Table 2.

Smartphone-based optical biosensors compared with benchtop techniques.

Application	Biosensor Type	Evaluated in Real Samples?	Pat. Nº, Year, State	Improvements of Smart Sensor vs. Benchtop Techniques	Ref.
H2O2 , Glucose and Catechol biosensor	Enzymatic: GOX and tyrosinase over poly(aniline-co-anthranilic acid)	Yes. Food and pharmaceutical samples		Polymeric substrate material and image processing software provided a great correlation with benchtop techniques and higher LOD.	[44]
HIV and Hepatitis B biosensor	DNA/RNA-linked biosensor	Yes. Plasma samples	WO2014089700A1, 2013 Pending [45]	They were able to detect between 103 to 109 copies/mL over a 20 µL sample and differentiate patients with HIV from those with HBV on the mono-infection assay and multiplexed detection of both of them in a co-infection assay. The results were quite well-correlated compared to benchtop equipment measurements.	[46]
Hemoglobin and HIV biosensor	Immunosensor	Yes. Blood samples	WO2016025698A1, 2014 Pending [47]	It consists of a combined pure optical assay and an immunoassay at the same time, and in the same device, without a difficult procedure for handling samples and reagents. The results are in good agreement with their commercial equivalents supported by smartphone technologies.	[48]
E. coli and S. typhimurium biosensor	Immunosensor	No		For the first time, a device capable of detecting two genetically related bacteria within a single sample drop is reported, with a LOD of 10−2 CFU/mL, in a fairly short time (12 min), and with a good consistency in comparison with the results obtained in laboratory experiments.	[49]
Zika, Dengue, Chikungunya detector	DNA/RNA-linked biosensor	No. Tested in artificial blood, urine, and saliva samples	US20160025630A1, 2014 Pending [50]	Detection technique that involves quenching of unincorporated amplification signal reporters (QUASR). Distinctively to other reported LAMP detection modalities, QUASR offers very bright signals, reduces the detection of false-positive amplification, and offers the ability to multiplex two or more targets per reaction. These features can highly reduce reagent costs and dilution needs when sample volume is limiting. A personalized smartphone application (app) controls the isothermal heating module and a LED excitation module via Bluetooth. The app processes images through a novel detection algorithm for multiplexed QUASR assay signals with greater accuracy than conventional image analysis software.	[51]
HIV1-p17, hemagglutinin (HA), and dengue virus type I detector	Bioluminiscent reporter	Yes. Blood plasma samples	WO2019038375A1, 2018 Pending [52]	The design shows to be an attractive analytical platform for point-of-care antibody detection that dispenses with liquid handling steps that are related to the major issues in immunoassays.	[53]
Inflammation and cell viability biosensors	Bioluminiscent reporters	No. Simulated proinflammatory and toxic samples.	US20120045835A1, 2009 Pending [54]	A limit of detection for tumor necrosis factor (TNFα) of 0.15 ± 0.05 ng/mL was achieved. This proposal promises to be a useful platform to preliminary screen environmental samples or other types of compounds for on-site detection.	[55]
Hemoglobin sensor	Label-free detection	No. Simulated samples.	US8861086B2, 2014 [56]	It stands out for its compact size, portability, low cost, the efficiency of optical spectroscopy for quantitative measurement, and ease of data collection, management, and computation.	[57]
			US20160296118A1, 2015 Pending [58]
Bovine immunoglobulinG (IgG)	Immunosensor	No. Spiked buffer solution of IgG protein	US20190025330A1, 2917 Pending [59]	In addition to the ability to detect immunoglobulins G, the device can be applied to the sensing of other analytes by properly functionalizing the gold film. The results and sensitivity obtained were comparable to commercial SPR instruments, so being a portable SPR system, it makes it an extremely useful device.	[60]
Chloride, sodium, and zinc in sweat	Fluorescence	Yes. Sweat	US20210145352A1, 2018 Pending [61]	Through an ultrathin, skin-compatible adhesive layer, the device allows sweat to be collected and distributed to different areas with fluorescent reagents. The device makes it possible to quantitatively determine, in a simple and low-cost device, several biomarkers of sweat at the same time.	[62]
Prostatespecific antigen (PSA)	Fluorescence	No. Spiked solution with PSA	US20120141746A1, 2009 Pending [63]	The device allows, through simple steps, to quantify different concentrations of PSA by means of fluorescence measurement with a smartphone. This sends the data to the cloud for processing and gives a result in about 1 min. It is not a practical device since it needs an objective lens (magnification 40×) to be able to capture the images with the smartphone.	[64]
			JP2008128677A, 2006 Pending [65]
			WO2017141503A1, 2016 Pending [66]