BEIJING -- Chinese researchers have developed a 3D hand-shaped microrobot measuring about 40 micrometers, smaller than the diameter of a human hair, to achieve precise movements such as the grasping, delivering and releasing of particles or cells, according to a research article published in the International Journal of Extreme Manufacturing.

Microrobots play an essential role in early diagnosis and precision medicine, given increasing demands for controllability in bio-medicine and micromanipulation.

However, most microrobots currently consist of a single material system, with their fabrication process focused on a driving module as the main structure, the research article noted. This hinders integration of diverse functions in one microrobot, which is necessary to fulfill complex applications.

The researchers from the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences (CAS) proposed a multi-material and multi-module hand-microrobot based on femtosecond laser direct writing technology, which features a pH-responsive capturing module and a magnetic-responsive transportation module.

In deploying this microrobot for work, the researchers first put it in a liquid medium. When the surrounding pH value shifts, the microrobot's "palm" unfolds or folds like flower petals, according to the CAS. This is an intelligent stimulus response -- akin to a person's hand instinctively recoiling from hot water.

Guided by a magnetic field, this microrobot can nimbly avoid obstacles and target particles or cells. Sensing local acidification -- its "palm" snaps shut to secure objects.

The microrobot then rotates and re-orients itself to deliver the objects to the target zone. Once the medium turns alkaline, the robot unfurls its "palm" to drop off the particles or cells.

Notably, researchers expect this microrobot to be used for manipulation of cells, delivery of drugs for precise treatment, and in environmental treatment.