Cyclopropenimine-Mediated CO Activation for the Synthesis of Polyurethanes and Small-Molecule Carbonates and Carbamates.

Carbon dioxide (CO) is an abundant C1 feedstock with tremendous potential to produce versatile building blocks in synthetic applications. Given the adverse impact of CO on the atmosphere, it is of paramount importance to devise strategies for upcycling it into useful materials, such as polymers and fine chemicals. To activate such stable molecule, superbases offer viable modes of binding to CO.

Ring-Opening Polymerization of Cyclic Esters and Carbonates with (Thio)urea/Cyclopropenimine Organocatalytic Systems.

Organocatalyzed ring-opening polymerization is a powerful tool for the synthesis of a variety of functional, readily degradable polyesters and polycarbonates. We report the use of (thio)ureas in combination with cyclopropenimine bases as a unique catalyst for the polymerization of cyclic esters and carbonates with a large span of reactivities. Methodologies of exceptionally effective and selective cocatalyst combinations were devised to produce polyesters and polycarbonates with narrow dispersities ( = 1.

pH-Responsive Polymeric Micelle Dynamic Complexes for Selective Killing of .

, the world's most common chronic infection-causing pathogen, is responsible for causing gastric ulcers, the fourth-leading cause of cancer-related death globally in 2020. In recent years, the effectiveness of the current treatment regimen (two antibiotics and one proton pump inhibitor) has often been plagued with problems such as resistance and the undesired elimination of commensal bacteria. Herein, we report the synthesis of block and random copolycarbonates, functionalized with cationic guanidinium and anionic acetate functional groups, aimed at selectively killing in the acidic environment of the stomach, while remaining nontoxic to the commensal bacteria in the gut.

Artificial intelligence driven design of catalysts and materials for ring opening polymerization using a domain-specific language.

Advances in machine learning (ML) and automated experimentation are poised to vastly accelerate research in polymer science. Data representation is a critical aspect for enabling ML integration in research workflows, yet many data models impose significant rigidity making it difficult to accommodate a broad array of experiment and data types found in polymer science. This inflexibility presents a significant barrier for researchers to leverage their historical data in ML development.

Nanocomplexes of Biodegradable Anticancer Macromolecules: Prolonged Plasma Half-Life, Reduced Toxicity, and Increased Tumor Targeting.

Anticancer drug resistance is a large contributing factor to the global mortality rate of cancer patients. Anticancer macromolecules such as polymers have been recently reported to overcome this issue. Anticancer macromolecules have unselective toxicity because they are highly positively charged.

Simple and Efficient Synthesis of Functionalized Cyclic Carbonate Monomers Using Carbon Dioxide.

Aliphatic polycarbonates represent an important class of materials with diverse applications ranging from battery electrolytes, polyurethane intermediates, and materials for biomedical applications. These materials can be produced via the ring-opening polymerization (ROP) of six- to eight-membered cyclic carbonates derived from precursor 1,3- and 1,5-diols. These diols can contain a range of functional groups depending on the desired thermal, mechanical, and solution properties.

A Cation-Dependent Dual Activation Motif for Anionic Ring-Opening Polymerization of Cyclic Esters.

A new organocatalyst for the ring-opening polymerization of lactones has been identified. Under the tested conditions, the anions of 2,2'-bisindole promote fast, living polymerizations (as short as 10 ms) which are selective for chain elongation over transesterification (Đ ≤ 1.1).

Elucidating the anticancer activities of guanidinium-functionalized amphiphilic random copolymers by varying the structure and composition in the hydrophobic monomer.

Use of traditional anticancer chemotherapeutics has been hindered by the multifactorial nature of multi-drug resistance (MDR) development and metastasis. Recently, cationic polycarbonates were reported as novel unconventional anticancer agents that mitigated MDR and inhibited metastasis. The aim of this study is to explore structure-anticancer activity relationship.

Effects of Hydrophobicity on Antimicrobial Activity, Selectivity, and Functional Mechanism of Guanidinium-Functionalized Polymers.

In this study, a series of guanidinium-functionalized polycarbonate random co-polymers is prepared from organocatalytic ring-opening polymerization to investigate the effect of the hydrophobic side chain (ethyl, propyl, isopropyl, benzyl, and hexyl) on their antimicrobial activity and selectivity. Although the polymers exhibit similar minimum inhibitory concentrations, the more hydrophobic polymers exhibit a faster rate of bacteria elimination. At higher percentage content (20 mol%), polymers with more hydrophobic side chains suffer from poor selectivity due to their high hemolytic activity.

Cationic polymer synergizing with chemotherapeutics and re-purposing antibiotics against cancer cells.

Chemotherapy is one of the most effective treatments for cancer. However, toxicity and the development of drug resistance have become the major hurdles to the commonly used chemotherapeutics such as doxorubicin and paclitaxel. Antibiotics have also been used as anti-cancer drugs due to their anti-proliferative and cytotoxic effects.

Selective Chemical Upcycling of Mixed Plastics Guided by a Thermally Stable Organocatalyst.

Chemical recycling of plastic waste represents a greener alternative to landfill and incineration, and potentially offers a solution to the environmental consequences of increased plastic waste. Most plastics that are widely used today are designed for durability, hence currently available depolymerisation methods typically require harsh conditions and when applied to blended and mixed plastic feeds generate a mixture of products. Herein, we demonstrate that the energetic differences for the glycolysis of BPA-PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enables the selective and sequential depolymerisation of these two commonly employed polymers.

Biodegradable Cationic Polycarbonates as Vaccine Adjuvants.

In this study, biodegradable cationic polycarbonate and polylactide block copolymers were synthesized and successfully used as novel vaccine adjuvants to provide enhanced anticancer immunity. The polymers formed nanoparticles with the model vaccine, ovalbumin (OVA), and the immunostimulant toll-like receptor 3 agonist poly(I:C) (a synthetic analog of the double-stranded RNA). Higher uptake of poly(I:C) by the bone marrow-derived dendritic cells and macrophages and OVA by dendritic cells was observed when delivered using the polymer adjuvant.

Carboxylic acid-functionalized polycarbonates as bone cement additives for enhanced and sustained release of antibiotics.

Despite the good clinical outcomes of total joint replacements, prosthetic joint infections still remain a significant cause of implant failure. Primary prophylaxis is key to stemming this burgeoning problem and its associated complications. In this study, a series of bone cement formulations with enhanced antibacterial performance have been developed through the addition of carboxylic acid-functionalized polycarbonate block copolymers to commercially available bone cement.

The effect of solvent quality on pathway-dependent solution-state self-assembly of an amphiphilic diblock copolymer.

The cholesterol-functionalized polycarbonate-based diblock copolymer, PEG--P(MTC-Chol), forms pathway-dependent nanostructures via dialysis-based solvent exchange. The initial organic solvent that dissolves or disperses the polymer dictates a self-assembly pathway. Depending upon the initial solvent, nanostructures of disk-like micelles, exhibiting asymmetric growth and hierarchical features, are accessible from a single amphiphilic precursor.

A Macromolecule Reversing Antibiotic Resistance Phenotype and Repurposing Drugs as Potent Antibiotics.

In order to mitigate antibiotic resistance, a new strategy to increase antibiotic potency and reverse drug resistance is needed. Herein, the translocation mechanism of an antimicrobial guanidinium-functionalized polycarbonate is leveraged in combination with traditional antibiotics to afford a potent treatment for drug-resistant bacteria. Particularly, this polymer-antibiotic combination approach reverses rifampicin resistance phenotype in demonstrating a 2.

Combination of guanidinium and quaternary ammonium polymers with distinctive antimicrobial mechanisms achieving a synergistic antimicrobial effect.

The increasing emergence and spread of antimicrobial resistance are urgent and important global challenges today. The clinical pipeline is lacking in innovative drugs that avoid the development of drug resistance. Macromolecular antimicrobials kill bacteria and fungi through physical disruptions to the cell membrane, which is difficult for microbes to overcome.

Synthesis of Functionalized Cyclic Carbonates through Commodity Polymer Upcycling.

Functionalized cyclic carbonates are attractive monomers for the synthesis of innovative polycarbonates or polyurethanes for various applications. Even though their synthesis has been intensively investigated, doing so in a sustainable and efficient manner remains a challenge. Herein, we propose an organocatalytic procedure based on the depolymerization of a commodity polymer, bisphenol A based polycarbonate (BPA-PC).

Rapid, large-volume, thermally controlled 3D printing using a mobile liquid interface.

We report a stereolithographic three-dimensional printing approach for polymeric components that uses a mobile liquid interface (a fluorinated oil) to reduce the adhesive forces between the interface and the printed object, thereby allowing for a continuous and rapid print process, regardless of polymeric precursor. The bed area is not size-restricted by thermal limitations because the flowing oil enables direct cooling across the entire print area. Continuous vertical print rates exceeding 430 millimeters per hour with a volumetric throughput of 100 liters per hour have been demonstrated, and proof-of-concept structures made from hard plastics, ceramic precursors, and elastomers have been printed.

Subcutaneous vaccination using injectable biodegradable hydrogels for long-term immune response.

Prolonged vaccine release enables gradual immunostimulation, providing long-term immunity. Herein, Vitamin E-PEG-Vitamin E triblock 'ABA' hydrogel, which is formed through physical cross-linking of flower-shaped micelles and can reside in vivo for >17 weeks, was employed for delivery of cancer preventive vaccines to provide sustained anticancer immunity. Mice vaccinated with hydrogel formulations produced a significantly higher quantity of antibodies compared to solution formulations.

Degradable antimicrobial polycarbonates with unexpected activity and selectivity for treating multidrug-resistant Klebsiella pneumoniae lung infection in mice.

Multidrug resistant (MDR) Klebsiella pneumoniae is a major cause of healthcare-associated infections around the world, with attendant high rates of morbidity and mortality. Progressive reduction in potency of antibiotics capable of treating MDR K. pneumoniae infections - including lung infection - as a consequence of escalating drug resistance provides the motivation to develop drug candidates targeting MDR K.

Programmable High-Throughput Platform for the Rapid and Scalable Synthesis of Polyester and Polycarbonate Libraries.

The critical role of composition, architecture, molecular weight, and molecular weight distribution on the functional properties of macromolecular materials underscores the need for reproducible, robust, scalable, and programmable synthetic methods to generate macromolecules that span a systematic and wide range of structure-property space. Herein, we describe the marriage of tunable and highly active organic catalysts with programmed continuous-flow reactors to rapidly generate libraries of polyester and polycarbonate homopolymers and block copolymers with exquisite efficiency and control. Under continuous-flow conditions, highly controlled polymerizations occur with residence times as low as 6 ms (TOF = 24 000 000 h) and can be readily scaled-up to generate polymers at a rate of tens of grams per minute.

Polymers with distinctive anticancer mechanism that kills MDR cancer cells and inhibits tumor metastasis.

Although mortality continues to decline over the past two decades, cancer is still a pervasive healthcare problem worldwide due to the increase in the number of cases, multidrug resistance (MDR) and metastasis. As a consequence of multidrug resistance, cancer treatment must rely on a host of chemotherapeutic agents and chemosensitizers to achieve remission. To overcome these problems, a series of biodegradable triblock copolymers of PEG, guanidinium-functionalized polycarbonate and polylactide (PEG-PGC-PDLA) is designed as chemotherapeutic agents.

Effective encapsulation of apomorphine into biodegradable polymeric nanoparticles through a reversible chemical bond for delivery across the blood-brain barrier.

Apomorphine (AMP, used for treatment of Parkinson's disease) is susceptible to oxidation. Its oxidized products are toxic. To overcome these issues, AMP was conjugated to phenylboronic acid-functionalized polycarbonate through pH-sensitive covalent boronate ester bond between phenylboronic acid and catechol in AMP.