Smartphone-based label-free nanosensor for acrylamide detection in drinking water

Overview

This solution offers a portable, label-free detection platform for acrylamide, a probable carcinogen that can form in drinking water during certain industrial and treatment processes. By combining aptamer-functionalized nanopore sensors with a smartphone-based portable spectrometer, the platform aims to deliver results in approximately 5 minutes at a target cost of about $1 per sensor. The approach is intended for rapid, on-site water safety screening, enabling timely decision-making without the need for centralized laboratory infrastructure.

Technical specifications

• Aptamer-based recognition: Uses short, single-stranded DNA or RNA aptamers selected for high affinity and specificity to acrylamide, enabling molecular recognition without radioactive or fluorescent labels.
• Nanopore sensor surface: Each nanopore is functionalized with acrylamide-specific aptamers; target binding alters the optical interference fringes on the sensor surface.
• Optical readout: Changes in interference fringes are captured by a portable spectrometer connected to a smartphone, providing a quantitative readout on-site.
• Microfluidic chip format: The sensor is integrated into a microfluidic chip to handle small water samples and reduce reagent use.
• Aptamer discovery pipeline: When suitable aptamers are not available, the team applies a structure-switching systematic evolution of ligands by exponential enrichment (SELEX) method to identify new high-specificity aptamers.
• Performance targets: Sensitivity, specificity, and reliability are optimized to minimize nonspecific binding and to support detection at relevant concentrations for drinking water monitoring.
• Prior validated analogs: The team has previously demonstrated aptamer-based label-free nanosensors for plant hormones salicylic acid (detection down to 0.1 µM) and abscisic acid, supporting technical feasibility of the acrylamide platform.

Technology readiness level

The platform is at an early-to-mid development stage. Core components, including aptamer-based label-free nanopore sensing, microfluidic chip fabrication, and smartphone-based spectral readout, have been demonstrated individually in the team's prior work on salicylic acid and abscisic acid detection. The acrylamide-specific platform requires integration of available acrylamide aptamers with the nanosensor and spectrometer, fabrication and functionalization of the microfluidic chip, and performance evaluation using serial dilutions of acrylamide. The project is planned as a one-year development effort, with validation focused on sensitivity, specificity, and on-site usability in drinking water samples before progressing toward field deployment.