"Burn after reading"-transient fluorescent hydrogel for information protection

In the era of highly developed information technology in the 21st century, our daily lives are flooded with massive amounts of data and information, and the channels of information dissemination are also very diversified
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However, while people feel the convenience of obtaining information, they are also suffering from the leakage of confidential information and false information
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Therefore, it is extremely important for the development of information encryption-decryption technology and corresponding anti-counterfeiting technology
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? Information encryption-decryption to protect confidential information and prevent its leakage mainly involves the encryption and decryption of information and the subsequent information destruction process (as shown in the figure below).
Each step is critical to the degree of information security
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Schematic diagram of information encryption-decryption-destroy The encryption-decryption technology can be traced back to the use of fire paint to seal the letter to maintain the security of the letter.
The integrity of the fire paint is used to determine whether the information is leaked
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In ancient Greece, people obtained information in a specific arrangement by wrapping cloth strips with information on wooden sticks of specific thickness at a certain angle and direction
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Of course, there are Morse ciphers that we are still using now, which mainly use the signal codes that are on and off at all times, and the Morse ciphers that represent different English letters or numbers through different arrangements
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In addition, the steganography that we often see in spy films is also an extremely commonly used encryption-decryption technique.
Spies use invisible ink such as lemon juice or rice soup to write.
When decrypting, they only need to roast or smear.
The information can be displayed in the form of iodine solution
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? With the continuous development of technology, a variety of new information encryption methods emerge in an endless stream, such as digital codes, holographic anti-counterfeiting, FRID technology, watermarking, fluorescent recognition and so on
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? The encryption-decryption process of the information burned after reading ensures the security of the information in the transmission process.
However, if the decrypted information is not properly processed, there is still the risk of secondary information leakage
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Therefore, there is an urgent need to develop new smart display modes and prepare novel information storage materials, especially advanced information storage devices that can destroy encrypted information in a timely manner after decryption, to improve information security
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? In fact, in real life there is no shortage of such apps/software and emails with the function of "burning after reading".
The most typical one is the photo sharing application called "Snapchat" developed by two students from Stanford University.
All photos have a life span of 1-10 seconds and can be automatically destroyed at a set time
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? Inspired by this, recently, the research group of Chen Tao researcher of Ningbo Institute of Materials Technology and Engineering of Chinese Academy of Sciences and the research group of Professor Liu Mingjie of Beihang University have reported a kind of intelligent hydrogel with transient fluorescence performance and used it in Multi-level information storage realizes the "burning after reading" of information (as shown in the figure below)
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? Figure The design of transient fluorescent hydrogel and its use for multi-level information encryption-decryption-self-erasing.
This work involves introducing urease in situ in the polyacrylamide hydrogel network, using urease-urea catalysis In the reaction, the naphthimide fluorophore is transformed from the protonated state (DEAN-H+) to the deprotonated state (DEAN) in situ, achieving the effect of rapidly reducing the fluorescence intensity of the hydrogel
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In addition, the naphthimide fluorophore can also cooperate with different metal ions (Zn2+, Al3+), while maintaining the fluorescence intensity of the hydrogel, while reducing the rate at which the fluorescence intensity of the hydrogel is weakened (in a urea solution) )
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Through the introduction of a metal ion, the huge difference in the time dimension between the deprotonation process and the decoordination process can be used to realize the display of information and "burn after reading" (as shown in the figure below)
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? The decryption and self-erasing process of the encrypted information is based on the above.
If the metal ions Zn2+ and Al3+ are introduced at different positions on the hydrogel surface at the same time by ion printing and dyeing technology, the binding ability of different metal ions and naphthalimide fluorophores is different.
In the decryption process through the urea solution treatment, the rate of fluorescence weakening is different, then the time and air conditioning control of the fluorescence intensity of the hydrogel surface can be realized, and the decryption of multi-level encrypted information-self-erasing multi-level information encryption-decryption-self Erase (as shown below)
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? Figure multi-level information decryption process example? Multi-level information decryption example 1: "9"-"5"-disappeared Multi-level information decryption example 2: "Sen"-"Lin"-disappeared multi-level information decryption example 3: Xingyue -Month-Disappearance Multi-level Information Decryption Example 4: Ursa Major-Big Dipper-Disappear