A microfluidic microinjector for toxicological and developmental studies in Drosophila embryos

Area of Science:

• Developmental biology
• Biotechnology
• Microfluidics

Background:

• Microinjection is crucial for delivering reagents into model organisms like Drosophila embryos.
• Existing microinjection systems lack precision in targeting specific locations within embryos.
• Accurate reagent delivery is essential for studying embryonic development and toxin effects.

Purpose of the Study:

• To demonstrate a new polydimethylsiloxane (PDMS)-based microinjection system for precise reagent delivery into Drosophila embryos.
• To investigate the effects of sodium azide (NaN3) on cardiogenesis in Drosophila embryos using the developed system.
• To establish a method for quantifying toxin-induced changes in cardioblast migration and heart assembly.

Main Methods:

• Development of a compliant mechanism-based PDMS microinjection system.
• Precise insertion of a microneedle into Drosophila embryos with 5 μm resolution.
• Delivery of low volumes (30 pL) with ±10 pL accuracy using pressure pulses.
• Injection of varying doses of sodium azide (NaN3) and Rhodamine B into embryos.

Main Results:

• The system achieved precise lateral insertion up to 250 μm within Drosophila embryos.
• Sodium azide (NaN3) injection significantly decreased cardioblast (CB) migration velocity and filopodia number at concentrations above 10 mM.
• Rhodamine B injections (0 mM NaN3) showed no significant difference compared to uninjected controls.
• Quantified the dose-sensitive effects of NaN3 on heart assembly for the first time.

Conclusions:

• The developed PDMS microinjection system offers high precision for reagent delivery in Drosophila embryos.
• This technology enables accurate quantification of toxin effects on embryonic development, specifically cardiogenesis.
• The system holds potential for various embryonic assays requiring targeted reagent delivery.