A uniformly oriented purple membrane (PM) monolayer containing photoactive bacteriorhodopsin has recently been applied as a sensitive photoelectric transducer to assay color proteins and microbes quantitatively. This study extends its application to detecting small molecules, using adenosine triphosphate (ATP) as an example. A reverse detection method is used, which employs AuNPs labeling and specific DNA strand displacement. A PM monolayer-coated electrode is first covalently conjugated with an ATP-specific nucleic acid aptamer and then hybridized with another gold nanoparticle-labeled nucleic acid strand with a sequence that is partially complementary to the ATP aptamer, in order to significantly minimize the photocurrent that is generated by the PM. The resulting ATP-sensing chip restores its photocurrent production in the presence of ATP, and the photocurrent recovers more effectively as the ATP concentration increases. Direct and single-step ATP detection is achieved in 15 min, with detection limits of 5 nM and a dynamic range of 5 nM-0.1 mM. The sensing chip exhibits high selectivity against other ATP analogs and is satisfactorily stable in storage. The ATP-sensing chip is used to assay bacterial populations and achieves a detection limit for and of 10 and 10 CFU/mL, respectively. The demonstration shows that a variety of small molecules can be simultaneously quantified using PM-based biosensors.
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http://dx.doi.org/10.3390/s23177453 | DOI Listing |
Sci Rep
December 2024
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
Hypomethylating agents (HMAs) such as azacytidine and decitabine are FDA-approved chemotherapy drugs for hematologic malignancy. By inhibiting DNA methyltransferases, HMAs reactivate tumor suppressor genes (TSGs) and endogenous double-stranded RNAs (dsRNAs) that limit tumor growth and trigger apoptosis via viral mimicry. Yet, HMAs show limited effects in many solid tumors despite the strong induction of TSGs and dsRNAs.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. Electronic address:
Lead ion (Pb) is a common environmental contaminant, extremely toxic, persistent, and easily adsorbed, concentrated, and enriched by agricultural products. Ingestion of this ion can result in health problems for humans, including neurological disorders, heart disease, brain damage, and mental deficiency. In this research, a sensitive fluorescent biosensing method for detecting Pb was developed using DNAzyme as the target recognition element and SYBR Green (SG) fluorescent dye as the signal indicator.
View Article and Find Full Text PDFBiosensors (Basel)
December 2024
CUHKSZ-Boyalife Regenerative Medicine Engineering Joint Laboratory, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China.
The Phi29 DNA polymerase is renowned for its processivity in synthesizing single-stranded DNA amplicons by rolling around a circularized DNA template. However, DNA synthesis rolling circle amplification (RCA) is significantly hindered by the secondary structure in the circular template. To overcome this limitation, an engineered circular template without secondary structure could be utilized to improve the sensitivity of RCA-based assays without increasing its complexity.
View Article and Find Full Text PDFBiosensors (Basel)
December 2024
International Research Center for Food and Health, Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai Engineering Research Center of Aquatic-Product Process & Preservation, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
Accurate methods for assessing food freshness through colorimetric pH response play a critical role in determining food spoilage and ensuring food quality standards. This study introduces a novel unlabeled DNA sequence, poly-dA, designed to exploit the colorimetric properties of both the single strand and the fold-back A-motif structure in conjunction with gold nanoparticles (AuNPs) under varying pH conditions. When exposed to storage temperatures of 4 °C and 25 °C, the color variations in the AuNP solution, influenced by pH level changes in mutton and sea bass samples' different storage periods, are easily discernible to the naked eye within a minute.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
Department of Biochemistry, Indian Institute of Science, CV Raman Road, Bengaluru 560012, India.
Saccharomyces cerevisiae meiosis-specific Hop1, a structural constituent of the synaptonemal complex, also facilitates the formation of programmed DNA double-strand breaks and the pairing of homologous chromosomes. Here, we reveal a serendipitous discovery that Hop1 possesses robust DNA-independent ATPase activity, although it lacks recognizable sequence motifs required for ATP binding and hydrolysis. By leveraging molecular docking combined with molecular dynamics simulations and biochemical assays, we identified an ensemble of five amino acid residues in Hop1 that could potentially participate in ATP-binding and hydrolysis.
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