Transglutaminase mediated PEGylation of nanobodies for targeted nano-drug delivery

Integrated strategies for efficient production of Streptomyces mobaraensis transglutaminase in Komagataella phaffii

Transglutaminase (TGase) from Streptomyces mobaraensis commonly used to improve protein-based foods due to its unique enzymatic reactions, which imply considerable attention in its production. Recently, TGase exhibit broad market potential in non-food industries. However, achieving efficient synthesis of TGase remains a significant challenge. Herein, we achieved a substantial amount of a fully functional and kinetically stable TGase produced by Komagataella phaffii (Pichia pastoris) using multiple strategies including Geneticin (G418) screening, combinatorial mutations, promoter optimization, and co-expression. The active TGase expression reached a maximum of 10.1 U mL-1 in shake flask upon 96 h of induction, which was 3.8-fold of the wild type. Also, the engineered strain exhibited a 6.4-fold increase in half-life and a 2-fold increase in specific activity, reaching 172.67 min at 60 °C (t1/2(60 °C)) and 65.3 U mg-1, respectively. Moreover, the high-cell density cultivation in 5-L fermenter was also applied to test the productivity at large scale. Following optimization at a fermenter, the secretory yield of TGase reached 47.96 U mL-1 in the culture supernatant. Given the complexity inherent in protein expression and secretion, our research is of great significance and offers a comprehensive guide for improving the production of a wide range of heterologous proteins.

Molecular and functional insight into anti-EGFR nanobody: Theranostic implications for malignancies

Targeted therapy and imaging are the most popular techniques for the intervention and diagnosis of cancer. A potential therapeutic target for the treatment of cancer is the epidermal growth factor receptor (EGFR), primarily for glioblastoma, lung, and breast cancer. Over-production of ligand, transcriptional up-regulation due to autocrine/paracrine signalling, or point mutations at the genomic locus may contribute to the malfunction of EGFR in malignancies. This exploit makes use of EGFR, an established biomarker for cancer diagnostics and treatment. Despite considerable development in the last several decades in making EGFR inhibitors, they are still not free from limitations like toxicity and a short serum half-life. Nanobodies and antibodies share similar binding properties, but nanobodies have the additional advantage that they can bind to antigenic epitopes deep inside the target that conventional antibodies are unable to access. For targeted therapy, anti-EGFR nanobodies can be conjugated to various molecules such as drugs, peptides, toxins and photosensitizers. These nanobodies can be designed as novel immunoconjugates using the universal modular antibody-based platform technology (UniCAR). Furthermore, Anti-EGFR nanobodies can be expressed in neural stem cells and visualised by effective fluorescent and radioisotope labelling.

Enhancing Tumor Immunotherapy by Multivalent Anti-PD-L1 Nanobody Assembled via Ferritin Nanocage

Increasing immunotherapy response rate and durability can lead to significant improvements in cancer care. To address this challenge, a novel multivalent immune checkpoint therapeutic platform is constructed through site-specific ligation of anti-PD-L1 nanobody (Nb) on ferritin (Ftn) nanocage. Nb-Ftn blocks PD-1/PD-L1 interaction and downregulates PD-L1 levels via endocytosis-induced degradation. In addition, the cage structure of Ftn allows encapsulation of indocyanine green (ICG), an FDA-approved dye. Photothermal treatment with Nb-Ftn@ICG induces immunogenic death of tumor cells, which improves systemic immune response via maturation of dendritic cells and enhanced infiltration of T cells. Moreover, Nb-Ftn encapsulation significantly enhances cellular uptake, tumor accumulation and retention of ICG. In vivo assays showed that this nanoplatform ablates the primary tumor, suppresses abscopal tumors and inhibits tumor metastasis, leading to a prolonged survival rate. This work presents a novel strategy for improving cancer immunotherapy using multivalent nanobody-ferritin conjugates as immunological targeting and enhancing carriers.

Transglutaminase in Foods and Biotechnology

Stabilization and reusability of enzyme transglutaminase (TGM) are important goals for the enzymatic process since immobilizing TGM plays an important role in different technologies and industries. TGM can be used in many applications. In the food industry, it plays a role as a protein-modifying enzyme, while, in biotechnology and pharmaceutical applications, it is used in mediated bioconjugation due to its extraordinary crosslinking ability. TGMs (EC 2.3.2.13) are enzymes that catalyze the formation of a covalent bond between a free amino group of protein-bound or peptide-bound lysine, which acts as an acyl acceptor, and the γ-carboxamide group of protein-bound or peptide-bound glutamine, which acts as an acyl donor. This results in the modification of proteins through either intramolecular or intermolecular crosslinking, which improves the use of the respective proteins significantly.

Aptamers and nanobodies as alternatives to antibodies for ligand-targeted drug delivery in cancer

Targeted drug delivery (TDD) is the selective delivery of a therapeutic agent specifically to the site of action to avoid adverse effects and systemic toxicity and to reduce the dose required. Ligand TDD or active TDD involves using a ligand-drug conjugate comprising a targeting ligand linked to an active drug moiety that can either be free or encapsulated within a nanocarrier (NC). Aptamers are single-stranded oligonucleotides that bind to specific biomacromolecules because of their 3D conformation. Nanobodies are the variable domains of unique heavy chain-only antibodies (HcAbs) produced by animals of the Camelidae family. Both these types of ligand are smaller than antibodies and have been used to efficiently target drugs to particular tissues or cells. In this review, we describe the applications of aptamers and nanobodies as ligands for TDD, their advantages and disadvantages compared with antibodies, and the various modalities for targeting cancers using these ligands. Teaser: Aptamers and nanobodies are macromolecular ligands that can actively chaperone drug molecules to particular cancerous cells or tissues in the body to target their pharmacological effects and improve their therapeutic index and safety.

Protein encapsulation of nanocatalysts: A feasible approach to facilitate catalytic theranostics

Enzyme-mimicking nanocatalysts, also termed nanozymes, have attracted much attention in recent years. They are considered potential alternatives to natural enzymes due to their multiple catalytic activities and high stability. However, concerns regarding the colloidal stability, catalytic specificity, efficiency and biosafety of nanomaterials in biomedical applications still need to be addressed. Proteins are biodegradable macromolecules that exhibit superior biocompatibility and inherent bioactivities; hence, the protein modification of nanocatalysts is expected to improve their bioavailability to match clinical needs. The diversity of amino acid residues in proteins provides abundant functional groups for the conjugation or encapsulation of nanocatalysts. Moreover, protein encapsulation can not only improve the overall performance of nanocatalysts in biological systems, but also bestow materials with new features, such as targeting and retention in pathological sites. This review aims to report the recent developments and perspectives of protein-encapsulated catalysts in their functional improvements, modification methods and applications in biomedicine.

Atomically dispersed Mn boosting photoelectrochemical SARS-CoV-2 spike protein immunosensing on carbon nitride

The sudden outbreak of coronavirus disease (COVID-19) triggered by SARS-CoV-2 infection has created a terrifying situation around the world. The spike protein of SARS-CoV-2 can act as an early biomarker for COVID-19. Therefore, controlling the spread of COVID-19 requires a low-cost, fast-response, and sensitive monitoring technique of spike protein. Herein, a photoelectrochemical (PEC) immunosensor for the detection of spike protein was constructed using the nanobody and an Mn (Ⅱ) modified graphitic carbon nitride (Mn/g-C₃N₄). The introduction of atomically dispersed Mn (Ⅱ) can accelerate the effective transfer and separation of photogenerated electron-hole pairs, which significantly boosts PEC performance of g-C₃N₄, thereby improving the detection sensitivity. As a recognition site, nanobody can achieve high-affinity binding to the spike protein, leading to a high sensitivity. The linear detection range of the proposed PEC immunosensor was 75 fg mL^-1 to 150 pg mL^-1, and the limit of detection was calculated to be 1.22 fg mL^-1. This stable and feasible PEC immunosensor would be a promising diagnostic tool for sensitively detecting spike protein of SARS-CoV-2.

SnoopLigase Enables Highly Efficient Generation of C-C-Linked Bispecific Nanobodies Targeting TNF-α and IL-17A

Bispecific antibodies (bis-Nbs) have been extensively developed since the concept was devised over the decades. Taking advantage of the superior characteristics of nanobodies, bis-Nbs exhibit an emerging tendency to become the new generation of research and diagnostic tools. Traditional strategies to connect the homo- or heterogeneous monomers are commonly applied, but there are still technical issues to generate the bispecific molecules as efficiently as designed. Here, we utilize SnoopLigase to directly tether the C terminus (C-C) of the tagged nanobodies against tumor necrosis factor-α (TNF-α) and interleukin-17A (IL-17A). Under optimal conditions, the yield of C-C-linked bis-Nbs can reach as high as 70% due to the existence of SnoopLigase. The prepared bis-Nbs possessed similar or even higher affinity as the monomers and significantly inhibited the proliferation and migration of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) induced by TNF-α and IL-17A. This study provides an innovative route for using SnoopLigase to realize a highly efficient generation of C-C-linked bis-Nbs. The approach can be applied to different and multicomponent systems for their potential applications in disease diagnosis and treatment.

Delivery of cisplatin and resiquimod in nanomicelles for the chemoimmunotherapy of ovarian cancer

Background

To explore the effect and mechanism of delivery of cisplatin (CDDP) and resiquimod in nanomicelles for the chemoimmunotherapy of ovarian cancer in vivo and in vitro.

Methods

Poly(l-glutamic acid)-graft-methoxypolyethylene glycols (PLG-g-mPEG) was used to carry cisplatin and resiquimod for the preparation of CDDP/resiquimod/PLG-g-mPEG. We determined the loading content (LC) and encapsulation efficiency (EE), and then observed the particle shape, particle size distribution and zeta potential. In this study, we recruited 30 healthy adult participants and isolated mononuclear cells, and they were randomly classified into a control group, a CDDP group, a resiquimod group, a CDDP/resiquimod/PLG-g-mPEG group and a IFN-γ + LPS group to identify macrophages markers in different polarization states. We conducted microprobe synchrotron radiation X-ray fluorescence (SRXRF) imaging to observe the cell uptake. Furthermore, we observed the effects of CDDP/resiquimod/PLG-g-mPEG on the growth and colony formation of SW626 cells and the expressions of apoptosis-associated genes and proteins. Tumor-bearing mouse models of ovarian cancer were prepared and randomized into a negative control group, a PLG-g-mPEG group, a CDDP group, a resiquimod group and a CDDP/resiquimod/PLG-g-mPEG group, so as to analyze the anti-cancer effect of CDDP/resiquimod/PLG-g-mPEG in vivo.

Results

The LC and EE of CDDP/resiquimod/PLG-g-mPEG were 19.42% and 90.12%, respectively. Nanoparticles were uniform spherical in shape and closely arranged together, with a typical core–shell structure, and their average particle size and zeta potential were 82.36 nm and − 23.69 mV, respectively. When CDDP/resiquimod/PLG-g-mPEG group was compared with the control group, the positive expression rate of CD16 in the CDDP/resiquimod/PLG-g-mPEG group highly increased, whereas the positive expression rate of CD163 dramatically decreased. In the meantime, Arg1 and Mrc1 mRNA expressions significantly decreased whereas IL-12 and NOS2 mRNA expressions dramatically increased (P < 0.05). Elemental mapping of cells exhibited notable internalization of cisplatin delivered by CDDP/resiquimod/PLG-g-mPEG to cytoplasm. We compared the cell survival rate between the CDDP/resiquimod/PLG-g-mPEG group and the control group, the CDDP/resiquimod/PLG-g-mPEG group sharply reduced (P < 0.05). What’s more, the inhibitory effect got strengthened as the reaction time was prolonged, with the synergy coefficient of 0.31.

Conclusion

PLG-g-mPEG-loaded CDDP and resiquimod effectively achieves the targeted delivery of chemotherapy and immunotherapy, with a strong synergistic anti-cancer effect.

Novel development strategies and challenges for anti-Her2 antibody-drug conjugates

Antibody-drug conjugates (ADCs) combining potent cytotoxicity of small-molecule drugs with the selectivity and excellent pharmacokinetic profile of monoclonal antibody (mAb) are promising therapeutic modalities for a diverse range of cancers. Owing to overexpression in a wide range of tumors, human epidermal growth factor receptor 2 (Her2) is one of the most utilized targeting antigens for ADCs to treat Her2-positive cancers. Owing to the high density of Her2 antigens on the tumor cells and high affinity and high internalization capacity of corresponding antibodies, 56 anti-Her2 ADCs which applied >10 different types of novel payloads had entered preclinical or clinical trials. Seven of 12 Food and Drug Administration (FDA)-approved ADCs including Polivy (2019), Padcev (2019), EnHertu (2019), Trodelvy (2020), Blenrep (2020), Zynlonta (2021), and Tivdak) (2021) have been approved by FDA in the past three years alone, indicating that the maturing of ADC technology brings more productive clinical outcomes. This review, focusing on the anti-Her2 ADCs in clinical trials or on the market, discusses the strategies to select antibody formats, the linkages between linker and mAb, and effective payloads with particular release and action mechanisms for a good clinical outcome.

Microbial transglutaminase nanoflowers as an alternative nanomedicine for breast cancer theranostics

Breast cancer is the most common malignancy among women. With the aim of decreasing the toxicity of conventional breast cancer treatments, an alternative that could provide appropriate and effective drug utilization was envisioned. Thus, we contemplated and compared the in vitro effects of microbial transglutaminase nanoflowers (MTGase NFs) on breast cancer cells (MCF-7). Transglutaminase is an important regulatory enzyme acting as a site-specific cross-linker for proteins. With the versatility of MTGase facilitating the nanoflower formation by acting as molecular glue, it was demonstrated to have anti-cancer properties. The rational drug design based on a transglutaminase enzyme-assisted approach led to the uniform shape of petals in these nanoflowers, which had the capacity to act directly as an anti-cancer drug. Herein, we report the anti-cancer characteristics portrayed by enzymatic MTGase NFs, which are biocompatible in nature. This study demonstrated the prognostic and therapeutic significance of MTGase NFs as a nano-drug in breast cancer treatment. The results on MCF-7 cells showed a significantly improved in vitro therapeutic efficacy. MTGase NFs were able to exhibit inhibitory effects on cell viability (IC₅₀-8.23 μg ml⁻¹) within 24 h of dosage. To further substantiate its superior anti-proliferative role, the clonogenic potential was measured to be 62.8%, along with migratory inhibition of cells (3.76-fold change). Drastic perturbations were induced (4.61-fold increase in G0/G1 phase arrest), pointed towards apoptotic induction with a 58.9% effect. These results validated the role of MTGase NFs possessing a cytotoxic nature in mitigating breast cancer. Thus, MTGase bestows distinct functionality towards therapeutic nano-modality, i.e., nanoflowers, which shows promise in cancer treatment.

Development of a novel therapeutic nano-modality in the form of enzymatic transglutaminase nanoflowers; endowed with anti-cancerous action against breast cancers.

Application of lanthanide-doped upconversion nanoparticles for cancer treatment: a review

With the excellent ability to transform near-infrared light to localized visible or UV light, thereby achieving deep tissue penetration, lanthanide ion-doped upconversion nanoparticles (UCNP) have emerged as one of the most striking nanoscale materials for more effective and safer cancer treatment. Up to now, UCNPs combined with photosensitive components have been widely used in the delivery of chemotherapy drugs, photodynamic therapy and photothermal therapy. Applications in these directions are reviewed in this article. We also highlight microenvironmental tumor monitoring and precise targeted therapies. Then we briefly summarize some new trends and the existing challenges for UCNPs. We hope this review can provide new ideas for future cancer treatment based on UCNPs.

Conjugation of oxaliplatin with PEGylated-nanobody for enhancing tumor targeting and prolonging circulation

Oxaliplatin is a platinum-based drug used in clinic for cancer chemotherapy. Despite of its success, the non-selective effect on normal cells causes severe side-effects and hampers its applications. Targeted delivery of oxaliplatin to cancer cells is an effective approach to enhance drug efficacy and reduce adverse effect. In this work, the Pt(IV) prodrug of oxaliplatin has been conjugated to poly(ethylene glycol) (PEG) modified nanobody in order to achieve tumor targeting as well as improved circulation in vivo. The Pt(IV) prodrug was site-specifically linked to an anti-epidermal growth factor receptor (EGFR) nanobody, so that the drug can be accumulated more pronounced in EGFR positive tumor cells than in normal cells. The effect of different length of PEG on the drug circulation has been investigated, while the fusion of anti-albumin nanobody was used for comparison. The result demonstrates that the prolonged drug circulation significantly increases the in vivo drug efficiency of the oxaliplatin-nanobody conjugate.

CPPs to the Test: Effects on Binding, Uptake and Biodistribution of a Tumor Targeting Nanobody

Nanobodies are well-established targeting ligands for molecular imaging and therapy. Their short circulation time enables early imaging and reduces systemic radiation exposure. However, shorter circulation time leads to lower tracer accumulation in the target tissue. Cell-penetrating peptides (CPPs) improve cellular uptake of various cargoes, including nanobodies. CPPs could enhance tissue retention without compromising rapid clearance. However, systematic investigations on how the functionalities of nanobody and CPP combine with each other at the level of 2D and 3D cell cultures and in vivo are lacking. Here, we demonstrate that conjugates of the epidermal growth factor receptor (EGFR)-binding nanobody 7D12 with different CPPs (nonaarginine, penetratin, Tat and hLF) differ with respect to cell binding and induction of endocytosis. For nonaarginine and penetratin we compared the competition of EGF binding and performance of L- and D-peptide stereoisomers, and tested the D-peptide conjugates in tumor cell spheroids and in vivo. The D-peptide conjugates showed better penetration into spheroids than the unconjugated 7D12. Both in vivo and in vitro, the behavior of the agent reflects the combination of both functionalities. Although CPPs cause promising increases in in vitro uptake and 3D penetration, the dominant effect of the CPP in the control of biodistribution warrants further investigation.

Nanobodies as efficient drug-carriers: Progress and trends in chemotherapy

Nanobodies (Nb) have a promising future as a part of next generation chemodrug delivery systems. Nb, or VHH, are small (15 kDa) monomeric antibody fragments consisting of the antigen binding region of heavy chain antibodies. Heavy chain antibodies are naturally produced by camelids, however the structure of their VHH regions can be readily reproduced in industrial expression systems, such as bacteria or yeast. Due to their small size, high solubility, remarkable stability, manipulatable characteristics, excellent in vivo tissue penetration, conjugation advantages, and ease of production, Nb have many advantages when compared against their antibody precursors. In this review, we discuss the generation and selection of Nbs via phage display libraries for easy screening, and the conjugation techniques involved in creating target-specific nanocarriers. Furthermore, we provide a comprehensive overview of recent developments and perspectives in the field of Nb drug conjugates (NDCs) and Nb-based drug vehicles (NDv) with respect to antitumor therapeutics.

Interaction standards for biophysics: anti-lysozyme nanobodies

There is a significant demand in the molecular biophysics community for robust standard samples. They are required by researchers, instrument developers and pharmaceutical companies for instrumental quality control, methodological development and in the design and validation of devices, diagnostics and instrumentation. To-date there has been no clear consensus on the need and type of standards that should be available and different research groups and instrument manufacturers use different standard systems which significantly hinders comparative analysis. One of the major objectives of the Association of Resources for Biophysical Research in Europe (ARBRE) is to establish a common set of standard samples that can be used throughout the biophysics community and instrument developers. A survey was circulated among ARBRE members to ascertain the requirements of laboratories when using standard systems and the results are documented in this article. In summary, the major requirements are protein samples which are cheap, relatively small, stable and have different binding strengths. We have developed a panel of sdAb’s or ‘nanobodies’ against hen-egg white lysozyme with different binding strengths and suitable stability characteristics. Here we show the results of the survey, the selection procedure, validation and final selection of a panel of nanobody interaction standards.

Clustered nanobody-drug conjugates for targeted cancer therapy

A clustered Nb-drug conjugate (cNDC@PEG) was designed using anti-EGFR Nb to specifically deliver Pt(iv) prodrugs to tumors. cNDC@PEG efficiently targets EGFR positive tumor cells, and the clustered cNDC@PEG is more efficient in inhibiting tumor growth in vivo than the monomeric NDC. This work provides a novel strategy for the construction of a multi-valent NDC using dendrimers.

Paper Title "Hu7CG2: A Novel Humanized Anti-Epidermal Growth Factor Receptor (EGFR) Biparatopic Nanobody"

Targeted therapy is an effective and appropriate approach with low side effects in cancer therapy compared with other treatment approaches. Epidermal growth factor receptor, EGFR, is a favorable biomarker as targeted therapy because it overexpresses in several cancers. Monoclonal antibodies are common agents for targeted therapy. Nanobody is the smallest format of monoclonal antibodies with unique properties that include hiding epitope targeting, high stability, low production cost, and ease of connection to other components. The main challenge in targeted therapy by monoclonal antibodies is their immunogenicity due to their non-human nature. In this study, we designed, constructed, and evaluated a novel humanized anti- EGFR biparatopic nanobody, hu7CG2. The hu7CG2 was designed by grafting the complementarity-determining regions of two camelid anti- EGFR nanobodies known as 7C12 and EG2 to a universal scaffold and then connected with a glycine-serine linker. The results of antigen-binding activity and cell viability assays showed that the hu7CG2 inhibited the growth of EGFR overexpression tumor cells. The data showed that hu7CG2 might be a useful tool in the targeting and treatment of tumor cells.

Nanobody: A Small Antibody with Big Implications for Tumor Therapeutic Strategy

The development of monoclonal antibody treatments for successful tumor-targeted therapies took several decades. However, the efficacy of antibody-based therapy is still confined and desperately needs further improvement. Nanobodies are the recombinant variable domains of heavy-chain-only antibodies, with many unique properties such as small size (~15kDa), excellent solubility, superior stability, ease of manufacture, quick clearance from blood, and deep tissue penetration, which gain increasing acceptance as therapeutical tools and are considered also as building blocks for chimeric antigen receptors as well as for targeted drug delivery. Thus, one of the promising novel developments that may address the deficiency of monoclonal antibody-based therapies is the utilization of nanobodies. This article provides readers the significant factors that the structural and biochemical properties of nanobodies and the research progress on nanobodies in the fields of tumor treatment, as well as their application prospect.

Unique Benefits of Tumor-Specific Nanobodies for Fluorescence Guided Surgery

Tumor-specific fluorescence labeling is promising for real-time visualization of solid malignancies during surgery. There are a number of technologies to confer tumor-specific fluorescence. Antibodies have traditionally been used due to their versatility in modifications; however, their large size hampers efficient fluorophore delivery. Nanobodies are a novel class of molecules, derived from camelid heavy-chain only antibodies, that have shown promise for tumor-specific fluorescence labeling. Nanobodies are ten times smaller than standard antibodies, while maintaining antigen-binding capacity and have advantageous features, including rapidity of tumor labeling, that are reviewed in the present report. The present report reviews special considerations needed in developing nanobody probes, the status of current literature on the use of nanobody probes in fluorescence guided surgery, and potential challenges to be addressed for clinical translation.

Nanobody-A versatile tool for cancer diagnosis and therapeutics

In spite of the successful use of monoclonal antibodies (mAbs) in clinic for tumor treatment, their applications are still hampered in therapeutic development due to limitations, such as tumor penetration and high cost of manufacture. Nanobody, a single domain antibody that holds the strong antigen targeting and binding capacity, has demonstrated various advantages relative to antibody. Nanobody is considered as a next-generation of antibody-derived tool in the antigen related recognition and modulation. A number of nanobodies have been developed and evaluated in different stages of clinical trials for cancer treatment. Here we summarized the current progress of nanobody in tumor diagnosis and therapeutics, particularly on the conjugation of nanobody with functional moieties. The nanobody conjugation of diagnostic agents, such as radionuclide and optical tracers, can achieve specific tumor imaging. The nanobody-drug conjugates can enhance the therapeutic efficacy of anti-tumor drugs and reduce the adverse effects. The decoration of nanobody on nanodrug delivery systems can further improve the drug targeting to specific tumors. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Targeted nanobody complex enhanced photodynamic therapy for lung cancer by overcoming tumor microenvironment

Background

To investigate the efficacy of a PLGA-based nanobody complex in photodynamic therapy (PDT) and NIR-II imaging in A549 tumor hypoxic model.

Method

IR1048-MZ was firstly synthesized by conjugating a nitro imidazole group to IR1048. IR1048-MZ and Cat were then encapsulated in PLGA-SH solution. Anti-EGFR-Nanobody was also expressed and purified, and finally Anti-EGFR-Nanobody@PLGA-IR1048MZ-Cat (Nb@IC-NPs) nanobody complex was obtained based on the formation of desulfide bond between PLGA-SH and Anti-EGFR-Nanobody. Size distribution and morphology were characterized by TEM and DLS. Spectrum of Nb@IC-NPs towards NTR was measured by UV and fluorescence, while the particle’s selective response was studied using fluorescence. The uptake of Nb@IC-NPs in A549 cells was observed by flow cytometry and CLSM. In the meantime, its’ catalytic ability that decomposes H₂O₂ both extra-and intra-cellular was observed by fluorescence and CLSM. In vitro photodynamic toxicity of Nb@IC-NPs was examined by MTT, Live/Dead Cell Staining, Flow Cytometry and Apoptosis Assay. Tumor-bearing model was constructed to observe a semi-quantitative fluorescent distribution and the possibility of NIR-II fluorescence/photoacoustic (PA) imaging. Effect of Nb@IC-NPs on enhancing A549 tumor hypoxia and expression profile of HIF-1α was investigated in the presence of NIR. An A549 tumor metastasis model was also constructed to confirm the complex’ potential to destroy primary tumor, inhibit lung metastasis, and prolong mice’ survival. Lastly, impact of Nb@IC-NPs on mice’ main organs and blood indices was observed.

Results

Nb@IC-NPs was successfully fabricated with good homogeneity. The fluorescent absorbance of Nb@IC-NPs showed a linear relationship with the concentration of NTR, and a higher concentration of NTR corresponded to a stronger photoacoustic signal. In addition, Nb@IC-NPs showed a stable selectivity toward NTR. Our results also suggested a high efficient uptake of Nb@IC-NPs in A549 cells, which was more efficient than IC-NPs and IR1048-MZ alone. In vitro assays confirmed the effects of Nb@IC-NPs on catalytic O₂ generation even in hypoxic cells. The cell viability was upregulated with the nanocomplex at the absence of the laser, whereas it was dramatically declined with laser treatment that excited at 980 nm. Nb@IC-NPs achieved tumor hypoxia NIR-II/PA imaging through assisting A549 gathering. When NIR was applied, Nb@IC-NPs can significantly relieve A549 cellular/tumor hypoxia by generating more reactive oxygen species (ROS), which in turn helps lower the expression level of HIF-1α. In summary, Nb@IC-NPs based PDT can efficiently decimate A549 primary tumor, inhibit metastatic lung cancer, and prolong the lifespan of the mice under tolerable dosage. At last, in vivo toxicity tests of the nanocomplex showed its biosafety to the main organs and normal blood indices values.

Conclusion

Nb@IC-NPs improves tumor hypoxia through catalytic reaction and lowers the expression level of HIF-1α. It achieves tumor PA imaging through intensified NIR-II fluorescence signal that caused by response of the complex to the lesion’s nitroreductase (NTR). Nb@IC-NPs based PDT can efficiently kill A549 primary tumor, inhibit a lung metastasis, as well as prolong mice’ survival cycle.

Nanobody-Ferritin Conjugate for Targeted Photodynamic Therapy

Ferritin is an iron-storage protein nanocage that is assembled from 24 subunits. The hollow cavity of ferritin enables its encapsulation of various therapeutic agents; therefore, ferritin has been intensively investigated for drug delivery. The use of antibody-ferritin conjugates provides an effective approach for targeted drug delivery. However, the complicated preparation and limited protein stability hamper wide applications of this system. Herein, we designed a novel nanobody-ferritin platform (Nb-Ftn) for targeted drug delivery. The site-specific conjugation between nanobody and ferritin is achieved by transglutaminase-catalyzed protein ligation. This ligation strategy allows the Nb conjugation after drug loading in ferritin, which avoids deactivation of the nanobody under the harsh pH environment required for drug encapsulation. To verify the tumor targeting of this Nb-Ftn platform, a photodynamic reagent, manganese phthalocyanine (MnPc), was loaded into the ferritin cavity, and an anti-EGFR nanobody was conjugated to the surface of the ferritin. The ferritin nanocage can encapsulate about 82 MnPc molecules. This MnPc@Nb-Ftn conjugate can be efficiently internalized by EGFR positive A431 cancer cells, but not by EGFR negative MCF-7 cells. Upon 730 nm laser irradiation, MnPc@Nb-Ftn selectively killed EGFR positive A431 cells by generating reactive oxygen species (ROS), whereas no obvious damage was observed on MCF-7 cells. Given that ferritin can be used for encapsulation of various therapeutic agents, this work provides a strategy for facile construction of nanobody-ferritin for targeted drug delivery.

Generation and Application of Fluorescent Anti-Human β2-Microglobulin VHHs via Amino Modification

The functionalization of VHHs enables their application in almost every aspect of biomedical inquiry. Amino modification remains a common strategy for protein functionalization, though is considered to be inferior to site-specific methods and cause protein property changes. In this paper, four anti-β2M VHHs were selected and modified on the amino group by NHS-Fluo. The impacts of amino modification on these VHHs were drastically different, and among all th examples, the modified NB-1 maintained the original stability, bioactivity and homogeneity of unmodified NB-1. Specific recognition of VHHs targeting β2M detected by fluorescence imaging explored the possible applications of VHHs. Via this study, we successfully functionalized the anti-β2M VHHs through amino modification and the results are able to instruct the simple and fast functionalization of VHHs in biomedical researches.

Modular design of nanobody-drug conjugates for targeted-delivery of platinum anticancer drugs with an MRI contrast agent

A multifunctional nanobody-drug conjugate (NDC) was constructed in this work for the targeted delivery of a platinum prodrug and an MRI contrast agent. The NDC can be specifically internalized into EGFR positive cancer cells, resulting in higher therapeutic effect and lower side-effects relative to cisplatin. The Gd-binding domain enables the in situ detection of the drug distribution in vivo.

Progressive release of mesoporous nano-selenium delivery system for the multi-channel synergistic treatment of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease with a complex pathogenesis. Controlled release, target ability, and multi-channel synergistic treatment are key factors associated with the success of AD drugs. Herein, we report a novel mesoporous nano-selenium (MSe) release delivery system (MSe-Res/Fc-β-CD/Bor) based on the borneol (Bor) target, β-cyclodextrin nanovalves (Fc-β-CD) with loaded resveratrol (Res). Previous experiments have shown that MSe-Res/Fc-β-CD/Bor first releases Bor by interacting with blood or intracellular esterases, allowing the nanosystem to pass through the blood-brain barrier (BBB). Subsequently, the Fc-β-CD is opened by the redox (H₂O₂) response to the release of Res at the lesion site. We demonstrated that MSe-Res/Fc-β-CD/Bor inhibited aggregation of β-amyloid proteins (Aβ), mitigated oxidative stress, and suppressed tau hyperphosphorylation, while protecting nerve cells and successfully improving memory impairment in APP/PS1 mice. Interestingly, compared with rivastigmine (Riv) positive drugs alone, the MSe/Fc-β-CD/Bor loaded with Riv had a better pharmacokinetic index. These results indicate that MSe-Res/Fc-β-CD/Bor could be a prospective drug for treating AD.