Preparation of injectable and thermoresponsive hydrogel based on penta-block copolymer with improved sol stability and mechanical properties

Abandansari, Hamid Sadeghi; Aghaghafari, Elham; Nabid, Mohammad Reza; Niknejad, Hassan

doi:10.1016/j.polymer.2013.01.004

Cited by 42 publications

(38 citation statements)

References 44 publications

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“…The 1 H NMR of the PNIPAAm‐PCEC‐PNIPAAm consisting of a sharp peak at 1.12 ppm was related to CH 3 ─ of N ‐isopropyl acrylamide and the peaks at 6.22 and 5.96 ppm were assigned to N─H of N ‐isopropyl acrylamide (Figure B) these results were in accordance with the results of Abandansari et al…”

Section: Resultssupporting

confidence: 91%

Synthesis and evaluation of injectable thermosensitive penta‐block copolymer hydrogel (PNIPAAm‐PCL‐PEG‐PCL‐PNIPAAm) and star‐shaped poly(CL─CO─LA)‐b‐PEG for wound healing applications

Oroojalian

Jahanafrooz

Chogan

et al. 2019

J of Cellular Biochemistry

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Background Loss of skin integrity due to injury, burning, or illness makes the development of new treatment options necessary. Skin tissue engineering provides some solutions for these problems. Objective The potential of a biodegradable star‐shaped copolymer [Poly(CL─CO─LA)‐b‐PEG] and penta‐block copolymer hydrogel (PNIPAAm‐PCL‐PEG‐PCL‐PNIPAAm) was assessed for skin tissue engineering applications. Methods Two copolymers were synthesized for cellular culture scaffolds and their mechanical properties were compared. The resulting star‐shaped copolymer and thermosensitive penta‐block copolymer were characterized using Fourier transform infrared and nuclear magnetic resonance spectroscopy. The crystallizability of the two copolymers was analyzed using X‐ray diffraction. The resulting thermosensitive penta‐block copolymer was evaluated by differential thermal analysis, differential scanning calorimetry and thermogravimetric analysis. Scanning electron microscopy and in vitro degradation of the polymer network in phosphate buffer solutions (pH 7.4) at 37°C were also examined. The pore size of the gels was calculated with Image Analyzer software. Finally, the cytotoxic, morphological, and gene expression effects of copolymers on the skin fibroblast were evaluated. Results The experiments showed that the PNIPAAm‐PCL‐PEG‐PCL‐PNIPAAm polymer with the right composition and the expected molecular weight was achieved. The hydrogel had less crystallizability compared with its precursors. The resulting thermosensitive hydrogel had a three‐dimensional structure with interconnected pores that mimicked the extracellular matrix. The control of the degradability rate can be possible by weight percent changes. The pore size correlated with the polymer concentration in aqueous solution and the pore sizes of the 20 wt% hydrogel were better for fibroblast cultivation than those of the 10 wt% hydrogel. Cell proliferation on the 20% gel was more than that of the 10% gel. The hydrogel not only preserved the viability and phenotypical morphology of the entrapped cells but also stimulated the initial cell‐cell interactions and proliferation of fibroblasts. The hydrogel did not influence cell conformation and this property of the polymer underlined its safety. Cells seeded on this copolymer showed a normal and spear shape and formed a focal adhesion with the hydrogel surface. Notably, the hydrogel increased collagen I α1 and collagen III mRNAs expression. Conclusion Due to the low molecular weight and poor mechanical strength of the star‐shaped copolymer, it was not considered for fabrication of the scaffolds for wound healing. The biodegradable, biocompatible, injectable and thermosensitive PNIPAAm‐PCL‐PEG‐PCL‐PNIPAAm hydrogel in 20 wt% demonstrated a desirable potential for future application as a cell scaffold in skin tissue engineering and wound healing.

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Section: Resultssupporting

confidence: 91%

Synthesis and evaluation of injectable thermosensitive penta‐block copolymer hydrogel (PNIPAAm‐PCL‐PEG‐PCL‐PNIPAAm) and star‐shaped poly(CL─CO─LA)‐b‐PEG for wound healing applications

Oroojalian

Jahanafrooz

Chogan

et al. 2019

J of Cellular Biochemistry

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“…Polyethylene glycol (PEG) is often used as a hydrophilic block owing to its acceptable biocompatibility, protein repulsion, lack of toxicity, and immunogenicity [6]. The biodegradable and biocompatible polyesters such as polycaprolactone (PCL), poly(D,L-lactic acid) (PLA), polyglycolic acid (PGA), and poly(lactide-co-glycolic acid) (PLGA) have been introduced as hydrophobic blocks [7][8][9]. In 2007, paclitaxel (PTX)-loaded poly(ethylene glycol)-b-poly(lactic acid) (PEG-b-PLA), termed Genexol-PM, was approved in Korea for the treatment of breast and mid-to-large-sized lung cancer cells [7].…”

Section: Introductionmentioning

confidence: 99%

Engineering folate-targeting diselenide-containing triblock copolymer as a redox-responsive shell-sheddable micelle for antitumor therapy in vivo

et al. 2018

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On-demand drug actuation is highly desired. Redox-responsive polymeric DDSs have been shown to be able to respond and release their cargo in a selective manner when encountering a significant change in the potential difference, such as that present between cancerous and healthy tissues. This study offers an added advantage to the field of redox-responsive polymers by reporting a new type of shell-sheddable micelle based on an amphiphilic triblock co-polymer, containing diselenide as a redox-sensitive linkage. The linkage was smartly located at the hydrophilic-hydrophilic bridge in the co-polymer offering complete collapse of the micelle when exposed to the right trigger. The system was able to delay tumor growth and reduce toxicity in a breast cancer tumor model following intraperitoneal injection in mice.

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“…As 4HGF is dark brown in color, PGA-4HGF also appeared brownish (Figure 2A), whereas PGA-control without 4HGF appeared light white in color (Figure 2D), originating from the gel matrices only. Although it is relatively difficult to correctly visualize hydrogels by TEM and SEM analyses due to their water evaporation during the sample preparation and analyses,8,27,28 we could observe approximately 400 nm-sized spherical particles of PGA-4HGF, which might have a higher content of gel matrices with less water content. Interestingly, smaller-sized (~300 nm) PGA-control particles were seen, indicating that the entrapment of 4HGF may enlarge the size of the nanoparticles.…”

Section: Resultsmentioning

confidence: 87%

<p>Poly(γ-Glutamic Acid)/Chitosan Hydrogel Nanoparticles For Effective Preservation And Delivery Of Fermented Herbal Extract For Enlarging Hair Bulb And Enhancing Hair Growth</p>

Kim¹,

Kwon²,

Lee³

et al. 2019

IJN

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IntroductionHair growth-promoting herbal extract mixtures (4HGF) exhibits significant anti-inflammatory activities relevant to promoting hair growth; however, its efficacy in patients with hair loss has been limited majorly due to its low penetration ability into hair follicles. Herein, we prepared hydrogels via dropwise addition of poly(γ-glutamic acid) (PGA) solution containing 4HGF into chitosan (CS) solution, resulting in quick formation of ~400 nm-sized hydrogel particles through electrostatic interaction-derived ionic gelation with over 50% encapsulation efficiency of 4HGF (PGA-4HGF).MethodsThe size and morphology of PGA-4HGF were characterized by TEM, SEM, and dynamic light scattering analyses. Encapsulation efficiency and loading capacity of 4HGF within PGA-4HGF, as well as in vitro release profiles were determined by simply measuring the characteristic absorbance of 4HGF. Penetrating efficiency of PGA-4HGF was evaluated by tracking the respective fluorescence through model porcine skin with confocal laser microscope system. By treating PGA-4HGF on telogenic mice and dermal papilla cells (DPCs), we evaluated the size of hair bulbs in mice, as well as morphological changes in DPCs.ResultsNegligible and sustained release of entrapped 4HGF from the hydrogel nanoparticles were observed under acidic and physiological pH conditions, respectively, which is quite advantageous to control their release and prolong their hair growth-promoting effect. The hydrogel nanoparticles were penetrable through the porcine skin after incubation with or without shaking. After treating telogenic mice and DPCs with PGA-4HGF, we detected enlargement of hair bulbs and remarkable shape changes, respectively, thereby showing its potential in induction of hair growth.ConclusionThese results suggest that the hydrogel nanoparticle formulation developed in this study can be employed as a potential approach for the preservation of hair growth-promoting compounds, their delivery of into hair follicles, and enhancing hair growth.

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Preparation of injectable and thermoresponsive hydrogel based on penta-block copolymer with improved sol stability and mechanical properties

Cited by 42 publications

References 44 publications

Synthesis and evaluation of injectable thermosensitive penta‐block copolymer hydrogel (PNIPAAm‐PCL‐PEG‐PCL‐PNIPAAm) and star‐shaped poly(CL─CO─LA)‐b‐PEG for wound healing applications

Synthesis and evaluation of injectable thermosensitive penta‐block copolymer hydrogel (PNIPAAm‐PCL‐PEG‐PCL‐PNIPAAm) and star‐shaped poly(CL─CO─LA)‐b‐PEG for wound healing applications

Engineering folate-targeting diselenide-containing triblock copolymer as a redox-responsive shell-sheddable micelle for antitumor therapy in vivo

<p>Poly(γ-Glutamic Acid)/Chitosan Hydrogel Nanoparticles For Effective Preservation And Delivery Of Fermented Herbal Extract For Enlarging Hair Bulb And Enhancing Hair Growth</p>

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