The design of bright, high quantum yield (QY) materials in the near‐infrared (NIR) spectral region in water remains a significant challenge. A series of cyanine and squaraine dyes varying water solubilizing groups and heterocycles are studied to probe the interactions of these groups with albumin in water. Unprecedented, ′ultra‐bright′ emission in water is observed for a sulfonate indolizine squaraine dye (61.1 % QY) and a sulfonate indolizine cyanine dye (46.7 % QY) at NIR wavelengths of >700 nm and >800 nm, respectively. The dyes presented herein have a lower limit of detection than the most sensitive dyes known in the NIR region for albumin detection by at least an order of magnitude, which enables more sensitive diagnostic testing. Additionally, biotinylated human serum albumin complexed with the dyes reported herein was observed to function as an immunohistochemical reagent enabling high resolution imaging of cellular α‐tubulin at low dye concentrations.
The Front Cover shows a single near‐infrared dye being laser‐excited and dimly fluorescing in an aqueous biological environment compared to a near‐infrared dye bound to albumin fluorescing brightly in the same environment. Cover designed by Karina Kapusta. Read the full text of the Research Article at 10.1002/cptc.202200127.
The challenges faced with current fluorescence imaging agents have motivated us to study two nanostructures based on a hydrophobic dye, 6H-pyrrolo[3,2-b:4,5-b’]bis [1,4]benzothiazine (TRPZ). TRPZ is a heteroacene with a rigid, pi-conjugated structure, multiple reactive sites, and unique spectroscopic properties. Here we coupled TRPZ to a tert-butyl carbamate (BOC) protected 2,2-bis(hydroxymethyl)propanoic acid (bisMPA) dendron via azide-alkyne Huisgen cycloaddition. Deprotection of the protected amine groups on the dendron afforded a cationic terminated amphiphile, TRPZ-bisMPA. TRPZ-bisMPA was nanoprecipitated into water to obtain nanoparticles (NPs) with a hydrodynamic radius that was <150 nm. For comparison, TRPZ-PG was encapsulated in pluronic-F127 (Mw = 12 kD), a polymer surfactant to afford NPs almost twice as large as those formed by TRPZ-bisMPA. Size and stability studies confirm the suitability of the TRPZ-bisMPA NPs for biomedical applications. The photophysical properties of the TRPZ-bisMPA NPs show a quantum yield of 49%, a Stokes shift of 201 nm (0.72 eV) and a lifetime of 6.3 ns in water. Further evidence was provided by cell viability and cellular uptake studies confirming the low cytotoxicity of TRPZ-bisMPA NPs and their potential in bioimaging.
Salmonella infection remains a major global health problem and worsened by lack of appropriate diagnostic tools to aid early detection and teatment, particularly in low-income nations . Salmonella typhi is the most common causative agent of typhoid fever and the prevalence of this illness has been on the increase specifically in areas of poor personal hygiene and sanitation. This study was carried out to further improve the diagnosis of salmonella infection, through a mathematical regression model. An analysis was performed using the logistic regression approach and the predictability of the model was done by extracting fifteen (15) typhoid observations from the obtained samples; for the model to predict their status. The model was able to accurately predict 66.7% of the observations. This study showed an increased prevalence in typhoid fever including a significant correlation between typhoid fever and other parameters. The global burden of this illness can be minimized by proper vaccination, and prompt but appropriate diagnosis and treatment.Further studies and test-meaasures also needs to be carried out to improve diagnosis and treatment regimen.
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