Sensitive Blood-Based Detection of HIV-1 and Mycobacterium tuberculosis Peptides for Disease Diagnosis by Immuno-Affinity Liquid Chromatography-Tandem Mass Spectrometry: A Method Development and Proof-of-Concept Study.

BACKGROUND: Novel approaches that allow early diagnosis and treatment monitoring of both human immunodeficiency virus-1 (HIV-1) and tuberculosis disease (TB) are essential to improve patient outcomes. METHODS: We developed and validated an immuno-affinity liquid chromatography-tandem mass spectrometry (ILM) assay that simultaneously quantifies single peptides derived from HIV-1 p24 and Mycobacterium tuberculosis (Mtb) 10-kDa culture filtrate protein (CFP10) in trypsin-digested serum derived from cryopreserved serum archives of cohorts of adults and children with/without HIV and TB. RESULTS: ILM p24 and CFP10 results demonstrated good intra-laboratory precision and accuracy, with recovery values of 96.7% to 104.6% and 88.2% to 111.0%, total within-laboratory precision (CV) values of 5.68% to 13.25% and 10.36% to 14.92%, and good linearity (r2 > 0.99) from 1.0 to 256.0 pmol/L and 0.016 to 16.000 pmol/L, respectively. In cohorts of adults (n = 34) and children (n = 17) with HIV and/or TB, ILM detected p24 and CFP10 demonstrated 85.7% to 88.9% and 88.9% to 100.0% diagnostic sensitivity for HIV-1 and TB, with 100% specificity for both, and detected HIV-1 infection earlier than 3 commercial p24 antigen/antibody immunoassays. Finally, p24 and CFP10 values measured in longitudinal serum samples from children with HIV-1 and TB distinguished individuals who responded to TB treatment from those who failed to respond or were untreated, and who developed TB immune reconstitution inflammatory syndrome. CONCLUSIONS: Simultaneous ILM evaluation of p24 and CFP10 results may allow for early TB and HIV detection and provide valuable information on treatment response to facilitate integration of TB and HIV diagnosis and management.

Single-order, subwavelength resonant nanograting as a uniformly hot substrate for surface-enhanced Raman spectroscopy.

The surface-enhanced Raman spectroscopy (SERS) activity and the optical reflectance of a subwavelength gold nanograting fabricated entirely using top down technologies on silicon wafers are presented. The grating consists of 120 nm gold cladding on top of parallel silica nanowires constituting the grating's lines, with gaps between nanowires <10 nm wide at their narrowest point. The grating produces inordinately intense SERS and shows very strong polarization dependence. Reflectance measurements for the optimized grating indicate that (when p-polarization is used and at least one of the incident electric field components lies across the grating lines) the reflectance drops to <1% at resonance, indicating that essentially all of the radiant energy falling on the surface is coupled into the grating. The SERS intensity and the reflectance at resonance anticorrelate predicatively, suggesting that reflectance measurements can provide a nondestructive, wafer-level test of SERS efficacy. The SERS performance of the gratings is very uniform and reproducible. Extensive measurements on samples cut from both the same wafer and from different wafers, produce a SERS intensity distribution function that is similar to that obtained for ordinary Raman measurements carried out at multiple locations on a polished (100) silicon wafer.

Chemical corrosion protection of optical components using atomic layer deposition.

Very thin films deposited using atomic layer deposition (ALD) on aluminum mirrors showed extraordinary resistance toward concentrated alkali solutions, various chemical etchants, and solvents. Aluminum mirrors with no surface protection dissolved immediately in 24% aqueous KOH. Mirrors protected with 30 nm electron-beam deposited silica film were fully removed in 30 min. Mirrors with 10, 30, and 120 nm films grown by ALD required, respectively, 10, 15, and 60 h of exposure to the alkali for the mirror to be fully removed. Likewise, large-scale hydrogen bubbling was observed immediately upon immersing mirrors coated with electron-beam deposited silica in aqueous KOH, whereas no visible hydrogen bubbling was detected for the mirror protected by ALD silica. For mirrors protected by 120 nm ALD silica, a 2 h soak in various acid and solvent media produced no discernible change.