Liying Cheng

bFGF-grafted electrospun fibrous scaffolds via poly(dopamine) for skin wound healing

Electrospun fibrous membranes coated with basic fibroblast growth factor (bFGF) are effective medical devices to promote wound healing. However, the current strategies of adding bFGF generally cause degradation of electrospun materials or damage to the bioactivity of the biomolecules. Here, we have developed a simple strategy for surface bFGF-functionalization of electrospun fibers in an aqueous solution, which maintained original fiber properties and growth factor bioactivity. Polydopamine (PDA) forming the mussel foot protein was chosen as an adhesive polymeric bridge-layer between substrate poly(lactide-co-glycolide) (PLGA) fibers and bFGF. The bFGF-grafted PDA was analyzed using scanning electron microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy. Improved hydrophilicity together with a stable fibrous structure and biodegradable fibrous matrix suggested that the PLGA/PDA-bFGF electrospun fibrous scaffolds have great potential for promoting wound healing. In vitro experiments showed that the bFGF-grafted PLGA electrospun fibrous scaffolds have highly enhanced adhesion, viability, and proliferation of human dermal fibroblasts. In vivo results showed that such scaffolds shortened wound healing time, accelerated epithelialization and promoted skin remodeling. Therefore, this PDA modification method can be a useful tool to graft biomolecules onto polymeric electrospun fibrous scaffolds which are potential scaffold candidates for repairing skin tissue.

Use of ginsenoside Rg3-loaded electrospun PLGA fibrous membranes as wound cover induces healing and inhibits hypertrophic scar formation of the skin

Prevention of hypertrophic scar formation of the skin requires a complex treatment process, which mainly includes promoting skin regeneration in an early stage while inhibiting hypertrophic formation in a later stage. Electrospinning PLGA with the three-dimensional micro/nano-fibrous structure and as drugs carrier, could be used as an excellent skin repair scaffold. However, it is difficult to combine the advantage of nanofibrous membranes and drug carriers to achieve early and late treatment. In this study, Ginsenoside-Rg3 (Rg3) loaded hydrophilic poly(D,L-lactide-co-glycolide) (PLGA) electrospun fibrous membranes coated with chitosan (CS) were fabricated by combining electrospinning and pressure-driven permeation (PDP) technology. The PDP method was able to significantly improve the hydrophilicity of electrospun fibrous membranes through surface coating of the hydrophilic fibers with CS, while maintaining the Rg3 releasing rate of PLGA electrospun fibrous membranes. Experimental wounds of animal covered with PDP treated fibrous membranes completely re-epithelialized and healed 3-4 days earlier than the wounds in control groups. Scar elevation index (SEI) measurements and histologic characteristics revealed that Rg3 significantly inhibited scar formation 28 days post-surgery. Moreover, RT-PCR assays and western blot analysis revealed that at day 28 after wound induction the expression of VEGF, mRNA and Collagen Type I in the scars treated with Rg3 was decreased compared to control groups. Taken together PLGA-Rg3/CS electrospun fibrous membranes induced repair of tissue damage in the early stage and inhibited scar formation in the late stage of wound healing. These dual-functional membranes present a combined therapeutic approach for inhibiting hypertrophic scars of the skin.

Surface biofunctional drug-loaded electrospun fibrous scaffolds for comprehensive repairing hypertrophic scars.

Incorporation of bioactive drugs and biofunctionalization of polyester fibrous scaffolds are essential means to improve their bio-functions and histocompatibility for regenerative medicine. However, it is still a challenge to biofunctionalize such drug carriers via traditional biochemical methods while maintaining their properties without changes in drug activity and loading ratio. Here, we demonstrated a facile approach for biofunctionalization of PLGA fibrous scaffolds with various molecules (i.e., PEG polymer, RGD peptide and bFGF growth factor for cell repellent, adhesion and proliferation, respectively) via mussel-Inspired poly(dopamine) (PDA) coating in aqueous solution. By virtue of the mild and efficient nature of this approach, the drug-loaded PLGA fibers could be easily biofunctionalized and showed negligible effects on the scaffold properties, especially drug activity and loading ratio. Further, in vivo study showed that, a ginsenoside-Rg3-loaded fibrous scaffold functionalized with bFGF growth factor could not only promote the early-stage wound healing in rabbit ear wounds (bio-signal from bFGF), but also inhibit later-stage hypertrophic scars formation (release of Rg3 drug). Therefore, the mussel-inspired method for bio-modification provides a facile and effective strategy to combine drug and bio-function in one system, thus facilitating a synergistic effect of drug-therapy and bio-signal when such biomaterial is used for regenerative medicine.

Electrospun poly(L-lactide) fiber with ginsenoside rg3 for inhibiting scar hyperplasia of skin.

Hypertrophic scarring (HS) has been considered as a great concern for patients and a challenging problem for clinicians as it can be cosmetically disfiguring and functionally debilitating. In this study, Ginsenoside Rg3/Poly(l-lactide) (G-Rg3/PLLA) electrospun fibrous scaffolds covering on the full-thickness skin excisions location was designed to suppress the hypertrophic scar formation in vivo. SEM and XRD results indicated that the crystal G-Rg3 carried in PLLA electrospun fibers was in amorphous state, which facilitates the solubility of G-Rg3 in the PLLA electrospun fibrous scaffolds, and solubility of G-Rg3 in PBS is increased from 3.2 µg/ml for pure G-Rg3 powders to 19.4 µg/ml for incorporated in PLLA-10% fibers. The released G-Rg3 content in the physiological medium could be further altered from 324 to 3445 µg in a 40-day release period by adjusting the G-Rg3 incorporation amount in PLLA electrospun fibers. In vitro results demonstrated that electrospun G-Rg3/PLLA fibrous scaffold could significantly inhibit fibroblast cell growth and proliferation. In vivo results confirmed that the G-Rg3/PLLA electrospun fibrous scaffold showed significant improvements in terms of dermis layer thickness, fibroblast proliferation, collagen fibers and microvessels, revealing that the incorporation of the G-Rg3 in the fibers prevented the HS formation. The above results demonstrate the potential use of G-Rg3/PLLA electrospun fibrous scaffolds to rapidly minimize fibroblast growth and restore the structural and functional properties of wounded skin for patients with deep trauma, severe burn injury, and surgical incision.

In vivo inhibition of hypertrophic scars by implantable ginsenoside-Rg3-loaded electrospun fibrous membranes.

Clinically, hypertrophic scarring (HS) is a major concern for patients and has been a challenge for surgeons, as there is a lack of treatments that can intervene early in the formation of HS. This study reports on a Chinese drug, 20(R)-ginsenoside Rg3 (GS-Rg3), which can inhibit in vivo the early formation of HS and later HS hyperplasia by inducing the apoptosis of fibroblasts, inhibiting inflammation and down-regulating VEGF expression. Implantable biodegradable GS-Rg3-loaded poly(l-lactide) (PLA) fibrous membranes were successfully fabricated using co-electrospinning technology to control drug release and improve drug utilization. The in vivo releasing time of GS-Rg3 lasts for 3 months, and the drug concentration released in rabbits can be controlled by varying the drug content of the electrospun fibers. Histological observations of HE staining indicate that GS-Rg3/PLA significantly inhibits the HS formation, with obvious improvements in terms of dermis layer thickness, epidermis layer thickness and fibroblast proliferation. The results of immunohistochemistry staining and Massons trichrome staining demonstrate that GS-Rg3/PLA electrospun fibrous membranes significantly inhibit HS formation, with decreased expression of collagen fibers and microvessels. VEGF protein levels are much lower in the group treated with GS-Rg3/PLA eletrospun membranes compared with other groups. These results demonstrate that GS-Rg3 is a novel drug, capable of inhibiting the early formation of HS and later HS hyperplasia. GS-Rg3/PLA electrospun membrane is a very promising new treatment for early and long-term treatment of HS.

Electrospun Ginsenoside Rg3/poly(lactic-co-glycolic acid) fibers coated with hyaluronic acid for repairing and inhibiting hypertrophic scars

Studies have explored many approaches to prevent and treat hypertrophic scars. However, most of them inhibit hypertrophic scars after their formation, without taking into account repairing tissue damage in the early stage and inhibiting scar hyperplasia in the late stage through combining treatments. In this study, Ginsenoside Rg3 (Rg3) loaded poly(d,l-lactide-co-glycolide) (PLGA) electrospun fibrous scaffolds were prepared by a co-solvent electrospinning method, and then hyaluronic acid (HA) was coated on the surface of the drug-loaded electrospun fibers by a pressure-driven permeation (PDP) wrapped method. The hydrophilic Rg3/PLGA/HA electrospun fibrous scaffolds showed the effect of combining treatments of promoting wound healing in the early stage and inhibiting scar hyperplasia in the late stage. The improved hydrophilicity together with a proper porous structure, a stable fibrous structure, durable mechanical properties and a similar drug release model suggested that the Rg3/PLGA electrospun scaffold coated with HA via PDP has great potential for drug-loaded tissue engineering scaffolds. The in vivo animal results showed that the Rg3/PLGA/HA could promote wound healing earlier and significantly inhibit scar hyperplasia compared to other control groups from macroscopic, histologic evaluation, and expression of collagen type I. The Rg3/PLGA/HA electrospun fibrous scaffolds open a new combined therapeutic approach for inhibiting hypertrophic scars.

In Vivo Early Intervention and the Therapeutic Effects of 20(S)-Ginsenoside Rg3 on Hypertrophic Scar Formation

Background Intra-lesional injections of corticosteroids, interferon, and chemotherapeutic drugs are currently the most popular treatments of hypertrophic scar formation. However, these drugs can only be used after HS is formed, and not during the inflammatory phase of wound healing, which regulates the HS forming process. Objective To investigate a new, effective, combining therapeutic and safe drug for early intervention and treatment for hypertrophic scars. Methods Cell viability assay and flow cytometric analysis were studied in vitro. Animal studies were done to investigate the combining therapeutic effects of 20(S)-ginsenoside Rg3 (Rg3) on the inflammatory phase of wound healing and HS formation. Results In vitro studies showed that Rg3 can inhibit HS fibroblasts proliferation and induce HSF apoptosis in a concentration-dependent manner. In vivo studies demonstrated that Rg3 can limit the exaggerated inflammation, and do not delay the wound healing process, which indicates that Rg3 could be used as an early intervention to reduce HS formation. Topical injection of 4 mg/mL Rg3 can reduce HS formation by 34%. Histological and molecular studies revealed that Rg3 injection inhibits fibroblasts proliferation thus reduced the accumulation of collagen fibers, and down-regulates VEGF expression in the HS tissue. Conclusion Rg3 can be employed as an early intervention and a combining therapeutic drug to reduce inflammation and HS formation as well.

Two-dimensional electrospun nanofibrous membranes for promoting random skin flap survival

Random skin flaps are widely used for repairing and reconstructing tissue defects and local tissue loss, and efforts to improve the survival of random skin flaps are continually being developed. Biomaterial scaffolds provide a microstructure for cell growth. However, the conventional three-dimensional structure can cause large foreign body reactions in the local subcutaneous tissue leading to fibrosis in order to block the blood perfusion of the skin flap. In this study, the effect of two-dimensional electrospun nanofibrous membranes on random skin flaps survival was investigated. Both typical nanofibrous membranes of synthetic (poly(L-lactide)) and natural (gelatin) materials were fabricated and analyzed using scanning electron microscopy, uniaxial tensile and water contact angle measurements. Both kinds of membranes maintained stable fibrous structures, but the natural fiber showed a better adhesion and viability for human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs) compared to synthetic fibers. In vivo experiments showed that natural electrospun nanofibrous membranes had faster degradation, better revascularization, and caused less inflammation, leading to an improved random skin flap survival. Therefore, electrospun fibrous membranes made of natural materials are more advantageous for random skin flap survival compared to the synthetic ones, and may be used as carrier implantation materials for improving skin flap survival rate.

Ginsenoside Rg3 inhibits keloid fibroblast proliferation, angiogenesis and collagen synthesis in vitro via the TGF‑β/Smad and ERK signaling pathways

A wide range of therapeutic options exists for the treatment of keloids, all of which have their own strengths; however, a high risk of side-effects and frequent recurrence remains. Therefore, the present study aimed to identify improved therapeutic approaches or drugs for the treatment of keloids. Ginsenoside Rg3 (Rg3) has been reported to exert numerous antitumor effects, thus indicating that Rg3 may be a potential therapeutic agent that targets keloids. The present study determined the effects of Rg3 on human keloid fibroblasts (KFs) in vitro, and further explored the associated molecular and cellular mechanisms. Keloid scar specimens were obtained from patients, aged between 22 and 35 years, without systemic diseases and primary cells were isolated from keloid tissues. In each assay, KFs were divided into three groups and were cultured in medium with or without various concentrations of Rg3 (50 or 100 μg/ml). Cell viability assay, flow cytometry, quantitative polymerase chain reaction, cell migration assay, immunofluorescence staining, western blot analysis, Transwell cell invasion assay and immunohistochemical analysis were used to analyze the KFs and keloid explant cultures. The results of the present study demonstrated that Rg3 was able to exert an inhibitory effect on the transforming growth factor-β/Smad and extracellular signal-regulated kinase signaling pathways in KFs. The proliferation, migration, invasion, angiogenesis and collagen synthesis of KFs were markedly suppressed following treatment with Rg3. Furthermore, the results of an ex vivo assay indicated that Rg3 inhibited angiogenesis and reduced collagen accumulation in keloids. Significant statistical differences existed between the control and Rg3-treated groups (P<0.05). All of these experimental results suggested that Rg3 may serve as a reliable drug for the treatment of patients with keloids.

An update review on recent skin fillers

Facial rejuvenation has changed over the last decade, evolving from the rhytidectomy to an approach that focuses on revolumization, due to a more complete understanding of the changes to bone and soft tissue that occur with the aging face. Soft tissue augmentation using various injectable filler agents has gained popularity due to their nonsurgical, non-invasive procedures, instant cosmetic outcomes and limited recovery time. The skin filler market is booming and the variety of available skin fillers is increasing, providing the plastic surgeons many choices. Nonpermenant, biodegradable, resorbable agents may induce little complications, but they will normally disappear soon after injection. Semipermenant, biodegradable, biostimulary, nonresorbable fillers may induce a bit more complications, but they will normally disappear spontaneously in a few months. Permanent, nonresorbable fillers usually give rise to severe complications or reactions which may not disappear spontaneous. They may appear several years after the injection, and treatment is often insufficient. Unfortunately, the ideal filler with lasting effect but without any complication has not been discovered yet. In this review, we give an update on currently available skin filler agents, and what is new in recent 5 years.