Elastin-like polypeptides in drug delivery (original) (raw)
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Applications of elastin-like polypeptides in drug delivery
Elastin-like polypeptides (ELPs) are biopolymers inspired by human elastin. Their lower critical solution temperature phase transition behavior and biocompatibility make them useful materials for stimulus-responsive applications in biological environments. Due to their genetically encoded design and recombinant synthesis, the sequence and size of ELPs can be exactly defined. These design parameters control the structure and function of the ELP with a precision that is unmatched by synthetic polymers. Due to these attributes, ELPs have been used extensively for drug delivery in a variety of different embodiments-as soluble macromolecular carriers, self-assembled nanoparticles, cross-linked microparticles, or thermally coacervated depots. These ELP systems have been used to deliver biologic therapeutics, radionuclides, and small molecule drugs to a variety of anatomical sites for the treatment of diseases including cancer, type 2 diabetes, osteoarthritis, and neuroinflammation.
Nanotechnological approach to the therapeutic delivery using elastin-like recombinamers
Bioconjugate Chemistry, 2015
This review discusses the use of elastin-like polymers and their recombinant version, elastinlike recombinamers, in drug-delivery systems. These macromolecules exhibit a number of interesting properties that are rarely found together in any other family of materials, especially extremely high biocompatibility, high bioactivity and functionality, complex yet fully controlled composition and stimuli responsiveness. Appropriate design of these molecules opens up a broad range of different possibilities for their use in new therapeutic platforms. The first of these described herein is the use of ELRs in singlemolecule devices as therapeutic entities on their own. Subsequently, we describe how the selfassembly properties of these materials can be exploited to create nanocarriers and, eventually, microcarriers that are able to temporally and spatially control and direct the release of their drug load. Intracellular drug-delivery devices and nanocarriers for treating cancer are among the uses described in that section. Finally, the use of ELRs as base materials for implantable drug depots, in the form of hydrogels, is discussed.
Elastin-Like Recombinamers As Smart Drug Delivery Systems
Current Drug Targets, 2018
Drug delivery systems that are able to control the release of bioactive molecules and designed to carry drugs to target sites are of particular interest for tissue therapy. Moreover, systems comprising materials that can respond to environmental stimuli and promote self-assembly and higher order supramolecular organization are especially useful in the biomedical field. Suitable biomaterials for this purpose include elastin-like recombinamers (ELRs), a class of proteinaceous polymers bioinspired by natural elastin and designed using recombinant technologies. The self-assembly and thermoresponsive behaviour of these systems, along with their biodegradability, biocompatibility and well-defined composition as a result of their tailor-made design, make them particularly attractive for drug delivery. This review brings together information concerning ELR-based delivery systems that allow targeted delivery, especially ELR-drug recombinant fusion constructs, ELR-drug systems chemically bioconjugated in their monomeric and soluble forms, and drug encapsulation by nanoparticle-forming ELRs. Subsequently, we will focus on those drug carriers in which smart release is triggered by pH or temperature with a particular focus on cancer treatments in which both enhanced permeability retention (EPR) and local mild hyperthermia cause ELRs to become aggregated or form well-defined nanoparticles at the site of action. Systems for controlled drug release based on depots and hydrogels that act as both a support and reservoir in which drugs can be stored will be described, and their applications in drug delivery discussed. Finally, smart drug-delivery systems not based on ELRs, including those comprising proteins, synthetic polymers and non-polymeric systems, will also be briefly discussed.
Genetically Encoded Elastin‐Like Polypeptides for Drug Delivery
Advanced Healthcare Materials, 2021
Elastin-like polypeptides (ELPs) are thermally responsive biopolymers that consist of a repeated amino acid motif derived from human tropoelastin. These peptides exhibit temperature-dependent phase behavior that can be harnessed to produce stimuli-responsive biomaterials, such as nanoparticles or injectable drug delivery depots. As ELPs are genetically encoded, the properties of ELP-based biomaterials can be controlled with a precision that is unattainable with synthetic polymers. Unique ELP architectures, such as spherical or rod-like micelles or injectable coacervates, can be designed by manipulating the ELP amino acid sequence and length. ELPs can be loaded with drugs to create controlled, intelligent drug delivery systems. ELPs are biodegradable, nonimmunogenic, and tolerant of therapeutic additives. These qualities make ELPs exquisitely well-suited to address current challenges in drug delivery and have spurred the development of ELP-based therapeutics to treat diseases-such as cancer and diabetes-and to promote wound healing. This review focuses on the use of ELPs in drug delivery systems.
Author's personal copy Drug delivery to solid tumors by elastin-like polypeptides
Thermally responsive elastin-like polypeptides (ELPs) are a promising class of recombinant biopolymers for the delivery of drugs and imaging agents to solid tumors via systemic or local administration. This article reviews four applications of ELPs to drug delivery, with each delivery mechanism designed to best exploit the relationship between the characteristic transition temperature (T t ) of the ELP and body temperature (T b ). First, when T t ≫ T b , small hydrophobic drugs can be conjugated to the C-terminus of the ELP to impart the amphiphilicity needed to mediate the self-assembly of nanoparticles. These systemically delivered ELP-drug nanoparticles preferentially localize to the tumor site via the EPR effect, resulting in reduced toxicity and enhanced treatment efficacy. The remaining three approaches take direct advantage of the thermal responsiveness of ELPs. In the second strategy, where T b b T t b 42°C, an ELP-drug conjugate can be injected in conjunction with external application of mild hyperthermia to the tumor to induce ELP coacervation and an increase in concentration within the tumor vasculature. The third approach utilizes hydrophilichydrophobic ELP block copolymers that have been designed to assemble into nanoparticles in response to hyperthermai due to the independent thermal transition of the hydrophobic block, thus resulting in multivalent ligand display of a ligand for spatially enhanced vascular targeting. In the final strategy, ELPs with T t b T b are conjugated with radiotherapeutics, injtect intioa tumor where they undergo coacervation to form an injectable drug depot for intratumoral delivery. These injectable coacervate ELP-radionuclide depots display a long residence in the tumor and result in inhibition of tumor growth.
Drug delivery to solid tumors by elastin-like polypeptides
2010
Thermally responsive elastin-like polypeptides (ELPs) are a promising class of recombinant biopolymers for the delivery of drugs and imaging agents to solid tumors via systemic or local administration. This article reviews four applications of ELPs to drug delivery, with each delivery mechanism designed to best exploit the relationship between the characteristic transition temperature (T t ) of the ELP and body temperature (T b ). First, when T t >> T b , small hydrophobic drugs can be conjugated to the C-terminus of the ELP to impart the amphiphilicity needed to mediate the self-assembly of nanoparticles. These systemically delivered ELP-drug nanoparticles preferentially localize to the tumor site via the EPR effect, resulting in reduced toxicity and enhanced treatment efficacy. The remaining three approaches take direct advantage of the thermal responsiveness of ELPs. In the second strategy, where T b < T t < 42 °C, an ELP-drug conjugate can be injected in conjunction with external application of mild hyperthermia to the tumor to induce ELP coacervation and an increase in concentration within the tumor vasculature. The third approach utilizes hydrophilic-hydrophobic ELP block copolymers that have been designed to assemble into nanoparticles in response to hyperthermai due to the independent thermal transition of the hydrophobic block, thus resulting in multivalent ligand display of a ligand for spatially enhanced vascular targeting. In the final strategy, ELPs with T t < T b are conjugated with radiotherapeutics, injtect intioa tumor where they undergo coacervation to form an injectable drug depot for intratumoral delivery. These injectable coacervate ELP-radionuclide depots display a long residence in the tumor and result in inhibition of tumor growth.
International journal of Pharmacy and Pharmaceutical Sciences, 2014
Introduction: Among the several new strategies explored today to avoid the side effects in cancer chemotherapy. The concept of polymer-drug conjugates has shown considerable promise. In this context, genetically engineered long elastin like polypeptides (ELPs) have been examined recently as drug carriers. These ELPs, however, have certain limitations. Objective: It is our hypothesis that short synthetic ELPs can also be used as drug carriers so as to overcome these limitations. The purpose of this investigation was, therefore, to synthesize, characterize and evaluate a thermally responsive short ELP-Doxorubicin conjugate for targeted delivery. Methods: The ELP-Doxorubicin conjugate of molecular weight 1280 Da was synthesized and characterized by ESI-MS, FTIR and NMR studies. Turbidimetry, differential scanning calorimetry (DSC) and circular dichorism (CD) studies were carried out to evaluate its structural transition behavior. Cellular uptake and intracellular localization studies of the conjugate and the free drug were carried out by flow cytometry and confocal fluorescence microscopy, respectively. In vitro cytotoxicity of the conjugate was evaluated by the MTT assay method and compared with that of the free drug. Results: The results reveal that the short ELP synthesized exhibits structural transition behavior similar to naturally occurring long ELPs and delivers more drug molecules to intracellular space compared to the free drug. This structural transition behavior can also be exploited for targeting drugs to solid tumors using hyperthermia. Conclusion: As hypothesized our investigations clearly demonstrate that short thermally responsive ELPs are good carrier for targeting anticancer drugs to the intracellular space.