Application Category: Traditional SPR

Microbial extracellular polymeric substances (EPS) with redox functional groups play a vital role in the bioconversion of pollutants, which can affect their reactivity toward diverse environmental pollutants. However, the redox …

Entry level surface plasmon resonance (SPR) tools with dual channels have only one measurement point since the other channel is always used as a reference.1 Therefore, increasing efforts have been …

Lysozyme (LZM) is found in body secretions like saliva, and it can catalytically hydrolyze peptidoglycans and exert catalysis-independent antimicrobial properties.1 Additionally, it is a valuable component in pharmaceutical and food …

IgG deficiencies could be a major reason for impaired humoral immunity, whereas very high IgG levels could be a result of chronic infections, autoimmune disorders, and allergies.1 The levels of …

Kinetics of an antibody-antigen interaction forms the basis for immunological response and antibody therapeutics,
which is one of the fastest areas of growth in the pharma industry. Affinity and avidity of antibodies are the characteristics which define the overall efficacy of binding kinetics.

Integrins are heterodimeric receptors which help in cell adhesion and are ubiquitous to all metazoans.1 They also play a vital role in numerous cellular processes including cell growth, proliferation, differentiation, …

This application note shows the application of the single-injection measurement technique in binding kinetic studies between COVID-19 S1 and ACE2 proteins. The five-channel SPR instrument, with the BI-DirectFlow™ technology, provides a unique multi-channel technique for precise sample delivery and high-quality measurement.

The coronavirus 2019 (COVID-19) pandemic continues to evolve. This disease is caused by the highly contagious coronavirus 2 (SARS-CoV-2) and is initiated by the viral invasion into host cells through viral attachment to angiotensin (Ang)-converting enzyme 2 (ACE2). ACE2, expressed in numerous different tissues, is the receptor through which the COVID-19 spike-protein (S-protein) gains entry into cells for subsequent viral replication.

Alzheimer’s disease (AD) is currently ranked as the sixth leading cause of death in the United States and is the most common neurological disorder. Production and accumulation of amyloid-beta (Aβ) peptides in the brain are a hallmark of AD. Among Aβ peptides of different lengths, Αβ(1-42) has the highest propensity to aggregate.

This work demonstrates the excellent potential of highly sensitive carboxyl-graphene oxide (carboxyl-GO) based surface plasmon resonance (SPR) immunosensor for the detection of lung cancer for cytokeratin 19 biomarker in human …

Glycogen is the primary storage form of glucose. Glycogen synthesis and breakdown are tightly controlled by glycogen synthase (GYS) and phosphorylase, respectively. The enzyme responsible for the process is protein …

Streptavidin (SA) sensor chips are commonly used for kinetic interactions of biotinylated ligands. Streptavidin is a tetrameric molecule with an extremely high affinity towards biotin and， because of its binding …

Protein-protein interactions are essential for many biochemical transformations and cellular processes. However, traditional methods of detecting these Surface plasmon resonance (SPR) is capable of analyzing protein-protein interactions kinetically while consuming little protein sample and does not rely on absorbance/fluorescence properties of proteins. This application note describes the SPR analysis of label-free protein-protein interactions found in the mycofactocin biosynthetic pathway.

By combining SPR with electrochemical methods, many new capabilities and applications are now possible. This application note describes the measurement of apoptosis of cancer cells (HepG2) after treatment of Daunorubicin (DNR), an anti-cancer drug commonly used to treat specific types of leukemia.

A major advantage of SPR technology is that the detection does not require the analyte to be labeled, such as with a fluorescent molecule or a redox-active tag. This is because SPR directly detects changes in refractive index resulting from changes in mass at the sensor chip surface. For researchers interested in pharmacology and pharmacokinetics or in general pharmaceutical research or drug discovery, this capability of label-free detection is particularly attractive.

In 2008, the illegal adulteration of infant milk products with melamine (structure shown in FIG 1) led to an outbreak of adverse kidney and urinary effects in thousands of children in China.[1] Clandestine addition of melamine in milk products was to boost the detectable protein contents. Because of the severe impact of melamine on human health, the World Health Organization (WHO)

Vascular endothelial growth factor (VEGF) is an angiogenic signal protein biomarker produced by oxygen-hungry cells to stimulate the growth of blood vessels.[1] It binds to specialized receptors on the surfaces of endothelial cells and directs them to grow new blood vessels during embryonic development. Certain types of tumor cells produce abnormally large amounts of VEGF or block the action of angiogenesis inhibitors

Some biomolecules such as enzymes can exhibit much greater biological activities at physiological temperature (37.5 °C) or higher (e.g., DNA polymerase). The focus of this study is to screen for potential inhibitors of β-site amyloid precursor protein cleaving enzyme 1 (BACE1). BACE1 is an enzyme that cleaves the transmembrane amyloid precursor protein to produce the amyloid beta

Alzheimer’s disease (AD) is the most common neurodegenerative disorder, affecting over 6.5 million people over the age of 65 in the U. S. In the senile plaques of AD patient’s brain, the major components are peptides composed of 39–43 amino acid residues (referred to as the amyloid β or Aβ peptides).[1-2] One of the hypotheses for AD neuropathology is that the misfolding and subsequent aggregation of these peptides

The complement system is an essential component of the human innate immune system, playing a critical role as a defense mechanism against invading pathogens, priming adaptive immune responses and helping to remove immune complexes and apoptotic cells. Three different pathways comprise the complement system: the classical, lectin and alternative pathways [1]. While the complement system plays a central role

SPR is sensitive to various processes taking place on or near a sensor chip. The SPR sensor chip can also simultaneously serve as a working electrode for electrochemical measurements. Combining electrochemical with SPR measurements has led to the development of Electrochemical SPR (EC-SPR). To date, EC-SPR has been used in the analysis of trace metal ions, detection of surface bound redox species, electrochemical polymerization

This application note describes the simultaneous SPR detection of wild-type and mutant p53 proteins in cancer cell laysates. p53 is a transcription factor (i.e., DNA-binding protein) that plays an important role in DNA repair and tumor suppression by inhibiting the growth of tumor cells through eliciting either cell-cycle arrest or apoptosis [1-3]. In solution, p53 molecules tetramerize at their C-termini and the resultant p53 tetramer can bind

Surface charge density is a basic quantity that is directly relevant to many phenomena, from surface interactions to DNA hybridization. Measurement and quantification of surface charge density can lead to a better understanding of biomolecular interactions on surfaces. To date, different techniques have been developed to measure surface charge density, including potentiometric titration, atomic force microscopy and reflection interference

Surface Plasmon Resonance (SPR) can be applied as a convenient, sensitive and label-free technique to study various surface phenomena. One such example is the Vroman effect exhibited by protein adsorption onto surfaces. This important effect arises from the fact that protein adsorption capability onto a surface depends on motility, which is intimately related to its molecular weight. In general, a high molecular weight (HMW) protein adsorbs

Endotoxin (commonly referred to as lipopolysaccharide in bacteriology) is associated with the outer membrane of Gram-negative bacterial pathogens such as Escherichia coli, Salmonella, Shigella, and Pseudomonas [1-2]. The interaction between endotoxin and bacterial cell surface is schematically depicted in Figure 1. Endotoxin elicits a series of pleiotropic effects on cells or organisms and is therefore harmful to most mammals

In recent years, SPR has been used as an alternative detector for monitoring elution of a variety of species (e.g., polysaccharides and proteins [1-4]) out of liquid chromatographic (LC) columns. In addition to simplicity and fast speed the SPR detector can detect any eluent, as long as its index of refraction is different from that of the carrier buffer. The open design of the BI-SPR instruments allows users to conveniently connect

In restriction digestion, BSA has been used to stabilize enzymes during DNA digestion. It is also widely used as a biomolecule to block active sites on surfaces. Formation of the anti-BSA/BSA immune complex is relevant to studies of the receptor site of the red blood cells..

SPR (SPR) has been demonstrated as a powerful technique for rapid, sensitive, and label-free genetic analysis [1-5]. When the sensor surface is coated with a single sensing (probe) DNA, SPR can be used for both affinity binding studies (i.e., kinetic measurements) and concentration detection of a target DNA. However, the concentration detection levels for SPR and SPR imaging are typically at low nanomolar (nM) [3, 4],

SPR has been demonstrated to be a powerful optical technique for bioaffinity studies at the solid/solution interface. In general, SPR measures the change in refractive index originated from the binding of a solution species with a molecule pre-immobilized onto the SPR sensor chip. The advantages of SPR include its simplicity, high sensitivity, obviation of sample labeling, and amenability for real-time analysis

Flow-injection SPR has been demonstrated as a viable alternative for sensitive detection of heavy metal ions at trace levels [1-4]. The impetus behind using SPR for elemental analysis stems from its high sensitivity, simplicity, compact design (for possible field-based work), and universal detection mechanism (e.g., any elemental species adsorbed onto the SPR sensor can cause a detectable signal). The challenge, however, is to prepare a chemically or

In addition to studies of redox-induced conformational changes of surface-bound proteins (cf. Application Note #102), electrochemical SPR can be used to quantify the amount of metal electrodeposited onto a surface and reorganization of organic thin films upon redox reactions. A BI-SPR 1000 was used to quantify the amount of Cu deposited and stripped during Cu2+ reduction/Cu oxidation in a CuSO4 solution

Both electrochemical and surface plasmon resonance (SPR) techniques measure various processes taking place at or near an electrode surface. Combining the two techniques allows one to obtain new insight into these interfacial processes. One example is redox-induced conformational changes in surface-bound protein molecules. However, most SPR setups are not suitable for monitoring fast kinetics or small thickness variations

Understanding conformational changes in proteins and other biomolecules is important because of their critical roles in many biological functions and processes. These conformational changes are often small and fast, making it difficult to measure and monitor. Surface Plasmon Resonance (SPR) is capable to detect rather small conformational changes in surface bound molecules [1]. However, most SPR setups are not suitable