Mechanical testing on the MNAs was conducted using a Q800 Dynamic
Mechanical Analysis (DMA) system (TA Instruments, New Castle, DE) equipped with
a compression clamp. Samples were compressed at a rate of 0.1 N
min−1 until the failure was confirmed via optical
microscopy. Values for E and σγof MNAs were calculated from the linear region of the resulting stress-strain
curve. To evaluate the puncture ability of the MNAs, hydrogels with different
stiffness were prepared by mixing agarose gel powder in 1% PBS (Sigma-Aldrich,
Saint Louis, MO) at four different concentration levels: 1.2%, 2.4%, 5%, and
10%. The solutions were heated to a boiling temperature and then cooled down
until the hydrogels were set at room temperature. Before each MNA puncture, the
top surface of the hydrogel was rinsed with PBS. The MNA was mounted on a
stereotaxic manipulator, slowly inserted into the hydrogel samples, and
optically monitored for any signs of failure.
Mechanical Analysis (DMA) system (TA Instruments, New Castle, DE) equipped with
a compression clamp. Samples were compressed at a rate of 0.1 N
min−1 until the failure was confirmed via optical
microscopy. Values for E and σγof MNAs were calculated from the linear region of the resulting stress-strain
curve. To evaluate the puncture ability of the MNAs, hydrogels with different
stiffness were prepared by mixing agarose gel powder in 1% PBS (Sigma-Aldrich,
Saint Louis, MO) at four different concentration levels: 1.2%, 2.4%, 5%, and
10%. The solutions were heated to a boiling temperature and then cooled down
until the hydrogels were set at room temperature. Before each MNA puncture, the
top surface of the hydrogel was rinsed with PBS. The MNA was mounted on a
stereotaxic manipulator, slowly inserted into the hydrogel samples, and
optically monitored for any signs of failure.