Elastin-like polypeptide

Elastin-like polypeptides have been explored as hydrogels due to their capacity for self-assembly and phase transition behavior they also mimic many features of the extracellular matrk and have the potential to guide the migration, growth and organization of 

The temperature sensitivity of ELPs may be exploited in tissue engineering for those applications that may benefit from biomaterial formulations that are injectable and may be tri ered in some way to form a solid matrix after defect filling. The inherent thermal transition properties of ELPs provide a natural tri er for coacervation, and reversibility of the phase transition enables recovery of ELPs from applications that desire a scaffold-free outcome. 

Amiram et al. (2013) developed an entirety geneticalty encoded peptide delivery system—protease operated depots (PODs)—by the 

ELPs were explored as potential proteol5dic stimuli-responsive systems to control the release of model protein (Xia et al., 2011). The advantage of the proposed system is that The ELPs-based matrices can be conveniently modified by insertion of sequences mimicking those of other natural proteins. In this way, functional domains can be easily incorporated to increase the biological properties of the hydrogels improving the features of the final product. 

A particular kind of materials are the silk-elastin-like protein polymers (SELPs), consisting of the repeating units of silk and elastin blocks, which combine a set of outstanding physical and biological properties of silk and elastin. SELPs can undergo tunable 

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Keywords Elastin Elastin-like polypeptides Elastomeric polypeptides Resilin Resilin-like polypeptides... 

The first elastomeric protein is elastin, this structural protein is one of the main components of the extracellular matrix, which provides stmctural integrity to the tissues and organs of the body. This highly crosslinked and therefore insoluble protein is the essential element of elastic fibers, which induce elasticity to tissue of lung, skin, and arteries. In these fibers, elastin forms the internal core, which is interspersed with microfibrils [1,2]. Not only this biopolymer but also its precursor material, tropoelastin, have inspired materials scientists for many years. The most interesting characteristic of the precursor is its ability to self-assemble under physiological conditions, thereby demonstrating a lower critical solution temperature (LCST) behavior. This specific property has led to the development of a new class of synthetic polypeptides that mimic elastin in its composition and are therefore also known as elastin-like polypeptides (ELPs). 

This chapter will discuss the basic aspects of elastin and resilin and will address their biological role, biochemical processing, and properties. The materials inspired by elastin and resilin, such as elastin-like polypeptides and resilin-like polypeptides, and applications thereof, will also be covered. 

Elastin-like polypeptide block copolymer ELP(ViAaG7-n] I ELPBfs-nl... 

Wu WY, Fong BA, Gilles AG, Wood DW (2009) Recombinant protein purification by selfcleaving elastin-like polypeptide fusion tag. Curr Protoc Prot Sci 26.4 21-18... 

Miao M, Cirulis JT, Lee S et al (2005) Structural determinants of cross- linking and hydrophobic domains for self-assembly of elastin-like polypeptides. Biochemistry 44 14367-14375... 

Betre H, Ong SR, Guilak F et al (2006) Chondrocytic differentiation of human adipose-derived adult stem cells in elastin-like polypeptide. Biomaterials 27 91-99... 

Nettles DL, Chilkoti A, Setton LA (2010) Applications of elastin-like polypeptides in tissue engineering. Adv Drug Deliv Rev 62 1479-1485... 

Nettles DL, Haider MA, Chilkoti A et al (2010) Neural network analysis identifies scaffold properties necessary for in vitro chondrogenesis in elastin-like polypeptide biopolymer scaffolds. Tissue Eng A 16 11-20... 

Dreher MR, Raucher D, Balu N et al (2003) Evaluation of an elastin-like polypeptide-doxorubicin conjugate for cancer therapy. J Control Release 91 31 3... 

Bidwell GL, Fokt 1, Priebe W et al (2007) Development of elastin-like polypeptide for thermally targeted delivery of doxorubicin. Biochem Pharmacol 73 620-631... 

Betre, H., Setton, L. A., Meyer, D. E., and Chilkoti, A. (2002). Characterization of a genetically engineered elastin-like polypeptide for cartilaginous tissue repair. Biomacromolecules 3, 910-916. 

The azo-modified, elastin-like polypeptide XIV illustrated in Scheme 9 exhibits a so-called inverse temperature transition" that is, the compound gives cross-linked gels that remain swollen in water at temperature below 25 °C but deswell and contract upon a rise of temperature. The trans-cis photoisomerization of the azo units, obtained through alternating irradiation at 350 and 450 nm, permits photomodulation of the inverse temperature transition.[S9] The result indicates that attachment of a small proportion of azobenzene chromophores is sufficient to render inverse temperature transition of elastin-like polypeptides photoresponsive, and provides a route to protein-based polymeric materials capable of photomechanical transduction. 

Fig. 1 Nanopatterned surface bearing thermoresponsive elastin-like polypeptides (ELP) allowing reversible capture and release of fusion proteins left ELP switch off center ELP switch on right AFM image of a 10 x 9 ELP dot array in PBS at room temperature. Reprinted, with permission, from [32]. Copyright (2004) American Chemical Society...

Figure 3. Applications of elastin and elastin-like polypeptides (ELPs).

Meyer DE, Chilkoti A. Genetically encoded synthesis of protein-based polymers with precisely specified molecular weight and sequence by recursive directional ligation examples from the elastin-like polypeptide system. Biomacromolecules 2002 3 357-367. 

Meyer DE, Kong GA, Dewhirst MW, Zalutsky MR, Chilkoti A. Targeting a genetically engineered elastin-like polypeptide to solid tumors by local hyperthermia. Cancer Res 2001 61 1548-1554. 

The principal mechanism of temperature-sensitive polymers is the sharp transition from coil to globule in water on heating, indicating a change from a hydrophilic state (coil) below the lower critical solution temperature (LCST) to a hydrophobic state (globule) above the LCST. Representative temperature-sensitive polymers include A -isopropylacrylamide (NIPAAm), its copolymers (LCST 30-50°C) [108, 124-127], polyester block copolymers (20-100°Q [97, 128], and elastin-like polypeptides (27-40°C) [129-131]. To achieve both spatial and temporal control in conjunction with local temperature increases (2-5°C), the LCST of a given polymer can be tailored through its comonomer composition, hydrophilic-hydrophobic balance, stereochemistry [125-127,132], and the addition of salts and surfactants [133]. These thermosensitive polymers with controlled LCSTs (around body temperature) can be applied to specific applications (e.g., tumor treatment). 

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