Table 8 Performance of composites, blends and hybrid materials based on natural and synthetic polymers for ligament/tendon TE

CHI-PCL-cellulose

Electrospun CHI-PCL nanofibers + cellulose nanocrystals: i) Aligned nanofibers

(ii) Random nanofibers

Tendon

In vitro (human tenocytes)

(i) 540.5 ± 83.7

(ii) ND

ND

(i) 39.3 ± 1.9

(ii) ND

ND

Cellular adhesion/spread

(i) Cells elongated/aligned along the nanofibers

(ii) Cells with random shape and orientation

Synthesis of tendon-specific markers

[83]

Silk-PLCL

Electrospun

(i) Aligned nanoyarn-reinforced random fibers (NRS)

(ii) Random nanofibers

(iii) Aligned nanofibers

In vitro (primary rat BMSCs)

(i) 288.95 ± 13.26

(ii) 186.65 ± 8.87

(iii) 433.56 ± 48.06

ND

(i) 24.25 ± 0.76

(ii) 9.70 ± 0.51

(iii) 39.10 ± 2.89

ND

BMSCs adhesion/spread

(i) Higher cell spread than (ii), (iii); cells elongation/random distribution

(ii) Cells with random distribution, pyramidal shape

(iii) Cellular elongation

[106]

Col-PLCL

Electrospun

(i) Nanoyarn

(ii) Random nanofibers

(iii) Aligned nanofibers

In vitro (primary rabbit tendon cells)

(i) ~ 2.1

(ii) ~ 3.9

iii) ~ 4.5

ND

(i) ~ 3.3

(ii) ~ 5.6

(iii) ~ 6.2

ND

Cell adhesion, spread

(i) Higher cell growth

(i), (ii) Elongation along the nanofibers/nanoyarn

(iii) Cells with random spread

(i) Higher tendon-ECM genes, compared to (ii), (iii), after 14 days

[107]

Col-PD^a

Electrospun

(i) Col nanofibers

(ii) Col microfibers coated with PD

Tendon

In vivo, rabbit model

(i) 0.549

(ii) 0.754 (60 days post surgery)

(i) 20.37

ii) 29.87 (60 days post surgery)

i) 10.44

(ii) 11.37 (60 days post surgery)

(i) 52.72

(ii) 74.02 (60 days post surgery)

(i), (ii) Some inflammatory response, after surgery

(ii) Cells with better alignment and higher mature tenoblasts and macrophages, compared to (i), 60 days post-surgery; Scaffold partially degraded

[119]

Col-Carbon nanofibers

Elongated gel-spun fibers: (i) Col/ 0.5 carbon nanochips crosslinked with glutaraldehyde

(ii) Col/ 0.5 carbon nanochips

(iii) Col/ 0.5SWNTs^b, crosslinked with glutaraldehyde

(iv) Col/ 0.5SWNTs

ND

(i) 590 ± 50

(ii) 46 ± 4

(iii) 840 ± 40

(iv) 92 ± 35 (wet-state)

ND

(i) 75 ± 15

(ii) 5 ± 2

(iii) 70 ± 8

(iv) 9 ± 1 (wet-state)

ND

ND

[109]

(PLLA-Col)-(PCL-Col)

Co-electrospun onto opposite ends: PLLA-Col

PCL-Col (3 regions)

In vitro (myoblastsand fibroblasts)

7.34 ± 2.13

ND

0.51 ± 0.21

ND

Myoblasts and fibroblasts adhesion/proliferation onto the 3 regions

Myoblasts differentiation into myotubes

[108]

Silk coated with PLGA

Knitted silk microfibers coated with

Random electrospun PLGA nanofibers

Ligament/tendon

In vitro (rabbit BMSCs)

ND

4.8 ± 0.52

ND

Cellular adhesion, proliferation

Production of ECM between the nanofibers

[120]

(i) bFGF-releasing electrospun PLGA nanofibers

(ii) Electrospun PLGA nanofibers

ND

(i) 4.3 ± 0.3

(ii) ND

ND

Cell adhesion/spread

(i) Higher cell proliferation, viability; higher Col production, ligament/tendon-specific ECM, from day 7 to 14, comparing to (ii)

[105]

Silk coated with PCL or P3HB^c

Twisted nanofiber-coated silk yarn Nanofiber coating: (i) PCL

(ii) P3HB

(iii) Electrospun PLGA nanofibers

In vitro (L929 murine fibroblasts)

ND

(i) 110.5 ± 6.6

(ii) 97.6 ± 11.4

(iii) 92.6  ± 8.2

Cell adhesion/spread

Cell viability decreased from the 1st to 3rd day of culture; (i), (ii) Higher cell viability than (iii), after 3 days of culture

[121]

PCL coated with Col

Electrospun PCL scaffold coated with: (i) Col

(ii) Col + bFGF

(iii) Col + hFF

(iv) Col + bFGF + hFF

Ligament

In vivo, rat model

ND

(i) 12.4 ± 3.8

(ii) 23.3 ± 8.1

iii) 4.4 ± 1.2

iv) 10.1 ± 2.1 (16 weeks post-surgery)

ND

(i) 16.0 ± 3.4

(ii) 23.1 ± 6.1

(iii) 17 ± 6.9

(iv) 15.1 ± 4.9

(16 weeks post-surgery)

Cell proliferation and alignment along the fibers; Col deposition

(ii) Higher cell proliferation than (i), at 16 weeks post-surgery

(iii), (iv) No beneficial effect of hFF for regeneration

[80]

PLCL (85/15)-poly-l-lysine-HA

Multilayer braid: (i) PLCL

(ii) PLCL+Poly-l-lysine

iii) PLCL + poly-l-lysine + HA

In vitro (human BMSCs and WJ-MSCs^d)

(i) 1616 ± 643

(ii) 1608 ± 156

(iii) 1758 ± 470

ND

Cell adhesion, proliferation, elongation and alignment; ECM synthesis on day 14; Metabolic activities decreased from (i) to (ii) and (iii)

(iii) Higher MSCs migration

[69]

PLLA-gelatin-Col

Gelatin-bFGF hydrogel sandwiched by Fn-coated PLLA braided scaffold, and wrapped with a Col membrane, reinforced with PLLA microspheres

In vivo, rabbit model

ND

~ 30

ND

At 8 weeks post-surgery, great cell spread/migration; vascularization induced by bFGF; great Col and ECM synthesis

[38]