Copolymerization Of E-caprolactone Research Articles

Synthesis of lipid‐modified copolymers based on caprolactone via enzymatic ring‐opening polymerization and click chemistry and evaluation of their potential as vehicles in drug delivery

AbstractThis research focuses on the application of click chemistry to the synthesis of amphiphilic lipidic copolymers with a target number of oleyl, cholesteryl, and linoleic pendant groups. The synthesis was performed using a two‐step approach. In the first step, copolymerization of ε‐caprolactone (CL) and α‐azido‐caprolactone (N3CL) was carried out using enzymatic ring‐opening polymerization (eROP) catalyzed by Candida Antarctica lipase B (CALB). This resulted in copolymers with an average molecular weight of 9.53 kDa, each containing approximately seven azide groups per chain. Subsequently, click chemistry was utilized to react P(N3CL‐co‐CL) copolymers with propargylated lipidic compounds, achieving azide group consumption higher than 88%. These lipidic copolymers exhibited reduced crystallinity, as evidenced by their lower melting enthalpy values. In addition, these materials were evaluated for the fabrication of nanostructured vehicles for curcumin (Cur@NP) using the solvent emulsion‐evaporation methodology. The lipidic copolymers demonstrated enhanced encapsulation efficiencies and drug loading capacities of 25 and 12%, respectively, tunable particle sizes in the range of 260–420 nm, and controlled release profiles over 30 h. Cur@NPs demonstrated notable antioxidant and antibacterial activities, particularly against Gram‐positive bacteria such as Staphylococcus aureus, achieving efficiencies close to 50%.

Regulation of ester contents enabled tunable thermal and mechanical properties of poly(ester amide)

AbstractPoly(ε‐caprolactone‐co‐ε‐caprolactam) was synthesized through ring‐opening copolymerization of ε‐caprolactone (CLO) and ε‐caprolactam catalyzed by ethylmagnesium bromide (EtMgBr) or sodium ε‐caprolactam. Varied ester contents were achieved from 0 to 100 mol%. EtMgBr enabled the copolymerization with high yield of over 95%. Thermal properties vary with different ester contents. With increasing CLO content, the onset decomposition temperature (273.36 to 240.97 °C) and glass transition temperature (52.1 to −56.3 °C) gradually decreased. The results of melting behavior of resultant poly(ester amide)s through differential scanning calorimetry and theoretical calculation indicated a eutectic temperature of 46.6 °C. The mechanical properties of obtained copolymers were systematically investigated. The enhancement of CLO incorporation led to a decrease in tensile strength (70.99 to 9.88 MPa) and Young's modulus (690.03 to 19.18 MPa). Copolymer with CLO incorporation of 70 mol% exhibited a eutectic temperature of 46.6 °C, and enabled a high elongation at break (658%) and enhanced impact strength (138.5 kJ m−2). © 2023 Society of Chemical Industry.

The Novel Gallium Aminobisphenolate Initiator of the Ring-Opening Copolymerization of L-Lactide and ε-Caprolactone: A Computational Study.

Density functional theory (DFT) simulations of ring-opening copolymerization of ε-caprolactone (CL) and L-lactide (LA) in presence of novel gallium complex on aminobis (phenolate) ligand are conducted. The initial steps of polymerization of CL and LA as well as the first steps of propagation which led to LGa-LA-LA-OMe, LGa-LA-CL-OMe, LGa-CL-LA-OMe, or LGa-CL-CL-OMe derivatives have been analyzed in detail. According to these data, the studied catalyst is a rare example of a catalyst in which, during copolymerization, the polymerization of CL should proceed faster than LA. Thus, we predict the formation of a mainly block copolymer poly(CL-block-LA) using this catalyst.

Mono(imidazolin-2-iminato) Hafnium Complexes: Synthesis and Application in the Ring-Opening Polymerization of ε-Caprolactone and rac-Lactide

Mono-substituted imidazolinX-2-iminato hafnium(IV) complexes (X = iPr, tBu, Mesityl, Dipp) were synthesized and fully characterized, including solid-state X-ray diffraction analysis. When the X group is small (iPr), a dimeric structure is obtained. In all the monomeric complexes, the Hf-N bond can be regarded as a double bond with similar electronic properties. The main difference among the monomeric complexes is the cone angle of the ligand, which induces varying steric hindrances around the metal center. When the monomeric complex of mono(bis(diisopropylphenyl)imidazolin-2-iminato) hafnium tribenzyl was reacted with three equivalents (equiv) of iPrOH, the benzyl groups were easily replaced, forming the corresponding tri-isopropoxide complex. However, when BnOH was used, dimeric complexes were obtained. When five equivalents of the corresponding alcohols (BnOH, iPrOH) were reacted with the monomeric complex, different dimeric complexes were obtained. Regardless of the high oxophilicity of the hafnium complexes, all complexes were active catalysts for the ring-opening polymerization (ROP) of ε-caprolactone. Dimeric complexes 5 and 6 were found to be the most active catalysts, enabling polymerization to occur in a living, immortal fashion, as well as the copolymerization of ε-caprolactone with rac-lactide, producing block copolymer PCL-b-LAC. The introduction of imidazolin-2-iminato ligands enables the tailoring of the oxophilicity of the complexes, allowing them to be active in catalytic processes with oxygen-containing substrates.

Precise Tuning and Characterization of Viscoelastic Interfaces for the Study of Early Epithelial-Mesenchymal Transition Behaviors.

There is growing evidence that cellular functions are regulated by the viscoelastic nature of surrounding matrices. This study aimed to investigate the impact of interfacial viscoelasticity on adhesion and epithelial-mesenchymal transition (EMT) behaviors of epithelial cells. The interfacial viscoelasticity was manipulated using spin-coated thin films composed of copolymers of ε-caprolactone and d,l-lactide photo-cross-linked with benzophenone, whose mechanical properties were characterized using atomic force microscopy and a rheometer. The critical range for the morphological transition of epithelial Madin-Darby canine kidney (MDCK) cells was of the order of 102 ms relaxation time, which was 1-2 orders of magnitude smaller than the relaxation times reported (10-102 s). An analysis of strain rate-dependent viscoelastic properties revealed that the difference was caused by the different strain rate/frequency used for the mechanical characterization of the interface and bulk. Furthermore, decoupling of the interfacial viscous and elastic terms demonstrated that E/N-cadherin expression levels were regulated differently by interfacial relaxation and elasticity. These results confirm the significance of precise manipulation and characterization of interfacial viscoelasticity in mechanobiology studies on EMT progression.

Hydrophilic and degradable polylactones via copolymerization of ε-caprolactone and oxo-crown ether catalyzed by a bifunctional organic base

Poly(ε-caprolactone) (PCL) has been one of the most important biomaterials, but its instinct hydrophobicity and slow biodegradation limit its broad applications. Herein, copolymerization of CL and a hydrophilic macrolactone, 2-oxo-15-crown-5 ether (O15C), was achieved through ring opening polymerization catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) using benzyl alcohol as the initiator at room temperature. A series of poly(CL-co-O15C) copolymers with different O15C contents were prepared by simply tuning the feeding ratio of [CL]/[O15C]. They showed molecular weights ranging from 11.0 to 20.6 kg mol−1, and polydispersity index between 1.4 and 1.6, characterized by SEC (Size Exclusion Chromatography). Analysis of 1H NMR indicated that the copolymers belong to a random copolymer structure. The introduction of O15C had a significant influence on thermal stability, hydrophilicity and degradability of the copolymers. With increasing the O15C content, the crystalline ability of PCL segment among the copolymers reduced, while the hydrophilic property was improved obviously. Through hydrolysis experiment, the poly(CL-co-O15C) with O15C content of 38 mol% exhibited a much faster degradable rate than that of the copolymer with O15C content of 10 mol%. Therefore, copolymerization of CL with a crown ether monomer via organic catalyst mediated ROP will be a feasible strategy for modification of polyester materials.

Viscoelastically tunable substrates elucidate the interface-relaxation-dependent adhesion and assembly behaviors of epithelial cells

Recent progress in mechanobiology sheds light on the regulation of cellular phenotypes by dissipative property of matrices, i.e., viscosity, fluidity, and stress relaxation, in addition to extensively studied elasticity. However, most researches have focused on bulk mechanics, despite cells in 2D culture can only interact with matrix interface directly. Here, we studied the impact of interfacial viscosity as well as elasticity of substrates on the early stage of adhesion behaviors of epithelial cells through new material design and mechanical characterization. The materials are copolymers of ε-caprolactone and d,l-lactide photocrosslinked by benzophenone. The substrate viscoelasticity changes depending on the polymer molecular weight and irradiation time. The interfacial elasticity and relaxation were determined by atomic force microscopy with modes of nanoindentation and tip-dwelling, respectively. MDCK cells changed morphologically, ranging from loose beaded assembly to more compact spheroids and eventual spread monolayer clusters, in response to the interfacial viscoelasticity change. Such morphological changes were mainly determined by substrate interfacial relaxation, rather than interfacial elasticity. Single-cell tracking identified biphasic motility with the minimum speed at intermediate relaxation time (~350 ms), where cells showed transitional morphologies between epithelial and mesenchymal traits. In that relaxation level, partially deformed cells moved around to coalesce with surrounding cells, eventually assembling into compact cellular aggregates. These results highlight, unlike the conventional hanging-drop technique, an appropriate level of interfacial relaxation is critical for efficient cell aggregate maturation on adhesive viscoelastic matrices. This work not only elucidates that the interfacial relaxation as the essential mechanical parameter for epithelial cell adhesion and migration, but also gives useful tips for creating physiologically relevant drug screening platform.

Achievements and Trends in Biocatalytic Synthesis of Specialty Polymers from Biomass-Derived Monomers Using Lipases

New technologies for the conversion of biomass into high-value chemicals, including polymers and plastics, is a must and a challenge. The development of green processes in the last decade involved a continuous increase of the interest towards the synthesis of polymers using in vitro biocatalysis. Among the remarkable diversity of new bio-based polymeric products meeting the criteria of sustainability, biocompatibility, and eco-friendliness, a wide range of polyesters with shorter chain length were obtained and characterized, targeting biomedical and cosmetic applications. In this review, selected examples of such specialty polymers are presented, highlighting the recent developments concerning the use of lipases, mostly in immobilized form, for the green synthesis of ε-caprolactone co-polymers, polyesters with itaconate or furan units, estolides, and polyesteramides. The significant process parameters influencing the average molecular weights and other characteristics are discussed, revealing the advantages and limitations of biocatalytic processes for the synthesis of these bio-based polymers.

In Vitro and In Vivo Studies of Biodegradability and Biocompatibility of Poly(εCL)-b-Poly(EtOEP)-Based Films.

The control of surface bioadhesive properties of the subcutaneous implants is essential for the development of biosensors and controlled drug release devices. Poly(alkyl ethylene phosphate)-based (co)polymers are structurally versatile, biocompatible and biodegradable, and may be regarded as an alternative to poly(ethylene glycol) (PEG) copolymers in the creation of antiadhesive materials. The present work reports the synthesis of block copolymers of ε-caprolactone (εCL) and 2-ethoxy-1,3,2-dioxaphospholane-2-oxide (ethyl ethylene phosphate, EtOEP) with different content of EtOEP fragments, preparation of polymer films, and the results of the study of the impact of EtOEP/εCL ratio on the hydrophilicity (contact angle of wetting), hydrolytic stability, cytotoxicity, protein and cell adhesion, and cell proliferation using umbilical cord multipotent stem cells. It was found that the increase of EtOEP/εCL ratio results in increase of hydrophilicity of the polymer films with lowering of the protein and cell adhesion. MTT cytotoxicity test showed no significant deviations in toxicity of poly(εCL) and poly(εCL)-b-poly(EtOEP)-based films. The influence of the length of poly(EtOEP)chain in block-copolymers on fibrotic reactions was analyzed using subcutaneous implantation experiments (Wistar line rats), the increase of the width of the fibrous capsule correlated with higher EtOEP/εCL ratio. However, the copolymer-based film with highest content of polyphosphate had been subjected to faster degradation with a formation of developed contact surface of poly(εCL). The rate of the degradation of polyphosphate in vivo was significantly higher than the rate of the degradation of polyphosphate in vitro, which only confirms an objective value of in vivo experiments in the development of polymer materials for biomedical applications.

Rare-earth metal complexes derived from the acids Ph2C(X)CO2H (X= OH, NH2): Structural and ring opening polymerization (ROP) studies

Treatment of Ln(NO3)3.6H2O (Ln = La, Ce) with an equimolar amount of 2,2′-diphenylglycine (DpgH) in ethanol afforded the corresponding hexacoordinated complexes (DpgH±)3Ln(NO3)3.H2O (DpgH± = zwitterionic 2,2′-diphenylglycine, Ln = La (1), Ce (2)). The spectroscopic and structural features of these compounds have been investigated. Similar reactions with the related benzilic acid (BenzH2) were unsuccessful. The catalytic behaviour of 1 and 2 in the homo- and copolymerization of ε-caprolactone (ε-CL) and rac-lactide (r-LA) has been investigated herein. In the case of ε-CL, the two complexes exhibited comparable activity, allowing for complete monomer conversion under aerobic and solvent-free conditions at 150 °C in 24 h. With respect to the ROP of r-LA, 1 was found to be completely inactive, while only 8% conversion was achieved in the presence of 2. Liquid oligomers were isolated during ε-CL/r-LA co-polymerization in the presence of both complexes. The catalytic activity of the pre-ligands DpgH and BenzH2 (i.e. metal-free) was also examined. Interestingly, only BenzH2 was found to be active, although it required a higher catalyst loading and the presence of benzyl alcohol as co-activator.

Biocatalytic synthesis of poly[ε-caprolactone-co-(12-hydroxystearate)] copolymer for sorafenib nanoformulation useful in drug delivery

Nanoformulations can play an important role in the improvement of anticancer drug therapies. The bioavailability of sorafenib, which is the exclusively applied drug in the treatment of unresectable hepatocellular carcinoma, may be increased by its incorporation in a biocompatible nanoparticulate matrix that is capable of targeting and controlling the drug release. The copolymers of ε-caprolactone are emerging biodegradable compounds for drug delivery applications. In this work, an immobilized lipase and three native hydrolases, a lipase, an esterase and a protease (two of them not previously used as polyesterification catalysts) have been studied as biocatalysts for the synthesis of oligomers of ε-caprolactone and 12-hydroxystearic acid, proving different selectivity regarding the polymerization degree, ratio of linear and cyclic oligomers, and insertion of the fatty acid units in the polymeric chain. The synthesized poly[ε-caprolactone-co-(12-hydroxystearate)] was used as a novel encapsulating copolymer for preparation of sorafenib-loaded polymeric nanocomposites. The nanoparticle formulation by emulsion-solvent evaporation method was optimized for particle size and encapsulation efficiency. The developed nanotherapeutics showed promising drug release profile and cytotoxic effect in vitro in HepG2 hepatocellular cells.

Cellular attachment behavior on biodegradable polymer surface immobilizing endothelial cell-specific peptide

Small-caliber artificial blood vessels with inner diameters of smaller than 4 mm have not been put into practical use because of early thrombus formation and graft occlusion. To realize small-caliber artificial blood vessels with anti-thrombus property and long-term patency, one of the promising approaches is endothelialization of the lumen by tissue engineering approaches. Integrin α4β1 on the endothelial cell membrane is known to act as a receptor for Arg-Glu-Asp-Val (REDV) tetra-peptide, and this peptide can be used as a specific ligand to introduce endothelial cell attachment onto the surfaces of polymer scaffold. In this study, biodegradable polymer surface immobilizing REDV peptide were prepared, and the specific attachment of endothelial cells on it was investigated as a preliminary study for tissue-engineered small-caliber blood vessels in a future application. We synthesized copolymer of ε-caprolactone and depsipeptide having reactive carboxylic acid side-chain groups (PGDCL), and REDV peptide was attached to the copolymer to give PGDCL-REDV. The attachment of human umbilical vein endothelial cells (HUVECs) were investigated for the blend polymer film prepared by mixing PGDCL and PGDCL-REDV. The obtained blend polymer films exhibited sequence- and cell-specific HUVECs attachment through REDV peptide recognition. This technique should be useful not only to obtain artificial blood vessels which induce endothelialization and but also to provide biodegradable scaffolds with specific ligands immobilized surfaces for tissue regeneration.

π-π-Stacked Poly(ε-caprolactone)-b-poly(ethylene glycol) Micelles Loaded with a Photosensitizer for Photodynamic Therapy.

To improve the in vivo stability of poly(ε-caprolactone)-b-poly(ethylene glycol) (PCL-PEG)-based micelles and cargo retention by π-π stacking interactions, pendant aromatic rings were introduced by copolymerization of ε-caprolactone with benzyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate (TMC-Bz). It was shown that the incorporation of aromatic rings yielded smaller micelles (18–30 nm) with better colloidal stability in PBS than micelles without aromatic groups. The circulation time of i.v. injected micelles containing multiple pendant aromatic groups was longer (t½-α: ~0.7 h; t½-β: 2.9 h) than that of micelles with a single terminal aromatic group (t½ < 0.3 h). In addition, the in vitro partitioning of the encapsulated photosensitizer (meta-tetra(hydroxyphenyl)chlorin, mTHPC) between micelles and human plasma was favored towards micelles for those that contained the pendant aromatic groups. However, this was not sufficient to fully retain mTHPC in the micelles in vivo, as indicated by similar biodistribution patterns of micellar mTHPC compared to free mTHPC, and unequal biodistribution patterns of mTHPC and the host micelles. Our study points out that more detailed in vitro methods are necessary to more reliably predict in vivo outcomes. Furthermore, additional measures beyond π-π stacking are needed to stably incorporate mTHPC in micelles in order to benefit from the use of micelles as targeted delivery systems.

Copolymers of ε-caprolactone and ε-caprolactam via polyesterification: towards sequence-controlled poly(ester amide)s

Alternating copolymer of ε-caprolactone and ε-caprolactam is synthesized through polyesterification. This efficient and straightforward strategy holds promising future for the synthesis of sequence-controlled poly(ester amide)s.

Application of Diethylzinc/propyl Gallate Catalytic System for Ring-Opening Copolymerization of rac-Lactide and ε-Caprolactone.

Biodegradable polyesters gain significant attention because of their wide potential biomedical applications. The ring-opening polymerization method is widely used to obtain such polymers, due to high yields and advantageous properties of the obtained material. The preparation of new, effective, and bio-safe catalytic systems for the synthesis of biomedical polymers is one of the main directions of the research in modern medical chemistry. The new diethylzinc/propyl gallate catalytic system was first used in the copolymerization of ε-caprolactone and rac-lactide. In this paper, the activity of the new zinc-based catalytic system in the copolymerization of cyclic esters depending on the reaction conditions was described. The microstructure analysis of the obtained copolyesters and their toxicity studies were performed. Resulted copolyesters were characterized by low toxicity, moderate dispersity (1.19–1.71), varying randomness degree (0.18–0.83), and average molar mass (5300–9800 Da).

Poly(ε-caprolactone-co-p-dioxanone): a Degradable and Printable Copolymer for Pliable 3D Scaffolds Fabrication toward Adipose Tissue Regeneration

The advancement of 3D printing technologies in the fabrication of degradable scaffolds for tissue engineering includes, from the standpoint of the polymer chemists, an urgent need to develop new materials that can be used as ink and are suitable for medical applications. Here, we demonstrate that a copolymer of ε-caprolactone (CL) with low amounts of p-dioxanone (DX) (15 mol %) is a degradable and printable material that suits the requirements of melt extrusion 3D printing technologies, including negligible degradation during thermal processing. It is therefore a potential candidate for soft tissue regeneration. The semicrystalline CL/DX copolymer is processed at a lower temperature than a commercial polycaprolactone (PCL), shaped as a filament for melt extrusion 3D printing and as porous and pliable scaffolds with a gradient design. Scaffolds have Young's modulus in the range of 60-80 MPa, values suitable for provision of structural support for damaged soft tissue such as breast tissue. SEM and confocal microscope indicate that the CL/DX copolymer scaffolds support adipose stem cell attachment, spreading, and proliferation.

Biodegradable Oligoesters of ε-Caprolactone and 5-Hydroxymethyl-2-Furancarboxylic Acid Synthesized by Immobilized Lipases.

Following the latest developments, bio-based polyesters, obtained from renewable raw materials, mainly carbohydrates, can be competitive for the fossil-based equivalents in various industries. In particular, the furan containing monomers are valuable alternatives for the synthesis of various new biomaterials, applicable in food additive, pharmaceutical and medical field. The utilization of lipases as biocatalysts for the synthesis of such polymeric compounds can overcome the disadvantages of high temperatures and metal catalysts, used by the chemical route. In this work, the enzymatic synthesis of new copolymers of ε-caprolactone and 5-hydroxymethyl-2-furancarboxylic acid has been investigated, using commercially available immobilized lipases from Candida antarctica B. The reactions were carried out in solvent-less systems, at temperatures up to 80 °C. The structural analysis by MALDI TOF-MS, NMR, and FT-IR spectroscopy confirmed the formation of cyclic and linear oligoesters, with maximal polymerization degree of 24 and narrow molecular weight distribution (dispersity about 1.1). The operational stability of the biocatalyst was explored during several reuses, while thermal analysis (TG and DSC) indicated a lower thermal stability and higher melting point of the new products, compared to the poly(ε-caprolactone) homopolymer. The presence of the heterocyclic structure in the polymeric chain has promoted both the lipase-catalyzed degradation and the microbial degradation. Although, poly(ε-caprolactone) is a valuable biocompatible polymer with important therapeutic applications, some drawbacks such as low hydrophilicity, low melting point, and relatively slow biodegradability impeded its extensive utilization. In this regard the newly synthesized furan-based oligoesters could represent a “green” improvement route.

Enhancing the Properties of Poly(ε-caprolactone) by Simple and Effective Random Copolymerization of ε-Caprolactone with p-Dioxanone.

We have developed a straightforward strategy to obtain semicrystalline and random copolymers of ε-caprolactone (CL) and p-dioxanone (DX) with thermal stabilities similar to poly(ε-caprolactone), PCL, but with a faster hydrolytic degradation rate. CL/DX copolymers are promising inks when printing scaffolds aimed for tissue engineering. Such copolymers behave similar to PCL and resorb faster. The copolymers were synthesized by bulk ring-opening copolymerization, achieving a high yield; a molecular weight, Mn, of 57-176 kg mol-1; and an inherent viscosity of 1.7-1.9 dL g-1. The copolymer microstructure consisted of long CL blocks that are separated by isolated DX units. The block length and the melting point were a linear function of the DX content. The copolymers crystallize as an orthorhombic lattice that is typical for PCL, and they formed more elastic, softer, and less hydrophobic films with faster degradation rates than PCL. Relatively high thermal degradation temperatures (above 250 °C), similar to PCL, were estimated by thermogravimetric analysis, and copolymer filaments for three-dimensional printing and scaffolds were produced without thermal degradation.

Polyethylene-like macrolactone-based polyesters: Rheological, thermal and barrier properties

Linear aliphatic poly(ester)s are receiving increasing interest due to their properties comparable to that of common polyethylene. In this work, unsaturated macrolactone ω-6-hexadecenlactone (6HDL) is used for the preparation of long-methylene chain aliphatic polyesters by metal-catalyzed ring-opening polymerization (ROP). Block and random copolymer of ε-caprolactone (CL) are then synthetized. The microstructures of these polyesters are characterized by 1H and 13C NMR. Their rheological, thermal and barrier properties are evaluated and discussed. For comparison purposes, the properties of the relative homopolymers are also determined. Results show that the properties of these polymers differ depending on the main chain structure. In particular, the viscoelastic behavior of the copolymer sample shows an order-disorder transition in the temperature range of 75–85 °C. Thermogravimetric analysis and barrier properties show that the copolymers have a resistance to the diffusion of gases and vapors intermediate between that of the parent homopolymers.

De Novo Synthesis and Assembly of Flexible and Biocompatible Physical Sensing Platforms

AbstractFlexible physical sensing platforms (PSP) that can detect and communicate with surrounding physical data, such as force, strain, and temperature, are of interest in a variety of high‐tech fields, such as for wearable electronics, soft robotics, and real‐time healthcare monitoring. However, a crucial question remains relative to the design and assembly of PSPs that can meet the multitude of requirements for such devices, such as biocompatibility, stretchability, and high‐sensitivity to the target factor. In this study, a flexible PSP system based on graphene and biodegradable copolyester poly(CL‐co‐TOSUO) (PCT), which is synthesized by ring‐opening copolymerization of ε‐caprolactone (CL) and 1,4,8‐trioxaspiro‐[4,6]‐9‐undecanone (TOSUO). In this PSP system, graphene acts as conductive layer to connect the electrical signals, while the highly‐stretchable linear copolyester with structural transfer temperature (melting temperature of crystals) at 37 °C provides an active substrate to sense moderate mechanical and temperature stimuli. The resultant PCT/graphene PSP features high sensitivity for a manifold of mild surrounding physical stimuli, such as finger touch and movement, sound vibrations, body temperature, and light bulb temperature, showing promising applications in healthcare monitoring, human–machine interface, as well as soft robotics.