Highly sensitive nanozyme strip:An effective tool for forensic material evidence identification

During criminal case investigations,blood evidence tracing is critical for criminal investigation.However,the blood stains are often cleaned or covered up after the crime,resulting in trace residue and difficult tracking.Therefore,a highly sensitive and specific method for the rapid detection of human blood stains remains urgent.To solve this problem,we established a nanozyme-based strip for rapid detection of blood evidence with high sensitivity and specificity.To construct reliable nanozyme strips,we synthesized CoFe_(2)O_(4) nanozymes with high peroxidase-like activity by scaling up to gram level,which can be supplied for six million tests,and conjugated antibody as a detection probe in nanozyme strip.The developed CoFe_(2)O_(4) nanozyme strip can detect human hemoglobin(HGB)at a concentration as low as 1 ng/mL,which is 100 times lower than the commercially available colloidal gold strips(100 ng/mL).Moreover,this CoFe_(2)O_(4) nanozyme strip showed high generality on 12 substrates and high specificity to human HGB among 13 animal blood samples.Finally,we applied the developed CoFe_(2)O_(4) nanozyme strip to successfully detect blood stains in three real cases,where the current commercial colloidal gold strip failed to do.The results suggest that the CoFe_(2)O_(4) nanozyme strip can be used as an effective on-scene detection method for human blood stains,and can further be used as a long-term preserved material evidence for traceability inquiry.

Multiscale structural design of MnO_(2)@GO superoxide dismutase nanozyme for protection against antioxidant damage

Rational design of metallic active sites and its microenvironment is critical for constructing superoxide dismutase(SOD)nanozymes.Here,we reported a novel SOD nanozyme design,with employing graphene oxide(GO)as the framework,andδ-MnO_(2)as the active sites,to mimic the natural Mn-SOD.This MnO_(2)@GO nanozyme exhibited multiscale laminated structures with honeycomb-like morphology,providing highly specific surface area for·O_(2)−adsorption and confined spaces for subsequent catalytic reactions.Thus,the nanozyme achieved superlative SOD-like catalytic performance with inhibition rate of 95.5%,which is 222.6%and 1605.4%amplification over GO and MnO_(2)nanoparticles,respectively.Additionally,such unique hierarchical structural design endows MnO_(2)@GO with catalytic specificity,which was not present in the individual component(GO or MnO_(2)).This multiscale structural design provides new strategies for developing highly active and specific SOD nanozymes.

HBV precore G1896A mutation promotes growth of hepatocellular carcinoma cells by activating ERK/MAPK pathway

Chronic hepatitis B virus(HBV)infection is one of the leading causes of hepatocellular carcinoma(HCC).The HBV genome is prone to mutate and several variants are closely related to the malignant transformation of liver disease.G1896A mutation(G to A mutation at nucleotide 1896)is one of the most frequently observed mutations in the precore region of HBV,which prevents HBeAg expression and is strongly associated with HCC.However,the mechanisms by which this mutation causes HCC are unclear.Here,we explored the function and molecular mechanisms of the G1896A mutation during HBV-associated HCC.G1896A mutation remarkably enhanced the HBV replication in vitro.Moreover,it increased tumor formation and inhibited apoptosis of hepatoma cells,and decreased the sensitivity of HCC to sorafenib.Mechanistically,the G1896A mutation could activate ERK/MAPK pathway to enhanced sorafenib resistance in HCC cells and augmented cell survival and growth.Collectively,our study demonstrates for the first time that the G1896A mutation has a dual regulatory role in exacerbating HCC severity and sheds some light on the treatment of G1896A mutation-associated HCC patients.

Recent progress in single-atom nanozymes research

Single-atom nanozyme(SAzyme)is the hot topic of the current nanozyme research.Its intrinsic properties,such as high activity,stability,and low cost,present great substitutes to natural enzymes.Moreover,its fundamental characteristics,i.e.,maximized atom utilizations and well-defined geometric and electronic structures,lead to higher catalytic activities and specificity than traditional nanozymes.SAzymes have been applied in many biomedical areas,such as anti-tumor therapy,biosensing,antibiosis,and anti-oxidation therapy.Here,we will discuss a series of representative examples of SAzymes categorized by their biomedical applications in this review.In the end,we will address the future opportunities and challenges SAzymes facing in their designs and applications.

A functional hydrogenase mimic that catalyzes robust H_(2) evolution spontaneously in aqueous environment

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.