Biology subjects

Lao, K.

Publications and source records attributed to Lao, K..

3 recordsLinked to original sources

bioRxiv2025

Nano-Sieve Enabled On Chip Concentration and Multiplexed Detection of Raman-Dye Labeled Nanocubes

To address persistent challenges in molecular detection--particularly signal variability, low analyte abundance, and poor spectral reproducibility--a portable bead-stacked nano-sieve platform was engineered to enable robust on-chip Raman signal amplification using silver nanocubes (AgNCs) functionalized with Raman-active thiolated ligands. The microdevice integrates deformable elastomeric channels with magnetic bead stacking to immobilize and concentrate AgNCs within confined nanoscopic junctions, thereby generating densely packed plasmonic hot-spot architectures that markedly enhance Surface-Enhanced Raman Scattering (SERS) efficiency. Time-resolved measurements revealed substantial increases in Raman intensity for both 4-mercaptobenzoic acid (4-MBA) and 4-aminothiophenol (4-ATP), outperforming corresponding off-chip assays and maintaining stable enhancement factors over a four-hour operational window. Furthermore, the platform successfully demonstrated multiplexed sensing capability: mixed-analyte experiments containing 4-MBA, 4-ATP, and cysteamine produced clearly distinguishable spectral fingerprints, even under serial dilution and dynamically pulsed sample delivery. Collectively, these results establish the bead-stacked nano-sieve as a versatile, label-free, and scalable diagnostic architecture capable of achieving high sensitivity and spectral fidelity under continuous-flow conditions. Our technology holds significant promise for real-time, non-invasive molecular surveillance, point-of-care diagnostics, and early disease monitoring in resource-limited or field-deployable settings.

bioengineering↗

bioRxiv2024

A Draft Pacific Ancestry Pangenome Reference

Individuals of Pacific ancestry suffer some of the highest rates of health disparities yet remain vastly underrepresented in genomic research, including currently available linear and pangenome references. To begin addressing this, we developed the first Pacific ancestry pangenome reference using 23 individuals with diverse Pacific ancestry. We assembled 46 haploid genomes from these 23 individuals, resulting in highly accurate and contiguous genome assemblies with an average quality value of 55.0 and an average N50 of 40.7 Mb, marking the first de novo assembly of highly accurate Pacific ancestry genomes. We combined these assemblies to create a pangenome reference, which added 30.6 Mb of novel sequence missing from the Human Pangenome Reference Consortium (HPRC) reference. Mapping short reads to this pangenome reduced variant call errors and yielded more true-positive variants compared to the HPRC and T2T-CHM13 references. This Pacific ancestry pangenome reference serves as a resource to enhance genetic analyses for this underserved population.

genomics↗

bioRxiv2019

RNA Sequencing by Direct Tagmentation of RNA/DNA Hybrids

Transcriptome profiling by RNA sequencing (RNA-seq) has been widely used to characterize cellular status but it relies on second strand cDNA synthesis to generate initial material for library preparation. Here we use bacterial transposase Tn5, which has been increasingly used in various high-throughput DNA analyses, to construct RNA-seq libraries without second strand synthesis. We show that Tn5 transposome can randomly bind RNA/DNA heteroduplexes and add sequencing adapters onto RNA directly after reverse transcription. This method, Sequencing HEteRo RNA-DNA-hYbrid (SHERRY), is versatile and scalable. SHERRY accepts a wide range of starting materials, from bulk RNA to single cells. SHERRY offers a greatly simplified protocol, and produces results with higher reproducibility and GC uniformity compared with prevailing RNA-seq methods. Significance StatementRNA sequencing is widely used to measure gene expression in biomedical research; therefore, improvements in the simplicity and accuracy of the technology are desirable. All existing RNA sequencing methods rely on the conversion of RNA into double-stranded DNA through reverse transcription followed by second strand synthesis. The latter step requires additional enzymes and purification, and introduces sequence-dependent bias. Here, we show that Tn5 transposase, which randomly binds and cuts double-stranded DNA, can directly fragment and prime the RNA/DNA heteroduplexes generated by reverse transcription. The primed fragments are then subject to PCR amplification. This provides a new approach for simple and accurate RNA characterization and quantification.

molecular biology↗