How Surface Plasmon Resonance Works & How We Save You Time & Money

Excedr - Surface Plasmon Resonance Instruments

Ultimately the Excedr lease program can accommodate your lab’s instrument needs and brand/model preferences. Get in touch with us today and see how leasing can save you time and money on your SPRI research platform.

All equipment brands/models are available

The Advantages of Excedr’s SPRI Instrument Leasing Program:

  • Eliminates the upfront cost of purchasing equipment by spreading its cost over time
  • Minimizes equipment downtime with included complete repair coverage and preventive maintenance
  • Takes advantage of potentially 100% tax deductible* payments, providing you significant cash-savings
  • Expedites the administrative work needed for instrument procurement and logistics
  • Conserves working capital,  enabling you to reinvest in your core business and operations (staffing, inventory, marketing/sales, etc.)
  • Accommodates all manufacturer and model preferences

*Please consult your tax advisor to determine the full tax implications of leasing equipment.

a cell, a microplate well, antibodies, and a dot with 6 lines through it

Observing how a chemical substance or biological ligand interacts with a transducer can be referred to as biosensing.

Surface plasmon resonance imaging (SPRI) is a high throughput optical biosensing technique used to study small molecules and provide data on the affinity, specificity, and kinetics of biomolecular interactions.

It is also referred to as surface plasmon resonance microscopy (SPRM) and provides its data by measuring the target molecules’ real-time binding association rates and dissociation rates. It is considered a fundamental principle behind many biosensor applications, diatom photosynthesis, and various lab-on-a-chip sensors.

Surface Plasmon Resonance (SPR) technology is combined with imaging devices to form SPRI and can be used in several different ways.

It is most commonly used to analyze molecular interactions because, unlike many other immunoassays, such as ELISA, SPR assays allow for real-time, label-free detection of biomolecular interactions and provide higher-throughput analysis than many traditional methods.

Surface plasmon resonance is also used for measuring the adsorption onto the surface of metal nanoparticles or onto a planar metal surface (such as gold or silver), as it is the basis behind many other tools that material adsorption onto planar metal. This includes using SPR as a characterization tool for lipid nanoparticles (LNPs) used in drug discovery.

Other SPR applications include observing protein-to-protein, protein-to-antibody, DNA-to-protein, and many other molecular exchanges. Unlike similar analytical techniques, SPR can be used to look at both binding kinetics and binding affinity.

A plasmon refers to the minimum amount, or quantum, of rapid oscillations of electron densities in conducting medium or plasma densities. Surface plasmon relates to this oscillation as it occurs on the surface of a conducting medium such as a metallic surface.

When polarized light hits an electrically conducting surface, such as a metal, some light is absorbed by the object’s surface electrons and resonates with the electrons along the material’s surface. Specifically, it occurs at the interface of the media with different refractive indices. These resonated electrons are the surface plasmons.

Surface plasmon resonance excites electrons on the surface of a conductive layer and detects the resulting oscillations of free electrons. This means that the excited electrons absorb some of the incident light, and the resulting reflected light will now contain an absorption line. This absorption line can then be used to determine various qualities of the material.

SPR Instrumentation, Techniques, & Methods

an outstretched hand face up holding the end of a DNA double helix

Though the critical components of SPR instrumentation are similar across all types, the modes of excitation vary. Three of the most commonly used methods include the Kretschmann-Raether configuration, Otto configuration, and grating coupled.  

In addition to these methods, another important method has been developed as a hybrid method in which electrochemistry and SPR is combined to create a novel SPR technique. It is referred to as electrochemical SPR (ESPR).


The basic instrumentation of SPRI includes an optical measurement system, a fluid handling system, and a sensor chip. Combining these three components is critical and provides the high sensitivity, accuracy, and precision that all scientists require in an assay.

Optical Measurement System

This system comprises a light source and a detector. However, its configuration depends on the design of the instrument itself. Regardless, the light source is used to illuminate the sensor chip, while the detector measures the unique spectrum created by SPR.

Most instruments today rely on a laser to shine laser light through a prism beneath the sensor chip that generates a type of condition that results in a plasmonic wave traveling across the surface of the gold film (part of the sensor chip). The electrical field of this wave extends into the space above the sensor’s surface, where its intensity is measured using the detector.

Fluid Handling System

This fluidics system provides a constant stream of buffer for the coupling process. This stream passes through the flow cell and across the sensor chip, providing a stable flow and environment for the analyte being analyzed. The analyte is inserted into the flowing buffer so that it may interact with the sensor surface. This system is also used for ligand immobilization and analyte regeneration, as well as cleaning.

Sensor Chip

This component is a gold film coated on a glass substrate that has been chemically modified to make it easier to immobilize one of the binding partners onto the biosensor’s surface.

The immobilized molecule is known as the ligand, and the molecule in the solution is known as the analyte. The sensor chip in the device interacts with the fluidic system by using a small flow cell, which allows the analyte to be injected at different concentrations in a very repeatable manner.


Kretschmann-Raether Configuration

This method uses an electrically insulated or dielectric prism, which is why it is considered a prism-based SPR system. A thin, metallic film and the analyte to be observed are put onto the prism. Surface plasmon electromagnetic waves occur when the polarized light is shown through the prism at a specific angle, called the resonant angle.

These waves are also called surface plasmon polariton. Because the metallic layer is placed directly on the prism, this technique allows for more efficient plasmon wave generation.


Otto Configuration

The Otto configuration consists of a dielectric prism, metallic film, and an analyte, similar to the Kretschmann-Raether configuration. However, the difference is that the analyte and the metallic film are not attached to the prism. Instead, there is a thin gap of air or another low index spacer between the prism and the conductive layers.

The light in the prism is internally reflected, and an evanescent wave is created within the air gap. This wave excites the surface plasmon and creates surface plasmon polaritons. This technique is often used to look at SPR in solid-phase mediums.


Grating Couplers

First introduced in 1983, grating couplers use the physical phenomenon of diffraction grating rather than a prism. Diffraction grating is an optical technique that can disperse light of many different wavelengths, such as white light, and diffracts each wavelength at a different angle. This diffraction is accomplished by having the light strike a grating plate with grooves at specific depths and intervals.

In SPR, this grating plate is covered with a conductive metal, like gold or silver. The angle of the light is dependent on the biomolecules on the outside of the grating. By varying the angle of the incident light and capturing the resulting reflected light, a binding curve can be formed and information about the molecules can be determined.



By combining electrochemistry with a powerful optical method like SPR, researchers can monitor and understand biochemical processes much more effectively, simultaneously observing optical and electrochemical properties.

The surface effects that can be studied using ESPR include thin film formation, adsorption/desorption, redox-initiated conformation changes, and polymer formation. And because SPR is sensitive to both the adsorbed layer on the gold electrode and dielectric properties, electrochemically modulated diffusion layers can be detected.


Possible Early Detection of Cancer

Early detection of any severe disease is an essential first step in a patient’s treatment. The earlier the diagnosis, the quicker you can begin to receive treatment. In January of 2019, Monash University announced that they had developed a new method for the early detection of cancer. Associate Professor Qiaoliang Bao and other researchers found a new material that has improved sensitivity in spotting cancerous molecules in DNA and MicroRNA.

Their team used antimonene materials to develop a surface plasmon resonance sensor that identified biomarkers MicroRNA-21 and MicroRNA-155. This relatively low-cost and non-destructive testing could alert people whether or not they have cancer, making proactive treatment feasible.


Surface Plasmon Resonance Instrument Leases to Fit Every Need

a petri dish with a sample inside

Whether you’re interested in surface plasmon resonance or western blot, we can help you finance either system. Give us a call at +1 888-927-3802 or fill out our contact form to learn more about how we can help you achieve your goals.

Operating Lease

This off-balance sheet financing structure provides three options at the end of the term. The lessee has the option to return the equipment to the lessor, renew at a discounted rate, or purchase the instrument for the fair market value. Monthly payments are also 100% tax deductible which yields additional monetary savings.


If you recently bought equipment, Excedr can offer you cash for your device and convert your purchase into a long-term rental. This is called a sale-leaseback. If you’ve paid for equipment within the last ninety days, we can help you recoup your investment and allow you to make low monthly payments. This also frees up money in your budget rather than tying it down to a fixed asset.

Surface Plasmon Resonance Instrument Manufacturers & Models
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GE Healthcare Life Sciences:
Biacore 8K+, Biacore 8K, Biacore S200, Biacore T200, Biacore X100, Biacore X100 Plus Package, Biacore C

OpenPlex, XelPlex, SPRi-CFM, SPRi-Arrayer

Biosensing Instruments:
SPRm 200 Series, BI-4500 Series, BI-2500 Series

ProteOn System, ProteOn XPR36

Reichert Technologies:

Pioneer FE System, Pioneer FE SPR System

Sierra SPR-32

BiOptix Analytical:


CORgI I, CORgI II, CORgI SD, CORgI ID, SpectraCube LSPR System

MP-SPR Navi, 420A ILVES, 220A NAALI, 210A VASA, 200 OTSO

Nano SPR:
NanoSPR6, NanoSPR8, NanoSPR9, NanoSPR103

PlexArray HT System

Nicoya Lifesciences:

Affinite Instruments:

IBIS Technologies:
IBIS-MX96, SensEye Sensor

and more!


Operating Capital Benefits

Operating Capital Benefits

Excedr's operating lease structure allows you to keep your business credit line open for expansions, staffing, and other operational expenses. Additionally, it strengthens the cash flow of your business and keeps cash reserves free for business development opportunities.

Effects on Credit

Effects on Credit

Leasing / renting provides you with non-dilutive financing and does not hinder your future borrowing ability. You're able to acquire the equipment you need without the baggage associated with traditional financing.

Speed of Approval

Speed of Approval

Excedr's program allows you to respond quickly as your need for equipment and technology arises. You can be approved with minimal documentation and have the equipment you need in operation and generating revenue for your business quickly.

Refurbished Equipment

Refurbished Equipment

Unlike traditional financing and leasing companies, the Excedr program can accommodate refurbished equipment in addition to demo units. If you are looking for additional cost-savings, we recommend considering this option.