Synthesis and Characterization of the Novel Nε-9-Fluorenylmethoxycarbonyl-l-Lysine N-Carboxy Anhydride. Synthesis of Well-Defined Linear and Branched Polypeptides

Lysine and citric acid based pegylated polymeric dendritic nano drug delivery carrier and their bioactivity evaluation

The main objective of this work is to synthesize multifunctional nanodendritic structural molecules that can effectively encapsulate hydrophilic as well as hydrophobic therapeutic agents. Four different types of fourth-generation lysine-citric acid based dendrimer have been synthesized in this work: PE-MC-Lys-CA-PEG, TMP-MC-Lys-CA-PEG, PE-MS-Lys-CA-PEG, and TMP-MS-Lys-CA-PEG. The antibacterial drug cefotaxime (CFTX) was further conjugated to these dendrimers. The dendrimer and drug-dendrimer conjugate structures were characterized with the help of FTIR,1H-NMR, and 13C-NMR spectroscopy. Zeta sizer, AFM, and HR-TEM techniques were used to investigate the particle size, surface topography, and structural characteristics of drug-dendrimer conjugates. In vitro drug release was then investigated using dialysis method. Various kinetic drug release models were examined to evaluate the type of kinetic drug release mechanism of the formulations. Cytotoxicity study revealed that the dendrimers encapsulated with CFTX exhibited 2-3% toxicity against healthy epithelial cells, indicating their safe use. Plain dendrimers show 10-15% hemolytic toxicity against red blood cells (RBC), and the toxicity was reduced to 2-3% when CFTX was conjugated to the same dendrimers. The 3rd and 4th generation synthesized drug-dendrimer conjugates exhibit a significantly effective zone of inhibition (ZOI) against both Gram-positive and Gram-negative bacteria. For Gram-positive bacteria, the lower concentration of 0.1 mg/mL showed more than 98% inhibition of drug-dendrimer conjugate samples against B. subtilis and more than 50% inhibition against S. aureus using 0.2 mg/mL, respectively. Moreover, samples with concentrations of 0.5 and 1.0 mg/mL exhibited more than 50% inhibition against S. typhimurium and E. coli, respectively.

Special Issue "State-of-the-Art Polymer Science and Technology in Greece"

Polymer science and technology is an active and continuously developing field of research and innovation in Greece [...].

pH/redox-responsive core cross-linked based prodrug micelle for enhancing micellar stability and controlling delivery of chemo drugs: An effective combination drug delivery platform for cancer therapy

Core-crosslinking of micelles (CCMs) appears to be a favorable strategy to enhance micellar stability and sustained release of the loaded drug. In this study, the DOX-conjugated pH-sensitive polymeric prodrug Methoxy Poly (ethylene oxide)-b-Poly (Aspartate-Hydrazide) (mPEG-P [Asp-(Hyd-DOX)] was created using ring-opening polymerization. To further enhance the micellar system, 3,3'-diselanediyldipropanoic acid (DSeDPA) was applied to link the hydrophobic segment via click reaction to form pH/redox-responsive CCMs. Dual anti-cancer drugs, DOX as a pro-drug and SN-38 as a targeting drug, were used to enhance inhibition. DLS confirmed that the non-cross-linked micelle (NCMs) showed a higher (96.43 nm) particle size compared to the CCMs (72.63 nm). Due to micellar shrinkage after crosslinking, CCMs displayed SN-38 drug loading (7.32 %) and encapsulation efficiency (86.23 %). The mPEG-P(Asp-Hyd) copolymer's in vitro cytotoxicity on HeLa and HaCaT cell lines found that 84.52 % of the cells are alive, and zebrafish (Danio rerio) embryos and larvae are highly biocompatible. The DOX/SN-38@CCMs had a sustained discharge profile in vitro, unlike the DOX/SN-38@NCMs. In DOX/SN-38@CCMs, HeLa cells were inhibited 50.90 % more than HaCaT (14.25 %) at the maximum drug dose (10 μg/mL). The CCMs successfully targeted and supplied DOX/SN-38 in HeLa cells rather than HaCaT cells, based on cellular uptake of 2D cell culture. CCMs, unlike NCMs, inhibit the growth of spheroids for extended periods of time due to the prolonged release of the loaded drug. Overall, CCMs are good-looking for use as regulated delivery of DOX/SN-38 in cancer cells because of all of these appealing characteristics.

Preparation and characterization of tranexamic acid modified porous starch and its application as a hemostatic agent

Effective bleeding control is essential for the reduction of traumatic deaths among civilians and military personnel, particularly for physical visceral and arteriovenous injuries. Materials with good hemostatic properties have recently attracted significant scientific attention. In this study, a novel material of tranexamic acid modified porous starch (TAMPS) was produced through esterification. The structure of the final product was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The hemostatic effect of TAMPS was preliminarily analyzed via in vitro clotting time, mouse tail amputation model and liver injury model experiments. Hemostatic effect of TAMPS was found to be significantly better than that of the positive control Quickclean. Through the exploration of related hemostatic mechanisms, TAMPS can promote coagulation via rapid fluid absorption and high erythrocyte aggregation capacity. The in vitro cytotoxicity, acute toxicity, and hemolysis tests revealed that TAMPS is safe and nontoxic and has perfect blood compatibility. Therefore, the TAMPS has a great potential for future clinical application as a rapid and multitarget hemostatic material.