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Polymeric mixed ionic–electronic conductors hold great potential for advancing high‐performance organic electronics due to their exceptional electrical conductivity achieved through ion–electron coupling. However, the widespread adoption of these conductors faces obstacles due to their reliance on environmentally harmful solvents during processing and the potential performance degradation under various conditions. In this study, a practical solution to these challenges is proposed by incorporating monomers with ionic liquid‐behaving pendant groups into conjugated polymers. The copolymerization of these charged monomers not only improves solubility in environmentally friendly solvents but also imparts long‐term stability against humidity, high temperatures, and mechanical deformation. The immobilized ion species foster highly selective interactions of these polymers with nitrogen dioxide, paving the way for the development of stretchable sensing devices capable of functioning at exceptionally high temperatures. [ABSTRACT FROM AUTHOR]

A NO2 sensor based on optically sintered 2D Ru oxide nanosheets applied to a flexible heating substrate composed of a colorless polyimide film with embedded Ag nanowires is described by Hee Jung Park, Il‐Doo Kim, and co‐workers in article number 1606026. A sensitivity of 1.124% at 20 ppm and a wearable wireless sensor is demonstrated. [ABSTRACT FROM AUTHOR]

To achieve the rational design of nanostructures for superior gas sensors, the ultrasmall nanoparticles (NPs) loaded on ternary metal oxide (TMO) hollow spheres (HS) were synthesized by using the polystyrene (PS) sphere template and bimetallic metal-organic framework (BM-MOFs) mold. The zinc and cobalt based zeolite imidazole frameworks (BM-ZIFs) encapsulating ultrasmall Pd NPs (2-3 nm) were assembled on PS spheres at room temperature. After calcination at 450 °C, these nanoscale Pd particles were effectively infiltrated on the surface of ZnO/ZnCo2O4 HSs. In addition, the heterojunctions of Pd-ZnO, Pd-ZnCo2O4, and ZnO-ZnCo2O4 were formed on each phase. The synthesized Pd-ZnO/ZnCo2O4 HSs exhibited extremely high selectivity toward acetone gas with notable sensitivity (S = 69% to 5 ppm at 250 °C). The results demonstrate that MOF driven ultrasmall catalyst loaded TMO HSs were highly effective platform for high performance chemical gas sensors. [ABSTRACT FROM AUTHOR]

Keywords: perspiration electric generator-based fibers; triboelectric generator-based fibers; wearable energy harvesting; woven-structured energy harvesters EN perspiration electric generator-based fibers triboelectric generator-based fibers wearable energy harvesting woven-structured energy harvesters 1 1 1 07/31/23 20230727 NES 230727 B Dual Energy Harvesting Fabrics b In article number 2300530, Ji-Soo Jang, Hyun-Cheol Song, and co-workers demonstrate a dual energy harvesting fabric that enables bio-physicochemical generation through the co-weaving of triboelectric generator- and perspiration electric generator-based fibers. Perspiration electric generator-based fibers, triboelectric generator-based fibers, wearable energy harvesting, woven-structured energy harvesters The fabric harvests energy not only from human movement but also from sweat to power wearable IoT devices and exhibits remarkable washing durability. [Extracted from the article]

Highlights of this work include the following; (i) Fabrication of defect-free and uniformly porous ZIF-8 membrane on conductive 2D active materials, (ii) the realization of the ultra-stable and selective surface reaction behavior with fast response by coupling conductive 2D active materials with breathable ZIF-8 passivation layer. B 2D Materials b In article number 2301002, Jihan Kim, Chong-Yun Kang, Ji-Soo Jang, and co-workers describe "Sandwich-like" porous MOFs/2D conductive heterostructures for realizing ultra-stable and selective surface reactivity of conductive 2D materials as proven by chemical sensing case study and multiscale simulations. Moreover, a further developed model of the MOFs/2D conductive heterostructures system will actively contribute to overcoming the world-wide problem of unstable 2D material characteristics. [Extracted from the article]

Functionalization of catalytic nanoparticles (NPs) on semiconductor metal oxide (SMO) sensing layer is an indispensable process to obtain improved sensitivity and selectivity for high performance chemical sensors. It is a critical challenge to achieve homogeneous distribution of nanoscale catalysts on SMO in consideration that gas sensing characteristics of SMO-based sensing layer are significantly influenced by the size and distribution of catalysts. Here, we propose a highly effective functionalization method to achieve well-distributed catalytic NPs onto one dimensional (1D) SMO nanofibers (NFs) using protein cage templates: apoferrtin. By simply replacing precursor in the apoferritin assisted method, not only precious catalyst such as Pt but also non-precious catalysts such as La and Cu were successfully synthesized in nanoscale ( i.e. , 3–5 nm). Furthermore, the apoferritin-encapsulated catalysts exhibited high dispersion property due to repulsive force between protein shells. For this reason, catalytic NPs were homogeneously decorated on ZnO NFs after electrospinning followed by calcination. Catalytic Pt NPs and Cu NPs functionalized ZnO NFs exhibited approximately 6.38-fold (R air /R gas = 13.07) and 2.95-fold (R air /R gas = 6.04) improved acetone response compared with the response (R air /R gas = 2.05) of pristine ZnO NFs. In the case of La NPs functionalized ZnO NFs, 9.31-fold improved nitrogen monoxide response (R air /R gas = 10.06) was achieved compared with the response of pristine ZnO NFs. The four catalyst-ZnO composite NFs successfully distinguished simulated breath components such as acetone, toluene, nitrogen monoxide, carbon monoxide, and ammonia with well-classified patterns by principal component analysis (PCA). This work demonstrated a robustness of synthetic and functionalization method using bio-inspired protein templates combined with electrospinning technique and a promising potential of using non-precious catalysts to establish diverse sensing material libraries that can be applicable to breath pattern recognition for diagnosis of diseases. [ABSTRACT FROM AUTHOR]

The PEH design methodology to implement the ART function is provided along with its real-world validation under low-frequency (<100 Hz) complex vibrations in which the acceleration and frequency change simultaneously. To maximize the harvesting power, the resonance frequency of the PEH should match the dominant frequency of the ambient vibrations. B Piezoelectric Energy Harvester b A piezoelectric energy harvester (PEH) that converts unused ambient vibration energy into useful electricity can alleviate issues related to the battery maintenance and power line installation of IoT sensors. [Extracted from the article]

[Display omitted] • A nonlinear broadband piezoelectric energy harvester with a coupled beam array is proposed, which combines multi-resonance, coupling effect, and structural nonlinearity to broaden operational bandwidth and improve energy harvesting efficiency. • The coupling effect is numerically analyzed between two beams. • The energy harvesting performance of the harvester is compared with a non-coupled multi-resonance harvester constructed by individually separated beams, to show its superiority. • An energy harvesting demonstration on a sensor claims that the harvester can generate useful power for IoT devices. • Vehicle engine test verifies that the harvester can be applied in unstable conditions where varying frequencies exist. A conventional energy harvester usually has narrow operational bandwidth, which makes it difficult to harvest energy with varying frequencies in the actual field. Herein, a nonlinear piezoelectric energy harvester with a coupled beam array is designed to broaden bandwidth and improve energy harvesting performance. The proposed harvester consists of a base, two elastic supports, and four piezoelectric beams with different natural frequencies. Due to the coupling effect caused by the two elastic supports, the four piezoelectric beams have large output voltages not only at their own natural frequencies, but also at the natural frequencies of other beams. Meanwhile, the two elastic supports enable the four piezoelectric beams to become nonlinear beams, which also contributes to operational bandwidth broadening. Next, the equivalent mass-spring-damping model and governing equations of the harvester are obtained, based on the lumped-parameter method. A strong coupling is found to occur when the equivalent stiffness of the elastic support is small. Subsequently, a fabricated prototype and an experiment platform are utilized to measure the energy harvesting performance of the harvester. Under 1 g up-sweep excitation, the average output power of the harvester from 40 Hz to 80 Hz is 144.2 % higher and the bandwidth is 93.3 % wider than those of the non-coupled multi-resonance harvester, which houses four beams separately. Finally, actual applicability of the proposed energy harvester is evaluated by operating a Bluetooth location tracking Internet of Things (IoT) device without a battery. Besides, the fabricated prototype is applied to the vehicle engine where the frequencies of vibration sources change rapidly with time and velocity. The field test argues that the harvester can be used in unstable or varying conditions, where a typical vibration energy harvester may not work efficiently, due to its limited operational bandwidth. [ABSTRACT FROM AUTHOR]

In this work, highly porous WO 3 nanotubes (NTs) were synthesized by facile layer-by-layer (LbL) self-assembly on polymeric nanofiber (NF) templates followed by calcination. Polymeric NFs using poly(methyl methacrylate) (PMMA) were prepared by electrospinning as sacrificial templates. Then, ionic polymers were coated on PMMA to modify the surface charge of PMMA NFs. Catalyst-loaded WO 3 NTs were synthesized by self-assembly of tungsten precursor and catalytic precursor on the surface of the polymeric PMMA NFs followed by calcination at 500 °C for 1 h. Gas sensing performances were evaluated in highly humid atmosphere (90% RH) using pristine WO 3 NTs, Pt-loaded WO 3 NTs (Pt-WO 3 NTs), and Pd-loaded WO 3 NTs (Pd-WO 3 NTs). Pristine WO 3 NTs exhibited a high NO response ( R gas / R air = 63.59 at 5 ppm) at 350 °C and cross-selectivity toward toluene ( R air / R gas = 1.05 at 5 ppm). On the other hand, Pt-WO 3 NTs and Pd-WO 3 NTs exhibited a high toluene response ( R air / R gas = 2.24 for the Pt-WO 3 NTs and R air / R gas = 2.35 for the Pd-WO 3 NTs at 5 ppm) at 400 °C and a negligible NO response ( R gas / R air = 1.25 for the Pt-WO 3 NTs and R gas / R air = 1.04 for the Pd-WO 3 NTs at 5 ppm) at 400 °C. These results demonstrated that LbL synthesis is a highly promising method for producing hollow semiconductor metal oxide NTs functionalized with various catalysts, which leads to potential application in exhaled breath analysis for asthma and lung cancer diagnosis. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple but powerful solution to overcome the chronic bottleneck of the nanocatalyst delivery on oxide support: the carbothermal shock driven nanocatalyst formation on carbon nanofibers (CNFs) with small sizes and fine distribution can be delivered to oxide structures of choice while retaining high uniformity. • Fabrication of catalyst delivered porous oxide structures: the asymmetric sputtering of oxide on CNFs can induce the formation of openly porous hemi-tubular structures with tunable porosity and thickness. A simple subsequent calcination results in the transfer of catalysts from the CNF template to the porous oxide structures. • Superior hydrogen sulfide sensing properties: Uniform distribution of Pt nanoparticles on SnO 2 hemitubes showed superior H 2 S sensing performances (Response Rair/Rgas > 1500 at 5 ppm H 2 S) compared to state-of-the-art H 2 S sensors. To achieve powerful gas sensors oxide semiconductor chemiresistors, the uniform functionalization of nanocatalysts on the desired metal oxides is considered as a key strategy. However, still, it is challenging to achieve the nanocatalysts decoration on desired oxides without deterioration of target materials. In this study, thermal-shock (rapid joule-heating method) was applied to uniformly decorate Pt nanoparticles (NPs) on the surface of carbon nanofibers (CNFs) to achieve the uniform distribution of Pt NPs on one-dimensional structures. And then, SnO 2 was physically deposited on the Pt NPs loaded CNFs and continuous heat-treatment was conducted to transfer the Pt NPs to desired SnO 2 porous hemitubes. Thanks to the well-distributed Pt NPs on porous SnO 2 hollow structures, the Pt laoded SnO 2 hemitubes showed an exceptional sensitivity (R air /R gas = 1500 at 5 ppm) in H 2 S. Also, it showed high selectivity for H 2 S and high stability even under continuous gas exposure, confirming its potential as an effective H 2 S sensor. [ABSTRACT FROM AUTHOR]

Background: Sentinel lymph node biopsy (SLNB) is recommended for patients with ductal carcinoma in situ (DCIS) undergoing mastectomy, given the concerns regarding upstaging and technical difficulties of post-mastectomy SLNB. However, this may lead to potential overtreatment, considering favorable prognosis and de-escalation trends in DCIS. Data regarding upstaging and axillary lymph node metastasis among these patients remain limited., Methods: We retrospectively reviewed patients with DCIS who underwent mastectomy with SLNB or axillary lymph node dissection at Gangnam Severance Hospital between January 2010 and December 2021. To explore the feasibility of omitting SLNB, we assessed the rates of DCIS upgraded to invasive carcinoma and axillary lymph node metastasis. Binary Cox regression analysis was performed to identify clinicopathologic factors associated with upstaging and axillary lymph node metastasis., Results: Among 385 patients, 164 (42.6%) experienced an invasive carcinoma upgrade: microinvasion, pT1, and pT2 were confirmed in 53 (13.8%), 97 (25.2%), and 14 (3.6%) patients, respectively. Seventeen (4.4%) patients had axillary lymph node metastasis. Multivariable analysis identified age ≤ 50 years (adjusted odds ratio [OR], 12.73; 95% confidence interval [CI], 1.18-137.51; p = 0.036) and suspicious axillary lymph nodes on radiologic evaluation (adjusted OR, 9.31; 95% CI, 2.06-41.99; p = 0.004) as independent factors associated with axillary lymph node metastasis. Among patients aged > 50 years and/or no suspicious axillary lymph nodes, only 1.7-2.3%) experienced axillary lymph node metastasis., Conclusions: Although underestimation of the invasive component was relatively high among patients with DCIS undergoing mastectomy, axillary lymph node metastasis was rare. Our findings suggest that omitting SLNB may be feasible for patients over 50 and/or without suspicious axillary lymph nodes on radiologic evaluation., (© 2024. The Author(s).)

Respiratory masks are the primary and most effective means of protecting individuals from airborne hazards such as droplets and particulate matter during public engagements. However, conventional electrostatically charged melt-blown microfiber masks typically require thick and dense membranes to achieve high filtration efficiency, which in turn cause a significant pressure drop and reduce breathability. In this study, we have developed a multielectrospinning system to address this issue by manipulating the pore structure of nanofiber networks, including the use of uniaxially aligned nanofibers created via an electric-field-guided electrospinning apparatus. In contrast to the common randomly collected microfiber membranes, partially aligned dual-nanofiber membranes, which are fabricated via electrospinning of a random 150 nm nanofiber base layer and a uniaxially aligned 450 nm nanofiber spacer layer on a roll-to-roll collector, offer an efficient way to modulate nanofiber membrane pore structures. Notably, the dual-nanofiber configuration with submicron pore structure exhibits increased fiber density and decreased volume density, resulting in an enhanced filtration efficiency of over 97% and a 50% reduction in pressure drop. This leads to the highest quality factor of 0.0781. Moreover, the submicron pore structure within the nanofiber networks introduces an additional sieving filtration mechanism, ensuring superior filtration efficiency under highly humid conditions and even after washing with a 70% ethanol solution. The nanofiber mask provides a sustainable solution for safeguarding the human respiratory system, as it effectively filters and inactivates human coronaviruses while utilizing 130 times fewer polymeric materials than melt-blown filters. This reusability of our filters and their minimum usage of polymeric materials would significantly reduce plastic waste for a sustainable global society.

2D transition metal dichalcogenides (TMDs) have significant research interests in various novel applications due to their intriguing physicochemical properties. Notably, one of the 2D TMDs, SnS 2 , has superior chemiresistive sensing properties, including a planar crystal structure, a large surface-to-volume ratio, and a low electronic noise. However, the long-term stability of SnS 2 in humid conditions remains a critical shortcoming towards a significant degradation of sensitivity. Herein, it is demonstrated that the subsequent self-assembly of zeolite imidazolate framework (ZIF-8) can be achieved in situ growing on SnS 2 nanoflakes as the homogeneous porous materials. ZIF-8 layer on SnS 2 allows the selective diffusion of target gas species, while effectively preventing the SnS 2 from severe oxidative degradation. Molecular modeling such as molecular dynamic simulation and DFT calculation, further supports the mechanism of sensing stability and selectivity. From the results, the in situ grown ZIF-8 porous membrane on 2D materials corroborates the generalizable strategy for durable and reliable high-performance electronic applications of 2D materials., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Background: It is unclear whether upfront surgery or neoadjuvant chemotherapy is appropriate for first treatment in hormone receptor (HR)-positive human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients with 1-2 suspicious axillary lymph node (ALN) metastases on preoperative breast magnetic resonance imaging (MRI)., Method: We identified 282 patients with HR+HER2- breast cancer and 1-2 suspicious ALN metastases on baseline breast MRI (147 received upfront surgery; 135 received neoadjuvant chemotherapy). We evaluated the predictive clinicopathological factors for pN2-3 in the adjuvant setting and axillary pathologic complete response (pCR) in the neoadjuvant setting., Results: Lymphovascular invasion (LVI)-positive and clinical tumors >3 cm were significantly associated with pN2-3 in patients who received upfront surgery. The pN2-3 rate was 9.3% in patients with a clinical tumor ≤ 3 cm and LVI-negative versus 34.7% in the others (p < 0.001). The pN2-3 rate in patients with a clinical tumor ≤ 3 cm and LVI-negative and in the others were 9.3% versus 34.7% in all patients (p < 0.001), 10.7% versus 40.0% (p = 0.033) in patients aged < 50 years, and 8.5% versus 31.0% in patients aged ≥ 50 years (p < 0.001), respectively. In the neoadjuvant setting, patients with tumor-infiltrating lymphocytes (TILs) ≥ 20% had a higher axillary pCR than those with TILs < 20% (46.7% vs. 15.3%, p < 0.001). A similar significant finding was also observed in patients < 50 years., Conclusions: Upfront surgery may be preferable for patients aged ≥ 50 years with a clinical tumor < 3 cm and LVI-negative, while neoadjuvant chemotherapy may be preferable for those aged < 50 years with TILs ≥ 20%., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lee, Ahn, Ji, Kook, Jang, Baek, Jeong and Bae.)

Background Nipple-sparing mastectomy (NSM) is usually contraindicated in patients with nonmass enhancement (NME) extension to the nipple at breast MRI. However, little is known about the feasibility of NSM when NME extension to the nipple resolves after neoadjuvant chemotherapy (NAC). Purpose To evaluate whether NSM is an appropriate surgical procedure for patients in whom NME extension to the nipple resolves after NAC. Materials and Methods This retrospective study included 383 women with NME at baseline MRI who underwent NAC followed by mastectomy between January 2007 and March 2022 at a single institution. NME extension to the nipple was assessed using breast MRI before NAC (hereafter, pre-NAC) and after NAC (hereafter, post-NAC). In 326 women who underwent mastectomy with removal of the nipple-areolar complex, the rate of pathologic analysis-confirmed tumor invasion of the nipple compared with NME extension to the nipple at post-NAC breast MRI was evaluated. Tumor involvement of the nipple was also assessed in those with complete pathologic response at posttreatment MRI. Furthermore, the outcomes in 57 women undergoing NSM were investigated, particularly in patients with NME extension to the nipple at initial diagnosis. Results Of the 326 women who underwent mastectomy with removal of the nipple-areolar complex (mean age, 49 years ± 9.4 [SD]), 217 patients (67%) showed NME extension to the nipple on pre-NAC MRI scans. Among the 153 women (70%) in whom the NME extension to the nipple resolved after NAC, the rate of pathologic analysis-confirmed tumor invasion of the nipple was 2.6% (four of 153 women; 95% CI: 0, 6.5). No pathologic analysis-confirmed tumor invasion of the nipple was detected in 31 women with complete response at MRI. Of the 57 women who underwent NSM, 12 (21%) with resolution of NME extension to the nipple after NAC had no relapse during the median follow-up of 31 months (range, 11-80 months). Conclusion Pathologic analysis-confirmed tumor invasion of the nipple was rare in women with resolution of nonmass enhancement extension to the nipple after neoadjuvant chemotherapy (NAC). Therefore, nipple-sparing mastectomy could be feasible in this population, especially in those with complete MRI response to NAC. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Lee in this issue.

Boosting dielectric permittivity representing electrical polarizability of dielectric materials has been considered a keystone for achieving scientific breakthroughs as well as technological advances in various multifunctional devices. Here, we demonstrate sizable enhancements of low-frequency dielectric responses in oxygen-deficient oxide ceramics through specific treatments under humid environments. Ultrahigh dielectric permittivity (~5.2 × 10 6 at 1 Hz) is achieved by hydrogenation, when Ni-substituted BaTiO 3 ceramics are exposed to high humidity. Intriguingly, thermal annealing can restore the dielectric on-state (exhibiting huge polarizability in the treated ceramics) to the initial dielectric off-state (displaying low polarizability of ~10 3 in the pristine ceramics after sintering). The conversion between these two dielectric states via the ambient environment-mediated treatments and the successive application of external stimuli allows us to realize reversible control of dielectric relaxation characteristics in oxide ceramics. Conceptually, our findings are of practical interest for applications to highly efficient dielectric-based humidity sensors.

Hydroelectric nanogenerators have been previously proposed to recycle various water resources and polluted water. However, as conventional hydroelectric nanogenerators only utilize water resources, they cannot provide a fundamental solution for water recycling. In this study, a water purification membrane is proposed that can simultaneously generate electricity during the purification process (electricity generation and purification membrane (EPM)) for water recycling. As polluted water passes through the EPM, the water is purified in the perpendicular direction, while electricity is simultaneously produced in the horizontal direction by the movement of ions. Notably, the EPM exhibits high energy generation performance (maximum power 16.44 µW and energy 15.16 mJ) by the streaming effect of water-streaming carbon nanotubes (CNTs). Moreover, by using a poly(acrylic acid)/carboxymethyl cellulose (PAA/CMC) binder to EPM, the energy-generation performance and long-term stability are substantially improved and outstanding mechanical stability is provided, regardless of the acidity of the water source (pH 1-10). More importantly, the EPM exhibits the water purification characteristics of >90% rejection of sub-10 nm pollutants and potentiality of ångstrom level cation rejection, with simultaneous and continuous energy generation. Overall, this study proposes an efficient EPM model, which can be potentially used as a next-generation renewable energy generation approach, thus laying the foundation for effective utilization of polluted water resources., (© 2022 Wiley-VCH GmbH.)

We report the epitaxial growth of (2̅01)-oriented β-Ga 2 O 3 thin films on a (001) Si substrate using the pulsed laser deposition technique employing epitaxial yttria-stabilized zirconia (YSZ) buffer layers. Epitaxial β-Ga 2 O 3 thin films possess a biaxial compressive strain on YSZ single-crystal substrates while they exhibit a biaxial tensile strain on YSZ-buffered Si substrates. Post-annealing improves the crystalline quality of β-Ga 2 O 3 thin films. High-resolution X-ray diffraction analyses reveal that the epitaxial (2̅01) β-Ga 2 O 3 thin films on Si have eight in-plane domain variants to accommodate the large difference in the crystal structure between monoclinic β-Ga 2 O 3 and cubic YSZ. The results provide a pathway to integrate epitaxial β-Ga 2 O 3 thin films on a Si gold standard substrate, which will expand the application scope beyond high-power electronics., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

The process of exsolution for the synthesis of strongly anchored metal nanoparticles (NPs) on host oxide lattices has been proposed as a promising strategy for designing robust catalyst-support composite systems. However, because conventional exsolution processes occur in harsh reducing environments at high temperatures for long periods of time, the choice of support materials and dopant metals are limited to those with inherently high thermal and chemical stability. Herein, we report the exsolution of a series of noble metal catalysts (Pt, Rh, and Ir) from metal oxide nanofibers (WO 3 NFs) supports in an entirely ambient environment induced by intense pulsed light (IPL)-derived momentary photothermal treatment (>1000 °C). Since the exsolution process spans an extremely short period of time (<20 ms), unwanted structural artifacts such as decreased surface area and phase transition of the support materials are effectively suppressed. At the same time, exsolved NPs (<5 nm) with uniform size distributions could successfully be formed. To prove the practical utility of exsolved catalytic NPs functionalized on WO 3 NFs, the chemiresistive gas sensing characteristics of exsolved Pt-decorated WO 3 NFs were analyzed, exhibiting high durability (>200 cyclic exposures), enhanced response ( R air / R gas > 800 @ 1 ppm/350 °C), and selectivity toward H 2 S target gas. Altogether, we successfully demonstrated that ultrafast exsolution within a few milliseconds could be induced in ambient conditions using the IPL-derived momentary photothermal treatment and contributed to expanding the practical viability of the exsolution-based synthetic approaches for the production of highly stable catalyst systems.

Though highly promising as powerful gas sensors, oxide semiconductor chemiresistors have low surface reactivity, which limits their selectivity, sensitivity, and reaction kinetics, particularly at room temperature (RT) operation. It is proposed that a hybrid design involving the nanostructuring of oxides and passivation with selective gas filtration layers can potentially overcome the issues with surface activity. Herein, unique bi-stacked heterogeneous layers are introduced; that is, nanostructured oxides covered by conformal nanoporous gas filters, on ultrahigh-density nanofiber (NF) yarns via sputter deposition with indium tin oxide (ITO) and subsequent self-assembly of zeolitic imidazolate framework (ZIF-8) nanocrystals. The NF yarn composed of ZIF-8-coated ITO films can offer heightened surface activity at RT because of high porosity, large surface area, and effective screening of interfering gases. As a case study, the hybrid sensor demonstrated remarkable sensing performances characterized by high NO selectivity, fast response/recovery kinetics (>60-fold improvement), and large responses (12.8-fold improvement @ 1 ppm) in comparison with pristine yarn@ITO, especially under highly humid conditions. Molecular modeling reveals an increased penetration ratio of NO over O 2 to the ITO surface, indicating that NO oxidation is reliably prevented and that the secondary adsorption sites provided by the ZIF-8 facilitate the adsorption/desorption of NO, both to and from ITO., (© 2022 Wiley-VCH GmbH.)

Practical sensing applications such as real-time safety alerts and clinical diagnoses require sensor devices to differentiate between various target molecules with high sensitivity and selectivity, yet conventional devices such as oxide-based chemo-resistive sensors and metal-based surface-enhanced Raman spectroscopy (SERS) sensors usually do not satisfy such requirements. Here, a label-free, chemo-resistive/SERS multimodal sensor based on a systematically assembled 3D cross-point multifunctional nanoarchitecture (3D-CMA), which has unusually strong enhancements in both "chemo-resistive" and "SERS" sensing characteristics is introduced. 3D-CMA combines several sensing mechanisms and sensing elements via 3D integration of semiconducting SnO 2 nanowire frameworks and dual-functioning Au metallic nanoparticles. It is shown that the multimodal sensor can successfully estimate mixed-gas compositions selectively and quantitatively at the sub-100 ppm level, even for mixtures of gaseous aromatic compounds (nitrobenzene and toluene) with very similar molecular structures. This is enabled by combined chemo-resistive and SERS multimodal sensing providing complementary information., (© 2021 Wiley-VCH GmbH.)

Continuous monitoring of hydrogen sulfide (H 2 S) in human breath for early stage diagnosis of halitosis is of great significance for prevention of dental diseases. However, fabrication of a highly selective and sensitive H 2 S gas sensor material still remains a challenge, and direct analysis of real breath samples has not been properly attempted, to the best of our knowledge. To address the issue, herein, we introduce facile cofunctionalization of WO 3 nanofibers with alkaline metal (Na) and noble metal (Pt) catalysts via the simple addition of sodium chloride (NaCl) and Pt nanoparticles (NPs), followed by electrospinning process. The Na-doping and Pt NPs decoration in WO 3 grains induces the partial evolution of the Na 2 W 4 O 13 phase, causing the buildup of Pt/Na 2 W 4 O 13 /WO 3 multi-interface heterojunctions that selectively interacts with sulfur-containing species. As a result, we achieved the highest-ranked sensing performances, that is, response ( R air / R gas ) = 780 @ 1 ppm and selectivity ( R H2S / R EtOH ) = 277 against 1 ppm ethanol, among the chemiresistor-based H 2 S sensors, owing to the synergistic chemical and electronic sensitization effects of the Pt NP/Na compound cocatalysts. The as-prepared sensing layer was proven to be practically effective for direct, and quantitative halitosis analysis based on the correlation (accuracy = 86.3%) between the H 2 S concentration measured using the direct breath signals obtained by our test device (80 cases) and gas chromatography. This study offers possibilities for direct, highly reliable and rapid detection of H 2 S in real human breath without the need of any collection or filtering equipment.

Conductive metal-organic frameworks (cMOFs) are emerging materials for various applications due to their high surface area, high porosity, and electrical conductivity. However, it is still challenging to develop cMOFs having high surface reactivity and durability. Here, highly active and stable cMOF are presented via the confinement of bimetallic nanoparticles (BNPs) in the pores of a 2D cMOF, where the confinement is guided by dipolar-interaction-induced site-specific nucleation. Heterogeneous metal precursors are bound to the pores of 2D cMOFs by dipolar interactions, and the subsequent reduction produces ultrasmall (≈1.54 nm) and well-dispersed PtRu NPs confined in the pores of the cMOF. PtRu-NP-decorated cMOFs exhibit significantly enhanced chemiresistive NO 2 sensing performances, owing to the bimetallic synergies of PtRu NPs and the high surface area and porosity of cMOF. The approach paves the way for the synthesis of highly active and conductive porous materials via bimetallic and/or multimetallic NP loading., (© 2021 Wiley-VCH GmbH.)

The development of highly efficient catalysts in the cathodes of rechargeable Li-O 2 batteries is a considerable challenge. Polyelemental catalysts consisting of two or more kinds of hybridized catalysts are particularly interesting because the combination of the electrochemical properties of each catalyst component can significantly facilitate oxygen evolution and oxygen reduction reactions. Despite the recent advances that have been made in this field, the number of elements in the catalysts has been largely limited to two metals. In this study, we demonstrate the electrochemical behavior of Li-O 2 batteries containing a wide range of catalytic element combinations. Fourteen different combinations with single, binary, ternary, and quaternary combinations of Pt, Pd, Au, and Ru were prepared on carbon nanofibers (CNFs) via a joule heating route. Importantly, the Li-O 2 battery performance could be significantly improved when using a polyelemental catalyst with four elements. The cathode containing quaternary nanoparticles (Pt-Pd-Au-Ru) exhibited a reduced overpotential (0.45 V) and a high discharge capacity based on total cathode weight at 9130 mAh g -1 , which was ∼3 times higher than that of the pristine CNF electrode. This superior electrochemical performance is be attributed to an increased catalytic activity associated with an enhanced O 2 adsorbability by the quaternary nanoparticles.

The colorimetric gas sensor offers an opportunity for the simple and rapid detection of toxic gaseous substances based on visually discernible changes in the color of the sensing material. In particular, the accurate detection of trace amounts of certain biomarkers in a patient's breath provides substantial clues regarding specific diseases, for example, hydrogen sulfide (H 2 S) for halitosis and ammonia (NH 3 ) for kidney disorder. However, conventional colorimetric sensors often lack the sensitivity, selectivity, detection limit, and mass-productivity, impeding their commercialization. Herein, we report an inexpensive route for the meter-scale synthesis of a colorimetric sensor based on a composite nanofiber yarn that is chemically functionalized with an ionic liquid as an effective H 2 S adsorbent and lead acetate as a colorimetric dye. As an eye-readable and weavable sensing platform, the single-strand yarn exhibits enhanced sensitivity supported by its high surface area and well-developed porosity to detect the breath biomarker (1 ppm of H 2 S). Alternatively, the yarn loaded with lead iodide dyes could reversibly detect NH 3 gas molecules in the ppm-level, demonstrating the facile extensibility. Finally, we demonstrated that the freestanding yarns could be sewn into patterned textiles for the fabrication of a wearable toxic gas alarm system with a visual output.

Catalysis with single-atom catalysts (SACs) exhibits outstanding reactivity and selectivity. However, fabrication of supports for the single atoms with structural versatility remains a challenge to be overcome, for further steps toward catalytic activity augmentation. Here, we demonstrate an effective synthetic approach for a Pt SAC stabilized on a controllable one-dimensional (1D) metal oxide nano-heterostructure support, by trapping the single atoms at heterojunctions of a carbon nitride/SnO 2 heterostructure. With the ultrahigh specific surface area (54.29 m 2 g -1 ) of the nanostructure, we obtained maximized catalytic active sites, as well as further catalytic enhancement achieved with the heterojunction between carbon nitride and SnO 2 . X-ray absorption fine structure analysis and HAADF-STEM analysis reveal a homogeneous atomic dispersion of Pt species between carbon nitride and SnO 2 nanograins. This Pt SAC system with the 1D nano-heterostructure support exhibits high sensitivity and selectivity toward detection of formaldehyde gas among state-of-the-art gas sensors. Further ex situ TEM analysis confirms excellent thermal stability and sinter resistance of the heterojunction-immobilized Pt single atoms.

For rapid hydrogen gas (H 2 ) sensing, we propose the facile synthesis of the hollow structure of Pt-decorated molybdenum disulfide (h-MoS 2 /Pt) using ultrathin (mono- or few-layer) two-dimensional nanosheets. The controlled amphiphilic nature of MoS 2 surface produces ultrathin MoS 2 NS-covered polystyrene particles via one-step Pickering emulsification. The incorporation of Pt nanoparticles (NPs) on the MoS 2 , followed by pyrolysis, generates the highly porous h-MoS 2 /Pt. This hollow hybrid structure produces sufficiently permeable pathways for H 2 and maximizes the active sites of MoS 2 , while the Pt NPs on the hollow MoS 2 induce catalytic H 2 spillover during H 2 sensing. The h-MoS 2 /Pt-based chemiresistors show sensitive H 2 sensing performances with fast sensing speed (response, 8.1 s for 1% of H 2 and 2.7 s for 4%; and recovery, 16.0 s for both 1% and 4% H 2 at room temperature in the air). These results mark the highest H 2 sensing speed among 2D material-based H 2 sensors operated at room temperature in air. Our fabrication method of h-MoS 2 /Pt structure through Pickering emulsion provides a versatile platform applicable to various 2D material-based hollow structures and facilitates their use in other applications involving surface reactions.

Multi-heterogeneous oxide sensing layers, i.e., NiO/Fe2O3 catalyst loaded SnO2 fiber-in-tube nanostructures (NiO/Fe2O3-FITs), were rationally synthesized from an electrospinning solution containing a bio-inspired chitosan-bimetal complex template. The NiO/Fe2O3-FITs showed remarkably enhanced sensing properties and superior cross-sensitivity toward sub-ppm levels of formaldehyde.

In this work, we introduce a chitosan-Pt complex (CS-Pt) as an effective template for catalytic Pt sensitization and creation of abundant mesopores in SnO2 nanofibers (NFs). The Pt particles encapsulated by the CS exhibit ultrasmall size (∼2.6 nm) and high dispersion characteristics due to repulsion between CS molecules. By combining CS-Pt with electrospinning, mesoporous SnO2 NFs uniformly functionalized with the Pt catalyst (CS-Pt@SnO2 NFs) are synthesized. Particularly, numerous mesopores with diameters of ∼20 nm form through the decomposition of CS, while a small SnO2 grain size (14.32 nm) is achieved by the pinning effect of CS. It is observed that CS-Pt@SnO2 NFs exhibit outstanding response (Rair/Rgas = 141.92 at 5 ppm), excellent selectivity, stability, and fast response (12 s)/recovery (44 s) speed toward 1 ppm of acetone at 350 °C and high humidity (90% RH). In addition, by applying an exponential fitting tool to experimental response values toward 0.1-5 ppm of acetone, it is estimated that CS-Pt@SnO2 NFs can detect 5 ppb of acetone with a notable response (Rair/Rgas = 2.9). Furthermore, the sensor array based on CS-Pt@SnO2 NFs, CS-driven SnO2 NFs, polyol-Pt loaded SnO2 NFs, and dense SnO2 NFs obviously classifies simulated diabetic breath and healthy human breath by using a pattern recognition tool. These results clearly demonstrate that mesoporous SnO2 NFs, particularly functionalized with CS-Pt templated nanocatalysts, open up a new class of sensing layers offering high sensitivity and selectivity.

Herein, we incorporated dual biotemplates, i.e., cellulose nanocrystals (CNC) and apoferritin, into electrospinning solution to achieve three distinct benefits, i.e., (i) facile synthesis of a WO 3 nanotube by utilizing the self-agglomerating nature of CNC in the core of as-spun nanofibers, (ii) effective sensitization by partial phase transition from WO 3 to Na 2 W 4 O 13 induced by interaction between sodium-doped CNC and WO 3 during calcination, and (iii) uniform functionalization with monodispersive apoferritin-derived Pt catalytic nanoparticles (2.22 ± 0.42 nm). Interestingly, the sensitization effect of Na 2 W 4 O 13 on WO 3 resulted in highly selective H 2 S sensing characteristics against seven different interfering molecules. Furthermore, synergistic effects with a bioinspired Pt catalyst induced a remarkably enhanced H 2 S response ( R air / R gas = 203.5), unparalleled selectivity ( R air / R gas < 1.3 for the interfering molecules), and rapid response (<10 s)/recovery (<30 s) time at 1 ppm of H 2 S under 95% relative humidity level. This work paves the way for a new class of cosensitization routes to overcome critical shortcomings of SMO-based chemical sensors, thus providing a potential platform for diagnosis of halitosis.

Bimodally meso- (2-50 nm) and macroporous (>50 nm) WO 3 microbelts (MBs) functionalized with sub-3 nm Pt catalysts were fabricated via the electrospinning technique followed by subsequent calcination. Importantly, apoferritin (Apo), tea saponin and polystyrene colloid spheres (750 nm) dispersed in an electrospinning solution acted as forming agents for producing meso- and macropores on WO 3 MBs during calcination. Particularly, mesopores provide not only numerous reaction sites for effective chemical reactions, but also facilitate gas diffusion into the interior of the WO 3 MBs, dominated by Knudsen diffusion. The macropores further accelerate gas permeability in the interior and on the exterior of the WO 3 MBs. In addition, Pt nanoparticles with mean diameters of 2.27 nm were synthesized by using biological protein cages, such as Apo, to further enhance the gas sensing performance. Bimodally porous WO 3 MBs functionalized by Pt catalysts showed remarkably high hydrogen sulfide (H 2 S) response ( R air / R gas = 61 @ 1 ppm) and superior selectivity to H 2 S against other interfering gases, such as acetone (CH 3 COCH 3 ), ethanol (C 2 H 5 OH), ammonia (NH 3 ), and carbon monoxide (CO). These results demonstrate a high potential for the feasibility of catalyst-loaded meso- and macroporous WO 3 MBs as new sensing platforms for the possibility of real-time diagnosis of halitosis.

Lithium-oxygen batteries have been considered as one of the most viable energy source options for electric vehicles due to their high energy density. However, they are still faced with technical challenges, such as low round-trip efficiency and short cycle life, which mainly originate from the cathode part of the battery. In this work, we designed a three-dimensional nanofibrous air electrode consisted of hierarchically structured carbon nanotube-bridged hollow Fe 2 O 3 nanoparticles (H-Fe 2 O 3 /CNT NFs). Composite nanofibers consisted of hollow Fe 2 O 3 NPs anchored by multiple CNTs offered enhanced catalytic sites (interconnected hollow Fe 2 O 3 NPs) and fast charge-transport highway (bridged CNTs) for facile formation and decomposition of Li 2 O 2 , leading to outstanding cell performance: (1) Swagelok cell exhibited highly reversible cycling characteristics for 250 cycles with a fixed capacity of 1000 mAh g -1 at a current density of 500 mA g -1 . (2) A module composed of two pouch-type cells stably powered an light-emitting diode lamp operated at 5.0 V.

PtO 2 nanocatalysts-loaded SnO 2 multichannel nanofibers (PtO 2 -SnO 2 MCNFs) were synthesized by single-spinneret electrospinning combined with apoferritin and two immiscible polymers, i.e., poly(vinylpyrrolidone) and polyacrylonitrile. The apoferritin, which can encapsulate nanoparticles within a small inner cavity (8 nm), was used as a catalyst loading template for an effective functionalization of the PtO 2 catalysts. Taking advantage of the multichannel structure with a high porosity, effective activation of catalysts on both interior and exterior site of MCNFs was realized. As a result, under high humidity condition (95% RH), PtO 2 -SnO 2 MCNFs exhibited a remarkably high acetone response (R air /R gas = 194.15) toward 5 ppm acetone gases, superior selectivity to acetone molecules among various interfering gas species, and excellent stability during 30 cycles of response and recovery toward 1 ppm acetone gases. In this work, we first demonstrate the high suitability of multichannel semiconducting metal oxides structure functionalized by apoferritin-encapsulated catalytic nanoparticles as highly sensitive and selective gas-sensing layer.

The oxygen, O 2 , in air interferes with the detection of H 2 by palladium (Pd)-based H 2 sensors, including Pd nanowires (NWs), depressing the sensitivity and retarding the response/recovery speed in air-relative to N 2 or Ar. Here, we describe the preparation of H 2 sensors in which a nanofiltration layer consisting of a Zn metal-organic framework (MOF) is assembled onto Pd NWs. Polyhedron particles of Zn-based zeolite imidazole framework (ZIF-8) were synthesized on lithographically patterned Pd NWs, leading to the creation of ZIF-8/Pd NW bilayered H 2 sensors. The ZIF-8 filter has many micropores (0.34 nm for gas diffusion) which allows for the predominant penetration of hydrogen molecules with a kinetic diameter of 0.289 nm, whereas relatively larger gas molecules including oxygen (0.345 nm) and nitrogen (0.364 nm) in air are effectively screened, resulting in superior hydrogen sensing properties. Very importantly, the Pd NWs filtered by ZIF-8 membrane (Pd NWs@ZIF-8) reduced the H 2 response amplitude slightly (ΔR/R 0 = 3.5% to 1% of H 2 versus 5.9% for Pd NWs) and showed 20-fold faster recovery (7 s to 1% of H 2 ) and response (10 s to 1% of H 2 ) speed compared to that of pristine Pd NWs (164 s for response and 229 s for recovery to 1% of H 2 ). These outstanding results, which are mainly attributed to the molecular sieving and acceleration effect of ZIF-8 covered on Pd NWs, rank highest in H 2 sensing speed among room-temperature Pd-based H 2 sensors.

The influence of hexamethylenetetraamine (HMTA) on the morphology of δ-MnO 2 and its properties for electrical energy storage are investigated-specifically for ultrathick δ-MnO 2 layers in the micron scale. Planar arrays of gold@δ-MnO 2 , core@shell nanowires, were prepared by electrodeposition with and without the HMTA and their electrochemical properties were evaluated. HMTA alters the MnO 2 in three ways: First, it creates a more open morphology for the MnO 2 coating, characterized by "petals" with a thickness of 6 to 9 nm, rather than much thinner δ-MnO 2 sheets seen in the absence of HMTA. Second, the electronic conductivity of the δ-MnO 2 is increased by an order of magnitude. Third, δ-MnO 2 prepared in HMTA shows a (001) interlayer spacing that is expanded by ≈30% possibly accelerating Li transport. The net effect of "HTMA doping" is to dramatically improve high rate performance, culminating in an increase in the specific capacity for the thickest MnO 2 shells examined here by a factor of 15 at 100 mV/s.

Background: When considering various risk factors such as age, comorbidities, and complications related to the surgical procedure itself, open surgery in degenerative spinal stenosis is likely to cause more complications. Here, we report the surgical procedure and preliminary clinical results of percutaneous endoscopic stenosis lumbar decompression (PESLD) technique using a uniportal-contralateral approach for bilateral decompression of degenerative spinal stenosis., Materials and Methods: Electronic medical records of 48 consecutive patients who were treated between January 2016 and August 2016 were reviewed retrospectively. All patient received PESLD through the uniportal-contralateral approach. We analyzed the outcomes using the visual analogue scale, Macnab criteria, Oswestry Disability Index, and complication rate., Results: There were 48 cases (15 men, 33 women). Mean age of patients was 62.44 ± 8.68 years. Mean symptom duration was 20.13 ± 16.87 months. Neurogenic intermittent claudication was 550 m on average. Follow-up period was 7.75 ± 2.28 months (range, 5-13 months). Visual analogue scale and Oswestry Disability Index decreased significantly (P < 0.001) and decreased by 1.073 and 5.795 odds ratio, respectively, in contralateral foraminotomy cases. Macnab outcome grade was good to excellent in 96% of patients. Dural tear occurred in 3 cases (6.25%), and 2 cases (4.17%) required transforaminal lumbar interbody fusion operation after this procedure., Conclusions: The preliminary result of this uniportal-contralateral PESLD technique is encouraging (96% demonstrated a good-to-excellent outcome), and the procedure is safe. However, we need long-term follow-up and a more detailed study for more accurate results of this technique., (Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.)

Metal-organic framework (MOF)-derived synergistic catalysts were easily functionalized on hollow SnO 2 nanotubes (NTs) via electrospinning and subsequent calcination. Nanoscale Pd NPs (∼2 nm) loaded Zn-based zeolite imidazole framework (Pd@ZIF-8, ∼80 nm) was used as a new catalyst-loading platform for the effective functionalization of a PdO@ZnO complex catalyst onto the thin wall of one-dimensional metal oxide NTs. The well-dispersed nanoscale PdO catalysts (3-4 nm) and multiheterojunctions (PdO/ZnO and ZnO/SnO 2 ) on hollow structures are essential for the development of high-performance gas sensors. As a result, the PdO@ZnO dual catalysts-loaded hollow SnO 2 NTs (PdO@ZnO-SnO 2 NTs) exhibited high acetone response (R air /R gas = 5.06 at 400 °C @ 1 ppm), superior acetone selectivity against other interfering gases, and fast response (20 s) and recovery (64 s) time under highly humid atmosphere (95% RH). In this work, the advantages of hollow SnO 2 NT structures with high surface area and open porosity were clearly demonstrated by the comparison to SnO 2 nanofibers (NFs). Moreover, the sensor arrays composed of SnO 2 NFs, SnO 2 NTs, PdO@ZnO-SnO 2 NFs, and PdO@ZnO-SnO 2 NTs successfully identified the patterns of the exhaled breath of normal people and simulated diabetics by using a principal component analysis.

To achieve the rational design of nanostructures for superior gas sensors, the ultrasmall nanoparticles (NPs) loaded on ternary metal oxide (TMO) hollow spheres (HS) were synthesized by using the polystyrene (PS) sphere template and bimetallic metal-organic framework (BM-MOFs) mold. The zinc and cobalt based zeolite imidazole frameworks (BM-ZIFs) encapsulating ultrasmall Pd NPs (2-3 nm) were assembled on PS spheres at room temperature. After calcination at 450 °C, these nanoscale Pd particles were effectively infiltrated on the surface of ZnO/ZnCo 2 O 4 HSs. In addition, the heterojunctions of Pd-ZnO, Pd-ZnCo 2 O 4 , and ZnO-ZnCo 2 O 4 were formed on each phase. The synthesized Pd-ZnO/ZnCo 2 O 4 HSs exhibited extremely high selectivity toward acetone gas with notable sensitivity (S = 69% to 5 ppm at 250 °C). The results demonstrate that MOF driven ultrasmall catalyst loaded TMO HSs were highly effective platform for high performance chemical gas sensors.

The increase of surface area and the functionalization of catalyst are crucial to development of high-performance semiconductor metal oxide (SMO) based chemiresistive gas sensors. Herein, nanoscale catalyst loaded Co 3 O 4 hollow nanocages (HNCs) by using metal-organic framework (MOF) templates have been developed as a new sensing platform. Nanoscale Pd nanoparticles (NPs) were easily loaded on the cavity of Co based zeolite imidazole framework (ZIF-67). The porous structure of ZIF-67 can restrict the size of Pd NPs (2-3 nm) and separate Pd NPs from each other. Subsequently, the calcination of Pd loaded ZIF-67 produced the catalytic PdO NPs functionalized Co 3 O 4 HNCs (PdO-Co 3 O 4 HNCs). The ultrasmall PdO NPs (3-4 nm) are well-distributed in the wall of Co 3 O 4 HNCs, the unique structure of which can provide high surface area and high catalytic activity. As a result, the PdO-Co 3 O 4 HNCs exhibited improved acetone sensing response (R gas /R air = 2.51-5 ppm) compared to PdO-Co 3 O 4 powders (R gas /R air = 1.98), Co 3 O 4 HNCs (R gas /R air = 1.96), and Co 3 O 4 powders (R gas /R air = 1.45). In addition, the PdO-Co 3 O 4 HNCs showed high acetone selectivity against other interfering gases. Moreover, the sensor array clearly distinguished simulated exhaled breath of diabetics from healthy people's breath. These results confirmed the novel synthesis of MOF templated nanoscale catalyst loaded SMO HNCs for high performance gas sensors.

Rational design of nanostructures and efficient catalyst functionalization methods are critical to the realization of highly sensitive gas sensors. In order to solve these issues, two types of strategies are reported, i.e., (i) synthesis of peapod-like hollow SnO 2 nanostructures (hollow 0D-1D SnO 2 ) by using fluid dynamics of liquid Sn metal and (ii) metal-protein chelate driven uniform catalyst functionalization. The hollow 0D-1D SnO 2 nanostructures have advantages in enhanced gas accessibility and higher surface areas. In addition to structural benefits, protein encapsulated catalytic nanoparticles result in the uniform catalyst functionalization on both hollow SnO 2 spheres and SnO 2 nanotubes due to their dynamic migration properties. The migration of catalysts with liquid Sn metal is induced by selective location of catalysts around Sn. On the basis of these structural and uniform functionalization of catalyst benefits, biomarker chemical sensors are developed, which deliver highly selective detection capability toward acetone and toluene, respectively. Pt or Pd loaded multidimensional SnO 2 nanostructures exhibit outstanding acetone (R air /R gas = 93.55 @ 350 °C, 5 ppm) and toluene (R air /R gas = 9.25 @ 350 °C, 5 ppm) sensing properties, respectively. These results demonstrate that unique nanostructuring and novel catalyst loading method enable sensors to selectively detect biomarkers for exhaled breath sensors., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)