Name: spr biosensors for tracking binding kinetics
Uploaded: 2023-04-30T06:31:51.000Z
Duration: 6 min 58 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Physical Science

waves-and-their-applications-in-technologies-for-information-transfer

Waves and Their Applications in Technologies for Information Transfer

HS-PS4-5

Surface Plasmon Resonance (SPR)

A ressonância de plasmon superficial (SPR) é o fenômeno óptico subjacente por trás de biosensores livres de rótulos para avaliar a afinidade molecular, cinética, especificidade e concentração de biomoléculas. Em SPR, interações biomoleculares ocorrem em um biosensor feito de uma fina camada de metal em um prisma. As interações em tempo real das biomoléculas podem ser monitoradas medindo as mudanças de luz refletidas na parte inferior do metal.
Este vídeo descreve os conceitos básicos da RSE e como ele é usado para analisar e visualizar interações biomoleculares. Isso é seguido por uma preparação amostral e um protocolo experimental para investigar taxas vinculantes usando SPR. Na seção de aplicações, imagens SPR, SPR localizada e SPR aprimorada de ponto quântico são explorados.

ressonância de plasmons de superfície (spr)

A ressonância de plasmon superficial (SPR) é o fenômeno óptico subjacente por trás de biosensores livres de rótulos para avaliar a afinidade molecular, cinética, especificidade e concentração de biomoléculas. Em SPR, interações biomoleculares ocorrem em um biosensor feito de uma fina camada de metal em um prisma. As interações em tempo real das biomoléculas podem ser monitoradas medindo as mudanças de luz refletidas na parte inferior do metal.
Este vídeo descreve os conceitos básicos da RSE e como ele é usado para analisar e visualizar interações biomoleculares. Isso é seguido por uma preparação amostral e um protocolo experimental para investigar taxas vinculantes usando SPR. Na seção de aplicações, imagens SPR, SPR localizada e SPR aprimorada de ponto quântico são explorados.
<div class="chapter_text" id="script_0">
A ressonância de plasmon superficial, ou SPR, é o fenômeno subjacente por trás de certos biosensores livres de rótulos para avaliar interações de vinculação e adsorção de biomoléculas. Ensaios de vinculação que requerem rotulagem, como o ELISA, podem ser um processo demorado, podendo alterar a funcionalidade do analito. Em SPR, interações biomoleculares ocorrem em um sensor especial feito de uma fina camada de metal em uma face de um prisma. Ao monitorar as mudanças de luz refletidas na parte inferior do metal, os instrumentos SPR visualizam essas interações em tempo real sem o uso de etiquetas. Este vídeo introduzirá os princípios da SPR, um procedimento geral para imagem SPR, e algumas aplicações de na bioquímica.
</div>
<div class="chapter_text" id="script_1">
Um sensor SPR é geralmente feito de uma fina camada de um metal nobre em cima da face de um prisma. Para tirar leituras do sensor, a luz é refletida fora da interface prisma-metal em um fotodetetor. A luz refletida terá uma alta intensidade, exceto em um certo ângulo, relacionada às propriedades eletrônicas da superfície metálica, conhecida como "ângulo de ressonância plasmon superficial".
À medida que as moléculas se ligam à superfície, as propriedades eletrônicas do metal mudam, o que por sua vez ajusta o ângulo. À medida que novas proteínas se anexam, formando complexos, o ângulo mudará ainda mais. Medindo mudanças relativas no ângulo SPR, interações como essas podem ser monitoradas em tempo real.
Outra técnica chamada localização, ou "L"SPR, usa nanopartículas metálicas como superfície do sensor. As propriedades que afetam o ângulo SPR são altamente localizadas a cada nanopartícula, o que melhora a sensibilidade e a resolução do sinal.
Ao investigar interações de ligação com o SPR padrão, o sensor é geralmente montado em uma plataforma que se torna o chão de uma célula de fluxo no instrumento. As biomoléculas de interesse são transportadas através da célula de fluxo por solução tampão. A superfície do sensor é frequentemente revestida pela primeira vez com um substrato que tem uma alta afinidade com o metal. Isso garante que uma quantidade significativa de ligante, que por sua vez se liga ao analito de interesse, será imobilizada no sensor e reduz a probabilidade de que o ligante se dissociará durante o procedimento.
Uma vez que o ligante é imobilizado no sensor, o analito é fluído sobre o sensor em buffer. Monitorando a alteração no ângulo SPR ao longo do tempo à medida que o analito se liga ao ligante, a taxa de vinculação e outras informações cinéticas podem ser calculadas.
Os dados de reflectância também podem ser usados para imagens spr, ou SPRi, direcionando a luz refletida para um detector de CCD. Isso produz uma imagem de alto contraste e alta resolução de toda a superfície do sensor. Utilizando SPR e as técnicas relacionadas, as perguntas podem ser respondidas sobre afinidade molecular, cinética, especificidade e concentração.
Agora que você entende o que está sendo medido em um experimento spr, vamos olhar para um procedimento para investigar taxas vinculantes.
</div>
<div class="chapter_text" id="script_2">
Antes de iniciar o procedimento, os buffers de corrida e amostra devem ser preparados. O buffer de execução é usado para depositar o ligante no sensor, e o buffer de amostra é usado para depositar o analito. O chip do sensor é cuidadosamente limpo e carregado em uma baia. Em seguida, o dispositivo é colocado no instrumento, onde se torna a parte inferior da célula de fluxo. O software de instrumentos está configurado para o experimento e análise subsequente. Se necessário, a superfície do sensor é preparada com um substrato para capturar o ligante. O ligante é fluído sobre a superfície do sensor no buffer de corrida, onde é capturado pelo substrato na superfície do sensor.
Em seguida, o analito no tampão amostral é executado através da célula de fluxo, onde se liga seletivamente ao ligante imobilizado. A mudança na reflexão é plotada e comparada com os controles para determinar as constantes de taxa e outros dados de cinética de reação para a reação investigada.
</div>
<div class="chapter_text" id="script_3">
Agora que você entende como um experimento SPR é realizado, vamos olhar para algumas outras aplicações de SPR em bioquímica.
Aqui, a imagem SPR foi utilizada para avaliar proteínas com uma matriz de onze receptores em um sensor. Gráficos 3D de reflexividade versus tempo e concentração receptora foram preparados a partir dos dados de reflexividade de cada proteína. Esses "perfis" são característicos de cada proteína e, portanto, poderiam ser posteriormente utilizados para identificação de proteínas.
Neste experimento, secreções celulares foram estudadas usando um sensor LSPR personalizado. O sensor também era compatível com SPRi e microscopia de fluorescência. Ao depositar a célula no sensor, a interação das secreções celulares com a matriz de nanopartículas poderia ser medida com alta resolução espacial.
Aqui, foi investigado o uso de pontos quânticos, semicondutores nanoescala, como agente de aprimoramento de sinal SPR misturado com o analito. Este método aprimorado "nano-SPRi" foi comparado aos ensaios do SPRi padrão e do método ELISA. O método nano-SPRi melhorou significativamente a sensibilidade e o limite de detecção, sendo ainda menos demorado do que o método ELISA.
</div>
<div class="chapter_text" id="script_4">
Você acabou de ver o vídeo de JoVE sobre ressonância de plasmon superficial. Este fenômeno é usado para monitorar e imagem de interações biomoleculares sem o uso de rótulos. Este vídeo introduziu os princípios do SPR, um protocolo típico para a realização de um experimento spr, e algumas aplicações de SPR em bioquímica.
Obrigado por assistir!
</div>

Ressonância de Plasmons de Superfície (SPR)

Surface plasmon resonance (SPR) is the underlying optical phenomenon behind label-free biosensors to evaluate the molecular affinity, kinetics, ...

A ressonância plasmônica de superfície, ou SPR, é o fenômeno subjacente por trás de certos biossensores sem rótulo para avaliar as interações de ligação e adsorção de biomoléculas. Ensaios de ligação que requerem rotulagem, como ELISA, podem ser um processo demorado e podem alterar a funcionalidade do analito. Na SPR, as interações biomoleculares ocorrem em um sensor especial feito de uma fina camada de metal em uma face de um prisma. Ao monitorar as mudanças na luz refletida na parte inferior do metal, os instrumentos SPR visualizam essas interações em tempo real sem o uso de rótulos. Este vídeo apresentará os princípios da SPR, um procedimento geral para imagens de SPR e algumas aplicações em bioquímica. Um sensor SPR geralmente é feito de uma fina camada de um metal nobre no topo de um prisma. Para fazer leituras do sensor, a luz é refletida da interface prisma-metal para um fotodetector. A luz refletida terá uma alta intensidade, exceto em um determinado ângulo, relacionado às propriedades eletrônicas da superfície do metal, conhecido como "ângulo de ressonância plasmônica de superfície". À medida que as moléculas se ligam à superfície, as propriedades eletrônicas do metal mudam, o que, por sua vez, ajusta o ângulo. À medida que novas proteínas se ligam, formando complexos, o ângulo muda ainda mais. Ao medir mudanças relativas no ângulo SPR, interações como essas podem ser monitoradas em tempo real. Outra técnica chamada localizada, ou "L"SPR, usa nanopartículas metálicas como superfície do sensor. As propriedades que afetam o ângulo SPR são altamente localizadas em cada nanopartícula, o que melhora a sensibilidade e a resolução do sinal. Ao investigar as interações de ligação com o SPR padrão, o sensor geralmente é montado em uma plataforma que se torna o piso de uma célula de fluxo no instrumento. As biomoléculas de interesse são transportadas através da célula de fluxo por solução tampão. A superfície do sensor geralmente é revestida primeiro com um substrato que tem alta afinidade com o metal. Isso garante que uma quantidade significativa de ligante, que por sua vez se liga ao analito de interesse, seja imobilizada no sensor e reduz a probabilidade de que o ligante se dissocie durante o procedimento. Uma vez que o ligante é imobilizado no sensor, o analito é fluído sobre o sensor no buffer. Ao monitorar a mudança no ângulo SPR ao longo do tempo à medida que o analito se liga ao ligante, a taxa de ligação e outras informações cinéticas podem ser calculadas. Os dados de refletância também podem ser usados para imagens SPR, ou SPRi, direcionando a luz refletida para um detector CCD. Isso produz uma imagem de alto contraste e alta resolução de toda a superfície do sensor. Usando SPR e as técnicas relacionadas, perguntas podem ser respondidas sobre afinidade molecular, cinética, especificidade e concentração. Agora que você entende o que está sendo medido em um experimento SPR, vamos examinar um procedimento para investigar as taxas de ligação. Antes de iniciar o procedimento, os buffers de execução e de amostra devem ser preparados. O buffer de execução é usado para depositar o ligante no sensor e o buffer de amostra é usado para depositar o analito. O chip do sensor é cuidadosamente limpo e carregado em uma bainha. Em seguida, o dispositivo é colocado no instrumento, onde se torna o fundo da célula de fluxo. O software do instrumento é configurado para o experimento e análise subsequente. Se necessário, a superfície do sensor é preparada com um substrato para capturar o ligante. O ligante flui sobre a superfície do sensor no buffer de execução, onde é capturado pelo substrato na superfície do sensor. Em seguida, o analito no tampão de amostra é executado através da célula de fluxo, onde se liga seletivamente ao ligante imobilizado. A mudança na refletância é plotada e comparada com os controles para determinar as constantes de taxa e outros dados cinéticos de reação para a reação investigada. Agora que você entende como um experimento de SPR é realizado, vejamos algumas outras aplicações de SPR em bioquímica. Aqui, a imagem SPR foi usada para avaliar proteínas com uma matriz de onze receptores em um sensor. Gráficos 3D de refletividade versus tempo e concentração do receptor foram preparados a partir dos dados de refletividade para cada proteína. Esses "perfis" são característicos de cada proteína e, portanto, podem ser usados posteriormente para identificação de proteínas. Neste experimento, as secreções celulares foram estudadas usando um sensor LSPR feito sob medida. O sensor também era compatível com SPRi e microscopia de fluorescência. Ao depositar a célula no sensor, a interação das secreções celulares com a matriz de nanopartículas pode ser medida com alta resolução espacial. Aqui, foi investigado o uso de pontos quânticos, semicondutores em nanoescala, como um agente de aprimoramento de sinal SPR misturado com o analito. Este método "nano-SPRi" aprimorado foi comparado aos ensaios pelo SPRi padrão e pelo método ELISA. O método nano-SPRi melhorou significativamente a sensibilidade e o limite de detecção, embora ainda seja menos demorado do que o método ELISA. Você acabou de assistir ao vídeo de JoVE sobre ressonância plasmônica de superfície. Este fenômeno é usado para monitorar e visualizar interações biomoleculares sem o uso de rótulos. Este vídeo apresentou os princípios do SPR, um protocolo típico para a realização de um experimento de SPR, e algumas aplicações do SPR em bioquímica. Obrigado por assistir!

Education

JoVE Science Education

Chemistry

Química

Biochemistry

Bioquímica

spr biosensors for tracking binding kinetics

Surface plasmon resonance, or SPR, is a way to track biomolecular binding on a label-free biosensor. It is used to measure molecular affinity, kinetics, specificity, and concentration. The method works with a thin metal layer on a prism, where changes in reflected light reveal interactions in real time.

SPR sensors use a thin layer of a noble metal on the face of a prism. Light is reflected from the prism-metal interface into a photodetector. At one specific angle, called the surface plasmon resonance angle, the reflected light drops in intensity. When molecules bind to the metal surface, the electronic properties change and the angle shifts. As more proteins attach and form complexes, the shift becomes larger.

A related method, localized SPR, or LSPR, uses metal nanoparticles as the sensor surface. Because the sensing effect is highly local around each nanoparticle, LSPR can improve sensitivity and signal resolution. SPR data can also be turned into images with SPR imaging, or SPRi, by sending the reflected light to a CCD detector. This creates a high-contrast, high-resolution image of the full sensor surface.

For a standard SPR binding assay, the sensor is mounted in a platform that forms the floor of a flow cell. Biomolecules are carried through the flow cell in buffer solution. The sensor surface is often coated first with a substrate that binds the metal well. This helps immobilize the ligand, which is the molecule that will capture the analyte, and lowers the chance that the ligand will dissociate during the run. After the ligand is attached, the analyte is flowed over the sensor in buffer, and the change in SPR angle is recorded over time to calculate binding rates and other kinetic data.

Before the experiment begins, the running buffer and sample buffer must be prepared. The running buffer is used to deposit the ligand onto the sensor, and the sample buffer is used to deposit the analyte. The sensor chip is cleaned, loaded into a sheath, and placed into the instrument. The software is then set up for data collection and analysis. If needed, the surface is primed with a capture substrate. The ligand is then captured, the analyte is run through the flow cell, and the reflectance change is compared with controls to determine rate constants and other reaction kinetics.

SPR is also useful in several biochemistry applications. In one SPR imaging example, proteins were tested with an array of eleven receptors on a sensor, and 3D graphs of reflectivity versus time and receptor concentration were made for each protein. These reflectivity profiles were characteristic of each protein and could be used for identification. In another study, cell secretions were measured with a custom LSPR sensor that also worked with SPRi and fluorescence microscopy. A further application used quantum dots, which are nanoscale semiconductors, to enhance the SPR signal in a method called nano-SPRi. Compared with standard SPRi and ELISA, nano-SPRi improved sensitivity and the limit of detection while still taking less time than ELISA.

SPR Biosensors for Tracking Binding Kinetics

dialysis: diffusion based separation

Dialysis for Buffer Exchange in Biochemistry

Dialysis is a common biochemistry technique for buffer exchange and desalting. It separates molecules by diffusion through a semipermeable membrane, which lets small molecules pass while holding larger biomolecules inside the sample. The membrane is the key part of the setup. Its pores create a molecular weight cutoff, so a membrane such as a 10 kDa membrane usually keeps molecules larger than 10 kilodaltons inside. This cutoff is not exact, because membranes have a range of pore sizes.

enzyme assays and kinetics

Measuring Enzyme Reaction Rates

Enzyme reaction rates can be measured with assays that track how substrate or product levels change over time. Enzymes are proteins, or sometimes RNAs, that speed up chemical reactions by lowering the activation energy needed to start them. They act on a specific substrate and help form a product that supports life processes. Enzymatic reactions are often described in three steps. First, the substrate binds to the enzyme active site and forms an enzyme-substrate complex. That complex can fall...

maldi-tof mass spectrometry

How MALDI-TOF Reads Biomolecules

MALDI-TOF mass spectrometry reads biomolecules by using a laser, a matrix, and a time-of-flight analyzer. MALDI, or matrix-assisted laser desorption ionization, helps fragile molecules keep their structure while they are moved into the mass analyzer. The analyzer then separates compounds based on size and charge. In MALDI, the sample is mixed into a matrix, usually an organic compound with aromatic and conjugated double bonds. A laser pulse strikes the spot, and the matrix absorbs most of the...

tandem mass spectrometry

Tandem Mass Spectrometry for Biomolecule Analysis

Tandem mass spectrometry is used to isolate a biomolecule and break it into smaller pieces so its makeup can be studied. Because biomolecules often have large, complex structures, it can be hard to identify their molecular composition and sequence from a single measurement. By linking mass spectrometers in series, the technique first selects one ion and then analyzes the fragments it produces. The process starts with an ion source that converts the sample into ions. A mass analyzer then...

protein crystallization

Protein Crystals for Structure Analysis

Protein crystals help scientists study protein structure and function. A crystal is a solid lattice made from purified protein molecules. These crystals are useful in structural biology because they reveal details that methods like mass spectrometry and SDS-PAGE cannot show on their own. Protein crystallization is paired with recombinant protein expression and x-ray diffraction to support this work. The process starts with a large amount of very pure protein. Researchers often make that...

chromatography-based biomolecule purification methods

chromatography-based-biomolecule-purification-methods

Protein Purification with SEC and IMAC

Protein purification with size-exclusion chromatography and affinity chromatography helps isolate biomolecules from complex mixtures. These methods are common in biochemistry because purified samples are needed before a biomolecule’s properties and activity can be studied. The video focuses on the principles behind size-exclusion chromatography, affinity chromatography, and immobilized metal affinity chromatography, or IMAC. Size-exclusion chromatography, or SEC, separates molecules by size. A...

two-dimensional gel electrophoresis

Protein Mapping with 2D Gel Electrophoresis

Protein mapping with 2D gel electrophoresis separates complex protein mixtures across two steps. The method combines isoelectric focusing, or IEF, with sodium dodecyl sulfate polyacrylamide gel electrophoresis, or SDS-PAGE. Together, these methods can resolve thousands of biomolecules from a single sample by their isoelectric point and molecular weight. The first dimension is IEF. Each protein has an isoelectric point, or pI, which is the pH where its net charge is zero. Proteins are loaded...

metabolic labeling

Tracking Cell Chemistry with Metabolic Labels

Metabolic labeling tracks cell chemistry by using chemical analogs that cells take up and build into biomolecules. These labels help scientists follow biochemical changes and modifications inside cells. The labeled products can then be studied with tools such as SDS-PAGE and NMR to learn more about metabolic pathways. Several labeling strategies are shown here. Isotopic labeling uses analogs that match the natural molecule but contain uncommon isotopes, such as carbon-13 and nitrogen-15 in an...

electrophoretic mobility shift assay (emsa)

electrophoretic-mobility-shift-assay-emsa

Detecting Protein-DNA Binding by EMSA

Electrophoretic mobility shift assay, or EMSA, is a biochemical method used to detect binding between proteins and nucleic acids. It is also called a gel shift assay. The test compares how a labeled nucleic acid moves through a gel before and after it binds a protein. EMSA is used to see whether a specific protein binds to a specific nucleic acid. First, the nucleic acid is labeled to make a probe. The transcript describes radioactive phosphorus-32 as a common label. The probe is then mixed...

photometric protein determination

Measuring Protein Concentration with Absorbance

Measuring protein concentration with absorbance is a key step in many biochemical assays. Photometric methods use the fact that samples with more light-absorbing material transmit less light. Because concentration and absorption are directly related, this makes it possible to measure an unknown sample. The core idea comes from the Beer-Lambert Law. This law states that the concentration of a light-absorbing species is proportional to its absorbance. The video also introduces the Bradford assay...

density gradient ultracentrifugation

Sucrose Gradient Separation in an Ultracentrifuge

Sucrose gradient separation in an ultracentrifuge is a lab method for isolating cell parts and biomolecules. It uses differences in density to make particles sink or rise in a liquid. A high-speed ultracentrifuge speeds up this process so components can be separated without destroying them. The basic idea starts with a suspension, which is particles mixed in a liquid solvent. Particles that are denser than the solvent sediment, while less dense particles float. A rotor inside the...

co-immunoprecipitation and pull-down assays

co-immunoprecipitation-and-pull-down-assays

Protein Interaction Capture Methods in Cells

Co-immunoprecipitation and pull-down assays are laboratory methods used to capture stable protein-protein interactions. Protein-protein interactions help control many biological functions, but many of them have not yet been identified. These assays are related to immunoprecipitation, which isolates a target protein from a mixed sample using an antibody. In co-immunoprecipitation, or CoIP, an antibody binds the target protein, and that protein is already attached to another protein that the...

reconstitution of membrane proteins

Membrane Proteins in Liposome Models

Membrane proteins can be moved into liposome models so their function can be studied outside a cell. Reconstitution means restoring an isolated biomolecule to a working form. For membrane proteins, that usually means placing a purified protein into an artificial lipid membrane. Cell membranes are made mainly of phospholipids and membrane proteins. The phospholipids form a bilayer with hydrophilic phosphate heads facing water and hydrophobic fatty acid tails facing inward. Some membrane...

f&#246;rster resonance energy transfer (fret)

FRET as a Molecular Ruler in Cells

Föster resonance energy transfer, or FRET, is a way to study close-range biochemical interactions using light-emitting molecules. A donor fluorophore can pass energy to an acceptor fluorophore when their emission and absorption spectra overlap. This transfer happens only when the pair is very close together, usually within 10 nm. Because FRET depends on distance, it is often called a molecular or spectroscopic ruler. The strength of the signal is measured as FRET efficiency, which describes...

surface plasmon resonance (spr)

Surface plasmon resonance, or SPR, is a way to track biomolecular binding on a label-free biosensor. It is used to measure molecular affinity, kinetics, specificity, and concentration. The method works with a thin metal layer on a prism, where changes in reflected light reveal interactions in real time. SPR sensors use a thin layer of a noble metal on the face of a prism. Light is reflected from the prism-metal interface into a photodetector. At one specific angle, called the surface plasmon...

biochemistry

Esta coleção apresenta métodos de purificação comumente usados, como cromatografia de afinidade, bem como métodos analíticos, como MALDI-TOF. Além disso, os vídeos mostram métodos para avaliar a interação e função de biomoléculas, como coimunoprecipitação e marcação metabólica.

Explore how SPR biosensors track biomolecular binding in real time, measure kinetics, and support imaging methods such as SPRi and LSPR.

SPR Biosensors for Tracking Binding Kinetics | JoVE K12

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Waves and Electromagnetic Radiation

HS-PS4-5.

Life Science

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

HS-LS1-6.

Overview

Principles of SPR

SPR Sample Preparation and Experimental Protocol

Applications

Summary

Travelling Waves

A wave is a disturbance that propagates from its source, repeating itself periodically, and is typically associated with simple harmonic motion. ...

Wave Parameters

The simplest mechanical waves are associated with simple harmonic motion and repeat themselves for several cycles. These simple harmonic waves can be ...

Equations of Wave Motion

Mathematically, the motion of a wave can be studied using a wavefunction. Consider a string oscillating up and down in simple harmonic motion, having a ...

Graphing the Wave Function

Consider the wave equation for a sinusoidal wave moving in the positive x-direction. The wave equation is a function of both position and time. From the ...

/files/media/science-education/science-education-thumbs/14721.jpg

Velocity and Acceleration of a Wave

A wave propagates through a medium with a constant speed, known as a wave velocity. It is different from the speed of the particles of the medium, which ...

Speed of a Transverse Wave

The speed of a wave depends on the characteristics of the medium. For example, in the case of a guitar, the strings vibrate to produce the sound. The ...

/files/media/science-education/science-education-thumbs/14722.jpg

Kinetic and Potential Energy of a Wave

All forms of waves carry energy; this is directly visualized in nature. For instance, the waves of earthquakes are so intense that they can shake huge ...

Energy and Power of a Wave

The total energy associated with a wavelength is the sum of the potential energy and the kinetic energy. The average rate of energy transfer associated ...

Propagation of Waves

When a wave propagates from one medium to another, part of it may get reflected in the first medium, and part of it may get transmitted to the second ...

Sound Waves

Sound waves can be thought of as fluctuations in the pressure of a medium through which they propagate. Since the pressure also makes the medium&#39;s ...

Sound as Pressure Waves

Sound waves, which are longitudinal waves, can be modeled as the displacement amplitude varying as a function of the spatial and temporal coordinates. As ...

/files/media/science-education/science-education-thumbs/14724.jpg

Speed of Sound in Solids and Liquids

Most solids and liquids are incompressible&#8212;their densities remain constant throughout. In the presence of an external force, the molecules tend to ...

Speed of Sound in Gases

The speed of sound in a gaseous medium depends on various factors. Since gases constitute molecules that are free to move, they are highly compressible. ...

Doppler Effect - I

The Doppler effect and Doppler shift were named after the Austrian physicist and mathematician Christian Johann Doppler in 1842, who conducted experiments ...

Doppler Effect - II

The Doppler effect has several practical, real-world applications. For instance, meteorologists use Doppler radars to interpret weather events based on ...

Shock Waves

While deriving the Doppler formula for the observed frequency of a sound wave, it is assumed that the speed of sound in the medium is greater than the ...

Echo

The human ear cannot distinguish between two sources of sound if they happen to reach within a specific time interval, typically 0.1 seconds apart. More ...

/files/media/science-education/science-education-thumbs/14729.jpg

Electromagnetic Waves

James Clerk Maxwell formulated a single theory combining all the electric and magnetic effects scientists knew during that time, calling the phenomena his ...

Generating Electromagnetic Radiations

The German physicist Heinrich Hertz (1857&#8211;1894) was the first to generate and detect certain types of electromagnetic waves in the laboratory. ...

Electromagnetic Wave Equation

Maxwell&#39;s equations for electromagnetic fields are related to source charges, either static or moving. These fields act on a test charge, whose ...

propagation-speed-of-electromagnetic-waves

Propagation Speed of Electromagnetic Waves

Electromagnetic waves are consistent with Ampere&#39;s law. Assuming there is no conduction current Ampere&#39;s law is given as:


Consider a plane ...

Electromagnetic Waves in Matter

Electromagnetic waves can travel in the vacuum as well as in matter. For example light, which is an electromagnetic wave, can travel through air, water, ...

Energy Carried By Electromagnetic Waves

Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes, this energy is obvious, such as in the summer sun&#39;s ...

The Wave Nature of Light

The nature of light has been a subject of inquiry since antiquity. In the seventeenth century, Isaac Newton performed experiments with lenses and prisms ...

Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling in various media. [Clarification Statement: Examples of data could include electromagnetic radiation traveling in a vacuum and glass, sound waves traveling through air and water, and seismic waves traveling through the earth.] [Assessment Boundary: Assessment is limited to algebraic relationships and describing those relationships qualitatively.]

HS-PS4-1

The Electromagnetic Spectrum

Electromagnetic waves are categorized according to their wavelengths and frequencies, giving the electromagnetic spectrum. These waves are classified as ...

Classification of Signals

Signals are categorized as Continuous-time or discrete-time, Periodic or aperiodic, Analog or digital, and Causal or noncausal.
A continuous-time signal ...

Discrete Fourier Transform

Consider a vibration sensor that continuously captures data in the form of a continuous time-dependent signal.
However, in reality, the sensor can only ...

Discrete-Time Fourier Series

The Discrete-Time Fourier Series is a counterpart to the Fourier-series expansion of continuous-time periodic signals.
Calculating the expansion ...

Sampling Theorem

Consider the continuous-time signal x(t), and a train of impulses where Ts,&#xA0; is the sampling interval, and fs, is the sampling frequency.
Multiplying ...

Properties of Fourier Transform I

In radio broadcasting, Fourier Transform properties are applied in simultaneous multi-channel transmission, adjusting audio clip speeds, live broadcast ...

Signal and System

Signals are sets of data or information.
One-dimensional signals include single-variable functions, such as the variations in air pressure over time in ...

Methods of Documentation VII: EMR

Electronic Medical Records (EMRs) primarily center around electronically documenting patients&#39; health information within a single healthcare ...

Fast Fourier Transform

The Fast Fourier Transform, FFT, is a computational algorithm for calculating the Discrete Fourier Transform by breaking the calculations into smaller, ...

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Reconstruction of Signal using Interpolation

Consider a continuous signal and its sampled counterpart with a sampling period T.
Applying a zero-order hold to the sampled signal results in a piecewise ...

Downsampling

Consider a sampled sequence with zero values between sampling instants. Replace it by taking every N-th value of the sampled sequence.
The original and ...

Design Example

An engineer designs a circuit for a speaker system with a 2 kHz crossover frequency requirement, considering the speaker&#39;s resistance of 8 ohms.
The ...

Upsampling

Consider a decimated signal with a reduced frequency range due to its lower sampling rate.
Insert zeros between each sample to upsample, that introduces ...

Properties of DTFT I

Consider two discrete-time signals, each with their respective Discrete-Time Fourier Transforms DTFTs.
The signals are first multiplied by constants a and ...

Relation of DFT to z-Transform

The Discrete Fourier Transform (DFT) analyzes the frequency content of discrete-time signals.
It maps the N-sampled discrete time-domain sequence to its ...

Feedback control systems

Feedback control systems are categorized as linear or nonlinear, time-varying or time-invariant, and classified by signal types as continuous or ...

Properties of the z-Transform I

Certain properties provide a solid foundation for analyzing discrete-time systems using the Z-transform.
Considering two discrete-time signals, the ...

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which ...

Evaluate questions about the advantages of using digital transmission and storage of information. [Clarification Statement: Examples of advantages could include that digital information is stable because it can be stored reliably in computer memory, transferred easily, and copied and shared rapidly. Disadvantages could include issues of easy deletion, security, and theft.]

HS-PS4-2

Interference and Superposition of Waves

When two waves of the same nature occur in the same region simultaneously, they result in interference. Interference of waves implies that the net effect ...

Sound Waves: Interference

Sound waves can be modeled either as longitudinal waves, wherein the molecules of the medium oscillate around an equilibrium position, or as pressure ...

Interference: Path Lengths

Consider two sources of sound, that may or may not be in phase, emitting waves at a single frequency, and consider the frequencies to be the same.
Two ...

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concept-of-resonance-and-its-characteristics

Concept of Resonance and its Characteristics

If a driven oscillator needs to resonate at a specific frequency, then very light damping is required. An example of light damping includes playing piano ...

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Sound Waves: Resonance

Resonance is produced depending on the boundary conditions imposed on a wave. Resonance can be produced in a string under tension with symmetrical ...

Reflection of Waves

When a wave travels from one medium to another, it gets reflected at the boundary of the second medium. A common example of this is when a person yells at ...

Standing Waves

Sometimes waves do not seem to move; rather, they just vibrate in place. Unmoving waves can be seen on the surface of a glass of milk kept in a ...

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Modes of Standing Waves - I

A close look at earthquakes provides evidence for the conditions appropriate for resonance, standing waves, and constructive and destructive interference. ...

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Evaluate the claims, evidence, and reasoning behind the idea that electromagnetic radiation can be described either by a wave model or a particle model, and that for some situations one model is more useful than the other. [Clarification Statement: Emphasis is on how the experimental evidence supports the claim and how a theory is generally modified in light of new evidence. Examples of a phenomenon could include resonance, interference, diffraction, and photoelectric effect.] [Assessment Boundary: Assessment does not include using quantum theory.]

HS-PS4-3

SPR Biosensors for Tracking Binding Kinetics

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