Cyclopropenium-Based Biodegradable Polymers

Revisiting of Properties and Modified Polyethylenimine-Based Cancer Gene Delivery Systems

A new era of medical technology in cancer treatment is a directly specific modification of gene expression in tumor cells by nucleic acid delivery. Currently, the main challenge to achieving this goal is to find a non-toxic, safe, and effective strategy for gene transfer to cancer cells. Synthetic composites based on cationic polymers have historically been favored in bioengineering due to their ability to mimic bimolecular structures. Among them, polyethylenimines (PEIs) with superior properties such as a wide range of molecular weight and a flexible structure may propel the development of functional combinations in the biomedical and biomaterial fields. Here, in this review, we will focus on the recent progressions in the formulation optimization of PEI-based polyplex in gene delivery to treat cancer. Also, the effect of PEI's intrinsic characteristics such as structure, molecular weight, and positive charges which influence the gene delivery efficiency will be discussed.

Imaging moiety-directed co-assembly for biodegradation control with synchronous four-modal biotracking

The complexity of existing methods for biodegradation control limits the multi-functionality of biomedical materials. It is urgent to develop simple and straightforward strategies to control the biodegradation rate with precise tracking of various parameters in real-time. Here, we show an imaging moiety-directed co-assembly strategy, in which different imaging moieties bearing non-covalent interaction sites are covalently introduced into the poly (D,l-lactic acid) (PDLLA) chain as end groups, followed by alternate non-covalent interactions with polymer chains upon compression molding. This strategy takes advantage of a variety of bonding types (including CH-π, CH-F, etc.) to firmly integrate the PDLLA chains and strongly control the biodegradation rate, making the amorphous prototype degraded much slower than higher-molecular-weight counterparts, and the local inflammatory response is insignificant. On this basis, a synchronous four-modal (X-ray computed tomography + fluorescence + photoacoustics + ultrasound) imaging was achieved on the single entity in vivo, even within a millimeter-scale thick-skin tissue. These imaging signals can precisely correlate the multi parameter variation trend of material mass, volume and molecular weight, signifying that co-assembly can be utilized to develop advanced theranostic systems. SINGLE SENTENCE SUMMARY: We developed an imaging moiety-directed co-assembly strategy to control the biodegradation rate and achieve the synchronization of real-time four-modal imaging in vivo. These imaging signals can precisely correlate the multi-parameter variation trend of material mass, volume and molecular weight, which provided comprehensive biomedical information accessing both qualitatively and quantitatively.

Cationic Cyclopropenium-Based Hyper-Crosslinked Polymer Enhanced Polyethylene Oxide Composite Electrolyte for All-Solid-State Li-S Battery

The development of solid-state polymer electrolytes is an effective way to overcome the notorious shuttle effect of polysulfides in traditional liquid lithium sulfur batteries. In this paper, cationic cyclopropenium based cross-linked polymer was firstly prepared with the one pot method, and then the counter ion was replaced by TFSI⁻ anion using simple ion replacement. Cationic cyclopropenium hyper-crosslinked polymer (HP) was introduced into a polyethylene oxide (PEO) matrix with the solution casting method to prepare a composite polymer electrolyte membrane. By adding HP@TFSI to the PEO-based electrolyte, the mechanical and electrochemical properties of the solid-state lithium-sulfur batteries were significantly improved. The PEO-20%HP@TFSI electrolyte shows the highest Li⁺ ionic conductivity at 60 °C (4.0 × 10⁻⁴ S·cm⁻¹) and the highest mechanical strength. In the PEO matrix, uniform distribution of HP@TFSI inhibits crystallization and weakens the interaction between each PEO chain. Compared with pure PEO/LiTFSI electrolyte, the PEO-20%HP@TFSI electrolyte shows lower interface resistance and higher interface stability with lithium anode. The lithium sulfur battery based on the PEO-20%HP@TFSI electrolyte shows excellent electrochemical performance, high Coulombic efficiency and high cycle stability. After 500 cycles, the capacity of the lithium-sulfur battery based on PEO-20%HP@TFSI electrolytes keeps approximately 410 mAh·g⁻¹ at 1 C, the Coulomb efficiency is close to 100%, and the cycle capacity decay rate is 0.082%.

Asymmetric trisalkylamine cyclopropenium derivatives with antimicrobial activity

Cationic molecules are found in abundance as antimicrobial agents with a well-defined mechanism of action and significant therapeutic benefits. Quaternary ammonium-containing compounds are frequently employed due to their facile synthesis and tunable properties. Over time, however, bacterial resistance to these compounds has become a significant obstacle. We report here a series of asymmetric trisalkylamine cyclopropenium cationic derivatives as chemical isosteres of quaternary ammonium compounds, capable of strong antimicrobial activity and overcoming microbial resistance. These small molecules were prepared by one-pot reaction of tetrachlorocyclopropene (TCC) with unhindered secondary amines in the presence of Hünig's base. In this work we describe the synthesis, purification, and characterization of five trisamino-cyclopropenium derivatives and confirm their structures by spectral analysis and mass-spectrometry. Three of the compounds displayed considerable antimalarial activity (IC₅₀ < 0.1 µM) without demonstrating significant toxic effects in vitro (TC₅₀ > 1 µM). This class of cyclopropenium-based compounds provides an opening for the discovery of potent and non-toxic antimicrobial agents.