arXiv subjects

Yingtao Yu

Publications and source records attributed to Yingtao Yu.

4 recordsLinked to original sources

arXiv2026

Nanoscale silicon sensor - guided new insights into early metabolic response of Escherichia coli to ampicillin

Antibiotic killing is often attributed to inhibition of specific cellular targets, yet metabolic processes can strongly influence drug efficacy. However, the relationship between metabolic responses and antibiotic lethality remains incompletely understood. Here, we employed silicon nanowire field-effect transistor (SiNWFET) sensors to monitor real-time metabolic responses of Escherichia coli to ampicillin (AMP). AMP treatment induced a biphasic extracellular pH signature, characterized by rapid acidification followed by alkalization. Metabolomic analyses revealed that the initial acidification resulted from organic acid secretion, whereas the subsequent alkalization was associated with altered amino acid metabolism and formate flux. Using metabolic and respiratory mutants, we found that these extracellular signatures reflected pathway-specific metabolic rewiring that predicted bacterial killing. AMP lethality strongly correlated with ATP dynamics and formate secretion: strains exhibiting larger AMP-induced ATP increases and greater formate secretion showed enhanced susceptibility. In contrast to literature, changes in NADH and NADPH levels did not support redox stress as the primary bacterial-killing mechanism. Together, our findings identify formate metabolism as a key pathway underlying the elevated ATP levels associated with AMP bactericidal activity. These results demonstrate that SiNWFET sensors provide a versatile label-free tool for probing antibiotic mechanisms, rapidly assessing bacterial susceptibility, and potentially guiding antimicrobial therapy development.

physics.ins-det↗

arXiv2025

A lab-on-a-silicon-chip platform for all-electrical antibiotic susceptibility tests with a sample-to-results time within 20 minutes

Rapid antibiotic susceptibility tests (ASTs) are essential for quick selection of effective drugs to treat bacterial infections at an early stage. However, the most widely used phenotypic ASTs in clinical practice often require 24 - 48 hours of pre-culture enrichment and 4 - 20 hours of testing. They are too slow to guide therapy, even with the most rapid protocol. Here, we report a lab-on-a-silicon chip (LOSC) system, which integrates arrays of silicon nanowire field-effect transistor (SiNWFET) sensors with high-throughput cell-collection microfluidics for rapid ASTs. The microfluidics concentrate bacteria into picoliter-scale chambers within minutes, eliminating the need for pre-cultivation. Embedded SiNWFETs sensitively track antibiotic-induced metabolic pH shifts, enabling AST by detecting rapid metabolic inhibition in susceptible bacteria. Using an unbuffered culturing medium, LOSC achieves sample-to-result times within 20 minutes for clinically isolated E. coli strains. With its electrical readout and compact design, LOSC offers a low-cost, rapid, and portable AST solution for point-of-care diagnostics.

physics.ins-det↗

arXiv2022

Minimal Steklov eigenvalues on combinatorial graphs

In this paper, we study extremal problems of Steklov eigenvalues on combinatorial graphs by extending Friedman's theory [Duke Math. J. 69 (1993), no. 3, 487--525] of nodal domains for Laplacian eigenfunctions to Steklov eigenfunctions, and solve an extremal problem for Steklov eigenvalues on combinatorial graphs that is an analogue of the extremal problem solved by Friedman [Duke Math. J. 83 (1996), no. 1, 1--18.] for Laplacian eigenvalues. More precisely, we mainly show that the minimum of the $i^{\rm th}$ Steklov eigenvalue on a connected combinatorial graph with $n$ vertices is essentially attained by a star with each arm a minimal broom when $i\not|n$, and attained by a regular comb with each tooth a minimal broom when $i|n$.

math.DG↗

arXiv2021

Monotonicity of Steklov eigenvalues on graphs and applications

In this paper, we obtain monotonicity of Steklov eigenvalues on graphs which as a special case on trees extends the results of He-Hua [Calc. Var. Partial Differential Equations 61 (2022), no. 3, Paper No. 101, arXiv: 2103.07696] to higher Steklov eigenvalues and gives affirmative answers to two problems proposed in He-Hua [arXiv: 2103.07696]. As applications of the monotonicity of Steklov eigenvalues, we obtain some estimates for Steklov eigenvalues on trees generalizing the isodiametric estimate for the first positive Steklov eigenvalues on trees in He-Hua [arXiv:2011.11014].

math.DG↗