Separation of chitin from shrimp shells enabled by transition metal salt aqueous solution and ionic liquid

Chitin is a widely used important industrial polymer mainly from shrimp shells, but its commercial preparation is under the great challenge of serious pollution due to the requirement of HCl and Na OH.Herein, we demonstrated that high purity chitin can be obtained from waste shrimp shells(WSSs) by cascade separation with transition metal salt aqueous solution and ionic liquid(IL). Firstly, calcium carbonate of WSSs was effectively removed in the metal salt aqueous solution driven by the ion exchange interaction. Subsequently, 1-butyl-3-methylimidazolium chloride([Bmim]Cl) had bifunctional abilities to remove residual protein and introduced metal salts simultaneously by hydrogen bonding and coordination interactions. The key experimental factors affecting the separation process were systematically studied, including the type of metal salts, temperature, and [Bmim]Cl loading. After sequential treatment with a 20%(mass) Ni SO4aqueous solution at 130 ℃ and [Bmim]Cl at 150 ℃, the purity of a-chitin can be up to 96.5%(mass) that meets commercial requirements. The use of metal salts with higher coordination ability makes the preparation of chitin no longer depend on the commonly acid-base reaction, which is conducive to the preservation of chitin structure.

Ionizable drug delivery systems for efficient and selective gene therapy

Gene therapy has shown great potential to treat various diseases by repairing the abnormal gene function.However,a great challenge in bringing the nucleic acid formulations to the market is the safe and effective delivery to the specific tissues and cells.To be excited,the development of ionizable drug delivery systems(IDDSs)has promoted a great breakthrough as evidenced by the approval of the BNT162b2 vaccine for prevention of coronavirus disease 2019(COVID-19)in 2021.Compared with conventional cationic gene vectors,IDDSs can decrease the toxicity of carriers to cell membranes,and increase cellular uptake and endosomal escape of nucleic acids by their unique pH-responsive structures.Despite the progress,there remain necessary requirements for designing more efficient IDDSs for precise gene therapy.Herein,we systematically classify the IDDSs and summarize the characteristics and advantages of IDDSs in order to explore the underlying design mechanisms.The delivery mechanisms and therapeutic applications of IDDSs are comprehensively reviewed for the delivery of plasmid DNA(pDNA)and four kinds of RNA.In particular,organ selecting considerations and high-throughput screening are highlighted to explore efficiently multifunctional ionizable nanomaterials with superior gene delivery capacity.We anticipate providing references for researchers to rationally design more efficient and accurate targeted gene delivery systems in the future,and indicate ideas for developing next generation gene vectors.

Lignin derived absorbent for efficient and sustainable CO_(2) capture

High and cost-efficient capture of CO_(2) is a prerequisite and an inevitable path of carbon emission reduction. To address the challenges(high cost, low efficiency, less sustainability, etc.) of existing petroleum-based CO_(2) absorbents, herein, a class of efficient and sustainable lignin-based absorbents were resoundingly prepared by grafting the active amine group on a lignin derived compound vanillin and alkali lignin. The results demonstrated that vanillin modified by acrylamide achieved the excellent absorption capacity among the three absorbents, whose ability was 0.114 g CO_(2) per gram of absorbent under 25 ℃ and 100 kPa. In addition, the absorbent retained stable absorbability of CO_(2) after 6 cycles.The absorbing capacity of the absorbent formed by the coupling of vanillin and acrylamide to CO_(2) was much greater than their own(i.e. 0 g CO_(2) ·g^(-1)vanillin, 0.01 g CO_(2) ·g^(-1) acrylamide, respectively).Detailed information revealed the multi-site synergistic absorption mechanism, in which CO_(2) has C and O double interactions with the amide group of the absorbent, and single interaction with the hydroxyl oxygen on the benzene ring of the absorbent. The absorption capacity of modified lignin for CO_(2) is as high as 0.12 g CO_(2) per gram of absorbent, which is comparable with that of model compound vanillin.This work not only provides a new idea for the design of bio-absorbents for CO_(2) capture, but explores the application potential of lignin-based materials.

Advances of nanoparticles as drug delivery systems for disease diagnosis and treatment

Decades have passed since the first nanoparticles-base medicine was approved for human cancer treatment, and the research and development of nanoparticles for drug delivery are always undergoing.Nowadays, the significant advances complicate nanoparticles’ branches, including liposomes, solid lipid nanoparticles, inorganic nanoparticles, micelles, nanovaccines and nano-antibodies, etc. These nanoparticles show numerous capabilities in treatment and diagnosis of stubborn diseases like cancer and neurodegenerative diseases, emerging as novel drug carriers or therapeutic agents in future. In this review, the complicated branches of nanoparticles are classified and summarized, with their property and functions concluded. Besides, there are also some delivery strategies that make nanoparticles smarter and more efficient in drug delivery, and frontiers in these strategies are also summarized in this review. Except these excellent works in newly-produced drug delivery nanoparticles, some points of view and future expectations are made in the end.

Antitumor synergism between PAK4 silencing and immunogenic phototherapy of engineered extracellular vesicles

Immunotherapy has revolutionized the landscape of cancer treatment.However,single immunotherapy only works well in a small subset of patients.Combined immunotherapy with antitumor synergism holds considerable potential to boost the therapeutic outcome.Nevertheless,the synergistic,additive or antagonistic antitumor effects of combined immunotherapies have been rarely explored.Herein,we established a novel combined cancer treatment modality by synergizing p21-activated kinase 4(PAK4)silencing with immunogenic phototherapy in engineered extracellular vesicles(EVs)that were fabricated by coating M1 macrophage-derived EVs on the surface of the nano-complex cores assembled with si RNA against PAK4 and a photoactivatable polyethyleneimine.The engineered EVs induced potent PAK4 silencing and robust immunogenic phototherapy,thus contributing to effective antitumor effects in vitro and in vivo.Moreover,the antitumor synergism of the combined treatment was quantitatively determined by the Compu Syn method.The combination index(CI)and isobologram results confirmed that there was an antitumor synergism for the combined treatment.Furthermore,the dose reduction index(DRI)showed favorable dose reduction,revealing lower toxicity and higher biocompatibility of the engineered EVs.Collectively,the study presents a synergistically potentiated cancer treatment modality by combining PAK4 silencing with immunogenic phototherapy in engineered EVs,which is promising for boosting the therapeutic outcome of cancer immunotherapy.

Applications of protein engineering in the microbial synthesis of plant triterpenoids

Triterpenoids are a class of natural products widely used in fields related to medicine and health due to their biological activities such as hepatoprotection,anti-inflammation,anti-viral,and anti-tumor.With the advancement in biotechnology,microorganisms have been used as cell factories to produce diverse natural products.Despite the significant progress that has been made in the construction of microbial cell factories for the heterogeneous biosynthesis of triterpenoids,the industrial production of triterpenoids employing microorganisms has been stymied due to the shortage of efficient enzymes as well as the low expression and low catalytic activity of heterologous proteins in microbes.Protein engineering has been demonstrated as an effective way for improving the specificity,catalytic activity,and stability of the enzyme,which can be employed to overcome these challenges.This review summarizes the current progress in the studies of Oxidosqualene cyclases(OSCs),cytochrome P450s(P450s),and UDP-glycosyltransferases(UGTs),the key enzymes in the triterpenoids synthetic pathway.The main obstacles restricting the efficient catalysis of these key enzymes are analyzed,the applications of protein engineering for the three key enzymes in the microbial synthesis of triterpenoids are systematically reviewed,and the challenges and prospects of protein engineering are also discussed.

Silicon dioxide-protection boosting the peroxidase-like activity of Fe single-atom catalyst for combining chemo-photothermal therapy

Carbon-based single-atom catalysts(SACs)have been widely studied in the field of biomedicine due to their excellent catalytic performance.However,carbon-based SACs usually aggregate during pyrolysis,which leads to the reduction of catalytic activity.Here,we describe a method to improve the monodispersion of SACs using silicon dioxide as a protective layer.The decoration of silicon dioxide serves as a buffer layer for individual nanoparticles,which is not destroyed during the pyrolysis process,ensuring the single-particle dispersion of the nanoparticles after etching.This approach increased the hydroxyl groups on the surface of Fe-SAC(Fe-SAC-SE)and improved its water solubility,resulting in a four times enhancement of the peroxidase(POD)-like activity of Fe-SAC-SE(58.4 U/mg)than that of non-protected SACs(13.9 U/mg).The SiO_(2)-protection approach could also improve the catalytic activities of SACs with other metals such as Mn,Co,Ni,and Cu,indicating its generality for SACs preparation.Taking advantage of the high POD-like activity,photothermal properties,and large specific surface area of Fe-SAC-SE,we constructed a synergistic therapeutic system(Fe-SAC-SE@DOX@PEG)for combining the photothermal therapy,catalytic therapy,and chemotherapy.It was verified that the photothermal properties of Fe-SAC-SE@DOX@PEG could effectively improve its POD-like activity,exhibiting excellent tumor-killing performance at the cellular level.This work may provide a general approach to improve the performances of SACs for disease therapy and diagnosis.

Recent progresses of exosome-liposome fusions in drug delivery

Exosomes are membrane-bound nanoscale extracellular vesicles,which produced by almost all organisms.Due to the excellent biocompatibility,long circulation time as well as low immunogenicity,exosomes as naturally-derived drug delivery carriers have experienced explosive growth over the past decades.However,issues such as insufficient loading efficiency,heterogeneous delivery efficiency,uncontrollable targeting ability,and low production limit their wide application.Recently,the emerging exosome-liposome fusion strategy has become a potential approach to solve such issues.Thus,this review mainly focuses on the currently developed exosome-liposome fusion strategy and their application in drug delivery as well as disease treatment.This review aims to shed light on the advantages of fusion strategy in drug delivery and provides a better understanding for more rational design.The current challenge and future perspective regarding their clinical translation and application will also be discussed.

Metal-based inorganic nanocrystals for biological sonodynamic therapy applications:recent progress and perspectives

With the fast development of technology for the treatment of tumor and bacteria,photo-therapeutic strate-gies emerge as a kind of highly effective and common treatment,but the low tissue penetration depth of light limits their development.Sonodynamic therapy(SDT),as an efficient and non-invasive treatment,attracts more people's attention due to the inherent property of high tissue penetration.The soft tissue penetration depth of ultrasound(US)can even reach more than 10 cm,which has great advantage over that of light.Therefore,many sonosensitizers are studied and applied to SDT-based therapy.Metal-based inorganic nanocrystals are able to generate more reactive oxygen species(ROS)due to the special composition and band structure.The representative achievements and the specific functions of the nanocrystals sonosensitizers are summarized in this work,and the relationship of structure/composition-SDT performance and the internally regulated composite is revealed.Syner-gistic effects of SDT in combination with other therapeutic modalities are mainly highlighted.At the same time,the critical and potential issues and future perspectives are addressed.

O-glycosyltransferases from Homo sapiens contributes to the biosynthesis of Glycyrrhetic Acid 3-O-mono-β-D-glucuronide and Glycyrrhizin in Saccharomyces cerevisiae

Glycyrrhizin(GL)and Glycyrrhetic Acid 3-O-mono-β-D-glucuronide(GAMG)are the typical triterpenoid glycosides found in the root of licorice,a popular medicinal plant that exhibits diverse physiological effects and pharmacological manifestations.However,only few reports are available on the glycosylation enzymes involved in the biosynthesis of these valuable compounds with low conversion yield so far.In mammals,glycosyltransferases are involved in the phase II metabolism and may provide new solutions for us to engineer microbial strains to produce high valued compounds due to the substrate promiscuity of these glycosyltransferases.In this study,we mined the genomic databases of mammals and evaluated 22 candidate genes of O-glycosyltransferases by analyzing their catalytic potential for O-glycosylation of the native substrate,glycyrrhetinic acid(GA)for its glycodiversification.Out of 22 selected glycosyltransferases,only UGT1A1 exhibited high catalytic performance for biosynthesis of the key licorice compounds GL and GAMG.Molecular docking results proposed that the enzymatic activity of UGT1A1 was likely owing to the stable hydrogen bonding interactions and favorite conformations between the amino acid residues around substrate channels(P82~R85)and substrates.Furthermore,the complete biosynthesis pathway of GL was reconstructed in Saccharomyces cerevisiae for the first time,resulting in the production of 5.98±0.47 mg/L and 2.31±0.21 mg/L of GL and GAMG,respectively.

Ionizable liposomal siRNA therapeutics enables potent and persistent treatment of Hepatitis B

Small interfering RNA(siRNA)constitutes a promising therapeutic modality supporting the potential functional cure of hepatitis B.A novel ionizable lipidoid nanoparticle(RBP131)and a state-of-the-art lyophilization technology were developed in this study,enabling to deliver siRNA targeting apolipoprotein B(APOB)into the hepatocytes with an ED_(50)of 0.05 mg/kg after intravenous injection.In addition,according to the requirements of Investigational New Drug(IND)application,a potent siRNA targeting hepatitis B virus(HBV)was selected and encapsulated with RBP131 to fabricate a therapeutic formulation termed RB-HBV008.

Biosafety materials:Ushering in a new era of infectious disease diagnosis and treatment with the CRISPR/Cas system

Despite multiple virus outbreaks over the past decade,including the devastating coronavirus disease 2019(COVID-19)pandemic,the lack of accurate and timely diagnosis and treatment technologies has wreaked havoc on global biosecurity.The clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated proteins(Cas)system has the potential to address these critical needs for tackling infectious diseases to detect viral nucleic acids and inhibit viral replication.This review summarizes how the CRISPR/Cas system is being utilized for the treatment and diagnosis of infectious diseases with the help of biosafety materials and highlights the design principle and in vivo and in vitro efficacy of advanced biosafety materials used to deal with virus attacks.

Single-atom cobalt nanozymes promote spinal cord injury recovery by anti-oxidation and neuroprotection

Oxidative stress and inflammation are central pathophysiological processes in a traumatic spinal cord injury(SCI).Antioxidant therapies that reduce the reactive oxygen and nitrogen species(RONS)overgeneration and inflammation are proved promising for improving the outcomes.However,efficient and long-lasting antioxidant therapy to eliminate multiple RONS with effective neuroprotection remains challenging.Here,a single-atom cobalt nanozyme(Co-SAzyme)with a hollow structure was reported to reduce the RONS and inflammation in the secondary injury of SCI.Among SAzymes featuring different single metal-N sites(e.g.,Mn,Fe,Co,Ni,and Cu),this Co-SAzyme showed a versatile property to eliminate hydrogen peroxide(H_(2)O_(2)),superoxide anion(O_(2)·^(-)),hydroxyl radical(·OH),nitric oxide(·NO),and peroxynitrite(ONOO^(-))that overexpressed in the early stage of SCI.The porous hollow structure also allowed the encapsulation and sustained release of minocycline for neuroprotection in synergy.In vitro results showed that the Co-SAzyme reduced the apoptosis and pro-inflammatory cytokine levels of microglial cells under oxidative stress.In addition,the Co-SAzyme combined with minocycline achieved remarkable improved functional recovery and neural repairs in the SCI-rat model.

Modular Synthesis of Tetraurea and Octaurea Macrocycles Encoded with Specific Monomer Sequences

Intermolecular hydrogen bonding among urea units grants prominent mechanical strength to polyurea elastomer materials.However,such interactions can cause significant solubility problems when synthesizing oligourea macrocycles with a large number of urea units,and it remains unknown for macrocycles containing more than six urea units.Here,we demonstrate a two-step,modular strategy for making a new class of tetraurea and octaurea macrocycles using commercially available building blocks.Intramolecular hydrogen bonding within the fundamental o-phenylene bis(urea)unit is the key to overcoming intermolecular hydrogen bonding to form favorable conformations for ring-closure reactions.The size and monomer sequences can be controlled by varying the flexibility of the spacers.Rigid diphenyl methylene and diphenyl ether linkers selectively afford tetraurea macrocycles,whereas the flexible hexylene linker produces octaurea macrocycles.Macrocycles encoded with two different spacers were also made.All these macrocycles are confirmed by X-ray diffraction structural analysis of the complexed forms with sulfate anions.Interestingly,a unique“figure-eight”structure is observed for the complex of MUH octaurea macrocycle with two encapsulated sulfate anions.Our study shows a paradigm of making large oligourea macrocycles with designer properties in a programable manner with tunable monomer sequences.

Lipid-Based Intelligent Vehicle Capabilitized with Physical and Physiological Activation

Intelligent drug delivery system based on “stimulus-response”mode emerging a promising perspective in next generation lipidbased nanoparticle.Here,we classify signal sources into physical and physiological stimulation according to their origin.

pH-Responsive polymer boosts cytosolic siRNA release for retinal neovascularization therapy

Small interfering RNA(siRNA)has a promising future in the treatment of ocular diseases due to its high efficiency,specificity,and low toxicity in inhibiting the expression of target genes and proteins.However,due to the unique anatomical structure of the eye and various barriers,delivering nucleic acids to the retina remains a significant challenge.In this study,we rationally design PACD,an A-B-C type non-viral vector copolymer composed of a hydrophilic PEG block(A),a siRNA binding block(B)and a pH-responsive block(C).PACDs can self-assemble into nanosized polymeric micelles that compact siRNAs into polyplexes through simple mixing.By evaluating its pH-responsive activity,gene silencing efficiency in retinal cells,intraocular distribution,and anti-angiogenesis therapy in a mouse model of hypoxia-induced angiogenesis,we demonstrate the efficiency and safety of PACD in delivering siRNA in the retina.We are surprised to discover that,the PACD/siRNA polyplexes exhibit remarkable intracellular endosomal escape efficiency,excellent gene silencing,and inhibit retinal angiogenesis.Our study provides design guidance for developing efficient nonviral ocular nucleic acid delivery systems.

siRNA-functionalized lanthanide nanoparticle enables efficient endosomal escape and cancer treatment

Attaching DNA/RNA to nanomaterials is the basis for nucleic acid-based assembly and drug delivery.Herein,we report that small interfering RNA(siRNA)effectively coordinates with ligand-free lanthanide nanoparticles(NaGdF4 NPs),and forms siRNA/NaGdF4 spherical nucleic acids(SNA).The coordination is primarily attributed to the interaction between Gd and phosphate backbone of the siRNA.Surprisingly,an efficient encapsulation and rapid endosomal escape of siRNA from the endosome/lysosome were achieved,due to its flexible ability to bound to phospholipid head of endosomal membrane,thereby disrupting the membrane structure.Resorting to the dual properties of NaGdF4 NPs,siRNA loading,and endosomal escape,siRNA targeting programmed cell death-ligand 1(siPD-L1)/NaGdF4 SNA triggers significant gene silencing in vitro and in vivo,and effectively represses the tumor growth in both CT26 tumor model and 4T1 orthotopic murine model.

Peptide-Based Electrochemical Biosensors and Their Applications in Disease Detection

Biosensors based on small molecule peptides have developed rapidly in the detection of disease markers with the characteristics of high sensitivity, rapid analysis speed and easy miniaturization. The properties of the sensor, such as the sensitivity and detection range, are closely related to the material and structure of the electrodes. The electrodes mainly used in peptidebased biosensors are gold electrodes, glassy carbon electrodes(GCE), indium tin oxide(ITO) conductive glass electrodes and screen-printed electrodes. In addition, to improve the biomolecule loading rate, antifouling performance, electrical conductivity of the biosensor, a variety of nanomaterials and organic molecules are used to construct the biosensor for disease detection. This review summarizes the properties of several commonly used electrodes for peptide-based electrochemical biosensors, and introduces some modified materials of the electrode and their effects on sensor performance. In the future,the peptide-based biosensors will be widely used in clinical detection and other related fields.

Microreactor platform for continuous synthesis of electronic doped quantum dots

Electronic doped quantum dots(Ed-QDs),by heterovalent cations doping,have held promise for future device concepts in optoelectronic and spin-based technologies due to their broadband Stokes-shifted luminescence,enhanced electrical transport and tailored magnetic behavior.Considering their scale-up requirement and the low yielding of several current colloidal synthesis methods,a stable and efficient bulk synthesis strategy must be developed.Microreactors have long been recognized as an effective platform for producing nanomaterials and fabricating large-scale structures.Here,we chose microreactor platform for continuous synthesis of Ed-QDs in the air at low temperatures.By original reverse cation exchange reaction mechanism together with varying the kinetic conditions of microreactor platform,such as liquid flow rate,the Ag doped CdS(CdS:Ag)Ed-QDs with higher yield have been synthesized successfully due to the continuous synthesis advantages with a high degree of size selectivity.Enabled by microreactor engineering simulation,this research not only provides a new synthetic method towards scale-up production but also enables to improve chemical mass production of similar functional QDs for optical devices,bioimaging and innovative information processing applications.

Transporter Engineering in Microbial Cell Factory Boosts Biomanufacturing Capacity

Microbial cell factories (MCFs) are typical and widely used platforms in biomanufacturing for designing and constructingsynthesis pathways of target compounds in microorganisms. In MCFs, transporter engineering is especially significant forimproving the biomanufacturing efficiency and capacity through enhancing substrate absorption, promoting intracellular masstransfer of intermediate metabolites, and improving transmembrane export of target products. This review discusses thecurrent methods and strategies of mining and characterizing suitable transporters and presents the cases of transporterengineering in the production of various chemicals in MCFs.