The rare earth metal, ytterbium appears to be an emerging substance with respect to patent publications with a marked increase in relative growth increasing post 2008. In recent years, ytterbium appears to have been referred to in the context of fluorescent nanosensors and colorimetric nanosensors as NaYF4 upconversion nanoparticles in patent publications. Another example from the element subclass that appears to be an emerging substance with respect to patent publications is graphene, showing exceptional increase in patent publications post 2010 with a plateau between 2017-2020 and a subsequent slight decrease. An interesting example of patent mentioning graphene did so in the context of semiconductor biosensors incorporated into face masks capable of analyzing exhaled breath to potentially detect biomarkers for cancer and viral infections. Other examples include alcohol sensors and carbon monoxide sensors. The elements nitrogen, copper, chlorine, nickel and oxygen appear in the top 15 emerging substances with respect to journal publications (and not patents). Examples of these elements in the context of nanosensors appear to include both as materials used in the fabrication of nanosensors as well as substance detected using nanosensors. Examples of the former include nitrogenated holey graphene-based gas sensors used to detect flammable and toxic gases propane and butane, Cu/Al electrodes in strain sensors and NiCo2S4 nanosheets for sensing glucose and ascorbic acid. Examples of latter include zinc oxide nanotube-based NO2 gas sensors and N-doped molybdenum oxide quantum dots-based fluorescence sensor for detection of Cu 2+ . Among emerging polymers, synthetic polymers tend to outnumber natural polymers with cellulose and chitosan being the only natural polymers featured in the top 15 for both journal and patent publications (Figure ). Examples include journal publications describing the use of cellulose in electrochemical, flexible strain and chemosensors 60 often as nanofibers and in combination with other materials (including synthetic polymers) used for applications such as health monitoring, heavy metal detection and in the food industry amongst others. The use of chitosan has been explored in sensors across several biomedical applications including in wearable sensors for health monitoring including continuous monitoring of the neurotransmitter serotonin considered a biomarker for depression. Often chitosan is used in conjunction with other materials in the fabrication of these sensors including synthetic polymers such as polyaziridne as well as metals and metal oxides. Patent publications show similar use/applicability of cellulose and chitosan including metal organic framework (MOF)-multiwalled carbon nanotube (MWCNT)/chitosan composites for electrochemical detection of tryptophan enantiomers. Semiconducting polymers such as poly(dopamine) (PDA), PPy, polyaniline (PANI) and PEDOT; the fluoropolymer PTFE and poly(vinylidene fluoride) (PVDF); water soluble polymers such as poly(vinyl alcohol) (PVA), poly(vinylpyrrolidone) (PVP), polyethylene glycol (PEG) are some of the emerging synthetic polymers in the field of nanosensors based on our analysis. Other emerging synthetic polymers include poly(styrenesulfonic acid) and polyaziridine. PDA in particular exhibits a sharp growth in patent publications after 2012 (Figure ). A type of semiconducting polymer, PDA is composed of repeating units of dihydroxyindole, indoledione and dopamine and is synthesized by subjecting dopamine to oxidation. Often fabricated as nanoparticles, PDA is also frequently used as coating to modify surface properties of a wide variety of materials. In the context of nanosensors, PDA coated CNTs were embedded in a PVA-PEG hydrogel matrix to fabricate flexible wearable sensors. In another instance, PDA-gold nanoparticles were used to decorate stellate mesoporous silica in a bid to improve characteristics/properties such as stretchability, sensitivity, tensile strength, self-healing properties among others to enable design of PDA is also frequently used as coating to modify surface properties of a wide variety of materials. Use of PDA reported in patent applications appears to be similar to those reported in journal publications including use of PDA-multi-walled CNTs in electrochemical sensors. Another well-known semi-conducting polymer, PEDOT, shows consistent and increasing growth in journal and patent publications since 2008 (Figure ). The excellent conducting properties of PEDOT make it particularly well suited for use in nanosensors, examples of which include MXene/CNT/PEDOT composite-based respiratory sensor, sensors composed of wood sponge decorated with SWCNT/PEDOT:PSS capable of detecting pulse and temperature and MXene-PEDOT:PSS-PPy nanosheets used as wearable sensors for real-time monitoring of sweat in terms of sodium and creatinine levels. PANI has been utilized to detect small molecules such as formaldehyde in the form of PANI/Zn bismuthate nanocomposite decorated carbon electrodes; amoxicillin, a penicillin antibiotic, in water bodies as PANI-silver bromide composites ; as mesoporous silicon-PANI nanocomposite to detect levels of thiourea. Most often the small molecules detected are considered pollutants whose consumption adversely affects human beings. In addition, PANI-based sensors also find applicability in areas such as detection of pathogenic bacteria, monitoring humidity and colorimetric sensors for pH measurement. Many PANI-based sensors are electrochemical sensors that utilize the excellent conducting properties of PANI. The organic/inorganic small molecule subclass of substances show the least overlap between emerging substances associated with journal and patent publications (3,3',5,5'tetramethylbenzidine, thiourea, molybdenum disulfide and glycerol). Glycerol often appears in the context of a solvent used for synthesis of hydrogel sensors as well as components of hydrogels and in some instances as protectant against temperature induced changes. Similarly, thiourea is often mentioned as part of synthesis of nanomaterials. Another context in which thiourea often appears is in terms of development of nanosensors for its detection. Molybdenum disulfide (MoS2) nanoparticles appears to be often employed in a variety of different nanostructures including quantum dots, 100 nanoroses 101 /flower-like structures, 102, 103 and nanosheets 104 for environmental applications including monitoring water quality 101 and detection of volatile organic compounds 103 as well as biomedical applications such as detection of biomolecules 100, 105, 106 and health monitoring 107 to name a few. MoS2 is also often used as a modifier of CNTs 106, 108, 109 often to enhance their conductivity. The wide applicability of MoS2 can perhaps be attributed to its good electronic, optical, and chemical properties. The oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) resulting in a colored product is a well-known phenomenon with TMB which is exploited in colorimetric sensors along with a wide variety of other nano-based materials. Salts such as silver chloride (AgCl), sodium chloride (NaCl), iron chloride (FeCl3) and basic compounds such as triethylamine and potassium hydroxide (KOH) and the strong acid hydrochloric acid (HCl), are the other emerging small molecules more so in journal publications. Silver chloride (AgCl) is often used in reference electrodes and as components of nanocomposites. Nanosensors have been tested for their sensitivity in the presence of varying concentrations of sodium chloride (NaCl). Iron chloride (FeCl3) appears in the context of synthesis and may be utilized in the synthesis of both ferric oxide nanoparticles and Fe-MOF nanocomposites. Similarly, urea has also been used in the synthesis of nanocomposites. Triethylamine can be used as a solvent in the synthesis of nano-based materials. Nanosensors have also been developed to detect presence and levels of triethylamine considered an environmental pollutant. Dimethylformamide (DMF) 127, 128 is also often used as solvent in synthesis. Potassium hydroxide (KOH) has been used to achieve activation of porous carbon nanosheets (PCN) for use as Pt-Ni@PCN nanocomposites in sensors for detecting environmental pollutants. KOH has also been used in the synthesis of nanocomposites. Other small molecules associated with journal publications are toxic gases such as carbon dioxide and sulfur dioxide and isopropanol, 136-139 a volatile organic compound, detected using nanosensors.