Luminescent Diamond Particles for Stable Biological Imaging
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Solution Overview
Problem
Current biological imaging techniques face challenges due to high fluorescence background signals from endogenous biomolecules and the detrimental photophysical properties of existing fluorescent probes, such as photobleaching and toxicity, which limit their application for long-term observations.
Innovation Solution
Development of luminescent diamond particles (LDPs) with high photobleaching thresholds, broad excitation, and narrow emission spectra, which are chemically inert, biocompatible, and can be easily functionalized for specific or nonspecific binding, allowing for bright fluorescence without photobleaching or blinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If organic dyes or fluorescent proteins are used to avoid endogenous fluorescence interference, then fluorescence emission wavelength is shifted to longer wavelengths (>600 nm), but photobleaching and blinking occur which restrict long-term observations
Solution Approach 1:
The patent changes the material parameter from organic dyes/proteins to inorganic diamond particles, which fundamentally alters the photophysical properties. Diamond particles exhibit exceptional photostability with no photobleaching or blinking, while maintaining tunable fluorescence emission in the red-to-near-infrared region through control of color center concentration and type.
Solution Approach 2:
The patent creates composite fluorescent probes by combining diamond particles with functional coatings or conjugating them to biomolecules. This composite structure provides both the photostability of diamond and the biological functionality needed for targeting and imaging applications.
2Reliability
If fluorescent semiconductor nanocrystals are used to achieve high photobleaching thresholds and multicolor labeling, then photostability is improved, but cytotoxicity and human toxicity increase
Solution Approach 1:
The patent replaces toxic semiconductor nanocrystals with biocompatible diamond particles that can be safely used in biological systems. Diamond is chemically inert and non-toxic, eliminating the need for complex surface modifications while maintaining photostability.
Solution Approach 2:
The patent uses diamond's inherently inert chemical environment to avoid toxicity. Diamond particles do not require reactive surface coatings to achieve biocompatibility, unlike semiconductor nanocrystals which need protective shells to reduce cytotoxicity.
3Object-affected harmful factors
If surface modification is applied to semiconductor nanocrystals to reduce toxicity, then cytotoxicity is reduced, but photophysical properties are altered which limits biological application scope
Solution Approach 1:
The patent uses diamond particles that are inherently biocompatible and photostable without requiring surface modifications. The material's intrinsic properties provide both safety and performance, eliminating the trade-off between toxicity reduction and property preservation.
4Quantity of substance
If endogenous biomolecules are present in biological systems, then natural fluorescence background signals are generated, but this interferes with detection of fluorescent probes
Solution Approach 1:
The patent exploits the difference in emission wavelengths between endogenous fluorophores (typically 400-550 nm) and diamond particle fluorescence (tunable red-to-near-infrared). By selecting diamond particles with emission wavelengths >600 nm, the probe signal falls in a spectral region with minimal endogenous interference, greatly improving signal-to-background ratio.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
LDPs provide stable, low-cytotoxicity fluorescence suitable for biological applications like biomolecular labeling, cellular imaging, and drug delivery, with no signs of photobleaching or blinking under high-power laser excitation, enabling long-term observations and multicolor-emission capabilities.
Implementation Method 1
diamond particles with a diameter of 1 nm to 1 mm are first irradiated by an ion beam having a kinetic energy of 1 KeV to 900 MeV
Implementation Method 2
then heated in a non-oxidizing atmosphere at 600 to 1000° C
Implementation Method 3
capable of fluorescing from point defects
Data Source
AI summary
A method for preparing luminescent diamond particles (e.g., fluorescent nanodiamonds). The method includes irradiating diamond particles with an ion beam and heating the irradiated diamond particles in a non-oxidizing atmosphere at a temperature between 600 and 1000° C. The diamond particles have a diameter of 1 nm to 1 mm and the ion beam has a kinetic energy of 1 KeV to 900 MeV. Also disclosed are luminescent diamond particles prepared by this method and methods of using them.