Disposable lateral flow-through strip for smartphone-camera to quantitatively detect alkaline phosphatase activity in milk

• Published in: Biosensors & bioelectronics 2015-07, Vol.69, p.307-315
• Main Authors: Yu, Ling, Shi, ZhuanZhuan, Fang, Can, Zhang, YuanYuan, Liu, YingShuai, Li, ChangMing
• Format: Article
• Language: English
• Subjects: Alkaline phosphatase; Alkaline Phosphatase - analysis; Alkaline Phosphatase - chemistry; Alkaline phosphatase detection; Animals; Colorimetry - instrumentation; Disposable Equipment; Equipment Design; Equipment Failure Analysis; Food Analysis - instrumentation; Foods; Gold nanoparticle; Image Interpretation, Computer-Assisted - instrumentation; Lateral flow-through strip; Milk; Milk - chemistry; Photography - instrumentation; Point-of-care detection; Point-of-Care Testing; Portability; Raw; Reagent Strips; Sensing devices; Smartphone; Smartphones; Strip
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.02.035

A disposable lateral flow-through strip was developed for smartphone to fast one-step quantitatively detect alkaline phosphatase (ALP) activity in raw milk. The strip comprises two functional components, a conjugation pad loaded with phosphotyrosine-coated gold nanoparticles (AuNPs@Cys-Try-p) and a testing line coated with anti-phosphotryosine antibody (anti-Tyr-p mAb). The dephosphorylation activity of ALP at the testing zone can be quantitatively assayed by monitoring the accumulated AuNPs-induced color changes by smartphone camera, thus providing a highly convenient portable detection method. A trace amount of ALP as low as 0.1UL−1 with a linear dynamic range of 0.1–150UL−1 (R2=0.999) in pasteurized milk and raw milk can be one-step detected by the developed flow-through strip within 10min, demonstrating the potential of smartphone-based portable sensing device for pathogen detection. This bio-hazards free lateral flow-through testing strip can be also used to fabricate rapid, sensitive and inexpensive enzyme or immunosensors for broad portable clinic diagnosis and food contamination analysis, particularly in point-of-care and daily food quality inspection. •A disposable lateral flow strip quantitatively detects alkaline phosphatase in milk.•No biohazard reagent is utilized in strip, avoiding production of harmful wastes.•Smartphone-based image and analyze strengthen the in-field application potential.