{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T03:38:43Z","timestamp":1780630723130,"version":"3.54.1"},"reference-count":53,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2018,5,23]],"date-time":"2018-05-23T00:00:00Z","timestamp":1527033600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Electrospun nanofiber mats have been used as sensing elements to construct piezoresistive devices due to their large surface area and high porosity. However, they have not been utilized as skin-contact supporting layers to package conductive nanofiber networks for the fabrication of piezoresistive sensors. In this work, we developed a sandwich-structured pressure sensor, which can sensitively monitor human motions and vital signs, with electrospun nanofiber mats as supporting, sensing, and packaging layers. The nanofiber mats were prepared by electrospinning with biocompatible poly (l-lactide) (PLA), silk fibroin (SF), and collagen (COL) as raw materials. The synthesized PLA\u2013SF\u2013COL mat possesses a non-woven structure with a fiber diameter of 122 \u00b1 28 nm and a film thickness of 37 \u00b1 5.3 \u03bcm. Polypyrrole (PPy) nanoparticles were grown in-situ on the mat to form a conductive layer. After stacking the pristine and conductive mats to form a PLA\u2013SF\u2013COL mat\/(PPy-coated mat)2 structure, another layer was electrospun to pack the multilayers for the construction of a sandwich-structured piezoresistive sensor. The as-prepared device can sensitively detect external pressures caused by coin loading and finger tapping\/pressing. It can also tolerate more than 600 times of pressing without affecting its sensing capability. The human body-attached experiments further demonstrate that the sensor could real-time monitor finger\/arm bending, arterial pulse, respiration rate, and speaking-caused throat vibration. The electrospinning-based fabrication may be used as a facile and low-cost strategy to produce flexible piezoresistive sensors with excellent skin-compatibility and great pressure sensing capability.<\/jats:p>","DOI":"10.3390\/polym10060575","type":"journal-article","created":{"date-parts":[[2018,5,24]],"date-time":"2018-05-24T02:55:43Z","timestamp":1527130543000},"page":"575","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":34,"title":["A Sandwich-Structured Piezoresistive Sensor with Electrospun Nanofiber Mats as Supporting, Sensing, and Packaging Layers"],"prefix":"10.3390","volume":"10","author":[{"given":"Zicong","family":"Zhao","sequence":"first","affiliation":[{"name":"Chongqing Key Laboratory for Advanced Materials &amp; Technologies of Clean Energies, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"},{"name":"Institute for Clean Energy &amp; Advanced Materials, Faculty of Materials &amp; Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bintian","family":"Li","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory for Advanced Materials &amp; Technologies of Clean Energies, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"},{"name":"Institute for Clean Energy &amp; Advanced Materials, Faculty of Materials &amp; Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liqun","family":"Xu","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory for Advanced Materials &amp; Technologies of Clean Energies, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"},{"name":"Institute for Clean Energy &amp; Advanced Materials, Faculty of Materials &amp; Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yan","family":"Qiao","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory for Advanced Materials &amp; Technologies of Clean Energies, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"},{"name":"Institute for Clean Energy &amp; Advanced Materials, Faculty of Materials &amp; Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7633-8284","authenticated-orcid":false,"given":"Feng","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China"},{"name":"Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9263-2886","authenticated-orcid":false,"given":"Qingyou","family":"Xia","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China"},{"name":"Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8879-4033","authenticated-orcid":false,"given":"Zhisong","family":"Lu","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory for Advanced Materials &amp; Technologies of Clean Energies, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"},{"name":"Institute for Clean Energy &amp; Advanced Materials, Faculty of Materials &amp; Energy, Southwest University, 1 Tiansheng Road, Chongqing 400715, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,5,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"728","DOI":"10.1038\/nmat4289","article-title":"Conformal piezoelectric systems for clinical and experimental characterization of soft tissue biomechanics","volume":"14","author":"Dagdeviren","year":"2015","journal-title":"Nat. Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4666","DOI":"10.1002\/adfm.201400379","article-title":"Wearable and highly sensitive graphene strain sensors for human motion monitoring","volume":"24","author":"Wang","year":"2014","journal-title":"Adv. Funct. Mater."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1336","DOI":"10.1002\/adma.201304248","article-title":"Silk-molded flexible, ultrasensitive, and highly stable electronic skin for monitoring human physiological signals","volume":"26","author":"Wang","year":"2014","journal-title":"Adv. Mater."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"6252","DOI":"10.1021\/acsnano.5b01613","article-title":"Stretchable, transparent, ultrasensitive, and patchable strain sensor for human-machine interfaces comprising a nanohybrid of carbon nanotubes and conductive elastomers","volume":"9","author":"Roh","year":"2015","journal-title":"ACS Nano"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"11806","DOI":"10.1039\/C5TC02173A","article-title":"Self-powered flexible pressure sensors with vertically well-aligned piezoelectric nanowire arrays for monitoring vital signs","volume":"3","author":"Chen","year":"2015","journal-title":"J. Mater. Chem. C"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1038\/nmat3380","article-title":"A flexible and highly sensitive strain-gauge sensor using reversible interlocking of nanofibres","volume":"11","author":"Pang","year":"2012","journal-title":"Nat. Mater."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"4496","DOI":"10.1038\/ncomms5496","article-title":"Conformable amplified lead zirconate titanate sensors with enhanced piezoelectric response for cutaneous pressure monitoring","volume":"5","author":"Dagdeviren","year":"2014","journal-title":"Nat. Commun."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"25609","DOI":"10.1039\/C5RA00871A","article-title":"Wearable temperature sensor based on graphene nanowalls","volume":"5","author":"Yang","year":"2015","journal-title":"RSC Adv."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.apenergy.2015.11.038","article-title":"Silk fabric-based wearable thermoelectric generator for energy harvesting from the human body","volume":"164","author":"Lu","year":"2016","journal-title":"Appl. Energy"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1500142","DOI":"10.1002\/aelm.201500142","article-title":"Flexible, stretchable and wearable multifunctional sensor array as artificial electronic skin for static and dynamic strain mapping","volume":"1","author":"Zhao","year":"2015","journal-title":"Adv. Electron. Mater."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3501","DOI":"10.1021\/nn507221f","article-title":"Nanopatterned textile-based wearable triboelectric nanogenerator","volume":"9","author":"Seung","year":"2015","journal-title":"ACS Nano"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1759","DOI":"10.1002\/adma.201200150","article-title":"A hybrid piezoelectric structure for wearable nanogenerators","volume":"24","author":"Lee","year":"2012","journal-title":"Adv. Mater."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"113903","DOI":"10.1063\/1.4869118","article-title":"Enhanced performance of wearable piezoelectric nanogenerator fabricated by two-step hydrothermal process","volume":"104","author":"Qiu","year":"2014","journal-title":"Appl. Phys. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.nanoen.2016.02.053","article-title":"An ultra-sensitive and rapid response speed graphene pressure sensors for electronic skin and health monitoring","volume":"23","author":"Lou","year":"2016","journal-title":"Nano Energy"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"095033","DOI":"10.1088\/1361-665X\/aa782d","article-title":"Flexible and wearable electronic silk fabrics for human physiological monitoring","volume":"26","author":"Mao","year":"2017","journal-title":"Smart Mater. Struct."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"825","DOI":"10.1038\/nnano.2012.192","article-title":"An electrically and mechanically self-healing composite with pressure- and flexion-sensitive properties for electronic skin applications","volume":"7","author":"Tee","year":"2012","journal-title":"Nat. Nanotechnol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"6640","DOI":"10.1002\/adma.201601572","article-title":"Carbonized silk fabric for ultrastretchable, highly sensitive, and wearable strain sensors","volume":"28","author":"Wang","year":"2016","journal-title":"Adv. Mater."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"79114","DOI":"10.1039\/C6RA16236C","article-title":"A highly stretchable strain sensor based on electrospun carbon nanofibers for human motion monitoring","volume":"6","author":"Ding","year":"2016","journal-title":"RSC Adv."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2989","DOI":"10.1016\/j.carbon.2011.03.017","article-title":"Electrical and piezoresistive properties of multi-walled carbon nanotube\/polymer composite films aligned by an electric field","volume":"49","author":"Sosa","year":"2011","journal-title":"Carbon"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"16077","DOI":"10.1021\/acsami.8b00457","article-title":"Flexible and compressible PEDOT:PSS@melamine conductive sponge prepared via one-step dip coating as piezoresistive pressure sensor for human motion detection","volume":"10","author":"Ding","year":"2018","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"18962","DOI":"10.1039\/c1jm14491j","article-title":"Electrospun pedot:Pss\u2013pva nanofiber based ultrahigh-strain sensors with controllable electrical conductivity","volume":"21","author":"Liu","year":"2011","journal-title":"J. Mater. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"17593","DOI":"10.1021\/la304240r","article-title":"Flexible tactile sensor using the reversible deformation of poly(3-hexylthiophene) nanofiber assemblies","volume":"28","author":"Gao","year":"2012","journal-title":"Langmuir"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1597","DOI":"10.1016\/j.polymer.2006.01.032","article-title":"Conductive polypyrrole nanofibers via electrospinning: Electrical and morphological properties","volume":"47","author":"Chronakis","year":"2006","journal-title":"Polymer"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3115","DOI":"10.1016\/j.biomaterials.2006.01.022","article-title":"Electrospun silk-BMP-2 scaffolds for bone tissue engineering","volume":"27","author":"Li","year":"2006","journal-title":"Biomaterials"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1289","DOI":"10.1016\/j.biomaterials.2003.08.045","article-title":"Electrospinning of silk fibroin nanofibers and its effect on the adhesion and spreading of normal human keratinocytes and fibroblasts in vitro","volume":"25","author":"Min","year":"2004","journal-title":"Biomaterials"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2821","DOI":"10.1016\/j.biomaterials.2011.01.051","article-title":"Osteoblast function on electrically conductive electrospun PLA\/MWCNTs nanofibers","volume":"32","author":"Shao","year":"2011","journal-title":"Biomaterials"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1039","DOI":"10.1016\/S0142-9612(03)00609-4","article-title":"Human bone marrow stromal cell responses on electrospun silk fibroin mats","volume":"25","author":"Jin","year":"2004","journal-title":"Biomaterials"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2685","DOI":"10.1039\/C8PY00378E","article-title":"Electrospun nanofiber reinforced composites: A review","volume":"9","author":"Jiang","year":"2018","journal-title":"Polym. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"5670","DOI":"10.1002\/anie.200604646","article-title":"Electrospinning: A fascinating method for the preparation of ultrathin fibers","volume":"46","author":"Greiner","year":"2007","journal-title":"Angew. Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"e1700838","DOI":"10.1002\/marc.201700838","article-title":"Low-density self-assembled poly(N-isopropyl acrylamide) sponges with ultrahigh and extremely fast water uptake and release","volume":"39","author":"Jiang","year":"2018","journal-title":"Macromol. Rapid Commun."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.coco.2017.10.002","article-title":"Multilevel porous structured polyvinylidene fluoride\/polyurethane fibrous membranes for ultrahigh waterproof and breathable application","volume":"6","author":"Cui","year":"2017","journal-title":"Compos. Commun."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3285","DOI":"10.1002\/anie.201611787","article-title":"Spongy gels by a top-down approach from polymer fibrous sponges","volume":"56","author":"Jiang","year":"2017","journal-title":"Angew. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.coco.2017.09.001","article-title":"Free-standing, spider-web-like polyamide\/carbon nanotube composite nanofibrous membrane impregnated with polyethyleneimine for CO2 capture","volume":"6","author":"Zainab","year":"2017","journal-title":"Compos. Commun."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"10288","DOI":"10.1039\/C7TC03456C","article-title":"Three-dimensional and ultralight sponges with tunable conductivity assembled from electrospun nanofibers for a highly sensitive tactile pressure sensor","volume":"5","author":"Xu","year":"2017","journal-title":"J. Mater. Chem. C"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"492","DOI":"10.1002\/adfm.201302344","article-title":"Spray-layer-by-layer carbon nanotube\/electrospun fiber electrodes for flexible chemiresistive sensor applications","volume":"24","author":"Saetia","year":"2014","journal-title":"Adv. Funct. Mater."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"9974","DOI":"10.1021\/acsnano.5b03510","article-title":"Stretchable array of highly sensitive pressure sensors consisting of polyaniline nanofibers and Au-coated polydimethylsiloxane micropillars","volume":"9","author":"Park","year":"2015","journal-title":"ACS Nano"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1007\/s11626-010-9381-4","article-title":"Electrospun PLGA-silk fibroin-collagen nanofibrous scaffolds for nerve tissue engineering","volume":"47","author":"Wang","year":"2011","journal-title":"In Vitro Cell. Dev. Biol. Anim."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"246","DOI":"10.1016\/j.synthmet.2008.09.012","article-title":"Bio-based conductive composites: Preparation and properties of polypyrrole (PPy)-coated silk fabrics","volume":"159","author":"Cucchi","year":"2009","journal-title":"Synth. Met."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"368","DOI":"10.1016\/j.jpowsour.2016.05.109","article-title":"Facile electrochemical polymerization of polypyrrole film applied as cathode material in dual rotating disk photo fuel cell","volume":"324","author":"Li","year":"2016","journal-title":"J. Power Sources"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1445","DOI":"10.1016\/j.carbpol.2012.07.013","article-title":"Electrospun poly(lactic acid)\/chitosan core-shell structure nanofibers from homogeneous solution","volume":"90","author":"Li","year":"2012","journal-title":"Carbohydr. Polym."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1822","DOI":"10.1016\/j.polymdegradstab.2012.05.036","article-title":"Thermal, mechanical and morphological characterization of plasticized PLA\u2013PHB blends","volume":"97","author":"Abdelwahab","year":"2012","journal-title":"Polym. Degrad. Stab."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"2775","DOI":"10.1016\/j.biomaterials.2004.07.044","article-title":"Three-dimensional aqueous-derived biomaterial scaffolds from silk fibroin","volume":"26","author":"Kim","year":"2005","journal-title":"Biomaterials"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3055","DOI":"10.1016\/j.matlet.2008.01.104","article-title":"Collagen\/hydroxyapatite composite nanofibers by electrospinning","volume":"62","author":"Teng","year":"2008","journal-title":"Mater. Lett."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"300","DOI":"10.1016\/j.colsurfa.2007.04.114","article-title":"Synthesis and characterization of polypyrrole\u2013TiO2 nanocomposites in supercritical CO2","volume":"313","author":"Yuvaraj","year":"2008","journal-title":"Colloids Surf. A"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"6","DOI":"10.4236\/snl.2011.11002","article-title":"Synthesis and characterization of polypyrrole (PPy) thin films","volume":"1","author":"Chougule","year":"2011","journal-title":"Soft Nanosci. Lett."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1353","DOI":"10.1016\/j.synthmet.2009.03.005","article-title":"Polypyrrole microstructure deposited by chemical and electrochemical methods on cotton fabrics","volume":"159","author":"Babu","year":"2009","journal-title":"Synth. Met."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1186\/1556-276X-6-431","article-title":"A facile synthesis of polypyrrole\/carbon nanotube composites with ultrathin, uniform and thickness-tunable polypyrrole shells","volume":"6","author":"Zhang","year":"2011","journal-title":"Nanoscale Res. Lett."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"486","DOI":"10.1016\/j.molstruc.2014.07.025","article-title":"Effect of graphene oxide on the structural and electrochemical behavior of polypyrrole deposited on cotton fabric","volume":"1075","author":"Yaghoubidoust","year":"2014","journal-title":"J. Mol. Struct."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"658","DOI":"10.1016\/j.matlet.2008.12.014","article-title":"Preparation of chitosan\/PLA blend micro\/nanofibers by electrospinning","volume":"63","author":"Xu","year":"2009","journal-title":"Mater. Lett."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"4657","DOI":"10.1016\/S0142-9612(02)00215-6","article-title":"Covalent immobilization of chitosan\/heparin complex with a photosensitive hetero-bifunctional crosslinking reagent on PLA surface","volume":"23","author":"Zhua","year":"2002","journal-title":"Biomaterials"},{"key":"ref_51","first-page":"91","article-title":"Structural characteristics and properties of the regenerated silk fibroin prepared from formic acid","volume":"29","author":"Um","year":"2001","journal-title":"Biomaterials"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"829","DOI":"10.1007\/s00216-009-3019-y","article-title":"Collagen types analysis and differentiation by FTIR spectroscopy","volume":"395","author":"Belbachir","year":"2009","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1016\/j.jpowsour.2008.03.029","article-title":"High-performance polypyrrole nanoparticles counter electrode for dye-sensitized solar cells","volume":"181","author":"Wu","year":"2008","journal-title":"J. Power Sources"}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/10\/6\/575\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:05:38Z","timestamp":1760195138000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/10\/6\/575"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,5,23]]},"references-count":53,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2018,6]]}},"alternative-id":["polym10060575"],"URL":"https:\/\/doi.org\/10.3390\/polym10060575","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,5,23]]}}}