Page 46 - Read Online

Ma et al. Soft Sci 2024;4:26 https://dx.doi.org/10.20517/ss.2024.20 Page 23 of 34

Table 4. Summary of typical LIG-based biochemical sensors for healthcare
LIG Analytes Performance Applications Ref.
composites/substrate
PANI@LIG (E)/PI/Ecoflex pH Sensitivity: -53 mV/pH NA [41]
PEDOT@LIG (E)/PI Dopamine Sensitivity: 0.22 ± 0.01 μA/μM NA [75]
-1 -2
Ni@LIG (E), Glucose Sensitivity: 1,080 μA·mM ·cm Accurate glucose measurements from the human [40]
Au@LIG (E)/PI sweat
FeNCs@LIG (E)/PI Tyr, UA Detection limit: Tyr, 5.11 μM; Accurate detection of Tyr and UA in sweat [103]
UA 1.37 μM
LIG (E)/PI Cortisol Assay time: < 1 min Efficient cortisol sensing in human sweat and saliva [43]
-1
LIG (E)/PI/Ecoflex NOx Sensitivity: NO, 4.18‰ ppm ; Accurately classify patients with respiratory diseases [39]
-1
NO , 6.66‰ ppm from healthy human subjects
2
LIG (S, E)/PI Temperature, Sensitivity: Gout monitoring in patients and healthy controls [42]
-1
respiration rate, temperature: -0.06% °C ;
-1 -2
Tyr, UA UA, 3.50 μA·μM ·cm ;
-1 -2
Tyr, 0.61 μA·μM ·cm
LIG (S, E)/PI Strain, pressure, Sensitivity: strain, 2.277; Depicts the human-ambience interface amid the [107]
-1
temperature, pressure, 2.23 MPa ; laboratory and exercising atmosphere
-1
proximity, ECG, temperature, -514.06 ppm °C ;
+ -1
EMG, TENG, Na , proximity, 1.93% mm ;
+ pH, -60.91 mV/pH
H , Acetone gas, NO 2
LIG: Laser-induced-graphene; PANI: polyaniline; PI: polyimides; PEDOT: poly(3,4-ethylenedioxythiophene); FeNCs: iron nano-catalysts; Tyr:
tyrosine; UA: uric acid; ECG: electrocardiography; EMG: electromyography; TENG: triboelectric nanogenerator.
covered the frequency range of human voice. Meanwhile, the intelligent AT produced sound through the
thermoacoustic effect, converting mechanical information into speech. Driven by a safe voltage of 5 V, the
intelligent AT could generate sounds in the 100-20 kHz range and around 60 dB. By incorporating an
artificial intelligence model, the intelligent AT device recognized daily words spoken by a patient with a
laryngectomy, achieving a high accuracy (> 90%) [Figure 12F]. Furthermore, the recognized words were
synthesized into speech and displayed on the AT to rehabilitate the vocalization capability of patients.

Meanwhile, Sun et al. developed a LIG-based dual-function acoustic transducer containing a triboelectric
artificial ear and a thermoacoustic artificial mouth [Figure 12G] . The designed acoustic transducer
[108]
consisted of three layers: a multi-hole PI sheet with double-side-patterned LIG, a PET ring spacer, and a PI
film with one-side-patterned LIG. The input alternating electrical energy was converted into periodic joule
heat energy by the thermoacoustic LIG, shrinking air and generating audio waves [Figure 12H]. The
fabricated device exhibited ultrahigh sensitivity of 4,500 mV·Pa , a high resolution of 0.005 Hz, and
-1
excellent stability (70-115 dB). Using machine learning, the acoustic transducer could recognize
multidimensional speeches with a high accuracy of 96.63% [Figure 12I]. In addition, the device could be
utilized for artificial intelligence communication based on detected speech features. Typical LIG-based soft
bio-actuators for intelligent healthcare are summarized in Table 5.

2
LIGS E for power supply
Power supply devices
Thanks to the fast development of wearable devices and Micro-electromechanical Systems (MEMS)
products, there is an urgent demand for soft energy storage devices used for wearable electronics [109-112] .
Batteries, fuel cells, and supercapacitors play important roles in electrochemical energy conversion and
storage, and TENG provides an effective strategy for mechanical energy conversion [113-119] . The LIG
electrodes can enhance their performance from the following aspects: (1) the porous LIG electrodes increase
the contact area between electrode and electrolyte, resulting in the improvement of specific capacitance; (2)