Multiphasic Coacervates Assembled by Hydrogen Bonding and Hydrophobic Interactions.

Coacervation has emerged as a prevalent mechanism to compartmentalize biomolecules in living cells. Synthetic coacervates help in understanding the assembly process and mimic the functions of biological coacervates as simplified artificial systems. Though the molecular mechanism and mesoscopic properties of coacervates formed from charged coacervates have been well investigated, the details of the assembly and stabilization of nonionic coacervates remain largely unknown. Here, we describe a library of coacervate-forming polyesteramides and show that the water-tertiary amide bridging hydrogen bonds and hydrophobic interactions stabilize these nonionic, single-component coacervates. Analogous to intracellular biological coacervates, these coacervates exhibit "liquid-like" features with low viscosity and low interfacial energy, and form coacervates with as few as five repeating units. By controlling the temperature and engineering the molar ratio between hydrophobic interaction sites and bridging hydrogen bonding sites, we demonstrate the tuneability of the viscosity and interfacial tension of polyesteramide-based coacervates. Taking advantage of the differences in the mesoscopic properties of these nonionic coacervates, we engineered multiphasic coacervates with core-shell architectures similar to those of intracellular biological coacervates, such as nucleoli and stress granule-p-body complexes. The multiphasic structures produced from these synthetic nonionic polyesteramide coacervates may serve as a valuable tool for investigating physicochemical principles deployed by living cells to spatiotemporally control cargo partitioning, biochemical reaction rates, and interorganellar signal transport.

Silk Fibroin As an Immobilization Matrix for Sensing Applications.

The development of flexible, biocompatible, and environment-friendly sensors has attracted a significant amount of scientific interest for the past few decades. Among all the natural materials, silk fibroin (SF), due to its tunable biodegradability, biocompatibility, ease of processing, presence of functional groups, and controllable dimensions, has opened up opportunities for immobilizing multitudinous biomolecules and conformability to the skin, among other attractive opportunities. The silk fibroins also offer good physical properties, such as superior toughness and tensile strength. The sensors made of SF as an immobilization matrix have demonstrated excellent analytical performance, sensing even at low concentrations. The significant advantage of silk fibroins is the presence of functional groups along with a controllable conformation transition that enables immobilization of receptor molecules using silk fibroins as an immobilization matrix enables us to entrap the receptor molecules without using any chemical reagents. This review encompasses a detailed discussion on sensors, the advantages of using silk fibroins as an immobilization matrix for various receptors, their applications, and the future research scope in this state-of-the-art technology based upon the explorable applications for silk fibroin-based sensors.

Electrospun nanofiber-based cancer sensors: A review.

Cancer is a malignancy engendering enormous global mortality, steering extensive research for early diagnosis and efficacious prognosis leading to emergence of cancer sensing technologies for multitudinous biomarkers. In this context, nanofibers, imparting high surface area, facile production, morphology control, and synergistic properties attainable, are poised to be inevitable in futuristic sensing devices for predictive diagnostics when integrated with artificial intelligence and machine learning. To this end, fundamentals governing the sensor response and their analytical performance have been discussed. The headways in organic and inorganic nanofibers for biomarker gas sensing, fluid sample sensing and imaging have been supplemented with discussions on materials for nanofiber formation, along with sensitizing materials, and formation of sensing elements by processes like surface deposition on nanofibers, immobilising, calcination, etc. and their effect on final sensing device properties. The review culminates by summarising the conceptual understanding of the hitherto progress leading to achievement of excellent analytical performance giving detection limits to the order of 1.6 pM concentration and response time of as low as 0.5 s. Current bottlenecks in this state of the art have been delineated and pathways for future research are discussed.