Electrospining Machine: Progressively degradable PGA-SF core-shell electrospinning scaffold with excellent wetting toughness for bone regeneration

Background

Oral and maxillofacial bone defects due to disease and trauma are a global concern due to their high morbidity, negative impact on quality of life and heavy economic burden. Implantation of bone graft materials is the most commonly used treatment for bone defects. However, non-biodegradable bone graft materials can lead to incomplete bone regeneration or even complete rejection by the organism due to the occupation of osteogenic space. Therefore, the development of degradable bone grafts has become an important direction for the repair of bone defects.

The main point of this paper

Clinically degradable bone graft materials:

Polymers, biodegradable bioceramics and magnesium metal are the three main materials currently used.

Limitations of polymer bone grafts:

Although polymers are morphologically customisable, have low immunogenicity and controlled degradation, acidic degradation products may lead to local pH changes, poor osteoconductivity and cell adhesion.

Advantages of composites:

Composites can provide complementary properties and overcome the limitations of homogeneous materials.

Properties of polyglycolic acid (PGA):

PGA has good initial mechanical properties but degrades rapidly and tends to induce sterile inflammation.

Application of Silk Vegetable Powder (SF):

Derived from silk, SF has perfect biocompatibility, adjustable multilayered structure, but its structural adjustment to achieve desired degradation and mechanical properties is challenging.

Study of SF/PGA blends:

SF/PGA blends have good osteoconductivity and histocompatibility, but cannot overcome the rapid degradation of PGA.

Application of electrospinning technology:

Nanofibrous scaffolds can mimic the structure of bone matrix, and coaxial electrospinning technology can combine the advantages of two polymers to improve the material stability

Coaxial PGA-SF fibre scaffolds: a study to optimise the degradation characteristics and osteogenic activity of bone graft materials

The Challenge of Bone Graft Materials:

Oral and maxillofacial bone regeneration is clinically challenging and requires the construction of bone graft materials with controlled degradation and stable mechanical properties

Advantages of PGA-SF-FS:

PGA-SF-FS is made using silk fibroin (SF) and polyglycolic acid (PGA), with the SF shell protecting PGA from rapid degradation while providing osteogenic activity and the PGA core providing toughness

Biocompatibility and osteogenic capacity:

PGA-SF-FS shows excellent ability to improve cell growth and osteogenic differentiation associated with biocompatibility and osteogenesis

In vivo test results:

In vivo testing using the Sprague-Dawley rat model of cranial bone defects demonstrated that PGA-SF-FS accelerated bone regeneration and that its gradual degradation properties helped to match the kinetics of remodelling of host bone tissue

Immunohistochemical staining results:

Immunohistochemical staining for CD31 and Col-1 confirmed the ability of PGA-SF-FS to enhance vascular regeneration and osteogenic response

Material properties:

PGA-SF-FS fully utilises the advantages of both components, with gradual degradation properties and superior toughness in the wetting mechanism, making it an ideal candidate for the treatment of osteoporosis

Molecular dynamics simulation (MDS):

The molecular mechanism of the aqueous environment on PGA-SF-FS was investigated by MDS to further understand the behaviour of the material in a physiological environment

Characterisation of material properties:

The morphology, mechanical properties, degradation behaviour and bioactivity of PGA-SF-FS, SF fibrous scaffold (SF-FS) and PGA fibrous scaffold (PGA-FS) were characterised

Summarize

PGA-SF-FS fabricated by coaxial electrospinning technology exhibits excellent toughness under wetting conditions and shows controlled gradual degradation.PGA-SF-FS significantly promotes cell adhesion, proliferation, and osteogenic differentiation in vitro, and supports angiogenesis and new bone formation in vivo.The controlled degradation behaviour, good ductility and osteoconductivity of PGA-SF-FS make it a promising candidate for the use as bone grafts and drug carriers for the treatment of bone defects. The controlled degradation behaviour, good ductility and osteoconductivity of PGA-SF-FS have great potential as bone grafts and drug carriers for the treatment of bone defects.