Fully Automated Field-Deployable Bioaerosol Monitoring. System using Carbon Nanotube-based Biosensors

Transcription

1 Supporting Information Fully Automated Field-Deployable Bioaerosol Monitoring System using Carbon Nanotube-based Biosensors Junhyup Kim, Joon-Hyung Jin, Hyun Soo Kim, Wonbin Song, Su-Kyoung Shin, Hana Yi, Dae-Ho Jang, Sehyun Shin, and Byung Yang Lee * Department of Mechanical Engineering, Korea University, Seoul 02841, Korea BK21PLUS Program in Embodiment: Health-Society Interaction, Department of Public Health Sciences, Graduate School, Korea University, Seoul 02841, Korea *To whom correspondence should be addressed: blee@korea.ac.kr, Tel: pages, 11 figures S1

2 Figure S1. Basic electrical characteristics of CNT-FET devices. (A) Photo image of a CNT-FET device. (B) Optical image of a CNT-FET device. (C) Typical I-V characteristic curve of a CNT- FET device. (D) Resistance distribution of CNT-FET devices. (E) On-off ratio of a CNT-FET device. (F) Liquid gate characteristics of a CNT-FET device. S2

3 Figure S2. Fluorescence image of a CNT-FET with no primary antibody immobilized. First, A. alternata solution (1 µg/ml) was injected on a CNT-FET without primary antibody. After washing with PBS, FITC-labeled antibody (1/1000 diluted in H 2 O) was incubated for 1 min. Then, the sample was further washed to remove any unbinding FITC-labeled antibody. The image was taken just after washing. Without the primary antibodies immobilized on the CNTs, the CNT region showed no significant fluorescence intensity compared to the background. The bright fluorescence lines along the electrode edges are due to increased light scattering on those regions. S3

4 Figure S3. Real-time response of A. niger-specific sensor. A. niger antibody (WF-AF 1) was immobilized on the CNT channel. Initially, 2 µl of 1 mm ph 7.4 PBS buffer was applied to the sensor. Afterwards, 2 µl droplets of A. niger suspended in 1 mm ph 7.4 PBS solution of different concentrations (shown in graph) was injected in 50 sec intervals. Here, the source-drain voltage was kept at V ds = 0.1 V. S4

5 Figure S4. Liquid gate characteristics of A. niger-specific sensor. The initial volume was 10 µl of 1 mm ph 7.4 PBS buffer. Afterwards, 5 µl of 10 pg/ml A. alternata and A. niger were successively applied. The gate transfer curve shifted upward towards increased conductance only at the injection of the target A. niger. The source-drain voltage was maintained at V ds = 0.1 V. S5

6 . Figure S5. (A) Photo image showing the BAMI composed of bioaerosol sampler (BioSampler, SKC), pumping assembly, Peltier cooler, and CNT-FET sensor module. (B) Fluid channelintegrated CNT-FET sensor module for monitoring bioaerosols. The sensor holder (1) and (2) is composed of two parts. The upper part (1) made of polyether ether ketone has microfluidic channels through which the sampled solution is separately supplied to each channel of the CNT- FET device. The lower part (2) is made of heat-conductive aluminum through which silicon tubing pass for each CNT-FET channel. It also makes the sampled solution to precool effectively before injection to CNT-FETs. The CNT-FET sensor is located between the two parts and tightly joined with a holder joint screw (3). Right underneath the lower part of the holder, Peltier cooler (4) and the heat sink (5) are positioned in order. S6

7 Figure S6. BAMI system response to ammonium hydroxide. Ammonium hydroxide solutions of known concentration were injected directly into the sampler vessel. The ammonium hydroxide reached the CNT-FET within 10 sec. S7

8 Figure S7. Selectivity of A. niger sensor. Normalized conductance of the A. niger sensor was observed when exposed to fungi other than the target A. niger. Black signal is control experiment where only PBS was applied. Red and blue signals represent the signals when exposed to A. alternata and C. cladosporioides, respectively. S8

9 Figure S8. Chamber test using BAMI system. (A) BAMI system placed in a homemade acryl chamber and dish-cultured fungi source. (B) Real-time response and regeneration of BAMI for the detection of fungal allergens, A. niger and A. alternata. BAMI system was operated at 4 C, followed by subsequent regeneration process of the CNT-FET device. Black, red, and blue circles were obtained by pure PBS, A. niger-containing PBS, and A. alternata-containing PBS solutions, respectively. Note that the latter half of red and blue circles was obtained by switching the allergen-containing PBS into a pure PBS. S9

10 Figure S9. Optical images of field test location for BAMI system. (Left) Residential room located in upper level floor. (Right) Residential room located in basement floor. S10

11 Figure S10. Morphological analysis of Aspergillus and Alternaria species for samples collected from the field test locations using conventional impactor. Optical (A) and SEM (B) images of Aspergillus species. Optical image (C) and magnified view (D) of Alternata species. S11

12 Figure S11. Sensor response to filtered solution. This control experiment was performed to observe the effect of ambient pollutants such as gases and dust particles to the sensor response. Ambient indoor air was sampled using the Biosampler TM at 12.5 L/min aspiration rate for 5 min to prepare a bioaerosol solution in PBS buffer in the same way as Figure 7. The solution was then filtered with 0.02 µm pore size filter (Anodisc 47, Whatman, USA) to eliminate any particles larger than 0.02 µm including fungal spores and their fragments. The sensor was an A. niger sensor with antibody WF-AF-1 immobilized on the CNT-FET. The graph shows that the sensor does not respond to a filtered solution. This shows that the sensor response is not due to ambient gases or particles smaller than 0.02 µm in size. S12