Dual-functional protein for one-step production of a soluble and targeted fluorescent dye

A customized self-assembled synergistic biocatalyst for plastic depolymerization

The enzymatic degradation of plastic offers a green, sustainable strategy and scalable circular carbon route for solving polyester waste. Among the earlies discovered plastic-degrading enzymes are PET hydrolase (PETase) and MHET hydrolase (MHETase), which act synergistically. To promote the adsorption of enzymes on PET surfaces, increase their robustness, and enable directly depolymerization, we designed hydrophobin HFBI fused-PETase and MHETase. A customized self-assembled synergistic biocatalyst (MC@CaZn-MOF) was further developed to promote the two-step depolymerization process. The tailored catalysts showed better adhesion to the PET surface and desirable durability, retaining over 70% relative activity after incubation at pH 8.0 and 60 °C for 120 h. Importantly, MC@CaZn-MOF could directly decompose untreated AGf-PET to generate 9.5 mM TPA with weight loss over 90%. The successful implementation of a bifunctional customized catalyst makes the large-scale biocatalytic degradation of PET feasible, contributing to polymer upcycling and environmental sustainability.

Peptide-Directed Synthesis of Aggregation-Induced Emission Enhancement-Active Gold Nanoclusters for Single- and Two-Photon Imaging of Lysosome and Expressed αvβ3 Integrin Receptors

This study explores the synthesis and characterization of aggregation-induced emission enhancement (AIEE)-active gold nanoclusters (AuNCs), focusing on their near-infrared luminescence properties and potential applications in biological imaging. These AIEE-active AuNCs were synthesized via the NaBH4-mediated reduction of HAuCl4 in the presence of peptides. We systematically investigated the influence of the peptide sequence on the optical features of the AuNCs, highlighting the role of glutamic acid in enhancing their quantum yield (QY). Among the synthesized peptide-stabilized AuNCs, EECEE-stabilized AuNCs exhibited the maximum QY and a pronounced AIEE effect at pH 5.0, making them suitable for the luminescence imaging of intracellular lysosomes. The AIEE characteristic of the EECEE-stabilized AuNCs was demonstrated through examinations using transmission electron microscopy, dynamic light scattering, zeta potential analysis, and single-particle imaging. The formation of the EECEE-stabilized AuNCs was confirmed by size-exclusion chromatography and mass spectrometry. Spectroscopic and electrochemical examinations uncover the formation process of EECEE-stabilized AuNCs, comprising EECEE-mediated reduction, NaBH4-induced nucleation, complex aggregation, and subsequent cluster growth. Furthermore, we demonstrated the utility of these AuNCs as luminescent probes for intracellular lysosomal imaging, leveraging their pH-responsive AIEE behavior. Additionally, cyclic arginylglycylaspartic acid (RGD)-modified AIEE dots, derived from cyclic RGD-linked peptide-induced aggregation of EECEE-stabilized AuNCs, were developed for single- and two-photon luminescence imaging of αvβ3 integrin receptor-positive cancer cells.

BODIPY as a Multifunctional Theranostic Reagent in Biomedicine: Self-Assembly, Properties, and Applications

The use of boron dipyrromethene (BODIPY) in biomedicine is reviewed. To open, its synthesis and regulatory strategies are summarized, and inspiring cutting-edge work in post-functionalization strategies is highlighted. A brief overview of assembly model of BODIPY is then provided: BODIPY is introduced as a promising building block for the formation of single- and multicomponent self-assembled systems, including nanostructures suitable for aqueous environments, thereby showing the great development potential of supramolecular assembly in biomedicine applications. The frontier progress of BODIPY in biomedical application is thereafter described, supported by examples of the frontiers of biomedical applications of BODIPY-containing smart materials: it mainly involves the application of materials based on BODIPY building blocks and their assemblies in fluorescence bioimaging, photoacoustic imaging, disease treatment including photodynamic therapy, photothermal therapy, and immunotherapy. Lastly, not only the current status of the BODIPY family in the biomedical field but also the challenges worth considering are summarized. At the same time, insights into the future development prospects of biomedically applicable BODIPY are provided.

Curcumin-Encapsulated Fusion Protein-Based Nanocarrier Demonstrated Highly Efficient Epidermal Growth Factor Receptor-Targeted Treatment of Colorectal Cancer

Curcumin, a polyphenol derived from turmeric, has multiple biological functions, such as anti-inflammatory, antioxidant, antibacterial and, above all, antitumor activity. Colorectal cancer is a common malignancy of the gastrointestinal tract with an extremely high mortality rate. However, the low bioavailability and poor targeting properties of curcumin generally limit its clinical application. In the present study, we designed a fusion protein GE11-HGFI as a nanodrug delivery system. The protein was connected by flexible linkers, inheriting the self-assembly properties of hydrophobin HGFI and the targeting ability of GE11. The data show that the encapsulation of curcumin by fusion protein GE11-HGFI can form uniform and stable nanoparticles with a size of only 80 nm. In addition, the nanocarrier had high encapsulation efficiency for curcumin and made it to release sustainably. Notably, the drug-loaded nanosystem selectively targeted colorectal cancer cells with high epidermal growth factor receptor expression, resulting in high aggregated concentrations of curcumin at tumor sites, thus showing a significant anticancer effect. These results suggest that the nanocarrier fusion protein has the potential to be a novel strategy for enhancing molecular bioactivity and drug targeting in cancer therapy.

Biodegradation of highly crystallized poly(ethylene terephthalate) through cell surface codisplay of bacterial PETase and hydrophobin

The process of recycling poly(ethylene terephthalate) (PET) remains a major challenge due to the enzymatic degradation of high-crystallinity PET (hcPET). Recently, a bacterial PET-degrading enzyme, PETase, was found to have the ability to degrade the hcPET, but with low enzymatic activity. Here we present an engineered whole-cell biocatalyst to simulate both the adsorption and degradation steps in the enzymatic degradation process of PETase to achieve the efficient degradation of hcPET. Our data shows that the adhesive unit hydrophobin and degradation unit PETase are functionally displayed on the surface of yeast cells. The turnover rate of the whole-cell biocatalyst toward hcPET (crystallinity of 45%) dramatically increases approximately 328.8-fold compared with that of purified PETase at 30 °C. In addition, molecular dynamics simulations explain how the enhanced adhesion can promote the enzymatic degradation of PET. This study demonstrates engineering the whole-cell catalyst is an efficient strategy for biodegradation of PET.

Emerging prospects of protein/peptide-based nanoassemblies for drug delivery and vaccine development

Proteins have been widely used in the biomedical field because of their well-defined architecture, accurate molecular weight, excellent biocompatibility and biodegradability, and easy-to-functionalization. Inspired by the wisdom of nature, increasing proteins/peptides that possess self-assembling capabilities have been explored and designed to generate nanoassemblies with unique structure and function, including spatially organized conformation, passive and active targeting, stimuli-responsiveness, and high stability. These characteristics make protein/peptide-based nanoassembly an ideal platform for drug delivery and vaccine development. In this review, we focus on recent advances in subsistent protein/peptide-based nanoassemblies, including protein nanocages, virus-like particles, self-assemblable natural proteins, and self-assemblable artificial peptides. The origin and characteristics of various protein/peptide-based assemblies and their applications in drug delivery and vaccine development are summarized. In the end, the prospects and challenges are discussed for the further development of protein/peptide-based nanoassemblies.

The tumor phototherapeutic application of nanoparticles constructed by the relationship between PTT/PDT efficiency and 2,6- and 3,5-substituted BODIPY derivatives

BODIPY dyes have recently been used for photothermal and photodynamic therapy of tumors. However, complex multi-material systems, multiple excitation wavelengths and the unclear relationship between BODIPY structures and their PTT/PDT efficiency are still major issues. In our study, nine novel BODIPY near-infrared dyes were designed and successfully synthesized and then, the relationships between BODIPY structures and their PTT/PDT efficiency were investigated in detail. The results showed that modifications at position 3,5 of the BODIPY core with conjugated structures have better effects on photothermal and photodynamic efficiency than the modifications at position 2,6 with halogen atoms. Density functional theory (DFT) calculations showed that this is mainly due to the extension of the conjugated chain and the photoinduced electron transfer (PET) effect. By encapsulating BDPX-M with amphiphilic DSPE-PEG₂₀₀₀-RGD and lecithin, the obtained NPs not only show good water solubility and biological stability, but also could act as superior agents for photothermal and photodynamic synergistic therapy of tumors. Finally, we obtained BODIPY NPs that exhibited excellent photothermal and photodynamic effects at the same time under single irradiation with an 808 nm laser (photothermal conversion efficiency: 42.76%, A/A₀: ∼0.05). In conclusion, this work provides a direction to design and construct phototherapeutic nanoparticles based on BODIPY dyes for tumor treatment.

Supramolecular ensembles modified by near-infrared dyes and their biological applications

Near-infrared dyes possess the qualities of lower interference with biological autofluorescence, low photon scattering, and deep tissue penetration, and are being increasingly involved in the development of biomaterials for sensing and precision medicine. However, dyes usually suffer from the disadvantages of poor water solubility and photobleaching, factors that limit their application in vivo. The introduction of supramolecular ensembles can provide an ideal solution. This review presents recently developed supramolecular ensembles modified by near-infrared dyes. Compared with small-molecule fluorophores, the specific size of a supramolecular-based fluorophore endows it with longer circulation time in the bloodstream, increasing its chances of reaching a specific target. In addition, the construction of supramolecule-based fluorophores with versatile functions can be achieved by simple encapsulation or doping, instead of by complicated chemical synthesis. Thus, supramolecular-complex-based fluorophores offer high potential in diagnosis and therapy. This review outlines four different species of near-infrared dye based ensembles in terms of their method of formation, including simple encapsulation or doping and copolymerisation. Recently, a new technology has employed modified fluorophores for in situ self-assembly that form supramolecular ensembles at a specific position, thus solving the problem of poor uptake of nanoparticles by cells, and is included in this review. Finally, the future of this field is considered.

Microwave-assisted synthesis of meso-carboxyalkyl-BODIPYs and an application to fluorescence imaging

In this study, a significantly improved method for the synthesis of modular meso-BODIPY (boron dipyrromethene) derivatives possessing a free carboxylic acid group (which was subsequently coupled to peptides), is disclosed. This method provides a vastly efficient synthetic route with a > threefold higher overall yield than other reports. The resultant meso-BODIPY acid allowed for further easy incorporation into peptides. The meso-BODIPY peptides showed absorption maxima from 495-498 nm and emission maxima from 504-506 nm, molar absorptivity coefficients from 33 383-80 434 M-1 cm-1 and fluorescent quantum yields from 0.508-0.849. The meso-BODIPY-c(RGDyK) peptide was evaluated for plasma stability and (proved to be durable even up to 4 h) was then assessed for its fluorescence imaging applicability in vivo and ex vivo. The optical imaging in vivo was limited due to autofluorescence, however, the ex vivo tissue analysis displayed BODIPY-c(RGDyK) internalization and cancer detection thereby making it a novel tumor-integrin associated fluorescent probe while displaying the lack of interference the dye has on the properties of this ligand to bind the receptor.

Dual Functions of Ghz Frequency Acoustic Resonator System for Biosamples Capture and Sensing

This work reports a novel acoustic resonator system integrated dual functions of biological samples capture and amount monitoring on a single chip. The system could capture samples from nano-sized proteins to micro-sized cells on micro-sized chip precisely with controllable concentration, meanwhile the high sensitivity mass sensing was achieved during the capture process. The devices were further applied to study the cell growth and cytotoxicity. Results indicated that it was possible to capture and monitor the physiological changes in a single cell level. This work explores a new opportunity on the development of miniaturized multiplex biosensing devices on a single chip.

Non-oncological applications of RGD-based single-photon emission tomography and positron emission tomography agents

INTRODUCTION

Non-invasive imaging techniques (especially single-photon emission tomography and positron emission tomography) apply several RGD-based imaging ligands developed during a vast number of preclinical and clinical investigations. The RGD (Arg-Gly-Asp) sequence is a binding moiety for a large selection of adhesive extracellular matrix and cell surface proteins. Since the first identification of this sequence as the shortest sequence required for recognition in fibronectin during the 1980s, fundamental research regarding the molecular mechanisms of integrin action have paved the way for development of several pharmaceuticals and radiopharmaceuticals with clinical applications. Ligands recognizing RGD may be developed for use in the monitoring of these interactions (benign or pathological). Although RGD-based molecular imaging has been actively investigated for oncological purposes, their utilization towards non-oncology applications remains relatively under-exploited.

METHODS AND SCOPE

This review highlights the new non-oncologic applications of RGD-based tracers (with the focus on single-photon emission tomography and positron emission tomography). The focus is on the last 10 years of scientific literature (2009-2020). It is proposed that these imaging agents will be used for off-label indications that may provide options for disease monitoring where there are no approved tracers available, for instance Crohn's disease or osteoporosis. Fundamental science investigations have made progress in elucidating the involvement of integrin in various diseases not pertaining to oncology. Furthermore, RGD-based radiopharmaceuticals have been evaluated extensively for safety during clinical evaluations of various natures.

CONCLUSION

Clinical translation of non-oncological applications for RGD-based radiopharmaceuticals and other imaging tracers without going through time-consuming extensive development is therefore highly plausible. Graphical abstract.

SirT3 activates AMPK-related mitochondrial biogenesis and ameliorates sepsis-induced myocardial injury

Sirtuin-3 (SirT3) and AMPK stimulate mitochondrial biogenesis, which increases mitochondrial turnover and cardiomyocyte regeneration. We studied the effects of SirT3, AMPK, and mitochondrial biogenesis on sepsis-induced myocardial injury. Our data showed that after treating cardiomyocytes with lipopolysaccharide, SirT3 and AMPK levels decreased, and this was followed by mitochondrial dysfunction and cardiomyocyte death. Overexpression of SirT3 activated the AMPK pathway and improved mitochondrial biogenesis, which is required to sustain mitochondrial redox balance, maintain mitochondrial respiration, and suppress mitochondrial apoptosis. Inhibition of mitochondrial biogenesis abolished SirT3/AMPK-induced cardioprotection by causing mitochondrial damage. These findings indicate that SirT3 reduces sepsis-induced myocardial injury by activating AMPK-related mitochondrial biogenesis.

Acetonitrilated Unsymmetric BODIPYs having glycine fluorescence responsive quenching: Design, synthesis and spectroscopic properties

A series of novel N≡C-CH₂-B-F system BODIPY were designed and synthesized by introducing aldehyde and acetonitrile units which gave positive influence to spectroscopic and chemical properties of BODIPY derivatives. The effects of glycine (Gly) on the target products were studied via ultraviolet and visible spectrophotometry (UV-Vis) and photoluminescence (PL) under different conditions of the presence and absence of cations (K⁺, Ca²⁺, Zn²⁺). It was showed that glycine has an intense quenching effect on the compounds in both the presence and absence of ions with a dramatic color change from notable red to light orange owing to the addition of Gly. With regard to cells imaging investigation, the products showed the prominent fluorescence in cholangiocarcinoma cells. The luminescent effect of compounds 1 and 3 entering the cells was significantly stronger than that of compound 2. In addition, pertaining to anticancer properties, two human cancer cell lines (RBE, HCCC-9810) and one normal cell line (L-02) were evaluated for in vitro cytotoxicity. The target compounds, 1-3, exhibited moderate antitumor activity, of which compound 1 was found to be the most potent derivative with IC₅₀ values of 119.31 ± 6.25, 114.73 ± 3.25, and 106.33 ± 5.22 against RBE, HCCC-9810, and L-02 cells, respectively, slightly weaker than the positive control 5-FU.

Suppressor of ras val-2 promotes inflammation-mediated oxidative stress and cell apoptosis in cardiomyocytes through activating Mst1-mROS signaling pathway

Context: Reperfusion injury after myocardial infarction is associated with inflammation response and oxidative stress.Aim: The aim of our study is to explore the influence of suppressor of ras val-2 (SRV2) on cardiomyocyte oxidative stress and inflammation response under hypoxia-reoxygenation (HR) injury.Methods: Cell viability was determined via MTT assay. qPCR and western blots were used to analyze the alterations of SRV2 and mammalian STE20-like protein kinases 1 (Mst1). ELISA and qPCR were used to verify the alterations of antioxidants and pro-inflammatory factors.Results: SRV2 was upregulated by HR injury in cardiomyocyte. Interestingly, loss of SRV2 attenuated HR injury-mediated cardiomyocyte damage through inhibiting cardiomyocyte apoptosis. At the molecular levels, SRV2 deletion reduced inflammation and oxidative stress induced by HR injury and thus promoted cardiomyocyte survival. Besides, SRV2 deletion inactivated the Mst1-mROS signaling pathway in cardiomyocyte and thus regulated the inflammation and oxidative stress. Interestingly, overexpression of Mst1 abolished the beneficial effects exerted by SRV2 deletion on HR-mediated cardiomyocyte death.Conclusions: SRV2 upregulation, induced by reperfusion injury, contributes to cardiomyocyte death through the Mst1-mROS signaling pathway.

Targeted and pH-facilitated theranostic of orthotopic gastric cancer via phase-transformation doxorubicin-encapsulated nanoparticles enhanced by low-intensity focused ultrasound (LIFU) with reduced side effect

Purpose

Focused ultrasound-mediated chemotherapy, as a non-invasive therapeutic modality, has been extensively explored in combating deep tumors for predominant penetration performance. However, the generally used high-intensity focused ultrasound (HIFU) inevitably jeopardizes normal tissue around the lesion for hyperthermal energy. To overcome this crucial issue, low-intensity focused ultrasound (LIFU) was introduced to fulfill precisely controlled imaging and therapy in lieu of HIFU. The objective of this study was to develop a facile and versatile nanoplatform (DPP-R) in response to LIFU and provide targeted drug delivery concurrently.

Methods

Multifunctional DPP-R was fabricated by double emulsion method and carbodiimide method. Physicochemical properties of DPP-R were detected respectively and the bio-compatibility and bio-safety were evaluated by CCK-8 assay, blood analysis, and histologic section. The targeted ability, imaging function, and anti-tumor effect were demonstrated in vitro and vivo.

Results

The synthetic DPP-R showed an average particle size at 367 nm, stable physical-chemical properties in different media, and high bio-compatibility and bio-safety. DPP-R was demonstrated to accumulate at the tumor site by active receptor/ligand reaction and passive EPR effect with intravenous administration. Stimulated by LIFU at the tumor site, phase-transformable PFH was vaporized in the core of the integration offering contrast-enhanced ultrasound imaging. The stimuli led to encapsulated DOX's initial burst release and subsequent sustained release for anti-tumor therapy which was verified to be more effective and have less adverse effects than free DOX.

Conclusion

DPP-R combined with LIFU provides a novel theranostic modality for GC treatment with potent therapeutic effect, including prominent performance of targeting, ultrasound imaging, and accurate drug release.

Peptide-induced aggregation of glutathione-capped gold nanoclusters: A new strategy for designing aggregation-induced enhanced emission probes

A series of polymers and metal ions have been observed to be useful in triggering aggregation-induced emission (AIE) and AIE enhancement (AIEE) of thiolated gold nanoclusters (AuNCs). However, peptide-induced AIEE of thiolated AuNCs and their applications in biosensors have rarely been investigated. In this study, we showed that positively charged peptides induced efficient AIEE of negatively charged glutathione-capped AuNCs (GSH-AuNCs) through electrostatic attraction. In contrast to GSH-AuNCs, polyarginine (polyArg), a cationic peptide, stimulated the AIEE of the GSH-AuNCs, resulting in a 3.5-fold luminescence enhancement, 10-fold enhancement in quantum yield, 8-nm blueshift in the luminescence maximum, and a 2.1-fold increase in the mean luminescence lifetime. Four different AIEE-based biosensors with excellent selectivity and acceptable sensitivity were fabricated using cationic peptides as an AIEE-active trigger and as a biorecognition element. A heparin biosensor with a limit of detection (LOD) of 3 nM was constructed by combining AG73 peptide-mediated AIEE of the GSH-AuNCs and the specific interaction of AG73 peptides with heparin macromolecules. The concentration of human trypsin was selectively detected at a concentration as low as 1 nM using an arginine-glycine repeat peptide as an enzymatic substrate and as an AIEE-active trigger. Alkaline phosphatase (ALP)-catalyzed dephosphorylation of phosphopeptides paired with the corresponding product-mediated AIEE of the GSH-AuNCs was used for ALP sensing with an LOD of 0.3 U L^-1. A peptide consisting of a cyclic RGD unit and an AIEE-active unit was designed to synthesize RGD-modified GSH-AuNC aggregates that can target αvβ3 integrin receptors. These AIEE-based sensors were practically applied for the quantitative determination of heparin in human plasma, trypsin in human urine, and ALP in human plasma as well as for luminescent imaging of αvβ3 integrin-overexpressing HeLa cells.

Advances in intracellular delivery through supramolecular self-assembly of oligonucleotides and peptides

Cells utilize natural supramolecular assemblies to maintain homeostasis and biological functions. Naturally inspired modular assembly of biomaterials are now being exploited for understanding or manipulating cell biology for treatment, diagnosis, and detection of diseases. Supramolecular biomaterials, in particular peptides and oligonucleotides, can be precisely tuned to have diverse structural, mechanical, physicochemical and biological properties. These merits of oligonucleotides and peptides as building blocks have given rise to the evolution of numerous nucleic acid- and peptide-based self-assembling nanomaterials for various medical applications, including drug delivery, tissue engineering, regenerative medicine, and immunotherapy. In this review, we provide an extensive overview of the intracellular delivery approaches using supramolecular self-assembly of DNA, RNA, and peptides. Furthermore, we discuss the current challenges related to subcellular delivery and provide future perspectives of the application of supramolecular biomaterials for intracellular delivery in theranostics.