Resonant glassy nanostrings have been employed for the detection of biomolecules.

Resonant glassy nanostrings have been employed for the detection of biomolecules. which enabled the bio-functionalization of such products. Large arrays of nanostrings with ultra-narrow widths down to 10 nm were fabricated utilizing electron beam lithography. Diazonium changes was first developed on SiCN surfaces and validated by X-ray photoelectron spectroscopy. Similarly revised nanostrings were then covalently functionalized with anti-rabbit IgG like a molecular probe. Specific enumeration of rabbit IgG was successfully performed through observation of downshifts of resonant frequencies. 2-HG (sodium salt) The specificity of this enumeration was confirmed through proper bad control experiments. Helium ion microscopy further verified the successful functionalization of nanostrings. [38 39 Surface functionalization through electrochemical bonding gives strong adhesion and durability compared to fragile and fragile physical adsorption [40 41 However these chemical processes usually require complex apparatus and are restricted to particular types of surface. For example electrochemical surface changes requires special tools and is only relevant to conductive and semiconductor materials. Additionally the process often involves harsh chemicals and processes that deteriorate the material surface or denature the biological compatibility of the sensor system [40 41 Hence a simple milder versatile and 2-HG (sodium salt) biocompatible linker chemistry is needed. Diazonium salt reduction-induced aryl film grafting 2-HG (sodium salt) process matches such requirements [40 41 42 This one-step diazonium salt redox process is readily implemented in aqueous environments at room temp and ambient pressure and does not require sophisticated products. The relatively slight nature of the chemical process preserves the nature of both the modified material and the grafted thin film. Significant study involving diazonium-induced surface changes of biosensors has been conducted in recent years. Most of these reports were however limited to electrochemical detectors and surfaces such as carbon and metals [39 42 43 44 45 46 47 48 49 the best of our knowledge diazonium salt linker chemistry offers neither been applied to glassy sensor surfaces nor exploited to functionalize nanostrings of the type described 2-HG (sodium salt) here. The use of diazonium salt changes as linker chemistry for the bio-functionalization of glassy nanostring resonators is definitely reported here. First SiCN nanostring arrays were fabricated with string widths ranging from 300 nm down to 10 nm using electron beam lithography (EBL). The use of a glassy material is amenable to release through anisotropic etching of the underlying silicon. Such a feature allows strings as thin as 8 nm as long as tens of microns devoid of any undercut and dried without the need of a critical point drying step [27 50 51 In addition SiCN gives tunability of its tensile stress through a controlled post-deposition anneal [52]. Such a feature is definitely not available in additional glasses such as SiO2 and Si3N4. Diazonium-salt induced aryl film changes was then developed on these SiCN surfaces and analyzed by X-ray photoelectron spectroscopy (XPS). The process was then used to functionalize SiCN nanostring resonators. Anti-rabbit IgG proteins were covalently immobilized onto their surfaces using a common bio-conjugation technique. A obstructing coating was then added to inhibit non-specific binding. The nanostrings were then exposed to solutions comprising the prospective analyte EBL system (Raith Nanofabrication Dortmund Germant). Hydrogen silsesquioxane (HSQ XR-1541) was selected as an EBL resist for Eptifibatide Acetate its high resolution and simplified process sequence. Diluted 1% HSQ was spun coated onto the SiCN-coated wafer at a spin rate of 4000 rpm for 40 s and then baked at 90 °C for 5 min. The thickness of the HSQ coating was measured to be 28 nm using the Filmetrics system. The sample was revealed in the Raith tool using an electron beam voltage of 10 kV and a 10 μm aperture. For resonator anchoring pads and strings wider than 50 nm area doses of 0.5-1.75 mC/cm2 were used; whereas for strings narrower than 50 nm collection doses of 4.9-9.1 nC/cm were used. After exposure the HSQ was developed at room temp in 25% tetramethylammonium hydroxide (TMAH) for 75 s followed by a water rinse and.