Lab 2: Smartphone-based NP detection Flashcards
(22 cards)
What are nanoplastics, and why are they a concern?
Nanoplastics are tiny plastic particles (<1 μm) that accumulate in the environment, posing risks to ecosystems and human health.
Why is a smartphone-based fluorescence microscope useful for detecting nanoplastics?
It provides a portable, cost-effective, and rapid alternative to traditional microscopy methods.
What is fluorescence, and how is it used in this experiment?
Lab 2: Smartphone NP Detection
Fluorescence occurs when a molecule absorbs light and emits it at a different wavelength. In this experiment, labeled nanoplastics emit fluorescence that is detected by the smartphone microscope.
What role do metal-phenolic networks (MPNs) play in this experiment?
Lab 2: Smartphone NP Detection
Rhodamine B = Fluorescent dye within the L-MPN structure.
It enables detection by emitting fluorescence when exposed to specific light (from the LED).
The L-MPN (Tannic acid + Zr⁴⁺ + RhB) binds to nanoplastics, and after washing off excess dye, only labeled NPs fluoresce for clear imaging.
Luminescent Metal-Phenolic Networks
L-MPNs interact with NPs through pi-interactions and coordination bonding, allowing them to fluoresce under specific lighting.
What is the function of Rhodamine B in the labeling process?
Rhodamine B is a fluorescent dye that binds to nanoplastics, allowing them to be visualized under the microscope.
It is a fluorescent probe that binds NPs, enabling visualization.
Why is vortexing necessary when preparing L-MPN labeled nanoplastics?
To ensure homogenous mixing of the labeling reagents.
How are nanoplastics detected in this experiment?
Labeled nanoplastics are placed on a nitrocellulose membrane, dried, and then imaged using a smartphone-based microscope.
What software is used for image processing in this experiment?
Smartphone-based NP detection
MATLAB is used to analyze fluorescence intensity and quantify nanoplastics.
How is the concentration of nanoplastics determined?
By measuring pixel area in the fluorescence images and using a standard curve equation.
Why is it important to remove unreacted Rhodamine B before analysis?
To avoid interference from free dye, which could give false-positive signals.
How is the number of nanoplastics quantified from fluorescence images?
By comparing pixel area of fluorescence to a standard curve
What is the significance of confocal laser scanning microscopy (CLSM) in this lab?
Smartphone-based NP detection
It provides high-resolution images of labeled NPs to confirm fluorescence labeling.
How does the smartphone-based microscope detect nanoplastics?
The microscope captures fluorescent images of labeled nanoplastics, which are analyzed for their intensity and pixel area.
What is the function of the emission filter in the smartphone microscope?
It filters out unwanted light, allowing only fluorescence with a center wavelength of 591.5 nm to be detected.
What is the excitation wavelength range of the green LED in the smartphone-based microscope?
535 to 558 nm
What are MPNs and what are their advantages?
- Supramolecular structures formed by metal ions and phenolic ligands, used for labelling and detecting nanoplastics.
- They are rapid, simple, widely applicable, and allow for trapping & separation of nanoplastics.
What is an extrinsic fluorescence probe?
A fluorescent probe added to a sample to enhance detection, typically small, stable, and has a specific binding site.
Why is intrinsic fluorescence not always suitable for nanoplastic detection?
Some compounds do not fluoresce naturally, and interactions between aromatic residues can make the spectrum difficult to interpret.
What is fluorescence?
A type of photoluminescence where a molecule absorbs light at one wavelength and emits it at a longer wavelength.
Component role
Tannic acid
Phenolic ligand forming the metal-phenolic network (MPN)
Component role
Zr⁴⁺
Metal ion cross-linking with tannic acid to create metal phenolic network.
Component role
Rhodamine B
Fluorophore providing luminescence for detection
Rhodamine B acts as the fluorophore in the L-MPN system, providing the luminescent signal for detecting nanoplastics via smartphone-based fluorescence microscopy. It is integrated into the metal-phenolic network coating that binds to nanoplastics, enabling rapid and selective visualization under LED excitation.
