Skip to main content

Synthetic Polymer Scaffolds

Synthetic polymer scaffolds are engineered structures intended to support cells and tissue repair.[1][2] Biodegradable designs aim to lose material as tissue develops.[1][2]

Materials​

  • Polylactide (PLA), including PLLA formulations. A polyester family; its behavior depends on stereochemistry, molecular weight, processing and construct geometry. There is no single degradation time that applies to every PLA scaffold.
  • Polyglycolide (PGA) and poly(lactide-co-glycolide) (PLGA). Biodegradable polyesters with properties that vary by formulation and architecture.
  • Polycaprolactone (PCL). Used in flexible, relatively slowly degrading constructs; performance still depends on the specific design.
  • Polybutylene succinate (PBSu) and PLA/PBSu blends. Investigated to adjust flexibility and cell compatibility.[1][2]

What the existing laboratory evidence shows​

Sartoneva and colleagues studied human urothelial cells and adipose stromal cells on PLA/PBSu discs in vitro.[1] Urothelial cells remained viable and proliferated on all four PLA/PBSu formulations, whereas adipose stromal cells proliferated on PBSu-containing discs but formed aggregates rather than attaching to pure PLA; phenotype-marker staining also supported further investigation of PBSu-containing materials.[1]

Oberpenning, Atala and colleagues (1999) grew urothelial and smooth-muscle cells from canine bladder biopsies, seeded them onto preformed bladder-shaped polymer scaffolds, and replaced the excised native bladder with the resulting neo-organ. Over up to 11 months, the neo-bladders retained urine with normal capacity, elastic properties and histologic architecture. This canine subtotal-cystectomy model used healthy donor tissue.[5] In a separate phase II study of a different autologous cell-seeded biodegradable bladder scaffold, 10 implanted children and adolescents with spina bifida had no clinically or statistically significant improvement in capacity or compliance at 12 or 36 months; bowel obstruction and/or bladder rupture occurred in 4/10.[6]

Design and evaluation​

A urinary scaffold needs appropriate compliance and strength, reliable handling and suture retention, a suitable tissue interface and acceptable degradation products. Porosity may help cell and vessel ingrowth but must be reconciled with the need to contain urine. Surface attachment of cells is only an early step.[2][3]

Evaluation includes vascular integration, urine leakage, fibrosis or contraction, infection, encrustation and function over time.[3] A 2024 systematic review of 48 preclinical urethral studies in male animals (2015–2022) found stricture formation in both rabbit studies of purely synthetic PLA-containing patches: 5 of 6 animals were stricture-free with PLA/PLG/PLC for a 20-mm defect at 24 weeks and with PLA for a 15-mm defect at 12 weeks. The review concluded that natural polymers, alone or combined with synthetic materials, gave better postoperative outcomes in animals than purely synthetic constructs.[7]

Clinical status​

Synthetic scaffolds for regenerative urinary-organ replacement remain a developing field. In an observational series of five boys aged 10–14 years with complex posterior urethral defects, tubularized polyglycolic acid:poly(lactide-co-glycolide) scaffolds seeded with autologous bladder muscle and epithelial cells were implanted; at a median of 71 months (range 36–76) all urethras remained patent (median maximum flow 27.1 mL/s), one patient needed transurethral incision of an anastomotic narrowing at 4 weeks, and one needed a pubovesical sling for stress incontinence.[8] For the related but distinct category of autologous tissue-engineered oral-mucosa grafts, the 2026 EAU guideline gives a strong recommendation against use outside a clinical trial.[2][4]

References​

1. Sartoneva R, Lyyra I, Juusela M, et al. In Vitro Biocompatibility of Polylactide and Polybutylene Succinate Blends for Urethral Tissue Engineering. Journal of Biomedical Materials Research. Part B, Applied Biomaterials. 2023;111(10):1728–1740. doi:10.1002/jbm.b.35268

2. Keshel SH, Rahimi A, Hancox Z, et al. The Promise of Regenerative Medicine in the Treatment of Urogenital Disorders. Journal of Biomedical Materials Research. Part A. 2020;108(8):1747–1759. doi:10.1002/jbm.a.36942

3. Duan L, Wang Z, Fan S, Wang C, Zhang Y. Research progress of biomaterials and innovative technologies in urinary tissue engineering. Frontiers in Bioengineering and Biotechnology. 2023;11:1258666. doi:10.3389/fbioe.2023.1258666.

4. European Association of Urology. EAU Guidelines on Urethral Strictures. 2026. Chapter 9: Tissue transfer. Guideline text and recommendations.

5. Oberpenning F, Meng J, Yoo JJ, Atala A. De novo reconstitution of a functional mammalian urinary bladder by tissue engineering. Nat Biotechnol. 1999;17(2):149-155. doi:10.1038/6146

6. Joseph DB, Borer JG, De Filippo RE, Hodges SJ, McLorie GA. "Autologous cell seeded biodegradable scaffold for augmentation cystoplasty: phase II study in children and adolescents with spina bifida." J Urol. 2014;191(5):1389–1395. doi:10.1016/j.juro.2013.10.103

7. Chepelova N, Sagitova G, Munblit D, et al. "The search for an optimal tissue-engineered urethra model for clinical application based on preclinical trials in male animals: a systematic review and meta-analysis." Bioeng Transl Med. 2024;9(6):e10700. doi:10.1002/btm2.10700

8. Raya-Rivera A, Esquiliano DR, Yoo JJ, Lopez-Bayghen E, Soker S, Atala A. "Tissue-engineered autologous urethras for patients who need reconstruction: an observational study." Lancet. 2011;377(9772):1175-1182. doi:10.1016/S0140-6736(10)62354-9

See also: Decellularized ECM, Composite Scaffolds.