Biology subjects

Athalye, S.

Publications and source records attributed to Athalye, S..

2 recordsLinked to original sources

bioRxiv2025

Limit of detection of Raman spectroscopy using polystyrene particles from 25 to 1000 nm in aqueous suspensions

Raman spectroscopy is an analytical method capable of detecting various microorganisms and small particles. Here, we used 25-1000 nm polystyrene particles in aqueous suspensions, which are comparable in size to viral particles and viral aggregates, to determine the limit of detection of a confocal Raman microscope. We collected Raman spectra using a 785 nm wavelength laser with a power of 300 mW and a 10 s exposure time, with a 5X objective lens. We detected the most prominent peak of the polystyrene particles at 1001 cm-1, corresponding to the ring breathing mode. We established the minimum and maximum limit of detection (LODmin and LODmax) using a partial least squares (PLS) model. The LOD of the smallest size of 50 nm was identified as 7.47 x 1012 -7.64 x 1012 particle/mL, and for the largest size of 1000 nm, 6.09 x 108 -6.24 x 108 particle/mL. We demonstrated that Raman spectroscopy was non-destructive under these conditions by comparing the particle size before and after collecting Raman spectra using dynamic light scattering. Due to their size similarity to viral particles and viral aggregates, this systematic characterization of polystyrene particles provides detailed information on their Raman spectral signatures in aqueous suspensions. These findings establish a foundation for using Raman spectroscopy for the detection of small particles in aqueous suspensions and highlight its potential as a tool for real-time monitoring in vaccine manufacturing.

bioengineering↗

bioRxiv2022

Increasing Muscle Hypertrophy with a Natural Product Designed to Inhibit SIRT1

Muscle mass and strength are predictors of longevity. We have previously identified a series of molecular brakes that slow muscle growth in response to stress. One potential stress that we hypothesized would limit muscle growth is caloric stress through the activation of SIRT1. We therefore identified natural product inhibitors of SIRT1 and tested their effects on load-induced increases in muscle fiber cross-sectional area (fCSA) using an incomplete factorial design. Supplying varying amounts of three natural products for the full two-week period of overload resulted in increases in fCSA that varied from -2 to 113%. Using these data, we produced a model that predicted the optimal combination and concentration of each natural product and validated this model in a separate cohort of animals. Following two weeks of overload, fCSA in the optimal group increased 62%, whereas in the placebo fCSA increased only 3%. The greater increase in fCSA was not the result of an increase in ribosomal mass. In fact, the optimal group showed significantly less of the 5 external transcribed spacer, a marker of 47S ribosomal RNA synthesis, and a trend for decreased total RNA. In spite of the lower ribosome mass, the increase in protein synthesis was similar, suggesting that the natural product cocktail may be increasing ribosomal efficiency rather than capacity. These data suggest that inhibition of SIRT1, together with exercise, may be useful in increasing muscle fCSA.

physiology↗