Aptamer-Assisted Acoustophoresis for Microfluidic Separation of Gram-Negative Bacteria

Take a microfluidic acoustophoretic chip, a sound-wave-based particle separator with two inlets and two outlets connected to plastic tubes.

Inject Gram-negative and Gram-positive bacteria, along with aptamer-coated microbeads, through the sample inlet.

Inject a buffer through the buffer inlet at high pressure to maintain side-by-side flow.

Inside the microchannel, the lipopolysaccharides on the Gram-negative bacterial membrane bind to the short single-stranded DNA aptamers on the microbeads.

Gram-positive bacteria, which lack lipopolysaccharides, do not bind.

As the flow continues, activate the piezoelectric transducer to generate acoustic waves that create pressure nodes across the channel.

These waves push large microbeads bound to Gram-negative bacteria toward the center, where they are collected at the target outlet.

Unbound small-sized Gram-positive bacteria remain unaffected and flow sideways to the waste outlet.

Microscopic imaging shows an increased signal from Gram-negative bacteria-bound beads at the target outlet, confirming their selective separation by aptamer-assisted acoustophoresis.

Connect PEEK tubes to the two inlets for injecting two samples and buffer, and the two outlet