pH-sensitive nanoparticles for detecting and preventing food spoilage
Nanoparticles and compositions thereof are provided for detecting and/or preventing food spoilage. Methods of making the nanoparticles and compositions, and methods of using the nanoparticles and compositions, e.g. in food packaging, are also provided. The nanoparticles can have a hydrophobic core containing a hydrophobic active agent, e.g. a hydrophobic dye and/or an antimicrobial agent, for detecting and/or preventing food spoilage. The nanoparticles can also have a copolymer of a hydrophobic polymer repeat unit, e.g. styrene or lactic acid, and a pH responsive dendrimer repeat unit. The pH responsive dendrimer repeat unit can have a pH responsive amine core having a plurality of branched acrylate arms extending therefrom. The nanoparticles can be chemically stable at neutral pH, and then release the hydrophobic active agent at a pH range indicative of food spoilage. By releasing the hydrophobic dye and/or antimicrobial agent, the nanoparticles can detect and/or inhibit food spoilage.
1. A nanoparticle for the detection of food spoilage, the nanoparticle comprising:
a hydrophobic core comprising a hydrophobic dye; and
a copolymer of a hydrophobic polymer repeat unit and a pH responsive dendrimer repeat unit,
wherein the pH responsive dendrimer repeat unit has a structure according to the following formula or a derivative thereof,
wherein each occurrence of X is independently a branched acrylate arm having a structure according to the following formula
wherein each occurrence of B is a substituted or unsubstituted, linear or branched alkyl, heteroalkyl, alkenyl, alkynyl, carbocyclic, or heterocyclic group,
wherein m is an integer of 2 to 8,
wherein the pH responsive dendrimer repeat unit is present at an amount from about 5 wt % to 20 wt % based upon the weight of the copolymer,
wherein the nanoparticle is chemically stable and has a diameter of about 50 nm to 200 nm at neutral pH, and
wherein the nanoparticle releases the hydrophobic dye at a pH range of about 4.5 to 6.7 to indicate the food spoilage.
2. The nanoparticle according to claim 1 , wherein the pH responsive dendrimer repeat unit has a structure according to the following formula
3. The nanoparticle according to claim 1 , wherein the pH responsive dendrimer repeat unit has a structure according to the following formula
4. The nanoparticle of claim 1 , wherein the nanoparticle has a diameter of 50 nm to 250 nm.
5. The nanoparticle of claim 1 , wherein the hydrophobic polymer repeat unit is selected from the group consisting of a fluorocarbon, a tetrafluoroethylene, a vinylfluoride, a siloxane, a dimethylsiloxane, butadiene, a methacrylate, ethylene, an olefin, styrene, propylene, and an oligomer thereof.
6. A packaged food product comprising:
a food product;
a packaging containing the food product; and
a composition comprising a plurality of the nanoparticles according to claim 1 .
7. The packaged food product according to claim 6 , wherein the pH responsive dendrimer repeat unit has a structure according to the following formula
8. The packaged food product according to claim 6 , wherein the pH responsive dendrimer repeat unit has a structure according to the following formula
9. The packaged food product of claim 6 , wherein the food product is selected from the group consisting of beef, pork, poultry, and fish.
10. The packaged food product of claim 6 , wherein the packaged food product is a ready-to-eat food product.
11. The packaged food product of claim 6 , wherein the composition is part of the packaging and is in contact with the food product inside the packaging; and
wherein a release of the hydrophobic active agent indicates the food has spoiled, inhibits or prevents the growth of a food spoilage microorganism, or both.