A new surface bioconjugation strategy is presented. A polydopamine surface coating provides chemical activation on material surfaces, is resistant to hydrolysis, and offers selectivity in coupling of biomolecules via nucleophilic groups through simple pH control. Control of orientation of immobilized biomolecules may be possible using terminally modified DNA or His‐containing proteins.

A new method for creating layer‐by‐layer (LbL) assembled films on any substrate using polymers inspired by the high catechol content of mussel adhesive proteinsis presented. Catechol‐derivatized polymers permit LbL assembly on challenging substrates without prior surface preparation. Catechol groups incorporated into the LbL film induce the reduction of silver ions to metallic silver when immersedin an aqueous metal salt solution, providing antibacterial properties.

A facile approach for material-independent surface modification using norepinephrine was investigated. pH-induced oxidative polymerization of norepinephrine forms adherent films on vastly different types of material surfaces of noble metals, metal oxides, semiconductors, ceramic, shapememory alloy and synthetic polymers. Secondary biochemical functionalizations such as immobilization of proteins and growth of biodegradable polyester on the poly(norepinephrine) films was demonstrated.Performance of most advanced materials is closely connected to their surface chemical characteristics. Examples include biosensors, medical devices, catalysts, nanomaterials, drug delivery carriers, etc. [1][2][3][4][5] Widespread methods for surface modification, such as self-assembled monolayer (SAM) and organosilane chemistry, work well on particular material surfaces compatible with the specific strategy for surface conjugation, 6 but lack efficacy on broad ranges of material surfaces. Methods that require the use of organic solvents, in some cases under anhydrous conditions, represent further limitations of existing surface modification strategies. Thus, development of versatile aqueous surface modification chemistry remains an important goal.Herein, we report a facile surface modification method utilizing norepinephrine, a small catecholamine molecule. Oxidative polymerization of norepinephrine in alkaline aqueous media modified virtually all material surfaces (noble metals, metal oxides, semiconductors, ceramics, and synthetic polymers), and the modified surfaces serve as useful platforms for biomolecule-conjugation and ring-opening polymerization.Recently, we reported a material-independent surface functionalization strategy involving selfpolymerization of dopamine to form chemically active adherent films on virtually any material surfaces including noble metals, oxides, polymers, semiconductors, and ceramics. 7 The method was inspired by the high content of 3,4-dihydroxy-L-phenylalanine (DOPA) and lysine found Dopamine is considered a small molecule mimic of Mefp-5 in that it contains the catechol and primary amine functional groups found in the side chains of DOPA and Lys residues. Incubation of substrates in an alkaline dopamine solution resulted in oxidative polymerization of dopamine and formation of a heterogeneous polymer coating. 7a A variety of secondary immobilization reactions using the polydopamine coating as a base or 'primer' led to various functional coatings, including grafted polymer coatings, metal films, and self-assembled monolayers.In an effort to further increase the versatility of this strategy, we now report organic thin film formation by derivatives of dopamine, in particular catecholamines that offer chemical functionalities not present in dopamine. Importantly, we find that norepinephrine shares the material-independent coating-forming properties of dopamine, but can also support secondary derivatization of surfaces that is difficult with polydopamine coatings. Unlike polydopamine coatings,...

During the course of their lifespan, erythrocytes actively shed phospholipid-bound, microvesicles (MVs). In stored blood, the number of these erythrocyte-derived MVs have been observed to increase over time, suggesting their potential value as a quality metric for blood products. The lack of sensitive, standardized MV assays, however, poses a significant barrier to implementing MV analyses into clinical settings. Here, we report on a new nanotechnology platform capable of rapid and sensitive MV detection in packed red blood cell (pRBC) units. A filter-assisted microfluidic device was designed to enrich MVs directly from pRBC units, and label them with target-specific magnetic nanoparticles. Subsequent detection using a miniaturized nuclear magnetic resonance system enabled accurate MV quantification as well as the detection of key molecular markers (CD44, CD47, CD55). By applying the developed platform, MVs in stored blood units could also be monitored longitudinally. Our results showed that MV counts increase over time, and thus could serve as an effective metric of blood aging. Furthermore, our studies found that MVs have the capacity to generate oxidative stress and consume nitric oxide. By advancing our understanding of MV biology, we expect that the developed platform will lead to improved blood product quality and transfusion safety.