**2. Materials and methods**

#### **2.1. Preparation of scaffolds with different PLA contents**

10 mg of unwoven PGA fibers (provided by Dong Hua University, Shanghai, China) were compressed into a cylinder shape of 5mm in diameter and 2mm in thickness. A solution of 0.3 % PLA (Sigma, St. Louis, MO, USA) in dichloromethane was evenly dropped onto the PGA scaffold, dried in a 65 ºC oven, and weighed. The PLA mass ratio was calculated according to the formula: PLA%= (final mass-original mass)/final mass×100%. The above procedures were repeated until the predetermined PLA mass ratios of 0%, 10%, 20%, 30%, 40% and 50% were achieved. The scaffolds were examined by SEM (Philips XL-30, Amsterdam, Netherlands) [18].

#### **2.2. Biocompatibility evaluation of the scaffolds**

**Cell seeding:** Chondrocytes were isolated from the articular cartilage of newborn swine (2-3weeks old) as previously described [19]. The harvested chondrocytes were adjusted to a final concentration of 50×106 cells/mL, and a 100uL cell suspension was pippeted onto each scaffold. The cell-scaffold constructs were then incubated for 4h at 37ºC with 95% humidity and 5% CO2 to allow for complete adhesion of the cells to the scaffolds.

**Cell adhesion:** After 4 hours of incubation, the cell-scaffold constructs were gently transferred into a new 6-well plate. The remaining cells were collected and counted. The cell seeding efficiencies of the scaffolds with different PLA contents were calculated based on the formula: (total cell number- remaining cell number)/ total cell number×100% [14].

#### **2.3. Mold fabrication by CAD/CAM**

A patient's normal nose was scanned by CT to obtain the geometric data (Figure 3). These data were further processed by a CAD system to generate both positive and negative of the normal nose, and the resultant data were input into a CAM system (Spectrum 510, Z Corporation) for the fabrication of the resin models by 3D printing. The negative mold was composed of two parts: the anterior part and the posterior part. (Figure 4A)

#### **2.4. Fabrication of nose shaped scaffold**

Two hundred milligrams of unwoven PGA fibers were pressed using the negative mold for over 12 hours. A solution of 0.3 % PLA (Sigma, St. Louis, MO, USA) in dichloromethane was evenly dropped onto the PGA scaffold, dried in a 65 ºC oven, weighed, and pressed again with the negative mold. This procedure was repeated until the final PLA mass ratio of 20% was reached. The edge of the scaffold was carefully trimmed according to the shape of the positive mold.

#### **2.5. Statistical analysis**

The differences of cell seeding efficiencies (n=6) among the six PLA content groups were analyzed using the Student's t-test. A *p*-value less than 0.05 was considered statistically significant.
