Silicon Nitride Nanopores Formed by Simple Chemical Etching: DNA Translocations and TEM Imaging.

We demonstrate DNA translocations through silicon nitride pores formed by simple chemical etching on glass substrates using microscopic amounts of hydrofluoric acid. DNA translocations and transmission electron microscopy (TEM) prove the fabrication of nanopores and allow their characterization. From ionic measurements on 318 chips, we report the effective pore diameters ranging from zero (pristine membranes) and sub-nm to over 100 nm, within 50 µm diameter membranes. The combination of ionic conductance, DNA current blockades, TEM imaging, and electron energy loss spectroscopy (EELS) provides comprehensive information about the pore area and number, from single to few pores, and pore structure. We also show the formation of thinned membrane regions as precursors of pores. The average pore density, about 5 × 10-4 pores/µm2, allows pore number adjustment statistically (0, 1, or more). This simple and affordable chemical method for making solid-state nanopores accelerates their adoption for DNA sensing and characterization applications.

Squamous cell carcinoma at herniorrhaphy and unilateral renal agenesis.

Unilateral renal agenesis occurs infrequently. However, it has been associated with malignancies at multiple primary sites, anomalies of the genitourinary system, and supernumerary limbs. We present the case of a 60-year-old man with an incarcerated left inguinal hernia and renal insufficiency. At herniorrhaphy, he had squamous cell carcinoma in the hernia sac. A postoperative evaluation revealed unilateral renal agenesis, stage IV squamous cell carcinoma of the urinary bladder, and urolithiasis. The clinician should consider the genitourinary system as a primary site when patients present with the unusual finding of squamous cell carcinoma in the abdominal cavity and unilateral renal agenesis.