# Influence of Solvent Selection in the Electrospraying Process of Polycaprolactone
## 5 The Applications of Electrosprayed PCL Particles
### Tissue Engineering  
As a three-dimensional and degradable material, electrospray PCL microspheres are also used in the tissue engineering field as biologically active and temporary devices to achieve repairing and regenerating of tissue, supporting and reinforcement [11]. In order to promote tissue growth, the microspheres scaffolds with porous morphology is one the best candidates. On the one hand, the contacting area as well as interactions between microsphere scaffolds and cells increases with increasing the specific surface area of microsphere scaffolds. On the other hand, due to the presence of porous structure, cells can penetrate the pores, which must be interconnected to improve nutrient and waste exchanges by cells [95]. The degradation rate of PCL microsphere scaffolds is also a crucial factor to influence their applications in tissue engineering, and it is controlled effectively by designing the structure and morphology of PCL microspheres. At the same time, the size and shape of electrospray PCL microparticles can be designed carefully according to a specific application. Also, to further improve the ability of cell adhesion as well as degradation properties, gelatin or collagen is  
\begin{table}
\begin{tabular}{c c c c c} \hline
**PCL Molecular** & **Mean Diameter** & **Morphology** & **Potential Applications** & **Reference** \\
**Weight (g/mol)** & **(g/mol)** & **(g/mol)** & **(g/mol)** & **(g/mol)** \\ \hline
65,000 & 7-11 & Spherical, smooth and compact & Control release of anticancer drug & [94] \\
14,000 & 0.3-5 & Smooth and compact & Drug control release & [127] \\
80,000 & 0.2–4.5 & Smooth and compact & Drug delivery system & [163] \\
80,000 & 0.63-0.65 & Spherical, smooth and compact & Control release and drug delivery & [164] \\
45,000 & 5-20 & Porous and wrinkled & Control release and drug delivery & [152] \\
80,000 & 0.72–3.5 & Spherical shape, porous and fibeless & Tissue engineering & [165] \\
80,000 and 45,000 & 125–450 & Porous, loose and spherical & Tissue engineering and cell therapy & [162] \\
4500 & 10–15 & Yolk-shell, smooth and spherical & Biomedical engineering & [166] \\
80,000 & 0.4–2 & Fibrous and smooth & Tissue engineering & [167] \\
41,000 & 14–18 & Fibrous, wrinkle and porous & Tissue engineering & [168] \\
80,000 & 0.7–2.5 & Nanofilor, wrinkle and compact & Food packaging (Vitamin) & [169] \\
10,000 & 0.5–4.5 & Fibrous and smooth & Refrigeration and food packaging & [170] \\
10,000 & 0.1–2.5 & Fibrous and smooth & Refrigeration and food packaging & [171] \\ \hline \end{tabular}
\end{table}
Table 6: Applications of electrospray PCL microparticles with different sizes and morphologies.  
blended with PCL to prepare scaffolds or supporting materials used in the biomedical field [176; 177; 178]. Collagen and gelatin contain Arg-Gly-Asp (RGD) amino acid sequences. Then, integrins (cell binding proteins) recognize those sequences and promote cell adhesion. This biopolymer addition increases cell attachment and spreading to the surface of a material.  
Furthermore, electrosprayed drug-PCL microcapsules are also coated on the surface of degradable electrospun fibers to be used in tissue engineering, particularly in bone and cartilage tissue engineering [95]. During the process of cells regeneration in scaffolds, the controlling release of active drug from microcapsules provides a sustained and suitable environment to improve the activity and growth of cells [11]. In 2009, [PERSON] et al. firstly fabricated a soft tissue engineered construct (TEC) with anisotropic structure via combining coaxial electrospraying and electrospinning [173]. The release of insulin-like growth factor from microcapsules coating on the surface of scaffolds can deliver growth factors for the survival of cells, which are often subjected to hypoxia and a nutrient starvation microenvironment in the context of TECs.