A paper-based chemiresistive biosensor employing single-walled carbon nanotubes for low-cost, point-of-care detection

• Published in: Biosensors & bioelectronics 2019-04, Vol.130, p.367-373
• Main Authors: Shen, Yu, Tran, Thien-Toan, Modha, Sidharth, Tsutsui, Hideaki, Mulchandani, Ashok
• Format: Article
• Language: English
• Subjects: Biosensing Techniques; Biosensors; Carboxylic Acids - chemistry; Chemiresistive; Humans; Limit of Detection; Low-cost; Nanotubes, Carbon - chemistry; Paper-based; Point-of-care; Point-of-Care Systems; Pyrenes - chemistry; Serum Albumin, Human - chemistry; Serum Albumin, Human - isolation & purification; Single-walled carbon nanotubes
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2018.09.041

Paper-based biosensors are promising for low-cost diagnostics. However, its widespread use has been hampered due to a lack of sensitive detection methods that can be easily implemented on paper substrates. On the other hand, single-walled carbon nanotubes (SWNTs) -based chemiresistive biosensors are gaining popularity as label-free, highly sensitive biosensors. However, traditional SWNT-based chemiresistors need to be more affordable for use in resource-limited settings. In this study, we report fabrication, optimization and analytical characterization of a chemiresistive biosensor on paper for label-free immunosensing. We synthesized a water-based ink using pyrene carboxylic acid (PCA) through non-covalent π-π stacking interaction between PCA and SWNTs. The PCA/SWNTs ink concentration can reach ~4 mg mL−1 and was stable at room temperature for one month. We introduced a combination of wax printing and vacuum filtration to fabricate the hydrophilic channels and the well-defined PCA/SWNTs ink deposition on paper in a facile manner requiring no additional masks or stencils. Specific antibodies were then functionalized on the PCA/SWNTs. Quantitative and selective detection of human serum albumin (HSA) is demonstrated with a limit of detection (LOD) of 1 pM. This low LOD is attributed to the porous structure of the paper surface, which can accommodate more SWNTs. Furthermore, the hydroxyl group-containing cellulose fibers help connect the SWNTs into an electrical network. The paper-based chemiresistive biosensor proposed here is easy to fabricate, and designed for rapid, sensitive and selective detection of HSA. This work provides a potential platform for automated, disposable paper-based biosensors with multiplexed detection capability and microfluidic controls. •Low-cost, label-free SWNTs-based chemiresistive biosensor on paper is reported.•Simple, fast, stencil-free wax printing and vacuum filtration used for fabrication.•High concentration, stable, water-based SWNTs ink defines sensing channel.•Bioreceptor immobilized covalently on SWNTs by zero-length crosslinking chemistry.•Highly sensitive, selective, label-free human serum albumin detection demonstrated.