Nanotechnology Introduction and Applications
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Questions and Answers

What size range defines nanoparticles?

Nanoparticles are defined as being in the size range of 5 to 100 nm.

What is the purpose of the protective layer in nanoparticles?

The protective layer shields the functional layer from chemical damage and protects the cell from harmful components.

List two applications of nanoparticles in the biological arena.

Nanoparticles are used in fluorescent labeling and the delivery of pharmaceuticals.

What materials comprise luminescent CdSe nanorods?

<p>Luminescent CdSe nanorods consist of a core of cadmium selenide (CdSe) and an outer shell of zinc sulfide (ZnS).</p> Signup and view all the answers

How do nanoparticles enhance magnetic resonance imaging (MRI)?

<p>Nanoparticles enhance MRI by improving contrast, making the imaging clearer and more informative.</p> Signup and view all the answers

What is the benefit of having a hydrophobic layer on nanoparticles?

<p>A hydrophobic layer allows nanoparticles to achieve water solubility and biocompatibility.</p> Signup and view all the answers

What role do outer chemical groups play in the functionality of silica-coated nanorods?

<p>Outer chemical groups enable the attachment of nanorods to proteins, enhancing their application in biological systems.</p> Signup and view all the answers

Why is fluorescence a popular feature in the central functional layer of nanoparticles?

<p>Fluorescence is popular due to its useful optical properties that allow for effective labeling and detection techniques.</p> Signup and view all the answers

What is the significance of manipulating materials at the nanoscale?

<p>Manipulating materials at the nanoscale allows for the creation of components with novel properties and the enhancement of existing materials.</p> Signup and view all the answers

How does a scanning probe microscope differ from traditional microscopes?

<p>Scanning probe microscopes do not rely on lenses, meaning their resolution is limited by the probe size rather than diffraction.</p> Signup and view all the answers

What is the primary function of the scanning tunneling microscope (STM)?

<p>The STM measures electrical resistance by positioning a metal tip close to a conducting surface.</p> Signup and view all the answers

Can you explain how atomic force microscopes (AFM) operate?

<p>AFMs measure the force between the probe tip and the sample, allowing for imaging and measuring surface properties at the nanoscale.</p> Signup and view all the answers

In what ways has nanotechnology expanded beyond its original goals?

<p>Nanotechnology now includes studying and manipulating any tiny structures previously beyond observation, applying it to areas beyond just material science.</p> Signup and view all the answers

Why are quantum effects important to the study of nanotechnology?

<p>Quantum effects influence the properties and behaviors of materials at the nanoscale, which are not observable at larger scales.</p> Signup and view all the answers

What are the two main types of scanning probe instruments mentioned, and their primary measurements?

<p>The two main types are the scanning tunneling microscope (STM), which measures electrical resistance, and the atomic force microscope (AFM), which measures force.</p> Signup and view all the answers

Describe a practical application of nanobiotechnology.

<p>Nanobiotechnology can be applied in drug delivery systems that utilize nanoscale materials to target specific cells in medical treatments.</p> Signup and view all the answers

How do nanotubes contribute to photothermal killing of cancer cells?

<p>Nanotubes absorb near infrared radiation and generate local heating, leading to cell death.</p> Signup and view all the answers

What role do linker molecules play in drug delivery using nanotubes?

<p>Linker molecules connect the surface of the nanotube to the drug, allowing for targeted delivery without encapsulation.</p> Signup and view all the answers

Describe how nanotubes can be used for tissue regeneration.

<p>Nanotubes can act as scaffolds for regenerating tissues when functionalized with appropriate chemical groups.</p> Signup and view all the answers

What phenomenon occurs when a hole and an electron recombine in nanoparticles?

<p>Light is emitted when a hole and an electron recombine.</p> Signup and view all the answers

How can nanoparticles be utilized for targeted drug delivery?

<p>Nanoparticles can target specific tissues to deliver drugs, DNA, or RNA.</p> Signup and view all the answers

What is the function of antibacterial nanocarpets?

<p>Antibacterial nanocarpets are surfaces made from assembled nanotubes that prevent bacterial growth.</p> Signup and view all the answers

What is one method nanoparticles use to kill cancer cells through localized heating?

<p>Localized heating is achieved using a magnetic core under magnetic field or metal nanoshells absorbing near-infrared radiation.</p> Signup and view all the answers

How do nanowire sensors detect viruses?

<p>Nanowire sensors detect viruses by measuring changes in conductance when a virus particle binds to the wire.</p> Signup and view all the answers

Explain the purpose of nanoscale ion channels.

<p>Nanoscale ion channels allow controlled movement of ions, generating electrical currents for detecting target molecules.</p> Signup and view all the answers

Describe the role of singlet oxygen in nanoparticle-assisted cancer therapy.

<p>Singlet oxygen is generated from normal oxygen when nanoparticles transfer energy to photosensitizers.</p> Signup and view all the answers

What is the primary benefit of using a rigid DNA component in constructing nanoscale frameworks?

<p>A rigid DNA component, such as double-crossover (DX) DNA molecules, helps create junctions that are less flexible and maintain structural integrity at 90° angles.</p> Signup and view all the answers

How do gold nanoparticles contribute to preventing blood vessel formation in cancer therapy?

<p>Gold nanoparticles with short surface peptides bind to receptors involved in angiogenesis.</p> Signup and view all the answers

What is the primary goal of nanoengineering of DNA?

<p>The primary goal is to use DNA as a structural material instead of manipulating genetic information.</p> Signup and view all the answers

How does the DNA origami approach simplify the assembly of DNA nanostructures compared to traditional methods?

<p>The DNA origami approach uses a single long DNA strand folded into a scaffold, eliminating the need for strict control over the ratios of different DNA strands.</p> Signup and view all the answers

How can branched DNA be utilized in creating 3D structures?

<p>Branched DNA can form cross-shaped structures that can be linked together to create 3D DNA lattices.</p> Signup and view all the answers

What unique ability do certain bacteria, like E. coli, possess regarding metallic elements?

<p>Certain bacteria can biosynthesize semiconductor nanocrystals by modifying metallic elements.</p> Signup and view all the answers

What role do staple strands play in the DNA origami technique?

<p>Staple strands bind to specific sites along the longer scaffold strand, assisting in the folding process of the DNA origami structure.</p> Signup and view all the answers

What is the purpose of using chitosan nanocarriers in drug delivery systems?

<p>Chitosan nanocarriers interact strongly with mucosal surfaces to enhance drug delivery.</p> Signup and view all the answers

What limitation is associated with building complex nanostructures using multiple DNA molecules?

<p>Building complex nanostructures with multiple DNA molecules becomes challenging beyond a certain complexity due to difficulties in controlling ratios and interactions.</p> Signup and view all the answers

What is the size range of cadmium sulfide particles precipitated by E. coli when exposed to certain chemicals?

<p>Cadmium sulfide particles are typically in the size range of 2-5 nm.</p> Signup and view all the answers

In what way can computer-aided design enhance the DNA origami process?

<p>Computer-aided design can be used to specify the required DNA sequence, facilitating the creation of specific desired forms in DNA origami.</p> Signup and view all the answers

What is the primary function of a scanning tunneling microscope (STM) in studying surfaces?

<p>The primary function of STM is to detect individual atoms on a surface and map its contours with high resolution.</p> Signup and view all the answers

How does atomic force microscopy (AFM) differ from STM in terms of surface interaction?

<p>AFM involves a sharp probe that bends in response to forces between the tip and the sample, whereas STM relies on tunneling current between the tip and conducting surfaces.</p> Signup and view all the answers

What role do piezoelectric ceramics play in atomic force microscopy?

<p>Piezoelectric ceramics are used to precisely control the positioning and movement of the AFM tip during scanning.</p> Signup and view all the answers

What technology is used in AFM to monitor the displacement of the cantilever?

<p>A laser is used to monitor the displacement of the cantilever by reflecting off its surface and being collected by a position-sensitive detector.</p> Signup and view all the answers

How can AFM help visualize biological molecules like DNA?

<p>AFM can visualize polymeric biological molecules by scanning their surface and providing high-resolution images of their composition.</p> Signup and view all the answers

Describe how the oscillation frequency of a cantilever is affected when a microorganism is added.

<p>The addition of a microorganism to the cantilever modifies its oscillation frequency, allowing for the deduction of the organism's mass.</p> Signup and view all the answers

What is the significance of using an antibody in the AFM mass measurement process?

<p>An antibody is used to immobilize the bacteria or virus on the cantilever, ensuring accurate mass measurement.</p> Signup and view all the answers

What high-resolution capability does STM provide that is essential for nanotechnology?

<p>STM provides the capability to render surface contours at an atomic level, detecting each individual atom.</p> Signup and view all the answers

Study Notes

Nanotechnology Introduction

  • Nanometers are 10-9 meters
  • Nanotechnology manipulates single molecules/atoms to create materials with improved properties
  • The original goal focused on atom-by-atom or molecule-by-molecule construction
  • Now includes any structure too small to be easily manipulated
  • Quantum effects are considered at this scale
  • Biological components are on the same scale as the components studied in nanotechnology
  • Nanotechnology is also seen as a perspective for molecular biology as a material science
  • Main objectives of nanobiotechnology include using biological components for nanoscale tasks
  • These tasks have applications in electronics, computing, and biology/medicine

Visualization at the Nano-scale

  • Scanning probe microscopes opened up nanotechnology by allowing individual atom/molecule visualization
  • It measures a property with a tip near the sample (electrical resistance, magnetism, etc)
  • The microscope raster-scans the probe and the resulting data are displayed as an image (similar to a television screen)
  • Unlike other microscopes, scanned probe systems are not limited by diffraction; resolution is determined by the probe size
  • Some scanning probe instruments have visualization and sample alteration capabilities
  • Scanning Tunneling Microscopes (STM) measure electrical resistance
  • Atomic Force Microscopes (AFM) measure the force between the tip and the sample

Scanning Tunneling Microscopy

  • A metal tip comes close enough to a conducting surface that electrons can tunnel
  • The probability of tunneling depends on the distance between the tip and the sample
  • By keeping the current constant and measuring the tip height, surface contours can be mapped

Atomic Force Microscopy

  • A sharp probe moves across the sample surface, bending in response to the force between tip and sample
  • The probe's movement creates a topographical image
  • The positioning/movement is done with a piezoelectric ceramic device
  • The AFM probe is a tip on a cantilever
  • A laser beam monitors cantilever displacement, which is then used to create the image
  • It can visualize polymeric biological molecules, DNA, and cellulose at high resolution

Weighing Single Bacteria and Virus Particles

  • Laser frequency oscillations can be used to measure the mass of an object
  • An antibody is used to immobilize bacteria/viruses on the cantilever

Nanoparticles and Their Uses

  • Nanoparticles are typically 5 to 100 nm in size
  • Often spherical, but can be rods, plates, etc
  • May be solid or hollow
  • Can be composed of various materials arranged in layers for different functions
  • Central functional layer: for optical/magnetic properties (e.g., fluorescence)
  • Protective layer: shields the functional layer from damage
  • Outer layers: allow biocompatibility (water solubility) and specific recognition

Nanoparticles for Labeling

  • Luminescent CdSe nanorods are used for fluorescent labeling
  • A cadmium selenide (CdSe) core is used, and a zinc sulfide (ZnS) outer shell is used as a protective layer
  • An outer silica layer facilitates attaching other molecules
  • Nanorods can mimic native tubulin and form fluorescent microtubules

Quantum Size Effect and Nanocrystal Colors

  • Quantum dots are semiconductors small enough to show quantum effects
  • They can be n-type or p-type semiconductors, allowing for specific conditions of electrical conduction
  • Electron-hole pair formation and energy release depend on particle size
  • Light is emitted when an electron and a hole recombine

Nanoparticles for Delivery of Drugs, DNA, or RNA

  • Nanoparticles can target tissues by adding appropriate antibodies or receptor proteins to their surface
  • They can deliver biologically active molecules such as drugs, DNA, and RNA
  • Fluorescent nanoparticles, also known as quantum dots, are more versatile than fluorescent dyes
  • Can label PCR primers for quantum dot PCR

Nanoparticles in Cancer Therapy

  • Nanoparticles can be used to kill cancer cells by localized heating or creating toxic products
  • Near-infrared lasers are used to heat up metal nanoparticles or stimulate reactions

Assembly of Nanocrystals by Microorganisms

  • Bacteria can accumulate/modify metallic elements, creating nanocrystals
  • Bacteria such as E. coli can produce cadmium sulfide (CdS) nanocrystals

Nanotubes

  • Cylinders of pure carbon (1-50 nm in diameter, up to 10 mm long)
  • Other forms are diamond and graphite
  • Can be metallic conductors or semiconductors
  • Single-walled carbon nanotubes are commonly used in biotechnology
  • Attaching molecules (e.g., enzymes, antibodies) to the nanotubes is important

DNA Origami

  • Nanostructures assembled using multiple DNA molecules
  • DNA origami uses one long "scaffold" strand and multiple "staple" strands to drive folding
  • It simplifies nanostructure assembly and doesn't need precise ratios of different DNA strands
  • Computer-aided design is used to determine necessary DNA sequences

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Lecture 12 - Nanotechnology PDF

Description

Explore the fascinating world of nanotechnology, where materials are manipulated at the molecular level to enhance their properties. This quiz covers the fundamentals of nanotechnology, including its applications in electronics, biology, and medicine, as well as the role of visualization techniques like scanning probe microscopy. Test your knowledge on the principles and objectives of nanobiotechnology and its implications for future innovations.

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