Acid Functionalized Gold Nanoparticles Research Articles

Ellagic acid-enhanced biocompatibility and bioactivity in multilayer core-shell gold nanoparticles for ameliorating myocardial infarction injury

BackgroundMyocardial infarction (MI) is the main contributor to most cardiovascular diseases (CVDs), and the available post-treatment clinical therapeutic options are limited. The development of nanoscale drug delivery systems carrying natural small molecules provides biotherapies that could potentially offer new treatments for reactive oxygen species (ROS)-induced damage in MI. Considering the stability and reduced toxicity of gold-phenolic core-shell nanoparticles, this study aims to develop ellagic acid-functionalized gold nanoparticles (EA-AuNPs) to overcome these limitations.ResultsWe have successfully synthesized EA-AuNPs with enhanced biocompatibility and bioactivity. These core-shell gold nanoparticles exhibit excellent ROS-scavenging activity and high dispersion. The results from a label-free imaging method on optically transparent zebrafish larvae models and micro-CT imaging in mice indicated that EA-AuNPs enable a favorable excretion-based metabolism without overburdening other organs. EA-AuNPs were subsequently applied in cellular oxidative stress models and MI mouse models. We found that they effectively inhibit the expression of apoptosis-related proteins and the elevation of cardiac enzyme activities, thereby ameliorating oxidative stress injuries in MI mice. Further investigations of oxylipin profiles indicated that EA-AuNPs might alleviate myocardial injury by inhibiting ROS-induced oxylipin level alterations, restoring the perturbed anti-inflammatory oxylipins.ConclusionsThese findings collectively emphasized the protective role of EA-AuNPs in myocardial injury, which contributes to the development of innovative gold-phenolic nanoparticles and further advances their potential medical applications.Graphical

Nucleic acid-functionalized gold nanoparticles as intelligent photothermal therapy agents for precise cancer treatment.

We present an intelligent photothermal therapy agents by functionalizing gold nanoparticles with specific nucleic acid sequences. Hairpin nucleic acids are modified to the nanoparticles, forming AuNPs-1 and AuNPs-2. Upon infiltrating cancer cells, these nanoparticles undergo catalytic hairpin assembly in the presence of target miRNA, leading to aggregation and subsequent photothermal conversion. Under near-infrared laser irradiation, aggregated gold nanoparticles exhibit efficient photothermal conversion, selectively damaging cancer cells. This approach offers heightened selectivity, as nanoparticles only aggregate in environments with cancer biomarkers present, sparing normal cells. Cytotoxicity assays confirm minimal toxicity to normal cells. In vivo studies on mice bearing solid tumors validate the system's efficacy in tumor regression. Overall, this study highlights the potential of nucleic acid-functionalized gold nanoparticles in intelligent and selective cancer photothermal therapy, offering insights for targeted diagnosis and treatment development.

Sialic Acid-Functionalized Gold Nanoparticles for Sensitive and Selective Colorimetric Determination of Serotonin

Sialic Acid-Functionalized Gold Nanoparticles for Sensitive and Selective Colorimetric Determination of Serotonin

Formation of lipid corona on Ag nanoparticles and its impact on Ag+ ion dissolution and aggregation of Ag nanoparticles against external stimuli

The application of lipid coated nanoparticles has been expanding in nanoscience over the past few years. Lipid corona formation is one of the novel ways for the lipid conjugation around the nanoparticles. Although several properties of nanoparticles and lipids are well reported in literature in last few years, the dependency of lipid corona formation on metallic core and surface ligands is poorly understood. The aggregation, surface oxidation and metal ions dissolution of nanoparticles limit their usefulness in various applications. Besides all the reported methods to overcome all of these limitations, lipid corona could be an alternative, feasible, and more efficient method. In the current manuscript, we investigate the interaction of aromatic amino acids (tyrosine and tryptophan) functionalized silver nanoparticles (Ag-Tyr and Ag-Trp NPs) with different surface charged and phase states lipid vesicles and compare them with the reported amino acid functionalized gold nanoparticles (Au-AA NPs). The effectiveness of different zwitterionic and positively charged lipid coated Ag-Tyr and Ag-Trp NPs to prevent the aggregation and Ag+ ion dissolution of Ag NPs against different external stimuli (acidic pH, high NaCl concentration, and freeze-thaw cycles) are investigated. Our results reveal that surface ligands around the NPs play crucial role for lipid corona formation irrespective of the metallic core of NPs. Although all the lipid coated Ag NPs exhibit greater stability against external stimuli than native Ag NPs, zwitterionic lipid coated Ag NPs is better choice than positively charged lipid coated Ag NPs. This study on lipid corona and its stability will help the nanoresearcher to choose the suitable lipid for lipid corona formation.

Polyamidoamine-stabilized and hyaluronic acid-functionalized gold nanoparticles for cancer therapy

Gold nanoparticles (AuNPs) are versatile nanomaterials that can be used as drug delivery systems and photothermal agents for cancer therapy. In this study, we developed a novel nanoplatform based on AuNPs using a modified one-pot chemical method for the synthesis of AuNPs using generation 3.0 highly branched biphasic polymeric (polyamidoamine) dendrimers as reducing and stabilizing agent, and hyaluronic acid (HA) as functional moiety. Tetrahydrocurcumin (THC) was chosen for this formulation to be encapsulated in the synthesized AuNPs and their efficacy as nanotherapeutics was investigated in vitro. The developed nanoplatform was characterized by various techniques and evaluated for its drug loading and release, cellular uptake, and cytotoxicity on Caco-2 cells. We found that the nanoplatform had optimal size, charge, stability, and solubility, and showed high encapsulation efficiency of THC. The nanoplatform exhibited pH-responsive drug release and enhanced cellular uptake of THC. The nanoplatform also induced apoptosis in Caco-2 cell line. The HA coating on the nanoplatform improved its biocompatibility and specificity, by facilitating its targeting to CD44 glycoprotein on Caco-2 cells. Our results suggest that the developed nanoplatform is a promising nanotherapeutic strategy for cancer therapy by co-delivering of anti-cancer agents and AuNPs to cancer cells.

Hyaluronic acid-functionalized gold nanoparticles as a cancer diagnostic probe for targeted bioimaging applications

A nanomaterial-based bioimaging method was developed to detect the MCF-7 cancer cells using hyaluronic acid (HA) functionalized-gold nanoparticles/polyetherimide (PEI)-stabilized/rhodamine B (RhB) (AuNPs/PEI/RhB-HA) materials. The fabricated materials have low-toxic nature with exceptional specific attachment to the CD44 receptor overexerted MCF-7-cancer cells. The toxicity test of the materials was evaluated by MTT assay with threshold toxicity concentration of 100 µg/mL. This finding was validated using DAPI staining assay showing no cell death during exposure to nanoparticles. The bioimaging of the AuNPs/PEI/RhB-HA were evaluated by flow cytometry and fluorescence imaging techniques. Also, the cell differentiation of the AuNPs/PEI/RhB-HA was also investigated by incubation with CD44-low expressed HFFF-2 as control group. The uptake percentage of the AuNPs/PEI/RhB-HA nanoparticles for MCF-7 cells were 13.1%, 52.4% and 97.5% for 10 µg/mL, 20 µg/mL and 50 µg/mL after about 4 h of incubation, respectively. However, these values for HFFF-2 cells were around 0.88%, 16.1% and 33.9%, respectively, confirming selective manner of the probe towards CD44-overxeperssed cells. The produced nanoparticles displayed high physical stability with high quantum yield, qualifying the nanoparticles as a brilliant material for in vivo cancer diagnosis aims.

Colorimetric Sensing of Gram-Negative and Gram-Positive Bacteria Using 4-Mercaptophenylboronic Acid-Functionalized Gold Nanoparticles in the Presence of Polyethylene Glycol.

Gold nanoparticles (GNPs) have been used as detection probes for rapid and sensitive detection of various analytes, including bacteria. Here, we demonstrate a simple strategy for bacterial detection using GNPs functionalized with 4-mercaptophenylboronic acid (4-MPBA). 4-MPBA can interact with peptidoglycan or lipopolysaccharides present in bacterial organelles. After the addition of a high concentration of sodium hydroxide (NaOH), the functionalization of the surface of 50 nm GNPs with 4-MPBA (4-MPBA@GNPs) in the presence of polyethylene glycol results in a color change because of the aggregation of 4-MPBA@GNPs. This color change is dependent on the amount of bacteria present in the tested samples. Escherichia coli (E. coli) K-12 and Staphylococcus aureus (S. aureus) are used as Gram-negative and Gram-positive bacterial models, respectively. The color change can be detected within an hour by the naked eye. A linear relationship is observed between bacterial concentrations and the absorbance intensity at 533 nm; R 2 values of 0.9152 and 0.8185 are obtained for E. coli K-12 and S. aureus, respectively. The limit of detection of E. coli K-12 is ∼2.38 × 102 CFU mL-1 and that of S. aureus is ∼4.77 × 103 CFU mL-1. This study provides a promising approach for the rapid detection of target Gram-negative and Gram-positive bacteria.

Insight into the Lysozyme-Induced Aggregation of Aromatic Amino Acid-Functionalized Gold Nanoparticles: Impact of the Protein Conjugation and Lipid Corona on the Aggregation Phenomena.

The aggregation and subsequent precipitation of gold nanoparticles (Au NPs) in the presence of protein molecules restrict the usefulness of NPs in biomedical applications. Till now, the influence of different properties of Au NPs (size, surface charge, surface coatings) and proteins (surface charge, chemical modification, folded and unfolded states) and pH and ionic strength of the solution on the aggregation of both Au NPs and proteins has been thoroughly discussed in the literature. However, the underlying different mechanistic pathways of the protein concentration-dependent aggregation of both Au NPs and proteins are poorly understood. The impact of the lipid corona on the protein-induced Au NP aggregation has remained an unresolved issue. In this context, we investigate the interaction of the negatively charged aromatic amino acid (phenylalanine and tyrosine)-functionalized gold nanoparticles (Au-AA NPs) with the positively charged globular protein lysozyme at different protein concentrations and compare the results with those of conventional citrate-functionalized Au NPs (Au-Cit NPs). Next, we conjugate lipids and proteins to Au NPs to impede the aggregation of Au NPs induced by the lysozyme. Our results reveal that the aggregation mechanism of the Au-AA NPs is distinctly different at low and high protein concentrations with the uniqueness of the Au-AA NPs over the Au-Cit NPs. Furthermore, we find that human serum albumin (HSA) protein-conjugated Au-AA and Au-Cit NPs are more effective in preventing the lysozyme-induced Au NP aggregation than bovine serum albumin (BSA)-conjugated Au NPs. For the first time, we also report the significant role of "hard" and "soft" lipid coronas in the aggregation of amino acid (phenylalanine)-functionalized gold nanoparticles in the presence of lysozyme protein.

An Accurate Sensing Technique for Estimation and Detection of Cr(III) in Water by Using Smartphone

This letter demonstrates a sensing technique for rapid detection and accurate quantification of Chromium(III) in water. The principle of the proposed technique is based on change of color of 3-Mercaptopropionic acid functionalized gold nanoparticle upon interaction with Chromium ion. With the increase in Chromium(III) concentration, color changes occur from red wine to blue. The colorimetric changes are captured by a smartphone for detection and quantification. Images are further processed by using MATLAB software and the concentration of Chromium(III) has been estimated. Chromium(III) concentration as low as 1.99 nM with sensitivity of 0.019 AU/nM has been detected successfully. Furthermore, the effects on the sensor response due to the presence of other interfering metal elements have also been studied. The novelty of the system is in its simple design, low-cost, rapid detection, portability, and easy to use.

Nitrobenzoic acid-functionalized gold nanoparticles: DET promoter of multicopper oxidases and electrocatalyst for NAD-dependent glucose dehydrogenase

We report the synthesis of coated gold nanoparticles with nitrobenzoic moieties (AuNPs-TNB). They displayed small and narrow size distribution (2 nm) as shown by TEM imaging. These functionalized AuNPs-TNB were physically adsorbed on multi-walled carbon nanotubes (MWCNTs) electrodes. Their stable adsorption was monitored by electrochemical methods. The stability of the activated hydroxylamine layer was enhanced compared to the adsorption of the dinitro precursor onto the CNTs layer. Unactivated AuNPs-TNB enhanced the oxygen reduction reaction catalyzed by multicopper oxidases through increased aromatic and electrostatic interactions with limiting current densities higher than 500 µA cm−2. Next, the electrocatalytic properties of the active form toward the oxidation of the reduced form of nicotinamide adenine dinucleotide (NADH) with low overpotential was shown at near neutral pH. Associated with a NAD-dependent glucose dehydrogenase, the bioelectrodes were assessed for glucose electrooxidation. A complete glucose/O2 enzymatic fuel cell was developed based on unactived and activated AuNPs as cathodic DET promoter and anodic electrocatalyst respectively. The nanostructured assembly exhibited efficient glucose oxidation with current densities of 450 µA cm−2 in high glucose concentration and O2 saturated conditions. In concentration close to those found in physiological fluids (0.04 to 4.00 mmol L−1), the enzymatic biofuel cell displayed a linear range for glucose concentration and a low limit of detection (2.5 ± 0.9 µmol L−1).

Thioglycolic acid-functionalized gold nanoparticles: Capping agent-affected color perception stability towards nitrate sensing purpose

In comparison with colorimetric detection of metal ions, inorganic anions sensing on gold nanoparticles (AuNPs) seems to be more challenging and less explored due to their weak affinity towards the surface of such metal nanoparticles. Early efforts to detect nitrate in water mainly focused on amino thiol-functionalized AuNPs, thanks to the gold-sulfur interactions, sometimes adjusting the pH was required. In the present work, thioglycolic acid was preliminarily introduced for functionalizing purpose, in combination with the stability of colloidal AuNPs suspensions capped by either sodium citrate or ascorbic acid, which have not been previously reported. In contrast to the precipitation observed on ascorbic acid-capped AuNPs, the stability of color perception of freshly citrate-capped AuNPs and corresponding functionalized samples during 10 days extended their realistic nitrate sensing applications. A straightforward protocol involving three successive stages (synthesis of AuNPs, functionalizing and colorimetric sensing) exposed the color variations from red to purple and then blue, with the detection limit of nitrate of 50 ppm, qualifying the nitrate limit of drinking water authorized by the World Health Organization (WHO). The color signals were strictly relevant to surface plasmon resonance and particle size, evidenced by ultraviolet – visible spectroscopy (UV–vis) and transmission electron microscopy (TEM), respectively.

Colorimetric detection for uranyl ions in water using vinylphosphonic acid functionalized gold nanoparticles based on smartphone

A simple and portable colorimetric sensor for colorimetric detection of UO22+ in aqueous solution based on vinylphosphonic acid functionalized gold nanoparticles (VPA-AuNPs) has been developed. The VPA-AuNPs solution was prepared by sodium borohydride reduction in the presence of vinylphosphonic acid. The addition of UO22+ would induce aggregation of VPA-AuNPs, resulting in the color change from wine-red to blue, and red-shift of the ultraviolet–visible (UV–vis) spectra. The UO22+ assay based on VPA-AuNPs showed good selectivity and sensitivity, with a limit of detection to be approximately 2.0 μM by naked eyes and 1.07 μM by UV–vis (S/N = 3) respectively. Additionally, a smartphone with a free application named “PhotoMetrix” was employed to estimate the color intensities (red, green, blue value) of VPA-AuNPs in the presence of UO22+ with different concentrations, and the concentration of UO22+ samples could be conveniently exported by the calculated univariate calibration curves. This method shows good feasibility for on-site UO22+ detection in an aqueous solution.

Determinants of gold nanoparticle interactions with Proteins: Off-Target effect study

Photothermal therapy is one of the promising approaches toward cancer treatment. To date, several compounds have been developed for this application, among which nanoparticles are attracting ever-increasing attention. One of the obstacles in developing efficient photothermal nanoparticle agents is their off-target effect which is mainly mediated via non-specific interactions with proteins. Such interaction not only reduces the bioavailability of the agent but also will cause protein aggregation that can be lethal. So, gaining knowledge on the mechanisms mediating such interactions will facilitate development of more effective agents. Our last studies showed the mechanism of action of two modified gold nanoparticles, folic acid functionalized gold nanoparticles (FA-AuNPs) and gold shelled Fe3O4 nanoparticles (AuFeNPs), as photothermal agents. In the current work, we focus on the interaction of these two NPs with human serum albumin (HSA) and human hemoglobin (Hb) as model proteins. The complex formation between NPs and proteins was investigated by fluorescence spectroscopy, dynamic light scattering and circular dichroism. Our data distinguishes the very distinct mode of interaction of charged and neutral NPs with proteins. While the interaction of neutral AuFeNP to proteins is protein dependent, charged nanoparticles FA-AuNP interact indistinguishably with all proteins via electrostatic interactions. Moreover, complexes obtained from FA-AuNPs with proteins are more stable than that of AuFeNP. However, the secondary structure content of proteins in the presence of NPs indicates the insignificant effect of NPs on the secondary structure of these proteins. Our data propose that the charge functionalization of the NPs is an effective way for modulating the interaction of nanoparticles with proteins.

Smartphone-Based Colorimetric Detection of Chromium (VI) by Maleic Acid-Functionalized Gold Nanoparticles

Because of the significant environmental pollution produced by human activities, there is an ongoing need to develop transportable, simple, and reliable techniques for determining trace contaminants on the spot. This work reported a colorimetric detection method for aqueous Cr(VI) sensing by maleic acid-functionalized gold nanoparticles with high sensitivity and selectivity. The wine-red color of the probe solution can change to gray even in the presence of 1.0 µg L−1 of aqueous Cr(VI). Moreover, with the assistance of a smartphone installed with a commercially available color scan application software, its concentration of could be readily quantified on the spot without the help of UV-Vis spectrometer. The detection limit could reach as low as 0.1 µg L−1 with linear range from 0.2 to 2.0 µg L−1. Most importantly, the coefficient variation of the proposed smartphone-based method was equivalent to that of colorimetry, demonstrating the high accuracy of the proposed method for accurate detection of Cr(VI) in resource-constrained countries. Conclusively, with the help of the smartphone, this nanomaterials-based probe demonstrated the potential in the field of environment monitoring for on-site quantitative detection of any pollutants in resource-constrained countries.

Diethylenetriaminepentaacetic Acid-Functionalized Gold Nanoparticles for the Detection of Toxic Chromium Assisted by a Machine-Learning Approach

We present a machine-learning approach in developing a smartphone-based rapid and point-of-use (PoU) trace-level detection of chromium (III and VI) ions using a nanosensor comprising dithiolated diethylenetriaminepentaacetic acid-functionalized gold nanoparticles (DTDTPA-GNP). The bright red color of DTDTPA-GNP turned blue with CrIII/VI ions in an aqueous medium. The nanosensor exhibited good linearity for CrIII/VI detection in a concentration range of 0.001–10 ppm with a detection limit of 0.001 ppm. A smartphone was used to acquire images of the distinct color change due to the DTDTPA-GNP–CrIII/VI interactions. Two features, that is, saturation and chroma component of red color difference were extracted from the color information of the acquired images. The extracted features from training samples were utilized to build a support vector machine-based regression (SVR) model to predict the accurate concentration of chromium (III and VI) in water and an aqueous extract of ferrochrome industrial waste (collected from the alloy industry as waste slag). The accurate prediction of 0.027 ppm CrIII/VI concentration in the industrial waste sample with a 100% recovery rate confirms the colorimetric-based SVR model as an efficient sensing platform for CrIII/VI ion detection. The mean squared error for CrIII/VI prediction was 0.00039 with 404 support vectors and a bias value of 0.1473. This highly selective and sensitive smartphone-based approach thus established the use of DTDTPA-GNP for PoU detection of CrIII/VI, specifically in day-to-day monitoring of water quality.

Selective point-of-care detection of pathogenic bacteria using sialic acid functionalized gold nanoparticles

In resource-limited settings, fast and simple point-of-need tests should facilitate healthcare providers the identification of pathogens avoiding empirical suboptimal treatments with broad-spectrum antibiotics. A rapid optical whole cell bacterial biosensor has been here developed using sialic acid functionalized gold nanoparticles allowing the selective screening of Gram-positive Staphylococcus aureus ATCC 25923 and Methicillin Resistant Staphylococcus aureus (MRSA) USA300 and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 15442) by selecting the appropriate dispersing media. Those bacteria were selected due to their common presence in wound bed tissue of chronic infected topical wounds. The discrimination of bacterial pathogens has been attempted in different media including water, two independent buffers, bacterial broth, human serum and human urine. The identification of Gram + bacterial pathogens was also assessed under simultaneous co-culture of S. Aureus and Pseudomonas aeruginosa. High bacterial loads were required to provide with a statistically significant optical pathogen identification in human serum whereas it was not possible to detect the presence of bacteria at clinically relevant levels in urine.

Underlying Mechanisms for the Modulation of Self-Assembly and the Intrinsic Fluorescent Properties of Amino Acid-Functionalized Gold Nanoparticles.

The origin of the blue fluorescence of proteins and peptides in the visible region has been a subject of intense debate despite several efforts. Although aromatic amino acids, namely tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) are responsible for the intrinsic luminescence of proteins and peptides, the underlying mechanism and contributions of these amino acids to the unusual blue fluorescence are still not well resolved. In the present endeavor, we show that the clusterization of both aromatic and aliphatic amino acids on the surface of the gold nanoparticles (Au NPs) leads to clusteroluminescence, which could be linked to the unusual fluorescence properties of the proteins and peptides and have been ignored in the past. The amino acid monomers initially form small aggregates through clusterization, which provides the fundamental building blocks to establish the amyloid structure as well as the luminescence property. Because of the clusterization, these Au NPs/nano-aggregate systems are also found to exhibit remarkable stability against the freeze-thaw cycle and several other external stimuli, which can be useful for biological and biomedical applications.

Interaction of Aromatic Amino Acid-Functionalized Gold Nanoparticles with Lipid Bilayers: Insight into the Emergence of Novel Lipid Corona Formation

The coating of proteins and lipids around the surface of the nanoparticles is known as "protein corona" and "lipid corona", respectively, which have promising biomedical applications. While protein corona formation is well-known, the lipid corona is relatively new and its stability is yet to be explored. In the present contribution, we report a novel lipid corona formation and its underlying mechanism using aromatic amino acid-functionalized gold nanoparticles (Au-AA NPs) as a template by means of spectroscopic (steady-state UV-visible and fluorescence) and imaging (CLSM, HR-TEM, and AFM) techniques. Our study demonstrates that in the presence of high lipid concentration Au-AA NPs intrinsically tow the lipid molecules from the lipid vesicles and decorate themselves by lipid leading to unique lipid corona formation. In contrast, at low lipid concentration Au-AA NPs undergo lipid-induced aggregation. The lipid-nanoparticle interaction is a time-dependent phenomenon and depends on the surface charge of both the lipid and the Au-AA NPs. The HR-TEM analysis indicates that the partial lipid coating is an intermediate step of lipid-induced aggregation and lipid corona formation of the Au-AA NPs. Significantly, we found that the colloidal property of these lipid-coated nanoparticles (lipid corona) is immune to resist extreme harsh conditions, that is, high acidic pH, several repetitive freeze-thaw cycles, and high salt concentration. The extra stability of Au-AA NPs upon the formation of lipid corona allows us to introduce new engineered nanoparticles for future prospective.

Selective colorimetric sensing of deferoxamine with 4-mercaptophenol- and mercaptoacetic acid-functionalized gold nanoparticles via Fe(iii) chelation

The multidentate deferoxamine ligand can selectively aggregate the Fe(iii)-attached AuNPs@(4MP–MAA) colorimetric nanoprobe, whereas other bidentate iron chelators cannot bridge the nanoparticles.

Microsensor Based on Gold Nanoparticles for Fast and Sensitive Ortho-Xylene Detection

Miniaturization of gas sensors carries added benefits of better portability, lower costs, and allowing for multianalyte detection by integrating various sensors in one device. In this study, laser writing technology is proposed to fabricate a micro gas sensor based on 11-mercaptoundecanoic acid functionalized gold nanoparticles, which are assembled and deposited over the spacing between two electrodes. During the response process to volatile organic compounds (VOCs), conductivity change is dominated by interparticle properties, such as dielectric constant, interparticle spacing. The microsensor showed the maximum response to ortho-xylene among seven target analytes. The microsensor exhibited larger response ( $\Delta \text{R}/\text{R}_{a}= 0.412$ ) than the drop-cast film ( $\Delta \text{R}/\text{R}_{a} = 0.044$ ) at 5000 ppm for ortho-xylene. The response time of the microsensor was 57 s, shorter than the drop-cast film of 127 s. Improved sensitivity and shorter response time were also observed for other VOCs (toluene, ethanol, benzene, methanol, acetone, chloroform). The better sensing performance can be attributed to the larger surface-volume ratio brought by the rough surface and the miniaturization of device. Therefore, the shorter response time and higher response were obtained by laser writing technology.