Bioactive Inorganic and Organic Composite Materials for Bone Regeneration and Gene Delivery - Advanced Bioactive Inorganic Materials for Bone Regeneration and Drug Delivery - page 179

Stem cells

Tissue
engineering

Biochemical
factors

Scaolds

FIGURE 7.1
The three main pillars that support bone tissue engineering: cells, scaffolds, and biochemical
factors.

Therefore, people are thinking about the compounds of the inorganic and
organic materials to solve its problems and to strengthen its benign proper-
ties. First, the addition of bioactive phases to polymers offers a pH buffering
effect at the polymer surface, thus acceleration of acidic degradation of the
polymer can be controlled. Second, by control of the structure and volume of
fraction, the composite materials can avoid the erosion of degradation. Third,
composite materials are able to absorb water due to the internal interfaces
formed between the polymer and more hydrophilic bioactive phases.
Gene therapy has become one of the most promising methods to treat
disease by delivering nucleotide sequence, principally DNA and various
types of RNA including antisense RNA, siRNA, isRNA, and miRNA, into
a specific cell population, thereby expressing successfully to manipulate
cellular activity, which in turn synthesizes functional proteins to stimulate
immune responses or tissue regeneration, or blocks expression at the level
of transcription or translation for treatment of several diseases (Piskin et
al. 2004; Wagner and Bhaduri 2012). The classic approach to gene therapy
consists of three elements: (1) an expression gene coding a specific thera-
peutic protein, (2) target cells such as stem cells or precursor cells, and (3)
a gene delivery system that delivers the gene into the target cells (Schaffer
and Lauffenburger 1998; Piskin et al. 2004). The gene delivery system is one
of the most important elements of the therapeutic performance required of
these features including high transfection efficacy, desirable biodistribution,
appropriate degradation rate, and bioactivity to facilitate the intracellular
trafficking of the gene expression system (Sundaram et al. 2009).
Traditionally, there are two different strategies to effectively deliver the tar-
get gene to the proper cells or tissues with a vector or without a vector (Luo
and Saltzman 2000). The gene delivery system without a vector (mainly by
physical methods) is difficult to control and optimize in vivo restricting its
study and application (Kamimura et al. 2011). On the other hand, most gene