505nm Bandpass Filter

Context: This patent details a method for evaluating the effectiveness of antiperspirant and deodorant products by measuring bacterial populations on skin (specifically the axilla/underarm area). The method relies on fluorescence measurements rather than traditional manual counting.

Usage of Filter: A 505 nm bandpass filter is placed in front of the photomultiplier (detector) in the fluorescence measurement apparatus.

Function: It filters the light coming from the skin sample, which has been illuminated with a Xenon arc lamp (filtered to 290-400 nm excitation). The 505 nm filter isolates the specific fluorescence emission wavelength associated with the bacterial porphyrins or tryptophan-like signals.

Result: It allows for the precise quantification of bacterial fluorescence intensity while blocking the excitation light and other background noise. This intensity correlates directly to bacterial counts, providing a rapid, non-invasive way to determine if a deodorant successfully reduced bacterial presence.

Context: This patent focuses on the creation and use of novel Green Fluorescent Protein (GFP) variants derived from Aequorea victoria. These proteins are used as biological markers to visualize gene expression and protein localization in living cells.

Usage of Filter: The patent describes using an emission bandpass filter, specifically mentioning ranges like 505-530 nm or 505-555 nm (often with a 505 nm cut-on or center), in fluorescence microscopy setups.

Function: The filter is tuned to match the peak emission of the GFP variants (which typically fluoresce strongly around 509 nm). It discriminates this signal from the excitation light (usually 488 nm blue light) and autofluorescence from the cell.

Result: It produces high-contrast images where only the specific proteins tagged with GFP are visible against a dark background. This enables researchers to track dynamic biological processes inside a cell with high spatial resolution.

Context: This patent describes an advanced optical system for detecting fluorescence in samples moving through a flow cell or capillary, commonly used in DNA sequencing and flow cytometry. The goal is to maximize light collection while minimizing background noise (scatter).

Usage of Filter: A 505 nm bandpass filter (specifically cited as a "505 nm band pass filter" in some embodiments) is positioned in the collection path of the optical assembly.

Function: It serves as a spectral discriminator. When a sample labeled with a specific fluorophore (like Fluorescein) is excited by a laser, the filter passes only the narrow band of light centered at 505 nm (the peak emission for Fluorescein) to the detector.

Result: It significantly improves the signal-to-noise ratio by rejecting Raman scattering from the solvent and stray laser light. This allows the system to detect extremely small amounts of fluorescent material, which is critical for accurate DNA sequencing or identifying rare cell types.