Polylactic acid caprolactone (PLCL) is a polymer material copolymerized by L-lactide and other monomers. Through copolymerization modification, PLCL can effectively control the melting point, transparency, toughness and heat resistance of polylactic acid, making up for the shortcomings of blending modification. Polylactic acid (PLA) has good biocompatibility and processing performance, but its slow degradation rate, brittleness and low mechanical strength limit the application of PLA. Polycaprolactone (PCL) has good biocompatibility, biodegradability and drug permeability, good toughness, processing and thermal shape memory properties, but PCL has low strength and poor hydrophilicity, which limits its scope of application. Through copolymerization modification, the introduction of CL segments into PLA can adjust the crystallinity, biodegradability and mechanical properties of the product, so that the material has good flexibility and elasticity, and can be widely used in biomaterials, 3D printing, degradable biological products and other fields.
Figure 1. Physical properties of PLCL,PLCL/Col, PLCL/MXene, and PLCL/Col/MXene nanofibrous matrices. (Lee SH,et al.; 2022)
PLCL is a white or light yellow tough rubber polymer. It is formed by ring-opening polymerization of polylactic acid and polycaprolactone. By changing the chain length ratio of polylactic acid and polycaprolactone, PLCL with different mechanical properties and degradation rates can be obtained. PLCL has good biocompatibility and can be completely degraded in the body. The final degradation products are H2O and CO2, and the intermediate product is lactic acid, which has no side effects on the body. PLCL has good mechanical properties and can be dissolved in solvents such as hexafluoroisopropanol. It has high spinnability and is mostly prepared into tissue engineering scaffolds such as bone tissue scaffolds, vascular scaffolds, and heart tissue scaffolds. PLCL fibers prepared by electrospinning have high porosity and specific surface area. Their ultrafine fiber nonwoven structure can mimic the extracellular matrix and is an ideal material for promoting the repair and regeneration of damaged parts in tissue engineering. However, PLCL fibers belong to polyesters and are hydrophobic synthetic fibers with poor hydrophilicity, which is not conducive to cell adhesion and proliferation, thus limiting their application in the medical field. At present, the academic community improves the hydrophilicity of PLCL fibers mainly by mixing PLCL with hydrophilic natural or synthetic polymer materials or post-treating PLCL ultrafine fiber nonwoven materials, thereby promoting cell adhesion and proliferation. PLCL will hydrolyze in TFA, reducing the number of hydrophobic ester groups and increasing the number of hydrophilic end groups, which is beneficial to improve the hydrophilicity of PLCL fiber materials and thus improve their biocompatibility. The commonly used solvent for PLCL electrospinning is HFIP. By adding TFA to the solvent and changing the ratio of HFIP to TFA, the surface wettability of PLCL nonwoven materials can be adjusted.
Application of PLCL in medical devices: 1. Medical sutures; PLCL has good biocompatibility and biodegradability and can be used as a medical device. For example, PLCL can be used as a medical suture. When used, the suture is stretched 200% and then moulded. After surgery, as the body temperature rises, the shape memory of the suture is restored and the wound is gradually tightened and closed. Advantages: it is temperature sensitive and has good shape memory function; it has good biocompatibility and is biodegradable. 2. 3D printed bone repair scaffolds; PLCL has the advantages of controllable degradation rate, high flexibility, adjustable elasticity and adjustable tensile strength, and can be used in bone tissue engineering scaffolds. 3. Drug carriers; Sustained release and controlled release of drugs are very important for the treatment of tumors. It controls the release of drugs so that the drugs can be released in a certain part of the human body for a long time and maintain a certain blood drug concentration for a certain period of time, thereby reducing the number of drug administrations and avoiding uneven uptake. PLCL has good mechanical strength, elasticity and flexibility, and can be prepared into drug-loaded nanofibres by electrospinning, which has good sustained release properties. 4. Microspheres; PLCL, as a copolymer of L-polylactic acid and polycaprolactone, balances the support performance and flexibility of the material, and can be prepared into microspheres for use in facial fillers, personal care cosmetics and other fields.
Alternate Names:
PLCL
Poly(L-lactide-co-ε-caprolactone)
Poly(L-lactide-co-caprolactone)
Poly(L-lactide-co-εCL)
Poly(L-lactide-co-ε-caprolactone)
Poly(L-lactic acid-co-caprolactone)
Poly(L-LA-co-CL)
References:
1. Lee SH, et al.; Ternary MXene-loaded PLCL/collagen nanofibrous scaffolds that promote spontaneous osteogenic differentiation. Nano Converg. 2022, 9(1):38.
2. Zhang M, et al.; Novel PLCL nanofibrous/keratin hydrogel bilayer wound dressing for skin wound repair. Colloids Surf B Biointerfaces. 2023, 222:113119.
Drug-loaded PLCL/PEO-SA bilayer nanofibrous membrane for controlled release
J Biomater Sci Polym Ed.
Authors: Huang Y, Wang L, Liu Y, Li T, Xin B.
Abstract
The bilayer nanofibrous membrane fabricated via electrospinning technique can be considered as an ideal structure for the treatment of chronic skin diseases and exudative wound dressings. Wound exudate would affect healing and increases the likelihood of infection at the same time. Therefore, it is essential to produce a kind of wound dressing with relatively high hygroscopicity which could absorb wound exudate and provide a relatively dry healing environment. Bilayer nanofibrous membranes of poly(L-lactide-co-ε-caprolactone)/tetracycline hydrochloride- polyethylene oxide/sodium alginate-zinc oxide (PLCL/TCH-PEO/SA-ZnO) with drug delivery potential were prepared by electrospinning for wound healing. Then, a cross-linking which involved soaking the samples in an aqueous solution containing strontium ions for 4 h was conducted. SEM images showed that membranes still maintained the peculiar nanofibrous structure. The spinning aid (PEO) used was removed in the cross-linked alginate without affecting the PLCL/TCH outer layer gave the membrane good mechanical properties and manageability. The hydrophilicity of the mats was tested to evaluate the ability of the bilayer membrane to absorb exudate from the wound. In vitro drug release suggested that antibacterial agents TCH could release continuously more than 10 days. The cross-linked fibrous membrane has improved mechanical properties and fluid repellency, thus representing a barrier to the external environment and effective wound protection. Consequently, the bilayer fibrous scaffold with good hygroscopicity and drug release properties would have wide applications prospects for the treatment of chronic skin diseases and exudative wound dressings.
PLCL-TPU bi-layered artificial blood vessel with compliance matching to host vessel
J Biomater Appl.
Authors: Guan L, Zhao H, Wang K, Zhang KQ, Meng K.
Abstract
Compliance mismatch between the artificial blood vessel and the host vessel leads to abnormal hemodynamics and is a major mechanical trigger of intimal hyperplasia. Efforts have been made to achieve higher compliance of artificial blood vessels. However, the preparation of artificial blood vessels with compliance matching to host vessels has not been realized. A bi-layered artificial blood vessel was successfully prepared by dip-coating and electrospinning composite method using poly(L-Lactide-co-caprolactone) (PLCL) and thermoplastic poly(ether urethane) (TPU). In the case of a certain wall thickness (200 μm), thickness ratios of the PLCL inner layer (dip-coating method) and TPU outer layer (electrospinning method) were controlled at 0:1, 1:9, 3:7, 5:5, 7:3, and 1:0 respectively and the compliance, radial tensile properties, burst pressure, and suture retention strength were investigated. Results showed compliance value of the artificial blood vessel decreased with the increase of the thickness ratio, which suggested the compliance of the bi-layered artificial blood vessel can be regulated by adjusting the ratio of the inner and outer layer thicknesses. In the six different artificial blood vessels, the one with thickness ratio of 1:9 not only had high compliance (8.768 ± 0.393%/100 mmHg) but also can guarantee the other mechanical properties, such as the radial breaking strength (6.333 ± 0.689 N/mm), burst pressure (534.473 ± 20.899 mmHg), and suture retention strength (300.773 ± 9.351 cN). The proposed artificial blood vessel preparation method is expected to achieve compliance matching with the host vessel. It is beneficial for eliminating abnormal hemodynamics and reducing intimal hyperplasia.
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