Color-based breast milk analyses using test strips
Color-based (colorimetric) breast milk analyses using test strips (paper-based assays) read with the smartphone camera to quantify the concentration in accordance with embodiments of the invention are disclosed. In one embodiment, a color-based strip for testing breast milk is provided, the strip including: a first portion including a protein reagent pad where exposing the protein reagent pad to breast milk results in a first reaction for measurement of total protein concentration in the breast milk, a second portion including a fat reagent pad where exposing the fat reagent pad to breast milk results in a second reaction for measurement of fat concentration in the breast milk, and a third portion that is or includes a lactose reagent pad where exposing the lactose reagent pad to breast milk results in a third reaction for measurement of lactose concentration in the breast milk.
1 . A color-based strip, comprising:
a protein reagent pad comprising sodium bicinchoninate and cupric sulfate, wherein the protein reagent pad is configured to undergo a first reaction comprising a green-to-purple color change when the protein reagent pad contacts a sample, wherein the green-to-purple color change is proportional to a protein concentration of the sample, and is configured to generate a linear protein calibration curve from standardized protein concentrations of about 1.0 g/dl to about 1.6 g/dl;
a fat reagent pad comprising a pink dye indicator, lipoprotein lipase, glycerol phosphate oxidase, horseradish peroxidase, and galactose kinase, wherein the fat reagent pad is configured to undergo a second reaction comprising an off white-to-pink color change when the fat reagent pad contacts the sample, wherein the off white-to-pink color change is proportional to a fat concentration of the sample, and is configured to generate a linear fat calibration curve from standardized fat concentrations of about 1.5 g/dl to about 5.0 g/dl; and
a lactose reagent pad comprising beta-galactosidase, peroxidase and galactose oxidase, wherein the lactose reagent pad is configured to undergo a third reaction comprising a light green to blue then yellow color change when the lactose reagent pad contacts the sample, wherein the light green to blue then yellow color change is proportional to a lactose concentration of the sample, and is configured to generate a linear lactose calibration curve from standardized lactose concentrations of about 7.0 g/dl to about 9.0 g/dl.
2 . The color-based strip of claim 1 , wherein the sample comprises milk.
3 . The color-based strip of claim 1 , wherein the sample comprises breast milk.
4 . A method for quantifying macronutrient content, comprising:
splitting an image of a protein reagent pad comprising sodium bicinchoninate and cupric sulfate that is located on a color-based strip into a first plurality of color channels, wherein the protein reagent pad has contacted a sample and has undergone a green-to-purple color change proportional to a protein concentration of the sample;
generating a first spectrum value from at least one first color channel from the first plurality of color channels; and
calculating a protein concentration value of the sample by comparing the first spectrum value to a linear protein calibration curve generated from protein concentration standards comprising concentrations of about 1.0 g/dl to about 1.6 g/dl protein;
splitting an image of a fat reagent pad comprising a pink dye indicator and one or more of lipoprotein lipase, glycerol phosphate oxidase, horseradish peroxidase, and galactose kinase that is located on the color-based strip into a second plurality of color channels, wherein the fat reagent pad has contacted the sample and has undergone an off white-to-pink color change proportional to a fat concentration of the sample;
generating a second spectrum value from at least one second color channel from the second plurality of color channels;
calculating a fat concentration value of the sample by comparing the second spectrum value to a linear fat calibration curve generated from fat concentration standards comprising concentrations of about 1.5 g/dl to about 5.0 g/dl fat;
splitting an image of a lactose reagent pad comprising one or more of beta-galactosidase, peroxidase and galactose oxidase that is located on the color-based strip into a third plurality of color channels, wherein the lactose reagent pad has contacted the sample and has undergone a light green to blue then yellow color change proportional to a lactose concentration of the sample;
generating a third spectrum value from at least one third color channel from the third plurality of color channels; and
calculating a lactose concentration value of the sample by comparing the third spectrum value to a linear lactose calibration curve generated from lactose concentration standards comprising concentrations of about 7.0 g/dl to about 9.0 g/dl lactose;
thereby calculating the macronutrient content of the sample.
5 . The method of claim 4 , wherein the at least one first color channel comprises a first red color channel, a first green color channel, or a first blue color channel.
6 . The method of claim 4 , wherein the at least one second color channel comprises a second red color channel.
7 . The method of claim 4 , wherein the sample comprises milk.
8 . The method of claim 4 , wherein the sample comprises breast milk.