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Biocomposites and Nanocomposites
Published in Amit Sachdeva, Pramod Kumar Singh, Hee Woo Rhee, Composite Materials, 2021
C. H. Lee, S. H. Lee, F. N. M. Padzil, Z. M. A. Ainun, M. N. F. Norrrahim, K. L. Chin
Proteins, also called polypeptides, are formed of one or more long, linear chains of amino-acid residues connected by peptide bonds. Different proteins have different sequences of amino acids. A short polypeptide may contain 20 to 30 residues; these are commonly known as peptides or oligopeptides. Proteins also contain non-peptide groups that are called prosthetic groups or cofactors. The main function of proteins is to be molecular transporters. Proteins are essential parts of organisms and participate in all processes within cells. There are several purification methods for proteins: ultrafiltration (Jang, Liceaga, and Yoon 2016), ultracentrifugation, precipitation, gel filtration chromatography (Agrawal et al., 2016), electrophoresis, and chromatography (Jin et al. 2016). One study carried out by Wang et al. (2017a) gradually isolated microalgal components in order to obtain lipid-rich, protein-rich, and carbohydrate-rich components using the pyrolysis mechanism of the microalgae (Wang et al. 2017b). The three components of lipid, protein, and carbohydrate have specific pyrolysis pathways as shown in Figure 2.4.
Arsenals of Pharmacotherapeutically Active Proteins and Peptides: Old Wine in a New Bottle
Published in Debarshi Kar Mahapatra, Swati Gokul Talele, Tatiana G. Volova, A. K. Haghi, Biologically Active Natural Products, 2020
On the basis of number of amino acids present, peptides can be classified as: Dipeptide which contains two amino acid residues.Tripeptide which contains three amino acid residues.Tetrapeptide which contains four amino acid residues.Oligopeptides which contain less than 10 amino acid residues.Polypeptides which contain 50 or less than 50 amino acid residues.
Synthetic Polymer-Drug Conjugates for Human Therapy
Published in Vladimir Torchilin, Mansoor M Amiji, Handbook of Materials for Nanomedicine, 2011
As mentioned earlier there were problems with reproducible synthesis and rather complex structure of the conjugates targeted with large proteins or glycoproteins. Moreover, potential immunogenicity of the proteins also persists. This is why oligopeptides recognized as an active sequence responsible for interaction of glycoproteins with their receptors were selected and their potential as targeting moiety was tested. Suitable oligopeptides were also designed by combinatorial methods such as phage display139 or they were discovered as binding domains of natural proteins, such as proteins of extracellular matrix like fibronectin or laminin. Synthetic oligopeptides can be produced in much larger quantities and at much lower costs than the monoclonal antibodies. Covalent attachment of a short synthetic oligopeptide to a polymer carrier can be accomplished using standard methods of peptide and polymer chemistry yielding a well-defined product. In principle, the conjugates can be directed straight to the receptors of malignant cells or they can be aimed at normal cells of tumor endothelium.
PEG-SH-GNPs-SAPNS@miR-29a delivery system promotes neural regeneration and recovery of motor function after spinal cord injury
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Junming Wan, Hanzhong Liu, Jiachun Li, Yuqing Zeng, Haiyong Ren, Yanqing Hu
In recent years, Self-assembled nano-polypeptide has become one of the most attractive nanomaterials in the fields of tissue engineering and biomaterials [29, 30]. It has been found that bioactive fragments can be directly linked to the C-terminal of self-assembled oligopeptide molecules by the solid-phase synthesis method. The polypeptide has special biological activity and triggers molecular self-assembly under certain conditions [31–33]. The self-assembled polypeptide hydrogel has several advantages: (1) elastic modulus similar to the spinal cord; (2) no immune rejection; (3) favorable for stem cells adhesion and proliferation [34–36]. Previous studies showed that self-assembled peptides could inhibit inflammation, and promote the proliferation and differentiation of NSCs. In this research, we carried out in vitro and in vivo experimental studies on PEG-SH-GNPs-SAPNS@miR-29a delivery system. The results demonstrated that PEG-SH-GNPs-SAPNS@miR-29a delivery system could significantly promote the endogenous axonal regeneration in the injury site of the spinal cord. We found no potential off-target effects of miR29a.