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Non-aqueous organic redox flow batteries (NAORFBs) are considered emerging large-scale energy storage systems due to their larger voltage window as compared to aqueous systems and their metal-free nature. However, low solubility, sustainability, and crossover of redox materials remain major challenges for the development of NAORFBs. Here, we report the use of redox active α-helical polypeptides suitable for NAORFBs. The polypeptides exhibit less crossover than small molecule analogs for both Daramic 175 separator and FAPQ 375 PP membrane, with FAPQ 375 PP preventing crossover most effectivley. Polypeptide NAORFBs assembled with a TEMPO-based polypeptide catholyte and viologen-based polypeptide anolyte exhibit low capacity fade ( ca. 0.1% per cycle over 500 cycles) and high coulombic efficiency (>99.5%). The polypeptide NAORFBs exhibit an output voltage of 1.1 V with a maximum capacity of 0.53 A h L −1 (39% of the theoretical capacity). After 500 charge–discharge cycles, 60% of the initial capacity was retained. Post cycling analysis using spectral and electrochemical methods demonstrate that the polypeptide backbone and the ester side chain linkages are stable during electrochemical cycling. Taken together, these polypeptides offer naturally-derived, deconstructable platforms for addressing the needs of metal-free energy storage. 

Hemorrhage is a prime cause of death in civilian and military traumatic injuries, whereby a significant proportion of death and complications occur prior to paramedic arrival and hospital resuscitation. Hence, it is crucial to develop hemostatic materials that are able to be applied by simple processes and allow control over bleeding by inducing rapid hemostasis, non-invasively, until subjects receive necessary medical care. This tutorial review discusses recent advances in synthesis and fabrication of degradable hemostatic nanomaterials and nanocomposites. Control of assembly and fine-tuning of composition of absorbable ( i.e. , degradable) hemostatic supramolecular structures and nanoconstructs have afforded the development of smart devices and scaffolds capable of efficiently controlling bleeding while degrading over time, thereby reducing surgical operation times and hospitalization duration. The nanoconstructs that are highlighted have demonstrated hemostatic efficiency pre-clinically in animal models, while also sharing characteristics of degradability, bioabsorbability and presence of nano-assemblies within their compositions. 

In this work, we designed and fabricated a nanoscopic sugar-based magnetic hybrid material that is capable of tackling environmental pollution posed by marine oil spills, while minimizing potential secondary problems that may occur from microplastic contamination. These readily-defined magnetic nanocomposites were constructed through co-assembly of magnetic iron oxide nanoparticles (MIONs) and a degradable amphiphilic polymer, poly(ethylene glycol)- b -dopamine-functionalized poly(ethyl propargyl glucose carbonate)- b -poly(ethyl glucose carbonate), PEG- b -PGC[(EPC-MPA)- co -(EPC-DOPA)]- b -PGC(EC), driven by supramolecular co-assembly in water with enhanced interactions provided via complexation between dopamine and MIONs. The composite nanoscopic assemblies possessed a pseudo -micellar structure, with MIONs trapped within the polymer framework. The triblock terpolymer was synthesized by sequential ring-opening polymerizations (ROPs) of two glucose-derived carbonate monomers, initiated by a PEG macroinitiator. Dopamine anchoring groups were subsequently installed by first introducing carboxylic acid groups using a thiol–yne click reaction, followed by amidation with dopamine. The resulting amphiphilic triblock terpolymers and MIONs were co-assembled to afford hybrid nanocomposites using solvent exchange processes from organic solvent to water. In combination with hydrophobic interactions, the linkage between dopamine and iron oxide stabilized the overall nanoscopic structure to allow for the establishment of a uniform globular morphology, whereas attempts at co-assembly with the triblock terpolymer precursor, lacking dopamine side chains, failed to afford well-defined nanostructures. The magnetic hybrid nanoparticles demonstrated high oil sorption capacities, ca. 8 times their initial dry weight, attributed, in part, to large surface areas leading to effective contact between the nanomaterials and hydrocarbon pollutants. Moreover, the naturally-derived polymer framework undergoes hydrolytic degradation to break down into byproducts that include glucose, ethanol and dopamine if not recovered after deployment, alleviating concerns of potential microplastic generation and persistence. 

A polypeptide-based hydrogel system, when prepared from a diblock polymer with a ternary copolypeptide as one block, exhibited thermo-, mechano- and enzyme-responsive properties, which enabled the encapsulation of naproxen (Npx) during the sol–gel transition and its release in the gel state. Statistical terpolymerizations of l -alanine (Ala), glycine (Gly) and l -isoleucine (Ile) NCAs at a 1 : 1 : 1 feed ratio initiated by monomethoxy monoamino-terminated poly(ethylene glycol) afforded a series of methoxy poly(ethylene glycol)- block -poly( l -alanine- co -glycine- co - l -isoleucine) (mPEG- b -P(A-G-I)) block polymers. β-Sheets were the dominant secondary structures within the polypeptide segments, which facilitated a heat-induced sol-to-gel transition, resulting from the supramolecular assembly of β-sheets into nanofibrils. Deconstruction of the three-dimensional networks by mechanical force (sonication) triggered the reverse gel-to-sol transition. Certain enzymes could accelerate the breakdown of the hydrogel, as determined by in vitro gel weight loss profiles. The hydrogels were able to encapsulate and release Npx over 6 days, demonstrating the potential application of these polypeptide hydrogels as an injectable local delivery system for small molecule drugs.