High Stability Au NPs: From Design to Application in Nanomedicine

Localization of fluorescent gold nanoparticles throughout the eye after topical administration

The human eye is a highly intricate sensory organ. When a condition requiring treatment occurs, eyedrops, which represent 90% of all ophthalmic treatments, are most frequently used. However, eyedrops are associated with low bioavailability, with less than 0.02% of therapeutic molecules reaching the anterior chamber. Thus, new delivery systems are required to ensure sufficient drug concentration over time at the target site. Gold nanoparticles are a promising avenue for drug delivery; however, they can be difficult to track in biological systems. Fluorescent gold nanoparticles, which have the same ultrastability and biocompatibility as their nonfluorescent counterpart, could act as an effective imaging tool to study their localization throughout the eye after administration. Thus, this study (1) synthesized and characterized fluorescent gold nanoparticles, (2) validated similar properties between nonfluorescent and fluorescent gold nanoparticles, and (3) determined their localization in the eye after topical application on ex vivo rabbit eyes. The fluorescent gold nanoparticles were synthesized, characterized, and identified in the cornea, iris, lens, and posterior segment of rabbit eyeballs, demonstrating tremendous potential for future drug delivery research.

Sericin-Assisted Green Synthesis of Gold Nanoparticles as Broad-Spectrum Antimicrobial and Biofilm-Disrupting Agents for Therapy of Bacterial Infection

Background

Tens of millions of people die from wound infections globally each year, and nearly 80% of tissue infections are associated with bacterial biofilms. However, overuse of antibiotics can lead to bacterial resistance. Therefore, it is critical to develop simple and effective strategies to kill bacteria and remove biofilms.

Methods

The present study used sericin as a reducing and stabilizing agent to synthesize sericin-gold nanoparticles (Ser-Au NPs) and tested its colloidal stability under different pH and salt concentration conditions. Subsequently, functional gold nanocomposites (Ser-Au@MMI) were synthesized by combining Ser-Au NPs with 2-mercapto-1-methylimidazole (MMI). The antimicrobial effect of Ser-Au@MMI was checked by MIC, antimicrobial activity test, and in vitro cytotoxicity was assessed using CCK-8 assay. In vitro anti-biofilm effect was observed by fluorescence microscopy and SEM. Finally, the anti-infective therapeutic efficacy of Ser-Au@MMI was determined in an in vivo rat-infected wound model.

Results

Sericin as a reducing and stabilizing agent to synthesize Ser-Au NPs exhibited excellent colloidal stability under different pH and salt concentration conditions. The TEM, EDS, and XPS analyses confirmed the successful synthesis of Ser-Au@MMI. It exhibited higher antibacterial activity due to the synergistic effect of MMI and AuNP, which can achieve a bactericidal effect by destroying the integrity of bacterial cell walls and structure. In addition, Ser-Au@MMI10 (HAuCl4:MMI =1:10) concentration (64 μg/mL) could effectively disrupt biofilms formed by four species of bacteria and kill them, including P. aeruginosa, B. subtilis, E. coli, and S. aureus, but was not cytotoxic to mouse fibroblasts (L929) cells. Infected wound modeling showed that Ser-Au@MMI10 accelerated infected wound healing in vivo.

Conclusion

Ser-Au@MMI nanocomposites are prepared through a facile and environmentally friendly strategy and have the advantages of excellent bactericidal effect and low toxicity, which has the potential for application as a broad-spectrum antimicrobial agent and biofilm disrupting agent in healthcare.

Antibody screening-assisted multichannel nanoplasmonic sensing chip based on SERS for viral screening and variants identification

The Omicron variants of SARS-CoV-2 have been spreading globally and have never disappeared from our sight, indicating that their coexistence with humans has become a fact, and monitoring its evolution and spread remains a current task. Although polymerase chain reaction (PCR) is the most commonly used virus detection method, it requires labor-intensive and time-consuming procedures in a laboratory setting. Herein, a multichannel nanoplasmonic sensing chip based on surface enhanced Raman spectroscopy (SERS) was developed for detecting N and S proteins, as well as IgG and IgM, related to SARS-CoV-2 Omicron variants. Through a self-screening process, specific antibodies for on-site and rapid identification of important variants of concern (VoCs) were obtained, and their binding was confirmed by protein structure analysis. The use of these S protein specific antibodies can accurately identify Omicron VoCs (BA. 5, BF.7，XBB.1.5) with the detection limit (LoD) of 0.16 pg/mL. Then, the proposed SERS array chip was integrated with a hand-held Raman spectrometer to successfully detect the Omicron subvariants in real saliva samples within only 20 min, greatly reducing the detection time of PCR. This sensing technology will provide a powerful and rapid point-of-care testing (POCT) method for virus diagnosis, subtype identification, and post-infection antibody level monitoring.

The abscopal effects of sonodynamic therapy in cancer

The abscopal effect is a phenomenon wherein localised therapy on the primary tumour leads to regression of distal metastatic growths. Interestingly, various pre-clinical studies utilising sonodynamic therapy (SDT) have reported significant abscopal effects, however, the mechanism remains largely enigmatic. SDT is an emerging non-invasive cancer treatment that uses focussed ultrasound (FUS) and a sonosensitiser to induce tumour cell death. To expand our understanding of abscopal effects of SDT, we have summarised the preclinical studies that have found SDT-induced abscopal responses across various cancer models, using diverse combination strategies with nanomaterials, microbubbles, chemotherapy, and immune checkpoint inhibitors. Additionally, we shed light on the molecular and immunological mechanisms underpinning SDT-induced primary and metastatic tumour cell death, as well as the role and efficacy of different sonosensitisers. Notably, the observed abscopal effects underscore the need for continued investigation into the SDT-induced 'vaccine-effect' as a potential strategy for enhancing systemic anti-tumour immunity and combating metastatic disease. The results of the first SDT human clinical trials are much awaited and are hoped to enable the further evaluation of the safety and efficacy of SDT, paving the way for future studies specifically designed to explore the potential of translating SDT-induced abscopal effects into clinical reality.

Current Landscape and Future Directions in Cancer Immunotherapy: Therapies, Trials, and Challenges

Cancer remains a leading global health challenge, placing immense burdens on individuals and healthcare systems. Despite advancements in traditional treatments, significant limitations persist, including treatment resistance, severe side effects, and disease recurrence. Immunotherapy has emerged as a promising alternative, leveraging the immune system to target and eliminate tumour cells. However, challenges such as immunotherapy resistance, patient response variability, and the need for improved biomarkers limit its widespread success. This review provides a comprehensive analysis of the current landscape of cancer immunotherapy, highlighting both FDA-approved therapies and novel approaches in clinical development. It explores immune checkpoint inhibitors, cell and gene therapies, monoclonal antibodies, and nanotechnology-driven strategies, offering insights into their mechanisms, efficacy, and limitations. By integrating emerging research and clinical advancements, this review underscores the need for continued innovation to optimise cancer immunotherapy and overcome existing treatment barriers.

Targeted delivery of curcumin and CM11 peptide against hepatocellular carcinoma cells based on binding affinity of PreS1-coated chitosan nanoparticles to SB3 protein

In recent years, the use of cationic peptides as alternative drugs with anticancer activity has received attention. In this study, the targeted release of curcumin (Cur) and CM11 peptide alone and together against hepatocellular carcinoma (HCC) was evaluated using chitosan nanoparticles (CS NPs) coated with Pres1 that target the SB3 antigen of HCC cells (PreS1-Cur-CM11-CS NPs). SB3 protein is the specific antigen of HCC and the PreS1 peptide is a part of the hepatitis B antigen, which can specifically bind to the SB3 protein. Chitosan was used to prepare NPs. To Cur and CM11 loading, drugs were added to the CS solution in appropriate concentrations. Pres1 was coupled to the surface of the NPs using EDC catalyst to target NPs against HepG2 cells. SEM and DLS analysis confirmed that the PreS1-Cur-CM11-CS NPs had a size of about 132 nm, the ideal size for penetrating the cell membrane. The loading of Cur and CM11 was equal to 87% and 65%, respectively, which had a sustained and better release in the acidic environment than in the physiological environment. The MTT assay showed that PreS1-Cur-CM11-CS NPs act in a targeted and specific manner with the highest toxicity on the HepG2 cells compared to the control by a decrease in viability of about 26% after 48 h based on cell apoptosis. The results showed that PreS1-Cur-CM11-CS NPs are capable of targeted and specific drug release against HepG2 cancer cells and have significant potential to fight this cancer.

Auricularia Auricula Polysaccharide-Mediated Green Synthesis of Highly Stable Au NPs

Polysaccharide-functionalized gold nanoparticles (Au NPs) exhibit a promising application in biomedical fields due to their excellent stability and functional properties. The Au NPs from Auricularia auricula polysaccharide (AAP) were successfully synthesized using a straightforward method. By controlling the mass fraction of AAP, pH, reaction temperature, reaction time, and concentration of gold precursor, the highly dispersed spherical AAP-functionalized Au NPs (AAP-Au NPs) were prepared. The Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS) indicated that the synthesis mechanism of AAP-Au NPs was as follows: the molecular chain of AAP undergoes a glycosidic bond breakage to expose the reduction terminus in the presence of gold precursor, which reduced Au(III) to Au(0), and itself was oxidized to carboxylate compounds for maintaining the stability of AAP-Au NPs. Additionally, based on the electrostatic interactions and steric forces, as-prepared AAP-Au NPs exhibit excellent stability at various pH (5–11), temperature (25–60 °C), 5 mmol/L glutathione, and 0.1 mol/L Na+ and K+ solutions. Furthermore, AAP-Au NPs retained the ability to scavenge DDPH and ABTS radicals, which is expected to expand the application of Au NPs in biomedical fields.

Ultrasound-Driven Deposition of Au and Ag Nanoparticles on Citrus Pectin: Preparation and Characterisation of Antimicrobial Composites

Pectin is a renewable, non-toxic and biodegradable polymer made of galacturonic acid units. Its polar groups make it suitable for complexing and supporting metallic nanoparticles (NPs). This work aimed to produce antibacterial nanocomposites using pectin and acoustic cavitation. The metal NPs (Au or Ag) were deposited using ultrasound (US, 21 kHz, 50 W) and compared with those achieved with mechanical stirring. The impact of the reducing agents (NaBH4, ascorbic acid) on the dispersion and morphology of the resulting NPs was also assessed. Characterization by diffuse reflectance (DR) UV-Vis-NIR spectroscopy and field emission scanning electron microscopy (FESEM) showed that the use of US improves the dispersion and decreases the size of both Au and Ag NPs. Moreover, with Au NPs, avoiding external reductants led to smaller NPs and more uniform in size. The prepared NPs were functionalized with oxytetracycline in water and tested against Escherichia coli (gram negative) and Staphylococcus epidermidis (gram positive) via the Kirby-Bauer test. The results show a better antibacterial activity of the functionalized nanoparticles compared to antibiotic-free NPs and pure oxytetracycline, advising the potential of the nanoparticles as drug carriers. These findings underscore the significance of US-assisted synthesis, paving the way to new environmentally friendly antimicrobial materials.

Effects of Gold Nanoparticles on Mentha spicata L., Soil Microbiota, and Human Health Risks: Impact of Exposure Routes

Nanoparticles, due to their extensive production and application, can have significant consequences for the environment, including soil and plant pollution. Therefore, it is very important to assess how nanoparticles will affect plants depending on the exposure pathways. The effect of gold nanoparticles in a concentration range of 1-100 mg/L on Mentha spicata L. during a 28-day experiment was investigated. Two routes of nanoparticles exposure were applied: root and foliar. Transmission electron microscopy was used to characterize nanoparticles and their effect on plant leaves' ultrastructure. Gold content in soil and plant segments was determined using k0-neutron activation analysis. For root exposure, gold was mainly accumulated in soil (15.2-1769 mg/kg) followed by root systems (2.99-454 mg/kg). The maximum accumulation of gold in leaves (5.49 mg/kg) was attained at a nanoparticle concentration of 100 mg/L. Foliar exposure resulted in the maximum uptake of gold in leaves (552 mg/kg) and stems (18.4 mg/kg) at the highest applied nanoparticle concentration. The effect of nanoparticles on the Mentha spicata L. leaves' biochemical composition was assessed. Nanoparticles affected the content of chlorophyll and carotenoids and led to an increase in antioxidant activity. Root exposure to gold nanoparticles resulted in an increase in the number of starch grains in chloroplasts and also suppressed the activity of the soil microbiota. Gold extraction from mint leaves into herbal infusion varied from 2 to 90% depending on the concentration of nanoparticles in the solution and the exposure route. The health risk as a result of gold exposure via herbal tea intake was assessed through estimated daily intake. The hazard quotient values were found to be less than the cutoff, indicating that a cup of tea infusion should not cause a serious impact to human health.

HAuCl4-mediated green synthesis of highly stable Au NPs from natural active polysaccharides: Synthetic mechanism and antioxidant property

Polysaccharide-functionalized gold nanoparticles (Polysaccharide-Au NPs) with high stability were successfully prepared by a straightforward method. Notably, the Au (III) ion acts as a strong Lewis acid to facilitate glycosidic bond breaking. Subsequently, the polysaccharide conformation was transformed to an open-chain form, exposing highly reduced aldehyde or ketone groups that reduce Au (III) to Au (0) crystal species, further growing into Au NPs. As-prepared Au NPs displayed excellent stability over a longer storage period (more than 70 days), a wide range of temperatures (25-60 °C), and pH range (3-11), varying concentrations (0-200 mM) and types of salt ions (Na+, K+, Ca2+, Mg2+), and glutathione solutions (5 mM). More interestingly, polysaccharide-Au NPs retained the antioxidant activity of polysaccharides and reduced oxidative damage at the cellular level through decreased reactive oxygen species (ROS) production. The intracellular levels of ROS pretreated with polysaccharide and polysaccharide-Au NPs were decreased 53.12-75.85 % compared to the H2O2 group, respectively. Therefore, the green synthesized Au NPs from natural active polysaccharides exhibit potential applications in biomedical fields.

Surface engineered nanohybrids in plasmonic photothermal therapy for cancer: Regulatory and translational challenges

Plasmonic materials as non-invasive and selective treatment strategies are gaining increasing attention in the healthcare sector due to their remarkable optical and electronic properties, where the interface between matter and light becomes enhanced and highly localized. Some attractive applications of plasmonic materials in healthcare include drug delivery to target specific tissues or cells, hence reducing the side effects of the drug and improving their efficacy; enhancing the contrast and resolution in bioimaging; and selectively heating and destroying the cancerous cells while parting the healthy cells. Despite such advancements in photothermal therapy for cancer treatment, some limitations are still challenging. These include poor photothermal conversion efficiency, heat resistance, less accumulation in the tumor microenvironment, poor biosafety of photothermal agents, damage to the surrounding healthy tissues, post-treatment inflammatory responses, etc. Even though the clinical application of photothermal therapy is primarily restricted due to poor tissue penetration of excitation light, enzyme therapy is hindered due to less therapeutic efficacy. Several multimodal strategies, including chemotherapy, radiotherapy, photodynamic therapy, and immunotherapy were developed to circumvent these side effects associated with plasmonic photothermal agents for effective mild-temperature photothermal therapy. It can be prophesied that the nanohybrid platform could pave the way for developing cutting-edge multifunctional precise nanomedicine via an ecologically sustainable approach towards cancer therapy. In the present review, we have highlighted the significant challenges of photothermal therapy from the laboratory to the clinical setting and their struggle to get approval from the Food and Drug Administration (FDA).

Polysaccharide-based gold nanomaterials: Synthesis mechanism, polysaccharide structure-effect, and anticancer activity

Polysaccharide-based gold nanomaterials have attracted great interest in biomedical fields such as cancer therapy and immunomodulation due to their prolonged residence time in vivo and enhanced immune response. This review aims to provide an up-to-date and comprehensive summary of polysaccharide-based Au NMs synthesis, including mechanisms, polysaccharide structure-effects, and anticancer activity. Firstly, research progress on the synthesis mechanism of polysaccharide-based Au NMs was addressed, which included three types based on the variety of polysaccharides and reaction environment: breaking of glycosidic bonds via Au (III) or base-mediated production of highly reduced intermediates, reduction of free hydroxyl groups in polysaccharide molecules, and reduction of free amino groups in polysaccharide molecules. Then, the potential effects of polysaccharide structure characteristics (molecular weight, composition of monosaccharides, functional groups, glycosidic bonds, and chain conformation) and reaction conditions (the reaction temperature, reaction time, pH, concentration of gold precursor and polysaccharides) on the size and shape of Au NMs were explored. Finally, the current status of polysaccharide-based Au NMs cancer therapy was summarized before reaching our conclusions and perspectives.

Chitosan-Based Nano Systems for Natural Antioxidants in Breast Cancer Therapy

Breast cancer is a major cause of death globally, accounting for around 13% of all deaths. Chemotherapy, the common treatment for cancer, can have side effects that lead to the production of reactive oxygen species (ROS) and an increase in oxidative stress in the body. Antioxidants are important for maintaining the health of cells and helping the immune system function properly. They play a crucial role in balancing the body's internal environment. Using natural antioxidants is an alternative to mitigate the harmful effects of oxidative stress. However, around 80% of natural antioxidants have limited effectiveness when taken orally because they do not dissolve well in water or other solvents. This poor solubility affects their ability to be absorbed by the body and limits their bioavailability. One strategy that has been considered is to increase their water solubility to increase their oral bioavailability. Chitosan-based nanoparticle (CSNP) systems have been extensively explored due to their reliability and simpler synthesis routes. This review focuses on the various methods of chitosan-based nanoformulation for developing effective oral dosage forms for natural antioxidants based on the pharmacokinetics and pharmacodynamics properties. Chitosan (CS) could be a model, because of its wide use in polymeric NPs research, thus providing a better understanding of the role of vehicles that carry natural antioxidants in maintaining the stability and enhancing the performance of cancer drugs.

Features of Copper and Gold Nanoparticle Translocation in Petroselinum crispum Segments

The application of metal nanoparticles in industry and medicine results in their release into the environment, which can have a negative impact on human health. The effects of gold (AuNPs) and copper (CuNPs) nanoparticles at the concentration range of 1-200 mg/L on parsley (Petroselinum crispum) under conditions of root exposure and their translocation in roots and leaves were investigated in a 10-day experiment. The content of copper and gold in soil and plant segments was determined using ICP-OES and ICP-MS techniques, while the morphology of nanoparticles was analyzed using transmission electron microscopy. Differences in the nanoparticle uptake and translocation were observed: CuNPs mainly accumulated in soil (4.4-465 mg/kg), while accumulation in the leaves were at the control level. AuNPs mainly accumulated in soil (0.04-108 mg/kg), followed by roots (0.05-45 mg/kg) and leaves (0.16-53 mg/kg). The influence of AuNPs and CuNPs on the biochemical parameters of parsley was on the content of carotenoids, the levels of chlorophyll, and antioxidant activity. Application of CuNPs even at the lowest concentration led to a significant reduction in carotenoids and total chlorophyll content. AuNPs at low concentrations promoted an increase in the content of carotenoids; however, they also significantly reduced it at concentrations higher than 10 mg/L. To our knowledge, this is the first study of the effect of metal nanoparticles on parsley.

Synergistic Role of Temperature and Salinity in Aggregation of Nonionic Surfactant-Coated Silica Nanoparticles

The adsorption of nonionic surfactants onto hydrophilic nanoparticles (NPs) is anticipated to increase their stability in aqueous medium. While nonionic surfactants show salinity- and temperature-dependent bulk phase behavior in water, the effects of these two solvent parameters on surfactant adsorption and self-assembly onto NPs are poorly understood. In this study, we combine adsorption isotherms, dispersion transmittance, and small-angle neutron scattering (SANS) to investigate the effects of salinity and temperature on the adsorption of pentaethylene glycol monododecyl ether (C₁₂E₅) surfactant on silica NPs. We find an increase in the amount of surfactant adsorbed onto the NPs with increasing temperature and salinity. Based on SANS measurements and corresponding analysis using computational reverse-engineering analysis of scattering experiments (CREASE), we show that the increase in salinity and temperature results in the aggregation of silica NPs. We further demonstrate the non-monotonic changes in viscosity for the C₁₂E₅-silica NP mixture with increasing temperature and salinity and correlate the observations to the aggregated state of NPs. The study provides a fundamental understanding of the configuration and phase transition of the surfactant-coated NPs and presents a strategy to manipulate the viscosity of such dispersion using temperature as a stimulus.

Tuning size and shape of gold nanoparticles using seed-mediated growth by unfocused femtosecond laser-induced plasma

Gold nanoparticles with tunable size and shape are effectively synthesized with a femtosecond laser using the seed and growth method by reducing a KAuCl₄ solution with polyvinylpyrrolidone (PVP) surfactant as a stabilizer. The sizes of gold nanoparticles, including 7.30 to 9.90, 11.0, 12.0, 14.1, 17.3, 22, 23.0, 24.4, and 27.2 nm, are effectively altered. In addition, the initial shapes of gold nanoparticles (quasi-spherical, triangular, and nanoplate) are also successfully changed. While the reduction effect of an unfocused femtosecond laser can control the size of nanoparticles, the surfactant can influence the growth of nanoparticles and determine their shape. This technology represents a breakthrough for nanoparticle development by not employing strong reducing agents and instead using an environmentally friendly synthesis technique.

Monomeric and Polymeric Mesoionic N-Heterocyclic Carbene-Tethered Silver Nanoparticles: Synthesis, Stability, and Catalytic Activity

In recent years, N-heterocyclic carbenes (NHCs) have garnered significant attention as promising alternatives to thiols to stabilize metallic nanoparticles and planar surfaces. While most studies thus far have focused on NHC-functionalized gold nanoparticles (AuNPs), as an ideal platform to investigate the role of NHCs in stabilizing such nanoparticles, their ability to protect more unstable coinage metal nanoparticles, such as silver nanoparticles (AgNPs), has been largely overlooked. This is despite the fact that AgNPs possess a much more sensitive optical response that, upon their enhanced stability, can broaden their scope of application in various fields, including nanomedicine and catalysis. In this study, the synthesis and use of monomeric and polymeric mesoionic NHC-Ag(I) complexes as precursors to mono- and multidentate NHC-tethered AgNPs are reported. The polymeric analog was obtained by first synthesizing a polymer, containing 1,2,3-triazole repeat units, employing the copper-catalyzed alkyne-azide cycloaddition click polymerization of monomers containing diazide- and dialkyne functional groups. Subsequent quaternization of the triazole moieties and Ag insertion yielded the target NHC-Ag-containing polymer. Using this polymer as well as its monomeric analog as substrates, AgNPs with either catenated networks of NHCs or monomeric NHCs were fabricated by their reduction using borane-tert-butylamine complex. Our stability studies demonstrate that while monomeric NHCs impart some degree of stability to AgNPs, particularly at elevated temperatures in aqueous as well as organic medium, their polymeric analogs further enhance their stability in acidic environment (pH = 2) and against glutathione (3 mM), as an example of a biologically relevant thiol, in aqueous media. To highlight the application of these NHC-functionalized AgNPs in catalysis, we explore the aqueous phase reduction of methyl orange and 4-nitrophenol.

Synergistic Bonding of Poly(N-isopropylacrylamide)-Based Hybrid Microgels and Gold Nanoparticles Used for Temperature-Responsive Controllable Catalysis of p-Nitrophenol Reduction

Stimuli-responsive hybrid nanoparticles used for controllable catalysis have been attracting increasing attention. This study aims to prepare hybrid microgels with excellent temperature-sensitive colorimetric and catalytic properties through combining the surface plasmon resonance properties of gold nanoparticles (AuNPs) with the temperature-sensitive properties of poly(N-isopropylacrylamide) (PNIPAM)-based microgels. Microgels with hydroxy groups (MG-OH) were prepared by soap-free emulsion polymerization, using N-isopropylacrylamide as the main monomer, hydroxyethyl methylacrylate as the functional monomer, N,N'-methylene bisacrylamide as the crosslinker, and 2,2'-azobis(2-methylpropionamidine) dihydrochloride as an initiator to ensure the microgels are positively charged. Furthermore, chemical modification on the surface of MG-OH was carried out by 3-mercaptopropyltriethoxysilane to obtain thiolated microgels (MG-SH). Two kinds of hybrid nanoparticles, AuNPs@MG-OH and AuNPs@MG-SH, were self-assembled, through electrostatic interaction between positive MG-OH and negative citrate-stabilized AuNPs as well as through synergistic bonding of electrostatic interaction and Au-S bonding between positive MG-SH and negative AuNPs. The morphology, stability, temperature-sensitive colorimetric properties, and catalytic properties of hybrid microgels were systematically investigated. Results showed that although both AuNPs@MG-OH and AuNPs@MG-SH exhibit good temperature-sensitive colorimetric properties and controllable catalytic properties for the reduction reaction of p-nitrophenol, AuNPs@MG-SH with synergistic bonding has better stability and higher catalytic performance than AuNPs@MG-OH. This work has good competitiveness against known PNIPAM-based materials and may provide an effective method for preparing smart catalysts by self-assembly with stimuli-responsive polymers, which has a great potential application for catalyzing a variety of reactions.

Advances in the use of nanomaterials for nucleic acid detection in point-of-care testing devices: A review

The outbreak of the coronavirus (COVID-19) has heightened awareness of the importance of quick and easy testing. The convenience, speed, and timely results from point-of-care testing (POCT) in all vitro diagnostic devices has drawn the strong interest of researchers. However, there are still many challenges in the development of POCT devices, such as the pretreatment of samples, detection sensitivity, specificity, and so on. It is anticipated that the unique properties of nanomaterials, e.g., their magnetic, optical, thermal, and electrically conductive features, will address the deficiencies that currently exist in POCT devices. In this review, we mainly analyze the work processes of POCT devices, especially in nucleic acid detection, and summarize how novel nanomaterials used in various aspects of POCT products can improve performance, with the ultimate aims of offering new ideas for the application of nanomaterials and the overall development of POCT devices.

Biomineralized Manganese Oxide Nanoparticles Synergistically Relieve Tumor Hypoxia and Activate Immune Response with Radiotherapy in Non-Small Cell Lung Cancer

Radiotherapy (RT) is currently considered as an essential treatment for non-small cell lung cancer (NSCLC); it can induce cell death directly and indirectly via promoting systemic immune responses. However, there still exist obstacles that affect the efficacy of RT such as tumor hypoxia and immunosuppressive tumor microenvironment (TME). Herein, we report that the biomineralized manganese oxide nanoparticles (Bio-MnO₂ NPs) prepared by mild enzymatic reaction could be a promising candidate to synergistically enhance RT and RT-induced immune responses by relieving tumor hypoxia and activating cGAS-STING pathway. Bio-MnO₂ NPs could convert endogenic H₂O₂ to O₂ and catalyze the generation of reactive oxygen species so as to sensitize the radiosensitivity of NSCLC cells. Meanwhile, the release of Mn²⁺ into the TME significantly enhanced the cGAS-STING activity to activate radio-immune responses, boosting immunogenic cell death and increasing cytotoxic T cell infiltration. Collectively, this work presents the great promise of TME reversal with Bio-MnO₂ NPs to collaborate RT-induced antitumor immune responses in NSCLC.