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.

纳米酶

纳米酶(Nanozymes)是由我国科学家首次提出的新概念,它是一类具有生物催化功能的纳米材料,能够基于特定的纳米结构催化天然酶的底物并作为酶的代替品。自2007年首次报道以来,全球已有来自于55个国家的420多个研究机构证实了纳米酶的普遍规律。纳米酶的发现第一次揭示纳米材料蕴含一种独特的纳米效应———类酶催化效应。纳米酶作为一种新材料,既有纳米材料本身的理化性质,又有类似酶的催化功能,兼具天然酶与人工酶的优势于一身。其中,纳米结构不仅赋予纳米酶高效催化功能,而且使纳米酶比天然酶稳定,易于规模化生产。另外,纳米酶独特的多酶活性将为设计廉价、稳定、各种各样全新的催化级联反应提供功能分子。纳米酶是多学科交叉融合的典范,2022年被IUPAC评为十大化学新兴技术。在全球从事化学、酶学、材料学、生物学、医学、理论计算等多领域科学家的共同推进下,如今纳米酶已经成为新的研究热点。我国科学家在这一新兴领域一直发挥着引领作用,解析了纳米酶的构⁃效关系,将其催化活性提高了约1万倍,实现了超越天然酶的理性设计,创造了全球首个纳米酶产品,出版了纳米酶学英文专著,发布纳米酶术语及中国/国际标准化。更可喜的是,纳米酶新领域汇集了一大批多学科交叉融合的优秀青年科学家,推动纳米酶进入高速发展阶段,纳米酶的种类已经超过1200多种,其催化机制研究也更加深入,应用研究也从当初的检测逐步拓展到纳米酶催化医学、传感检测、绿色合成、新能源、环境治理等多个领域。本文向读者介绍纳米酶自发现以来的主要进展,包括最近发现的天然纳米酶,期待纳米酶从新概念、新材料衍生出新技术、新产品、新商品,服务人类健康,并带动新学科发展。

Metastable Iron Sulfides: A Versatile Antibacterial Candidate with Multiple Mechanisms against Bacterial Resistance

Bacterial infections pose an ongoing threat to global human health,an issue of growing urgency due to the emergence of resistance against many currently available antibiotics.Recently,the World Health Organization(WHO)launched a global appeal for the development of novel antibiotics to combat this issue.Ideal antibiotics should possess specific antibacterial effects,without causing resistance.However,the discovery of different antibiotics is lagging the development of drug-resistant bacteria.Many newly developed antibiotics not only are rapidly resisted by bacteria but also are ineffective against persistent bacteria embedded in biofilms and host cells.To tackle these challenges,innovative concepts and approaches are required for the discovery of novel antibacterial candidates.Agents for use against pathogenic bacteria were developed long before the discovery of antibiotics.For 3000 years,garlic has been considered an efficient antibacterial compound,utilized to prevent and treat bacterial infection worldwide,although the specific mechanisms remain unclear.Modern research shows that sulfur-containing chemicals are the primary active constituents of garlic and play key roles in its inherent antimicrobial activity,such as diallyl disulfide(DADS)and diallyl trisulfide(DATS).In contrast,inorganic sulfides for antibacterial use have not been deeply studied.It has been well-known that iron sulfides are an essential part of the geochemical and biological sulfur cycles.Both stable and metastable iron sulfides can be formed under abiotic sediment conditions and biotic process.In particular,certain bacteria species growth need iron sulfide as nutrient source or produce iron sulfide.In addition,iron sulfur clusters as special metastable iron sulfide take part in many important metabolic pathways in most organisms.These physicochemical and biological properties inspire us that iron sulfides are a type of valuable material for investigation and utilization.Below we will introduce a new antibacterial candidate based on iron sulfides,which kill bacteria via multiple mechanisms of action(MoAs).We will first discuss the types of iron sulfides with inherent antibacterial activity,i.e.,metastable species that can release iron ions and polysulfides in aqua.The intrinsic properties of iron sulfides and released iron and polysulfides are analyzed in regard to antibacterial effects under different physiological conditions.In particular,ferrous ion−polysulfide synergized ferroptosis-like death is proposed to kill bacteria with broad spectrum and selectivity.In addition,the versatile MoAs enable metastable iron sulfides(mFeSs)to kill resistant bacteria,eradicate biofilms,and suppress intracellular persistent species without causing new drug resistance.Importantly,the efficient antibacterial properties have been validated in animal models bearing infections including wounds,pneumonia,caries,and bacterial vaginosis,demonstrating great translational potential.Lastly,we will summarize the challenges of iron sulfides,proposing a possible development direction in the future.Our studies on iron sulfides can serve as a paradigm for the design and discovery of antibacterial nanomaterials,which may contribute for the war against drug-resistant pathogenic bacteria.

纳米酶:新一代人工酶

纳米酶是中国科学家提出的新概念,已经被纳入教科书和百科全书.汪尔康院士团队最先将纳米酶用于分析检测,并在国际权威期刊发表长篇综述“纳米酶:新一代人工酶”.该文不仅提升了纳米酶的国际影响力,而且推动了纳米酶的应用研究,使纳米酶新品种、新技术和新产品不断涌现,形成了纳米酶新型交叉学科.在此基础上,本文概述了纳米酶的定义、分类和催化机制,介绍了其应用研究的最新进展,并对其未来的研究方向和发展趋势进行了展望.

Nanozymes： an emerging field bridging nanotechnology and biology

Enzymes are biological catalysts that can convert substrates into products in biochemical reactions.In 1926,the first enzyme,urease,was determined to be a protein by James B.Sumner who won the Nobel Prize in 1946.Since then,enzymes have been considered to be proteins,which allows them to achieve their high catalytic activity with high specific activity under mild conditions.However,in general,the enzyme activity of proteins is lost after exposure to extremes of p H and high temperature,and proteins are also susceptible to digestion by proteases in the environment,which dramatically hinders their practical applications

Vitamin B2 functionalized iron oxide nanozymes for mouth ulcer healing

Mouth ulcer is associated with inflammation and high risk of bacterial infection, which aggravates the patient's condition.Currently, there is no effective treatment for mouth ulcer. Herein, we report that vitamin-modified iron oxide nanoparticles improve the healing of mouth ulcer through anti-inflammation and antibacterial activities. We discovered that vitamin B2(VB2)modified iron oxide nanoparticles performed enhanced peroxidase-like, catalase-like, and superoxide dismutase(SOD)-like activities, acting as typical iron oxide nanozymes(IONzymes) with triad activities. In particular, VB2 modification significantly improved the SOD-like activity, thus providing a reactive oxygen species(ROS)-scavenging ability. Cellular antioxidant experiments showed that vitamin B2 modified IONzymes(VB2-IONzymes) protect human oral keratinocytes(HOK) and BALB/3 T3 cells from hydrogen peroxide(H2O2), and these cells have high biocompatibility to eukaryotic cells. In addition, VB2-IONzymes exerted an antibacterial activity against Streptococcus mutans, Staphylococcus aureus, and Escherichia coli. Importantly, VB2-IONzymes accelerated the recovery of mouth ulcer and reduced the local secretion of inflammatory factors in mouse ulcer model via ROS scavenging and antibacterial activity. Taken together, our work demonstrates that vitamin B2 modification endows iron oxide nanoparticles with enhanced enzyme-like activities and VB2-IONzymes may be a promising reagent in the treatment of mouth ulcer because of their intrinsic anti-inflammation and antibacterial capabilities.

较人参皂苷Rg3生物高效的新型制剂-竹节参片研究（英文）

本文制备竹节参片并进行生物等效性考察。采用超微粉碎-湿法造粒制备竹节参片;按药典规定进行质量检查;高效液相色谱法测定自制竹节参片和人参皂苷Rg3单剂量灌胃后24小时大鼠的血药浓度, DAS 2.0软件计算分析其药动学参数和相对生物利用度。结果发现,自制竹节参片质量检查各项符合2015版药典要求,与人参皂苷Rg3相比具有较高的生物利用度。因此可知,本实验竹节参片制备工艺合理、质量可控,口服吸收利用度好,为竹节参片的工业化生产和临床应用提供参考。