Nanosensors PDF

# NANOSENSORS ## OUTLINE - INTRODUCTION - NANOSENSOR TECHNOLOGY - TYPES - APPLICATIONS - FUTURE CHALLENGES ## INTRODUCTION ### WHAT IS NANO SENSOR? NANO + SENSOR - **SENSOR:** SENSES ACTION - **TRANSDUCER:** CONVERTS I/P TO ELECTRIC SIGNAL - **DETECTOR:** DETECTS CHANGE OCCURED ### DESCRIPTIO...

# NANOSENSORS ## OUTLINE - INTRODUCTION - NANOSENSOR TECHNOLOGY - TYPES - APPLICATIONS - FUTURE CHALLENGES ## INTRODUCTION ### WHAT IS NANO SENSOR? NANO + SENSOR - **SENSOR:** SENSES ACTION - **TRANSDUCER:** CONVERTS I/P TO ELECTRIC SIGNAL - **DETECTOR:** DETECTS CHANGE OCCURED ### DESCRIPTION - Sensors operating on the scale of atoms and molecules. - Smaller size, lower weight, modest power requirements. - Data storage systems. ## NANOSENSOR TECHNOLOGY - PHYSICAL SENSORS - CHEMICAL SENSORS - BIOSENSORS - Bio receptors - Transducers - Detectors ## TYPES - CANTILEVER ARRAY SENSORS - NANOTUBE SENSORS - NANOWIRE SENSORS ## TYPE: CANTILEVER ARRAY SENSOR - **WORKING:** BIO CHEMICAL/PHYSICAL PROCESS -> MICRO ELECTRO MECHANICAL SYSTEM ### FEATURES - PRECISSION CANTILEVERS: 300nm THICKNESS TOLERANCE - PRECISSION RESONANCE FREQUENCY: SPECIAL CANTILEVER MOUNT - EASY HANDLING: VERTICAL CHIP SIDEWALLS, OPTIONAL NON STICKING - CONTAMINATION FREE STORAGE ### SPECIFICATIONS - **SIZE/SHAPE:** RECTANGULAR SHAPED SILICON BARS. The silicon bar is 2.5mm wide and 3mm high. - **DUOSENSIS SENSORS:** 2 CANTILEVERS PER CHIP - **OCTOSENSIS SENSORS:** 8 CANTILEVERS PER CHIP ## APPLICATIONS - **FOR DIAGNOSIS OF DIABETES MELLITUS:** Small amounts of acetone in a patient's breath can be detected by cantilever array sensor technique which may attribute to early diagnosis of diabetes mellitus. - **FOR DETECTION OF BACTERIAS, FUNGI, VIRUSES:** Antigens on cell membrane surface results in additional mass loading, ultrasensitively detected by the device using nanochemical oscillator. The detection sensitivity is in the order of a single bacterium corresponding to a mass of ~1pg. - **FOR CANCER DIAGNOSIS:** When the cancer-associated molecules bind to the cantilevers, changes in surface tension cause the cantilever to bend. The mass detection limitation of NEMS cantilevers is improved to the enumeration of a single DNA molecule consisting of ~1600 base pairs and weighing ~1ag (atto = 10^18). ## TYPE: NANOTUBE SENSOR - **SIZE/SHAPE:** Coated with strands of DNA. Could detect molecules on the order of one part per million. ### PLATFORM - The Nano sensor could sniff molecules out of the air or taste them in a liquid, suggesting applications ranging from domestic security to medical detectors. ## APPLICATIONS - **FOR BLOOD GLUCOSE MONITARING:** Enzyme glucose oxidase is non-covalently attached. Brings catalysis of glucose yielding hydrogen-peroxide. Enzyme immobilisation allows flow of current. ## TYPE: NANOWIRE SENSOR ### STRUCTURE - SINGLE STRANDED DNA + CARBON NANOTUBE = NANOWIRE - DNA(DETECTOR) - NANOTUBE(TRANSMITTER) ## APPLICATION - **DETECTION OF SINGLE VIRUS:** Nanowires configured as a FET. Detection of single virus on receptors changes conductance. Nanosized wire required for high signal to noise ratio. - **DETECTION OF BIOMOLECULE:** Different molecules/viruses flow through the channel. Selective binding of protein/virus to appropriate nanowire. Information relayed through electrodes to computer. ### SILICON NANOWIRE - Used for detection of protein kinase viz cause of chronic leukemia. - Silicon Nano sensor with peptide nucleic acid distinguishes between these molecules. ## FUTURE CHALLENGES - TO IMPROVE SENSITIVITY OF CANTILEVER Nano sensor - UNWANTED BIOFOULING (DETECTION OF NON-ADSORBING MOLECULE) - USUAL DESIGN PROBLEMS - FLOW CONTROL - RISK AND ECONOMICS