Additive manufacturing of biodegradable magnesium implants and scaffolds: Review of the recent advances and research trends

Synthetic grafting needs improvements to eliminate secondary surgeries for the removal of implants after healing of the defected tissues.Tissue scaffolds are engineered to serve as temporary templates,which support the affected tissue and gradually degrade through the healing period.Beside mechanical function to withstand the anatomic loading conditions,scaffolds should also provide a decent biological function for the diffusion of nutrients and oxygen to the cells,and excretion of the wastes from the cells to promote the new tissue growth and vascularization.Moreover,the degradation byproducts of the scaffolds should be safe to the human body.Development of such multifunctional scaffolds requires selection of the right material,design,and manufacturing method.Mg has been recognized as the prominent biodegradable metal with regards to its mechanical properties matching to that of human bone,degradability in the body fluid,and its ability to stimulate new tissue growth.Scaffolds with intricate porous structures can be designed according to the patient-specific anatomic data using computer aided designs.Additive manufacturing(AM)is the right method to materialize these models rapidly with reasonably acceptable range of dimensional accuracy.Thus,the recent research trend is to develop ideal scaffolds using biodegradable Mg through AM methods.This review compiles and discusses the available literature on the AM of biodegradable Mg parts from the viewpoints of material compositions,process conditions,formation quality,dimensional accuracy,microstructure,biodegradation,and mechanical properties.The current achievements are summarized together,and future research directions are identified to promote clinical applications of biodegradable Mg through the advancement of AM.

Morphological properties and proliferation analysis of olfactory ensheathing cells seeded onto three-dimensional collagen-heparan sulfate biological scaffolds

This study aimed to examine the differences in the morphological properties and proliferation of olfactory ensheathing cells in three-dimensional culture on collagen-heparan sulfate biological scaffolds and in two-dimensional culture on common flat culture plates. The proliferation rate of olfactory ensheathing cells in three-dimensional culture was higher than that in two-dimensional culture, as detected by an M-I-r assay. In addition, more than half of the olfactory ensheathing cells subcultured using the trypsinization method in three-dimensional culture displayed a spindly Schwann cell-like morphology with extremely long processes, while they showed a flat astrocyte-like morphology in two-dimensional culture. Moreover, spindle-shaped olfactory ensheathing cells tended to adopt an elongated bipolar morphology under both culture conditions. Experimental findings indicate that the morphological properties and proliferation of olfactory ensheathing cells in three-dimensional culture on collagen-heparan sulfate biological scaffolds are better than those in two-dimensional culture.

Magnetic resonance imaging-three-dimensional printing technology fabricates customized scaffolds for brain tissue engineering

Conventional fabrication methods lack the ability to control both macro- and micro-structures of generated scaffolds. Three-dimensional printing is a solid free-form fabrication method that provides novel ways to create customized scaffolds with high precision and accuracy. In this study, an electrically controlled cortical impactor was used to induce randomized brain tissue defects. The overall shape of scaffolds was designed using rat-specific anatomical data obtained from magnetic resonance imaging, and the internal structure was created by computer- aided design. As the result of limitations arising from insufficient resolution of the manufacturing process, we magnified the size of the cavity model prototype five-fold to successfully fabricate customized collagen-chitosan scaffolds using three-dimensional printing. Results demonstrated that scaffolds have three-dimensional porous structures, high porosity, highly specific surface areas, pore connectivity and good internal characteristics. Neural stem cells co-cultured with scaffolds showed good viability, indicating good biocompatibility and biodegradability. This technique may be a promising new strategy for regenerating complex damaged brain tissues, and helps pave the way toward personalized medicine.

Morphological Evaluation of PLA/Soybean Oil Epoxidized Acrylate Three-Dimensional Scaffold in Bone Tissue Engineering

Tissue engineering’s main goal is to regenerate or replace tissues or organs that have been destroyed by disease,injury,or congenital disabilities.Tissue engineering now uses artificial supporting structures called scaffolds to restore damaged tissues and organs.These are utilized to attach the right cells and then grow them.Rapid prototyping appears to be the most promising technology due to its high level of precision and control.Bone tissue replacement“scaffolding”is a common theme discussed in this article.The fused deposition technique was used to construct our scaffold,and a polymer called polylactic acids and soybean oil resin were used to construct our samples.The samples were then divided into two groups;the first group was left without immersion in the simulated body fluid and served as a control for comparison.The second group was immersed in the simulated body fluid.The results of the Field Emission Scanning Electron Microscope(FESEM),Energy Dispersive X-ray Spectroscopy(EDX)and X-ray diffraction(XRD)were utilized to interpret the surface attachment to ions,elements,and compounds,giving us a new perspective on scaffold architecture.In this study,an innovative method has been used to print therapeutic scaffold that combines fused deposition three-dimensional printing with ultraviolet curing to create a high-quality biodegradable polymeric scaffold.Finally,the results demonstrate that adding soybean oil resin to the PLA increased ion attachment to the surface while also attracting tricalcium phosphate formation on the surface of the scaffold,which is highly promising in bone tissue replacement.In conclusion,the soybean oil resin,which is new in the field of bone tissue engineering,shows magnificent characteristics and is a good replacement biopolymer that replaces many ceramic and polymeric materials used in this field that have poor morphological characteristics.

Challenges and Solutions for the Additive Manufacturing of H) Biodegradable Magnesium Implants

Due to their capability of fabricating geometrically complex structures,additive manufacturing(AM)techniques have provided unprecedented opportunities to produce biodegradable metallic implants—especially using Mg alloys,which exhibit appropriate mechanical properties and outstanding biocompatibility.However,many challenges hinder the fabrication of AM-processed biodegradable Mg-based implants,such as the difficulty of Mg powder preparation,powder splash,and crack formation during the AM process.In the present work,the challenges of AM-processed Mg components are analyzed and solutions to these challenges are proposed.A novel Mg-based alloy(Mg-Nd-Zn-Zr alloy,JDBM)powder with a smooth surface and good roundness was first synthesized successfully,and the AM parameters for Mg-based alloys were optimized.Based on the optimized parameters,porous JDBM scaffolds with three different architectures(biomimetic,diamond,and gyroid)were then fabricated by selective laser melting(SLM),and their mechanical properties and degradation behavior were evaluated.Finally,the gyroid scaffolds with the best performance were selected for dicalcium phosphate dihydrate(DCPD)coating treatment,which greatly suppressed the degradation rate and increased the cytocompatibility,indicating a promising prospect for clinical application as bone tissue engineering scaffolds.

In vitro biodegradability and biocompatibility of porous Mg-Zn scaffolds coated with nano hydroxyapatite via pulse electrodeposition

The biodegradability and biocompatibility of porous Mg-2Zn（mass fraction, %） scaffolds coated with nano hydroxyapatite（HAP） were investigated. The nano HAP coating on Mg-2Zn scaffolds was prepared by the pulse electrodeposition method. The as-deposited scaffolds were then post-treated with alkaline solution to improve the biodegradation behavior and biocompatibility for implant applications. The microstructure and composition of scaffold and nano HAP coating, as well as their degradation and cytotoxicity behavior in simulated body fluid（SBF） were investigated. The post-treated coating is composed of needle-like HAP with the diameter less than 100 nm developed almost perpendicularly to the substrate, which exhibits a similar composition to natural bone. It is found that the products of immersion in SBF are identified to be HAP,（Ca,Mg）3（PO4）2 and Mg（OH）2. The bioactivity, biocompatibility and cell viabilities for the as-coated and post-treated scaffold extracts are higher than those for the uncoated scaffold. MG63 cells are found to adhere and proliferate on the surface of the as-coated and post-treated scaffolds, making it a promising choice for medical application. The results show that the pulse electrodeposition of nano HAP coating and alkaline treatment is a useful approach to improve the biodegradability and bioactivity of porous Mg-Zn scaffolds.

Three-dimensionally Perforated Calcium Phosphate Ceramics

Porous calcium phosphate ceramics were produced by compression molding using a special mold followed by sintering. The porous calcium phosphate ceramics have three-dimensional and penetrated open pores 380-400μm in diacneter spaced at intervals of 200μm. The layers of the linear penetration pores alternately lay perpendicular to pore direction. The porosity was 59%-65% . The Ca/ P molar ratios of the porous calcium phos phate ceramics range from 1.5 to 1.85. A binder cantaining methyl cellulose was most effective for preparing the powder compact among vinyl acetate, polyvinyl alcohol, starch, stearic acid, methyl cellulose and their mixtures . Stainless steel, polystyrene, nylon and bamboo were used as the long columnar dies for the penetrated open pores. When polystyrene, nylon and bamboo were used as the long columnar male dies, the dies were burned oat during the sintering process. Using stainless steel as the male dies with the removal of the dies before heat treatment resulted in a higher level of densification of the calcium phosphate ceramic.

Hydrogel-supported poly(L-lactic acid) and polystyrene microsphere-based three-dimensional culture systems for in vitro cell expansion

The in vitro expansion of stem cells is important for their application in different life science fields such as cellular tissue and organ repair.An objective of this paper was to achieve static cell culture in vitro through peptide hydrogel-supported microspheres(MSs).The peptides,with their gel-forming properties,microstructures,and mechanical strengths characterized,were found to have good support for the MSs and to be injectable.The internal structures of poly(L-lactic acid)microspheres(PLLA-MSs)and polystyrene microspheres(PS-MSs)made in thelaboratory were observed and statistically analyzed in terms of particle size and pore size,following which the co-cultured MSs with cells were found to have good cell adhesion.In addition,three-dimensional(3D)culturing of cells was performed on the peptide and microcarrier composite scaffolds to measure cell viability and cell proliferation.The results showed that the peptides could be stimulated by the culture medium to self-assembly form a 3D fiber network structure.Under the peptide-Ms composite scaffold-based cell culture system,further enhancement of the cell culture effect was measured.The peptide-Ms composite scaffolds have great potential for the application in 3D cell culture and in vitro cellexpansion.

A drug-loaded composite coating to improve osteogenic and antibacterial properties of Zn-1Mg porous scaffolds as biodegradable bone implants

Zinc(Zn)alloy porous scaffolds produced by additive manufacturing own customizable structures and biodegradable functions,having a great application potential for repairing bone defect.In this work,a hydroxyapatite(HA)/polydopamine(PDA)composite coating was constructed on the surface of Zn-1Mg porous scaffolds fabricated by laser powder bed fusion,and was loaded with a bioactive factor BMP2 and an antibacterial drug vancomycin.The microstructure,degradation behavior,biocompatibility,antibacterial performance and osteogenic activities were systematically investigated.Compared with as-built Zn-1Mg scaffolds,the rapid increase of Zn2+,which resulted to the deteriorated cell viability and osteogenic differentiation,was inhibited due to the physical barrier of the composite coating.In vitro cellular and bacterial assay indicated that the loaded BMP2 and vancomycin considerably enhanced the cytocompatibility and antibacterial performance.Significantly improved osteogenic and antibacterial functions were also observed according to in vivo implantation in the lateral femoral condyle of rats.The design,influence and mechanism of the composite coating were discussed accordingly.It was concluded that the additively manufactured Zn-1Mg porous scaffolds together with the composite coating could modulate biodegradable performance and contribute to effective promotion of bone recovery and antibacterial function.

Biodegradable porous Zn-1Mg-3βTCP scaffold for bone defect repair:In vitro and in vivo evaluation

Zn-based materials are promising as bone repair materials,but their poor mechanical property and bioactivity as well as low degradation rate render the potential application.Rational structural and material design can address the concerns.In this study,porous Zn-1 wt.%Mg-3 vol.%β-TCP scaffolds with 40%and 60%preset porosities were fabricated via heating-press sintering using NaCl particles as space holders,and their mechanical properties,in vitro degradation behavior,cytotoxicity and in vivo osteogenic activities were evaluated.The results showed that the actual porosities of the scaffolds were 22%and 50%.Mg exists in the form of Zn 2 Mg and Zn 11 Mg 2,whileβ-TCP evenly distributed in the matrix.The compressive yield strength of scaffolds ranges from approximately 58.46 to 71.04 MPa,which is close to that of cancellous bone.The in vitro degradation tests showed that the corrosion rate of the scaffolds was in the range of about 2.73-4.28 mm y^(-1).Moreover,the scaffolds not only provided great space for osteoblasts adhesion and proliferation in vitro but also possessed favorable degradability and osteogenic activity in vivo.The porous Zn-1 wt.%Mg-3 vol.%β-TCP scaffolds manifest reliable mechanical properties,desirable degradability,and osteogenic activity,which are promising as next-generation bone repair materials.

Design and criteria of electrospun fibrous scaffolds for the treatment of spinal cord injury

The complex pathophysiology of spinal cord injury may explain the current lack of an effective therapeutic approach for the regeneration of damaged neuronal cells and the recovery of motor functions. Many efforts have been performed to design and develop suitable scaffolds for spinal cord regeneration, keeping in mind that the reconstruction of a pro-regenerative environment is the key challenge for an effective neurogenesis. The aim of this review is to outline the main features of an ideal scaffold, based on biomaterials, produced by the electrospinning technique and intended for the spinal cord regeneration. An overview of the poly- mers more investigated in the production of neural fibrous scaffolds is also provided.

Fabrication and Characterization of Poly Lactic Acid Scaffolds by Fused Deposition Modeling for Bone Tissue Engineering

Three-dimensional porous poly-lactic acid(PLA) scaffold was fabricated using fused deposition modeling(FDM) method including 30%, 50% and 70% nominal porosity. Study of phases in initial polymeric material and printed scaffolds was done by X-ray diffraction(XRD), and no significant phase difference was observed due to the manufacturing process, and the poly-lactic acid retains its crystalline properties. The results of the mechanical properties evaluation by the compression test show that the mechanical properties of the scaffold have decreased significantly with increasing the porosity of scaffold. The microstructure of scaffolds were studied by scanning electron microscope(SEM), showing that the pores had a regular arrangement and their morphology changed with porosity change. The mechanical properties of the poly-lactic acid scaffolds printed using fused deposition modeling, can be adapted to the surrounding tissue, by porosity change.

Extrusion-based additive manufacturing of Mg-Zn alloy scaffolds

Porous biodegradable Mg and its alloys are considered to have a great potential to serve as ideal bone substitutes.The recent progress in additive manufacturing(AM) has prompted its application to fabricate Mg scaffolds with geometrically ordered porous structures.Extrusionbased AM,followed by debinding and sintering,has been recently demonstrated as a powerful approach to fabricating such Mg scaffolds,which can avoid some crucial problems encountered when applying powder bed fusion AM techniques.However,such pure Mg scaffolds exhibit a too high rate of in vitro biodegradation.In the present research,alloying through a pre-alloyed Mg-Zn powder was ultilized to enhance the corrosion resistance and mechanical properties of AM geometrically ordered Mg-Zn scaffolds simultaneously.The in vitro biodegradation behavior,mechanical properties,and electrochemical response of the fabricated Mg-Zn scaffolds were evaluated.Moreover,the response of preosteoblasts to these scaffolds was systematically evaluated and compared with their response to pure Mg scaffolds.The Mg-Zn scaffolds with a porosity of 50.3% and strut density of 93.1% were composed of the Mg matrix and MgZn2second phase particles.The in vitro biodegradation rate of the Mg-Zn scaffolds decreased by 81% at day 1,as compared to pure Mg scaffolds.Over 28 days of static immersion in modified simulated body fluid,the corrosion rate of the Mg-Zn scaffolds decreased from 2.3± 0.9 mm/y to 0.7±0.1 mm/y.The yield strength and Young’s modulus of the Mg-Zn scaffolds were about 3 times as high as those of pure Mg scaffolds and remained within the range of those of trabecular bone throughout the biodegradation tests.Indirect culture of MC3T3-E1 preosteoblasts in Mg-Zn extracts indicated favorable cytocompatibility.In direct cell culture,some cells could spread and form filopodia on the surface of the Mg-Zn scaffolds.Overall,this study demonstrates the great potential of the extrusion-based AM Mg-Zn scaffolds to be further developed as biodegradable bone-substituting biomaterials.

Fabrication and performance of Zinc-based biodegradable metals: From conventional processes to laser powder bed fusion

Zinc (Zn)-based biodegradable metals (BMs) fabricated through conventional manufacturing methods exhibit adequate mechanical strength, moderate degradation behavior, acceptable biocompatibility, and bioactive functions. Consequently, they are recognized as a new generation of bioactive metals and show promise in several applications. However, conventional manufacturing processes face formidable limitations for the fabrication of customized implants, such as porous scaffolds for tissue engineering, which are future direction towards precise medicine. As a metal additive manufacturing technology, laser powder bed fusion (L-PBF) has the advantages of design freedom and formation precision by using fine powder particles to reliably fabricate metallic implants with customized structures according to patient-specific needs. The combination of Zn-based BMs and L-PBF has become a prominent research focus in the fields of biomaterials as well as biofabrication. Substantial progresses have been made in this interdisciplinary field recently. This work reviewed the current research status of Zn-based BMs manufactured by L-PBF, covering critical issues including powder particles, structure design, processing optimization, chemical compositions, surface modification, microstructure, mechanical properties, degradation behaviors, biocompatibility, and bioactive functions, and meanwhile clarified the influence mechanism of powder particle composition, structure design, and surface modification on the biodegradable performance of L-PBF Zn-based BM implants. Eventually, it was closed with the future perspectives of L-PBF of Zn-based BMs, putting forward based on state-of-the-art development and practical clinical needs.

Fabrication of Porous Scaffolds Using NaHCO_3 Particulates as the Porogen Material

A new method of fabricating porous polymer scaffolds was developed, using sodium hydrogen carbonate particulates as the porogen to foam. The pore structure of polymer scaffolds can easily be manipulated by controlling the size and weight fraction of sodium hydrogen carbonate particulates. The scaffolds are highly porous with a porosity greater than 90% and with a larger pore size ranging from 100-400μm, and are well distributed with the interconnected and open pore wall structure which is necessary for tissue engineering. We investigated the effect of the porosity of scaffolds, the pore size of scaffolds and material of polymer on the mechanical properties of scaffolds. The scaffolds fabricated by the method have more big pores than those by the convenient method of salt leaching.

可降解生物医用多孔Zn基支架研究进展

目前,治疗创伤、先天畸形、肿瘤组织切除等原因造成的大段骨缺损仍是骨科手术面临的主要挑战。利用骨组织工程支架代替自体骨移植在缺损部位进行骨重建为解决该问题带来新的方案。鉴于理想骨组织工程支架应具备良好生物相容性、适宜生物降解性、与骨组织相匹配的力学性能以及抗菌性等特征,多孔Zn基支架可能成为理想骨组织工程支架的最佳候选者。然而,近些年的研究发现目前开发的多孔Zn基支架存在力学性能差、体外浸泡及植入体内初期降解速率相对较快导致过量Zn 2+释放、高浓度Zn 2+能够抑菌杀菌但也会使Zn基支架细胞毒性增强进而导致支架植入体内后出现骨整合延迟等问题。鉴于此,近些年关于多孔Zn基支架的研究主要聚焦于改善支架力学性能、调控支架降解速率,同时赋予支架抑菌杀菌性能和良好生物相容性等方面。研究者们主要采取了对多孔Zn支架进行合金化处理、控制孔隙率、控制孔隙形貌和尺寸等手段来提高多孔Zn基支架的力学性能,同时实现对多孔Zn基支架降解速率的调控。此外,也有研究者利用电偶腐蚀原理调控多孔支架的降解速率。由于多孔Zn基支架降解过程中释放的Zn 2+严重影响支架的抑菌杀菌性能和生物相容性,且抑菌杀菌性能和良好生物相容性对Zn 2+浓度需求恰好相反,故目前对于同时赋予支架抑菌杀菌性能和良好生物相容性的有效手段仍在探索研究中。本文归纳了可降解多孔Zn基骨组织工程支架在制备方法、力学性能、生物降解性能、抑菌杀菌性能和生物相容性等方面的研究进展,分析了多孔Zn基骨组织工程支架面临的问题并展望了其前景,以期为制备力学性能优异、降解速率适宜可控并同时具备抑菌杀菌性能和良好生物相容性的多孔Zn基骨组织工程支架提供参考。

Fabrication of a Mood vessel scaffold with a combined polymer for tissue enginerring

Objective To investigate the possibility to fabricate a blood vessel scaffold with a combined polymer for tissue engineering. Methods A blood vessel scaffold was designed with a combined polymer composed of rabbit vascular smooth muscle cells ( VSMCs), collagen and a non-spinning fabric mesh of polyglycolic acid(PGA). VSMQ were implanted into collagen gel and their growth was observed. The mixed solution of VSMQ and collagen was dropped into the tubular scaffold, followed by 7-day culturing. Results VSMQ formed many prominences after culturing in gelatinous collagen for 3 - 4 hours. With cells extending, some cells became shuttle-or spindle-shaped. After VSMQ-collagen complex was implanted into the PGA mesh, most of VSMCs remained in the pore of PGA mesh with the formation of gelation. VSMCs could adhere to and grow on the PGA fiber. Conclusion The non-spinning PGA porous biodegradable material coated with collagen is a good carrier for VSMCs to adhere and grow. 5 refs,3 figs.

载Apelin-13缓释微囊的新型生物支架促兔输卵管再通的初步研究

目的:输卵管炎性不孕症严重危害女性自然生育功能,临床迫切需求的真正意义上的输卵管再通包括病变输卵管解剖和功能的修复两方面,目前尚无有效的治疗方案。本研究旨在从这两方面探讨促进输卵管修复再通的方法。方法:制备Apelin-13缓释微囊和聚乳酸-羟基乙酸共聚物[poly(lactic-co-glycolic acid),PLGA]三维生物支架,检测生物支架的基本特性及体内降解情况(质量损失率),微囊的体外释药(累积释药率)、体内释药(Apelin-13血药浓度)及体外降解(降解率)情况。将Apelin-13微囊(微囊组)/载Apelin-13缓释微囊的PLGA三维生物支架(支架微囊组)注入/置入慢性输卵管炎新西兰兔模型的输卵管,观察和比较对照组、模型组、微囊组和支架微囊组术后输卵管的通畅情况、镜下结构、雌激素受体和孕激素受体的阳性表达情况。结果:术后第4周时PLGA三维生物支架的质量损失率为98.66%,微囊的体外降解率为70.58%,Apelin-13缓释微囊30 d体外累计释药率达98.68%,Apelin-13血药浓度在5 d内达到峰值,并在25 d内保持稳定。与模型组和微囊组相比,支架微囊组术后输卵管管腔内炎症反应轻,输卵管通畅率高,雌激素受体和孕激素受体的表达水平高(均P<0.05),支架微囊组的各项指标接近对照组。结论:载Apelin-13缓释微囊的PLGA三维生物支架可全面修复输卵管的解剖结构和生理功能,有望真正有效实现炎性输卵管再通。

碳纳米管在组织工程修复中的作用与优势

背景:近来年,碳纳米管材料因其独特的结构及材料特性而备受关注,将其作为组织工程材料在组织修复中的研究逐渐深入,在动物体内已取得良好的修复效果。目的:综述碳纳米管作为组织工程材料的特性及碳纳米管用于组织工程修复中的研究进展。方法:应用计算机检索万方医学网、中国知网、维普、Web of Science和PubMed数据库中的相关文献,中文检索词为“碳纳米管、复合材料、组织工程、组织修复”,英文检索词为“carbon nanotubes,composite materials,tissue engineering,tissue repair”,最终纳入75篇文献进行归纳总结。结果与结论:①碳纳米管主要分为由单层管状石墨烯形成的单壁碳纳米管和由多个同心管状石墨烯层组成的多壁碳纳米管,通过修饰改性碳纳米管以及调节浓度使含有碳纳米管的复合支架材料获得更好导电性、机械性能、生物相容性及生物降解性。②通过促进蛋白质吸附、调控电信号转导通路及机械转导信号通路可以促进细胞增殖、分化、黏附等行为及提高细胞活性,从而促进骨重塑及整合、改善神经及心肌功能、加速缺损修复促进组织再生,且在体内无不良反应。③目前的研究表明碳纳米管复合材料能够完全修复临界大块骨缺损,达到自体移植相似的神经修复效果及使得受损心肌的生理心肌传导速度完全恢复。因此,碳纳米管作为新型生物材料在组织工程修复领域中具有巨大的潜力。④碳纳米管在组织修复领域的相关研究尚处于体外实验或动物实验水平,基于碳纳米管的复合材料要从实验研究走向临床实践还需要克服很多困难,如碳纳米管的毒理学评价、有效性评价等需后续研究进一步完善,而碳纳米管的直径、长度、纯度及复合材料的制备方法等参数与组织修复相关通路的联系需要进一步研究。

可生物降解的聚氨酯体内应用进展

聚氨酯由于其特殊的结构与性能,已被广泛应用于建筑、汽车、家居、医药等日常生活的诸多领域。因具有良好的生物相容性,聚氨酯材料在医药领域也极具应用前景。此外,通过对聚氨酯的分子结构进行设计,可以赋予其广泛的性能,如生物相容性、抗凝血特性、抗菌性能等。具有了这些特性的聚氨酯材料在组织工程、药物缓释等生物医药领域中被广泛应用。该文主要探讨了可生物降解聚氨酯在骨组织工程领域、血管组织工程领域、神经支架、药物缓释、人造皮肤和手术缝合线等医学方面的应用,并总结分析了其研究中存在的关键问题,展望了其未来的发展方向。