Synthesis and aggregational behavior of acidic proteinoid

Abstract

Polypeptide‐based acidic proteinoid containing L‐glutamic acid and L‐aspartic acid in excess and five other neutral and basic amino acids in minor proportions have been synthesized and found that it forms organized aggregates in an aqueous solution. The proteinoid aggregate has been characterized using 13C‐NMR, IR, and fluorescence spectroscopic techniques. The c.m.c. of the proteinoid has been determined by conductometric and pH metric methods. The aggregation studies were carried out at different temperatures and varying ionic strengths of the medium. The phase transition of the proteinoid aggregate has been determined using the fluorescence absorbance method. The aggregation behavior is shown to be dependent on the pH of the solution. This was also supported by conductivity measurements. Using methylene blue as a model drug, the drug delivery property of the proteinoid micelles were studied in acidic (pH 4.5) and neutral (pH 7.4) mediums. Using biphasic model thermochemical parameters, ΔG, ΔH, ΔS, and ΔCp have been evaluated. © 1996 John Wiley & Sons, Inc.

Proteinoid/hydroxyapatite hybrid microsphere composites

“…Figure 7 reflects the characteristic absorption bands of pure HA by showing a weak characteristic O‐H stretching band at about 3570 cm −1 and prominent phosphate bands at about 1034 cm −1 for v3 PO4 −3 , at around 1095 cm −1 for v1 PO4 −3 , and at 565 and 602 cm −1 for v4 PO4 −3 mode 15. Moreover, the spectrum of pure proteinoids shown in Figure 7 reflected the characteristic absorption bands of amide I at 1716 cm −1 , amide II at 1540 cm −1 , O‐H bending vibrations at 1395 cm −1 , C‐N stretching vibration at 1167, 1215, and 1259 cm −1 , and N‐H at 3393 and 650–900 cm −1 16…”

“…FTIR spectra of the synthesized proteinoids/HA hybrid microsphere composite (sample 21) demonstrated the presence of proteinoids by showing amide I (CO stretching) and amide II bands at around 1611 cm −1 and 1589 cm −1 , C‐N stretching at 1038, 1097, and 1155 cm −1 , and‐NH‐ at 3206 and 650–900 cm −1 16. Moreover, it demonstrated the presence of HA by showing the O‐H stretching band at 3575 cm −1 , v3 PO4 −3 at 1027 cm −1 , v1 PO4 −3 at 1101 cm −1 , and v4 PO4 −3 at 571 and 611 cm −1 .…”

Antimicrobial Proteinoid Nanostructures via Thermal Condensation of L-Glutamic Acid and L-Tyrosine

“…This feature is attributed to their chemical composition, since they contain both hydrophobic and hydrophilic regions depending on the sidechain of the amino acid precursors. The amphiphilic nature of proteinoids, resembling that of phospholipids in biological membranes, facilitates their aggregation into capsule-like structures [ 15 , 37 ]. Figure 2 shows the STEM images in bright ( Figure 2 a) and high-angle annular dark ( Figure 2 b) field of the GluTyr 1:1 product.…”

Engineered Doxorubicin Delivery System Using Proteinoid-Poly (L-Lactic Acid) Polymeric Nanoparticles of Narrow Size Distribution and High Molecular Weight for Cancer Treatment

“…All the polymers were produced via a simple thermal condensation reaction which utilizes the carboxylate and amine groups of an amino acid side chain or those at the α-position [32]. To obtain a product with good yield by a thermal condensation reaction, anhydrous conditions and inert atmosphere are required [33]. Lysine plays the main role in this process.…”