Thin‐Wall Assembled SnO₂ Fibers Functionalized by Catalytic Pt Nanoparticles and their Superior Exhaled‐Breath‐Sensing Properties for the Diagnosis of Diabetes

Abstract

Hierarchical SnO 2 fi bers assembled from wrinkled thin tubes are synthesized by controlling the microphase separation between tin precursors and polymers, by varying fl ow rates during electrospinning and a subsequent heat treatment. The inner and outer SnO 2 tubes have a number of elongated open pores ranging from 10 nm to 500 nm in length along the fi ber direction, enabling fast transport of gas molecules to the entire thin-walled sensing layers. These features admit exhaled gases such as acetone and toluene, which are markers used for the diagnosis of diabetes and lung cancer. The open tubular structures facilitated the uniform coating of catalytic Pt nanoparticles onto the inner SnO 2 layers. Highly porous SnO 2 fi bers synthesized at a high fl ow rate show fi ve-fold higher acetone responses than densely packed SnO 2 fi bers synthesized at a low fl ow rate. Interestingly, thin-wall assembled SnO 2 fi bers functionalized by Pt particles exhibit a dramatically shortened gas response time compared to that of un-doped SnO 2 fi bers, even at low acetone concentrations. Moreover, Pt-decorated SnO 2 fi bers signifi cantly enhance toluene response. These results demonstrate the novel and practical feasibility of thin-wall assembled metal oxide based breath sensors for the accurate diagnosis of diabetes and potential detection of lung cancer.

Optical and magnetic properties of (Er, F) co-doped SnO$_{2}$ nanocrystals

“…Mean pore diameter increased from 2.62 nm (Er-doped SnO 2 ) to 25.82 nm ((Er, F) co-doped SnO 2 ) and indicated change in the porosity of the sample arising primarily from the heavy anion (F − ) doping of the system. Although such values were reported earlier [32,33], the observed mesopore size was higher than in the singly doped SnO 2 systems. (Er, F) co-doped SnO 2 at room temperature exhibited characteristic curve-type IV isotherms with distinct capillary condensation steps, suggesting uniform mesopores [32,33].…”

Core-shell nanostructured hybrid composites for volatile organic compound detection

“…The sensor arrays based on the hybrid PEDOTPIL@Fe 3 O 4 channel materials exhibited high sensitivity (1 ppm concentration) to VOC biomarkers including methanol, ethanol, acetone, benzene, and toluene, which are present in the exhaled breath of lung cancer patients. [6][7][8][9] The sensors also exhibited a high stability with a low level of noise, …”

“…A chemiresistive sensor, also referred to as an electronic nose is portable, fast, noninvasive, and highly responsive to various VOCs 2,9,24 and constitutes a robust and cost-effective solution for VOC detection. These sensors rely on changes in the electrical resistance of channel materials arising from their interaction with VOC biomarkers.…”

“…This method also has the potential to diagnose lung cancer at an early stage by detecting volatile organic compound (VOC) biomarkers in exhaled breath. [6][7][8][9] As such, a number of breath-analysis tools have been developed including gas chromatography/mass spectrometry, [10][11][12][13][14] ion flow tube mass spectrometry, 15,16 chemo-luminescence sensors, 17 optochemical fibers, 18 infrared spectroscopy, 19 and polymer-coated surface acoustic wave sensors. 20 Incorporating most of the conventional breath analysis techniques into portable sensing devices is difficult, however, owing to the bulky and expensive nature of these instruments and complexity of their operation.…”

Layer by Layer Deposition of Colloidal SnO2 Nano Particles

“…Recently, the complete processing of a SnO2-based sensor on a flexible substrate has been shown [1] along with notable advances in the control of material composition using e.g., electrospinning [2], quantum dots, and nanowires has been achieved. While intense research efforts in all of these areas are underway the use of wet-chemistry synthesized metal oxide particles in a colloidal dispersion in combination with inkjet printing offers distinct advantages because that offers a way to control most of the influencing parameter to a high degree [3].…”