Table 2 Overview of scaffold grafts in urethral reconstruction

Core-shell structure scaffolds

Collagen/P(LLA-CL)

rabbit

2 cm

3 months

In vivo

wide caliber;

less collagen;

more smooth muscle;

thicker epithelium

[58]

Collagen/P(LLA-CL)

dog

2 cm

12 weeks

In vivo

abundant ECM;

better plasticity and strength;

Inhibit fibrin deposition

[59]

Single-layer scaffolds

BAM

rabbit

2 cm

6months

In vivo

multiple layers of continuous urethral epithelium;

upregulated the expression of myosin

[61]

BAM

canine

6 cm

12months

In vivo

continuous muscle layers and epithelial layers;

wide caliber

[62]

Porcine urethras

NA

NA

14days

In vitro

Imitate the microstructure and composition of natural tissues

[63]

BC

Rabbit

2 cm

3months

In vivo

Improve cell biological activity;

Low immunogenicity

[66]

BC/BAM

Rabbit

1 cm

3months

In vivo

Accelerate angiogenesis;

Wide caliber;

Multiple layers of continuous urethral epithelium

[67]

SF

Canine

5 cm

6months

In vivo

Complete epidermal layer and fibrolblast layer structure

[70]

hdCGTs

rabbit

2 cm

3months

In vivo

Wide caliber;

Improve graft stability;

Low immunogenicity

[72]

CCC

Minipig

2 cm

24 weeks

In vivo

Multiple layers of continuous urethral epithelium;

Low immunogenicity;

Outstanding stability and storability

[74]

cPUU

rabbit

1.5 cm

3 months

In vivo

High mechanical strength;

Wide caliber;

Reduced complication rate

[75]

Human amniotic

canine

3 cm

8 weeks

In vivo

Promote angiogenesis;

Multiple layers of continuous urethral epithelium;

Less scar tissue

[78]

AM

rabbit

1 cm

3months

In vivo

Simplify surgery procedure;

Reduce postoperative complications;

Good biocompatibility and low immunogenicity

[80]

AM

rabbit

2 cm

1months

In vivo

Low immunogenicity;

High blood vessel density

[92]

Bilayer composite scaffolds

Epithelial-muscular

Canine

1 cm

3months

In vivo

Effectively mimick native structure of urethra

[82]

BSM-

Autologous urethral tissue

Rabbit

2 cm

12 weeks

In vivo

Avoid cell expansion procedures;

Excellent processability;

Nonimmunogenicity

[83]

SF-SF

Rabbit

2 cm

3months

In vivo

High porosity;

Help smooth muscle and epithelial tissue regeneration

[84]

SF-SF

Rabbit

1 cm

3months

In vivo

Neurovascularized urethral tissue;

Wide caliber

[87]

BAMH/SF

Rabbit

2.5 cm

3months

In vivo

Promote vascularization;

Promote regeneration of urothelium and smooth muscle;

Wide caliber

[89]

BAMG/SF

rabbit

1.5 cm

3months

In vivo

Enhance cell adhesion and proliferation;

Reduce collagen deposition;

Promote vascularization

[91]

BC-SF

canine

5 cm

3months

In vivo

High porosity;

Facilitate cell adhesion and proliferation;

Promote angiogenesis

[93]

PLLA/PLGA/PCL-PLLA/PLGA/PLCL

Rabbit

2 cm

6months

In vivo

layered repair of urethra;

wide caliber

[95]

Collagen/

Elastin

NA

NA

NA

In vitro

Mimic natural structure;

Excellent mechanical properties;

Promote cell infiltration

[96]

Tri-layer composite scaffolds

PLA-PHBV-PLA

NA

NA

28days

In vitro

None-immunogenicity;

High mechanical strength

[97]

PLLA/

Gelatin

Rabbit

2.2 cm

3months

In vivo

Oriented SMC;

Wide caliber;

Promote angiogenesis

[102]

Collagen-PCL-collagen

NA

NA

14days

In vitro

Facilitate cell adhesion and proliferation;

High mechanical strength

[103]

PU-alt copolymer

Rabbit

2.2 cm

3months

In vivo

Promote the expression of α-SMA and AE1/AE3;

Induce immune cell apoptosis;

Simulate urethral structure

[107]

PU-alt copolymer

canine

2.2 cm

3months

In vivo

Promote vascularization;

Mimic natural structure;

Good mechanical properties

[109]

PCL/PLCL

NA

NA

NA

In vitro

High porosity;

High mechanical strength

[111]

Other multilayer scaffolds

SIS

Rabbit

1 cm

9months

In vivo

Complete urothelium layers;

No effective aggregation of smooth muscle cells

[112]

SIS

NA

Average 2.7 cm

Average

23months

In vivo

Insufficient mechanical strength and degradation;

Affect cell adhesion and proliferation

[113]