Corona phase molecular recognition (CoPhMoRe) uses a heteropolymer adsorbed onto and templated by a nanoparticle surface to recognize a specific target analyte. This method has not yet been extended to macromolecular analytes, including proteins. Herein we develop a variant of a CoPhMoRe screening procedure of single-walled carbon nanotubes (SWCNT) and use it against a panel of human blood proteins, revealing a specific corona phase that recognizes fibrinogen with high selectivity. In response to fibrinogen binding, SWCNT fluorescence decreases by >80% at saturation. Sequential binding of the three fibrinogen nodules is suggested by selective fluorescence quenching by isolated sub-domains and validated by the quenching kinetics. The fibrinogen recognition also occurs in serum environment, at the clinically relevant fibrinogen concentrations in the human blood. These results open new avenues for synthetic, non-biological antibody analogues that recognize biological macromolecules, and hold great promise for medical and clinical applications.

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Corona phase molecular recognition (CoPhMoRe) is a technique whereby an external, adsorbed phase around a colloidal nanoparticle is selected such that its molecular conformation or interaction recognizes a specific target analyte. In this work, we employ a high-throughput screening of a library of poly(ethylene glycol) (PEG)-conjugated lipids adsorbed onto near-infrared fluorescent single-walled carbon nanotubes to discover a corona phase selective for insulin. We find that a C-PEG(2000 Da)-ceramide causes a 62% fluorescent intensity decrease of the (10,2) chirality nanotube in the presence of 20 μg/mL insulin. The insulin protein has no prior affinity toward the C-PEG(2000 Da)-ceramide molecules in free solution, verified by isothermal titration calorimetry, and the interaction occurs only upon their adsorption onto the single-walled carbon nanotube scaffolds. Testing a panel of proteins originating from human blood as well as short 7 amino acid fragments of the insulin peptide rules out nonselective recognition mechanisms such as molecular weight, isoelectric point, and hydrophobicity-based detection. Interestingly, longer fragments of isolated α- and β-peptide chains of insulin are detected by the construct, albeit with lower affinity compared to that of the intact insulin protein, suggesting that the construct recognizes insulin in its native form and conformation. Finally, the insulin recognition and the quantification of its solution concentration were demonstrated both in buffer and in blood serum, showing that the CoPhMoRe construct works in this complex environment despite the presence of potential nonspecific adsorption. Our results further motivate the search for nonbiological synthetic recognition sites and open up a new path for continuous insulin monitoring in vivo with the hope of improving glycemic control in closed-loop artificial pancreas systems.

a b s t r a c tCorona phase molecular recognition (CoPhMoRe) is a phenomenon whereby a polymer or surfactant corona phase wrapped around a nanoparticle selectively recognizes a particular molecule. The method can potentially generate non-biological, synthetic molecular recognition sites, analogous to antibodies, for a broad range of biomedical applications, including new types of sensors, laboratory and clinical assays, as well as inhibitors and targeted therapeutics. In this work, we utilize near infrared fluorescent single-walled carbon nanotubes (SWNTs) wrapped with specific single stranded DNA sequences to explore the (n,m) chirality dependence of CoPhMoRe. Specific DNA oligonucleotide sequences are known to recognize and interact uniquely with certain (n,m) SWNTs enabling their enrichment in ion exchange chromatography. We explore the CoPhMoRe effect using corona phases constructed from a library of 24 such sequences, screening against a biomolecule panel that includes common neurotransmitters, amino acids, saccharides and riboflavin. Example sequences include (ATT) 4 , (TAT) 4 and (ATTT) 3 which recognize (7,5), (6,5) and (8,4) SWNTs, respectively. We find that these recognition sequences indeed form CoPhMoRe phases that are distinct among SWNT chiralities, and appear to pack more densely as to exclude analyte adsorption on the chirality they recognize. These results have encouraging implications for the controlled design of CoPhMoRe phases for biomedical applications.

Background mRNA vaccines hold great potential as therapeutic techniques against viral infections due to their efficacy, safety, and large-scale production. mRNA vaccines offer flexibility in development as any protein can be produced from mRNA without altering the production or application process. Objective This review highlights the iterative optimization of mRNA vaccine structural elements that impact the type, specificity, and intensity of immune responses leading to higher translational potency and intracellular stability. Results Modifying the mRNA structural elements particularly the 5′ cap, 5′-and 3′-untranslated regions (UTRs), the coding region, and polyadenylation tail help reduce the excessive mRNA immunogenicity and consistently improve its intracellular stability and translational efficiency. Conclusion Further studies regarding mRNA-structural elements and their optimization are needed to create new opportunities for engineering mRNA vaccines.