MUMBAI, India, Sept. 14 -- Intellectual Property India has published a patent application (202641100104 A) filed by Saveetha Institute Of Medical And Technical Sciences on August 19, 2026, for Lattice Resolved Crystalline Carbon Quantum Dots (cqds) From Cellulosic Biomass For Biosensing.
Inventors include Indra Neel Pulidindi; Muthupandi S; Mohammad Suhail Meer; Abhinaya M S; and Deepak Nallaswamy Veeraiyan.
The application for the patent was published on September 11, 2026, under issue no. 37/2026.
Abstract: Abstract Vile invention is about the single step conversion of the highly recalcitrant and sustainable material, namely, cotton (adsorbent cotton wool with over 98 wt. % cellulose) to carbon quantum dots (CQDs). The method of production of highly crystalline, luminescent, hydrophilic, oxygen surface functionalized CQDs comprises of subjecting cotton to hydrothermal reaction with 0.5 M NaOH as catalyst at a temperature of 200 °C for a short duration of 2 h. Typical process of synthesis of CQDs from cotton comprises of taking 0.5 g of cotton in a Teflon lined stainless steel autoclave and adding 50 mL, 0.5 M NaOH and subjecting the cotton in alkaline medium to hydrothermal process by sealing the reactor and placing the same in a convective air oven at 200 C for 2 h. Without any need for additional pretreatment of the feedstock, namely, cotton, CQDs are produced from cotton. The conversion of cotton was found to be 35 wt.% selectively to CQDs under the modest reaction conditions. The CQDs were separated from the unreacted cotton by filtration through Whatman filter paper as cotton is insoluble in water while the CQDs are highly solubilized and homogeneously dispersed throughout in the aqueous medium. The CQDs thus isolated were systematically examined for the optical, surface functional and structural properties using UV-Vis, Photoluminescence (PL) and FT-IR spectroscopies as well as the HR TEM analysis. The CQDs exhibited three characteristic bands at 269, 293 and 369 nm which could be attributed to the 7E-Ylt*, n—nr* transitions as well as the formation of singlet oxygen upon exposure to the UV -Vis irradiation respectively. Moreover, PL analysis revealed that the CQDs are highly fluorescent with down-conversion fluorescence. The CQDs exhibited excitation wave length dependent emission with a high Stokes shift value proving their potential for application in optical displays, LEDS, photocatalysis as well as for biosensing and bioimaging applications. FT -IR analysis showed C=C and C-C bonds in the highly conjugated cyclic structure indicative of the aromatic core. In addition, oxygen enriched surface functional groups, namely, C-O-C, C-0, Carboxylate, and hydroxyl groups were observed. HR TEM analysis revealed highly crystalline structure of the CQDs with an inter-planar spacing value of 0.2995 as deduced from the fast Fourier transform analysis. The CQDs are ultra-small with size less than 10 nm and were homogeneously distributed throughout the aqueous medium. The CQDs showed application for the ppb level biosensing of Cu II species in aqueous medium
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