Microdomains in block copolymers and multiplets in ionomers: parallels in behavior

Nyrkova, I. A.; Khokhlov, Alexei R.; Doi, Masao

doi:10.1021/ma00066a019

Cited by 161 publications

(179 citation statements)

References 21 publications

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“…At higher polymer concentrations, the block copolymers form gels with physically entangled networks. Such physical gelation has been observed previously with gels of multiblock copolymers in selective solvents (38)(39)(40)(41).…”

Section: Resultssupporting

confidence: 78%

Design of an injectable synthetic and biodegradable surgical biomaterial

Zawaneh¹,

Singh

Padera

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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We report the design of an injectable synthetic and biodegradable polymeric biomaterial comprised of polyethylene glycol and a polycarbonate of dihydroxyacetone (MPEG-pDHA). MPEG-pDHA is a thixotropic physically cross-linked hydrogel, displays rapid chain relaxation, is easily extruded through narrow-gauge needles, biodegrades into inert products, and is well tolerated by soft tissues. We demonstrate the clinical utility of MPEG-pDHA in the prevention of seroma, a common postoperative complication following ablative and reconstructive surgeries, in an animal model of radical breast mastectomy. This polymer holds significant promise for clinical applicability in a host of surgical procedures ranging from cosmetic surgery to cancer resection.hydrogel | seroma prevention | dihydroxyacetone | surgical biomaterial P olymeric biomaterials have contributed significantly to the advancement of medical and surgical practice over the past few decades. Their macromolecular structure can be tailored to provide the appropriate combination of chemical, physical, and biological properties necessary for a range of medical and surgical applications. The rational design of polymeric biomaterials has impacted many fields, including drug and gene delivery, orthopedics, tissue engineering, ophthalmology, and general surgery (1-3). The work reported herein focuses on the development of an injectable surgical biomaterial. Its potential impact is demonstrated in the prevention of postoperative seroma.A seroma is an abnormal collection of serous fluid within the tissues of the body, akin to an internal blister. Seroma formation is a common postoperative complication particularly following ablative and reconstructive surgeries. Surgeries that require extensive tissue dissection and create large empty spaces can disrupt normal lymphatic flow. Subsequently, transduate fluid collects in these poorly drained "dead spaces," resulting in formation of a seroma (4, 5). Seromas can lead to significant patient morbidity, such as infection, decreased limb mobility, and reoperation (4, 6, 7). Seroma formation rates range from 9.1% to 81%, depending on the nature of the surgical procedure (6,(8)(9)(10)(11)(12)(13). Notably, modified radical mastectomies lead to seroma formation rates ranging from 15% to 38.6%, and radical mastectomies report a rate as high as 52% (7,(14)(15)(16)(17). In current clinical practice, silicone surgical drains are placed in the wound bed through separate stab incisions to collect transudate fluid, but they can be a significant source of pain and discomfort to patients, especially upon their removal up to several weeks after the initial surgical procedure. Furthermore, they can increase the risk of infection at the surgical site.Several approaches to reduce seroma formation have been investigated. Surgical techniques, such as collapsing the seroma cavity with sutures, do not consistently and adequately eliminate seroma formation (16,18,19). Other methods, such as sclerotherapy (20, 21), compression dressings (22), and biolog...

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Section: Resultssupporting

confidence: 78%

Design of an injectable synthetic and biodegradable surgical biomaterial

Zawaneh¹,

Singh

Padera

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…Due to enormous interfacial tension these systems are in a thermodynamic state close to the super-strong segregation limit (SSSL). [112] Under these conditions, a sequence of shape transitions from spherical ® cylindrical ® lamellar is possible. Such transitions can be induced by increasing the ionic strength of the solution or by increasing the relative length of the core block.…”

Section: Micellesmentioning

confidence: 99%

Amphiphilic Block Copolymers in Structure-Controlled Nanomaterial Hybrids

Förster¹,

1998

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Amphiphilic block copolymers (ABCs) are important in interface and particle stabilization. Following consideration of the various methods of synthesis of ABCs, mesophases and micelles of block copolymers and the solubilization and adhesion of ABCs are considered. The Figure shows micelles formed by a polystyrene‐poly(vinylpyridine) copolymer. Nanoparticles and ABC/nanoparticle hybrid systems are also reviewed.

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“…20 In the latter case, the insoluble blocks of multiblock copolymer form multiplet-like domains bridged by soluble blocks. Formation of polydispersed clusters takes place at lower copolymer concentrations, whereas gel formation is favored at higher concentrations because of the growth of randomly multiconnected clusters linked together by insoluble domains.…”

Section: Rheological Propertiesmentioning

confidence: 99%

Structure formation in injectable poly(lactide‐co‐glycolide) depots. II. Nature of the gel

et al. 2004

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The benzyl benzoate solutions of poly(D,L-lactide-co-glycolide), a random oriented synthesized copolymer with L/G ratio of 50:50, have been shown to form gels during aging and upon injection into buffer or water. The gelation properties influence drug release kinetics for these injectable, depot-forming solutions. In this article, we report on the mechanism of gelation. We find that only polymers that have a certain average block length of glycolide units form gels during aging as well as depots upon in vitro. Thus, gel formation is likely due to the formation of ordered solvated aggregates of blocky glycolide units. Rheometry, differential scanning calorimetry, and nuclear magnetic resonance were used to investigate the gelation kinetics and the polymer molecular parameters. Of all the polymers used, poly(lactide-coglycolide)s with glycolide average block length <2.9 did not show any gelation behavior. The details of the gelation process are also solvent dependent.

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Microdomains in block copolymers and multiplets in ionomers: parallels in behavior

Cited by 161 publications

References 21 publications

Design of an injectable synthetic and biodegradable surgical biomaterial

Design of an injectable synthetic and biodegradable surgical biomaterial

Amphiphilic Block Copolymers in Structure-Controlled Nanomaterial Hybrids

Structure formation in injectable poly(lactide‐co‐glycolide) depots. II. Nature of the gel

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