PMMA biosensor for nucleic acids with integrated mixer and electrochemical detection

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Polymer-based biosensors offer cost-effectiveness and disposability for diagnostics.
• Sensitive detection of Cryptosporidium parvum mRNA is crucial for water quality monitoring and public health.

Purpose of the Study:

• To design, fabricate, and utilize a novel electrochemical biosensor on a poly(methyl methacrylate) (PMMA) substrate.
• To achieve sensitive detection of amplified hsp70 mRNA from Cryptosporidium parvum.

Main Methods:

• Microfluidic channels and interdigitated ultramicroelectrode arrays (IDUA) were fabricated on PMMA using hot embossing and photolithography.
• Surface functionalization involved UV treatment, cystamine conjugation, and gold evaporation.
• Amperometric detection was performed using a sandwich hybridization assay with superparamagnetic beads and liposome reporters.

Main Results:

• UV functionalization yielded a carboxylic acid density of ~8 nmol/cm(2) on PMMA.
• UV-assisted thermal bonding improved capillary flow by reducing the water contact angle.
• The PMMA biosensor detected amplified hsp70 mRNA from a single Cryptosporidium parvum oocyst.

Conclusions:

• A disposable, cost-effective PMMA-based electrochemical biosensor was successfully developed.
• The biosensor demonstrates high sensitivity for detecting Cryptosporidium parvum mRNA.
• This technology holds promise for rapid and sensitive pathogen detection in environmental or clinical samples.