Another albumin assay kit was reported by Naghdi et al. In this study, they present a novel analytical device called the "lab-on-nanopaper" or NAD, which is based on a transparent bacterial cellulose (BC) nanopaper embedded with curcumin. The NAD allows for visual sensing of human serum albumin (HSA) in human blood serums, and is a promising platform for the development of optical biosensors due to its excellent properties such as optical transparency, high flexibility, porosity, biodegradability, and printability. To create the hydrophilic test zones, hydrophobic walls were printed onto the bioplatform using laser technology. The color changes of curcumin embedded in the BC nanopaper (CEBC) due to the inhibitory effect of HSA on the curcumin degradation in alkaline solutions, were linearly proportional to the HSA concentration in the range of 10-300 μM and 25-400 μM, respectively. The developed NAD/CEBC was successfully utilized as an albumin assay kit for the determination of HSA in human blood serum samples with satisfactory results. The NAD/CEBC is a promising optical sensing bioplatform that can be used as an efficient, portable, affordable and easy-to-use assay kit for HSA monitoring. Its color changes can be monitored visually (naked eye/Smartphone camera) or spectroscopically using a spectrophotometer. It is also an eco-friendly analytical tool since it utilizes safe, non-toxic and green materials like curcumin and nanopaper, and requires minimal sample volume for HSA detection.