PP
Polypropylene
PSU
Polysulfone
PTFE
Polytetrafluoroethylene
PUs
Selected polyurethanes
PVC
Poly(vinyl chloride)
UHMWPE Ultrahigh molecular weight polyethylene
1 Introduction
Bone is one of the most commonly replaced tissues, and bone grafts can efficiently
repair fractures in bones of the human body. Small defects are usually repaired by the
growth of natural bone that is even stronger than the original bone. The bone is
naturally regenerated within a few weeks. However, problems arise with major
fractures, i.e., large defects that are not repaired by the body. Spinal fusion (arthrodesis), fracture non-unions, skeletal deformities caused by infection, trauma, or tumor
resection are examples of such cases where bone healing needs to be improved [1].
Bone grafts are generally used in such cases. Basically, bone grafting is a surgical
process that replaces missing bone with the help of bone graft materials in order to
repair complex bone fractures in normal healthy bone without damaging living
tissue. Bone graft requirements truly depend on the complication of the bone defects.
There are a number of bone grafting methods available for the repair of bone defects.
Among these, autografting and allografting are commonly used methods. In the
autograft technique, bone from a different part of the body is transferred. However,
there are some practical complications associated with this method, such as
complications in wound healing, extra surgery, donor pain, and limited supply of
bone [2]. In the allograft technique, bones from living donors or cadavers are used
and the risks associated with this method include rejection and disease transmission,
along with a significant structural failure rate due to poor tissue integration [3–6]
These limitations and concerns have attracted significant interest in the development
of synthetic bone grafts that are equivalent to natural bone tissue in all aspects [7]. A
biodegradable and bioactive material is one of the essential components for the
development of synthetic bone grafting and a limited number of such materials are
available. Among others, chitosan (CTS), a natural polysaccharide derived from
chitin, and hydroxyapatite (HAp) serve as the best bioactive biomaterials in bone
grafting and are well known for their excellent biocompatibility with the human
body environment [8]. Recently, polymer/ceramic composites and nanocomposites
consisting of a polymer matrix and bioactive micro- or nanofiller have been utilized
as novel bone substitutes. The advantages offered by using polymers in this regard
include structural stability, biocompatibility, and preferred shape, which are combined with the characteristics of ceramics that mimic those of bone structure. One of
the most important groups of polymer/ceramic composites are polymer/HAp
materials. HAp has attracted much attention as a biomaterial because its chemical
composition is identical to that of human bone. HAp is a highly biocompatible,
Hydroxyapatite-Packed Chitosan-PMMA Nanocomposite: A Promising Material for. . .
137
Polypropylene
PSU
Polysulfone
PTFE
Polytetrafluoroethylene
PUs
Selected polyurethanes
PVC
Poly(vinyl chloride)
UHMWPE Ultrahigh molecular weight polyethylene
1 Introduction
Bone is one of the most commonly replaced tissues, and bone grafts can efficiently
repair fractures in bones of the human body. Small defects are usually repaired by the
growth of natural bone that is even stronger than the original bone. The bone is
naturally regenerated within a few weeks. However, problems arise with major
fractures, i.e., large defects that are not repaired by the body. Spinal fusion (arthrodesis), fracture non-unions, skeletal deformities caused by infection, trauma, or tumor
resection are examples of such cases where bone healing needs to be improved [1].
Bone grafts are generally used in such cases. Basically, bone grafting is a surgical
process that replaces missing bone with the help of bone graft materials in order to
repair complex bone fractures in normal healthy bone without damaging living
tissue. Bone graft requirements truly depend on the complication of the bone defects.
There are a number of bone grafting methods available for the repair of bone defects.
Among these, autografting and allografting are commonly used methods. In the
autograft technique, bone from a different part of the body is transferred. However,
there are some practical complications associated with this method, such as
complications in wound healing, extra surgery, donor pain, and limited supply of
bone [2]. In the allograft technique, bones from living donors or cadavers are used
and the risks associated with this method include rejection and disease transmission,
along with a significant structural failure rate due to poor tissue integration [3–6]
These limitations and concerns have attracted significant interest in the development
of synthetic bone grafts that are equivalent to natural bone tissue in all aspects [7]. A
biodegradable and bioactive material is one of the essential components for the
development of synthetic bone grafting and a limited number of such materials are
available. Among others, chitosan (CTS), a natural polysaccharide derived from
chitin, and hydroxyapatite (HAp) serve as the best bioactive biomaterials in bone
grafting and are well known for their excellent biocompatibility with the human
body environment [8]. Recently, polymer/ceramic composites and nanocomposites
consisting of a polymer matrix and bioactive micro- or nanofiller have been utilized
as novel bone substitutes. The advantages offered by using polymers in this regard
include structural stability, biocompatibility, and preferred shape, which are combined with the characteristics of ceramics that mimic those of bone structure. One of
the most important groups of polymer/ceramic composites are polymer/HAp
materials. HAp has attracted much attention as a biomaterial because its chemical
composition is identical to that of human bone. HAp is a highly biocompatible,
Hydroxyapatite-Packed Chitosan-PMMA Nanocomposite: A Promising Material for. . .
137