Spontaneous Sequestration of Proteins into Liquid Crystalline Microdroplets

Abstract

In this work a facile method for fabricating protein‐sequestered liquid crystal (LC) emulsion droplets based on the uptake of surface‐engineered protein–polymer surfactant (PS) core–shell bioconjugates is described. Uptake of myoglobin‐PS, bovine serum albumin‐PS, Zn‐porphyrin myoglobin‐PS, horseradish peroxidase‐PS, and glucose oxidase‐PS occurs without structural or functional degradation, and gives rise to sequestration within the interior or at the surface of 4‐cyano‐4′‐pentylbiphenyl (5CB) nematic droplets depending on the surface modification of the protein‐PS bioconjugates. Differences in uptake behavior are used to achieve the spontaneous positional assembly of multiple proteins in the LC phase, and the use of spatially separated glucose oxidase‐PS and horseradish peroxidase‐PS bioconjugates is demonstrated to produce 5CB based droplets capable of housing an enzyme cascade reaction. This method opens a pathway for the development of bioactive liquid crystal droplets and can have potential applications in the optical sensing of biomolecular substrates.

Fuel‐Driven and Enzyme‐Regulated Redox‐Responsive Supramolecular Hydrogels

“…The re‐oxidation behavior was tested for 4 more cycles by adding a fixed 5 m m concentration of d ‐glucose at the end of each cycle (Figure 1 c , inset). We note that cascade reactions of GOx and HRP have been used for the modification of soft matter such as fabrication of bio‐functional liquid crystal droplets, [24] nanoreactor coacervates, [25] mechanoresponsive sponges, [26] and biocatalytic electrodes. [27] The mechanism of the cascade reaction involves oxidation of d ‐glucose by GOx largely aided by its cofactor FAD to form β‐ d ‐gluconate ions and FADH 2 .…”

“…ABTS in the presence of H 2 O 2 is known to change into the chromophore ABTS .+ radical cation, which absorbs at 420 nm while formation of Fc + was analyzed at 630 nm as before using UV/Vis spectroscopy. [ 24 , 26 ] While in the presence of O 2 , ABTS and Fc converted rapidly into ABTS .+ and Fc + , respectively, on reaction with H 2 O 2 , there was no transformation seen in either case in the of absence of O 2 (SI Figure S2, methods (v)(ii)). From the above experiments, it appears that GOx[FADH 2 ] reduces Fc + ions first, providing Fc instantly, and then reacts with O 2 to form H 2 O 2 , which in the presence of HRP reformed the oxidation fuel initiating in situ re‐oxidation of Fc (Scheme 1 ).…”

From vesicles to materials: bioinspired strategies for fabricating hierarchically structured soft matter

“…Drops of controlled sizes can be produced with microfluidics, as exemplified in figure 3 a . If drops are stabilized with appropriate amphiphilic molecules such as protein-polymer block-copolymers, they can selectively capture active ingredients like functional proteins, thereby opening up possibilities to design minimal smart compartments [73]. Most of the reagent-loaded block-copolymer stabilized drops are prone to coalescence if stored at high densities [74] such that they are typically used as individually dispersed, spatially separated entities.…”

Brennstoffbetriebene und enzymregulierte redoxresponsive supramolekulare Hydrogele

“…Das Rückoxidationsverhalten wurde durch die Zugabe von 5 m m d ‐Glucose am Ende jedes Zyklus über vier weitere Zyklen beobachtet (Abbildung 1 c, Einschub). Wir weisen darauf hin, dass Kaskadenreaktionen von Gox und HRP für die Modifikation von weicher Materie, zum Beispiel biofunktionellen Flüssigkristalltropfen, [24] Nanoreaktor‐Koazervaten, [25] mechanoresponsiven Schwämmen [26] oder biokatalytischen Elektroden, [27] benutzt wurden. Der Mechanismus der Kaskadenreaktion involviert die Oxidation von d ‐Glucose durch GOx und dessen Cofaktor FAD.…”

“…Nützlich ist hier, dass ABTS durch H 2 O 2 zum Radikalkation ABTS .+ oxidiert wird, das eine charakteristische Absorption bei 420 nm aufweist. Dies konnte wie zuvor bei Fc + (630 nm) durch UV/Vis‐Spektroskopie charakterisiert werden [24, 26] . In Anwesenheit von O 2 wurden sowohl ABTS als auch Fc durch H 2 O 2 schnell in ABTS .+ bzw.…”