3) Exercise training with an adlibitum diet as a control group. Pre- and post-tests included anthropometric measurements and a fatmax-cycle-ergometry protocol to measure substrate oxidation. Data were analyzed as workload-matched and maximal fat oxidation using a series of mixed ANOVAs. Workload-matched (p = 0.038) and maximal (p < 0.001) fat oxidation improved in all groups. No significant group × time interactions were found in substrate utilization. Time had a significant effect on body weight (p = 0.011), fat mass (p < 0.001), and muscle mass (p < 0.001). Results suggest that fatmax exercise training leads to improvements in fat oxidative capacity independent of fed or fasted state.

In situ growing of ZIF-8 crystals into TiO2 micro columnar films

This study proposes a fast and simple method for the in situ growth of metal-organic frameworks (MOFs) on metal oxide substrates as an alternative to the traditional approaches of using gold substrates and self-assembled monolayers (SAMs). As a case study, zeolitic imidazolate framework 8 (ZIF-8) crystals were grown in micro columnar TiO2 films through simple alternate and successive immersions of the TiO2 films into solutions containing the MOFs precursors. The growth process of the MOF crystals in the interstitial spaces between the TiO2 columns was investigated by varying the metal-to-ligand ratio (1:2, 1:4, and 1:8) and by employing modulating agents such as triethylamine. It was found that the optimal deposition of ZIF-8 occurred when using a higher excess of ligand and the addition of triethylamine after a controlled number of immersion cycles. These results were obtained by using glancing angle X-ray diffraction (GAXRD) and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) as characterization techniques. Additionally, a density functional theory (DFT) study as well as Fourier-transform infrared spectroscopy (FTIR) and GAXRD experiments were conducted to elucidate the nucleation process. It was concluded that the starting point is the formation of a covalent bond between the Zn cations and the TiO2 on the metal oxide surface after immersion of the film into a Zinc (II) nitrate solution, allowing for the formation of MOF nuclei once the film is subsequently immersed in the 2-methylimidazole solution. The results demonstrate the feasibility of in situ growth of MOF crystals onto metal oxide structures by a layer-by-layer strategy, offering a promising alternative to conventional methods.