Nanozymes,a type of nanomaterials with enzyme-like activity,have shown great potential to replace natural enzymes in many fields such as biochemical detection,environmental management and disease treatment.However,the...Nanozymes,a type of nanomaterials with enzyme-like activity,have shown great potential to replace natural enzymes in many fields such as biochemical detection,environmental management and disease treatment.However,the catalytic efficiency and substrate specificity of nanozymes still need improvement.To further optimize the enzymatic properties of nanozymes,recent studies have introduced the structural characteristics of natural enzymes into the rational design of nanozymes,either by employing small molecules to mimic the cofactors of natural enzymes to boost nanozymes’catalytic potential,or by simulating the active center of natural enzymes to construct the nanostructure of nanozymes.This review introduces the commonly used bio-inspired strategies to create nanozymes,aiming at clarifying the current progress and bottlenecks.Advances and challenges focusing on the research of bio-inspired nanozymes are outlined to provide ideas for the de novo design of ideal nanozymes.展开更多
Adhesive hydrogels have broad applications ranging from tissue engineering to bioelectronics;however,fabricating adhesive hydrogels with multiple functions remains a challenge.In this study,a mussel-inspired tannic ac...Adhesive hydrogels have broad applications ranging from tissue engineering to bioelectronics;however,fabricating adhesive hydrogels with multiple functions remains a challenge.In this study,a mussel-inspired tannic acid chelated-Ag(TA-Ag)nanozyme with peroxidase(POD)-like activity was designed by the in situ reduction of ultrasmall Ag nanoparticles(NPs)with TA.The ultrasmall TA-Ag nanozyme exhibited high catalytic activity to induce hydrogel self-setting without external aid.The nanozyme retained abundant phenolic hydroxyl groups and maintained the dynamic redox balance of phenol-quinone,providing the hydrogels with long-term and repeatable adhesiveness,similar to the adhesion of mussels.The phenolic hydroxyl groups also afforded uniform distribution of the nanozyme in the hydrogel network,thereby improving its mechanical properties and conductivity.Furthermore,the nanozyme endowed the hydrogel with antibacterial activity through synergistic effects of the reactive oxygen species generated via POD-like catalytic reactions and the intrinsic bactericidal activity of Ag.Owing to these advantages,the ultrasmall TA-Ag nanozyme-catalyzed hydrogel could be effectively used as an adhesive,antibacterial,and implantable bioelectrode to detect bio-signals,and as a wound dressing to accelerate tissue regeneration while preventing infection.Therefore,this study provides a promising approach for the fabrication of adhesive hydrogel bioelectronics with multiple functions via mussel-inspired nanozyme catalysis.展开更多
Antibacterial nanomaterials have attracted growing interest for bacterial infection therapy.However,most nanomaterials eliminate bacteria either physically or chemically,which hampers their efficacy when dealing with ...Antibacterial nanomaterials have attracted growing interest for bacterial infection therapy.However,most nanomaterials eliminate bacteria either physically or chemically,which hampers their efficacy when dealing with multidrug-resistant bacteria.To overcome this,we integrated copper sulfide(CuS)nanoparticles with active graphene oxide nanosheets(GO NSs)to synthesize a superior nanocomposite(CuS/GO NC)that acts both physically and chemically on the bacteria.CuS/GO NC was produced using a facile hydrothermal method,whereby the CuS nanoparticles grew and were uniformly dispersed on the GO NSs in situ.We found that the CuS/GO NC possesses a unique needle-like morphology that physically damages the bacterial cell membrane.CuS/GO NC also exhibits high oxidase-and peroxidase-like activity,ensuring efficient generation of the reactive oxygen species•OH from H2O2,which kills bacteria chemically.These features endow the CuS/GO NC with excellent antibacterial capabilities to kill multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus(MRSA)with only a single dose.Additionally,it was found that the CuS/GO NC accelerated the healing of infected wounds in vivo owing to its good biocompatibility as well as facilitation of cell migration and collagen secretion.This study provides a new strategy to combine the physical and chemical antibacterial modes of nanomaterials to develop more effective therapies to combat multidrug-resistant bacterial infections.展开更多
Infectious diseases pose a serious threat to global health.Although immunizations can control most viral infections,bacterial infections,particularly those caused by drug-resistant strains,continue to cause high rates...Infectious diseases pose a serious threat to global health.Although immunizations can control most viral infections,bacterial infections,particularly those caused by drug-resistant strains,continue to cause high rates of illness and death.Unfortunately,the creation of new antibiotics has come to a grinding halt in the last ten years.In response to this crisis,nanotechnology has emerged as a hopeful solution to tackle drug resistance and enhance treatment results.A large variety of biomimetic nanomaterials,termed nanozymes,have demonstrated strong antimicrobial efficacy.While the inherent toxicity of nanomaterials is a concern,recent studies have harnessed the stimuli-responsiveness of nanomaterials to enable local and/or targeted delivery to reduce the treatment side effects.Indeed,the physicochemical versatility of nanomaterials affords many degrees of freedom that enable rational design of smart or autonomous therapeutics,which cannot be achieved using conventional antibiotics.The design straddles the fields of catalysis,nanoscience,microbiology,and translational medicine.To provide an overview of this interdisciplinary landscape,this review is organized based on composition into lipid,metal,metal oxide,and non-metallic nanomaterials.Liposomes as a delivery vehicle enhance bioavailability and reduce toxicity.Metal-and metal oxide-based nanomaterials inhibit bacterial growth by mimicking natural enzymatic activities such as peroxidase(POD)and oxidase.Furthermore,carbon-,polymer-,and cell membrane-based nanomaterials are combined into a discussion on non-metallic materials.At the end of this review,potentially fruitful directions for future bioinspired nanomaterials in infectious disease treatment are included.展开更多
Bacterial infection,tissue hypoxia and inflammatory response can hinder the infected wound repair process.To mitigate the above issues,tannic acid-chelated Fe-decorated molybdenum disulfide nanosheets(MoS2@TA/Fe NSs)w...Bacterial infection,tissue hypoxia and inflammatory response can hinder the infected wound repair process.To mitigate the above issues,tannic acid-chelated Fe-decorated molybdenum disulfide nanosheets(MoS2@TA/Fe NSs)with dual enzyme activities were developed and anchored to a multifunctional hydrogel.The hydrogel exhibited excellent antibacterial ability owing to the combined effects of photothermal therapy(PTT),glutathione(GSH)loss,and the peroxidase(POD)-like activity(catalyse H2O_(2)into⋅OH under acid condition)of MoS2@TA/Fe NSs.Benefitting from the catalase(CAT)-like activity,the hydrogel could decompose H2O_(2)into O_(2)at neutral pH to relieve hypoxia and supply adequate O_(2).POD-like activity was mainly attributed to MoS2 NSs,while CAT-like activity was primarily due to TA/Fe complex.Moreover,MoS2@TA/Fe NSs endowed the hydrogel with outstanding anti-oxidant ability to scavenge redundant reactive oxygen species(ROS)and reactive nitrogen species(RNS)under neutral environment to maintain the balance of antioxidant systems and prevent inflammation.In addition,the hydrogel could inhibit the release of inflammatory factors for the anti-inflammatory property of TA.TA retained partial phenolic hydroxyl groups,which cross-linked the nanosheets to the network structure of the hydrogel and promoted the adhesion of hydrogels.Due to the dynamic boron ester bonds between polyvinyl alcohol(PVA),dextran(Dex),MoS2@TA/Fe,and borax,the hydrogel demonstrated fast self-healing and rapid shape adaptability.This shape-adaptable adhesive hydrogel could fill the whole wound and closely contact the wound,ensuring that it achieved its functions with maximum efficiency.The MoS2@TA/Fe nanozyme-anchored multifunctional hydrogel showed high potential for bacteria-infected wound healing.展开更多
Although great progress has been made in improving hydrogen production,highly efficient catalysts,which are able to produce hydrogen in a fast and steady way at ambient temperature and pressure,are still in large dema...Although great progress has been made in improving hydrogen production,highly efficient catalysts,which are able to produce hydrogen in a fast and steady way at ambient temperature and pressure,are still in large demand.Here,we report a[NiCo]-based hydrogenase mimic,NiCo_(2)O_(4) nanozyme,that can catalyze robust hydrogen evolution spontaneously in water without external energy input at room temperature.This hydrogenase nanozyme facilitates water splitting reaction by forming a three-center Ni-OH-Co bond analogous to the[NiFe]-hydrogenase reaction by using aluminum as electron donor,and realizes hydrogen evolution with a high production rate of 915 L·h^(-1) per gram of nanozymes,which is hundreds of times higher than most of the natural hydrogenase or hydrogenase mimics.Furthermore,the NiCo_(2)O_(4) nanozyme can robustly disrupt the adhesive oxidized layer of aluminum and enable the full consumption of electrons from aluminum.In contrast to the often-expensive synthetic catalysts that rely on rare elements and consume high energy,we envision that this NiCo_(2)O_(4) nanozyme can potentially provide an upgrade for current hydrogen evolution,accelerate the development of scale-up hydrogen production,and generate a clean energy future.展开更多
Parkinson’s disease(PD)is a prevalent neurodegenerative disorder accompanied by movement disorders and neuroinflammatory injury.Anti-inflammatory intervention to regulate oxidative stress in the brain is beneficial f...Parkinson’s disease(PD)is a prevalent neurodegenerative disorder accompanied by movement disorders and neuroinflammatory injury.Anti-inflammatory intervention to regulate oxidative stress in the brain is beneficial for managing PD.However,traditional natural antioxidants have failed to meet the clinical treatment demands due to insufficient activity and sustainability.Herein,Cu-doping zeolite imidazolate framework-8(ZIF-8)nanozyme is designed to simulate Cu/Zn superoxide dismutase(SOD)by biomimetic mineralization.The nanozyme composite is then integrated into thermosensitive hydrogel(poly(lactic-co-glycolic acid)-poly(ethylene glycol)-poly(lactic-co-glycolic acid)(PLGA-PEG-PLGA))to form an effective antioxidant system(Cu-ZIF@Hydrogel).The thermosensitive hydrogel incorporating nanozymes demonstrate distinct viscoelastic properties aimed at enhancing local nanozyme adhesion,prolonging nanozyme retention time,and modulating antioxidant activity,thus significantly improving the bioavailability of nanozymes.At the cellular and animal levels of PD,we find that Cu-ZIF@Hydrogel bypass the blood-brain barrier and efficiently accumulate in the nerve cells.Moreover,the Cu-ZIF@Hydrogel significantly alleviate the PD’s behavioral and pathological symptoms by reducing the neuroinflammatory levels in the lesion site.Therefore,the hydrogel-incorporating nanozyme system holds great potential as a simple and reliable avenue for managing PD.展开更多
Detection of enzyme biomarkers originating from either bio-fluids or contaminating microorganisms is of utmost importance in clinical diagnostics and food safety. Herein, we present a simple, low-cost and easy-to-use ...Detection of enzyme biomarkers originating from either bio-fluids or contaminating microorganisms is of utmost importance in clinical diagnostics and food safety. Herein, we present a simple, low-cost and easy-to-use sensing approach based on the switchable peroxidase-mimicking activity of plasmonic gold nanoparticles (AuNPs) that can catalyse for the oxidation of 3,3’,5’5-tetramethylbenzidine (TMB) for the determination of protease enzyme. The AuNP surface is modified with casein, showing dual functionalities. The first function of the coating molecule is to suppress the intrinsic peroxidase-mimicking activity of AuNPs by up to 77.1%, due to surface shielding effects. Secondly, casein also functions as recognition sites for the enzyme biomarker. In the presence of protease, the enzyme binds to and catalyses the degradation of the coating layer on the AuNP surface, resulting in the recovery of peroxidase-mimicking activity. This is shown visually in the development of a blue colored product (oxidised TMB) or spectroscopically as an increase in absorbance at 370 and 650 nm. This mechanism allows for the detection of protease at 44 ng·mL^-1 in 90 min. The nanosensor circumvents issues associated with current methods of detection in terms of ease of use, compatibility with point-of-care testing, low-cost production and short analysis time. The sensing approach has also been applied for the detection of protease spiked in ultra-heat treated (UHT) milk and synthetic human urine samples at a limit of detection of 490 and 176 ng·mL^-1, respectively, showing great potential in clinical diagnostics, food safety and quality control.展开更多
基金financially supported by the National Natural Science Foundation of China(31871005,31530026,and 31900981)Chinese Academy of Sciences(YJKYYQ20180048),the Strategic Priority Research Program(XDB29040101)+2 种基金the Key Research Program of Frontier Sciences(QYZDY-SSW-SMC013)Chinese Academy of Sciences and National Key Research and Development Program of China(2017YFA0205501)Youth Innovation Promotion Association CAS(2019093)。
文摘Nanozymes,a type of nanomaterials with enzyme-like activity,have shown great potential to replace natural enzymes in many fields such as biochemical detection,environmental management and disease treatment.However,the catalytic efficiency and substrate specificity of nanozymes still need improvement.To further optimize the enzymatic properties of nanozymes,recent studies have introduced the structural characteristics of natural enzymes into the rational design of nanozymes,either by employing small molecules to mimic the cofactors of natural enzymes to boost nanozymes’catalytic potential,or by simulating the active center of natural enzymes to construct the nanostructure of nanozymes.This review introduces the commonly used bio-inspired strategies to create nanozymes,aiming at clarifying the current progress and bottlenecks.Advances and challenges focusing on the research of bio-inspired nanozymes are outlined to provide ideas for the de novo design of ideal nanozymes.
基金This work was financially supported by the National Key Research and Development Program of China(2016YFB0700800)Key-Area Research and Development Program of Guang Dong Province(2019B010941002)+3 种基金NSFC(82072071,82072073)Fundamental Research Funds for the Central Universities(2682020ZT79)Sichuan Science and Technology Program(2020YJ0009)Young Scientific and Technological Innovation Research Team Funds of Sichuan Province(20CXTD0106).
文摘Adhesive hydrogels have broad applications ranging from tissue engineering to bioelectronics;however,fabricating adhesive hydrogels with multiple functions remains a challenge.In this study,a mussel-inspired tannic acid chelated-Ag(TA-Ag)nanozyme with peroxidase(POD)-like activity was designed by the in situ reduction of ultrasmall Ag nanoparticles(NPs)with TA.The ultrasmall TA-Ag nanozyme exhibited high catalytic activity to induce hydrogel self-setting without external aid.The nanozyme retained abundant phenolic hydroxyl groups and maintained the dynamic redox balance of phenol-quinone,providing the hydrogels with long-term and repeatable adhesiveness,similar to the adhesion of mussels.The phenolic hydroxyl groups also afforded uniform distribution of the nanozyme in the hydrogel network,thereby improving its mechanical properties and conductivity.Furthermore,the nanozyme endowed the hydrogel with antibacterial activity through synergistic effects of the reactive oxygen species generated via POD-like catalytic reactions and the intrinsic bactericidal activity of Ag.Owing to these advantages,the ultrasmall TA-Ag nanozyme-catalyzed hydrogel could be effectively used as an adhesive,antibacterial,and implantable bioelectrode to detect bio-signals,and as a wound dressing to accelerate tissue regeneration while preventing infection.Therefore,this study provides a promising approach for the fabrication of adhesive hydrogel bioelectronics with multiple functions via mussel-inspired nanozyme catalysis.
基金This study was supported by the National Natural Science Foundation of China(Nos.81972080 and 81902198)China Postdoctoral Science Foundation(Nos.2018M640776,2019M662980,and BX20190150)+5 种基金Natural Science Foundation of Guangdong Province(Nos.2015A30312004 and 2020A1515010398)Science and Technology Planning Project of Guangdong Province(Nos.2014A020215025 and 2017B030314139)Medical Research Foundation of Guangdong Province(A2019228)Research Program of PLA(No.CGZ16C004)President Foundation of Zhujiang Hospital,Southern Medical University(No.yzjj2018rc09)Scientific Research Foundation of Southern Medical University(Nos.C1051353 and PY2018N060).
文摘Antibacterial nanomaterials have attracted growing interest for bacterial infection therapy.However,most nanomaterials eliminate bacteria either physically or chemically,which hampers their efficacy when dealing with multidrug-resistant bacteria.To overcome this,we integrated copper sulfide(CuS)nanoparticles with active graphene oxide nanosheets(GO NSs)to synthesize a superior nanocomposite(CuS/GO NC)that acts both physically and chemically on the bacteria.CuS/GO NC was produced using a facile hydrothermal method,whereby the CuS nanoparticles grew and were uniformly dispersed on the GO NSs in situ.We found that the CuS/GO NC possesses a unique needle-like morphology that physically damages the bacterial cell membrane.CuS/GO NC also exhibits high oxidase-and peroxidase-like activity,ensuring efficient generation of the reactive oxygen species•OH from H2O2,which kills bacteria chemically.These features endow the CuS/GO NC with excellent antibacterial capabilities to kill multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus(MRSA)with only a single dose.Additionally,it was found that the CuS/GO NC accelerated the healing of infected wounds in vivo owing to its good biocompatibility as well as facilitation of cell migration and collagen secretion.This study provides a new strategy to combine the physical and chemical antibacterial modes of nanomaterials to develop more effective therapies to combat multidrug-resistant bacterial infections.
基金supported by the Department of Defense,Office of Naval Research(ONR award N00014-20-1-2418)National Institutes of Health,National Institute on Deafness and Other Communication Disorders(NIHDC016644).
文摘Infectious diseases pose a serious threat to global health.Although immunizations can control most viral infections,bacterial infections,particularly those caused by drug-resistant strains,continue to cause high rates of illness and death.Unfortunately,the creation of new antibiotics has come to a grinding halt in the last ten years.In response to this crisis,nanotechnology has emerged as a hopeful solution to tackle drug resistance and enhance treatment results.A large variety of biomimetic nanomaterials,termed nanozymes,have demonstrated strong antimicrobial efficacy.While the inherent toxicity of nanomaterials is a concern,recent studies have harnessed the stimuli-responsiveness of nanomaterials to enable local and/or targeted delivery to reduce the treatment side effects.Indeed,the physicochemical versatility of nanomaterials affords many degrees of freedom that enable rational design of smart or autonomous therapeutics,which cannot be achieved using conventional antibiotics.The design straddles the fields of catalysis,nanoscience,microbiology,and translational medicine.To provide an overview of this interdisciplinary landscape,this review is organized based on composition into lipid,metal,metal oxide,and non-metallic nanomaterials.Liposomes as a delivery vehicle enhance bioavailability and reduce toxicity.Metal-and metal oxide-based nanomaterials inhibit bacterial growth by mimicking natural enzymatic activities such as peroxidase(POD)and oxidase.Furthermore,carbon-,polymer-,and cell membrane-based nanomaterials are combined into a discussion on non-metallic materials.At the end of this review,potentially fruitful directions for future bioinspired nanomaterials in infectious disease treatment are included.
基金This work was supported by the National Natural Science Foundation of China(grant numbers 21878247)Key Program of the National Natural Science Foundation of China(grant numbers 21838009)+2 种基金National Key Research and Development Program(2019YFA0905200)and Xi’an Science and Technology Project(20191422315KYPT014JC016)The authors thank Dr.J.C.Li(School of Chemical Engineering,Northwest University,Xi’an,China)for improving the manuscript during revising.
文摘Bacterial infection,tissue hypoxia and inflammatory response can hinder the infected wound repair process.To mitigate the above issues,tannic acid-chelated Fe-decorated molybdenum disulfide nanosheets(MoS2@TA/Fe NSs)with dual enzyme activities were developed and anchored to a multifunctional hydrogel.The hydrogel exhibited excellent antibacterial ability owing to the combined effects of photothermal therapy(PTT),glutathione(GSH)loss,and the peroxidase(POD)-like activity(catalyse H2O_(2)into⋅OH under acid condition)of MoS2@TA/Fe NSs.Benefitting from the catalase(CAT)-like activity,the hydrogel could decompose H2O_(2)into O_(2)at neutral pH to relieve hypoxia and supply adequate O_(2).POD-like activity was mainly attributed to MoS2 NSs,while CAT-like activity was primarily due to TA/Fe complex.Moreover,MoS2@TA/Fe NSs endowed the hydrogel with outstanding anti-oxidant ability to scavenge redundant reactive oxygen species(ROS)and reactive nitrogen species(RNS)under neutral environment to maintain the balance of antioxidant systems and prevent inflammation.In addition,the hydrogel could inhibit the release of inflammatory factors for the anti-inflammatory property of TA.TA retained partial phenolic hydroxyl groups,which cross-linked the nanosheets to the network structure of the hydrogel and promoted the adhesion of hydrogels.Due to the dynamic boron ester bonds between polyvinyl alcohol(PVA),dextran(Dex),MoS2@TA/Fe,and borax,the hydrogel demonstrated fast self-healing and rapid shape adaptability.This shape-adaptable adhesive hydrogel could fill the whole wound and closely contact the wound,ensuring that it achieved its functions with maximum efficiency.The MoS2@TA/Fe nanozyme-anchored multifunctional hydrogel showed high potential for bacteria-infected wound healing.
基金supported by the National Natural Science Foundation of China(Nos.T2225026,82172087,22025604,82071308,52202344)the National Key R&D Program of China(No.2022YFA120012501)Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘Although great progress has been made in improving hydrogen production,highly efficient catalysts,which are able to produce hydrogen in a fast and steady way at ambient temperature and pressure,are still in large demand.Here,we report a[NiCo]-based hydrogenase mimic,NiCo_(2)O_(4) nanozyme,that can catalyze robust hydrogen evolution spontaneously in water without external energy input at room temperature.This hydrogenase nanozyme facilitates water splitting reaction by forming a three-center Ni-OH-Co bond analogous to the[NiFe]-hydrogenase reaction by using aluminum as electron donor,and realizes hydrogen evolution with a high production rate of 915 L·h^(-1) per gram of nanozymes,which is hundreds of times higher than most of the natural hydrogenase or hydrogenase mimics.Furthermore,the NiCo_(2)O_(4) nanozyme can robustly disrupt the adhesive oxidized layer of aluminum and enable the full consumption of electrons from aluminum.In contrast to the often-expensive synthetic catalysts that rely on rare elements and consume high energy,we envision that this NiCo_(2)O_(4) nanozyme can potentially provide an upgrade for current hydrogen evolution,accelerate the development of scale-up hydrogen production,and generate a clean energy future.
基金support by the CAS Interdisciplinary Innovation Team(No.JCTD-2020-08).
文摘Parkinson’s disease(PD)is a prevalent neurodegenerative disorder accompanied by movement disorders and neuroinflammatory injury.Anti-inflammatory intervention to regulate oxidative stress in the brain is beneficial for managing PD.However,traditional natural antioxidants have failed to meet the clinical treatment demands due to insufficient activity and sustainability.Herein,Cu-doping zeolite imidazolate framework-8(ZIF-8)nanozyme is designed to simulate Cu/Zn superoxide dismutase(SOD)by biomimetic mineralization.The nanozyme composite is then integrated into thermosensitive hydrogel(poly(lactic-co-glycolic acid)-poly(ethylene glycol)-poly(lactic-co-glycolic acid)(PLGA-PEG-PLGA))to form an effective antioxidant system(Cu-ZIF@Hydrogel).The thermosensitive hydrogel incorporating nanozymes demonstrate distinct viscoelastic properties aimed at enhancing local nanozyme adhesion,prolonging nanozyme retention time,and modulating antioxidant activity,thus significantly improving the bioavailability of nanozymes.At the cellular and animal levels of PD,we find that Cu-ZIF@Hydrogel bypass the blood-brain barrier and efficiently accumulate in the nerve cells.Moreover,the Cu-ZIF@Hydrogel significantly alleviate the PD’s behavioral and pathological symptoms by reducing the neuroinflammatory levels in the lesion site.Therefore,the hydrogel-incorporating nanozyme system holds great potential as a simple and reliable avenue for managing PD.
文摘Detection of enzyme biomarkers originating from either bio-fluids or contaminating microorganisms is of utmost importance in clinical diagnostics and food safety. Herein, we present a simple, low-cost and easy-to-use sensing approach based on the switchable peroxidase-mimicking activity of plasmonic gold nanoparticles (AuNPs) that can catalyse for the oxidation of 3,3’,5’5-tetramethylbenzidine (TMB) for the determination of protease enzyme. The AuNP surface is modified with casein, showing dual functionalities. The first function of the coating molecule is to suppress the intrinsic peroxidase-mimicking activity of AuNPs by up to 77.1%, due to surface shielding effects. Secondly, casein also functions as recognition sites for the enzyme biomarker. In the presence of protease, the enzyme binds to and catalyses the degradation of the coating layer on the AuNP surface, resulting in the recovery of peroxidase-mimicking activity. This is shown visually in the development of a blue colored product (oxidised TMB) or spectroscopically as an increase in absorbance at 370 and 650 nm. This mechanism allows for the detection of protease at 44 ng·mL^-1 in 90 min. The nanosensor circumvents issues associated with current methods of detection in terms of ease of use, compatibility with point-of-care testing, low-cost production and short analysis time. The sensing approach has also been applied for the detection of protease spiked in ultra-heat treated (UHT) milk and synthetic human urine samples at a limit of detection of 490 and 176 ng·mL^-1, respectively, showing great potential in clinical diagnostics, food safety and quality control.
