Ultra-soft atomic force microscope (USAFM) technology using nano-cantilevers for

DESCRIPTION (provided by applicant): NaugaNeedles LLC in collaboration with researchers from Purdue University are proposing to develop an advanced new Ultra-Soft Atomic Force Microscope (USAFM). This USAFM can gently create images of soft biological samples in buffer solutions with sub-picoNewton (pN) forces and sub-nm lateral resolution. This new AFM technology will have a high-bandwidth to ensure compatibility with high speed scanners. The USAFM requires development of (1) a new, small mass, ultra-soft, yet high frequency cantilevers with sharp tips and (2) an advanced motion detector instrumentation to detect ultra-soft cantilever motions. The key is to significantly decrease the cantilever's mass, which will consequently increase its resonance frequency and decrease its thermal vibration at low frequencies. Metallic silver-gallium (Ag2Ga) nano- cantilevers produced by NaugaNeedles are Ideal candidates for ultra-sensitive cantilevers since (a) they are orders of magnitude smaller than conventional cantilevers, (b) have approximately two orders of magnitude softer (k~10-4 N/m) bending stiffness, and (c) have a resonance frequencies of approximately 1-2 orders of magnitude higher than the softest commercially available cantilevers. Since this new AFM technology will have a high-bandwidth it will be compatible with high speed scanners. To demonstrate the feasibility of the USAFM, Phase I has three specific aims: 1. Fabrication of ultra-soft probes (USPs): Silver-gallium (Ag2Ga) crystalline nano- cantilevers will be fabricated in various lengths (5 to 50 ltm) and widths (100 to 500 nm). A sharp molecular tip (e.g. Fibrinogen fiber) will be grown on each nano-cantilever to provide a small tip radius (5-10 nm), converting the bare nano-cantilever into high-resolution ultra-soft- probes (USPs) for USAFM. 2. Optical detection of nano-cantilever deflection: Nano-cantilevers with different length-to- diameter ratios fabricated under aim 1 will be tested to optimize the optical detection of their motion, using an existing scanning micro-Laser Doppler Vibrometer (LDV). Thermal vibration spectra of the nano-cantilevers in air and under water will be measured using the micro-LDV to estimate the force measurement limits of the proposed USAFM. 3. Experimental calibration and imaging under liquids: USPs fabricated on commercially- available AFM cantilevers will be tested in a conventional AFM to establish force calibration protocols and compatibility for scanning under liquids. In Phase II, a prototype of USAFM head will be built and tested for high resolution imaging and studying the electromechanical properties of biological systems under liquids. Also a batch fabrication process will be developed to mass produce USPs, at a low cost. In Phase III, NaugaNeedles will partner with Nanotec Electronica and Agilent (the manufacturer of the AFM controller) and Polytec (the LDV manufacturer) to commercialize the USAFM. The annual market size for the USAFM and USPs (that are consumable products) is expected to exceed 50 million by 2012, with no competition in sight. PUBLIC HEALTH RELEVANCE: The focus of this proposal is to develop an ultra-soft atomic force microscope (USAFM). The USAFM can gently create images of soft biological samples with molecular resolution in liquid environments. This is done by applying sub-picoNewton (pN) forces to the molecules. To successfully develop a USAFM NaugaNeedles should first develop (1) a new, small mass, ultra-soft, yet high frequency cantilevers with sharp tips and (2) an advanced motion detector instrumentation to detect ultra-soft cantilever motions. This new and enhanced AFM technology will have a high-bandwidth, ensuring its compatibility with high speed scanners.