An inexpensive virus detection scheme with high sensitivity and specificity is desirable for broad applications such as the COVID-19 virus. In this article, we introduce the localized surface plasmon resonance (LSPR) principle on the aggregation of antigen-coated gold nanoparticles (GNPs) to detect SARS-CoV-2 Nucleocapsid (N) proteins. Experiments show this technique can produce results observable by the naked eye in 5 mins with a LOD (Limits of Detection) of 150 ng/ml for the N proteins. A comprehensive numerical model of the LSPR effect on the aggregation of GNPs has been developed to identify the key parameters in the reaction processes. The color-changing behaviors can be readily utilized to detect the existence of the virus while the quantitative concentration value is characterized with the assistance of an optical spectrometer. A parameter defined as the ratio of the light absorption intensity at the upper visible band region of 700 nm to the light absorption intensity at the peak optical absorption spectrum of the GNPs at 530 nm is found to have a linear relationship with respect to the N protein concentrations. As such, this scheme could be utilized as an inexpensive testing methodology for applications in POC (Point-of-Care) diagnostics to combat current and future virus-induced pandemics.
A time-
and cost-effective fabrication methodology via a two-mode
mechanical cutting process for multilayer stretchable electronics
has been developed without using the conventional photolithography-based
processes. A commercially available vinyl cutter is used for defining
complex patterns on designated material layers by adjusting the applied
force and the depth of the cutting blade. Two distinct modes of mechanical
cutting can be achieved and employed to establish the basic fabrication
procedures for common features in stretchable electronics, such as
the metal interconnects, contact pads, and openings by the “tunnel
cut” mode, and the flexible overall structure by the “through
cut” mode. Three robust and resilient stretchable systems have
been demonstrated, including a water-resistant, omnidirectionally
stretchable supercapacitor array, a stretchable mesh applicable in
sweat extraction and sensing, and a skin-mountable human breathing
monitoring patch. Results show excellent electronic performances of
these devices made of multilayer functional materials after repetitive
large deformations.
The development of endosomal disruptive
agents is a major challenge
in the field of drug delivery and pharmaceutical chemistry. Current
endosomal disruptive agents are composed of polymers, peptides, and
nanoparticles and have had limited clinical impact. Alternatives to
traditional endosomal disruptive agents are therefore greatly needed.
In this report, we introduce a new class of low molecular weight endosomal
disruptive agents, termed caged surfactants, that selectively disrupt
endosomes via reversible PEGylation under acidic endosomal conditions.
The caged surfactants have the potential to address several of the
limitations hindering the development of current endosomal disruptive
agents, such as high toxicity and low excretion, and are amenable
to traditional medicinal chemistry approaches for optimization. In
this report, we synthesized three generations of caged surfactants
and demonstrated that they can enhance the ability of cationic lipids
to deliver mRNA into primary cells. We also show that caged surfactants
can deliver siRNA into cells when modified with the RNA-binding dye
thiazole orange. We anticipate that the caged surfactants will have
numerous applications in pharmaceutical chemistry and drug delivery
given their versatility.
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