Cholesterol biosensor using Ph-responsive cnt nanobrush

1. Cholesterol biosensor using Ph-responsive cnt nanobrush Sudheesh K. Shukla1,2, Ajay Kumar Mishra1, Bhekie B. Mamba1, Ashutosh Tiwari1,2* 1UJ Nanomaterials Science Research Group, Department of Chemical Technology, Doornfontein Campus, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, Johannesburg, South Africa 2Biosensor and Bioelectronics, IFM-Linköpings universitet, 581 83 LINKÖPING, Sweden *Corresponding: ashutosh.tiwari@liu.se Purpose Thepointatattachment of sensing element upon sensors matrices • Induction of electrical charges • Highsensitive surface • High sensing element add-on Propertiesofsmart nanomaterial Ideal formofmatrices Reverse action used as scaffold for sensing elements • Small diameter • Similarity to the extracellular matrix of natural tissue • Large surface area • Increase in chance of adsorption of proteins/growth factors • Enhancement of rapid degradation • Small pore size • Permeanceofmaterials (e.g. nutrient or metabolite) Poly(styrene) ionic copolymers • High adhesion factors • Accelerationofdegradation • Improvementofionic deals • Verythinthickness • High bulk density in thedirection of the thickness Immobilization of sensing elemets into the matrices Polyaniline Ultra porous 2-dimensional surface Application of matrices for sensors (Formationofcontinuous surface in self-control process) Ontheotherhand… Electrochemical method method Functionalsmart features of materials-biomoleculesconjugates Theconstruction ofbiosensors Theaimofthisstudy Simple and efficient method to sense analytes Investigators have been designed new type of nanomatrices for ultra sensitive sensors. The significant improvements of sensor response, specificity and self life supported the up gradation of sensor design. Necessityofmatricesforbiosensors 1cm Electrochemical response Fabrication of ultra sensitive cholesterol biosensors Materials • Polyaniline(Aldrich, Inc., USA) • Carbon nanotube(CNT) (Aldrich, Inc., USA) • Cholesterol Esterase(ChEt (Aldrich, Inc, USA) • Solvent:H2O/H+ (NH2)2CO cholesterol esterase functionalized PANI-CNT/Pt nanocomposite Reaction of cholesterol over electrode surface a b Conclusion of study The biosensor showed a linear current response to the cholesterol concentration ranging from 30 to 280 mM. The influence of various parameters on cholesterol esterase enzyme activity within the PANI-CNT nanocomposite matrices was investigated including pH, temperature, and time. The Michaelis-Menten constant and apparent activities for the cholesterol esterase enzyme were calculated to be 0.84 mM and 108.03 mg/cm2, respectively; representing a very high affinity to functionalize cholesterol esterase enzyme onto PANI-CNT nanocomposite. 3D structure of CNT-PANI Nanobrush CV of (a) PANI-CNTnanocomposite and (b) cholesterol esterase functionalysed PANI-CNT nanocomposite Conclusion SEM of Cholesterol Esterase functionalized PANI-CNT nanocomposite SEM of PANI-CNT nanocomposite • The current efforts aim to use smart nanomaterials electrodes to formulate an efficient electrochemical sensors that can rapidly detect analytes from the biological samples viz. tears, urine, blood serum or directly from the blood. • The proposed sensor systems could broadly explore with a more nanoconfined structures like fiber, micelle, particle, brush, etc. for development of complex nanosensors to detect biomolecules in a less than nanomolar concentrations. • This new type of biosensor has demonstrated superior performance compared with those reported previously, including a higher sensitivity, wider range of detection limit in a nonomolar concentration range, and responded within few seconds. • Moreover, the proposed system may perhaps broadly explore with others vicinal diols of sugars for wide applications especially in medical and food checks. Acknowledgements: The authors thank Linköping University, Sweden and the European Commission (PIIF-GA-20​09-254955) for infrastructure facilities and generous financial support, respectively to carry out this research.