# BMP-2 Delivery through Liposomes in Bone Regeneration
## 4 Transfection
HA ceramics have been used as a substitute for autologous bone or as a carrier for bioactive molecules. Adding liposomal BMP-2 cDNA to HA scaffolds leads to better bone formation than HA alone or liposomal BMP-2 alone. The BMP-2 expression was present at 3 and 6 weeks after which it decreased gradually [124]. Human amnion mesenchymal stem cells (hAMSC) transfected with BMP-2 in a liposomal formulation seeded on nano HA/collagen/poly(1-lactide) had a similar proliferation and differentiation capability as those cultured in osteogenic culture media. The cells transfected had higher expression of OC and Runx2 [125]. Recently, stem cells of buco-maxillar origin have been identified and isolated [8]. Dental follicle, alveolar bones, and ligaments have proven to be excellent sources of stem cells. They are readily available from discarded medical waste and have proven to be superior in osteogenesis as compared with stem cells of other origins. The periodontal ligament plays an important role in stability, nutrition, and regeneration of the teeth. Stem cells isolated from it have been successfully used for differentiation into osteoblasts when transfected with BMP-2 plasmids using a liposomal vector [126]. The studies conducted on liposomal delivery of BMP-2 through transfection are detailed in Table 2. \begin{table}
\begin{tabular}{l l l l l l l l} \hline
**Molecule(s)** & **Liposome/Substrate** & **Cells Used** & **In Vitro Testing** & **Animal Intervention** & **Examination** & **Citation** \\ \hline hBMP-2 & & & Immunohistochemical & & 8 Pigs with calvariat & Biopsy at 7 and 28 days & \\ (pCMVBMP-2 & NA & Pig BMSC & & & Green fluorescent & & Microradiography & \\ plasmid) & & & & protein (GFP) & & defects & Immunohistochemistry & \\ \hline BMP-2 & NA & - & - & - & 8 Domestic pigs with & & Microradiography & \\  & & & & & calvariat defects & trichrome staining, light & \\  & & & & & microscopy & \\ \hline \end{tabular}
\end{table} 
Table 2: Transfection of BMP-2 genes. \begin{table}
\begin{tabular}{l l l l l l l l} \hline
**Molecule(s)** & **Liposome/Substrate** & **Cells Used** & **In Vitro Testing** & **Animal Intervention** & **Examination** & **Citation** \\ \hline BMP-2/VEGF\({}_{165}\) & plRES & Mouse BMSC & RT-FCR: BMP-2 and VEGF165 & 4 Male nude mice, injection in thigh muscle & Digital radiography for ectopic bone formation at 4 weeks & [115] \\  & & Immunohistochemistry & pouch & benatomy/insulin-cesin & \\ \hline  & & & RT-FCR: BMP-2 and & & & \\  & & & VEGF165 & & & \\ hBMP-2 & & & Human BMSC & VEGF165 & & \\ hVEGF165 & plRES & 14 days & RT-FCR: of OC mRNA & & & \\  & & Immunohistochemistry: & & & \\  & & & Collagen I & & & \\  & & & ALP activity assay & & & \\ \hline  & & & GFP & & & \\  & & & In situ hybridization & & & \\  & & & Immunohistochemical & & & \\ hBMP-2 & NA & Rat BMSC & & staining: OC, collagen I, QP & Rat mandibular critical size defect & Trichrome-Goldner & \\  & & & RT-FCR & & & \\  & & & Alizarin red: Calcium & & & \\  & & & deposits & & & \\ \hline  & & & Fluorescent microscopy & & & \\  & & & Flow cytometry: Cell & & & \\  & & & cycle analysis & & & \\  & & & Western blot & & & \\  & & & Q-PCR: mRNA BMP-2, GC & & & \\  & & & OC & & & \\  & & & Immunohistochemistry & & & \\  & & & ALP activity assay & & & \\ \hline BMP-2+ & & & Mouse & Hoechst 33285.