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Cheng et al. Soft Sci. 2026, 6, 36 Page 3 of 15

is a clear demand for sensors that are able to seamlessly integrate into daily textiles. Currently, there are only
a few reports on cortisol-sensing textiles , and their technological routes mainly include conventional
[18]
coating as well as chemical and electrochemical deposition . On the one hand, they significantly
[19]
compromise the inherent advantages of textiles, including softness, conformability to skin, and moisture
absorption. This greatly diminishes comfort and long-term wearability. On the other hand, the reported
preparation routes are multi-step and discontinuous, typically including the preparation of conductive textile
substrates followed by the deposition of functional layers in sequence.

Herein, we designed dual-function core-shell nickel hexacyanoferrate-MIP (NiHCF-MIP) nanomaterials and
presented a scalable continuous conjugate electrospinning technology. Using this approach, we obtained
coaxial sensing yarns that are capable of real-time monitoring of sweat cortisol. The coaxial yarn shows high
specificity to cortisol, a high sensitivity of 2.08 μA·dec , and a low LOD of 0.4 nmol/L. The dual-function
-1
core-shell NiHCF-MIP NCs integrate redox-probing cores with cortisol-recognizing shells, which is
beneficial for signal transport and also enables one-step continuous production [Figure 1A]. In addition, the
coaxial configuration produced by conjugate electrospinning [20,21] , with conductive yarns as the core and
cortisol-sensing nanofibers as the cortex, combines conductivity, flexibility, and sensing capability .
[22]
Furthermore, the porous morphology of the nanofiber cortex enhances sweat absorption and interfacial
contact [Figure 1B]. This work will facilitate the construction of a wearable biosensing platform for
personalized stress and health assessments [Figure 1C], as well as provide a commercially viable technical
methodology.

EXPERIMENTAL
Reagents and materials
Ferrous acetate (Fe(CH COO) ), nickel(II) acetate tetrahydrate (Ni(CH COO) ·4H O), trisodium citrate
2
2
3
2
3
dihydrate (Na Cit·2H O), potassium ferricyanide (K [Fe(CN) ]), acetic acid, cortisol, pyrrole (Py), methanol,
2
3
6
3
urea, ethylene glycol dimethacrylate (EGDMA), 2,2-azobis(isobutyronitrile) (AIBN), ascorbic acid (AA),
phosphate-buffered saline (PBS), Artificial sweat, and N, N-dimethylformamide (DMF) were purchased
from Macklin Co., Ltd. (Shanghai, China). Polyacrylonitrile (PAN, Mw 85,000), poloxamer (F127),
Progesterone, cortisone, prednisolone, corticosterone, creatinine, and multiwall carbon nanotubes
(MWCNTs, OD: 8-15 nm, length: 50 μm) were purchased from Aladdin Co., Ltd. (Shanghai, China).
Thermoplastic polyurethane (TPU) was provided by BASF Co., Ltd. (Shanghai, China). Conductive carbon
threads were from Taobao.
Preparation of NiHCF NCs
The redox probe nanomaterial prepared herein is a type of Prussian blue analogue, specifically nickel
hexacyanoferrate nanocubes (NiHCF NCs). A modified low-temperature coprecipitation reaction method
was proposed . At first, 600 μmol of Fe(CH COO) and 900 μmol of Na Cit·2H O were dissolved in 20 mL
[23]
3
2
3
2
of deionized water to form solution A, while 400 μmol of K [Fe(CN) ] was dissolved in another 20 mL of
6
3
deionized water to prepare solution B. Solution A was then added dropwise to solution B at a flow rate of
20 mL/min under continuous stirring at 1,000 r/min, followed by a coprecipitation reaction at a low
temperature of 5 °C for 24 h. The resulting precipitate was collected by centrifugation at 11,000 r/min for 10
min. The pellet was washed four times with 60 mL of deionized water. Finally, the purified product was dried
in a vacuum oven at 40 °C for 12 h to obtain NiHCF NCs.
Preparation of dual-function core-shell NiHCF-MIP NCs
The core-shell NiHCF-MIP NCs were prepared via thermally initiated free radical copolymerization ,
[24]
employing pyrrole as the functional monomer and EGDMA as the cross-linker, to construct a molecularly
imprinted polymer (MIP) network, followed by a cortisol elution process [Figure 1A]. Pyrrole primarily