Microchimica Acta最新文献

Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is a powerful tool for metallic nanoparticle (NP) characterisation in terms of concentration and, taking into account several assumptions, also size. However, this technique faces challenges, such as the intrinsic matrix effect, which significantly impact the results when analysing real complex samples. This issue is critical for the calculations of key SP-ICP-MS parameters ultimately altering the final outcomes. Novel analytical approaches with high metrological quality such as isotope dilution analysis (IDA) can overcome these limitations by improving signal discrimination in challenging SP-ICP-MS scenarios. This alternative has mainly been applied for NP size characterisation but remains underexplored in modern ICP-MS and SP set-ups. Thus, the implementation of a revised version of IDA-SP-ICP-MS, including recent advances in quadrupole ICP-MS and SP data processing, which enables reliable NP sizing and counting, would be of utmost interest. In this work, this combination using the species-unspecific IDA mode has been investigated as an alternative to tackle matrix effect caused by complex matrices with platinum NPs as a case study. The optimum ionic tracer concentration has been evaluated for different PtNP sizes, resulting in a range of 500 to 1000 ng L⁻¹ due to differences in the mean NP signal. A valuable in-house spreadsheet for the data treatment has also been developed. The successful applicability of the methodology for determining the size and particle number concentration of 30 and 50 nm PtNPs has been demonstrated not only in environmental samples (synthetic and natural seawater), but also, for the first time, in biological matrices such as cell culture media and human urine.

Graphical Abstract

A novel electrochemiluminescence (ECL) biosensor was developed for the ultrasensitive detection of miRNA-155, based on the synergistic combination of multifunctional nanomaterials. The biosensor employed a conductive metal–organic framework (MOF), Ni₃(HAB)₂ (HAB = hexaaminobenzene), as the substrate material. The unique π-electron conjugated structure of Ni₃(HAB)₂ endowed the biosensor with excellent electron transport properties, significantly enhancing its sensitivity. Furthermore, the innovative preparation of Au@ZnNiAl-LDH nanocomposites, characterized by a high specific surface area was employed to synergistically enhance the catalytic performance of the biosensor in conjunction with Ni₃(HAB)₂. The Au@ZnNiAl-LDH also provided stable anchoring sites for the capture unit, comprised of a DNA tetrahedron hairpin composite structure (DT-HP). Additionally, a porous aluminum-based metal–organic framework (MIL-53(Al)-NH₂) was utilized to encapsulate Ru(bpy)₃²⁺, constructing a Ru@MIL-53(Al)-NH₂ signal unit that effectively improved the stability of the ECL signal. Under optimal conditions, the ECL intensity of the biosensor exhibited a robust linear relationship with the logarithm of miRNA-155 concentration over a range 3 fM to 1 nM, achieving a detection limit as low as 0.9 fM. Moreover, the biosensor demonstrated exceptional specificity, selectivity, and stability, highlighting its significant potential for applications in bioanalysis and clinical diagnosis, particularly for the early diagnosis of tumor.

Graphical Abstract

A triple signal amplified electrochemical aptasensor for the detection of bisphenol A (BPA) was developed for the first time based on gold nanoparticles (AuNPs), hemin/G-quadruplex DNAzyme, and exonuclease I (Exo I) assisted amplification strategies. The BPA aptamer (Apt) hybridized with the capture probe (CP) was fixed on the gold electrode (GE) to form the double-stranded DNA (dsDNA) structure. When BPA was present, the Apt was detached from the GE surface by specific recognition between the BPA and Apt, forming BPA-Apt complexes in solution. The complexes could be selectively digested by Exo I, releasing BPA to participate in the cycle for binding to other Apt in dsDNA. The hybridization of the CP and auxiliary DNA (aDNA) within the detect probe DNA (dpDNA)-AuNP-aDNA nanocomplex allowed the nanocomplex to connect to the GE surface. The dpDNA interacted with K⁺ and hemin to produce hemin/G-quadruplex DNAzyme, which catalyzed H₂O₂ reduction, accelerated methylene blue (MB) oxidization, and further amplified the electrochemical signal. The integration of triple signal amplification strategies with aptamer-specific recognition enabled sensitive and specific detection of BPA. Under optimized conditions, the aptasensor exhibited a linear range of 0.1 pM–10 nM, with a low detection limit of 76 fM. Moreover, the designed aptasensor was successfully applied to detect BPA in lake water, fruit juice, and honey samples.

Graphical Abstract

A pasting-3D microfluidic paper-based analytical device (P-3D μPAD) was developed. It enabled an efficient cascade reaction between urate oxidase (UOX) and Fe/Pt-doped carbon nanoparticles (Fe/Pt-CNPs) for visual colorimetric detection of uric acid (UA). The novel Fe/Pt-CNP nanozyme performed high peroxidase-like activity toward 3,3′,5,5′-tetramethylbenzidine (TMB) and H₂O₂ with Michaelis − Menten constants (K_m) of 0.97 and 2.30 mM, respectively. The UOX-Fe/Pt-CNP system was incorporated into P-3D μPAD: the 1st layer was UOX hydrolysis reaction under alkaline pH, and the 2nd layer was Fe/Pt-CNPs catalyzing H₂O₂ to oxidize TMB at acidic pH. The separated two layers allowed cascade reaction under different working pH without sacrificing the activity of UOX or Fe/Pt-CNPs. The images were captured and analyzed by the camera and “Color Recognition” application using a  smartphone. The linear range of P-3D μPAD for UA was 25–1000 μM with a limit of detection of 10 μM which met the requirements for clinical applications. The high accuracy of P-3D μPAD for UA detection in invasive (blood) and noninvasive (saliva) samples has been confirmed by the biochemical analyzer. This work offers a sensitive, flexible, affordable, and disposable tool for on-site UA level monitoring and provides new insight into natural enzyme and nanozyme tandem systems for biosensing.

Gold nanoclusters decorated hollow ZIF-8 encapsulating iron-catecholates (Fe-HHTP@HZIF-8@ AuNCs) was formed through self-assembly of Fe³⁺ and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), in situ embedding of ZIF-8, and Au³⁺-Zn²⁺ exchange reaction. Its morphology and structure were fully characterized by high-resolution transmission electron microscopy, X-ray diffraction, transmission electron microscopy element mapping, and X-ray photoelectron spectroscopy. Additionally, its oxidase-like activity was explored with K_m of 0.21 mM and V_max of 1.74 × 10⁻⁶ M·s⁻¹ toward 3,3′,5,5′-tetramethylbenzidine (TMB). Due to its excellent catalytic activity and nitrite mediated diazotization of oxTMB, a ratiometric colorimetric method for nitrite detection was established and validated with wide linear range (2.0–400.0 μM), low LOD (0.12 μM), high accuracy (recovery of 95.11–102.14%), and good selectivity. This method was then utilized to determine the nitrite content in sausages and tap water. This study provided a new idea for developing efficient nanozymes and offered an accurate approach for nitrite determination.

Graphical Abstract

A novel glycoprotein assay was developed by integrating the hairpin aptamer (H-APT)–mediated glycoprotein recognition and the reactive oxygen species–sensitive microcapsule (ROS-MC)–induced signal amplification. The analyzing process begins with the transfer of the target glycoprotein to a chlorin e6 (Ce6)–labeled DNA sequence via H-APT-mediated DNA displacement. Subsequently, the Ce6-labeled DNA was used to induce the disassembly of fluorophore-loaded ROS-MC under 650-nm light irradiation. Leveraging the rapid release of the fluorophore and the high loading capacity of the MC, this glycoprotein assay is capable of quantifying glycoprotein content in native biofluids within 2.5 h, achieving a detection limit of 0.034 ng/mL. We applied this assay to determine the glycoprotein composition in plasma samples of colorectal cancer patients, revealing a significant increase in glycoprotein content for those with a poor prognosis. In summary, we have developed an innovative method for glycoprotein determination that shows potential for clinical translation.

Graphical abstract

Antibiotic resistance genes (ARGs) pose serious threats to environmental and public health, and monitoring ARGs in wastewater is a growing need because wastewater is an important source. Microfluidic devices can integrate basic functional units involved in sample assays on a small chip, through the precise control and manipulation of micro/nanofluids in micro/nanoscale spaces, demonstrating the great potential of ARGs detection in wastewater. Here, we (1) summarize the state of the art in microfluidics for recognizing ARGs, (2) determine the strengths and weaknesses of portable microfluidic chips, and (3) assess the potential of portable microfluidic chips to detect ARGs in wastewater. Isothermal nucleic acid amplification and CRISPR/Cas are two commonly used identification elements for the microfluidic detection of ARGs. The former has better sensitivity due to amplification, but false positives due to inappropriate primer design and contamination; the latter has better specificity. The combination of the two can achieve complementarity to a certain extent. Compared with traditional microfluidic chips, low-cost and biocompatible paper-based microfluidics is a very attractive test for ARGs, whose fluid flow in paper does not require external force, but it is weaker in terms of repeatability and high-throughput detection. Due to that only a handful of portable microfluidics detect ARGs in wastewater, fabricating high-throughput microfluidic chips, developing and optimizing recognition techniques for the highly selective and sensitive identification and quantification of a wide range of ARGs in complex wastewater matrices are needed.

Graphical Abstract

A dual supersaturation recrystallization method was employed to synthesize water-stable, highly sensitive cesium-lead halide perovskite nanocrystals (CsPbBr₃ PNCs). The PNCs exhibited excellent water stability, a significant photoluminescence quantum efficiency of 83.03%, along with a narrow full width at half maximum (FWHM) of 20 nm. Following iodide ion treatment, the fluorescence emission peak of CsPbBr₃ PNCs can be tuned from 520 to 681 nm, causing a color transition from green to red. Within the 0–300 μM range, the red shift showed a linear correlation with I⁻ concentration, achieving a detection limit as low as 0.40 μM. It is worth noting that excessive iodide ions could have allowed PNCs to exhibit dual emission with maximum wavelengths of 520 and 681 nm. A ratiometric perovskite nanoprobe was constructed with the green emission peak as an internal standard and the red emission peak as the response signal. The probe demonstrated a strong linear correlation with tetracycline concentrations ranging from 0 to 8 μM, with a detection limit of 88.60 nM (S/N = 3). This research offers valuable insights into the design and development of ratiometric perovskite sensors capable of detecting in aqueous solutions, while also emphasizing the importance of rapidly establishing hydrogen-bonding networks when analyzing such detection systems.

Graphical abstract

An efficient dual-state blue-emitting zinc-based metal–organic frameworks (MOFs), designated as UoZ-8 has been developed. Coordination-induced emission causes the UoZ-8 to give the blue emission in both solid and dispersed form in liquid. Upon the addition of tetracycline (TC), a noticeable shift from blue emission to greenish-yellow emission occurred, with a marked increase in intensity, which was attributed to the inner filter effect accompanied by aggregation-induced emission (IFE-AIE). Consequently, ratiometric-based fluorometry (in solution) and color tonality visual detection platform (on paper) were developed, exploiting the dual-state property of UoZ-8 alone and UoZ-8:TC. The detection limit using the ratiometric-based fluorescence method was 3.8 nM, while on paper it was 3.5 µM. Paper-based visual mode was used for the detection of TC in tap and river water samples showing satisfactory accuracy and precision.

Graphical Abstract