Droplet controllable operation has wide applications
in microfluidics, biomedicine, microreactors, and other fields. Droplets
can spontaneously transfer from a high-energy state to a low-energy
state, but how to reverse transfer the droplets is a difficult task.
In this article, we use a special hydrophilic–hydrophobic interphase
structure (HHIS) to achieve this reverse transfer. We specifically
study the critical conditions under which droplet transfer can be
achieved. The length of the hydrophilic surface in this structure
and the hydrophilic/hydrophobic properties of the surface must be
in the appropriate range. Based on this, an optimized structure used
to transfer droplets was designed. Finally, we carried out research
on biological applications and successfully achieved the transfer
of droplets from zebrafish eggs and zebrafish larvae. This unique
method is low-cost, biofriendly, and highly applicable to various
surfaces, illustrating the great potential in chemical and biological
analysis.