In Vitro and in Vivo Studies of pH-Sensitive GHK-Cu-Incorporated Polyaspartic and Polyacrylic Acid Superabsorbent Polymer

Superabsorbent hydrogels based on natural polysaccharides: Classification, synthesis, physicochemical properties, and agronomic efficacy under abiotic stress conditions: A review

Superabsorbent polymers (SAPs) are a class of polymers that have attracted tremendous interest due to their multifunctional properties and wide range of applications. The importance of this class of polymers is highlighted by the large number of publications, including articles and patents, dealing with the use of SAPs for various applications. Within this framework, this review provides an overview of SAPs and highlights various key aspects, such as their history, classification, and preparation methods, including those related to chemically or physically cross-linked networks, as well as key factors affecting their performance in terms of water absorption and storage. This review also examines the potential use of polysaccharides-based SAPs in agriculture as soil conditioners or slow-release fertilizers. The basic aspects of SAPs, and methods of chemical modification of polysaccharides are presented and guidelines for the preparation of hydrogels are given. The water retention and swelling mechanisms are discussed in light of some mathematical empirical models. The nutrient slow-release kinetics of nutrient-rich SAPs are also examined on the basic of commonly used mathematical models. Some examples illustrating the advantages of using SAPs in agriculture as soil conditioners and agrochemical carriers to improve crop growth and productivity are presented and discussed. This review also attempts to provide an overview of the role of SAPs in mitigating the adverse effects of various abiotic stresses, such as heavy metals, salinity, and drought, and outlines future trends and prospects.

Polyaspartic acid, 2-acrylamido-2-Methyl propane sulfonic acid and sodium alginate based biocompatible stimuli responsive polymer gel for controlled release of GHK-Cu peptide for wound healing

Stimuli responsive polymer based on Polyaspartic acid, 2-Acrylamido-2-methylpropane sulfonic acid and sodium alginate (NaAlg) were synthesized using two cross-linkers Ethylene glycol dimethacrylate (EGDMA) and TMPTA (Trimethylolpropane triacrylate). The polymers were standardized and optimized to obtain a polymer with maximum swelling in distilled water, saline, glucose and solutions of varying pH. The synthesized polymer swelled well in distilled water, glucose solution and acidic- alkaline medium. The biocompatibility of the polymer was evaluated for blood compatibility and protein adsorption. The polymer with maximum swelling property was used for peptide release studies. The polymer was further used to study the peptide encapsulation and release efficiency of the polymeric material which was confirmed by FTIR, Scanning Emission Microscope and EDX. The encapsulation efficiency of the polymer for encapsulating (glycyl-l-histidyl-l-lysine-copper) GHK-Cu was observed to be 55.26% and peptide release of 51.84% was observed for Ethylene glycol dimethacrylate based polymer after 24 h whereas for Trimethylolpropane triacrylate based polymer the encapsulation efficiency was observed to be 49.6% and release was 39.01%. The EGDMA based polymer was further examined under in vivo studies in order to evaluate the efficiency of the synthesized polymer. The in vivo studies include wound closure, histopathological analysis, biochemical and toxicity assay. The material has shown promising results for both in vivo and in vitro studies.

Poly(aspartic acid) in Biomedical Applications: From Polymerization, Modification, Properties, Degradation, and Biocompatibility to Applications

Poly(aspartic acid) (PASP) is an anionic polypeptide that is a highly versatile, biocompatible, and biodegradable polymer that fulfils key requirements for use in a wide variety of biomedical applications. The derivatives of PASP can be readily tailored via the amine-reactive precursor, poly(succinimide) (PSI), which opens up a large window of opportunity for the design and development of novel biomaterials. PASP also has a strong affinity with calcium ions, resulting in complexation, which has been exploited for bone targeting and biomineralization. In addition, recent studies have further verified the biocompatibility and biodegradability of PASP-based polymers, which is attributed to their protein-like structure. In light of growing interest in PASP and its derivatives, this paper presents a comprehensive review on their synthesis, characterization, modification, biodegradation, biocompatibility, and applications in biomedical areas.

Ternary Cu(II) Complex with GHK Peptide and Cis-Urocanic Acid as a Potential Physiologically Functional Copper Chelate

The tripeptide NH₂–Gly–His–Lys–COOH (GHK), cis-urocanic acid (cis-UCA) and Cu(II) ions are physiological constituents of the human body and they co-occur (e.g., in the skin and the plasma). While GHK is known as Cu(II)-binding molecule, we found that urocanic acid also coordinates Cu(II) ions. Furthermore, both ligands create ternary Cu(II) complex being probably physiologically functional species. Regarding the natural concentrations of the studied molecules in some human tissues, together with the affinities reported here, we conclude that the ternary complex [GHK][Cu(II)][cis-urocanic acid] may be partly responsible for biological effects of GHK and urocanic acid described in the literature.