Combining Bioorthogonal Chemistry with Fluorescent Silica Nanoparticles for the Ultrasensitive Detection of the HIV-1 p24 Antigen.

Early detection and viral concentration monitoring of human immunodeficiency virus in resource-poor settings are important to control disease spread and reduce mortality. Nucleic acid amplification tests are expensive for low-resource settings. Lateral flow antibody tests are not sensitive if testing is performed within 7-10 days, and these tests are not quantitative.

Palladium encapsulated mesoporous silica nanoparticles for the rapid detection of analytes.

We designed a simple, inexpensive, and user-friendly assay using mesoporous silica nanoparticles to detect analytes. Highly stable and uniform palladium nanoparticles covered with mesoporous silica (Pd@mSiO) were generated and characterized extensively using physical methods. Human Serum Albumin (HSA) protein or ssDNA specific to the HIV gag region was capped onto the Pd@mSiO electrostatically.

Inflammatory bowel disease biomarkers.

Inflammatory bowel disease (IBD) is characterized as chronic inflammation in the gastrointestinal tract, which includes two main subtypes, Crohn's disease and ulcerative colitis. Endoscopy combined with biopsy is the most effective way to establish IBD diagnosis and disease management. Imaging techniques have also been developed to monitor IBD.

Toward Point-of-Care Diagnostics to Monitor MMP-9 and TNF-α Levels in Inflammatory Bowel Disease.

We have investigated the association of matrix metallopeptidase 9 (MMP-9) and tumor necrosis factor α (TNF-α) levels with colitis severity using an established IL10-/- mouse model, which reflects the severity of inflammation in humans with inflammatory bowel disease (IBD). We found that MMP-9 and TNF-α correlated with colitis severity. In parallel, we developed assays to detect fecal MMP-9 and serum TNF-α using "cap and release" mesoporous silica nanoparticles (MSNs).

ASSURED-SQVM diagnostics for COVID-19: addressing the why, when, where, who, what and how of testing.

: SARS-CoV-2, the new coronavirus that originated in 2019, continues to impact every aspect of society in a profound manner. Testing will remain an important tool to mitigate the effects of this pandemic as early and accurate diagnosis can lead to appropriate countermeasures to reduce mortality and morbidity. However, testing isn't a simple yes/no answer as the target and host are complex, the virus is a moving target, there is a plethora of tests that identify different parts of the virus and have their own limits and range of detection, and when prevalence is low, false positives and negatives can be very high.

Point-of-Care Monitoring of Colitis Using Intestinal Alkaline Phosphatase in Inflammatory Bowel Disease.

Intestinal Alkaline Phosphatase (IAP) was investigated as a potential biomarker to monitor colitis in a mouse model of Inflammatory Bowel Disease (IBD). We developed a Point-Of-Care (POC) assay to detect IAP with a glucose meter in 15 min. We synthesized a paracetamol-bearing compound specifically cleaved by IAP to release paracetamol, which can be detected with a personal glucometer.

Rapid, user-friendly, and inexpensive detection of azidothymidine.

Strict adherence to highly active antiretroviral therapy (HAART) is very important to improve the quality of life for HIV-positive patients to reduce new infections and determine treatment success. Azidothymidine (AZT) is an antiretroviral drug commonly used in HAART treatment. In this research, an "add, mix, and measure" assay was developed to detect AZT within minutes.

Fluorescent sialic derivatives for the specific detection of influenza viruses.

Early and accurate diagnosis of influenza viruses can decrease its harmful impact. Here, we have synthesized fluorescent sialic acid derivatives that are cleaved by influenza neuraminidases (NAs) and not by Streptococcus pneumoniae that also inhabits the human olfactory. We have also attempted to develop assays that could differentiate between influenza virus and S.

Detection of Enzymes, Viruses, and Bacteria Using Glucose Meters.

We have developed innovative assays that can detect enzymes rapidly. Paracetamol- or catechol-bearing compounds, when exposed to their respective enzymes, released paracetamol or catechol, which can be detected using a standard glucose meter. This approach was used to detect a number of diverse analytes that include enzymes such as β-galactosidase and α-mannosidase and pathogens such as influenza viruses, Streptococcus pneumoniae, and E.

Multivalent oleanolic acid human serum albumin conjugate as nonglycosylated neomucin for influenza virus capture and entry inhibition.

We report the synthesis of multivalent oleanolic acid (OA) protein conjugates as nonglycosylated neomucin mimic for the capture and entry inhibition of influenza viruses. Oleanolic acid derivatives bearing an amine-terminated linker were synthesized by esterification of carboxylic acid and further grafted onto the human serum albumin (HSA) via diethyl squarate method. The binding of hemagglutinin (HA) on the virion surface to the synthetic neomucin was evaluated by hemagglutination inhibition assay.

Highly specific and rapid glycan based amperometric detection of influenza viruses.

Rapid and precise detection of influenza viruses in a point of care setting is critical for applying appropriate countermeasures. Current methods such as nucleic acid or antibody based techniques are expensive or suffer from low sensitivity, respectively. We have developed an assay that uses glucose test strips and a handheld potentiostat to detect the influenza virus with high specificity.

Toward the Development of the Next Generation of a Rapid Diagnostic Test: Synthesis of Glycophosphatidylinositol (GPI) Analogues of Plasmodium falciparum and Immunological Characterization.

A large number of proteins in malaria parasites are anchored using glycophosphatidylinositols (GPIs) with lipid tails. These GPIs are structurally distinct from human GPIs. Plasmodium falciparum GPIs have been considered as potential vaccine candidates because these molecules are involved in inducing inflammatory responses in human hosts, and natural anti-GPI antibody responses have been shown to be associated with protection against severe disease.

Multivalent S-sialoside protein conjugates block influenza hemagglutinin and neuraminidase.

A new class of S-sialoside Human Serum Albumin (HSA) and Bovine Serum Albumin (BSA) conjugates were prepared to enhance the binding affinity to hemagglutinin (HA) and neuraminidase (NA). The valency of glycoconjugates was controlled by the reaction ratio of the S-sialoside monomer and protein. Hemagglutination inhibition assay showed that these synthetic glycoproteins have higher affinity to HA than the small clusters of sialosides with lower valency, due to multivalent effect and optimized three dimensional presentation of sialosides on the protein platform.

Synthesis and Evaluation of Biotinylated Bivalent HistoBlood Group Antigens for Capturing Human Noroviruses.

A panel of biotinylated bivalent H-type glycans that have been reported as binding ligands for human noroviruses were synthesized using a modular synthetic strategy. These glycoconjugates were attached to streptavidin-coated magnetic beads and used to recover human norovirus from fecal samples using a magnetic bead-based assay. The biotinylated bivalent glycans synthesized for this study exhibited similar or better capturing ability when compared to commercial biotinylated glycopolymers.

Polyvalent effect enhances diglycosidic antiplasmodial activity.

An efficient and facile total synthesis of diglycoside Matayoside D isolated from the root bark of Matayba guianensis with antiplasmodial activity have been accomplished in 11 steps with 5% overall yields starting from commercially available glucose and rhamnose. Furthermore, a class of the diglycosidic derivatives with different lengths of the linker and valences were also prepared and evaluated for their antiplasmodial activities against chloroquine-susceptible (3D7) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Low valent and short linker attached diglycoside show no enhancement of the antiplasmodial activity while polyvalent conjugates showed enhanced antiplasmodial activity with IC50 value at least 20 fold better than that of the corresponding diglycosidic monomer.

Neuraminidase Resistant Sialosides for the Detection of Influenza Viruses.

We report the synthesis of influenza virus neuraminidase (NA) resistant sialosides that include different glycoside linkages (C-, S-, and triazole). These unnatural sialosides were printed onto glass slides to generate a small focused microarray. We evaluated the binding affinity of multiple lectins and compared the stability of these sialosides with O-linked sialosides toward influenza virus neuraminidase and intact virus.

Indirect Detection of Glycosidases Using Amperometry.

Glycosidases are essential enzymes that cleave glycoside bonds. The presence of glycosidases have been widely used to detect pathogens, label cells/tissues, and report specific diseases. We have developed a rapid electrochemical assay to detect glycosidases.

Electrochemical assay to detect influenza viruses and measure drug susceptibility.

An electrochemical assay has been designed to rapidly diagnose influenza viruses. Exposure of a glucose-bearing substrate to influenza viruses or its enzyme, neuraminidase (NA), releases glucose, which was detected amperometrically. Two methods were used to detect released glucose.

Glycan based detection and drug susceptibility of influenza virus.

We have developed a panel of synthetic glycans as receptor mimics for the specific capture of influenza viruses. The glycans were printed onto commercial glass slides using a free amine at the end of a spacer to generate a small focused microarray. The microarray was evaluated for its ability to capture three different strains of influenza A virus, two H1N1, A/Brisbane/59/2007 and A/Solomon Islands/3/2006 and one H3N2, A/Aichi/2/1968.

Bifunctional thiosialosides inhibit influenza virus.

We have synthesized a panel of bivalent S-sialoside analogues, with modifications at the 4 position, as inhibitors of influenza virus. These first generation compounds show IC50 values ranging from low micromolar to high nanomolar in enzyme inhibition and plaque reduction assays with two intact viruses, Influenza H1N1 (A/California/07/2009) and H3N2 (A/Hongkong/8/68).

Binding of Pk-trisaccharide analogs of globotriaosylceramide to Shiga toxin variants.

The two major forms of Shiga toxin, Stx1 and Stx2, use the glycolipid globotriaosylceramide (Gb3) as their cellular receptor. Stx1 primarily recognizes the Pk-trisaccharide portion and has three Pk binding sites per B monomer. The Stx2a subtype requires glycolipid residues in addition to Pk.

Capture of uropathogenic E. coli by using synthetic glycan ligands specific for the pap-pilus.

Biotinylated mono- and biantennary di-/trisaccharides were synthesized to evaluate their ability to capture E. coli strains that express pilus types with different receptor specificities. The synthesized biotinylated di-/trisaccharides contain Galα(1→4)Gal, Galα(1→4)GalNHAc, GalNHAcα(1→4)Gal, Galα(1→4)Galβ(1→4)Glc and GalNHAcα(1→4)Galβ(1→4)Glc as carbohydrate epitopes.

Detection of carbohydrate binding proteins using magnetic relaxation switches.

We have developed a simple, rapid, and sensitive carbohydrate-based magnetic relaxation switch assay for the detection of carbohydrate binding proteins. This technique was used to detect lectins and toxins that are known to bind to specific carbohydrates. Lectins that bind to the same carbohydrate displayed differential aggregation profiles because of differences in the structure and number of binding sites of the lectins.

Glycan encapsulated gold nanoparticles selectively inhibit shiga toxins 1 and 2.

Shiga toxins (Stx) released by Escherichia coli O157:H7 and Shigella dysentriae cause life-threatening conditions that include hemolytic uremic syndrome (HUS), kidney failure, and neurological complications. Cellular entry is mediated by the B-subunit of the AB(5) toxin, which recognizes cell surface glycolipids present in lipid raft-like structures. We developed gold glyconanoparticles that present a multivalent display similar to the cell surface glycolipids to compete for these toxins.

Identification and characterization of the carbohydrate ligands recognized by pertussis toxin via a glycan microarray and surface plasmon resonance.

Binding of pertussis toxin (PTx) was examined by a glycan microarray; 53 positive hits fell into four general groups. One group represents sialylated biantennary compounds with an N-glycan core terminating in alpha2-6-linked sialic acid. The second group consists of multiantennary compounds with a canonical N-glycan core, but lacking terminal sialic acids, which represents a departure from the previous understanding of PTx binding to N-glycans.