The present invention provides compositions that can be used to modify charge transport across a nanocrystal surface or within a nanocrystal-containing matrix, as well as methods for making and using the novel compositions. A method for preparing a coated substrate employing the aqueous polymer dispersion is also provided. Each force-sensing unit includes a vertical sensor positioned fore and aft of the vertical hitch axis and forward and aft horizontal force sensors. Various alignment guides are useful with surgical instruments to obtain a reference plane.