Feirong Gong

Publications (2)3.06 Total impact

• Article: Novel branched poly(l-lactide) with poly(glycerol-co-sebacate) core

  Shujun Cheng, Lijing Yang, Feirong Gong
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  ABSTRACT: A series of biodegradable poly (glycerol-sebacate-l-lactide) (PGSLA) copolymers, with variable PLLA length, were synthesized and characterized. The copolymers comprised PGS backbone chain with a nominal molecular weight of 2,800g/mol. The length of each PLLA side chain covered the 800–14,000 range, while the length of the PLLA was easily controlled by the feed molar ratio of the l-lactide to the PGS. The structure of the copolymer was studied by nuclear magnetic resonance spectroscopy and gel permeation chromatography. Differential scanning calorimetric measurements and thermal gravimetric analysis had been performed to indicate the glass transition temperature (T g), melting point (T m), and the degree of crystallinity (χ c). It was also found that the onset decomposition temperature (T d) of the copolymers was lower than those of the linear polylactide (LPLLA). After solution casting and solvent evaporation, porous structures were found in the copolymer films by scanning electron microscope (SEM). Water contact angle results showed that the hydrophilicity of the copolymers was much higher than that of linear PLLA. In vivo, PGSLA copolymer demonstrated a favorable tissue response profile compared to PGS/LPLLA blend. There was also significantly less inflammation and fibrosis during degradation. PGSLA might therefore serve as an excellent candidate material for medical applications, given its minimal in vivo tissue response. KeywordsPolylactide-PGS-Branched-Copolymer
  Polymer Bulletin 04/2012; 65(7):643-655. · 1.53 Impact Factor
• Article: Novel side chain dendronized polyurethane: synthesis, characteristics, and cell responses

  Ju Rao, Feirong Gong, Shujun Cheng, Jianding Chen
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  ABSTRACT: Novel side chain dendronized polyurethane was synthesized by the sequential conjugation of amine-terminated fourth generation polyester dendrons with carboxyl groups at the side chain of polyurethane and deprotection of acetonide groups at the surface of dendrons. The effect of each step on the properties of the polymers was measured by GPC, DSC, SEM, AFM, and water contact angle measurement. The results showed that immobilization of polyester dendrons improve the compatibility of hard and soft segments in polyurethane and decrease the tendency of crystallinity due to the bulkiness of the substituents. After deprotection of the acetonide groups, both bulk and surface hydrophilicity of the polymer were evidently enhanced. Cell toxicity analysis showed that the side chain dendronized polyurethane synthesized in this study has exhibited excellent biocompatibility to human embryonic kidney 293T cells. The cells can effectively adhere to and proliferate on the surface of the polymer film. Overall, the present study demonstrated an efficient modification method for polyurethanes to improve their cell compatibility with high potential in biomedical applications.
  Polymer Bulletin 04/2012; 62(6):867-879. · 1.53 Impact Factor